A new pore type,nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstru...A new pore type,nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC,R_(o)values,X-ray diffraction etc.in the Cretaceous Qingshankou Formation shale in the Songliao Basin,NE China.Such pore characteristics and evolution study show that:(1)Organo-clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates.Different from circular or oval organic pores discovered in other shales,a single organo-clay complex pore is square,rectangular,rhombic or slaty,with the pore diameter generally less than 200 nm.(2)With thermal maturity increasing,the elements(C,Si,Al,O,Mg,Fe,etc.)in organo-clay complex change accordingly,showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fracture formation.(3)At high thermal maturity,the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70%of total pore space.The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores.It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil.The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significance for the study of shale oil formation and accumulation laws.展开更多
A noise-reduction method with sliding called the local f-x Cadzow noise-reduction method, windows in the frequency-space （f-x） domain, is presented in this paper. This method is based on the assumption that the sign...A noise-reduction method with sliding called the local f-x Cadzow noise-reduction method, windows in the frequency-space （f-x） domain, is presented in this paper. This method is based on the assumption that the signal in each window is linearly predictable in the spatial direction while the random noise is not. For each Toeplitz matrix constructed by constant frequency slice, a singular value decomposition （SVD） is applied to separate signal from noise. To avoid edge artifacts caused by zero percent overlap between windows and to remove more noise, an appropriate overlap is adopted. Besides flat and dipping events, this method can enhance curved and conflicting events. However, it is not suitable for seismic data that contains big spikes or null traces. It is also compared with the SVD, f-x deconvolution, and Cadzow method without windows. The comparison results show that the local Cadzow method performs well in removing random noise and preserving signal. In addition, a real data example proves that it is a potential noise-reduction technique for seismic data obtained in areas of complex formations.展开更多
To reveal the development characteristics and distribution of gravity flow sedimentary system under micro-paleogeomorphologic units of the Chang 7 Member of Triassic Yanchang Formation in the southwestern Ordos Basin,...To reveal the development characteristics and distribution of gravity flow sedimentary system under micro-paleogeomorphologic units of the Chang 7 Member of Triassic Yanchang Formation in the southwestern Ordos Basin,on the basis of the restoration of the paleogeomorphological form of the Chang 7 depositional period by the impression method,each micro-paleogeomorphologic unit was depicted in-depth,and the characteristics and development models of gravity flow deposits in the study area were studied in combination with outcrop,core,mud logging and log data.The results show that:(1)The paleogeomorphology in the Chang 7 depositional period was an asymmetrical depression,wide and gentle in the northeast and steep and narrow in the southwest.Three sub-paleogeomorphologic units were developed in the basin,including gentle paleo-slope,paleo-slope and paleo-depression,and they can be further subdivided into eight micro-paleogeomorphologic units:bulge,groove,slope break belt,plain of lake bottom,deep depression of lake bottom,paleo-channel,paleo-ridge of lake bottom,and paleo-uplift of lake bottom.(2)There are 9 types of lithofacies and 4 types of lithofacies assemblages of Chang 7 Member.According to lithofacies composition and lithofacies vertical combination,the gravity flow deposit is further divided into 5 types of microfacies:restricted channel,unrestricted channel,natural levee,inter-channel,lobe.(3)Paleogeomorphology plays an important role in controlling sediment source direction,type and spatial distribution of sedimentary microfacies,genetic types and distribution of sand bodies in Chang 7 Member.展开更多
Drilling,seismic and logging data were used to evaluate the hydrocarbon accumulation conditions of the mound-shoal complexes in the platform margin of the fourth member of Sinian Dengying Formation in the east side of...Drilling,seismic and logging data were used to evaluate the hydrocarbon accumulation conditions of the mound-shoal complexes in the platform margin of the fourth member of Sinian Dengying Formation in the east side of the Mianzhu-Changning intracratonic rift in the Sichuan Basin.The four understandings are:(1)The platform margin belt of the Deng 4 Member can be divided into three sections,northern,middle and southern;the middle section is at the core of the Gaoshiti-Moxi paleouplift and the structural high now,while the southern and northern sections are at the slope of the paleouplift and the structural lows now;the three sections have similar development characteristics and reservoir features of platform margin mound-shoal complex.(2)In the margin of the east side of the rift,there are several faults nearly perpendicular to the platform margin belt,the faults divide the platform margin belt into rugged paleo-landform,and the high part developed platform margin mound-shoal complexes and the reservoirs are good in physical properties,while the low part developed inter-beach depression and no mound-shoal complexes,where the reservoirs are poor in physical properties.(3)The six groups of faults nearly perpendicular to the platform margin belt divide the platform margin belt into seven large mound-shoal complexes which have similar hydrocarbon accumulation conditions and accumulation evolution process and are rich in petroleum.(4)The inter shoal depressions between the mound-shoal complexes are characterized by tighter lithology,which can block the updip direction of the mounds and shoals at the lower part of the slope of the paleouplift and are favorable for the later preservation of mound-shoal gas reservoirs.This has been proved by Well Jiaotan 1 and Heshen 2 drilled successfully.The mound-shoal complexes on the platform margin of the structural slope area have a good exploration prospect.展开更多
This study investigated the characteristics and genesis of reservoirs in the 2^(nd) and 4^(th) members of Sinian Dengying Formation in northern Sichuan and its surrounding areas, on the basis of outcrop, drilling core...This study investigated the characteristics and genesis of reservoirs in the 2^(nd) and 4^(th) members of Sinian Dengying Formation in northern Sichuan and its surrounding areas, on the basis of outcrop, drilling cores and thin section observation and geochemical analysis. The reservoirs of 2^(nd) member are distributed in the middle part of the stratum. The reservoir quality is controlled by supergene karst and the distribution of mound-shoal complex. The bedded elongated isolated algal framework solution-cave and the residual "grape-lace" cave, which are partially filled with multi-stage dolosparite, constituted the main reservoir space of the 2^(nd) member. There is no asphalt distribution in the pores. The pore connectivity is poor, and the porosity and permeability of the reservoir is relatively low. The reservoirs of 4^(th) member were distributed in the upper and top part of the stratum. The reservoir quality is controlled by burial dissolution and the distribution of mound-shoal complex. The bedded algal framework solution-pores or caves, intercrystalline pores and intercrystalline dissolved pores constituted the main reservoir space of the 4^(th) member. It's partially filled with asphalt and quartz, without any dolosparite fillings in the pores and caves. The pore connectivity is good. Most of the 4^(th) member reservoirs had medium-low porosity and low permeability, and, locally, medium-high porosity and medium permeability. Affected by the development of mound-shoal complex and heterogeneous dissolution, the platform margin along Ningqiang, Guangyuan, Jiange and Langzhong is the most favorable region for reservoir development. Deep buried Dengying Formation in the guangyuan and langzhong areas should be the most important hydrocarbon target for the future exploration.展开更多
By conducting experimental analyses, including thermal pyrolysis, micro-/nano-CT, argon-ion polishing field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and two-dimensiona...By conducting experimental analyses, including thermal pyrolysis, micro-/nano-CT, argon-ion polishing field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and two-dimensional nuclear magnetic resonance (2D NMR), the Gulong shale oil in the Songliao Basin was investigated with respect to formation model, pore structure and accumulation mechanism. First, in the Gulong shale, there are a large number of pico-algae, nano-algae and dinoflagellates, which were formed in brackish water environment and constituted the hydrogen-rich oil source materials of shale. Second, most of the oil-generating materials of the Qingshankou Formation shale exist in the form of organo-clay complex. During organic matter thermal evolution, clay minerals had double effects of suppression and catalytic hydrogenation, which expanded shale oil window and increased light hydrocarbon yield. Third, the formation of storage space in the Gulong Shale was related to dissolution and hydrocarbon generation. With the diagenesis, micro-/nano-pores increased, pore diameter decreased and more bedding fractures appeared, which jointly gave rise to the unique reservoir with dual media (i.e. nano-scale pores and micro-scale bedding fractures) in the Gulong shale. Fourth, the micro-/nano-scale oil storage unit in the Gulong shale exhibits independent oil/gas occurrence phase, and shows that all-size pores contain oils, which occur in condensate state in micropores or in oil-gas two phase (or liquid) state in macropores/mesopores. The understanding about Gulong shale oil formation and accumulation mechanism has theoretical and practical significance for advancing continental shale oil exploration in China.展开更多
The water adsorption by shale significantly affects shale gas content and its seepage capacity.However,the mechanism of water adsorption by shale is still unclear due to its strong heterogeneity and complicated pore s...The water adsorption by shale significantly affects shale gas content and its seepage capacity.However,the mechanism of water adsorption by shale is still unclear due to its strong heterogeneity and complicated pore structure.The relationship between the adsorbed water content at different relative humidities(RHs)and shale compositions,as well as shale pore structure and the spatial configuration relationship between organic matter(OM)and clay minerals,was investigated to clarify the controlling factors and mechanisms of water adsorption by Longmaxi Formation shale from the Southern Sichuan Basin in China.Consequently,the water adsorption process could be generally divided into three different stages from 0%RH to 99%RH.Furthermore,the Johnston’s clay mine ral interlayer pore structure model(JCM),the Freundlich model(FM)and the Dubinin-Astakhov model(DAM)were tested to fit the three water adsorption stages from low RH to high RH,respectively.The fitting results of the JCM and FM at lower RHs were far from good,while the fitting results of DAM at higher RHs were acceptable.Accordingly,two revised models(LRHM and MRHM)considering the spatial configuration relationship between OM and clay minerals were proposed for the two stages with lower RHs,and performed better fitting results indicating the pronounced effect of the spatial configuration relationship between OM and clay minerals on the water adsorption process of Longmaxi Formation shale.The outcomes of this study will contribute to clarifying the water distribution characteristics in the pore network of shale samples with variable water contents.展开更多
Based on the seismic, logging, drilling and other data, the distribution, structural types and mound-shoal hydrocarbon accumulation characteristics of platform margins of the Sinian Dengying Formation in the Deyang-An...Based on the seismic, logging, drilling and other data, the distribution, structural types and mound-shoal hydrocarbon accumulation characteristics of platform margins of the Sinian Dengying Formation in the Deyang-Anyue Rift and its periphery were analyzed. Four types of platform margins are developed in the Dengying Formation, i.e., single-stage fault-controlled platform margin, multi-stage fault-controlled platform margin, gentle slope platform margin, and overlapping platform margin. In the Gaoshiti West-Weiyuan East area, single-stage fault controlled platform margins are developed in the Deng 2 Member, which trend in nearly NEE direction and are shielded by faults and mudstones, forming fault-controlled–lithologic traps. In the Lezhi-Penglai area, independent and multi-stage fault controlled platform margins are developed in the Deng 2 Member, which trend in NE direction and are controlled by synsedimentary faults;the mound-shoal complexes are aggraded and built on the hanging walls of the faults, and they are shielded by tight intertidal belts and the Lower Cambrian source rocks in multiple directions, forming fault-controlled–lithologic and other composite traps. In the Weiyuan-Ziyang area, gentle slope platform margins are developed in the Deng 2 Member, which trend in NW direction;the mound-shoal complexes are mostly thin interbeds as continuous bands and shielded by tight intertidal belts in the updip direction, forming lithologic traps. In the Gaoshiti-Moxi-Yanting area, overlapping platform margins are developed in the Deng 2 and Deng 4 members;the mound-shoal complexes are aggraded and overlaid to create platform margin buildup with a huge thickness and sealed by tight intertidal belts and the Lower Cambrian mudstones in the updip direction, forming large-scale lithologic traps on the north slope of the Central Sichuan Paleouplift. To summarize, the mound-shoal complexes on the platform margins in the Dengying Formation in the Penglai-Zhongjiang area, Moxi North-Yanting area and Weiyuan-Ziyang area are large in scale, with estimated resources of 1.58×1012 m3, and they will be the key targets for the future exploration of the Dengying Formation in the Sichuan Basin.展开更多
Numerous aspects of the water oxidation mechanism in photosystemⅡhave not been fully elucidated,especially the O-O bond formation pathway.However,a body of experimental evidences have identified the O5 and W2 ligands...Numerous aspects of the water oxidation mechanism in photosystemⅡhave not been fully elucidated,especially the O-O bond formation pathway.However,a body of experimental evidences have identified the O5 and W2 ligands of the oxygen-evolving complex as the highly probable substrate candidates.In this work,we studied O-O bond formation between O5 and W2 based on the native Mn4 Ca cluster by density functional calculations.Structural rearrangements before the formation of the S_(4) state were found as a prerequisite for O-O bond formation between O5 and W2,regardless if the suggested pathways involving the typical Mnl(Ⅳ)-O·species or the recently proposed Mn4(Ⅶ)(O)2 species.Possible alternatives for the S2→S_(3) and S_(3)→S_(4) transitions accounting for such required rearrangements are discussed.These findings reflect that the structural flexibility of the Mn4 Ca cluster is essential to allow structural rearrangements during the catalytic cycle.展开更多
Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/ele...Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/electric fields in 2D formations efficiently by the 2.5D finite diff erence method.Particularly,by leveraging the field’s rapid attenuation in spectral domain,we propose truncated Gauss–Hermite quadrature,which is several tens of times faster than traditional inverse fast Fourier transform.By applying the algorithm to the LWD modeling under complex formations,e.g.,folds,fault and sandstone pinch-outs,we analyze the feasibility of the dimension reduction from 2D to 1D.For the formations with smooth lateral changes,like folds,the simplified 1D model’s results agree well with the true responses,which indicate that the 1D simplification with sliding window is feasible.However,for the formation structures with drastic rock properties changes and sharp boundaries,for instance,faults and sandstone pinch-outs,the simplified 1D model will lead to large errors and,therefore,2.5D algorithms should be applied to ensure the accuracy.展开更多
In order to obtain effective parameters for complex sand reservoirs,a log evaluation method for relevant reservoir parameters is established based on an analysis in the gas-bearing sandstone with high porosity and low...In order to obtain effective parameters for complex sand reservoirs,a log evaluation method for relevant reservoir parameters is established based on an analysis in the gas-bearing sandstone with high porosity and low permeability,low porosity and permeability and on various characteristics of log responses to reservoir lithologies and physical properties in the Neopleozoic sand reservoir of the Ordos basin.This log evaluation method covers the Cook method that is used to evaluate the porosity and oiliness in high porosity and low permeability reservoirs and another method in which the mineral content,derived from geochemical logs,is used to identify formation lithologies.Some areas have high calcium and low silt content,not uniformly distributed,the results of which show up in the complex formation lithologies and conventional log responses with great deviation.The reliability of the method is verified by comparison with conventional log data and core analyses.The calculation results coincide with the core analytical data and gas tests,which indicate that this log evaluation method is available,provides novel ideas for study of similar complex reservoir lithologies and has some reference value.展开更多
Phosvitin(PV)was treated with high-temperature,mild pressure(HTMP),and enzyme combination,and then phosvitin phosphopeptides-calcium(PPP-Ca)complexes were prepared.The low-calcium specific pathogen free-Kunming(SPF-KM...Phosvitin(PV)was treated with high-temperature,mild pressure(HTMP),and enzyme combination,and then phosvitin phosphopeptides-calcium(PPP-Ca)complexes were prepared.The low-calcium specific pathogen free-Kunming(SPF-KM)mice were used to determine the effect of PPP-Ca complexes on intestinal calcium absorption and their utilization for bone formation.The serum calcium content was the highest with the HTMP-Enz-PPP-Ca treatment(2.19 mmol/L),and it significantly down-regulated the abnormal elevation of serum alkaline phosphatase(AKP)caused by calcium deficiency.The low-calcium control group had the lowest calcium deposited to the femur(80.41 mg/g)and the lowest femur bone mineral density(BMD)(0.17 g/cm^(3)),while HTMP-Enz-PPP-Ca significantly improved bone calcium content(94.33 mg/g)and BMD(0.29 g/cm^(3)).The micro-computed tomography(MCT)images showed that the femur with the normal control,PV-Ca,and HTMP-Enz-PPP-Ca treatments had a more compact,complete,and thicker trabecular network than the low-calcium and CaCl_(2)treatments.These results indicated that the organic calcium(HTMP-Enz-PPP-Ca)promoted calcium absorption and bone deposition,and the effect of HTMP-Enz-PPP-Ca was better than the inorganic CaCl_(2).展开更多
基金Supported by Central Government Guided Local Science and Technology Innovation Fund Program(ZY20B13)。
文摘A new pore type,nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC,R_(o)values,X-ray diffraction etc.in the Cretaceous Qingshankou Formation shale in the Songliao Basin,NE China.Such pore characteristics and evolution study show that:(1)Organo-clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates.Different from circular or oval organic pores discovered in other shales,a single organo-clay complex pore is square,rectangular,rhombic or slaty,with the pore diameter generally less than 200 nm.(2)With thermal maturity increasing,the elements(C,Si,Al,O,Mg,Fe,etc.)in organo-clay complex change accordingly,showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fracture formation.(3)At high thermal maturity,the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70%of total pore space.The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores.It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil.The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significance for the study of shale oil formation and accumulation laws.
基金support from the National Key Basic Research Development Program(Grant No.2007CB209600)National Major Science and Technology Program(Grant No.2008ZX05010-002)
文摘A noise-reduction method with sliding called the local f-x Cadzow noise-reduction method, windows in the frequency-space （f-x） domain, is presented in this paper. This method is based on the assumption that the signal in each window is linearly predictable in the spatial direction while the random noise is not. For each Toeplitz matrix constructed by constant frequency slice, a singular value decomposition （SVD） is applied to separate signal from noise. To avoid edge artifacts caused by zero percent overlap between windows and to remove more noise, an appropriate overlap is adopted. Besides flat and dipping events, this method can enhance curved and conflicting events. However, it is not suitable for seismic data that contains big spikes or null traces. It is also compared with the SVD, f-x deconvolution, and Cadzow method without windows. The comparison results show that the local Cadzow method performs well in removing random noise and preserving signal. In addition, a real data example proves that it is a potential noise-reduction technique for seismic data obtained in areas of complex formations.
基金Supported by the National Natural Science Foundation of China(42102170)National Key Basic Research and Development Program(973 Program),China(2014CB239003).
文摘To reveal the development characteristics and distribution of gravity flow sedimentary system under micro-paleogeomorphologic units of the Chang 7 Member of Triassic Yanchang Formation in the southwestern Ordos Basin,on the basis of the restoration of the paleogeomorphological form of the Chang 7 depositional period by the impression method,each micro-paleogeomorphologic unit was depicted in-depth,and the characteristics and development models of gravity flow deposits in the study area were studied in combination with outcrop,core,mud logging and log data.The results show that:(1)The paleogeomorphology in the Chang 7 depositional period was an asymmetrical depression,wide and gentle in the northeast and steep and narrow in the southwest.Three sub-paleogeomorphologic units were developed in the basin,including gentle paleo-slope,paleo-slope and paleo-depression,and they can be further subdivided into eight micro-paleogeomorphologic units:bulge,groove,slope break belt,plain of lake bottom,deep depression of lake bottom,paleo-channel,paleo-ridge of lake bottom,and paleo-uplift of lake bottom.(2)There are 9 types of lithofacies and 4 types of lithofacies assemblages of Chang 7 Member.According to lithofacies composition and lithofacies vertical combination,the gravity flow deposit is further divided into 5 types of microfacies:restricted channel,unrestricted channel,natural levee,inter-channel,lobe.(3)Paleogeomorphology plays an important role in controlling sediment source direction,type and spatial distribution of sedimentary microfacies,genetic types and distribution of sand bodies in Chang 7 Member.
基金Supported by the China National Science and Technology Major Project(2016ZX05007-002)
文摘Drilling,seismic and logging data were used to evaluate the hydrocarbon accumulation conditions of the mound-shoal complexes in the platform margin of the fourth member of Sinian Dengying Formation in the east side of the Mianzhu-Changning intracratonic rift in the Sichuan Basin.The four understandings are:(1)The platform margin belt of the Deng 4 Member can be divided into three sections,northern,middle and southern;the middle section is at the core of the Gaoshiti-Moxi paleouplift and the structural high now,while the southern and northern sections are at the slope of the paleouplift and the structural lows now;the three sections have similar development characteristics and reservoir features of platform margin mound-shoal complex.(2)In the margin of the east side of the rift,there are several faults nearly perpendicular to the platform margin belt,the faults divide the platform margin belt into rugged paleo-landform,and the high part developed platform margin mound-shoal complexes and the reservoirs are good in physical properties,while the low part developed inter-beach depression and no mound-shoal complexes,where the reservoirs are poor in physical properties.(3)The six groups of faults nearly perpendicular to the platform margin belt divide the platform margin belt into seven large mound-shoal complexes which have similar hydrocarbon accumulation conditions and accumulation evolution process and are rich in petroleum.(4)The inter shoal depressions between the mound-shoal complexes are characterized by tighter lithology,which can block the updip direction of the mounds and shoals at the lower part of the slope of the paleouplift and are favorable for the later preservation of mound-shoal gas reservoirs.This has been proved by Well Jiaotan 1 and Heshen 2 drilled successfully.The mound-shoal complexes on the platform margin of the structural slope area have a good exploration prospect.
基金Supported by the China National Science and Technology Major Project(2017ZX05001001-002)
文摘This study investigated the characteristics and genesis of reservoirs in the 2^(nd) and 4^(th) members of Sinian Dengying Formation in northern Sichuan and its surrounding areas, on the basis of outcrop, drilling cores and thin section observation and geochemical analysis. The reservoirs of 2^(nd) member are distributed in the middle part of the stratum. The reservoir quality is controlled by supergene karst and the distribution of mound-shoal complex. The bedded elongated isolated algal framework solution-cave and the residual "grape-lace" cave, which are partially filled with multi-stage dolosparite, constituted the main reservoir space of the 2^(nd) member. There is no asphalt distribution in the pores. The pore connectivity is poor, and the porosity and permeability of the reservoir is relatively low. The reservoirs of 4^(th) member were distributed in the upper and top part of the stratum. The reservoir quality is controlled by burial dissolution and the distribution of mound-shoal complex. The bedded algal framework solution-pores or caves, intercrystalline pores and intercrystalline dissolved pores constituted the main reservoir space of the 4^(th) member. It's partially filled with asphalt and quartz, without any dolosparite fillings in the pores and caves. The pore connectivity is good. Most of the 4^(th) member reservoirs had medium-low porosity and low permeability, and, locally, medium-high porosity and medium permeability. Affected by the development of mound-shoal complex and heterogeneous dissolution, the platform margin along Ningqiang, Guangyuan, Jiange and Langzhong is the most favorable region for reservoir development. Deep buried Dengying Formation in the guangyuan and langzhong areas should be the most important hydrocarbon target for the future exploration.
基金Supported by the Central Guiding Local Science and Technology Development Special Project(ZY20B13)。
文摘By conducting experimental analyses, including thermal pyrolysis, micro-/nano-CT, argon-ion polishing field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and two-dimensional nuclear magnetic resonance (2D NMR), the Gulong shale oil in the Songliao Basin was investigated with respect to formation model, pore structure and accumulation mechanism. First, in the Gulong shale, there are a large number of pico-algae, nano-algae and dinoflagellates, which were formed in brackish water environment and constituted the hydrogen-rich oil source materials of shale. Second, most of the oil-generating materials of the Qingshankou Formation shale exist in the form of organo-clay complex. During organic matter thermal evolution, clay minerals had double effects of suppression and catalytic hydrogenation, which expanded shale oil window and increased light hydrocarbon yield. Third, the formation of storage space in the Gulong Shale was related to dissolution and hydrocarbon generation. With the diagenesis, micro-/nano-pores increased, pore diameter decreased and more bedding fractures appeared, which jointly gave rise to the unique reservoir with dual media (i.e. nano-scale pores and micro-scale bedding fractures) in the Gulong shale. Fourth, the micro-/nano-scale oil storage unit in the Gulong shale exhibits independent oil/gas occurrence phase, and shows that all-size pores contain oils, which occur in condensate state in micropores or in oil-gas two phase (or liquid) state in macropores/mesopores. The understanding about Gulong shale oil formation and accumulation mechanism has theoretical and practical significance for advancing continental shale oil exploration in China.
基金supported by the National Natural Science Foundation of China(No.41972145)National Science and Technology Major Project of China(No.2017ZX05035—002)+1 种基金the Foundation(No.PRP/indep-2-1904,PRP/indep-3-1707 and No.PRP/indep-3-1615)of State Key Laboratory of Petroleum Resources and Prospecting from China University of Petroleum in Beijingfundamental Research Funds for China University of Geosciences under Award Number 35832019035。
文摘The water adsorption by shale significantly affects shale gas content and its seepage capacity.However,the mechanism of water adsorption by shale is still unclear due to its strong heterogeneity and complicated pore structure.The relationship between the adsorbed water content at different relative humidities(RHs)and shale compositions,as well as shale pore structure and the spatial configuration relationship between organic matter(OM)and clay minerals,was investigated to clarify the controlling factors and mechanisms of water adsorption by Longmaxi Formation shale from the Southern Sichuan Basin in China.Consequently,the water adsorption process could be generally divided into three different stages from 0%RH to 99%RH.Furthermore,the Johnston’s clay mine ral interlayer pore structure model(JCM),the Freundlich model(FM)and the Dubinin-Astakhov model(DAM)were tested to fit the three water adsorption stages from low RH to high RH,respectively.The fitting results of the JCM and FM at lower RHs were far from good,while the fitting results of DAM at higher RHs were acceptable.Accordingly,two revised models(LRHM and MRHM)considering the spatial configuration relationship between OM and clay minerals were proposed for the two stages with lower RHs,and performed better fitting results indicating the pronounced effect of the spatial configuration relationship between OM and clay minerals on the water adsorption process of Longmaxi Formation shale.The outcomes of this study will contribute to clarifying the water distribution characteristics in the pore network of shale samples with variable water contents.
基金Supported by the Science and Technology Project of PetroChina (2021DJ0605)。
文摘Based on the seismic, logging, drilling and other data, the distribution, structural types and mound-shoal hydrocarbon accumulation characteristics of platform margins of the Sinian Dengying Formation in the Deyang-Anyue Rift and its periphery were analyzed. Four types of platform margins are developed in the Dengying Formation, i.e., single-stage fault-controlled platform margin, multi-stage fault-controlled platform margin, gentle slope platform margin, and overlapping platform margin. In the Gaoshiti West-Weiyuan East area, single-stage fault controlled platform margins are developed in the Deng 2 Member, which trend in nearly NEE direction and are shielded by faults and mudstones, forming fault-controlled–lithologic traps. In the Lezhi-Penglai area, independent and multi-stage fault controlled platform margins are developed in the Deng 2 Member, which trend in NE direction and are controlled by synsedimentary faults;the mound-shoal complexes are aggraded and built on the hanging walls of the faults, and they are shielded by tight intertidal belts and the Lower Cambrian source rocks in multiple directions, forming fault-controlled–lithologic and other composite traps. In the Weiyuan-Ziyang area, gentle slope platform margins are developed in the Deng 2 Member, which trend in NW direction;the mound-shoal complexes are mostly thin interbeds as continuous bands and shielded by tight intertidal belts in the updip direction, forming lithologic traps. In the Gaoshiti-Moxi-Yanting area, overlapping platform margins are developed in the Deng 2 and Deng 4 members;the mound-shoal complexes are aggraded and overlaid to create platform margin buildup with a huge thickness and sealed by tight intertidal belts and the Lower Cambrian mudstones in the updip direction, forming large-scale lithologic traps on the north slope of the Central Sichuan Paleouplift. To summarize, the mound-shoal complexes on the platform margins in the Dengying Formation in the Penglai-Zhongjiang area, Moxi North-Yanting area and Weiyuan-Ziyang area are large in scale, with estimated resources of 1.58×1012 m3, and they will be the key targets for the future exploration of the Dengying Formation in the Sichuan Basin.
基金financial support of this work by the Swedish Research Council(2017-00935)Swedish Energy Agency and Knut and Alice Wallenberg Foundation(KAW 2016.0072)。
文摘Numerous aspects of the water oxidation mechanism in photosystemⅡhave not been fully elucidated,especially the O-O bond formation pathway.However,a body of experimental evidences have identified the O5 and W2 ligands of the oxygen-evolving complex as the highly probable substrate candidates.In this work,we studied O-O bond formation between O5 and W2 based on the native Mn4 Ca cluster by density functional calculations.Structural rearrangements before the formation of the S_(4) state were found as a prerequisite for O-O bond formation between O5 and W2,regardless if the suggested pathways involving the typical Mnl(Ⅳ)-O·species or the recently proposed Mn4(Ⅶ)(O)2 species.Possible alternatives for the S2→S_(3) and S_(3)→S_(4) transitions accounting for such required rearrangements are discussed.These findings reflect that the structural flexibility of the Mn4 Ca cluster is essential to allow structural rearrangements during the catalytic cycle.
基金the National Natural Science Foundation of China (41674131,41574118,41974146,41904109)the Fundamental Research Funds for the Central Universities (17CX06041,17CX06044)the China National Science and Technology Major Project (2016ZX05007-004,2017ZX05072-002)
文摘Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/electric fields in 2D formations efficiently by the 2.5D finite diff erence method.Particularly,by leveraging the field’s rapid attenuation in spectral domain,we propose truncated Gauss–Hermite quadrature,which is several tens of times faster than traditional inverse fast Fourier transform.By applying the algorithm to the LWD modeling under complex formations,e.g.,folds,fault and sandstone pinch-outs,we analyze the feasibility of the dimension reduction from 2D to 1D.For the formations with smooth lateral changes,like folds,the simplified 1D model’s results agree well with the true responses,which indicate that the 1D simplification with sliding window is feasible.However,for the formation structures with drastic rock properties changes and sharp boundaries,for instance,faults and sandstone pinch-outs,the simplified 1D model will lead to large errors and,therefore,2.5D algorithms should be applied to ensure the accuracy.
基金supported by the Program for New Century Excellent Talents in Universities
文摘In order to obtain effective parameters for complex sand reservoirs,a log evaluation method for relevant reservoir parameters is established based on an analysis in the gas-bearing sandstone with high porosity and low permeability,low porosity and permeability and on various characteristics of log responses to reservoir lithologies and physical properties in the Neopleozoic sand reservoir of the Ordos basin.This log evaluation method covers the Cook method that is used to evaluate the porosity and oiliness in high porosity and low permeability reservoirs and another method in which the mineral content,derived from geochemical logs,is used to identify formation lithologies.Some areas have high calcium and low silt content,not uniformly distributed,the results of which show up in the complex formation lithologies and conventional log responses with great deviation.The reliability of the method is verified by comparison with conventional log data and core analyses.The calculation results coincide with the core analytical data and gas tests,which indicate that this log evaluation method is available,provides novel ideas for study of similar complex reservoir lithologies and has some reference value.
基金supported by the General Program of National Natural Science Foundation of China(32072237)the Hubei Provincial Natural Science Foundation of China(2020CFB583)Fundamental Research Funds for the Central Universities(2662020SPPY006)。
文摘Phosvitin(PV)was treated with high-temperature,mild pressure(HTMP),and enzyme combination,and then phosvitin phosphopeptides-calcium(PPP-Ca)complexes were prepared.The low-calcium specific pathogen free-Kunming(SPF-KM)mice were used to determine the effect of PPP-Ca complexes on intestinal calcium absorption and their utilization for bone formation.The serum calcium content was the highest with the HTMP-Enz-PPP-Ca treatment(2.19 mmol/L),and it significantly down-regulated the abnormal elevation of serum alkaline phosphatase(AKP)caused by calcium deficiency.The low-calcium control group had the lowest calcium deposited to the femur(80.41 mg/g)and the lowest femur bone mineral density(BMD)(0.17 g/cm^(3)),while HTMP-Enz-PPP-Ca significantly improved bone calcium content(94.33 mg/g)and BMD(0.29 g/cm^(3)).The micro-computed tomography(MCT)images showed that the femur with the normal control,PV-Ca,and HTMP-Enz-PPP-Ca treatments had a more compact,complete,and thicker trabecular network than the low-calcium and CaCl_(2)treatments.These results indicated that the organic calcium(HTMP-Enz-PPP-Ca)promoted calcium absorption and bone deposition,and the effect of HTMP-Enz-PPP-Ca was better than the inorganic CaCl_(2).
