Based on the data of drilling,logging,experiment and gas testing in the Nanchuan area,southeastern Sichuan Basin,the hydrocarbon generation potential,gas genesis,occurrence state,migration,preservation conditions,pore...Based on the data of drilling,logging,experiment and gas testing in the Nanchuan area,southeastern Sichuan Basin,the hydrocarbon generation potential,gas genesis,occurrence state,migration,preservation conditions,pore and fracture features and accumulation evolution of the first member of Permian Maokou Formation(Mao 1 Member)are systematically studied,and the main controlling factors of unconventional gas enrichment and high production in marlstone assemblage of Mao 1 Member are discussed.(1)The enrichment and high yield of unconventional natural gas in the Mao 1 Member are controlled by three factors:carbon-rich fabric controlling hydrocarbon generation potential,good preservation controlling enrichment,and natural fracture controlling production.(2)The carbonate rocks of Mao 1 Member with carbon rich fabric have significant gas potential,exhibiting characteristics of self-generation and self-storage,which lays the material foundation for natural gas accumulation.(3)The occurrence state of natural gas is mainly free gas,which is prone to lateral migration,and good storage conditions are the key to natural gas enrichment.Positive structure is more conducive to natural gas accumulation,and a good compartment is created jointly by the self-sealing property of the Mao 1 Member and its top and bottom sealing property in monoclinal area,which is favorable for gas accumulation by retention.(4)Natural fractures are the main reservoir space and flow channel,and the more developed natural fractures are,the more conducive to the formation of high-quality porous-fractured reservoirs and the accumulation of natural gas,which is the core of controlling production.(5)The accumulation model of unconventional natural gas is proposed as“self-generation and self-storage,preservation controlling richness,and fractures controlling production”.(6)Identifying fracture development areas with good preservation conditions is the key to successful exploration,and implementing horizontal well staged acidizing and fracturing is an important means to increase production and efficiency.The study results are of referential significance for further understanding the natural gas enrichment in the Mao 1 Member and guiding the efficient exploration and development of new types of unconventional natural gas.展开更多
Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespre...Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.展开更多
A new type of amphiphiles bearingmacrocycle such as cucurbit[7]uril(CB[7])spontaneously forms a nanomaterial in water,specifically vesicles(tACB[7]vesicles)with a positive surface charge,verified through various analy...A new type of amphiphiles bearingmacrocycle such as cucurbit[7]uril(CB[7])spontaneously forms a nanomaterial in water,specifically vesicles(tACB[7]vesicles)with a positive surface charge,verified through various analytical techniques including TIRF,DLS and TEM.Functional validation not only reveals the accessibility of the CB[7]portal on these vesicles allowing CB[7]-based host-vip interactions with various functional vip molecules such as fluorescein isothiocyanate conjugated adamantylammonium and spermine(FITC-AdA and FITC-SPM,respectively)using confocal laser scanning microscopy,but also showcases the effective internalization of tACB[7]vesicles into cancer cells with the anticancer drug oxaliplatin(OxPt),as a vip to CB[7],through in vitro cell experiments.Hence,this study provides a blueprint to impart amphiphilic properties to CB[7]through synthetic design and highlights the potential of CB[7]derivatives as a new class of unconventional amphiphiles self-assembling into functional nanomaterials for advanced drug delivery.展开更多
Rising global energy needs have intensified the search for unconventional hydrocarbon sources,especially in under-selected areas like the Northeast Java Basin.This region harbors promising unconventional hydrocarbon r...Rising global energy needs have intensified the search for unconventional hydrocarbon sources,especially in under-selected areas like the Northeast Java Basin.This region harbors promising unconventional hydrocarbon reserves,where source rocks function as dual-phase systems for both hydrocarbon generation and storage.This research investigates how metal-based catalysts,particularly iron(Fe),can expedite hydrocarbon maturation in such reservoirs.Combining well logging,geochemical assessments,seismic data,and advanced lab techniques,including X-ray Diffraction(XRD),we pinpoint optimal zones for exploration.Results indicate that the Tuban,Kujung,and Ngimbang formations contain economically viable unconventional deposits,exhibiting tight reservoir properties(permeability:0.01–1 md)and moderate to good Total Organic Carbon(TOC)levels(1%–2%).Spatial analysis reveals elevated density concentrations in the northern sector,indicative of high-viscosity hydrocarbons typical of unconventional plays.Crucially,Fe additives were found to markedly enhance organic matter conversion,shortening maturation periods and boosting hydrocarbon yield.XRD data confirms that Fe alters crystalline configurations,increasing reactivity and speeding up thermal breakdown(shifting immature organic compounds toward maturity at an accelerated rate).These findings contribute to the evolving discourse on unconventional resource exploitation by proposing an innovative recovery enhancement strategy.The study also sets a precedent for investigating metal-assisted hydrocarbon conversion in geologically comparable basins globally.展开更多
We present work on a cavity-driven QED system combining an asymmetrical Fabry–Perot cavity and N two-level atoms(TLAs)and show the convenience of simplifying from distinguishable atoms to undistinguishable bosons whe...We present work on a cavity-driven QED system combining an asymmetrical Fabry–Perot cavity and N two-level atoms(TLAs)and show the convenience of simplifying from distinguishable atoms to undistinguishable bosons when the atoms are prepared in the same initial state.Such simplification is valid even when the atoms are not prepared in the inphase condition,since any partial in-phase initial state will evolve into the ground state through a relaxation process.Thus,we get a reduced group of differential equations by introducing the Dicke states,and the under-zero Lyapunov exponents verify its stability.We also work out the collective unconventional photon blockade(UCPB)and get two kinds of giant nonreciprocal UCPBs(NUCPBs)in the weak-driving approximation.Results show that we can employ N noninteracting bosonic atoms to generate a collective UCPB instead of a monoatomic UCPB as the UCPB conditions do not vary with the number of atoms.Furthermore,the forward giant NUCPB only occurring for N larger than a certain number as well as the backward giant NUCPB are controllable by the cavity asymmetry and by the number of atoms.Our findings suggest a prospective approach to the generation of quantum nonreciprocity by N identical atoms.展开更多
To satisfy the increasing global energy demand,while searching for new energy sources,it’s important to take a closer look at the resources already at our disposal and optimize their use.This comprehensive review exp...To satisfy the increasing global energy demand,while searching for new energy sources,it’s important to take a closer look at the resources already at our disposal and optimize their use.This comprehensive review explores the evolving landscape of unconventional oil resources,focusing on the environmental and economic implica-tions of bitumen partial upgrading technologies,particularly within the Canadian context.With over 55%of the world’s oil reserves comprising of unconventional oil,which includes extra-heavy oil and oil sand bitumen,there is a growing trend to shift from traditional oil sources to these abundant yet under-utilized reserves.This review delves into the challenges and advancements in bitumen partial upgrading,highlighting the latest technologies in thermal cracking,hydrocracking,catalytic cracking,and innovative methods like surfactant integration,cavi-tation,microwave,and plasma-assisted upgrading.It also discusses the environmental implications and eco-nomic feasibility of these technologies,emphasizing the necessity for sustainable and cost-effective solutions at petroleum field sites.Furthermore,the report introduces the transformative concept of Bitumen Beyond Com-bustion(BBC),which explores the non-combustion uses of bitumen and its asphaltene fraction in manufacturing high-value carbon-based products.These novel approaches align with global sustainability goals,offering the potential for significant reductions in greenhouse gas emissions and new routes to diversify the economic ap-plications of bitumen.The review then concludes with an assessment of current challenges and future research directions,advocating for a balanced approach that harmonizes technological innovation,environmental stewardship,and economic viability in the field of bitumen upgrading.展开更多
It is of great significance to study the failure mode of mining roadways for safe coal mining.The unconventional asymmetric failure(UAF)phenomenon was discovered in the 9106 ventilation roadway of Wangzhuang coal mine...It is of great significance to study the failure mode of mining roadways for safe coal mining.The unconventional asymmetric failure(UAF)phenomenon was discovered in the 9106 ventilation roadway of Wangzhuang coal mine in Shanxi Province.The main manifestation is that the deformation of the roadway on the coal side is much greater than that on the coal pillar side.A comprehensive study was conducted on on-site detection,theoretical analysis,laboratory tests and numerical simulation of the UAF phenomenon.On-site detection shows that the deformation of the coal sidewall can reach 50–80 cm,and the failure zone depth can reach 3 m.The deformation and fracture depth on the coal pillar side are much smaller than those on the coal side.A calculation model for the principal stress of surrounding rock when the axial direction of the roadway is inconsistent with the in-situ stress field was established.The distribution of the failure zone on both sides of the roadway has been defined by the combined mining induced stress.The true triaxial test studied the mechanical mechanism of rock mass fracture and crack propagation on both sides of the roadway.The research results indicate that the axial direction,stress field distribution,and mining induced stress field distribution of the roadway jointly affect the asymmetric failure mode of the roadway.The angle between the axis direction of the roadway and the maximum horizontal stress field leads to uneven distribution of the principal stress field on both sides.The differential distribution of mining induced stress exacerbates the asymmetric distribution of principal stress in the surrounding rock.The uneven stress distribution on both sides of the roadway is the main cause of UAF formation.The research results can provide mechanical explanations and theoretical support for the control of surrounding rock in roadways with similar failure characteristics.展开更多
In overpressure reservoirs,natural gas often coexists in a three-phase mixed form of continuous free state,dispersed free state and water-saturated dissolved state.However,the latter two have not received sufficient a...In overpressure reservoirs,natural gas often coexists in a three-phase mixed form of continuous free state,dispersed free state and water-saturated dissolved state.However,the latter two have not received sufficient attention.In response to this situation,based on detailed characterization of typical overpressure dissolved gas in the Yinggehai-Qiongdongnan basin and the experiment results of natural gas dissolution with high-temperature and overpressure,the concept of“overpressure-dissolved gas”was proposed and its basic features,formation conditions and resource potential were summarized.It refers to the natural gas present in the gas-water transitional zone and the saturated dissolved gas zone within the overpressure reservoirs.The formation of overpressure-dissolved gas requires two basic conditions:the pressure coefficient typically greater than 1.5,and a relatively high gas saturation in the reservoir(10%-35%).Overpressure-dissolved gas exists in the strata from shallow to deep with a multi-stage superimposed pattern;there are at least four combination types:overpressure-dissolved gas with multiple gas caps,overpressure-dissolved gas with single gas cap,gas-bearing water layer without gas cap,and dissolved gas-bearing water layer without gas cap.The basic geological elements required for the formation of overpressure-dissolved gas include the gas source,reservoir,cap rock,gas-water transitional zone and overpressure body.The conditions of gas source,reservoir and cap rock determine the scale of the overpressure-dissolved gas zone.High temperature,high pressure and low-permeability reservoirs control the solubility of natural gas and the thickness of the gas-water transitional zone.The physical properties of sandstone determine the combination types of overpressure-dissolved gas.Changes in pressure control the transformation of different existing states of overpressure-dissolved gas.The overpressure-dissolved gas in the Yinggehai-Qiongdongnan Basin has considerable huge resource potential.Once breakthrough is achieved in this area,it will usher in a new era of natural gas exploration in the overpressured basin.展开更多
Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transform...Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.展开更多
The Early Paleocene to Middle Eocene Apollonia Formation in the BED‒9 field has been particularly interesting for unconventional hydrocarbon exploration since its discovery in 2006.However,the multiscale compositional...The Early Paleocene to Middle Eocene Apollonia Formation in the BED‒9 field has been particularly interesting for unconventional hydrocarbon exploration since its discovery in 2006.However,the multiscale compositional and diagenetic inconsistencies present challenges for its characterization.This study aims to evaluate the petrophysical properties of the Apollonia Formation to locate the sweet-spot intervals.Moreover,it seeks to investigate reservoir rock types(RRTs),depositional settings,and the impact of diagenesis on reservoir quality.The findings of this study are as follows.1)The Apollonia A5 and C1 units are identified as"sweet-spot"intervals.Their effective porosity ranges from 18%to 35%,average permeability varies from 0.1 to 2.0 mD,and water saturation falls between 40%and 50%,indicating good reservoir quality.2)High-order eustatic sea-level changes and repetitive climatic change cycles significantly influence the alternating carbonate productivity and dilution cycles.Five distinct RRTs are classified,denoting a gradational facies change from clean,argillaceous,and carbonaceous chalky limestone to marl and interbedded shale intervals.3)Interpreting the electro-facies responses,collated with microfacies variations and faunal content,deepens our understanding of the depositional environment,which extends from the inner to outer-shelf setting.4)The diagenetic processes have a dual impact that enhances and diminishes the reservoir quality.Finally,the gap in evaluating the petrophysical characteristics of all the Apollonia members has been addressed based on integrating the petrophysical and facies analysis for A,B,and C members.The Apollonia Formation has unique characteristics as an unconventional hydrocarbon resource.展开更多
The new century has witnessed a strategic breakthrough in unconventional oil ＆ gas.Hydrocarbon accumulated in micro-/nano-scale pore throat shale systems has become an important domain that could replace current oil ...The new century has witnessed a strategic breakthrough in unconventional oil ＆ gas.Hydrocarbon accumulated in micro-/nano-scale pore throat shale systems has become an important domain that could replace current oil ＆ gas resources.Unconventional oil ＆ gas plays an increasingly important role in our energy demand.Tight gas,CBM,heavy oil and asphaltic sand have served as a key domain of exploration ＆ development,with tight oil becoming a ＇bright spot＇ domain and shale gas becoming a ＇hotspot＇ domain.China has made great breakthroughs in unconventional oil ＆ gas resources,such as tight gas,shale gas,tight oil and CBM,and great progress in oil shale,gas hydrate,heavy oil and oil sand.China has an estimated（223-263）×10~8t of unconventional oil resources and（890-1260）×l0^（12）m^3 of gas resources.China has made a breakthrough for progress in unconventional oil ＆ gas study.New progress achieved in fine-grained sedimentary studies related to continental open lacustrine basin large-scale shallow-water delta sand bodies,lacustrine basin central sandy clastic flow sediments and marine-continental fine-grained sediments provide a theoretical basis for the formation and distribution of basin central reservoir bodies.Great breakthroughs have been made in unconventional reservoir geology in respect of research methodology ＆ technology,multi-scale data merging and physical simulation of formation conditions.Overall characterization of unconventional reservoirs via multi-method and multi-scale becomes increasingly popular and facilitates the rapid development of unconventional oil ＆ gas geological theory,method and technology.The formation of innovative,continuous hydrocarbon accumulation theory,the establishment of the framework of the unconventional oil ＆ gas geological theory system,and the determination of the implications,geological feature,formation mechanism,distribution rule and core technology of unconventional oil＆ gas geological study lays a theoretical foundation for extensive unconventional oil ＆ gas exploration and development.Theories and technologies of unconventional oil ＆ gas exploration and development developed rapidly,including some key evaluation techniques such as ＇sweet spot zone＇ integrated evaluation and a six-property evaluation technique that uses hydrocarbon source,lithology,physical property,brittleness,hydrocarbon potential and stress anisotropy,and some key development ＆engineering technologies including micro-seismic monitoring,horizontal drilling ＆ completion and ＂factory-like＂ operation pattern, ＂man-made reservoir＂ development,which have facilitated the innovative development of unconventional oil ＆ gas.These breakthroughs define a new understanding in four aspects：①theoretical innovation;② key technologies;③ complete market mechanism and national policy support;and ④ well-developed ground infrastructure,which are significant for prolonging the life cycle of petroleum industry,accelerating the upgrade and development of theories and technologies and altering the global traditional energy structure.展开更多
As a milestone of the entire energy industry,unconventional resources have inevitably swept the world in the last decade,and will certainly dominate the global oil and gas industry in the near future.Eventually,the ＂...As a milestone of the entire energy industry,unconventional resources have inevitably swept the world in the last decade,and will certainly dominate the global oil and gas industry in the near future.Eventually,the ＂unconventional＂ will become ＂conventional＂.Along with the rapid development,however,some issues have emerged,which are closely related to the viability of unconventional resources development.Under the current circumstances of low crude oil and gas price,coupled with the prominent environmental concerns,the arguments about the development and production of unconventional resources have been recently heated up.This work introduced the fullblown aspects of unconventional resources especially shale reservoirs,by discussing their concepts and definitions,reviewing the shale gas and shale oil development history and necessity,analyzing the shale plays＇ geology and petroleum systems with respects to key hydrocarbon accumulation elements and mechanisms,and summarizing the technology resolution.This study also discussed the relevant key issues,including significant estimation uncertainty of technically recoverable resources,the equivocal understanding of complex geology preventing the production and technologies implementation optimization,the difficulties of experiences and technologies global expanding,and the corresponding risks and uncertainties.In addition,based on the latest production and exploration data,the future perspective of the unconventional resources was depicted from global unconventional resources assessments,technology development,and limitations constraining the development.展开更多
A velocity model is an important factor influencing microseismic event locations. We re- view the velocity modeling and inversion techniques for locating microseismic events in exploration for unconventional oil and g...A velocity model is an important factor influencing microseismic event locations. We re- view the velocity modeling and inversion techniques for locating microseismic events in exploration for unconventional oil and gas reservoirs. We first describe the geological and geophysical characteristics of reservoir formations related to hydraulic fracturing in heterogeneity, anisotropy, and variability, then discuss the influences of velocity estimation, anisotropy model, and their time-lapse changes on the accuracy in determining microseismic event locations, and then survey some typical methods for building velocity models in locating event locations. We conclude that the three tangled physical attributes of reservoirs make microseismic monitoring very challenging. The uncertainties in velocity model and ignoring its anisotropies and its variations in hydraulic fracturing can cause systematic mislocations of microseismie events which are unacceptable in microseismic monitoring. So, we propose some potential ways for building accurate velocity models.展开更多
Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the...Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the characteristic functions of transforming variants has been developed to simulate the formation and evolution of their microstructures. This approach is advantageous in its explicit material symmetry and energy well structure, minimal number of ma- terial coefficients, and easiness in coupling multiple physical processes and order parameters, and has been applied successfully to study the microstructures and macroscopic prop- erties of shape memory alloys, ferroelectrics, ferromagnetic shape memory alloys, and multiferroic magnetoelectric crys- tals and films with increased complexity. In this topical re- view, the formulation of this unconventional phase field approach will be introduced in details, and its applications to various transforming materials will be discussed. Some ex- amples of specific microstructures will also be presented.展开更多
Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with...Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with hydraulic fracturing in a relatively high confidence level and accuracy.In this study,we present a multidimensional DIRECT inversion method for microseismic locations and applicability tests over modeling data based on a downhole microseismic monitoring system.Synthetic tests inidcate that the objective function of locations can be defined as a multi-dimensional matrix space by employing the global optimization DIRECT algorithm,because it can be run without the initial value and objective function derivation,and the discretely scattered objective points lead to an expeditious contraction of objective functions in each dimension.This study shows that the DIRECT algorithm can be extensively applied in real downhole microseismic monitoring data from hydraulic fracturing completions.Therefore,the methodology,based on a multidimensional DIRECT algorithm,can provide significant high accuracy and convergent efficiency as well as robust computation for interpretable spatiotemporal microseismic evolution,which is more suitable for real-time processing of a large amount of downhole microseismic monitoring data.展开更多
The discovery of unconventional hydrocarbon resources since the late 20th century changed geologists’understanding of hydrocarbon migration and accumulations and provides a solution to energy shortage.In 2016,unconve...The discovery of unconventional hydrocarbon resources since the late 20th century changed geologists’understanding of hydrocarbon migration and accumulations and provides a solution to energy shortage.In 2016,unconventional oil production in the USA accounted for 41%of the total oil production;and unconventional natural gas production in China accounted for 35%of total gas production,showing strong growth momentum of unconventional hydrocarbons explorations.Unconventional hydrocarbons generally coexist with conventional petroleum resources;they sometimes distribute in a separate system,not coexisting with a conventional system.Identification and prediction of unconventional resources and their potentials are prominent challenges for geologists.This study analyzed the results of 12,237 drilling wells in six representative petroliferous basins in China and studied the correlations and differences between conventional and unconventional hydrocarbons by comparing their geological features.Migration and accumulation of conventional hydrocarbon are caused dominantly by buoyance.Wepropose a concept of buoyance-driven hydrocarbon accumulation depth to describe the deepest hydrocarbon accumulation depth driven dominantly by buoyance;beyond this depth the buoyance becomes unimportant for hydrocarbon accumulation.We found that the buoyance-driven hydrocarbon accumulation depth in petroliferous basins controls the different oil/gas reservoirs distribution and resource potentials.Hydrocarbon migration and accumulations above this depth is dominated by buoyancy,forming conventional reservoirs in traps with high porosity and permeability,while hydrocarbon migration and accumulation below this depth is dominated by non-buoyancy forces(mainly refers to capillary force,hydrocarbon volumeexpansion force,etc.),forming unconventional reservoirs in tight layers.The buoyance-driven hydrocarbon accumulation depths in six basins in China range from 1200mto 4200 m,which become shallowerwith increasing geothermal gradient,decreasing particle size of sandstone reservoir layers,or an uplift in the whole petroliferous basin.The predicted unconventional resource potential belowthe buoyance-driven hydrocarbon accumulation depth in six basins in China is more than 15.71×10^(9) t oil equivalent,among them 4.71×10^(9) t reserves have been proved.Worldwide,94%of 52,926 oil and gas reservoirs in 1186 basins are conventional reservoirs and only 6%of them are unconventional reservoirs.These 94%conventional reservoirs show promising exploration prospects in the deep area below buoyance-driven hydrocarbon accumulation depth.展开更多
The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some...The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.展开更多
A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes an...A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes and Euler equations based on a moving-embedded grid system and adaptive grid methodology.A combination of the third-order upwind scheme and flux-difference splitting scheme,instead of the second-order center-difference scheme which may cause larger wake dissipation,has been employed in the present computational fluid dynamics(CFD)method.The sound pressure data in the near field can be calculated directly by solving the Navier–Stokes equations,and the sound propagation can be predicted by the Kirchhoff method.A harmonic expansion approach is presented for rotor far-field noise prediction,which gives an analytical expression for the integral function in the Kirchhoff formula.As a result,the interpolation process is simplified and the efficiency and accuracy of the interpolation are improved.Then,the high-speed impulsive(HIS)noise of a helicopter rotor at different tip Mach numbers and on different observers is calculated and analyzed in hover and forward flight,which shows a highly directional characteristic of the rotor HIS noise with a maximum value in the rotor plane,and the HSI noise weakens rapidly with the increasing of the directivity angle.In order to investigate the effects of the rotor blade-tip shape on its aeroacoustic characteristics,four kinds of blade tips are designed and their noise characteristics have been simulated.At last,a new unconventional CLOR-II blade tip has been designed,and the noise characteristics of the presented CLOR-II model rotor have been simulated and measured compared to the reference rotors with a rectangular or swept-back platform blade tip.The results demonstrate that the unconventional CLOR-II blade tip can significantly reduce the HSI noise of a rotor.展开更多
The efficient exploration and development of unconventional oil and gas are critical for increasing the self-sufficiency of oil and gas supplies in China.However,such operations continue to face serious problems(e.g.,...The efficient exploration and development of unconventional oil and gas are critical for increasing the self-sufficiency of oil and gas supplies in China.However,such operations continue to face serious problems(e.g.,borehole collapse,loss,and high friction),and associated formation damage can severely impact well completion rates,increase costs,and reduce efficiencies.Water-based drilling fluids possess certain advantages over oil-based drilling fluids(OBDFs)and may offer lasting solutions to resolve the aforementioned issues.However,a significant breakthrough with this material has not yet been made,and major technical problems continue to hinder the economic and large-scale development of unconventional oil and gas.Here,the international frontier external method,which only improves drilling fluid inhibition and lubricity,is expanded into an internal-external technique that improves the overall wellbore quality during drilling.Bionic technologies are introduced into the chemical material synthesis process to imitate the activity of life.A novel drilling and completion fluid technique was developed to improve wellbore quality during drilling and safeguard formation integrity.Macroscopic and microscopic analyses indicated that in terms of wellbore stability,lubricity,and formation protection,this approach could outperform methods that use typical OBDFs.The proposed method also achieves a classification upgrade from environmentally protective drilling fluid to an ecologically friendly drilling fluid.The developed technology was verified in more than 1000 unconventional oil and gas wells in China,and the results indicate significant alleviation of the formation damage attributed to borehole collapse,loss,and high friction.It has been recognized as an effective core technology for exploiting unconventional oil and gas resources.This study introduces a novel research direction for formation protection technology and demonstrates that observations and learning from the natural world can provide an inexhaustible source of ideas and inspire the creation of original materials,technologies,and theories for petroleum engineering.展开更多
The presence of sealed or semi-sealed,multiscale natural fracture systems appears to be crucial for the successful stimulation of deep reservoirs.To explore the reaction of such systems to reservoir stimulation,a new ...The presence of sealed or semi-sealed,multiscale natural fracture systems appears to be crucial for the successful stimulation of deep reservoirs.To explore the reaction of such systems to reservoir stimulation,a new numerical simulation approach for hydraulic stimulation has been developed,trying to establish a realistic model of the physics involved.Our new model successfully reproduces dynamic fracture activation,network generation,and overall reservoir permeability enhancement.Its outputs indicate that natural fractures facilitate stimulation far beyond the near-wellbore area,and can significantly improve the hydraulic conductivity of unconventional geo-energy reservoirs.According to our model,the fracture activation patterns are jointly determined by the occurrence of natural fractures and the in situ stress.High-density natural fractures,high-fluid pressure,and low effective stress environments promote the formation of complex fracture networks during stimulation.Multistage or multicluster fracturing treatments with an appropriate spacing also increase the stimulated reservoir area(SRA).The simulation scheme demonstrated in this work offers the possibility to elucidate the complex multiphysical couplings seen in the field through detailed site-specific modeling.展开更多
基金Supported by the National Science and Technology Major Project of China(2016ZX05061)Sinopec Science and Technology Department Project(P21042-4,P25030)。
文摘Based on the data of drilling,logging,experiment and gas testing in the Nanchuan area,southeastern Sichuan Basin,the hydrocarbon generation potential,gas genesis,occurrence state,migration,preservation conditions,pore and fracture features and accumulation evolution of the first member of Permian Maokou Formation(Mao 1 Member)are systematically studied,and the main controlling factors of unconventional gas enrichment and high production in marlstone assemblage of Mao 1 Member are discussed.(1)The enrichment and high yield of unconventional natural gas in the Mao 1 Member are controlled by three factors:carbon-rich fabric controlling hydrocarbon generation potential,good preservation controlling enrichment,and natural fracture controlling production.(2)The carbonate rocks of Mao 1 Member with carbon rich fabric have significant gas potential,exhibiting characteristics of self-generation and self-storage,which lays the material foundation for natural gas accumulation.(3)The occurrence state of natural gas is mainly free gas,which is prone to lateral migration,and good storage conditions are the key to natural gas enrichment.Positive structure is more conducive to natural gas accumulation,and a good compartment is created jointly by the self-sealing property of the Mao 1 Member and its top and bottom sealing property in monoclinal area,which is favorable for gas accumulation by retention.(4)Natural fractures are the main reservoir space and flow channel,and the more developed natural fractures are,the more conducive to the formation of high-quality porous-fractured reservoirs and the accumulation of natural gas,which is the core of controlling production.(5)The accumulation model of unconventional natural gas is proposed as“self-generation and self-storage,preservation controlling richness,and fractures controlling production”.(6)Identifying fracture development areas with good preservation conditions is the key to successful exploration,and implementing horizontal well staged acidizing and fracturing is an important means to increase production and efficiency.The study results are of referential significance for further understanding the natural gas enrichment in the Mao 1 Member and guiding the efficient exploration and development of new types of unconventional natural gas.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204533,12434009,and 62476278)the National Key R&D Program of China(Grant No.2024YFA1408601)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant No.24XNKJ15)。
文摘Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.
基金supported by the National Research Foundation of Korea[NRF-2023–00211758].
文摘A new type of amphiphiles bearingmacrocycle such as cucurbit[7]uril(CB[7])spontaneously forms a nanomaterial in water,specifically vesicles(tACB[7]vesicles)with a positive surface charge,verified through various analytical techniques including TIRF,DLS and TEM.Functional validation not only reveals the accessibility of the CB[7]portal on these vesicles allowing CB[7]-based host-vip interactions with various functional vip molecules such as fluorescein isothiocyanate conjugated adamantylammonium and spermine(FITC-AdA and FITC-SPM,respectively)using confocal laser scanning microscopy,but also showcases the effective internalization of tACB[7]vesicles into cancer cells with the anticancer drug oxaliplatin(OxPt),as a vip to CB[7],through in vitro cell experiments.Hence,this study provides a blueprint to impart amphiphilic properties to CB[7]through synthetic design and highlights the potential of CB[7]derivatives as a new class of unconventional amphiphiles self-assembling into functional nanomaterials for advanced drug delivery.
文摘Rising global energy needs have intensified the search for unconventional hydrocarbon sources,especially in under-selected areas like the Northeast Java Basin.This region harbors promising unconventional hydrocarbon reserves,where source rocks function as dual-phase systems for both hydrocarbon generation and storage.This research investigates how metal-based catalysts,particularly iron(Fe),can expedite hydrocarbon maturation in such reservoirs.Combining well logging,geochemical assessments,seismic data,and advanced lab techniques,including X-ray Diffraction(XRD),we pinpoint optimal zones for exploration.Results indicate that the Tuban,Kujung,and Ngimbang formations contain economically viable unconventional deposits,exhibiting tight reservoir properties(permeability:0.01–1 md)and moderate to good Total Organic Carbon(TOC)levels(1%–2%).Spatial analysis reveals elevated density concentrations in the northern sector,indicative of high-viscosity hydrocarbons typical of unconventional plays.Crucially,Fe additives were found to markedly enhance organic matter conversion,shortening maturation periods and boosting hydrocarbon yield.XRD data confirms that Fe alters crystalline configurations,increasing reactivity and speeding up thermal breakdown(shifting immature organic compounds toward maturity at an accelerated rate).These findings contribute to the evolving discourse on unconventional resource exploitation by proposing an innovative recovery enhancement strategy.The study also sets a precedent for investigating metal-assisted hydrocarbon conversion in geologically comparable basins globally.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12164022 and 12174288)Natural Science Foundation of Jiangxi Province of China(Grant No.20232BAB201044)+1 种基金Scientific Research Foundation of the Education Department of Jiangxi Province of China(Grant No.GJJ211039)China Postdoctoral Science Foundation(Grant No.2023M732028)。
文摘We present work on a cavity-driven QED system combining an asymmetrical Fabry–Perot cavity and N two-level atoms(TLAs)and show the convenience of simplifying from distinguishable atoms to undistinguishable bosons when the atoms are prepared in the same initial state.Such simplification is valid even when the atoms are not prepared in the inphase condition,since any partial in-phase initial state will evolve into the ground state through a relaxation process.Thus,we get a reduced group of differential equations by introducing the Dicke states,and the under-zero Lyapunov exponents verify its stability.We also work out the collective unconventional photon blockade(UCPB)and get two kinds of giant nonreciprocal UCPBs(NUCPBs)in the weak-driving approximation.Results show that we can employ N noninteracting bosonic atoms to generate a collective UCPB instead of a monoatomic UCPB as the UCPB conditions do not vary with the number of atoms.Furthermore,the forward giant NUCPB only occurring for N larger than a certain number as well as the backward giant NUCPB are controllable by the cavity asymmetry and by the number of atoms.Our findings suggest a prospective approach to the generation of quantum nonreciprocity by N identical atoms.
文摘To satisfy the increasing global energy demand,while searching for new energy sources,it’s important to take a closer look at the resources already at our disposal and optimize their use.This comprehensive review explores the evolving landscape of unconventional oil resources,focusing on the environmental and economic implica-tions of bitumen partial upgrading technologies,particularly within the Canadian context.With over 55%of the world’s oil reserves comprising of unconventional oil,which includes extra-heavy oil and oil sand bitumen,there is a growing trend to shift from traditional oil sources to these abundant yet under-utilized reserves.This review delves into the challenges and advancements in bitumen partial upgrading,highlighting the latest technologies in thermal cracking,hydrocracking,catalytic cracking,and innovative methods like surfactant integration,cavi-tation,microwave,and plasma-assisted upgrading.It also discusses the environmental implications and eco-nomic feasibility of these technologies,emphasizing the necessity for sustainable and cost-effective solutions at petroleum field sites.Furthermore,the report introduces the transformative concept of Bitumen Beyond Com-bustion(BBC),which explores the non-combustion uses of bitumen and its asphaltene fraction in manufacturing high-value carbon-based products.These novel approaches align with global sustainability goals,offering the potential for significant reductions in greenhouse gas emissions and new routes to diversify the economic ap-plications of bitumen.The review then concludes with an assessment of current challenges and future research directions,advocating for a balanced approach that harmonizes technological innovation,environmental stewardship,and economic viability in the field of bitumen upgrading.
基金financially supported by the National Natural Science Foundation of China(Nos.52225404,12532020,52394192 and 42321002)Key Research and Development Program Projects of Xinjiang Uygur Autonomous Region(No.2024B03017)Doctoral Startup Foundation of Fuyang Normal University,China(No.2025KYQD0124)。
文摘It is of great significance to study the failure mode of mining roadways for safe coal mining.The unconventional asymmetric failure(UAF)phenomenon was discovered in the 9106 ventilation roadway of Wangzhuang coal mine in Shanxi Province.The main manifestation is that the deformation of the roadway on the coal side is much greater than that on the coal pillar side.A comprehensive study was conducted on on-site detection,theoretical analysis,laboratory tests and numerical simulation of the UAF phenomenon.On-site detection shows that the deformation of the coal sidewall can reach 50–80 cm,and the failure zone depth can reach 3 m.The deformation and fracture depth on the coal pillar side are much smaller than those on the coal side.A calculation model for the principal stress of surrounding rock when the axial direction of the roadway is inconsistent with the in-situ stress field was established.The distribution of the failure zone on both sides of the roadway has been defined by the combined mining induced stress.The true triaxial test studied the mechanical mechanism of rock mass fracture and crack propagation on both sides of the roadway.The research results indicate that the axial direction,stress field distribution,and mining induced stress field distribution of the roadway jointly affect the asymmetric failure mode of the roadway.The angle between the axis direction of the roadway and the maximum horizontal stress field leads to uneven distribution of the principal stress field on both sides.The differential distribution of mining induced stress exacerbates the asymmetric distribution of principal stress in the surrounding rock.The uneven stress distribution on both sides of the roadway is the main cause of UAF formation.The research results can provide mechanical explanations and theoretical support for the control of surrounding rock in roadways with similar failure characteristics.
基金Supported by the Key Project of Science and Technology Strategic Consulting,Chinese Academy of Engineering(2025-HZ-30).
文摘In overpressure reservoirs,natural gas often coexists in a three-phase mixed form of continuous free state,dispersed free state and water-saturated dissolved state.However,the latter two have not received sufficient attention.In response to this situation,based on detailed characterization of typical overpressure dissolved gas in the Yinggehai-Qiongdongnan basin and the experiment results of natural gas dissolution with high-temperature and overpressure,the concept of“overpressure-dissolved gas”was proposed and its basic features,formation conditions and resource potential were summarized.It refers to the natural gas present in the gas-water transitional zone and the saturated dissolved gas zone within the overpressure reservoirs.The formation of overpressure-dissolved gas requires two basic conditions:the pressure coefficient typically greater than 1.5,and a relatively high gas saturation in the reservoir(10%-35%).Overpressure-dissolved gas exists in the strata from shallow to deep with a multi-stage superimposed pattern;there are at least four combination types:overpressure-dissolved gas with multiple gas caps,overpressure-dissolved gas with single gas cap,gas-bearing water layer without gas cap,and dissolved gas-bearing water layer without gas cap.The basic geological elements required for the formation of overpressure-dissolved gas include the gas source,reservoir,cap rock,gas-water transitional zone and overpressure body.The conditions of gas source,reservoir and cap rock determine the scale of the overpressure-dissolved gas zone.High temperature,high pressure and low-permeability reservoirs control the solubility of natural gas and the thickness of the gas-water transitional zone.The physical properties of sandstone determine the combination types of overpressure-dissolved gas.Changes in pressure control the transformation of different existing states of overpressure-dissolved gas.The overpressure-dissolved gas in the Yinggehai-Qiongdongnan Basin has considerable huge resource potential.Once breakthrough is achieved in this area,it will usher in a new era of natural gas exploration in the overpressured basin.
基金support from the National Key Research and Development Program of China(2023YFE0120700)National Natural Science Foundation of China(52274041)Distinguished Young Sichuan Science Scholars(2023NSFSC1954).
文摘Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.
文摘The Early Paleocene to Middle Eocene Apollonia Formation in the BED‒9 field has been particularly interesting for unconventional hydrocarbon exploration since its discovery in 2006.However,the multiscale compositional and diagenetic inconsistencies present challenges for its characterization.This study aims to evaluate the petrophysical properties of the Apollonia Formation to locate the sweet-spot intervals.Moreover,it seeks to investigate reservoir rock types(RRTs),depositional settings,and the impact of diagenesis on reservoir quality.The findings of this study are as follows.1)The Apollonia A5 and C1 units are identified as"sweet-spot"intervals.Their effective porosity ranges from 18%to 35%,average permeability varies from 0.1 to 2.0 mD,and water saturation falls between 40%and 50%,indicating good reservoir quality.2)High-order eustatic sea-level changes and repetitive climatic change cycles significantly influence the alternating carbonate productivity and dilution cycles.Five distinct RRTs are classified,denoting a gradational facies change from clean,argillaceous,and carbonaceous chalky limestone to marl and interbedded shale intervals.3)Interpreting the electro-facies responses,collated with microfacies variations and faunal content,deepens our understanding of the depositional environment,which extends from the inner to outer-shelf setting.4)The diagenetic processes have a dual impact that enhances and diminishes the reservoir quality.Finally,the gap in evaluating the petrophysical characteristics of all the Apollonia members has been addressed based on integrating the petrophysical and facies analysis for A,B,and C members.The Apollonia Formation has unique characteristics as an unconventional hydrocarbon resource.
基金Funded by the National Key Basic Research and Development Program(973 Program),China(Grant 2014CB239000)China National Science and Technology Major Project(Grant 2011ZX05001)
文摘The new century has witnessed a strategic breakthrough in unconventional oil ＆ gas.Hydrocarbon accumulated in micro-/nano-scale pore throat shale systems has become an important domain that could replace current oil ＆ gas resources.Unconventional oil ＆ gas plays an increasingly important role in our energy demand.Tight gas,CBM,heavy oil and asphaltic sand have served as a key domain of exploration ＆ development,with tight oil becoming a ＇bright spot＇ domain and shale gas becoming a ＇hotspot＇ domain.China has made great breakthroughs in unconventional oil ＆ gas resources,such as tight gas,shale gas,tight oil and CBM,and great progress in oil shale,gas hydrate,heavy oil and oil sand.China has an estimated（223-263）×10~8t of unconventional oil resources and（890-1260）×l0^（12）m^3 of gas resources.China has made a breakthrough for progress in unconventional oil ＆ gas study.New progress achieved in fine-grained sedimentary studies related to continental open lacustrine basin large-scale shallow-water delta sand bodies,lacustrine basin central sandy clastic flow sediments and marine-continental fine-grained sediments provide a theoretical basis for the formation and distribution of basin central reservoir bodies.Great breakthroughs have been made in unconventional reservoir geology in respect of research methodology ＆ technology,multi-scale data merging and physical simulation of formation conditions.Overall characterization of unconventional reservoirs via multi-method and multi-scale becomes increasingly popular and facilitates the rapid development of unconventional oil ＆ gas geological theory,method and technology.The formation of innovative,continuous hydrocarbon accumulation theory,the establishment of the framework of the unconventional oil ＆ gas geological theory system,and the determination of the implications,geological feature,formation mechanism,distribution rule and core technology of unconventional oil＆ gas geological study lays a theoretical foundation for extensive unconventional oil ＆ gas exploration and development.Theories and technologies of unconventional oil ＆ gas exploration and development developed rapidly,including some key evaluation techniques such as ＇sweet spot zone＇ integrated evaluation and a six-property evaluation technique that uses hydrocarbon source,lithology,physical property,brittleness,hydrocarbon potential and stress anisotropy,and some key development ＆engineering technologies including micro-seismic monitoring,horizontal drilling ＆ completion and ＂factory-like＂ operation pattern, ＂man-made reservoir＂ development,which have facilitated the innovative development of unconventional oil ＆ gas.These breakthroughs define a new understanding in four aspects：①theoretical innovation;② key technologies;③ complete market mechanism and national policy support;and ④ well-developed ground infrastructure,which are significant for prolonging the life cycle of petroleum industry,accelerating the upgrade and development of theories and technologies and altering the global traditional energy structure.
文摘As a milestone of the entire energy industry,unconventional resources have inevitably swept the world in the last decade,and will certainly dominate the global oil and gas industry in the near future.Eventually,the ＂unconventional＂ will become ＂conventional＂.Along with the rapid development,however,some issues have emerged,which are closely related to the viability of unconventional resources development.Under the current circumstances of low crude oil and gas price,coupled with the prominent environmental concerns,the arguments about the development and production of unconventional resources have been recently heated up.This work introduced the fullblown aspects of unconventional resources especially shale reservoirs,by discussing their concepts and definitions,reviewing the shale gas and shale oil development history and necessity,analyzing the shale plays＇ geology and petroleum systems with respects to key hydrocarbon accumulation elements and mechanisms,and summarizing the technology resolution.This study also discussed the relevant key issues,including significant estimation uncertainty of technically recoverable resources,the equivocal understanding of complex geology preventing the production and technologies implementation optimization,the difficulties of experiences and technologies global expanding,and the corresponding risks and uncertainties.In addition,based on the latest production and exploration data,the future perspective of the unconventional resources was depicted from global unconventional resources assessments,technology development,and limitations constraining the development.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education (No.20130132110023)by the National Natural Science Foundation of China (Nos.41230318,41074077)
文摘A velocity model is an important factor influencing microseismic event locations. We re- view the velocity modeling and inversion techniques for locating microseismic events in exploration for unconventional oil and gas reservoirs. We first describe the geological and geophysical characteristics of reservoir formations related to hydraulic fracturing in heterogeneity, anisotropy, and variability, then discuss the influences of velocity estimation, anisotropy model, and their time-lapse changes on the accuracy in determining microseismic event locations, and then survey some typical methods for building velocity models in locating event locations. We conclude that the three tangled physical attributes of reservoirs make microseismic monitoring very challenging. The uncertainties in velocity model and ignoring its anisotropies and its variations in hydraulic fracturing can cause systematic mislocations of microseismie events which are unacceptable in microseismic monitoring. So, we propose some potential ways for building accurate velocity models.
基金supported by the NSF (DMR-1006194 and CMMI1100339)NSFC (10972189 and 11102175)NSC(100-2628-E-002-034-MY3)
文摘Transforming materials with evolving microstructures is one of the most important classes of smart materials that have many potential technological applications, and an unconventional phase field approach based on the characteristic functions of transforming variants has been developed to simulate the formation and evolution of their microstructures. This approach is advantageous in its explicit material symmetry and energy well structure, minimal number of ma- terial coefficients, and easiness in coupling multiple physical processes and order parameters, and has been applied successfully to study the microstructures and macroscopic prop- erties of shape memory alloys, ferroelectrics, ferromagnetic shape memory alloys, and multiferroic magnetoelectric crys- tals and films with increased complexity. In this topical re- view, the formulation of this unconventional phase field approach will be introduced in details, and its applications to various transforming materials will be discussed. Some ex- amples of specific microstructures will also be presented.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41807296 and No. 41802006)Natural science found for universities of Anhui province (Grant No. KJ2017A036)
文摘Downhole microseismic data has the significant advantages of high signal-to-noise ratio and well-developed P and S waves and the core component of microseismic monitoring is microseismic event location associated with hydraulic fracturing in a relatively high confidence level and accuracy.In this study,we present a multidimensional DIRECT inversion method for microseismic locations and applicability tests over modeling data based on a downhole microseismic monitoring system.Synthetic tests inidcate that the objective function of locations can be defined as a multi-dimensional matrix space by employing the global optimization DIRECT algorithm,because it can be run without the initial value and objective function derivation,and the discretely scattered objective points lead to an expeditious contraction of objective functions in each dimension.This study shows that the DIRECT algorithm can be extensively applied in real downhole microseismic monitoring data from hydraulic fracturing completions.Therefore,the methodology,based on a multidimensional DIRECT algorithm,can provide significant high accuracy and convergent efficiency as well as robust computation for interpretable spatiotemporal microseismic evolution,which is more suitable for real-time processing of a large amount of downhole microseismic monitoring data.
基金by the National Natural Science Foundation of China(No.U19B6003-02)the National Basic Research Program(973)of China(No.2011CB201100).
文摘The discovery of unconventional hydrocarbon resources since the late 20th century changed geologists’understanding of hydrocarbon migration and accumulations and provides a solution to energy shortage.In 2016,unconventional oil production in the USA accounted for 41%of the total oil production;and unconventional natural gas production in China accounted for 35%of total gas production,showing strong growth momentum of unconventional hydrocarbons explorations.Unconventional hydrocarbons generally coexist with conventional petroleum resources;they sometimes distribute in a separate system,not coexisting with a conventional system.Identification and prediction of unconventional resources and their potentials are prominent challenges for geologists.This study analyzed the results of 12,237 drilling wells in six representative petroliferous basins in China and studied the correlations and differences between conventional and unconventional hydrocarbons by comparing their geological features.Migration and accumulation of conventional hydrocarbon are caused dominantly by buoyance.Wepropose a concept of buoyance-driven hydrocarbon accumulation depth to describe the deepest hydrocarbon accumulation depth driven dominantly by buoyance;beyond this depth the buoyance becomes unimportant for hydrocarbon accumulation.We found that the buoyance-driven hydrocarbon accumulation depth in petroliferous basins controls the different oil/gas reservoirs distribution and resource potentials.Hydrocarbon migration and accumulations above this depth is dominated by buoyancy,forming conventional reservoirs in traps with high porosity and permeability,while hydrocarbon migration and accumulation below this depth is dominated by non-buoyancy forces(mainly refers to capillary force,hydrocarbon volumeexpansion force,etc.),forming unconventional reservoirs in tight layers.The buoyance-driven hydrocarbon accumulation depths in six basins in China range from 1200mto 4200 m,which become shallowerwith increasing geothermal gradient,decreasing particle size of sandstone reservoir layers,or an uplift in the whole petroliferous basin.The predicted unconventional resource potential belowthe buoyance-driven hydrocarbon accumulation depth in six basins in China is more than 15.71×10^(9) t oil equivalent,among them 4.71×10^(9) t reserves have been proved.Worldwide,94%of 52,926 oil and gas reservoirs in 1186 basins are conventional reservoirs and only 6%of them are unconventional reservoirs.These 94%conventional reservoirs show promising exploration prospects in the deep area below buoyance-driven hydrocarbon accumulation depth.
基金This work was supported by the major science and technology projects of CNPC during the“14th five-year plan”(Grant number 2021DJ0101)。
文摘The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.
基金National Natural Science Foundation of China(Grant No.10872094)
文摘A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes and Euler equations based on a moving-embedded grid system and adaptive grid methodology.A combination of the third-order upwind scheme and flux-difference splitting scheme,instead of the second-order center-difference scheme which may cause larger wake dissipation,has been employed in the present computational fluid dynamics(CFD)method.The sound pressure data in the near field can be calculated directly by solving the Navier–Stokes equations,and the sound propagation can be predicted by the Kirchhoff method.A harmonic expansion approach is presented for rotor far-field noise prediction,which gives an analytical expression for the integral function in the Kirchhoff formula.As a result,the interpolation process is simplified and the efficiency and accuracy of the interpolation are improved.Then,the high-speed impulsive(HIS)noise of a helicopter rotor at different tip Mach numbers and on different observers is calculated and analyzed in hover and forward flight,which shows a highly directional characteristic of the rotor HIS noise with a maximum value in the rotor plane,and the HSI noise weakens rapidly with the increasing of the directivity angle.In order to investigate the effects of the rotor blade-tip shape on its aeroacoustic characteristics,four kinds of blade tips are designed and their noise characteristics have been simulated.At last,a new unconventional CLOR-II blade tip has been designed,and the noise characteristics of the presented CLOR-II model rotor have been simulated and measured compared to the reference rotors with a rectangular or swept-back platform blade tip.The results demonstrate that the unconventional CLOR-II blade tip can significantly reduce the HSI noise of a rotor.
基金supported by the National Natural Science Foundation of China Youth Science Fund Project(52004297)China Postdoctoral Innovative Talent Support Program(BX20200384)。
文摘The efficient exploration and development of unconventional oil and gas are critical for increasing the self-sufficiency of oil and gas supplies in China.However,such operations continue to face serious problems(e.g.,borehole collapse,loss,and high friction),and associated formation damage can severely impact well completion rates,increase costs,and reduce efficiencies.Water-based drilling fluids possess certain advantages over oil-based drilling fluids(OBDFs)and may offer lasting solutions to resolve the aforementioned issues.However,a significant breakthrough with this material has not yet been made,and major technical problems continue to hinder the economic and large-scale development of unconventional oil and gas.Here,the international frontier external method,which only improves drilling fluid inhibition and lubricity,is expanded into an internal-external technique that improves the overall wellbore quality during drilling.Bionic technologies are introduced into the chemical material synthesis process to imitate the activity of life.A novel drilling and completion fluid technique was developed to improve wellbore quality during drilling and safeguard formation integrity.Macroscopic and microscopic analyses indicated that in terms of wellbore stability,lubricity,and formation protection,this approach could outperform methods that use typical OBDFs.The proposed method also achieves a classification upgrade from environmentally protective drilling fluid to an ecologically friendly drilling fluid.The developed technology was verified in more than 1000 unconventional oil and gas wells in China,and the results indicate significant alleviation of the formation damage attributed to borehole collapse,loss,and high friction.It has been recognized as an effective core technology for exploiting unconventional oil and gas resources.This study introduces a novel research direction for formation protection technology and demonstrates that observations and learning from the natural world can provide an inexhaustible source of ideas and inspire the creation of original materials,technologies,and theories for petroleum engineering.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U22A20166,51904190,12172230 and U19A2098)the Department of Science and Technology of Guangdong Province(No.2019ZT08G315)。
文摘The presence of sealed or semi-sealed,multiscale natural fracture systems appears to be crucial for the successful stimulation of deep reservoirs.To explore the reaction of such systems to reservoir stimulation,a new numerical simulation approach for hydraulic stimulation has been developed,trying to establish a realistic model of the physics involved.Our new model successfully reproduces dynamic fracture activation,network generation,and overall reservoir permeability enhancement.Its outputs indicate that natural fractures facilitate stimulation far beyond the near-wellbore area,and can significantly improve the hydraulic conductivity of unconventional geo-energy reservoirs.According to our model,the fracture activation patterns are jointly determined by the occurrence of natural fractures and the in situ stress.High-density natural fractures,high-fluid pressure,and low effective stress environments promote the formation of complex fracture networks during stimulation.Multistage or multicluster fracturing treatments with an appropriate spacing also increase the stimulated reservoir area(SRA).The simulation scheme demonstrated in this work offers the possibility to elucidate the complex multiphysical couplings seen in the field through detailed site-specific modeling.
