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
The report on the 20th National Congress of the Communist Party of China proposes promoting green development,advancing harmonious coexistence between humans and nature,and ensuring energy security.At COP282023,existi...The report on the 20th National Congress of the Communist Party of China proposes promoting green development,advancing harmonious coexistence between humans and nature,and ensuring energy security.At COP282023,existing climate targets were reinforced,and a fresh accord was reached for scientifically achieving net-zero carbon emission.The global energy market is being transformed,with oil and gas regaining prominence in energy security.Firms are concentrating on core competencies amidst transitions,though upstream investments show a gradual rebound.The global carbon dioxide capture and storage(CCS)projects has witnessed a significant rise,with Direct Air Capture(DAC)technology gaining attention.Carbon dioxide Capture,Utilization,and Storage(CCUS)is essential as a foundational technology for achieving dual carbon goals.In light of global future development goals and China’s national conditions,this article discusses the evolving trends in the international oil and gas sector alongside China’s domestic energy security landscape.It proposes prospective trajectories for the growth of China’s oil and gas sector and measures to guide and respond to challenges during the energy transition process,providing references for decision-making in the transformation of oil and gas companies.China has a high level of energy self-sufficiency,with the overall energy security situation remaining controllable.China’s oil and gas sector is seeing three-pronged progress:deepening exploration to 10,000s of meters,nano-level reservoir description,and reviving mature fields for a new era.Focusing on deep layer,deepwater,unconventional and mature oilfields,strengthening Belt and Road energy partnerships,enlarging reserves,optimizing pipeline network layout,implementing a smart risk-management ecosystem,and driving the CCUS technology revolution.展开更多
After the preliminary basic research on the problems encountered during the production period of Gulong shale oil in the Songliao Basin, NE China, and the scientific exploration, the special characteristics of Gulong ...After the preliminary basic research on the problems encountered during the production period of Gulong shale oil in the Songliao Basin, NE China, and the scientific exploration, the special characteristics of Gulong shale oil in terms of reservoir space, phase distribution, flow pattern, and mineral evolution are proposed. The main results are as follows :(1) The source of organic matter, mechanism of hydrocarbon generation and expulsion, and key factors affecting shale oil abundance;(2) The types and structural characteristics of the reservoir and their contribution to porosity and permeability;(3) The mineral origin and evolution of minerals and their influence on reservoir availability, sensitivity, and compressibility;(4) The rock mechanical characteristics and fracture propagation law of Gulong shale;(5) The shale oil products, phase change law and main control factors of adsorption and desorption conversion of Gulong shale oil;(6) The mechanism of shale oil-liquid, solid-liquid gas interaction and enhanced oil recovery. Three key research suggestions are proposed to realize the large-scale economic utilization of the Gulong shale oil as follows:(1) Deepen research on the mechanism of oil and gas generation and discharge, storage and transportation, to guide the selection of geological sweet spots of shale oil;(2) Deepen research on the compressibility and fracture initiation mechanism to support the selection of engineering sweet spots and optimization of engineering design;(3) Deepen research on the fluid interaction mechanism under reservoir conditions, os us to guide the optimization of development schemes and the selection of EOR technologies. A successful development of Gulong shale oil requires global experts and scholars to contribute multidisciplinary innovative ideas and technical ideas to solve production problems.展开更多
Through reviewing the development history of tight oil and gas in China,summarizing theoretical understandings in exploration and development,and comparing the geological conditions and development technologies object...Through reviewing the development history of tight oil and gas in China,summarizing theoretical understandings in exploration and development,and comparing the geological conditions and development technologies objectively in China and the United States,we clarified the progress and stage of tight oil and gas exploration and development in China,and envisaged the future development orientation of theory and technology,process methods and development policy.In nearly a decade,relying on the exploration and development practice,science and technology research and management innovation,huge breakthroughs have been made.The laws of formation,distribution and accumulation of tight oil and gas have been researched,the development theories such as"multi-stage pressure drop"and"man-made reservoirs"have been established,and several technology series have been innovated and integrated.These technology series include enrichment regions selection,well pattern deployment,single well production and recovery factor enhancement,and low cost development.As a result,both of reserves and production of tight oil and gas increase rapidly.However,limited by the sedimentary environment and tectonic background,compared with North America,China’s tight oil and gas reservoirs are worse in continuity,more difficult to develop and poorer in economic efficiency.Moreover,there are still some gaps in reservoir identification accuracy and stimulating technology between China and North America.In the future,Chinese oil and gas companies should further improve the resource evaluation method,tackle key technologies such as high-precision 3D seismic interpretation,man-made reservoir,and intelligent engineering,innovate theories and technologies to enhance single well production and recovery rate,and actively endeavor to get the finance and tax subsidy on tight oil and gas.展开更多
Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evoluti...Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution,shale oil occurrence,and pore/fracture evolution mechanism.In conjunction with a substantial amount of oil testing and production data,the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed.The results are drawn in four aspects.First,the Gulong shales are in the stage of extensive hydrocarbon expulsion when R_(0) is 1.0%-1.2%,with the peak hydrocarbon expulsion efficiency of 49.5%approximately.In the low-medium maturity stage,shale oil migrates from kerogen to rocks and organic pores/fractures.In the medium-high maturity stage,shale oil transforms from adsorbed state to free state.Second,the clay mineral intergranular pores/fractures,dissolution pores,and organic pores make up the majority of the pore structure.During the transformation,clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer.A network of pores/fractures is formed by organic matter cracking.Third,free hydrocarbon content,effective porosity,total porosity,and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers.Class-I layers are defined as free hydrocarbon content equal or greater than 6.0 mg/g,effective porosity equal or greater than 3.5%,total porosity equal or greater than 8.0%,and brittle mineral content equal or greater than 50%.It is believed that the favourable oil layers are Q2-Q3 and Q8-Q9.Fourth,the horizontal wells in the core area of the light oil zone exhibit a high cumulative production in the first year,and present a hyperbolic production decline pattern,with the decline index of 0.85-0.95,the first-year decline rate of 14.5%-26.5%,and the single-well estimated ultimate recovery(EUR)greater than 2.0×10^(4)t.In practical exploration and production,more efforts will be devoted to the clarification of hydrocarbon generation and expulsion mechanisms,accurate testing of porosity and hydrocarbon content/phase of shale under formation conditions,precise delineation of the boundary of enrichment area,relationship between mechanical properties and stimulated reservoir volume,and enhanced oil recovery,in order to improve the EUR and achieve a large-scale,efficient development of shale oil.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.
文摘The report on the 20th National Congress of the Communist Party of China proposes promoting green development,advancing harmonious coexistence between humans and nature,and ensuring energy security.At COP282023,existing climate targets were reinforced,and a fresh accord was reached for scientifically achieving net-zero carbon emission.The global energy market is being transformed,with oil and gas regaining prominence in energy security.Firms are concentrating on core competencies amidst transitions,though upstream investments show a gradual rebound.The global carbon dioxide capture and storage(CCS)projects has witnessed a significant rise,with Direct Air Capture(DAC)technology gaining attention.Carbon dioxide Capture,Utilization,and Storage(CCUS)is essential as a foundational technology for achieving dual carbon goals.In light of global future development goals and China’s national conditions,this article discusses the evolving trends in the international oil and gas sector alongside China’s domestic energy security landscape.It proposes prospective trajectories for the growth of China’s oil and gas sector and measures to guide and respond to challenges during the energy transition process,providing references for decision-making in the transformation of oil and gas companies.China has a high level of energy self-sufficiency,with the overall energy security situation remaining controllable.China’s oil and gas sector is seeing three-pronged progress:deepening exploration to 10,000s of meters,nano-level reservoir description,and reviving mature fields for a new era.Focusing on deep layer,deepwater,unconventional and mature oilfields,strengthening Belt and Road energy partnerships,enlarging reserves,optimizing pipeline network layout,implementing a smart risk-management ecosystem,and driving the CCUS technology revolution.
基金Supported by the National Natural Science Foundation of China(72088101)。
文摘After the preliminary basic research on the problems encountered during the production period of Gulong shale oil in the Songliao Basin, NE China, and the scientific exploration, the special characteristics of Gulong shale oil in terms of reservoir space, phase distribution, flow pattern, and mineral evolution are proposed. The main results are as follows :(1) The source of organic matter, mechanism of hydrocarbon generation and expulsion, and key factors affecting shale oil abundance;(2) The types and structural characteristics of the reservoir and their contribution to porosity and permeability;(3) The mineral origin and evolution of minerals and their influence on reservoir availability, sensitivity, and compressibility;(4) The rock mechanical characteristics and fracture propagation law of Gulong shale;(5) The shale oil products, phase change law and main control factors of adsorption and desorption conversion of Gulong shale oil;(6) The mechanism of shale oil-liquid, solid-liquid gas interaction and enhanced oil recovery. Three key research suggestions are proposed to realize the large-scale economic utilization of the Gulong shale oil as follows:(1) Deepen research on the mechanism of oil and gas generation and discharge, storage and transportation, to guide the selection of geological sweet spots of shale oil;(2) Deepen research on the compressibility and fracture initiation mechanism to support the selection of engineering sweet spots and optimization of engineering design;(3) Deepen research on the fluid interaction mechanism under reservoir conditions, os us to guide the optimization of development schemes and the selection of EOR technologies. A successful development of Gulong shale oil requires global experts and scholars to contribute multidisciplinary innovative ideas and technical ideas to solve production problems.
基金Supported by the China National Science and Technology Major Project(2016ZX05015,2016ZX05047,2017ZX05001).
文摘Through reviewing the development history of tight oil and gas in China,summarizing theoretical understandings in exploration and development,and comparing the geological conditions and development technologies objectively in China and the United States,we clarified the progress and stage of tight oil and gas exploration and development in China,and envisaged the future development orientation of theory and technology,process methods and development policy.In nearly a decade,relying on the exploration and development practice,science and technology research and management innovation,huge breakthroughs have been made.The laws of formation,distribution and accumulation of tight oil and gas have been researched,the development theories such as"multi-stage pressure drop"and"man-made reservoirs"have been established,and several technology series have been innovated and integrated.These technology series include enrichment regions selection,well pattern deployment,single well production and recovery factor enhancement,and low cost development.As a result,both of reserves and production of tight oil and gas increase rapidly.However,limited by the sedimentary environment and tectonic background,compared with North America,China’s tight oil and gas reservoirs are worse in continuity,more difficult to develop and poorer in economic efficiency.Moreover,there are still some gaps in reservoir identification accuracy and stimulating technology between China and North America.In the future,Chinese oil and gas companies should further improve the resource evaluation method,tackle key technologies such as high-precision 3D seismic interpretation,man-made reservoir,and intelligent engineering,innovate theories and technologies to enhance single well production and recovery rate,and actively endeavor to get the finance and tax subsidy on tight oil and gas.
基金Supported by the National Natural Science Foundation Project(42090020,42090025)Strategic Research of Oil and Gas Development Major Project of Ministry of Science and TechnologyPetroChina Scientific Research and Technological Development Project(2019E2601).
文摘Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution,shale oil occurrence,and pore/fracture evolution mechanism.In conjunction with a substantial amount of oil testing and production data,the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed.The results are drawn in four aspects.First,the Gulong shales are in the stage of extensive hydrocarbon expulsion when R_(0) is 1.0%-1.2%,with the peak hydrocarbon expulsion efficiency of 49.5%approximately.In the low-medium maturity stage,shale oil migrates from kerogen to rocks and organic pores/fractures.In the medium-high maturity stage,shale oil transforms from adsorbed state to free state.Second,the clay mineral intergranular pores/fractures,dissolution pores,and organic pores make up the majority of the pore structure.During the transformation,clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer.A network of pores/fractures is formed by organic matter cracking.Third,free hydrocarbon content,effective porosity,total porosity,and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers.Class-I layers are defined as free hydrocarbon content equal or greater than 6.0 mg/g,effective porosity equal or greater than 3.5%,total porosity equal or greater than 8.0%,and brittle mineral content equal or greater than 50%.It is believed that the favourable oil layers are Q2-Q3 and Q8-Q9.Fourth,the horizontal wells in the core area of the light oil zone exhibit a high cumulative production in the first year,and present a hyperbolic production decline pattern,with the decline index of 0.85-0.95,the first-year decline rate of 14.5%-26.5%,and the single-well estimated ultimate recovery(EUR)greater than 2.0×10^(4)t.In practical exploration and production,more efforts will be devoted to the clarification of hydrocarbon generation and expulsion mechanisms,accurate testing of porosity and hydrocarbon content/phase of shale under formation conditions,precise delineation of the boundary of enrichment area,relationship between mechanical properties and stimulated reservoir volume,and enhanced oil recovery,in order to improve the EUR and achieve a large-scale,efficient development of shale oil.
