In hospitals,a medical computed tomography(CT)scan is used to detect damage to infected areas of the human body.Using this technology,scientists and engineers have found a way to detect the internal pore connections a...In hospitals,a medical computed tomography(CT)scan is used to detect damage to infected areas of the human body.Using this technology,scientists and engineers have found a way to detect the internal pore connections and characterize rock samples of oil and gas reservoirs in the petroleum industry.Nowadays,the micro-CT scan technique is gaining considerable interest in reservoir rock characterization and in situ monitoring of fluid flow through porous media during different flooding experiments.Along with this digital rock physics(DRP)idea,images have been used to accurately describe and model for simulations of rock samples.In this review,the application of micro-CT and medical-CT scanning in the oil and gas industry has been thoroughly discussed.Recent improvements in DRP and modern imaging techniques in the oil and gas industry have been modeled using both experimental and simulation work.The combination of a DRP study and a CT scan has also been discussed as a unique idea for the current scenario of research work in this field.The available literature shows that the modern imaging technique and the DRP concept can enable an understanding of the pore network model.It has also been observed that the visualization of fluid flow behavior through porous media is now possible during fluid movement through the core samples.This review contributes to the new research area and aids those in this field in quickly gaining an understanding of applied image techniques in the oil and gas industry.展开更多
The transitional zone between the Sub-Himalaya and the Lesser Himalaya is delineated by the Main Boundary Thrust(MBT)to the north and the Himalayan Frontal Thrust(HFT)to the south.The MBT acts as a major topographic b...The transitional zone between the Sub-Himalaya and the Lesser Himalaya is delineated by the Main Boundary Thrust(MBT)to the north and the Himalayan Frontal Thrust(HFT)to the south.The MBT acts as a major topographic barrier that exerts significant control over longitudinal river valleys and sediment dispersal patterns.This region exhibits pronounced fluvial responses shaped by the interplay of tectonic activity and climatic processes.The present study addresses the need for detailed micro-scale morphometric analysis in this zone to better understand ongoing landscape deformation and neotectonic signatures.A multidisciplinary approach integrating geospatial morphometric techniques with field-based evidence has been employed to investigate terrain evolution.Quantitative morphometric assessments were conducted for 16 sub-basins within an active segment of the MBT,bounded by the Jakhan River to the east and the Giri River to the west.Dimensional changes driven by tectonic uplift and accelerated erosion/incision were evaluated using the hypsometric integral(HI),with most values falling below 0.50,indicating that the drainage basins are in an equilibrium stage.Basin shape(Bs)values range from 0.88 to 6.79,supporting the occurrence of accelerated erosional processes.The stream length gradient index(SL)exhibits values between 86 and 816,suggesting rapid uplift and incision.Similarly,computed values of the Chi(χ)coefficient(479-3706)and the steepness index(Ksn;63-214)reflect differential erosion and strong tectonic control on drainage network evolution.The spatial distribution of tectonic deformation was statistically evaluated using a correlation matrix based on the Relative Index of Active Tectonics(RIAT).The results reveal that approximately 50.33%and 16.25%of the study area fall into high and moderate activity zones,respectively,which is corroborated by historical earthquake records and geomorphic evidence.Neotectonic signatures are preserved in the landscape as river terraces,displaced or tilted strata,V-shaped valleys,river offsets,knickpoints,hanging valleys,and channel migration along the strike of the MBT.These findings underscore the significant role of neotectonics in landform evolution and offer valuable insights for geohazard assessment and mitigation strategies in the rapidly developing foothill regions of the Himalaya.展开更多
An electrocoagulation treatment process was developed for treatment and upgrade of petroleum refinery effluent （wastewater）, instead of the conventional methods, which can consume higher amounts of chemicals and pro...An electrocoagulation treatment process was developed for treatment and upgrade of petroleum refinery effluent （wastewater）, instead of the conventional methods, which can consume higher amounts of chemicals and produce larger amounts of sludge. The effect of the operation parameters, such as current density, initial pH, anode material, anode dissolution, energy consumption and electrolysis time, on treatment efficiency was investigated. The experimental results showed that the effluent can be effectively treated under optimal conditions. Fourier transform infrared （FTIR） analysis of the effluent, and scanning electron microscopy （SEM） coupled with energy dispersive analysis of X-rays （EDAX） of the sludge produced, revealed that the unwanted pollutants can be eliminated. The electrocoagulation treatment process was assessed by using the removal efficiency of chemical oxygen demand （COD）, total suspended solids （TSS）, and the general physicochemical characteristics of wastewater, and the results showed that the electrocoagulation is an efficient process for recycling of petroleum wastewater; it is faster and provides better quality of treated water than the conventional methods.展开更多
The utilization of liquefied petroleum gas (LPG) as an alternative automobile fuel in Nigeria was studied, focusing on varying different blend ratios of propane and butane as an alternative fuel in a single-cylinder, ...The utilization of liquefied petroleum gas (LPG) as an alternative automobile fuel in Nigeria was studied, focusing on varying different blend ratios of propane and butane as an alternative fuel in a single-cylinder, four-stroke, and spark ignition (SI) engine. Ricardo WAVE, 1-Dimensional engine simulator was used to model the internal combustion engine where the different blend ratios of propane and butane (P100, P90B10, P80B20, P70B30, P60B40 and P50B50) were tested and compared with a gasoline engine operating under same conditions. From the simulation results for the different LPG blends, there was no significant difference in the engine performance and emissions, but when compared with pure gasoline, it was observed that the LPG showed improved engine performance and lower emissions. The engine power output in using the blends was 25% higher compared to using gasoline;CO emission was 50% less, UHC was 20% less while NO<sub>x</sub> at low speed was significantly lower.展开更多
Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locat...Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.展开更多
In the design of building structures,joint efforts must be decided to resolve the depth of competent layers across the intended site to safeguard the durability of civil engineering structures and to avert the disastr...In the design of building structures,joint efforts must be decided to resolve the depth of competent layers across the intended site to safeguard the durability of civil engineering structures and to avert the disastrous consequences of structural failure and collapse.In this study,an integrated methodology that employed DC resistivity tomography involving 2-D and 3-D techniques and geotechnical-soil analysis was used to evaluate subsoil conditions for engineering site investigation at Okerenkoko primary school,in the Warri-southwest area of Delta State,to adduce the phenomena responsible for the visible cracks/structural failure observed in the buildings.The results obtained brought to light the geological structure beneath the subsurface,which consists of four geoelectric layers identified as topsoil,dry/lithified upper sandy layer,wet sand(water-saturated)and peat/clay/sandy clayey soil(highly water-saturated).The deeply-seated peat/clay materials(ρ≤20Ωm)were delineated in the study area to the depths of 17.1 m and 19.8 m from 2-D and 3-D tomography respectively.3-D images presented as horizontal depth slices revealed the dominance of very low resistivity materials i.e.peat/clay/sandy clay within the fourth,fifth and sixth layers at depths ranging from 8.68-12.5 m,12.5-16.9 m and 16.9-21.9 m respectively.The dominance of mechanically unstable peat/clay/sandy clay layers beneath the subsurface,which are highly mobile in response to volumetric changes,is responsible for the noticeable cracks/failure detected on structures within the study site.These observations were validated by a geotechnical test of soil samples in the study area.Atterberg’s limits of the samples revealed plasticity indices of zero.Thus,the soil samples within the depth analyzed were representatives of sandy soil that does not possess any plasticity.The methods justifiably provided relevant information on the subsurface geology beneath the study site and should be appropriated as major tools for engineering site assessment/geotechnical projects.展开更多
1.Introduction Climate change mitigation pathways aimed at limiting global anthropogenic carbon dioxide(CO_(2))emissions while striving to constrain the global temperature increase to below 2℃—as outlined by the Int...1.Introduction Climate change mitigation pathways aimed at limiting global anthropogenic carbon dioxide(CO_(2))emissions while striving to constrain the global temperature increase to below 2℃—as outlined by the Intergovernmental Panel on Climate Change(IPCC)—consistently predict the widespread implementation of CO_(2)geological storage on a global scale.展开更多
Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the inte...Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.展开更多
This study investigates the mineralogy and mineral-chemistry of a newly discovered Au-Ag-Bi-Te mineralization at the Aydindere Fe-Cu skarn deposit,within the Pontides Tectonic Unit,northeastern Turkey.The mineralizati...This study investigates the mineralogy and mineral-chemistry of a newly discovered Au-Ag-Bi-Te mineralization at the Aydindere Fe-Cu skarn deposit,within the Pontides Tectonic Unit,northeastern Turkey.The mineralization is developed in the skarn zone at the contact between Upper Cretaceous andesite-pyroclastic rocks and a Paleocene–Eocene I-type granitoid.The principal ore minerals of the Aydindere Fe-Cu deposit are oxides(magnetite),sulfides(pyrite-chalcopyritegalena-sphalerite),tellurides/sulfotellurides(tetradymite,hessite),sulfosalts(wittichenite,emplectite,aikinite) and native gold-electrum.Skarn minerals include anhydrous phases(garnet) formed in a prograde stage and hydrous phases(amphibole,epidote,chlorite),which were formed in a retrograde stage in association with quartz,adularia,apatite and late calcite.Sulfides,tellurides and sulfosalts are introduced during the retrograde stage.The Au-Ag-Bi-Te mineralization was detected for the first time within the western ore body of the Aydindere deposit,and occurs in calcite-bearing sulfide bodies that cut magnetite-garnet-amphibole-epidote skarns with magnetite ores of different grade,including massive magnetite.Chlorite geothermometry indicates formation of the Au-Ag-BiTe mineralization at temperatures between 300 and 250 ℃,during the retrograde skarn evolution.Assuming the temperature is ~275 ℃,logfS_(2) =-10.5 to-13,logfO_(2) =-37 to-33,and logf Te2 values range from approximately-12 to-8.5 were estimated.The available mineralogical and geological data(presences of magnetite,oxidized-type tellurides/sulfotellurides,and andraditic garnets,and absence of pyrrhotite and arsenopyrite) suggest that Aydindere is an oxidized Au-bearing skarn deposit.The discovery of Au-Ag-Bi-Te mineralization at Aydindere increases its productivity and requires more detailed exploration in the deposit for precious(Au,Ag) and critical(Bi,Te) metals.展开更多
Size reduction of the gas turbines(GT)by reducing the inlet S-shaped diffuser length increases the powerto-weight ratio.It improves the techno-economic features of the GT by lesser fuel consumption.However,this Length...Size reduction of the gas turbines(GT)by reducing the inlet S-shaped diffuser length increases the powerto-weight ratio.It improves the techno-economic features of the GT by lesser fuel consumption.However,this Length reduction of a bare S-shaped diffuser to an aggressive S-shaped diffuser would risk flow separation and performance reduction of the diffuser and the air intake of the GT.The objective of this research is to propose and assess fitted energy promoters(EPs)to enhance the S-shaped diffuser performance by controlling and modifying the flow in the high bending zone of the diffuser.After experimental assessment,the work has been extended to cover more cases by numerical investigations on bare,bare aggressive,and aggressive with energy promoters S-shaped diffusers.Three types of EPs,namely co-rotating low-profile,co-rotating streamline sheet,and trapezoidal submerged EPs were tested with various combinations over a range of Reynolds numbers from 40,000 to 75,000.The respective S-shaped diffusers were simulated by computational fluid dynamics(CFD)using ANSYS software adopting a steady,3D,standard k-εturbulence model to acquire the details of the flow structure,which cannot be visualized in the experiment.The diffuser performance has been evaluated by the performance indicators of static pressure recovery coefficient,total pressure loss coefficient,and distortion coefficient(DC(45°)).The enhancements in the static pressure recovery of the S-shaped aggressive diffuser with energy promoters are 19.5%,22.2%,and 24.5%with EPs at planes 3,4 and 5,respectively,compared to the aggressive bare diffuser.In addition,the installation of the EPs resulted in a DC(45°)reduction at the outlet plane of the diffuser of about 43%at Re=40,000.The enhancements in the performance parameters confirm that aggravating the internal flow eliminates the flow separation and enhances the GT intake efficiency.展开更多
High-water-cut mature reservoirs typically serve as the“ballast”for ensuring China’s annual crude oil production of 200 million tons.Despite the use of water flooding and chemical methods,over 40%of crude oil remai...High-water-cut mature reservoirs typically serve as the“ballast”for ensuring China’s annual crude oil production of 200 million tons.Despite the use of water flooding and chemical methods,over 40%of crude oil remains unexploited.It is critical to develop efficient revolutionary technologies to further enhance oil recovery(EOR)by a large percentage in high-water-cut mature reservoirs.To address this issue,the potential of vertical remaining oil in Daqing Oilfield is first analyzed from massive monitoring data.Using molecular dynamics simulation to design optimal synthetic routine,a copolymer without flu-orine or silicon is synthesized by modifying vinyl acetate(VAc)with maleic anhydride(MA)and styrene(St),and treated as a supercritical CO_(2)(scCO_(2))thickener.The underlying EOR mechanism of the scCO_(2) thickener is thereafter clarified by high-temperature,high-pressure oil displacement experiments.The EOR effect by thickened scCO_(2) flooding in a typical high-water-cut mature reservoir is predicted,and future technological advancements of the technique are ultimately discussed.Results show that the ver-tical remaining oil enriched in weakly swept zones is a primary target for further EOR in high-water-cut mature reservoirs.The copolymer typically exhibits good solubility,strong dispersion stability,and high thickening effect in scCO_(2).Under an ambient pressure of 10 MPa and a temperature of 50℃,the disso-lution of copolymer at a mass concentration of 0.2%can effectively increase the viscosity of scCO_(2) by 39.4 times.Due to the synergistic effect between expanding vertical swept volume and inhibiting gas channel-ing,crude oil recovery can be further enhanced by 23.1%for a typical high-water-cut mature reservoir when the scCO_(2) viscosity is increased by 50 times.Our understandings demonstrate that the thickened scCO_(2) flooding technology has significant technical advantages in high-water-cut mature reservoirs,with challenges and future development directions in field-scale applications also highlighted.展开更多
Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However...Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.展开更多
Carbon capture,utilization,and storage(CCUS)represents a critical technological pathway for global car-bon emission reduction.CCUS-enhanced oil recovery(EOR)technology is the most feasible CCUS technol-ogy demonstrati...Carbon capture,utilization,and storage(CCUS)represents a critical technological pathway for global car-bon emission reduction.CCUS-enhanced oil recovery(EOR)technology is the most feasible CCUS technol-ogy demonstrating dual benefits of enhanced energy production and carbon reduction.This study comprehensively described the key influencing factors governing CO_(2)-EOR and geological storage and systematically analyzed reservoir properties,fluid characteristics,and operational parameters.The mech-anisms of these parameters on EOR versus CO_(2) storage performance were investigated throughout CCUS-EOR processes.This paper proposes a coupled two-stage CCUS-EOR process:CO_(2)-EOR storage stage and long-term CO_(2) storage stage after the CO_(2) injection phase is completed.In each stage,the main control factors impacting the CO_(2)-EOR and storage stages are screened and coupled with rigorous technical anal-ysis.The key factors here are reservoir properties,fluid characteristics,and operational parameter.A novel CCUS-EOR synergistic method was proposed to optimize the lifecycle performance of dual objective of EOR and storage.Furthermore,based on multi-objective optimization,considering the lifecycle,a multi-scale techno-economic evaluation method was proposed to fully assess the CCUS-EOR project per-formance.Finally,a set of recommendations for advancing CCUS-EOR technologies by deploying multi-factor/multi-field coupling methodologies,novel green intelligent injection materials,and artificial intel-ligence/machine learning technologies were visited.展开更多
Fluid imbibition from hydraulic fractures into shale formations is mainly affected by a combination of capillary forces and viscous resistance,both of which are closely related to the pore geometry.This study establis...Fluid imbibition from hydraulic fractures into shale formations is mainly affected by a combination of capillary forces and viscous resistance,both of which are closely related to the pore geometry.This study established five self-imbibition models with idealized pore structures and conducted a comparative analysis of these models.These models include circular,square,and equilateral triangular capillaries;a triangular star-shaped cross-section formed by three tangent spherical particles;and a traditional porous medium representation method.All these models are derived based on Newton’s second law,where capillary pressure is described by the Young-Laplace equation and viscous resistance is characterized by the Hagen-Poiret equation and Darcy’s law.All derived models predict that the fluid imbibition distance is proportional to the square root of time,in accordance with the classical Lucas-Washburn law.However,different pore structures exhibit significantly different characteristic imbibition rates.Compared to the single pore model,the conventional Darcy’s law-based model for porous media predicts significantly lower imbibition rates,which is consistent with the relatively slower uptake rates in actual shale nanoscale pore networks.These findings emphasize the important role played by pore geometry in fluid imbibition dynamics and further point to the need for optimizing pore structure to extend fluid imbibition duration in shale reservoirs in practical operations.展开更多
In-situ conversion of subsurface hydrocarbons via electromagnetic(EM)heating has emerged as a promising technology for producing carbon-zero and affordable hydrogen(H_(2))directly from natural gas reservoirs.However,t...In-situ conversion of subsurface hydrocarbons via electromagnetic(EM)heating has emerged as a promising technology for producing carbon-zero and affordable hydrogen(H_(2))directly from natural gas reservoirs.However,the reaction pathways and role of water as an additional hydrogen donor in EM-assisted methane-to-hydrogen(CH_(4)-to-H_(2))conversion are poorly understood.Herein,we employ a combination of lab-scale EM-heating experiments and reaction modeling analyses to unravel reaction pathways and elucidate water's role in enhancing hydrogen production.The labelled hydrogen isotope of deuterium oxide(D_(2)O)is used to trace the sources of hydrogen.The results show that water significantly boosts hydrogen yield via coke gasification at around 400℃and steam methane reforming(SMR)reaction at over 600℃in the presence of sandstone.Water-gas shift reaction exhibits a minor impact on this enhancement.Reaction mechanism analyses reveal that the involvement of water can initiate auto-catalytic loop reactions with methane,which not only generates extra hydrogen but also produces OH radicals that enhance the reactants'reactivity.This work provides crucial insights into the reaction mechanisms involved in water-carbon-methane interactions and underscores water's potential as a hydrogen donor for in-situ hydrogen production from natural gas reservoirs.It also addresses the challenges related to carbon deposition and in-situ catalyst regeneration during EM heating,thus derisking this technology and laying a foundation for future pilots.展开更多
Shale gas,a type of unconventional natural gas found within shale formations,has emerged as a significant source of energy globally.The West Bokaro Basin,part of the Damodar Valley,is known for its rich coal deposits ...Shale gas,a type of unconventional natural gas found within shale formations,has emerged as a significant source of energy globally.The West Bokaro Basin,part of the Damodar Valley,is known for its rich coal deposits and complex geological history.The basin's stratigraphy includes significant coal-bearing formations interbedded with shales,which may be potential sources of shale gas.The key formations in the basin include the Barakar Formation,which is the primary coal-bearing unit,and the Raniganj Formation,which contains substantial shale intervals.These formations exhibit varying thicknesses,organic content,thermal maturity,and mechanical strength,all of which are critical factors influencing shale gas potential.The assessment of shale gas potential in the West Bokaro Basin involves evaluating the organic richness,thermal maturity,pore characteristics,geochemistry,and mineralogy of the shale formations.Apart from organic richness and thermal maturity,the shale formations must be friable,as they generally lack natural permeability.This study aims to present a comprehensive analysis of the prospects of shale gas in the West Bokaro Basin based on the organic petrography,geochemistry,mineralogical study,Fourier Transform Infrared Spectroscopy(FTIR)analysis,and low-pressure N_(2) adsorption analysis.The dark color,greasy touch,and high total organic carbon(TOC)content(5.88%-22.84%)provided an initial clue for the shale's potential as a source rock.Results from organic petrographic analysis suggest that these shales contain kerogen type Ⅲ,which is a known indicator of gas-prone zones.The random vitrinite reflectance(R_(o),0.80%-0.91%)and the temperature of maximum pyrolysis yield(Tmax,434-448℃)indicate that the organic matter has attained the sufficient thermal maturity required for the generation of hydrocarbons.FTIR and X-ray diffraction(XRD)analyses identified inorganic entities and high quartz content in the shale samples,confirming their friability.The brittleness index(BI)calculated using X-ray fluorescence(XRF)data showed BI values above 0.48,indicating that the shales are brittle,which is advantageous for hydraulic fracturing.The high quartz content in the shale might act as a natural proppant,enhancing gas extraction efficiency.These findings suggest that the West Bokaro shales hold promise for economically viable shale gas production.展开更多
The stability of acid-crude oil emulsion poses manifold issues in the oil industry.Experimentally evaluating this phenomenon may be costly and time-consuming.In contrast,machine learning models have proven effective i...The stability of acid-crude oil emulsion poses manifold issues in the oil industry.Experimentally evaluating this phenomenon may be costly and time-consuming.In contrast,machine learning models have proven effective in predicting and evaluating various phenomena.This research is the first of its kind to assess the stability of acid-crude oil emulsion,employing various classification machine learning models.For this purpose,a data set consisting of 249 experimental data points belonging to 11 different crude oil samples was collected.Three tree-based models,namely decision tree(DT),random forest(RF),and categorical boosting(CatBoost),as well as three artificial neural network models,namely radial basis function(RBF),multi-layer perceptron(MLP) and convolutional neural network(CNN),were developed based on the properties of crude oil,acid,and protective additive.The CatBoost model obtained the highest accuracy with 0.9687,followed closely by the CNN model with 0.9673.In addition,confusion matrix findings showed the superiority of the CatBoost model.Finally,by applying the SHapley Additive exPlanations(SHAP) method to analyze the impact of input parameters,it was found that the crude oil viscosity has the most significant effect on the model's output with the mean absolute SHAP value of 0.88.展开更多
Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Br...Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Breakdown pressure is a vital component in hydraulic fracture job design,which is affected by various parameters including rock strength and depth.Various methods including modelling and experimental approaches exist to quantify the breakdown pressure.There have been many strategies to reduce this pressure for efficient and economical hydraulic fracture jobs,especially when this pressure exceeds pump capacity.This study provides a detailed review of breakdown pressure in terms of fundamentals,influencing factors,and estimation approaches.In addition,different strategies are also presented to reduce the breakdown pressure along with cost analysis.Lastly,research gaps pertinent to this area are highlighted for emphasis in future research.Specifically,it has been found that high breakdown pressure is associated with challenges,but there are no comprehensive techniques and strategies to lower this pressure in formations with very high in situ stress profiles or complicated tectonic settings.Developing such methods is important to minimize operational failures,lower costs and reduce the environmental risks during reservoir exploitation.This study reviews the fundamentals,influencing factors,and estimation methods of breakdown pressure and provides a deep understanding of the strategies for its reduction.The study also presents the cost analyses,and highlights research gaps for future investigation.展开更多
An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-h...An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-hydromechanical(THM)coupled simulations were conducted using the TOUGH + FLAC3D simulator to predict the THM behaviors of a generic nuclear waste repository over 100,000 years following closure.The designed engineered barrier system(EBS)consists of the waste canister,backfill,and concrete liner.The objective of this study is to evaluate the long-term performance of the repository in the presence of continued hydrogen(H_(2))and heat release around the canister.The simulation results show that thermal pressurization and gas accumulation significantly raise the pore pressure within the EBS and surrounding host rock,while the peak pore pressure is not likely to exceed the lithostatic stress so that there is no risk of widespread hydro-fracturing in the host rock.However,tension failure and fracturing can occur at the tunnel scale because of internal gas buildup.Meanwhile,the generated H_(2) continuously migrates outward and tends to accumulate in the concrete liner and excavation disturbed zone surrounding the tunnel because of lower capillary pressure.Nevertheless,the fluids that may contain radionuclides will not leach into the confining units over a 100,000-year time frame.Our analysis indicates that for the assumed disposal system in Opalinus Clay,the generated heat and gas can gradually be transported through the host rock without significantly disturbing the isolation characteristics of the repository.展开更多
文摘In hospitals,a medical computed tomography(CT)scan is used to detect damage to infected areas of the human body.Using this technology,scientists and engineers have found a way to detect the internal pore connections and characterize rock samples of oil and gas reservoirs in the petroleum industry.Nowadays,the micro-CT scan technique is gaining considerable interest in reservoir rock characterization and in situ monitoring of fluid flow through porous media during different flooding experiments.Along with this digital rock physics(DRP)idea,images have been used to accurately describe and model for simulations of rock samples.In this review,the application of micro-CT and medical-CT scanning in the oil and gas industry has been thoroughly discussed.Recent improvements in DRP and modern imaging techniques in the oil and gas industry have been modeled using both experimental and simulation work.The combination of a DRP study and a CT scan has also been discussed as a unique idea for the current scenario of research work in this field.The available literature shows that the modern imaging technique and the DRP concept can enable an understanding of the pore network model.It has also been observed that the visualization of fluid flow behavior through porous media is now possible during fluid movement through the core samples.This review contributes to the new research area and aids those in this field in quickly gaining an understanding of applied image techniques in the oil and gas industry.
基金Department of Petroleum Engineering and Earth Sciences,UPES,for supporting this researchR&D,UPES,for providing a PhD scholarship and contingency to support geological fieldworkDST-ANRF Grant no CRG/2023/000555 for partial financial support for this research.
文摘The transitional zone between the Sub-Himalaya and the Lesser Himalaya is delineated by the Main Boundary Thrust(MBT)to the north and the Himalayan Frontal Thrust(HFT)to the south.The MBT acts as a major topographic barrier that exerts significant control over longitudinal river valleys and sediment dispersal patterns.This region exhibits pronounced fluvial responses shaped by the interplay of tectonic activity and climatic processes.The present study addresses the need for detailed micro-scale morphometric analysis in this zone to better understand ongoing landscape deformation and neotectonic signatures.A multidisciplinary approach integrating geospatial morphometric techniques with field-based evidence has been employed to investigate terrain evolution.Quantitative morphometric assessments were conducted for 16 sub-basins within an active segment of the MBT,bounded by the Jakhan River to the east and the Giri River to the west.Dimensional changes driven by tectonic uplift and accelerated erosion/incision were evaluated using the hypsometric integral(HI),with most values falling below 0.50,indicating that the drainage basins are in an equilibrium stage.Basin shape(Bs)values range from 0.88 to 6.79,supporting the occurrence of accelerated erosional processes.The stream length gradient index(SL)exhibits values between 86 and 816,suggesting rapid uplift and incision.Similarly,computed values of the Chi(χ)coefficient(479-3706)and the steepness index(Ksn;63-214)reflect differential erosion and strong tectonic control on drainage network evolution.The spatial distribution of tectonic deformation was statistically evaluated using a correlation matrix based on the Relative Index of Active Tectonics(RIAT).The results reveal that approximately 50.33%and 16.25%of the study area fall into high and moderate activity zones,respectively,which is corroborated by historical earthquake records and geomorphic evidence.Neotectonic signatures are preserved in the landscape as river terraces,displaced or tilted strata,V-shaped valleys,river offsets,knickpoints,hanging valleys,and channel migration along the strike of the MBT.These findings underscore the significant role of neotectonics in landform evolution and offer valuable insights for geohazard assessment and mitigation strategies in the rapidly developing foothill regions of the Himalaya.
基金the financial support from the Ministry of Higher Education and Scientific Research-Iraq
文摘An electrocoagulation treatment process was developed for treatment and upgrade of petroleum refinery effluent （wastewater）, instead of the conventional methods, which can consume higher amounts of chemicals and produce larger amounts of sludge. The effect of the operation parameters, such as current density, initial pH, anode material, anode dissolution, energy consumption and electrolysis time, on treatment efficiency was investigated. The experimental results showed that the effluent can be effectively treated under optimal conditions. Fourier transform infrared （FTIR） analysis of the effluent, and scanning electron microscopy （SEM） coupled with energy dispersive analysis of X-rays （EDAX） of the sludge produced, revealed that the unwanted pollutants can be eliminated. The electrocoagulation treatment process was assessed by using the removal efficiency of chemical oxygen demand （COD）, total suspended solids （TSS）, and the general physicochemical characteristics of wastewater, and the results showed that the electrocoagulation is an efficient process for recycling of petroleum wastewater; it is faster and provides better quality of treated water than the conventional methods.
文摘The utilization of liquefied petroleum gas (LPG) as an alternative automobile fuel in Nigeria was studied, focusing on varying different blend ratios of propane and butane as an alternative fuel in a single-cylinder, four-stroke, and spark ignition (SI) engine. Ricardo WAVE, 1-Dimensional engine simulator was used to model the internal combustion engine where the different blend ratios of propane and butane (P100, P90B10, P80B20, P70B30, P60B40 and P50B50) were tested and compared with a gasoline engine operating under same conditions. From the simulation results for the different LPG blends, there was no significant difference in the engine performance and emissions, but when compared with pure gasoline, it was observed that the LPG showed improved engine performance and lower emissions. The engine power output in using the blends was 25% higher compared to using gasoline;CO emission was 50% less, UHC was 20% less while NO<sub>x</sub> at low speed was significantly lower.
文摘Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.
文摘In the design of building structures,joint efforts must be decided to resolve the depth of competent layers across the intended site to safeguard the durability of civil engineering structures and to avert the disastrous consequences of structural failure and collapse.In this study,an integrated methodology that employed DC resistivity tomography involving 2-D and 3-D techniques and geotechnical-soil analysis was used to evaluate subsoil conditions for engineering site investigation at Okerenkoko primary school,in the Warri-southwest area of Delta State,to adduce the phenomena responsible for the visible cracks/structural failure observed in the buildings.The results obtained brought to light the geological structure beneath the subsurface,which consists of four geoelectric layers identified as topsoil,dry/lithified upper sandy layer,wet sand(water-saturated)and peat/clay/sandy clayey soil(highly water-saturated).The deeply-seated peat/clay materials(ρ≤20Ωm)were delineated in the study area to the depths of 17.1 m and 19.8 m from 2-D and 3-D tomography respectively.3-D images presented as horizontal depth slices revealed the dominance of very low resistivity materials i.e.peat/clay/sandy clay within the fourth,fifth and sixth layers at depths ranging from 8.68-12.5 m,12.5-16.9 m and 16.9-21.9 m respectively.The dominance of mechanically unstable peat/clay/sandy clay layers beneath the subsurface,which are highly mobile in response to volumetric changes,is responsible for the noticeable cracks/failure detected on structures within the study site.These observations were validated by a geotechnical test of soil samples in the study area.Atterberg’s limits of the samples revealed plasticity indices of zero.Thus,the soil samples within the depth analyzed were representatives of sandy soil that does not possess any plasticity.The methods justifiably provided relevant information on the subsurface geology beneath the study site and should be appropriated as major tools for engineering site assessment/geotechnical projects.
基金supported by the National Key Research and Development Program of China(2022YFE0206700)。
文摘1.Introduction Climate change mitigation pathways aimed at limiting global anthropogenic carbon dioxide(CO_(2))emissions while striving to constrain the global temperature increase to below 2℃—as outlined by the Intergovernmental Panel on Climate Change(IPCC)—consistently predict the widespread implementation of CO_(2)geological storage on a global scale.
基金supported by the Russian Science Foundation(23-29-00830).
文摘Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.
文摘This study investigates the mineralogy and mineral-chemistry of a newly discovered Au-Ag-Bi-Te mineralization at the Aydindere Fe-Cu skarn deposit,within the Pontides Tectonic Unit,northeastern Turkey.The mineralization is developed in the skarn zone at the contact between Upper Cretaceous andesite-pyroclastic rocks and a Paleocene–Eocene I-type granitoid.The principal ore minerals of the Aydindere Fe-Cu deposit are oxides(magnetite),sulfides(pyrite-chalcopyritegalena-sphalerite),tellurides/sulfotellurides(tetradymite,hessite),sulfosalts(wittichenite,emplectite,aikinite) and native gold-electrum.Skarn minerals include anhydrous phases(garnet) formed in a prograde stage and hydrous phases(amphibole,epidote,chlorite),which were formed in a retrograde stage in association with quartz,adularia,apatite and late calcite.Sulfides,tellurides and sulfosalts are introduced during the retrograde stage.The Au-Ag-Bi-Te mineralization was detected for the first time within the western ore body of the Aydindere deposit,and occurs in calcite-bearing sulfide bodies that cut magnetite-garnet-amphibole-epidote skarns with magnetite ores of different grade,including massive magnetite.Chlorite geothermometry indicates formation of the Au-Ag-BiTe mineralization at temperatures between 300 and 250 ℃,during the retrograde skarn evolution.Assuming the temperature is ~275 ℃,logfS_(2) =-10.5 to-13,logfO_(2) =-37 to-33,and logf Te2 values range from approximately-12 to-8.5 were estimated.The available mineralogical and geological data(presences of magnetite,oxidized-type tellurides/sulfotellurides,and andraditic garnets,and absence of pyrrhotite and arsenopyrite) suggest that Aydindere is an oxidized Au-bearing skarn deposit.The discovery of Au-Ag-Bi-Te mineralization at Aydindere increases its productivity and requires more detailed exploration in the deposit for precious(Au,Ag) and critical(Bi,Te) metals.
文摘Size reduction of the gas turbines(GT)by reducing the inlet S-shaped diffuser length increases the powerto-weight ratio.It improves the techno-economic features of the GT by lesser fuel consumption.However,this Length reduction of a bare S-shaped diffuser to an aggressive S-shaped diffuser would risk flow separation and performance reduction of the diffuser and the air intake of the GT.The objective of this research is to propose and assess fitted energy promoters(EPs)to enhance the S-shaped diffuser performance by controlling and modifying the flow in the high bending zone of the diffuser.After experimental assessment,the work has been extended to cover more cases by numerical investigations on bare,bare aggressive,and aggressive with energy promoters S-shaped diffusers.Three types of EPs,namely co-rotating low-profile,co-rotating streamline sheet,and trapezoidal submerged EPs were tested with various combinations over a range of Reynolds numbers from 40,000 to 75,000.The respective S-shaped diffusers were simulated by computational fluid dynamics(CFD)using ANSYS software adopting a steady,3D,standard k-εturbulence model to acquire the details of the flow structure,which cannot be visualized in the experiment.The diffuser performance has been evaluated by the performance indicators of static pressure recovery coefficient,total pressure loss coefficient,and distortion coefficient(DC(45°)).The enhancements in the static pressure recovery of the S-shaped aggressive diffuser with energy promoters are 19.5%,22.2%,and 24.5%with EPs at planes 3,4 and 5,respectively,compared to the aggressive bare diffuser.In addition,the installation of the EPs resulted in a DC(45°)reduction at the outlet plane of the diffuser of about 43%at Re=40,000.The enhancements in the performance parameters confirm that aggravating the internal flow eliminates the flow separation and enhances the GT intake efficiency.
基金the National Natural Science Foundation of China(U22B6005,52174043,52474035)the Beijing Natural Science Foundation(3242019)the China National Petroleum Corporation(CNPC)Innovation Foundation(2022DQ02-0208 and 2024DQ02-0114).
文摘High-water-cut mature reservoirs typically serve as the“ballast”for ensuring China’s annual crude oil production of 200 million tons.Despite the use of water flooding and chemical methods,over 40%of crude oil remains unexploited.It is critical to develop efficient revolutionary technologies to further enhance oil recovery(EOR)by a large percentage in high-water-cut mature reservoirs.To address this issue,the potential of vertical remaining oil in Daqing Oilfield is first analyzed from massive monitoring data.Using molecular dynamics simulation to design optimal synthetic routine,a copolymer without flu-orine or silicon is synthesized by modifying vinyl acetate(VAc)with maleic anhydride(MA)and styrene(St),and treated as a supercritical CO_(2)(scCO_(2))thickener.The underlying EOR mechanism of the scCO_(2) thickener is thereafter clarified by high-temperature,high-pressure oil displacement experiments.The EOR effect by thickened scCO_(2) flooding in a typical high-water-cut mature reservoir is predicted,and future technological advancements of the technique are ultimately discussed.Results show that the ver-tical remaining oil enriched in weakly swept zones is a primary target for further EOR in high-water-cut mature reservoirs.The copolymer typically exhibits good solubility,strong dispersion stability,and high thickening effect in scCO_(2).Under an ambient pressure of 10 MPa and a temperature of 50℃,the disso-lution of copolymer at a mass concentration of 0.2%can effectively increase the viscosity of scCO_(2) by 39.4 times.Due to the synergistic effect between expanding vertical swept volume and inhibiting gas channel-ing,crude oil recovery can be further enhanced by 23.1%for a typical high-water-cut mature reservoir when the scCO_(2) viscosity is increased by 50 times.Our understandings demonstrate that the thickened scCO_(2) flooding technology has significant technical advantages in high-water-cut mature reservoirs,with challenges and future development directions in field-scale applications also highlighted.
基金support from the National Natural:Science Foundation of China(NO.52174014)the National Natural Science Foundation Basic Science Center(NO.52288101).
文摘Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.
基金the financial support from the National Key Research and Development Program of China(2022YFE0206700)the Science Foundation of China University of Petroleum,Beijing(2462021YJRC012).
文摘Carbon capture,utilization,and storage(CCUS)represents a critical technological pathway for global car-bon emission reduction.CCUS-enhanced oil recovery(EOR)technology is the most feasible CCUS technol-ogy demonstrating dual benefits of enhanced energy production and carbon reduction.This study comprehensively described the key influencing factors governing CO_(2)-EOR and geological storage and systematically analyzed reservoir properties,fluid characteristics,and operational parameters.The mech-anisms of these parameters on EOR versus CO_(2) storage performance were investigated throughout CCUS-EOR processes.This paper proposes a coupled two-stage CCUS-EOR process:CO_(2)-EOR storage stage and long-term CO_(2) storage stage after the CO_(2) injection phase is completed.In each stage,the main control factors impacting the CO_(2)-EOR and storage stages are screened and coupled with rigorous technical anal-ysis.The key factors here are reservoir properties,fluid characteristics,and operational parameter.A novel CCUS-EOR synergistic method was proposed to optimize the lifecycle performance of dual objective of EOR and storage.Furthermore,based on multi-objective optimization,considering the lifecycle,a multi-scale techno-economic evaluation method was proposed to fully assess the CCUS-EOR project per-formance.Finally,a set of recommendations for advancing CCUS-EOR technologies by deploying multi-factor/multi-field coupling methodologies,novel green intelligent injection materials,and artificial intel-ligence/machine learning technologies were visited.
文摘Fluid imbibition from hydraulic fractures into shale formations is mainly affected by a combination of capillary forces and viscous resistance,both of which are closely related to the pore geometry.This study established five self-imbibition models with idealized pore structures and conducted a comparative analysis of these models.These models include circular,square,and equilateral triangular capillaries;a triangular star-shaped cross-section formed by three tangent spherical particles;and a traditional porous medium representation method.All these models are derived based on Newton’s second law,where capillary pressure is described by the Young-Laplace equation and viscous resistance is characterized by the Hagen-Poiret equation and Darcy’s law.All derived models predict that the fluid imbibition distance is proportional to the square root of time,in accordance with the classical Lucas-Washburn law.However,different pore structures exhibit significantly different characteristic imbibition rates.Compared to the single pore model,the conventional Darcy’s law-based model for porous media predicts significantly lower imbibition rates,which is consistent with the relatively slower uptake rates in actual shale nanoscale pore networks.These findings emphasize the important role played by pore geometry in fluid imbibition dynamics and further point to the need for optimizing pore structure to extend fluid imbibition duration in shale reservoirs in practical operations.
基金supported by a generous gift from The CH Foundationthe support from the Distinguished Graduate Student Assistantship and the Graduate Research Support Award at Texas Tech University+1 种基金the Aid fund from AAPGthe Matejek Family Faculty Fellowship。
文摘In-situ conversion of subsurface hydrocarbons via electromagnetic(EM)heating has emerged as a promising technology for producing carbon-zero and affordable hydrogen(H_(2))directly from natural gas reservoirs.However,the reaction pathways and role of water as an additional hydrogen donor in EM-assisted methane-to-hydrogen(CH_(4)-to-H_(2))conversion are poorly understood.Herein,we employ a combination of lab-scale EM-heating experiments and reaction modeling analyses to unravel reaction pathways and elucidate water's role in enhancing hydrogen production.The labelled hydrogen isotope of deuterium oxide(D_(2)O)is used to trace the sources of hydrogen.The results show that water significantly boosts hydrogen yield via coke gasification at around 400℃and steam methane reforming(SMR)reaction at over 600℃in the presence of sandstone.Water-gas shift reaction exhibits a minor impact on this enhancement.Reaction mechanism analyses reveal that the involvement of water can initiate auto-catalytic loop reactions with methane,which not only generates extra hydrogen but also produces OH radicals that enhance the reactants'reactivity.This work provides crucial insights into the reaction mechanisms involved in water-carbon-methane interactions and underscores water's potential as a hydrogen donor for in-situ hydrogen production from natural gas reservoirs.It also addresses the challenges related to carbon deposition and in-situ catalyst regeneration during EM heating,thus derisking this technology and laying a foundation for future pilots.
文摘Shale gas,a type of unconventional natural gas found within shale formations,has emerged as a significant source of energy globally.The West Bokaro Basin,part of the Damodar Valley,is known for its rich coal deposits and complex geological history.The basin's stratigraphy includes significant coal-bearing formations interbedded with shales,which may be potential sources of shale gas.The key formations in the basin include the Barakar Formation,which is the primary coal-bearing unit,and the Raniganj Formation,which contains substantial shale intervals.These formations exhibit varying thicknesses,organic content,thermal maturity,and mechanical strength,all of which are critical factors influencing shale gas potential.The assessment of shale gas potential in the West Bokaro Basin involves evaluating the organic richness,thermal maturity,pore characteristics,geochemistry,and mineralogy of the shale formations.Apart from organic richness and thermal maturity,the shale formations must be friable,as they generally lack natural permeability.This study aims to present a comprehensive analysis of the prospects of shale gas in the West Bokaro Basin based on the organic petrography,geochemistry,mineralogical study,Fourier Transform Infrared Spectroscopy(FTIR)analysis,and low-pressure N_(2) adsorption analysis.The dark color,greasy touch,and high total organic carbon(TOC)content(5.88%-22.84%)provided an initial clue for the shale's potential as a source rock.Results from organic petrographic analysis suggest that these shales contain kerogen type Ⅲ,which is a known indicator of gas-prone zones.The random vitrinite reflectance(R_(o),0.80%-0.91%)and the temperature of maximum pyrolysis yield(Tmax,434-448℃)indicate that the organic matter has attained the sufficient thermal maturity required for the generation of hydrocarbons.FTIR and X-ray diffraction(XRD)analyses identified inorganic entities and high quartz content in the shale samples,confirming their friability.The brittleness index(BI)calculated using X-ray fluorescence(XRF)data showed BI values above 0.48,indicating that the shales are brittle,which is advantageous for hydraulic fracturing.The high quartz content in the shale might act as a natural proppant,enhancing gas extraction efficiency.These findings suggest that the West Bokaro shales hold promise for economically viable shale gas production.
文摘The stability of acid-crude oil emulsion poses manifold issues in the oil industry.Experimentally evaluating this phenomenon may be costly and time-consuming.In contrast,machine learning models have proven effective in predicting and evaluating various phenomena.This research is the first of its kind to assess the stability of acid-crude oil emulsion,employing various classification machine learning models.For this purpose,a data set consisting of 249 experimental data points belonging to 11 different crude oil samples was collected.Three tree-based models,namely decision tree(DT),random forest(RF),and categorical boosting(CatBoost),as well as three artificial neural network models,namely radial basis function(RBF),multi-layer perceptron(MLP) and convolutional neural network(CNN),were developed based on the properties of crude oil,acid,and protective additive.The CatBoost model obtained the highest accuracy with 0.9687,followed closely by the CNN model with 0.9673.In addition,confusion matrix findings showed the superiority of the CatBoost model.Finally,by applying the SHapley Additive exPlanations(SHAP) method to analyze the impact of input parameters,it was found that the crude oil viscosity has the most significant effect on the model's output with the mean absolute SHAP value of 0.88.
文摘Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Breakdown pressure is a vital component in hydraulic fracture job design,which is affected by various parameters including rock strength and depth.Various methods including modelling and experimental approaches exist to quantify the breakdown pressure.There have been many strategies to reduce this pressure for efficient and economical hydraulic fracture jobs,especially when this pressure exceeds pump capacity.This study provides a detailed review of breakdown pressure in terms of fundamentals,influencing factors,and estimation approaches.In addition,different strategies are also presented to reduce the breakdown pressure along with cost analysis.Lastly,research gaps pertinent to this area are highlighted for emphasis in future research.Specifically,it has been found that high breakdown pressure is associated with challenges,but there are no comprehensive techniques and strategies to lower this pressure in formations with very high in situ stress profiles or complicated tectonic settings.Developing such methods is important to minimize operational failures,lower costs and reduce the environmental risks during reservoir exploitation.This study reviews the fundamentals,influencing factors,and estimation methods of breakdown pressure and provides a deep understanding of the strategies for its reduction.The study also presents the cost analyses,and highlights research gaps for future investigation.
基金Funding was provided by the U.S.Department of Energy,Office of Nuclear Energy,Spent Fuel and Waste Disposition,under Contract Number DE-AC02-05CH11231 with Lawrence Berkeley National Laboratory(LBNL).
文摘An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-hydromechanical(THM)coupled simulations were conducted using the TOUGH + FLAC3D simulator to predict the THM behaviors of a generic nuclear waste repository over 100,000 years following closure.The designed engineered barrier system(EBS)consists of the waste canister,backfill,and concrete liner.The objective of this study is to evaluate the long-term performance of the repository in the presence of continued hydrogen(H_(2))and heat release around the canister.The simulation results show that thermal pressurization and gas accumulation significantly raise the pore pressure within the EBS and surrounding host rock,while the peak pore pressure is not likely to exceed the lithostatic stress so that there is no risk of widespread hydro-fracturing in the host rock.However,tension failure and fracturing can occur at the tunnel scale because of internal gas buildup.Meanwhile,the generated H_(2) continuously migrates outward and tends to accumulate in the concrete liner and excavation disturbed zone surrounding the tunnel because of lower capillary pressure.Nevertheless,the fluids that may contain radionuclides will not leach into the confining units over a 100,000-year time frame.Our analysis indicates that for the assumed disposal system in Opalinus Clay,the generated heat and gas can gradually be transported through the host rock without significantly disturbing the isolation characteristics of the repository.
