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
This study took the Gulong Shale in the Upper Cretaceous Qingshankou Formation of the Songliao Basin,NE China,as an example.Through paleolake-level reconstruction and comprehensive analyses on types of lamina,vertical...This study took the Gulong Shale in the Upper Cretaceous Qingshankou Formation of the Songliao Basin,NE China,as an example.Through paleolake-level reconstruction and comprehensive analyses on types of lamina,vertical associations of lithofacies,as well as stages and controlling factors of sedimentary evolution,the cyclic changes of waters,paleoclimate,and continental clastic supply intensity in the lake basin during the deposition of the Qingshankou Formation were discussed.The impacts of lithofacies compositions/structures on oil-bearing property,the relation between reservoir performance and lithofacies compositions/structures,the differences of lithofacies in mechanical properties,and the shale oil occurrence and movability in different lithofacies were investigated.The insights of this study provide a significant guideline for evaluation of shale oil enrichment layers/zones.The non-marine shale sedimentology is expected to evolve into an interdisciplinary science on the basis of sedimentary petrology and petroleum geology,which reveals the physical,chemical and biological actions,and the distribution characteristics and evolution patterns of minerals,organic matter,pores,fluid,and phases,in the transportation,sedimentation,water-rock interaction,diagenesis and evolution processes.Such research will focus on eight aspects:lithofacies and organic matter distribution prediction under a sequence stratigraphic framework for non-marine shale strata;lithofacies paleogeography of shale strata based on the forward modeling of sedimentation;origins of non-marine shale lamina and log-based identification of lamina combinations;source of organic matter in shale and its enrichment process;non-marine shale lithofacies classification by rigid particles+plastic components+pore-fracture system;multi-field coupling organic-inorganic interaction mechanism in shale diagenesis;new methods and intelligent core technology for shale reservoir multi-scale characterization;and quantitative evaluation and intelligent analysis system of shale reservoir heterogeneity.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Supported by the National Natural Science Foundation of China(42090020,42090025)Enlisting and Leading Project of Heilongjiang Province(2021ZXJ01A09)PetroChina Scientific Research and Technological Development Project(2019E2601)。
文摘This study took the Gulong Shale in the Upper Cretaceous Qingshankou Formation of the Songliao Basin,NE China,as an example.Through paleolake-level reconstruction and comprehensive analyses on types of lamina,vertical associations of lithofacies,as well as stages and controlling factors of sedimentary evolution,the cyclic changes of waters,paleoclimate,and continental clastic supply intensity in the lake basin during the deposition of the Qingshankou Formation were discussed.The impacts of lithofacies compositions/structures on oil-bearing property,the relation between reservoir performance and lithofacies compositions/structures,the differences of lithofacies in mechanical properties,and the shale oil occurrence and movability in different lithofacies were investigated.The insights of this study provide a significant guideline for evaluation of shale oil enrichment layers/zones.The non-marine shale sedimentology is expected to evolve into an interdisciplinary science on the basis of sedimentary petrology and petroleum geology,which reveals the physical,chemical and biological actions,and the distribution characteristics and evolution patterns of minerals,organic matter,pores,fluid,and phases,in the transportation,sedimentation,water-rock interaction,diagenesis and evolution processes.Such research will focus on eight aspects:lithofacies and organic matter distribution prediction under a sequence stratigraphic framework for non-marine shale strata;lithofacies paleogeography of shale strata based on the forward modeling of sedimentation;origins of non-marine shale lamina and log-based identification of lamina combinations;source of organic matter in shale and its enrichment process;non-marine shale lithofacies classification by rigid particles+plastic components+pore-fracture system;multi-field coupling organic-inorganic interaction mechanism in shale diagenesis;new methods and intelligent core technology for shale reservoir multi-scale characterization;and quantitative evaluation and intelligent analysis system of shale reservoir heterogeneity.
