The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas resources.The sedimentary environment plays a vital role in the formation of organic-ric...The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas resources.The sedimentary environment plays a vital role in the formation of organic-rich sediments in lacustrine facies.This article unravels the mineralogy,geochemistry,and paleoenvironmental evolution during the deposition of the Paleogene Shahejie Formation(Es_(3)^(L)).It discusses the effects of paleoclimate,paleosalinity,paleoredox conditions,paleowater depth,and paleoproductivity on organic matter(OM)enrichment.Finally,the OM enrichment model was established.The results show that the mineralogical compositions are mainly composed of calcite(avg.40.13%),quartz(avg.21.64%)and clay minerals(avg.24.07%),accompanied by dolomite(avg.7.07%),feldspar(avg.6.36%)and pyrite(avg.2.95%).The Es_(3)^(L) shale has a high abundance of OM,with total organic carbon(TOC)ranging from 1.07%to 5.12%.The organic matter type is mainly composed of type I-II_(1) kerogen,which is generally considered a good-quality source rock.The source of OM is a mixture of lower bacteria,algae,and plants.During the early sedimentary period,the paleoclimate was dry and cold,with high salinity,intense reducibility,and relatively low productivity.During the late sedimentary period,the climate became warmer and more humid.As a result,the salinity decreased to a level that was suitable for biological reproduction,and productivity increased gradually due to the input of terrigenous plants.Paleosalinity and paleoclimate determined the environment of the sedimentary period,in addition,paleoproductivity and paleoredox condition indicated the formation and preservation conditions of OM.The warm and humid climate,brackish water,suitable reduction conditions and high productivity are the favorable conditions for the generation and preservation of organic matter.The research results may have implications for the genetic mechanisms of organic matter accumulation.They will provide theoretical and technical insights into the exploration and development of shale oil.展开更多
预期功能安全的提出,使得传统的自动紧急制动系统的安全性受到了挑战。为此,本文中利用基于系统理论过程分析(systems-theoretic process analysis,STPA)方法得到了自动紧急制动系统的预期功能安全要求,在传统的自动紧急制动系统基础上...预期功能安全的提出,使得传统的自动紧急制动系统的安全性受到了挑战。为此,本文中利用基于系统理论过程分析(systems-theoretic process analysis,STPA)方法得到了自动紧急制动系统的预期功能安全要求,在传统的自动紧急制动系统基础上增加了感知盲区安全车速规划策略。然后基于盲区场景下车辆与行人相遇运动学模型,构造盲区安全车速公式。接着设计加入非线性干扰观测器的速度滑模控制器,对该速度进行跟踪控制,最后在CarSim与Simulink联合平台上开展仿真试验,比较此系统与没有增加预期功能安全要求的自动紧急制动系统的安全性,并进一步在硬件在环仿真试验台上验证。结果表明,考虑预期功能安全的自动紧急制动系统能有效降低行人碰撞风险,并确保车辆安全通过盲区的行驶效率。展开更多
Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oi...Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.展开更多
Core,thin section,conventional and image logs are used to provide insights into distribution of fractures in fine grained sedimentary rocks of Permian Lucaogou Formation in Jimusar Sag.Bedding parallel fractures are c...Core,thin section,conventional and image logs are used to provide insights into distribution of fractures in fine grained sedimentary rocks of Permian Lucaogou Formation in Jimusar Sag.Bedding parallel fractures are common in fine grained sedimentary rocks which are characterized by layered structures.Core and thin section analysis reveal that fractures in Lucaogou Formation include tectonic inclined fracture,bedding parallel fracture,and abnormal high pressure fracture.Bedding parallel fractures are abundant,but only minor amounts of them remain open,and most of them are partly to fully sealed by carbonate minerals(calcite)and bitumen.Bedding parallel fractures result in a rapid decrease in resistivity,and they are recognized on image logs to extend along bedding planes and have discontinuous surfaces due to partly-fully filled resistive carbonate minerals as well as late stage dissolution.A comprehensive interpretation of distribution of bedding parallel fractures is performed with green line,red line,yellow line and blue line representing bedding planes,induced fractures,resistive fractures,and open(bedding and inclined)fractures,respectively.The strike of bedding parallel fractures is coinciding with bedding planes.Bedding parallel fractures are closely associated with the amounts of bedding planes,and high density of bedding planes favor the formation of bedding parallel fractures.Alternating dark and bright layers have the most abundant bedding parallel fractures on the image logs,and the bedding parallel fractures are always associated with low resistivity zones.The results above may help optimize sweet spots in fine grained sedimentary rocks,and improve future fracturing design and optimize well spacing.展开更多
OBJECTIVE Urocortins(UCNs)and transforming growth factor-β(TGF-β)have been demonstrated to participate in various cardiovascular diseases,many of which involve VSMCs proliferation.And cytosolic phospholipase A2(c PL...OBJECTIVE Urocortins(UCNs)and transforming growth factor-β(TGF-β)have been demonstrated to participate in various cardiovascular diseases,many of which involve VSMCs proliferation.And cytosolic phospholipase A2(c PLA2)-mediated arachidonic acid(AA)release is an important cause of vascular smooth muscle cells(VSMCs)proliferation.The work was to investigate the regulation of VSMCs proliferation by UCN/TGF-βand whether c PLA2 was a link between their signaling pathways.METHODS VSMC proliferation was measured by MTT assay and immunofluorescence microscopy.Using cell flow cytometry,the changes in the cell cycle phases were investigated.si RNA was used to knockdown Smad2 and smad3 genes.Lentiviral Vector Particle was performed to over express c PLA2 gene.RESULTS Both UCN and TGF-βinhibited VSMCs proliferation and an additive effect was observed when the cells were treated with UCN plus TGF-β.TGF-βincreased the percentage of cells in G1-phase while UCN increased the cell percentage in G2-phase with a concomitant decrease in S-phase.Neither knockdown of smad2 nor smad3 reversed the role of TGF-β.Furthermore,c PLA2expression was increased by TGF-βbut decreased by UCN and UCN attenuated TGF-β-induced c PLA2 expression.In primary VSMCs,TGF-βinduced c PLA2 phosphorylation,and this effect was also attenuated by UCN.Similar to UCN,the c PLA2 inhibitor,pyrrophenone(PYR),also played a role in enhancing TGF-β-mediated mitoinhibition.Inversely,over-expression of c PLA2 eliminated the effect of UCN on the mitoinhibition.CONCLUSION The pretreatment with UCN counteracted TGF-β-mediated c PLA2 expression and activation,thereby contributing to TGF-β-mediated mitoinhibition of VSMCs.展开更多
Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin,China,to investigate the impact of hydrocarbon generation on shale pore structure evolution.Thermal evolution ...Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin,China,to investigate the impact of hydrocarbon generation on shale pore structure evolution.Thermal evolution is found to control the transformation of organic matter,hydrocarbon products characteristics,and pore structure changes.Furthermore,pore volume and specific surface area increase with increasing maturity.In low-mature stage,the retained oil content begins to increase,pore volumes show slight changes,and primary pores are occluded by the generated crude oil of high molecular weight and density.In the oil-window stage,the retained oil content rapidly increases and reaches maximum,and pore volumes gradually increase with increasing thermal maturity.At high mature stage,the retained oil content begins to decrease,and the pore volume increases considerably owing to the expulsion of liquid hydrocarbon.In over mature stage,natural gas content significantly increases and kerogen transforms to asphalt.Numerous organic pores are formed and the pore size gradually increases,resulting from the connection of organic pores caused the increasing thermal stress.This study lays a foundation for understanding variation of hydrocarbon products during the thermal evolution of lacustrine shales and its relationship with the evolution of shale reservoirs.展开更多
Geophysical well logs are widely used in geological fields,however,there are considerable incompatibilities existing in solving geological issues using well log data.This review critically fills the gaps between geolo...Geophysical well logs are widely used in geological fields,however,there are considerable incompatibilities existing in solving geological issues using well log data.This review critically fills the gaps between geology and geophysical well logs,as assessed from peer reviewed papers and from the authors’personal experiences,in the particular goal of solving geological issues using geophysical well logs.The origin and history of geophysical logging are summarized.Next follows a review of the state of knowledge for geophysical well logs in terms of type of specifications,vertical resolution,depth of investigations and demonstrated applications.Then the current status and advances in applications of geophysical well logs in fields of structural geology,sedimentary geology and petroleum geology are discussed.Well logs are used in structural and sedimentary geology in terms of structure detection,in situ stress evaluation,sedimentary characterization,sequence stratigraphy division and fracture prediction.Well logs can also be applied in petroleum geology fields of optimizing sweet spots for hydraulic fracturing in unconventional oil and gas resource.Geophysical well logs are extending their application in other fields of geosciences,and geological issues will be efficiently solved via well logs with the improvements of advanced well log suits.Further work is required in order to improve accuracy and diminish uncertainties by introducing artificial intelligence.This review provides a systematic and clear descriptions of the applications of geophysical well log data along with examples of how the data is displayed and processed for solving geologic problems.展开更多
Knowledge of how high can fracture porosity become in the ultra-deep burial conditions is important but remains problematic.Fracture aperture and porosity are measured using X-ray computed tomography(CT)at atmospheric...Knowledge of how high can fracture porosity become in the ultra-deep burial conditions is important but remains problematic.Fracture aperture and porosity are measured using X-ray computed tomography(CT)at atmospheric pressure and then calculated by image logs.Special attention is paid to how high fracture porosity can become in ultra-deep(>6000 m)settings,and which situations will result in high fracture porosities.In situ stress magnitudes,which can be calculated using well logs,control fracture performances,and dissolution along fracture improve fracture porosity at ultra-deep burial depths.Low horizontal stress difference(Dr<25 MPa),very high fracture density will result in a high fracture porosity.Fracture porosity can keep as high as 2.0%in relatively low in situ stress conditions even at ultra-deep burial depths.In intense in situ stress conditions(Dr>45 MPa),a high degree of dissolution along the fracture dramatically increases fracture porosity.Dissolution will result in the vuggy fracture planes and improve fracture porosity up to 2.0%.The results provide insights into the detection,characterization,and modeling of subsurface fractures.展开更多
Diagenesis exerts an important control on porosity evolution,and research of diagenesis and diagenetic minerals provides insights into reservoir quality evaluation and CO_(2) storage.Thin section,XRD(X-ray diffraction...Diagenesis exerts an important control on porosity evolution,and research of diagenesis and diagenetic minerals provides insights into reservoir quality evaluation and CO_(2) storage.Thin section,XRD(X-ray diffraction),CT(Computed Tomography),scanning electron microscopy(SEM),and NMR(Nuclear Magnetic Resonance)tests were used to investigate composition,texture,pore spaces,and diagenesis of sandstones in Paleogene Dongying Formation in Bohai Bay Basin,China,with special aims to unravel diagentic dissolution along bedding planes.The oversized pores,remnants in feldspar-hosted pores,and kaolinite within feldspar grains indicate a high degree of dissolution the framework grains experienced during burial.The CO_(2)-rich or organic acids are responsible for the feldspar dissolution.Grain size plays the primary role in enhancing bedding dissolution process,and bedding planes in fine-medium grained sandstones with high content of feldspars are frequently enlarged by dissolution.The CT scanning image confirms dissolution pores are distributed discontinuously along the bedding planes.The dissolution pores along bedding planes have large pore size,and correspond to the right peak of the bi-modal T_(2)(transverse relaxation time)spectrum.The laminated sandstones and siltstones,or sandstones with cross beddings help improve framework grain dissolution.These new findings help improve the understanding of diagenetic models,and have implications in reservoir quality prediction and resource assessments in sandstones.展开更多
Objectives:Previous studies demonstrated that endometriosis and adenomyosis are closely linked to lots of adverse pregnancy outcomes while the role of endometriosis in pregnant women with adenomyosis has not been expl...Objectives:Previous studies demonstrated that endometriosis and adenomyosis are closely linked to lots of adverse pregnancy outcomes while the role of endometriosis in pregnant women with adenomyosis has not been explored yet.The present study aimed to evaluate the influence of previous laparoscopic surgical and pathological diagnosis of endometriosis on pregnancy outcomes in women with adenomyosis.Methods:A total of 60 pregnant women who were diagnosed with adenomyosis before or during pregnancy were included in this study.Among them,8 were also diagnosed with endometriosis by previous laparoscopic surgery.The demographic characteristics and pregnancy outcomes were compared between women with adenomyosis only and those with the surgical history of endometriosis.Results:Compared with women with adenomyosis only,those concomitant with the surgical history of endometriosis had significantly higher age at delivery[37.5(36.25–39.75)vs.35(33.25–37),P=0.016]and an increased risk of postpartum hemorrhage(PPH)(adjusted OR:5.992,95%CI:1.03–34.857,P=0.046)while no significant differences were found in other adverse pregnancy outcomes between these two groups.Then we further detected the risk factor of PPH in women with adenomyosis and found that the surgical history of endometriosis(OR:6.995,95%CI:1.16–42.171,P=0.034)and assisted reproductive technology(ART)(OR:5.062,95%CI:1.494–17.146,P=0.009)were the parameters closely associated with the occurrence of PPH.Conclusions:The history of previous laparoscopic surgical and pathological diagnosis of endometriosis in pregnant women with adenomyosis may increase the risk of PPH,which still needs to be verified by future studies with a large sample size.Besides,pregnancy through ART is also an increased risk factor for PPH in women with adenomyosis.Pregnant women with adenomyosis who conceived with the surgical history of endometriosis or by ART should be closely monitored for the reason of being at high risk of PPH.展开更多
基金supported by the National Natural Science Foundation of China(No.42272110)。
文摘The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas resources.The sedimentary environment plays a vital role in the formation of organic-rich sediments in lacustrine facies.This article unravels the mineralogy,geochemistry,and paleoenvironmental evolution during the deposition of the Paleogene Shahejie Formation(Es_(3)^(L)).It discusses the effects of paleoclimate,paleosalinity,paleoredox conditions,paleowater depth,and paleoproductivity on organic matter(OM)enrichment.Finally,the OM enrichment model was established.The results show that the mineralogical compositions are mainly composed of calcite(avg.40.13%),quartz(avg.21.64%)and clay minerals(avg.24.07%),accompanied by dolomite(avg.7.07%),feldspar(avg.6.36%)and pyrite(avg.2.95%).The Es_(3)^(L) shale has a high abundance of OM,with total organic carbon(TOC)ranging from 1.07%to 5.12%.The organic matter type is mainly composed of type I-II_(1) kerogen,which is generally considered a good-quality source rock.The source of OM is a mixture of lower bacteria,algae,and plants.During the early sedimentary period,the paleoclimate was dry and cold,with high salinity,intense reducibility,and relatively low productivity.During the late sedimentary period,the climate became warmer and more humid.As a result,the salinity decreased to a level that was suitable for biological reproduction,and productivity increased gradually due to the input of terrigenous plants.Paleosalinity and paleoclimate determined the environment of the sedimentary period,in addition,paleoproductivity and paleoredox condition indicated the formation and preservation conditions of OM.The warm and humid climate,brackish water,suitable reduction conditions and high productivity are the favorable conditions for the generation and preservation of organic matter.The research results may have implications for the genetic mechanisms of organic matter accumulation.They will provide theoretical and technical insights into the exploration and development of shale oil.
文摘预期功能安全的提出,使得传统的自动紧急制动系统的安全性受到了挑战。为此,本文中利用基于系统理论过程分析(systems-theoretic process analysis,STPA)方法得到了自动紧急制动系统的预期功能安全要求,在传统的自动紧急制动系统基础上增加了感知盲区安全车速规划策略。然后基于盲区场景下车辆与行人相遇运动学模型,构造盲区安全车速公式。接着设计加入非线性干扰观测器的速度滑模控制器,对该速度进行跟踪控制,最后在CarSim与Simulink联合平台上开展仿真试验,比较此系统与没有增加预期功能安全要求的自动紧急制动系统的安全性,并进一步在硬件在环仿真试验台上验证。结果表明,考虑预期功能安全的自动紧急制动系统能有效降低行人碰撞风险,并确保车辆安全通过盲区的行驶效率。
基金National Natural Science Foundation of China(Grant No.42002133,42072150)Science Foundation of China University of Petroleum,Beijing(No.2462021YXZZ003)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01-06)for the financial supports and permissions to publish this paper
文摘Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.
基金financially supported by the National Natural Science Foundation of China(No.42002133,42072150)Natural Science Foundation of Beijing(8204069)+1 种基金Strategic Cooperation Project of PetroChina and CUPB(ZLZX2020-01-06-01)Science Foundation of China University of Petroleum,Beijing(No.2462021YXZZ003)
文摘Core,thin section,conventional and image logs are used to provide insights into distribution of fractures in fine grained sedimentary rocks of Permian Lucaogou Formation in Jimusar Sag.Bedding parallel fractures are common in fine grained sedimentary rocks which are characterized by layered structures.Core and thin section analysis reveal that fractures in Lucaogou Formation include tectonic inclined fracture,bedding parallel fracture,and abnormal high pressure fracture.Bedding parallel fractures are abundant,but only minor amounts of them remain open,and most of them are partly to fully sealed by carbonate minerals(calcite)and bitumen.Bedding parallel fractures result in a rapid decrease in resistivity,and they are recognized on image logs to extend along bedding planes and have discontinuous surfaces due to partly-fully filled resistive carbonate minerals as well as late stage dissolution.A comprehensive interpretation of distribution of bedding parallel fractures is performed with green line,red line,yellow line and blue line representing bedding planes,induced fractures,resistive fractures,and open(bedding and inclined)fractures,respectively.The strike of bedding parallel fractures is coinciding with bedding planes.Bedding parallel fractures are closely associated with the amounts of bedding planes,and high density of bedding planes favor the formation of bedding parallel fractures.Alternating dark and bright layers have the most abundant bedding parallel fractures on the image logs,and the bedding parallel fractures are always associated with low resistivity zones.The results above may help optimize sweet spots in fine grained sedimentary rocks,and improve future fracturing design and optimize well spacing.
基金The project supported by National Natural Science Foundation of China(81573424&81273510)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘OBJECTIVE Urocortins(UCNs)and transforming growth factor-β(TGF-β)have been demonstrated to participate in various cardiovascular diseases,many of which involve VSMCs proliferation.And cytosolic phospholipase A2(c PLA2)-mediated arachidonic acid(AA)release is an important cause of vascular smooth muscle cells(VSMCs)proliferation.The work was to investigate the regulation of VSMCs proliferation by UCN/TGF-βand whether c PLA2 was a link between their signaling pathways.METHODS VSMC proliferation was measured by MTT assay and immunofluorescence microscopy.Using cell flow cytometry,the changes in the cell cycle phases were investigated.si RNA was used to knockdown Smad2 and smad3 genes.Lentiviral Vector Particle was performed to over express c PLA2 gene.RESULTS Both UCN and TGF-βinhibited VSMCs proliferation and an additive effect was observed when the cells were treated with UCN plus TGF-β.TGF-βincreased the percentage of cells in G1-phase while UCN increased the cell percentage in G2-phase with a concomitant decrease in S-phase.Neither knockdown of smad2 nor smad3 reversed the role of TGF-β.Furthermore,c PLA2expression was increased by TGF-βbut decreased by UCN and UCN attenuated TGF-β-induced c PLA2 expression.In primary VSMCs,TGF-βinduced c PLA2 phosphorylation,and this effect was also attenuated by UCN.Similar to UCN,the c PLA2 inhibitor,pyrrophenone(PYR),also played a role in enhancing TGF-β-mediated mitoinhibition.Inversely,over-expression of c PLA2 eliminated the effect of UCN on the mitoinhibition.CONCLUSION The pretreatment with UCN counteracted TGF-β-mediated c PLA2 expression and activation,thereby contributing to TGF-β-mediated mitoinhibition of VSMCs.
基金supported by the National Natural Science Foundation of China(Grant Nos.42072150,41372144)the State Science and Technology Major Project of China(Grant No.2017ZX05049001-008)
文摘Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin,China,to investigate the impact of hydrocarbon generation on shale pore structure evolution.Thermal evolution is found to control the transformation of organic matter,hydrocarbon products characteristics,and pore structure changes.Furthermore,pore volume and specific surface area increase with increasing maturity.In low-mature stage,the retained oil content begins to increase,pore volumes show slight changes,and primary pores are occluded by the generated crude oil of high molecular weight and density.In the oil-window stage,the retained oil content rapidly increases and reaches maximum,and pore volumes gradually increase with increasing thermal maturity.At high mature stage,the retained oil content begins to decrease,and the pore volume increases considerably owing to the expulsion of liquid hydrocarbon.In over mature stage,natural gas content significantly increases and kerogen transforms to asphalt.Numerous organic pores are formed and the pore size gradually increases,resulting from the connection of organic pores caused the increasing thermal stress.This study lays a foundation for understanding variation of hydrocarbon products during the thermal evolution of lacustrine shales and its relationship with the evolution of shale reservoirs.
基金supported by National Natural Science Foundation of China(Grant No.42002133)strategic cooperation project of PetroChina and CUPB(China University of Petroleum,Beijing)(ZLZX2020-01)Science Foundation of China University of Petroleum,Beijing(No.2462023QNXZ010).
文摘Geophysical well logs are widely used in geological fields,however,there are considerable incompatibilities existing in solving geological issues using well log data.This review critically fills the gaps between geology and geophysical well logs,as assessed from peer reviewed papers and from the authors’personal experiences,in the particular goal of solving geological issues using geophysical well logs.The origin and history of geophysical logging are summarized.Next follows a review of the state of knowledge for geophysical well logs in terms of type of specifications,vertical resolution,depth of investigations and demonstrated applications.Then the current status and advances in applications of geophysical well logs in fields of structural geology,sedimentary geology and petroleum geology are discussed.Well logs are used in structural and sedimentary geology in terms of structure detection,in situ stress evaluation,sedimentary characterization,sequence stratigraphy division and fracture prediction.Well logs can also be applied in petroleum geology fields of optimizing sweet spots for hydraulic fracturing in unconventional oil and gas resource.Geophysical well logs are extending their application in other fields of geosciences,and geological issues will be efficiently solved via well logs with the improvements of advanced well log suits.Further work is required in order to improve accuracy and diminish uncertainties by introducing artificial intelligence.This review provides a systematic and clear descriptions of the applications of geophysical well log data along with examples of how the data is displayed and processed for solving geologic problems.
基金supported by National Natural Science Foundation of China(Grant No.42002133)Strategic Cooperation Project of PetroChina and China University of Petroleum,Beijing(CUPB)(Grant No.ZLZX2020-01-05)Science Foundation of CUPB(Grant No.2462021YXZZ003).
文摘Knowledge of how high can fracture porosity become in the ultra-deep burial conditions is important but remains problematic.Fracture aperture and porosity are measured using X-ray computed tomography(CT)at atmospheric pressure and then calculated by image logs.Special attention is paid to how high fracture porosity can become in ultra-deep(>6000 m)settings,and which situations will result in high fracture porosities.In situ stress magnitudes,which can be calculated using well logs,control fracture performances,and dissolution along fracture improve fracture porosity at ultra-deep burial depths.Low horizontal stress difference(Dr<25 MPa),very high fracture density will result in a high fracture porosity.Fracture porosity can keep as high as 2.0%in relatively low in situ stress conditions even at ultra-deep burial depths.In intense in situ stress conditions(Dr>45 MPa),a high degree of dissolution along the fracture dramatically increases fracture porosity.Dissolution will result in the vuggy fracture planes and improve fracture porosity up to 2.0%.The results provide insights into the detection,characterization,and modeling of subsurface fractures.
基金supported by Natural Science Foundation of Beijing(No.8204069)Science Foundation of China University of Petroleum,Beijing(No.2462021YXZZ003).
文摘Diagenesis exerts an important control on porosity evolution,and research of diagenesis and diagenetic minerals provides insights into reservoir quality evaluation and CO_(2) storage.Thin section,XRD(X-ray diffraction),CT(Computed Tomography),scanning electron microscopy(SEM),and NMR(Nuclear Magnetic Resonance)tests were used to investigate composition,texture,pore spaces,and diagenesis of sandstones in Paleogene Dongying Formation in Bohai Bay Basin,China,with special aims to unravel diagentic dissolution along bedding planes.The oversized pores,remnants in feldspar-hosted pores,and kaolinite within feldspar grains indicate a high degree of dissolution the framework grains experienced during burial.The CO_(2)-rich or organic acids are responsible for the feldspar dissolution.Grain size plays the primary role in enhancing bedding dissolution process,and bedding planes in fine-medium grained sandstones with high content of feldspars are frequently enlarged by dissolution.The CT scanning image confirms dissolution pores are distributed discontinuously along the bedding planes.The dissolution pores along bedding planes have large pore size,and correspond to the right peak of the bi-modal T_(2)(transverse relaxation time)spectrum.The laminated sandstones and siltstones,or sandstones with cross beddings help improve framework grain dissolution.These new findings help improve the understanding of diagenetic models,and have implications in reservoir quality prediction and resource assessments in sandstones.
基金supported by“Natural Science Foundation of Beijing Municipality”[No:7222206].
文摘Objectives:Previous studies demonstrated that endometriosis and adenomyosis are closely linked to lots of adverse pregnancy outcomes while the role of endometriosis in pregnant women with adenomyosis has not been explored yet.The present study aimed to evaluate the influence of previous laparoscopic surgical and pathological diagnosis of endometriosis on pregnancy outcomes in women with adenomyosis.Methods:A total of 60 pregnant women who were diagnosed with adenomyosis before or during pregnancy were included in this study.Among them,8 were also diagnosed with endometriosis by previous laparoscopic surgery.The demographic characteristics and pregnancy outcomes were compared between women with adenomyosis only and those with the surgical history of endometriosis.Results:Compared with women with adenomyosis only,those concomitant with the surgical history of endometriosis had significantly higher age at delivery[37.5(36.25–39.75)vs.35(33.25–37),P=0.016]and an increased risk of postpartum hemorrhage(PPH)(adjusted OR:5.992,95%CI:1.03–34.857,P=0.046)while no significant differences were found in other adverse pregnancy outcomes between these two groups.Then we further detected the risk factor of PPH in women with adenomyosis and found that the surgical history of endometriosis(OR:6.995,95%CI:1.16–42.171,P=0.034)and assisted reproductive technology(ART)(OR:5.062,95%CI:1.494–17.146,P=0.009)were the parameters closely associated with the occurrence of PPH.Conclusions:The history of previous laparoscopic surgical and pathological diagnosis of endometriosis in pregnant women with adenomyosis may increase the risk of PPH,which still needs to be verified by future studies with a large sample size.Besides,pregnancy through ART is also an increased risk factor for PPH in women with adenomyosis.Pregnant women with adenomyosis who conceived with the surgical history of endometriosis or by ART should be closely monitored for the reason of being at high risk of PPH.
