The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling ...The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling in Chongqing.And after more than ten years of deep and careful cultivation,a series of important achievements have been obtained in the exploration and development.From the perspective of exploration and development history,theory and technology,this paper systematically summarizes the exploration discovery process and productivity construction progress of shale gas in the demonstration area,expounds the geological exploration theories and key technologies of mountain shale gas,and predicts their development prospect and direction.And the following research results are obtained.First,the exploration and development in the demonstration area has gone through five development stages,and so far,three major productivity construction zones have been formed,including Huangjinba and Zijinba middleedeep shale gas zones and Taiyang shallow shale gas zone,with cumulative proved geological reserves more than 3100×10^(8) m^(3) and cumulative gas production more than 72×10^(8) m^(3).It has been constructed into the third largest green shale gas demonstration base in China.Second,the“multi-field coordination and multi-element coupling”mountain shale gas enrichment,accumulation and occurrence theory of“sedimentary background controlling source rock and reservoir,reworking intensity controlling preservation,and three-dimensional sealing controlling enrichment”is put forward innovatively,and the“three-dimensional sealing system”accumulation model of extrabasinal shallow shale gas is established.Third,a series of zone selection and evaluation technologies for mountain shale gas in strongly reworked complex structural areas have been developed,and the concept of geologyeengineering integration has first been adopted to create transparent shale gas reservoirs and cultivate high-yield wells.A major exploration breakthrough has been achieved from marginal basin medium deep shale gas layers to extrabasin ultra shallow to medium shallow ones,and domestic first large-scale monoblock shallow shale gas field with reserves over 2570×10^(8) m^(3) has been discovered.Fourth,a landmark technological achievement and efficient development model with geologyeengineering integration and shale geomechanical evaluation as the core has been formed,which leads the clean,green and efficient exploration and development of mountain shale gas.In conclusion,it is necessary to implement the exploration strategic idea of“two outgoing”in the demonstration area,i.e.,“walking out of the stable area of the basin and marching into the complex structure areas in the Dianqianbei Depression”and“walking out of the WufengeLongmaxi Formation and exploring other layers for breakthrough”.What's more,it is recommended to carry out the double-layer stereoscopic horizontal well pattern deployment of“Leping Formation CBM(coal measure gas)þLongmaxi Formation shale gas”appropriately in a large scale,so as to establish a new integrated development model for the three-dimensional efficient development of mountain shale gas and CBM.展开更多
The lower Cambrian Qiongzhusi(Є1 q)shale in the Sichuan Basin,formerly considered a source rock,recently achieved high gas production(7.388×105 m^(3)·d^(-1))from well Z201 in the Deyang-Anyue rift trough(DAR...The lower Cambrian Qiongzhusi(Є1 q)shale in the Sichuan Basin,formerly considered a source rock,recently achieved high gas production(7.388×105 m^(3)·d^(-1))from well Z201 in the Deyang-Anyue rift trough(DART),marking an exploration breakthrough of the world’s oldest industrial shale gas reser-voir.However,the shale gas enrichment mechanism within the DART is not fully understood.This study reviews the formation of the Qiongzhusi shale gas reservoirs within the DART by comparing them with cotemporaneous deposits outside the DART,and several findings are presented.The gas production interval was correlated with the main phase of the Cambrian explosion(lower Cambrian stage 3).In the early Cambrian ecosystem,dominant animals likely accelerated the settling rates of organic matter(OM)in the upper 1st member ofЄ_(1) q(Є_(1) q_(12))by feeding on small planktonic organisms and producing larger organic fragments and fecal pellets.High primary productivity and euxinic con-ditions contributed to OM enrichment in the lower 1st member ofЄ1 q(Є_(1) q_(11)).Additionally,shale reservoirs inside the DART demonstrated better properties than those outside in terms of thickness,brittle minerals,gas content,and porosity.In particular,the abundant OM pores inside the DART facil-itated shale gas enrichment,whereas the higher thermal maturity of the shales outside the DART pos-sibly led to the graphitization and collapse of some OM pores.Meanwhile,the overpressure of high-production wells inside the DART generally reflects better shale gas preservation,benefiting from the shale’s self-sealing nature,"upper capping and lower plugging"configuration,and limited faults and microfractures.Considering these insights,we introduced a"ternary enrichment"model for the Qiongzhusi shale gas.Although the current high gas production of Z201 was found at the reservoir 3,two additional reservoirs were identified with significant potential,thus suggesting a"multilayer stereoscopic development"strategy in future shale gas exploration within the DART.展开更多
Lacustrine rift basins in China are characterized by pronounced structural segmentation,strong sedimentary heterogeneity,extensive fault-fracture development,and significant variability in thermal maturity and mobilit...Lacustrine rift basins in China are characterized by pronounced structural segmentation,strong sedimentary heterogeneity,extensive fault-fracture development,and significant variability in thermal maturity and mobility of shale oil.This study reviews the current status of exploration and development of shale oil in such basins and examines theoretical frameworks such as“binary enrichment”and source-reservoir configuration,with a focus on five key subjects:(1)sedimentation-diagenesis coupling mechanisms of fine-grained shale reservoir formation;(2)dynamic diagenetic evolution and hydrocarbon occurrence mechanisms of organic-rich shale;(3)dominant controls and evaluation methods for shale oil enrichment;(4)fracturing mechanisms of organic-rich shale and simulation of artificial fracture networks;and(5)flow mechanisms and effective development strategies for shale oil.Integrated analysis suggests that two major scientific challenges must be addressed:the coupled evolution of fine-grained sedimentation,differential diagenesis,and hydrocarbon generation under tectonic influence and its control on shale oil occurrence and enrichment;and multi-scale,multiphase flow mechanisms and three-dimensional development strategies for lacustrine shale oil in complex fault blocks.In response to current exploration and development bottlenecks,future research will be conducted primarily to:(1)deeply understand organic-inorganic interactions and reservoir formation mechanisms in organic-rich shales,and clarify the influence of high-frequency sequence evolution and diagenetic fluids on reservoir space;(2)elucidate the dynamic processes of hydrocarbon generation,expulsion,and retention across different lithofacies,and quantify their relationship with thermal maturity,including the conditions for the formation of self-sealing systems;(3)develop a geologically adaptive,data-and intelligence-driven shale oil classification and grading evaluation system of shale oil;(4)reveal artificial fracture propagation pattern and optimize physical field coupled fracturing technologies for complex lithofacies assemblages;and(5)overcome challenges in multi-scale geological modeling and multiphase flow characterization,and establish advanced numerical simulation methodologies.展开更多
基金Project supported by the Scientific Research and Technology Development Project PetroChina Company Limited“Research on microscopic characteristics and enrichment mechanism of shallow shale gas reservoirs in Zhaotong”(No.2021DJ1903)“Field test of downhole fiber intelligent monitoring technology”(No.2020F-44).
文摘The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling in Chongqing.And after more than ten years of deep and careful cultivation,a series of important achievements have been obtained in the exploration and development.From the perspective of exploration and development history,theory and technology,this paper systematically summarizes the exploration discovery process and productivity construction progress of shale gas in the demonstration area,expounds the geological exploration theories and key technologies of mountain shale gas,and predicts their development prospect and direction.And the following research results are obtained.First,the exploration and development in the demonstration area has gone through five development stages,and so far,three major productivity construction zones have been formed,including Huangjinba and Zijinba middleedeep shale gas zones and Taiyang shallow shale gas zone,with cumulative proved geological reserves more than 3100×10^(8) m^(3) and cumulative gas production more than 72×10^(8) m^(3).It has been constructed into the third largest green shale gas demonstration base in China.Second,the“multi-field coordination and multi-element coupling”mountain shale gas enrichment,accumulation and occurrence theory of“sedimentary background controlling source rock and reservoir,reworking intensity controlling preservation,and three-dimensional sealing controlling enrichment”is put forward innovatively,and the“three-dimensional sealing system”accumulation model of extrabasinal shallow shale gas is established.Third,a series of zone selection and evaluation technologies for mountain shale gas in strongly reworked complex structural areas have been developed,and the concept of geologyeengineering integration has first been adopted to create transparent shale gas reservoirs and cultivate high-yield wells.A major exploration breakthrough has been achieved from marginal basin medium deep shale gas layers to extrabasin ultra shallow to medium shallow ones,and domestic first large-scale monoblock shallow shale gas field with reserves over 2570×10^(8) m^(3) has been discovered.Fourth,a landmark technological achievement and efficient development model with geologyeengineering integration and shale geomechanical evaluation as the core has been formed,which leads the clean,green and efficient exploration and development of mountain shale gas.In conclusion,it is necessary to implement the exploration strategic idea of“two outgoing”in the demonstration area,i.e.,“walking out of the stable area of the basin and marching into the complex structure areas in the Dianqianbei Depression”and“walking out of the WufengeLongmaxi Formation and exploring other layers for breakthrough”.What's more,it is recommended to carry out the double-layer stereoscopic horizontal well pattern deployment of“Leping Formation CBM(coal measure gas)þLongmaxi Formation shale gas”appropriately in a large scale,so as to establish a new integrated development model for the three-dimensional efficient development of mountain shale gas and CBM.
基金supported by the National Natural Science Foundation of China(U23B20155 and 42303004)China Postdoctoral Science Foundation(2023M730038)+1 种基金the Science and Technology Research Project for the China National Petroleum Corporation(2021DJ1802 and 2021YJCQ03)the National Postdoctoral Researcher Program of China(GZC20233111).
文摘The lower Cambrian Qiongzhusi(Є1 q)shale in the Sichuan Basin,formerly considered a source rock,recently achieved high gas production(7.388×105 m^(3)·d^(-1))from well Z201 in the Deyang-Anyue rift trough(DART),marking an exploration breakthrough of the world’s oldest industrial shale gas reser-voir.However,the shale gas enrichment mechanism within the DART is not fully understood.This study reviews the formation of the Qiongzhusi shale gas reservoirs within the DART by comparing them with cotemporaneous deposits outside the DART,and several findings are presented.The gas production interval was correlated with the main phase of the Cambrian explosion(lower Cambrian stage 3).In the early Cambrian ecosystem,dominant animals likely accelerated the settling rates of organic matter(OM)in the upper 1st member ofЄ_(1) q(Є_(1) q_(12))by feeding on small planktonic organisms and producing larger organic fragments and fecal pellets.High primary productivity and euxinic con-ditions contributed to OM enrichment in the lower 1st member ofЄ1 q(Є_(1) q_(11)).Additionally,shale reservoirs inside the DART demonstrated better properties than those outside in terms of thickness,brittle minerals,gas content,and porosity.In particular,the abundant OM pores inside the DART facil-itated shale gas enrichment,whereas the higher thermal maturity of the shales outside the DART pos-sibly led to the graphitization and collapse of some OM pores.Meanwhile,the overpressure of high-production wells inside the DART generally reflects better shale gas preservation,benefiting from the shale’s self-sealing nature,"upper capping and lower plugging"configuration,and limited faults and microfractures.Considering these insights,we introduced a"ternary enrichment"model for the Qiongzhusi shale gas.Although the current high gas production of Z201 was found at the reservoir 3,two additional reservoirs were identified with significant potential,thus suggesting a"multilayer stereoscopic development"strategy in future shale gas exploration within the DART.
基金Supported by the National Natural Science Foundation of China(U24B6002)National Science and Technology Major Project(2024ZD14001)Project of the Sinopec Science and Technology Department(P25196,P24207).
文摘Lacustrine rift basins in China are characterized by pronounced structural segmentation,strong sedimentary heterogeneity,extensive fault-fracture development,and significant variability in thermal maturity and mobility of shale oil.This study reviews the current status of exploration and development of shale oil in such basins and examines theoretical frameworks such as“binary enrichment”and source-reservoir configuration,with a focus on five key subjects:(1)sedimentation-diagenesis coupling mechanisms of fine-grained shale reservoir formation;(2)dynamic diagenetic evolution and hydrocarbon occurrence mechanisms of organic-rich shale;(3)dominant controls and evaluation methods for shale oil enrichment;(4)fracturing mechanisms of organic-rich shale and simulation of artificial fracture networks;and(5)flow mechanisms and effective development strategies for shale oil.Integrated analysis suggests that two major scientific challenges must be addressed:the coupled evolution of fine-grained sedimentation,differential diagenesis,and hydrocarbon generation under tectonic influence and its control on shale oil occurrence and enrichment;and multi-scale,multiphase flow mechanisms and three-dimensional development strategies for lacustrine shale oil in complex fault blocks.In response to current exploration and development bottlenecks,future research will be conducted primarily to:(1)deeply understand organic-inorganic interactions and reservoir formation mechanisms in organic-rich shales,and clarify the influence of high-frequency sequence evolution and diagenetic fluids on reservoir space;(2)elucidate the dynamic processes of hydrocarbon generation,expulsion,and retention across different lithofacies,and quantify their relationship with thermal maturity,including the conditions for the formation of self-sealing systems;(3)develop a geologically adaptive,data-and intelligence-driven shale oil classification and grading evaluation system of shale oil;(4)reveal artificial fracture propagation pattern and optimize physical field coupled fracturing technologies for complex lithofacies assemblages;and(5)overcome challenges in multi-scale geological modeling and multiphase flow characterization,and establish advanced numerical simulation methodologies.
