Exploration of the Sinian-Lower Paleozoic formations in the Sichuan Basin starts from the 1950s,and is tortuous and complex.To summarize the exploration experiences is of great significance of reference for exploratio...Exploration of the Sinian-Lower Paleozoic formations in the Sichuan Basin starts from the 1950s,and is tortuous and complex.To summarize the exploration experiences is of great significance of reference for exploration of oil and gas in deep carbonate rocks of the Sichuan Basin.Gas accumulation in the Anyue oversize gasfield is chiefly controlled by the Deyang-Anyue intra-platform rift and central Sichuan paleouplift.The intra-platform rift controls the scale hydrocarbon generation center and effective hydrocarbon plays.The Anyue gasfield is characterized by near-source hydrocarbon accumulation.The marginal zone of intra-platform rift and high part of the paleouplift control the scale distribution of favorable facies belts of reservoir development,and overlapped by paleokarstic reformation,the reservoirs are widely distributed.The intra-platform rift and paleouplift jointly control formation of the scale traps and hydrocarbon enrichment.Gas reservoir features and major controlling factors for hydrocarbon accumulation have some differences in the main play strata,such as Longwangmiao Formation,and Member 4 and Member 2 of Dengying Formation.The gas reservoir in the Longwangmiao Formation is a lithologic gas reservoir under the tectonic setting,and the inherited paleouplift is a key for reservoir formation and hydrocarbon accumulation.The gas reservoir in the Member 4 of Dengying Formation is mainly controlled by large structural-stratigraphic composite traps,and the gas reservoir in the Member 2 of Dengying Formation is the structural trap.Distribution of the large gasfields in the Dengying Formation is controlled by the intra-platform rift,near-source hydrocarbon-reservoir configuration controlled by the ancient erosion plane and stratigraphic sealing in the updip direction.For exploration and development of the Anyue gasfield,four series of technologies are developed,namely,reservoir seismic fine description technology,well logging fine evaluation technology of gas layers,fast drilling technology of complex strata,and stimulation technology for high temperature and high pressure gas layers.Technical progresses provide powerful guarantee for efficient exploration and development of the oversize gasfields.展开更多
A breakthrough has been recently made in the hydrocarbon exploration of the Permian pyroclastic rocks in the Jianyang Area,western Sichuan Basin,China.With an aim to decipher the impacts of the eruption environment,th...A breakthrough has been recently made in the hydrocarbon exploration of the Permian pyroclastic rocks in the Jianyang Area,western Sichuan Basin,China.With an aim to decipher the impacts of the eruption environment,the temperature of hydrothermal fluids,and the paleo-salinity on the formation of authigenic mineral assemblage and pores,this study implements comprehensive petrographic and geochemical studies through the integrated core and thin section analyses.The data presented demonstrate that the Permian volcanic intervals are intensively affected by an event of Emei taphrogeny.During basaltic magma upward migration,fractional crystallization of anorthose results in slightlyalkaline magma.The specific pyroclastic rocks are formed by the eruption of slightly-alkaline magma in the sea or a salt lake and subsequent hydrothermal alteration.During deposition and diagenesis,the authigenic mineral association is constrained jointly by the sodium-rich and high salinity water environment,and mid-high temperature,high-salinity hydrothermal fluid.Specifically,the sodium-rich hydrothermal fluid,which may sustain till the late diagenesis stage,caused pervasive albitization of pyroclastic rocks,then leading to mineral transformation and formation of a series of mineral associations.Therefore,zeolitization of volcanic glass and vesicle-infillings of zeolite is an essential condition for later mineral transformation and dissolution.Albitization of analcite,recrystallization induced by deep hydrothermal fluids,and both meteoric and deep burial dissolution expanding the micro-pore space ultimately formed porous pyroclastic reservoirs.展开更多
基金The work was supported by the National Science and Technology Major Project of China(No.2016ZX05004005,2016ZX05007004).
文摘Exploration of the Sinian-Lower Paleozoic formations in the Sichuan Basin starts from the 1950s,and is tortuous and complex.To summarize the exploration experiences is of great significance of reference for exploration of oil and gas in deep carbonate rocks of the Sichuan Basin.Gas accumulation in the Anyue oversize gasfield is chiefly controlled by the Deyang-Anyue intra-platform rift and central Sichuan paleouplift.The intra-platform rift controls the scale hydrocarbon generation center and effective hydrocarbon plays.The Anyue gasfield is characterized by near-source hydrocarbon accumulation.The marginal zone of intra-platform rift and high part of the paleouplift control the scale distribution of favorable facies belts of reservoir development,and overlapped by paleokarstic reformation,the reservoirs are widely distributed.The intra-platform rift and paleouplift jointly control formation of the scale traps and hydrocarbon enrichment.Gas reservoir features and major controlling factors for hydrocarbon accumulation have some differences in the main play strata,such as Longwangmiao Formation,and Member 4 and Member 2 of Dengying Formation.The gas reservoir in the Longwangmiao Formation is a lithologic gas reservoir under the tectonic setting,and the inherited paleouplift is a key for reservoir formation and hydrocarbon accumulation.The gas reservoir in the Member 4 of Dengying Formation is mainly controlled by large structural-stratigraphic composite traps,and the gas reservoir in the Member 2 of Dengying Formation is the structural trap.Distribution of the large gasfields in the Dengying Formation is controlled by the intra-platform rift,near-source hydrocarbon-reservoir configuration controlled by the ancient erosion plane and stratigraphic sealing in the updip direction.For exploration and development of the Anyue gasfield,four series of technologies are developed,namely,reservoir seismic fine description technology,well logging fine evaluation technology of gas layers,fast drilling technology of complex strata,and stimulation technology for high temperature and high pressure gas layers.Technical progresses provide powerful guarantee for efficient exploration and development of the oversize gasfields.
基金This work was granted by the National Natural Science Foundation of China(Grant No.41202109)the National Major Science and Technology Projects of China(Grant No.2016ZX05007004001)+1 种基金the Innovation Foundation of PetroChina Carbonate Key laboratory(RIPED-HZDZY-2019-JS-695)the China Scholarship Council.Thanks are expressed to our colleagues involved in igneous rocks researching in the Sichuan Basin,as well as to several anonymous reviewers from which this article has benefited.
文摘A breakthrough has been recently made in the hydrocarbon exploration of the Permian pyroclastic rocks in the Jianyang Area,western Sichuan Basin,China.With an aim to decipher the impacts of the eruption environment,the temperature of hydrothermal fluids,and the paleo-salinity on the formation of authigenic mineral assemblage and pores,this study implements comprehensive petrographic and geochemical studies through the integrated core and thin section analyses.The data presented demonstrate that the Permian volcanic intervals are intensively affected by an event of Emei taphrogeny.During basaltic magma upward migration,fractional crystallization of anorthose results in slightlyalkaline magma.The specific pyroclastic rocks are formed by the eruption of slightly-alkaline magma in the sea or a salt lake and subsequent hydrothermal alteration.During deposition and diagenesis,the authigenic mineral association is constrained jointly by the sodium-rich and high salinity water environment,and mid-high temperature,high-salinity hydrothermal fluid.Specifically,the sodium-rich hydrothermal fluid,which may sustain till the late diagenesis stage,caused pervasive albitization of pyroclastic rocks,then leading to mineral transformation and formation of a series of mineral associations.Therefore,zeolitization of volcanic glass and vesicle-infillings of zeolite is an essential condition for later mineral transformation and dissolution.Albitization of analcite,recrystallization induced by deep hydrothermal fluids,and both meteoric and deep burial dissolution expanding the micro-pore space ultimately formed porous pyroclastic reservoirs.
