The Sinian dolomite reservoir in Dengying Formation was developed extensively in the Sichuan Basin,and typically was the facies-controlled dolomite karstic reservoir.The development of this kind of the reservoir was r...The Sinian dolomite reservoir in Dengying Formation was developed extensively in the Sichuan Basin,and typically was the facies-controlled dolomite karstic reservoir.The development of this kind of the reservoir was related with the special deposits,diagenetic environment as well as the multi-phase and multi-type dissolution and fracturing actions.The arid-hot/dry paleo-climate was favourable to develop the large-scale microbial reef-shoal bodies and moundeshoal bodies,which was characterized by the organic framework and the sea floor hardening,thus forming primary matrix pore-type reservoir.In the background of the arid-hot/dry paleo-climate,the water-rock interaction was weak,the mineral stabilization process was slowly,and the vadose pisoliths,aragonite and high-magnesium calcite were well preserved,therefore,this diagenetic environment especially was beneficial for pore preservation.Moreover,the syngenetic and penecontemporaneous dissolution,especially three phases of weathered crust karstification due to three episodes of the Tongwan movement,led to further dissolution of spaces and form numerous non-fabric selective dissolution fractures and dissolution caves along faults and fractures.Multi-phase fractures,especially the late Yanshanian-Himalayan tectonic fractures,resulted in connection among pores,vugs and dissolution caves,and improved quality of the reservoir tremendously.展开更多
The Gaoshiti-Moxi Gas Field has been discovered recently in the central part of Sichuan Basin,which might be the biggest gas field in China.In this gas field,a large amount of gas is from Neoproterozoic Sinian(Ediacar...The Gaoshiti-Moxi Gas Field has been discovered recently in the central part of Sichuan Basin,which might be the biggest gas field in China.In this gas field,a large amount of gas is from Neoproterozoic Sinian(Ediacaran)karstic carbonate rocks.The gas was originated from cracking of oil,and the oil source rocks are the Sinian and Cambrian strata.In this study,the characteristics of these carbonate reservoir rocks have been studied based on subsurface data and outcrop observation.The carbonate rocks are at the Sinian Dengying Formation,and the reservoir properties are controlled by sedimentary facies and diagenesis.The Dengying Formation is composed of algal mounds and grainstone build-ups,which were developed in a restricted platform setting from glacial period to interglacial period.Due to tectonic movement and eustatic cycle in Sichuan Basin during Neoproterozoic Era,five sedimentary cycles of transgression and regression have been developed in the Dengying Formation.According to the sedimentary facies and carbon-oxygen isotope variation,five sedimentary cycles have been recognized.Due to the penecontemporaneous dolomitization,together with hypergene karstification and late burial dissolution,the reservoir properties of the carbonates rocks have been improved greatly.展开更多
基金This work was funded by National Science and Technology Major Project of China(No.2011ZX05004).
文摘The Sinian dolomite reservoir in Dengying Formation was developed extensively in the Sichuan Basin,and typically was the facies-controlled dolomite karstic reservoir.The development of this kind of the reservoir was related with the special deposits,diagenetic environment as well as the multi-phase and multi-type dissolution and fracturing actions.The arid-hot/dry paleo-climate was favourable to develop the large-scale microbial reef-shoal bodies and moundeshoal bodies,which was characterized by the organic framework and the sea floor hardening,thus forming primary matrix pore-type reservoir.In the background of the arid-hot/dry paleo-climate,the water-rock interaction was weak,the mineral stabilization process was slowly,and the vadose pisoliths,aragonite and high-magnesium calcite were well preserved,therefore,this diagenetic environment especially was beneficial for pore preservation.Moreover,the syngenetic and penecontemporaneous dissolution,especially three phases of weathered crust karstification due to three episodes of the Tongwan movement,led to further dissolution of spaces and form numerous non-fabric selective dissolution fractures and dissolution caves along faults and fractures.Multi-phase fractures,especially the late Yanshanian-Himalayan tectonic fractures,resulted in connection among pores,vugs and dissolution caves,and improved quality of the reservoir tremendously.
基金This research was supported by the Major National Science and Technology Programs in the"Thirteenth Five-Year"Plan period(No.2017ZX05001)。
文摘The Gaoshiti-Moxi Gas Field has been discovered recently in the central part of Sichuan Basin,which might be the biggest gas field in China.In this gas field,a large amount of gas is from Neoproterozoic Sinian(Ediacaran)karstic carbonate rocks.The gas was originated from cracking of oil,and the oil source rocks are the Sinian and Cambrian strata.In this study,the characteristics of these carbonate reservoir rocks have been studied based on subsurface data and outcrop observation.The carbonate rocks are at the Sinian Dengying Formation,and the reservoir properties are controlled by sedimentary facies and diagenesis.The Dengying Formation is composed of algal mounds and grainstone build-ups,which were developed in a restricted platform setting from glacial period to interglacial period.Due to tectonic movement and eustatic cycle in Sichuan Basin during Neoproterozoic Era,five sedimentary cycles of transgression and regression have been developed in the Dengying Formation.According to the sedimentary facies and carbon-oxygen isotope variation,five sedimentary cycles have been recognized.Due to the penecontemporaneous dolomitization,together with hypergene karstification and late burial dissolution,the reservoir properties of the carbonates rocks have been improved greatly.
