The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted...The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.展开更多
Deep coal reservoirs(buried depth>2000 m)represent a significant yet underexploited resource for coalbed methane(CBM)production.In these reservoirs,CBM primarily exists in adsorbed and free phase,with the pore stru...Deep coal reservoirs(buried depth>2000 m)represent a significant yet underexploited resource for coalbed methane(CBM)production.In these reservoirs,CBM primarily exists in adsorbed and free phase,with the pore structure playing a critical role in gas storage and migration.The Jiaxian block in the northeastern Ordos Basin,has emerged as a key area for deep CBM exploration due to its promising resource potential.However,the pore structure characteristics of the No.8 coal seam in Jiaxian block and their implications for gas storage and production remain poorly understood.A comprehensive characterization of the No.8 coal seam's pore structure is conducted in the study using multiple methods including high-pressure mercury injection,N2/CO_(2)adsorption experiments,and integration of measured core gas content data and production history.The study results reveal that the pores can be mainly classified as vesicles and cellular pores,and the fractures are mainly static pressure fractures.Micropores(pore diameter<10 nm)dominate the pore system(accounting for more than 99%of the total specific surface area),providing important adsorption sites for gas storage.Although mesopores(pore diameter of 100-1000 nm)and macropores(pore diameter>1000 nm)account for a small proportion,they feature effective storage spaces and interconnectivity,resulting in a high proportion of free gas.Therefore,the reservoirs shows great development potential after stimulation(such as hydraulic fracturing).These findings emphasize the feasibility of large-scale and long-term development of CBM in the Jiaxian block in terms of reservoir space,gas content and production characteristics.This study serves to lay a scientific basis for its efficient exploitation.展开更多
The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of th...The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of the mudstone in the Shuixigou Group,especially the mudstone at the top of the Sangonghe Formation,are unclear.Taking the source rocks of the Xishanyao Formation and the Sangonghe Formation as objectives,this study conducted rock pyrolysis and gold tube simulation experiment to investigate their hydrocarbon generation characteristics and differences.Our results indicate that the source rocks of the Xishanyao Formation include mudstone,carbonaceous mudstone and coal,and the quality of the source rocks is highly heterogeneous;the source rocks of the Sangonghe Formation are mainly composed of mudstone,and it is a good gas source rock.Simulation experiments found that the activation energy required for the generation of gaseous hydrocarbons by the mudstone of the Sangonghe Formation is lower than that by the mudstone of the Xishanyao Formation.The hydrocarbon generation process can be divided into three stages for both formations,but the gas generation potential of the Xishanyao Formation mudstone is higher than that of the Sangonghe Formation mudstone.A large amount of hydrocarbon was generated by the mudstone of the Xishanyao Formation when entering late thermal evolution,of which methane is dominant,mainly from the demethylation reaction of mature kerogen.On the other hand,a large amount of hydrocarbon was generated by the mudstone of the Sangonghe Formation in the early stage of thermal evolution,of which light hydrocarbon and wet gas are dominant,mainly from the early cracking stage of kerogen.This difference may be attributed to the structure of kerogen.The mudstone of the Xishanyao Formation is conducive to the formation of highly mature dry gas reservoirs,while the mudstone of the Sangonghe Formation is conducive to the formation of low maturity condensate gas and volatile oil reservoirs.The research result provides a scientific basis for the comparison of oil and gas sources and the evaluation of oil and gas resources in the Turpan-Hami Basin.展开更多
It was previously deemed that volcanic rocks in the western Sichuan Basin were not developed,which restricted the exploration of volcanic gas reservoirs in this area.Recently,however,Sinopec's wildcat well,Well YS...It was previously deemed that volcanic rocks in the western Sichuan Basin were not developed,which restricted the exploration of volcanic gas reservoirs in this area.Recently,however,Sinopec's wildcat well,Well YS1 encounters Upper Permian volcanic rocks about 300 m thick in the western Sichuan Basin,the reservoir physical properties of which are good with strong gas shows.In order to evaluate the exploration prospect of volcanic gas reservoirs in western Sichuan Basin,we studied the Permian volcanic rocks in this area from the aspects of formation and development characteristics,reservoir characteristics,gas genesis and plays based on the new understandings on exploration wells,com-bined with the analysis on tectonic evolution and its controlling effect on volcanism.Then,the volcanic eruption mechanism,the distribution mode of volcanic edifice and the hydrocarbon accumulation pattern of volcanic gas reservoir were figured out.Finally,the exploration potential of natural gas was evaluated.The following research results were obtained:(1)the Permian volcanic rocks in western Sichuan Basin are well developed and its tectonic setting is consistent with that of Emeishan basalt,which is the product of the Emeishan mantle plume.(2)Under the control of vertical faults,a great number of volcanic edifices are developed and there are many eruption cycles.Volcanic rocks are superimposed vertically and connected laterally.(3)The volcanic rocks in western Sichuan Basin are different to some extent from those in southwestern Sichuan Basin in terms of lithology,lithofacies and reservoir characteristics.In the western Sichuan Basin,the tuff of explosive facies is dominant with some basalt of effusive facies,and the reservoir space of volcanic rocks is mainly acted by inter-breccia skeletal pores,dissolved pores and matrix micro-pores.In conclusion,multiple sets of effective source rocks are developed around the volcanic intervals in western Sichuan Basin,and together they constitute effective natural gas plays.Therefore,it has a better natural gas exploration prospect,and it is a new field worthy of attention.展开更多
Energy fluctuation of ideal Fermi gas trapped under generic power law potential U=Σ_(i=1)~d c_i|x_i/a_i|^(n_i) has been calculated in arbitrary dimensions.Energy fluctuation is scrutinized further in the degenerate l...Energy fluctuation of ideal Fermi gas trapped under generic power law potential U=Σ_(i=1)~d c_i|x_i/a_i|^(n_i) has been calculated in arbitrary dimensions.Energy fluctuation is scrutinized further in the degenerate limit μ>>K_B T with the help of Sommerfeld expansion.The dependence of energy fluctuation on dimensionality and power law potential is studied in detail.Most importantly our general result can not only exactly reproduce the recently published result regarding free and harmonically trapped ideal Fermi gas in d =3 but also can describe the outcome for any power law potential in arbitrary dimension.展开更多
Considering the discrete nonlinear Schrodinger model with dipole-dipole interactions （DDIs）, we comparatively and numerically study the effects of contact interaction, DDI and disorder on the properties of diffusion...Considering the discrete nonlinear Schrodinger model with dipole-dipole interactions （DDIs）, we comparatively and numerically study the effects of contact interaction, DDI and disorder on the properties of diffusion of dipolar condensate in one-dimensional quasi-periodic potentials. Due to the coupled effects of the contact interaction and the DDI, some new and interesting mechanisms are found： both the DDI and the contact interaction can destroy localization and lead to a subdiffusive growth of the second moment of the wave packet. However, compared with the contact interaction, the effect of DDI on the subdiffusion is stronger. Furthermore and interestingly, we find that when the contact interaction （λ1） and DDI （A2） satisfy λ1 ≥ 2λ2, the property of the subdiffusion depends only on contact interaction; when λ1 ≤ 2λ2, the property of the subdiffusion is completely determined by DDI. Remarkably, we numerically give the critical value of disorder strength v＊ for different values of contact interaction and DDI. When the disorder strength v ≥ v＊, the wave packet is localized. On the contrary, when the disorder strength v ≤ v＊, the wave packet is subdiffusive.展开更多
The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U =∑~d_（i=1）ci｜xi/ai｜~（ni） are studied carefully. Detailed calculation of Kim et al.（J. Phys...The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U =∑~d_（i=1）ci｜xi/ai｜~（ni） are studied carefully. Detailed calculation of Kim et al.（J. Phys. Condens. Matter 11（1999） 10269） yielded the hierarchy of condensation transitions with changing fractional dimensionality. In this manuscript, some theorems regarding specific heat at constant volume CV are presented. Careful examination of these theorems reveal the existence of hidden hierarchy of the condensation transition in trapped systems as well.展开更多
Previously we have determined the dilute mixture transport properties of slightly polar fluorocarbons using the inverted intermolecular potential energies(Ind. Eng. Chem. Res. 45(2006) 9211–9223). In the present pape...Previously we have determined the dilute mixture transport properties of slightly polar fluorocarbons using the inverted intermolecular potential energies(Ind. Eng. Chem. Res. 45(2006) 9211–9223). In the present paper, the corresponding states correlations for reduced viscosity collision integrals were employed to obtain effective unlike interaction potential models for dilute binary mixtures of highly polar molecule ammonia with noble gases.The inverted potentials were fitted to the Morse–Spline–van der Waals(MSV), model potential. The method of least-squares fitting was then applied to identify best consistence force parameters for each ammonia-noble gas mixture, taking advantage of experimental viscosities, diffusion coefficients and thermal conductivities.The proposed potential models were compared with those obtained from other sources, in order to assess the extent of their validity.The potentials were later employed to calculate transport properties of the studied mixtures. Then, results were compared with those reported in the literature, which led to the acceptable agreement.展开更多
A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs ...A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs in a coalbed gas field in central China to optimize wellsite locations in the studied area in combination with the dynamic data about actual production in the coalbed gas field, selects a favorable subarea for gas wells deployment. The method is established based on the basic properties of coal reservoirs, in combination with the coalbed thickness and the gas content to make an analysis of the gas storage potential of a coal reservoir, as well as resources volume and the permeability of a coal reservoir. This method can be popularized for optimization of wellsite locations in other methane gas development areas or blocks.展开更多
This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter ...This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter by determining its environmental conditions using data from geochemical analysis of core(pyrolysis)and oil(biomarkers and carbon isotopic compositions)samples.According to the geochemical parameters obtained by pyrolysis,the oil generation potential of the original rocks of most studied samples varies from poor to rich.The facies–genetic organic matter is predominantly humic and less frequently humus–sapropel,indicating organic matter accumulation in the studied samples were under moderately reducing conditions(kerogenⅢand Ⅱ types)and coastal–marine environments(kerogen typeⅠ).The carbon isotopic compositions of oils derived from the Jurassic deposits of the Aryskum Depression also indicate the sapropelic and mixed humic–sapropelic type of organic matter(kerogenⅡandⅠ).Biomarker analysis of oils indicates original organic matter formation in an anoxic environment.展开更多
The southwestern depression of the Qiongdongnan Basin(QDNB)hosts thick Cenozoic sediments and awaits major hydrocarbon discovery.Multichannel seismic(MCS)profile CFT2011 across the southwestern QDNB reveals a~60-km-wi...The southwestern depression of the Qiongdongnan Basin(QDNB)hosts thick Cenozoic sediments and awaits major hydrocarbon discovery.Multichannel seismic(MCS)profile CFT2011 across the southwestern QDNB reveals a~60-km-wide fuzzy reflection zone(FRZ)within the sediments,but its origin and distribution remain unclear.Here ocean bottom seismometer(OBS)data of Line CFT2011 are processed with focus on the velocity structures by traveltime tomography inversion and analyzed together with the coincident and adjacent MCS profiles.The OBS velocity results show that the giant FRZ features lower velocity with difference up to 1.5 km/s and smaller vertical velocity gradient than the surrounding sedimentary sequences at the same depth,likely resulting from enhanced fluid infilling.The MCS profile exhibits that the giant FRZ is about 3-9-km thick and extends from the Paleogene strata rich in organic matters upward to the lower Pleistocene sediments.Within the shallow overlying sediments,multiple bright spots with reverse polarity are imaged and their reflection amplitudes increase with offset,consistent with the features of gas-charged sediments.They are probably shallow gas reservoirs with gases sourced from the deep FRZ.Therefore,the FRZ is proposed to be a giant gas-charged zone,which probably contains lots of hydrocarbon gases migrated vertically from the deep Paleogene source rocks through the boundary faults of the depressions and the minor fractures generated under overpressure.This FRZ is also imaged on the adjacent MCS profiles MCS-L1 and MCS-L2 with the width of about 40 km and 68 km,respectively.It is roughly estimated to cover an area of~1900 km2 and host a volume of~11400 km3 assuming an average thickness of 6 km,implying huge natural gas potential in the sedimentary depression of the southwestern QDNB of the South China Sea.展开更多
The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early P...The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling-Qilian oceanic crust subduction and ocean closure, the Caledonides were formed and the foreland basin was superimposed upon. Being influenced by the Paleo-Tethyan extension, intra-continental rifting-margin basins were formed in Late Paleozoic. Following the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. The Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai-Tibet Plateau domes. Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoircap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages, and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoige and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.展开更多
Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicat...Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicated structures, features and evolution of Hefei Basin in Early Cretaceous in this study, and it was derived that that Hefei Basin was a composite basin formed during the transformation of the stress field from compressive toward tensile in Early Cretaceous. In other words, this basin was a foreland basin of gliding-thrust type, which is mainly controlled by the Dabie orogenic belt in the south side in the early to middle period of Early Cretaceous, while being a strike-slip basin of pull-apart type, which is mainly controlled by the activity of Tanlu fracture in the east side in the middle to late period of Early Cretaceous. Moreover, the potential Lower Cretaceous oil and gas system in the pull-apart basin and the vista for its prospecting were explored in this study. Tectonism of the Tanlu fracture was further discussed based on the results of characterization of the basin, and it was pointed out that this is beneficial and instructive to the oil and gas prospecting in Hefei Basin展开更多
By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarifie...By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarified.Reconstruct the current geothermal field of the sag and restore the tectonic-thermal evolution process to predict the type,scale,and distribution of resources in Baiyun Sag through thermal pressure simulation experiments and numerical simulation.The Baiyun Sag is characterized by the development of Paleogene shallow lacustrine source rocks,which are deposited in a slightly oxidizing environment.The source rocks are mainly composed of terrestrial higher plants,with algae making a certain contribution,and are oil and gas source rocks.Current geothermal field of the sag was reconstructed,in which the range of geothermal gradients is(3.5–5.2)℃/100 m,showing an overall increasing trend from northwest to southeast,with significant differences in geothermal gradients across different sub-sags.Baiyun Sag has undergone two distinct periods of extensional process,the Eocene and Miocene,since the Cenozoic era.These two periods of heating and warming events have been identified,accelerating the maturation and evolution of source rocks.The main body of ancient basal heat flow value reached its highest at 13.82 Ma.The basin modelling results show that the maturity of source rocks is significantly higher in Baiyun main sub-sag than that in other sub-sags.The Eocene Wenchang Formation is currently in the stage of high maturity to over maturity,while the Eocene Enping Formation has reached the stage of maturity to high maturity.The rock thermal simulation experiment shows that the shallow lacustrine mudstone of the Wenchang Formation has a good potential of generating gas from kerogen cracking with high gas yield and long period of gas window.Shallow lacustrine mudstone of the Enping Formation has a good ability to generate light oil,and has ability to generate kerogen cracking gas in the late stage.The gas yield of shallow lacustrine mudstone of the Enping Formation is less than that of shallow lacustrine mudstone of the Wenchang Formation and the delta coal-bearing mudstone of the Enping Formation.The numerical simulation results indicate that the source rocks of Baiyun main sub-sag generate hydrocarbons earlier and have significantly higher hydrocarbon generation intensity than other sub-sags,with an average of about 1200×10^(4)t/km^(2).Oil and gas resources were mainly distributed in Baiyun main sub-sag and the main source rocks are distributed in the 3^(rd)and 4^(th)members of Wenchang Formation.Four favorable zones are selected for the division and evaluation of migration and aggregation units:No.(1)Panyu 30 nose-shaped structural belt,No.(3)Liuhua 29 nose-shaped uplift belt and Liwan 3 nose-shaped uplift belt,No.(2)gentle slope belt of Baiyun east sag,and No.(8)Baiyun 1 low-uplift.展开更多
The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential ...The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential of high-quality shale.In this paper,the Lower Carboniferous Luzhai shale was taken as the research object in order to guide the exploration of Carboniferous shale gas in the Guizhong Depression.Based on the field outcrops,well drilling,well logging and test data of the Guizhong Depression and its surrounding areas,the shale formation was studied systematically based on the characteristics of distribution,organic geochemistry and reservoir,and the preservation conditions.Then,the development characteristics of black shale were confirmed and the distribution laws of high-quality shale were summarized.Finally,shale gas exploration was analyzed and the favorable exploration areas were defined.And the following research results were obtained.First,the Luzhai shale in the Guizhong Depression is mainly carbonaceous shale and siliceous shale of deepwater continental shelf facies.Second,the high-quality Luzhai shale is 20-60 m thick and it is characterized by high total organic carbon,good type of organic matters,moderate maturity of organic matter,high content of brittle minerals,good reservoir property and developed pores of organic matters.Third,regional caprocks and roofs&floors are well developed in the Liucheng Slope and the Yishan Sag.They are weakly deformed,suffer from less uplift and denudation,and are far away from the strong strikeeslip reverse fault,so they have good preservation conditions.Fourth,shallow wells which were drilled in the surface structures of the Guizhong Depression in the early stage present abundant gas shows,and most of them produce gas flow,which reveals a promising prospect of shale gas exploration in this area.In conclusion,the wide and gentle synclines with large burial depth in the Liucheng Slope and the Yishan Sag are the favorable areas for shale gas exploration in the Guizhong Depression.展开更多
Recently,a high-yield gas flow of 22.5×10^(4)m^(3)/d was achieved in the wildcat well Yongtan 1,deployed by PetroChina Southwest Oil and Gasfield Company,and an extrusive facies volcaniclastic gas reservoir was f...Recently,a high-yield gas flow of 22.5×10^(4)m^(3)/d was achieved in the wildcat well Yongtan 1,deployed by PetroChina Southwest Oil and Gasfield Company,and an extrusive facies volcaniclastic gas reservoir was first discovered in the Sichuan Basin,which is a major breakthrough in the exploration of volcanic rock gas reservoirs.In order to further evaluate the exploration potential in Permian volcanic rock gas reservoirs in this basin,we systematically reviewed and summarized the exploration process of volcanic rocks in this study area,as well as the characteristics of gas reservoirs of well Yongtan 1,the controlling factors and modes of hydrocarbon accumulation.The following findings were obtained.(1)Over the past five decades of gas exploration of volcanic rocks,the change of exploration thought and progress in seismic prediction contribute to a major discovery in this study area,i.e.,the well location deployment of Yongtan 1 was determined in the Jianyan area,where the volcanic anomalies of the Permian developed outbursts are well developed and the gas reservoir conditions are favorable.This also proves that another new gas exploration area in this basin was found.(2)From the data of Yongtan 1,we found high-quality volcanic porous reservoirs with a thickness of over 100 m developed in the Permian strata,the effusive volcanic rock types dominated by breccia and tuffaceous breccia,reservoir space composed of dissolution pores,interbreccia dissolution pores,and other pores,the porosity of which is 6.68%-13.22%and 10.26%on average,the permeability 0.01-4.43 mD and 2.35 mD on average.(3)This abnormally high pressure gas reservoir was buried 4500-6000 m deep underground with the middle formation pressure being 125.625 MPa and the pressure coefficient being up to 2.22.Methane content in the minor H_(2)S-bearing produced gas flow reached up to 99.03%.(4)Volcanic rocks in the Jianyang-Zhongjiang-Santai area are developed,and they are adjacent to the Cambrian high-quality source rocks in the Deyang-Anyue rifting.The early extensional deep faults play a role in connecting source and storage.There are many sets of caprocks,such as the Upper Permian Longtan Formation and Lower Triassic layered thick paste rocks,providing conditions for forming large-scale tectonic-lithologic composite trap gas reservoirs,and the favorable exploration area reaches up to 6000 km^(2).In conclusion,this major discovery not only proves that Permian volcanic rocks in the Sichuan Basin has large potential for oil and gas exploration,but reaffirms the confidence in changing our exploration thought,speeding up new exploration zones and areas,and discovering more and bigger gas fields.展开更多
Transport of gas through pipelines is the most energy-intensive production. About 80% of the energy of the whole oil and gas production is used for the gas transportation through pipelines. To that end, enhancement of...Transport of gas through pipelines is the most energy-intensive production. About 80% of the energy of the whole oil and gas production is used for the gas transportation through pipelines. To that end, enhancement of the efficiency and energy saving in the field of gas transport are solved with the aid of the basic thermodynamic relations which are mainly presented in this article.展开更多
The study on the factors influencing the biogenic gas production of low rank coal beds is of great significance to the search of the favorable biogenic gas enrichment areas of similar coal beds and the guidance of the...The study on the factors influencing the biogenic gas production of low rank coal beds is of great significance to the search of the favorable biogenic gas enrichment areas of similar coal beds and the guidance of the microbial stimulation technologies.In this paper,the lignite samples taken from the Jiergalangtu Sag in the Erlian Basin were selected to carry out the simulation experiment of biogenic coalbed methane under different temperatures,pH values,oxidation-reduction potentials(Eh)and trace element concentrations.Then,the influences on biogenic gas production were discussed and the optimal biogenic gas production condition was determined.And the following research results were obtained.First,in the simulation experiments,the biogenic gas production of coal beds increases first and then decreases with the increase of temperature,pH and trace element concentration and the decrease of Eh.Second,in the case of temperature 30-35℃,pH 7.0-7.5 and Eh 225 mV,the metabolism of methanogen is the most active and the most favorable for the generation of biogenic gas,so biogenic gas production can be promoted by adding the trace elements(Fe^(2+)and Ni^(2+))of proper concentration.It is concluded that a proper burial depth(300-600 m),a weak runoff hydrodynamic condition and an anaerobic environment constitute the favorable conditions for the generation of biogenic gas in the Jiergalangtu Sag,Erlian Basin.Moreover,the addition of appropriate trace elements can be an effective means of microbial stimulation.展开更多
基金supported by Joint Fund Project of National Natural Science Foundation(No.U22B6002)CNPC Scientific Research and Technology Development Project(No.2023ZZ14YJ02).
文摘The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.
基金funded by the National Key R&D Program of China(2024YFC2909400)the National Natural Science Foundation of China(42402180,42202195)the tackling applied science and technology projects of China National Petroleum Corporation(2023ZZ18)。
文摘Deep coal reservoirs(buried depth>2000 m)represent a significant yet underexploited resource for coalbed methane(CBM)production.In these reservoirs,CBM primarily exists in adsorbed and free phase,with the pore structure playing a critical role in gas storage and migration.The Jiaxian block in the northeastern Ordos Basin,has emerged as a key area for deep CBM exploration due to its promising resource potential.However,the pore structure characteristics of the No.8 coal seam in Jiaxian block and their implications for gas storage and production remain poorly understood.A comprehensive characterization of the No.8 coal seam's pore structure is conducted in the study using multiple methods including high-pressure mercury injection,N2/CO_(2)adsorption experiments,and integration of measured core gas content data and production history.The study results reveal that the pores can be mainly classified as vesicles and cellular pores,and the fractures are mainly static pressure fractures.Micropores(pore diameter<10 nm)dominate the pore system(accounting for more than 99%of the total specific surface area),providing important adsorption sites for gas storage.Although mesopores(pore diameter of 100-1000 nm)and macropores(pore diameter>1000 nm)account for a small proportion,they feature effective storage spaces and interconnectivity,resulting in a high proportion of free gas.Therefore,the reservoirs shows great development potential after stimulation(such as hydraulic fracturing).These findings emphasize the feasibility of large-scale and long-term development of CBM in the Jiaxian block in terms of reservoir space,gas content and production characteristics.This study serves to lay a scientific basis for its efficient exploitation.
基金supported by the China Petroleum Science and Technology Major Project(No.2023ZZ18-03).
文摘The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of the mudstone in the Shuixigou Group,especially the mudstone at the top of the Sangonghe Formation,are unclear.Taking the source rocks of the Xishanyao Formation and the Sangonghe Formation as objectives,this study conducted rock pyrolysis and gold tube simulation experiment to investigate their hydrocarbon generation characteristics and differences.Our results indicate that the source rocks of the Xishanyao Formation include mudstone,carbonaceous mudstone and coal,and the quality of the source rocks is highly heterogeneous;the source rocks of the Sangonghe Formation are mainly composed of mudstone,and it is a good gas source rock.Simulation experiments found that the activation energy required for the generation of gaseous hydrocarbons by the mudstone of the Sangonghe Formation is lower than that by the mudstone of the Xishanyao Formation.The hydrocarbon generation process can be divided into three stages for both formations,but the gas generation potential of the Xishanyao Formation mudstone is higher than that of the Sangonghe Formation mudstone.A large amount of hydrocarbon was generated by the mudstone of the Xishanyao Formation when entering late thermal evolution,of which methane is dominant,mainly from the demethylation reaction of mature kerogen.On the other hand,a large amount of hydrocarbon was generated by the mudstone of the Sangonghe Formation in the early stage of thermal evolution,of which light hydrocarbon and wet gas are dominant,mainly from the early cracking stage of kerogen.This difference may be attributed to the structure of kerogen.The mudstone of the Xishanyao Formation is conducive to the formation of highly mature dry gas reservoirs,while the mudstone of the Sangonghe Formation is conducive to the formation of low maturity condensate gas and volatile oil reservoirs.The research result provides a scientific basis for the comparison of oil and gas sources and the evaluation of oil and gas resources in the Turpan-Hami Basin.
基金Project supported by Sinopec Science and Technology Special Project“Evaluation of Hydrocarbon Formation Conditions and Targets of Permian Volcanic Rocks in Western Sichuan”(No.P18069-3)National Science and Technology Major Special Project“Evaluation and Strategic zone selection of Hydrocarbon Resources Potential of Marine Carbonate Strata”(No.2017ZX05005001-004).
文摘It was previously deemed that volcanic rocks in the western Sichuan Basin were not developed,which restricted the exploration of volcanic gas reservoirs in this area.Recently,however,Sinopec's wildcat well,Well YS1 encounters Upper Permian volcanic rocks about 300 m thick in the western Sichuan Basin,the reservoir physical properties of which are good with strong gas shows.In order to evaluate the exploration prospect of volcanic gas reservoirs in western Sichuan Basin,we studied the Permian volcanic rocks in this area from the aspects of formation and development characteristics,reservoir characteristics,gas genesis and plays based on the new understandings on exploration wells,com-bined with the analysis on tectonic evolution and its controlling effect on volcanism.Then,the volcanic eruption mechanism,the distribution mode of volcanic edifice and the hydrocarbon accumulation pattern of volcanic gas reservoir were figured out.Finally,the exploration potential of natural gas was evaluated.The following research results were obtained:(1)the Permian volcanic rocks in western Sichuan Basin are well developed and its tectonic setting is consistent with that of Emeishan basalt,which is the product of the Emeishan mantle plume.(2)Under the control of vertical faults,a great number of volcanic edifices are developed and there are many eruption cycles.Volcanic rocks are superimposed vertically and connected laterally.(3)The volcanic rocks in western Sichuan Basin are different to some extent from those in southwestern Sichuan Basin in terms of lithology,lithofacies and reservoir characteristics.In the western Sichuan Basin,the tuff of explosive facies is dominant with some basalt of effusive facies,and the reservoir space of volcanic rocks is mainly acted by inter-breccia skeletal pores,dissolved pores and matrix micro-pores.In conclusion,multiple sets of effective source rocks are developed around the volcanic intervals in western Sichuan Basin,and together they constitute effective natural gas plays.Therefore,it has a better natural gas exploration prospect,and it is a new field worthy of attention.
文摘Energy fluctuation of ideal Fermi gas trapped under generic power law potential U=Σ_(i=1)~d c_i|x_i/a_i|^(n_i) has been calculated in arbitrary dimensions.Energy fluctuation is scrutinized further in the degenerate limit μ>>K_B T with the help of Sommerfeld expansion.The dependence of energy fluctuation on dimensionality and power law potential is studied in detail.Most importantly our general result can not only exactly reproduce the recently published result regarding free and harmonically trapped ideal Fermi gas in d =3 but also can describe the outcome for any power law potential in arbitrary dimension.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274255 and 11305132the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grand No 20136203110001+1 种基金the Natural Science Foundation of Gansu Province under Grant No 2011GS04358the Creation of Science and Technology of Northwest Normal University under Grant Nos NWNU-KJCXGC-03-48 and NWNU-LKQN-12-12
文摘Considering the discrete nonlinear Schrodinger model with dipole-dipole interactions （DDIs）, we comparatively and numerically study the effects of contact interaction, DDI and disorder on the properties of diffusion of dipolar condensate in one-dimensional quasi-periodic potentials. Due to the coupled effects of the contact interaction and the DDI, some new and interesting mechanisms are found： both the DDI and the contact interaction can destroy localization and lead to a subdiffusive growth of the second moment of the wave packet. However, compared with the contact interaction, the effect of DDI on the subdiffusion is stronger. Furthermore and interestingly, we find that when the contact interaction （λ1） and DDI （A2） satisfy λ1 ≥ 2λ2, the property of the subdiffusion depends only on contact interaction; when λ1 ≤ 2λ2, the property of the subdiffusion is completely determined by DDI. Remarkably, we numerically give the critical value of disorder strength v＊ for different values of contact interaction and DDI. When the disorder strength v ≥ v＊, the wave packet is localized. On the contrary, when the disorder strength v ≤ v＊, the wave packet is subdiffusive.
文摘The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U =∑~d_（i=1）ci｜xi/ai｜~（ni） are studied carefully. Detailed calculation of Kim et al.（J. Phys. Condens. Matter 11（1999） 10269） yielded the hierarchy of condensation transitions with changing fractional dimensionality. In this manuscript, some theorems regarding specific heat at constant volume CV are presented. Careful examination of these theorems reveal the existence of hidden hierarchy of the condensation transition in trapped systems as well.
文摘Previously we have determined the dilute mixture transport properties of slightly polar fluorocarbons using the inverted intermolecular potential energies(Ind. Eng. Chem. Res. 45(2006) 9211–9223). In the present paper, the corresponding states correlations for reduced viscosity collision integrals were employed to obtain effective unlike interaction potential models for dilute binary mixtures of highly polar molecule ammonia with noble gases.The inverted potentials were fitted to the Morse–Spline–van der Waals(MSV), model potential. The method of least-squares fitting was then applied to identify best consistence force parameters for each ammonia-noble gas mixture, taking advantage of experimental viscosities, diffusion coefficients and thermal conductivities.The proposed potential models were compared with those obtained from other sources, in order to assess the extent of their validity.The potentials were later employed to calculate transport properties of the studied mixtures. Then, results were compared with those reported in the literature, which led to the acceptable agreement.
文摘A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs in a coalbed gas field in central China to optimize wellsite locations in the studied area in combination with the dynamic data about actual production in the coalbed gas field, selects a favorable subarea for gas wells deployment. The method is established based on the basic properties of coal reservoirs, in combination with the coalbed thickness and the gas content to make an analysis of the gas storage potential of a coal reservoir, as well as resources volume and the permeability of a coal reservoir. This method can be popularized for optimization of wellsite locations in other methane gas development areas or blocks.
基金Funding from the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan under Grant Agreement No.AP13268843.
文摘This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter by determining its environmental conditions using data from geochemical analysis of core(pyrolysis)and oil(biomarkers and carbon isotopic compositions)samples.According to the geochemical parameters obtained by pyrolysis,the oil generation potential of the original rocks of most studied samples varies from poor to rich.The facies–genetic organic matter is predominantly humic and less frequently humus–sapropel,indicating organic matter accumulation in the studied samples were under moderately reducing conditions(kerogenⅢand Ⅱ types)and coastal–marine environments(kerogen typeⅠ).The carbon isotopic compositions of oils derived from the Jurassic deposits of the Aryskum Depression also indicate the sapropelic and mixed humic–sapropelic type of organic matter(kerogenⅡandⅠ).Biomarker analysis of oils indicates original organic matter formation in an anoxic environment.
基金Supported by the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515011836,2021A1515110851)the Science and Technology Planning Project of Guangzhou(No.202201010230)+5 种基金the Special Support Program for Cultivating High-Level Talents in Guangdong Province(No.2019BT02H594)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0104)the Open Fund of Key Laboratory of Marine Geology and EnvironmentChinese Academy of Sciences(CAS)(No.MGE2020KG01)the National Natural Science Foundation of China(Nos.U1901217,91855101,41876052,42076218)Dr.Junhui YU is funded by the Special Research Assistant Funding Program of CAS。
文摘The southwestern depression of the Qiongdongnan Basin(QDNB)hosts thick Cenozoic sediments and awaits major hydrocarbon discovery.Multichannel seismic(MCS)profile CFT2011 across the southwestern QDNB reveals a~60-km-wide fuzzy reflection zone(FRZ)within the sediments,but its origin and distribution remain unclear.Here ocean bottom seismometer(OBS)data of Line CFT2011 are processed with focus on the velocity structures by traveltime tomography inversion and analyzed together with the coincident and adjacent MCS profiles.The OBS velocity results show that the giant FRZ features lower velocity with difference up to 1.5 km/s and smaller vertical velocity gradient than the surrounding sedimentary sequences at the same depth,likely resulting from enhanced fluid infilling.The MCS profile exhibits that the giant FRZ is about 3-9-km thick and extends from the Paleogene strata rich in organic matters upward to the lower Pleistocene sediments.Within the shallow overlying sediments,multiple bright spots with reverse polarity are imaged and their reflection amplitudes increase with offset,consistent with the features of gas-charged sediments.They are probably shallow gas reservoirs with gases sourced from the deep FRZ.Therefore,the FRZ is proposed to be a giant gas-charged zone,which probably contains lots of hydrocarbon gases migrated vertically from the deep Paleogene source rocks through the boundary faults of the depressions and the minor fractures generated under overpressure.This FRZ is also imaged on the adjacent MCS profiles MCS-L1 and MCS-L2 with the width of about 40 km and 68 km,respectively.It is roughly estimated to cover an area of~1900 km2 and host a volume of~11400 km3 assuming an average thickness of 6 km,implying huge natural gas potential in the sedimentary depression of the southwestern QDNB of the South China Sea.
文摘The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling-Qilian oceanic crust subduction and ocean closure, the Caledonides were formed and the foreland basin was superimposed upon. Being influenced by the Paleo-Tethyan extension, intra-continental rifting-margin basins were formed in Late Paleozoic. Following the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. The Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai-Tibet Plateau domes. Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoircap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages, and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoige and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.
文摘Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicated structures, features and evolution of Hefei Basin in Early Cretaceous in this study, and it was derived that that Hefei Basin was a composite basin formed during the transformation of the stress field from compressive toward tensile in Early Cretaceous. In other words, this basin was a foreland basin of gliding-thrust type, which is mainly controlled by the Dabie orogenic belt in the south side in the early to middle period of Early Cretaceous, while being a strike-slip basin of pull-apart type, which is mainly controlled by the activity of Tanlu fracture in the east side in the middle to late period of Early Cretaceous. Moreover, the potential Lower Cretaceous oil and gas system in the pull-apart basin and the vista for its prospecting were explored in this study. Tectonism of the Tanlu fracture was further discussed based on the results of characterization of the basin, and it was pointed out that this is beneficial and instructive to the oil and gas prospecting in Hefei Basin
基金Supported by the National Oil and Gas Resource Evaluation Project for the 14th Five Year Plan of the Ministry of Natural Resources(QGYQZYPJ2022-3)China National Offshore Oil Corporation"14th Five Year Plan"Major Science and Technology Project(KJGG2022-0103-03)。
文摘By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarified.Reconstruct the current geothermal field of the sag and restore the tectonic-thermal evolution process to predict the type,scale,and distribution of resources in Baiyun Sag through thermal pressure simulation experiments and numerical simulation.The Baiyun Sag is characterized by the development of Paleogene shallow lacustrine source rocks,which are deposited in a slightly oxidizing environment.The source rocks are mainly composed of terrestrial higher plants,with algae making a certain contribution,and are oil and gas source rocks.Current geothermal field of the sag was reconstructed,in which the range of geothermal gradients is(3.5–5.2)℃/100 m,showing an overall increasing trend from northwest to southeast,with significant differences in geothermal gradients across different sub-sags.Baiyun Sag has undergone two distinct periods of extensional process,the Eocene and Miocene,since the Cenozoic era.These two periods of heating and warming events have been identified,accelerating the maturation and evolution of source rocks.The main body of ancient basal heat flow value reached its highest at 13.82 Ma.The basin modelling results show that the maturity of source rocks is significantly higher in Baiyun main sub-sag than that in other sub-sags.The Eocene Wenchang Formation is currently in the stage of high maturity to over maturity,while the Eocene Enping Formation has reached the stage of maturity to high maturity.The rock thermal simulation experiment shows that the shallow lacustrine mudstone of the Wenchang Formation has a good potential of generating gas from kerogen cracking with high gas yield and long period of gas window.Shallow lacustrine mudstone of the Enping Formation has a good ability to generate light oil,and has ability to generate kerogen cracking gas in the late stage.The gas yield of shallow lacustrine mudstone of the Enping Formation is less than that of shallow lacustrine mudstone of the Wenchang Formation and the delta coal-bearing mudstone of the Enping Formation.The numerical simulation results indicate that the source rocks of Baiyun main sub-sag generate hydrocarbons earlier and have significantly higher hydrocarbon generation intensity than other sub-sags,with an average of about 1200×10^(4)t/km^(2).Oil and gas resources were mainly distributed in Baiyun main sub-sag and the main source rocks are distributed in the 3^(rd)and 4^(th)members of Wenchang Formation.Four favorable zones are selected for the division and evaluation of migration and aggregation units:No.(1)Panyu 30 nose-shaped structural belt,No.(3)Liuhua 29 nose-shaped uplift belt and Liwan 3 nose-shaped uplift belt,No.(2)gentle slope belt of Baiyun east sag,and No.(8)Baiyun 1 low-uplift.
基金Project supported by the National Major Science and Technology Project“Shale Gas Play Evaluation and Exploration Technologies”(No.:2017ZX05036).
文摘The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential of high-quality shale.In this paper,the Lower Carboniferous Luzhai shale was taken as the research object in order to guide the exploration of Carboniferous shale gas in the Guizhong Depression.Based on the field outcrops,well drilling,well logging and test data of the Guizhong Depression and its surrounding areas,the shale formation was studied systematically based on the characteristics of distribution,organic geochemistry and reservoir,and the preservation conditions.Then,the development characteristics of black shale were confirmed and the distribution laws of high-quality shale were summarized.Finally,shale gas exploration was analyzed and the favorable exploration areas were defined.And the following research results were obtained.First,the Luzhai shale in the Guizhong Depression is mainly carbonaceous shale and siliceous shale of deepwater continental shelf facies.Second,the high-quality Luzhai shale is 20-60 m thick and it is characterized by high total organic carbon,good type of organic matters,moderate maturity of organic matter,high content of brittle minerals,good reservoir property and developed pores of organic matters.Third,regional caprocks and roofs&floors are well developed in the Liucheng Slope and the Yishan Sag.They are weakly deformed,suffer from less uplift and denudation,and are far away from the strong strikeeslip reverse fault,so they have good preservation conditions.Fourth,shallow wells which were drilled in the surface structures of the Guizhong Depression in the early stage present abundant gas shows,and most of them produce gas flow,which reveals a promising prospect of shale gas exploration in this area.In conclusion,the wide and gentle synclines with large burial depth in the Liucheng Slope and the Yishan Sag are the favorable areas for shale gas exploration in the Guizhong Depression.
基金supported by the Major Science&Technology Special Project of PetroChina Company Limited“Research and Application of Key Technologies for 300×10^(8) m^(3) Gas Productivity in Southwest Oil&Gasfield”(No.:2016E-0604).
文摘Recently,a high-yield gas flow of 22.5×10^(4)m^(3)/d was achieved in the wildcat well Yongtan 1,deployed by PetroChina Southwest Oil and Gasfield Company,and an extrusive facies volcaniclastic gas reservoir was first discovered in the Sichuan Basin,which is a major breakthrough in the exploration of volcanic rock gas reservoirs.In order to further evaluate the exploration potential in Permian volcanic rock gas reservoirs in this basin,we systematically reviewed and summarized the exploration process of volcanic rocks in this study area,as well as the characteristics of gas reservoirs of well Yongtan 1,the controlling factors and modes of hydrocarbon accumulation.The following findings were obtained.(1)Over the past five decades of gas exploration of volcanic rocks,the change of exploration thought and progress in seismic prediction contribute to a major discovery in this study area,i.e.,the well location deployment of Yongtan 1 was determined in the Jianyan area,where the volcanic anomalies of the Permian developed outbursts are well developed and the gas reservoir conditions are favorable.This also proves that another new gas exploration area in this basin was found.(2)From the data of Yongtan 1,we found high-quality volcanic porous reservoirs with a thickness of over 100 m developed in the Permian strata,the effusive volcanic rock types dominated by breccia and tuffaceous breccia,reservoir space composed of dissolution pores,interbreccia dissolution pores,and other pores,the porosity of which is 6.68%-13.22%and 10.26%on average,the permeability 0.01-4.43 mD and 2.35 mD on average.(3)This abnormally high pressure gas reservoir was buried 4500-6000 m deep underground with the middle formation pressure being 125.625 MPa and the pressure coefficient being up to 2.22.Methane content in the minor H_(2)S-bearing produced gas flow reached up to 99.03%.(4)Volcanic rocks in the Jianyang-Zhongjiang-Santai area are developed,and they are adjacent to the Cambrian high-quality source rocks in the Deyang-Anyue rifting.The early extensional deep faults play a role in connecting source and storage.There are many sets of caprocks,such as the Upper Permian Longtan Formation and Lower Triassic layered thick paste rocks,providing conditions for forming large-scale tectonic-lithologic composite trap gas reservoirs,and the favorable exploration area reaches up to 6000 km^(2).In conclusion,this major discovery not only proves that Permian volcanic rocks in the Sichuan Basin has large potential for oil and gas exploration,but reaffirms the confidence in changing our exploration thought,speeding up new exploration zones and areas,and discovering more and bigger gas fields.
文摘Transport of gas through pipelines is the most energy-intensive production. About 80% of the energy of the whole oil and gas production is used for the gas transportation through pipelines. To that end, enhancement of the efficiency and energy saving in the field of gas transport are solved with the aid of the basic thermodynamic relations which are mainly presented in this article.
基金supported by the National Science and Technology Major Project“Optimization and Evaluation of Blocks for Large-scale Development of Medium-and Low-rank Coalbed Methane(CBM)”(No.:2016ZX05041)PetroChina Major Science and Technology Project“Study and Application of Key Technologies for Exploration and Development of Coalbed Methane”(No.:2017E14).
文摘The study on the factors influencing the biogenic gas production of low rank coal beds is of great significance to the search of the favorable biogenic gas enrichment areas of similar coal beds and the guidance of the microbial stimulation technologies.In this paper,the lignite samples taken from the Jiergalangtu Sag in the Erlian Basin were selected to carry out the simulation experiment of biogenic coalbed methane under different temperatures,pH values,oxidation-reduction potentials(Eh)and trace element concentrations.Then,the influences on biogenic gas production were discussed and the optimal biogenic gas production condition was determined.And the following research results were obtained.First,in the simulation experiments,the biogenic gas production of coal beds increases first and then decreases with the increase of temperature,pH and trace element concentration and the decrease of Eh.Second,in the case of temperature 30-35℃,pH 7.0-7.5 and Eh 225 mV,the metabolism of methanogen is the most active and the most favorable for the generation of biogenic gas,so biogenic gas production can be promoted by adding the trace elements(Fe^(2+)and Ni^(2+))of proper concentration.It is concluded that a proper burial depth(300-600 m),a weak runoff hydrodynamic condition and an anaerobic environment constitute the favorable conditions for the generation of biogenic gas in the Jiergalangtu Sag,Erlian Basin.Moreover,the addition of appropriate trace elements can be an effective means of microbial stimulation.
