In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields loc...In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics ＆different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy.展开更多
Mockina slovakensis,thought to have evolved from Epigondolella praeslovakensis,is an important species of the Norian(Upper Triassic),generally considered as the representative of the uppermost Alaunian to upper Sevati...Mockina slovakensis,thought to have evolved from Epigondolella praeslovakensis,is an important species of the Norian(Upper Triassic),generally considered as the representative of the uppermost Alaunian to upper Sevatian in the Tethys.The previous description of M.slovakensis was incomplete,thus has led to some misidentifications.We thus update the description of M.slovakensis and discuss its comparisons and occurrence based on the new conodont investigations in Dolomia di Forni and the data from previous literatures.The conodont assemblage in the succession of Dolomia di Forni is dominated by M.slovakensis,along with rare M.postera and E.praeslovakensis.We described two morphotypes of M.slovakensis(morphotypes A and B),on the basis of shape of the lateral profile.These two morphotypes can also be observed in the E.praeslovakensis.Moreover,M.slovakensis is usually documented as almost monospecific conodont association in intraplatform basins,thus its paleogeographic implications are also discussed.展开更多
Based on the drilling,logging,seismic and outcrop data,the formation and evolution of the late Sinian to early Cambrian intraplatform basin in Sichuan Basin was studied.Through the analysis of the total residual thick...Based on the drilling,logging,seismic and outcrop data,the formation and evolution of the late Sinian to early Cambrian intraplatform basin in Sichuan Basin was studied.Through the analysis of the total residual thickness of Member 3+Member 4 of Dengying Formation,the total thickness of Maidiping Formation+Qiongzhusi Formation,and lithofacies characteristics of Maidiping Formation,the distribution of the intraplatform basin was defined and its controlling effect on natural gas distribution of Dengying Formation was revealed.The intraplatform basin was characterized by small total residual thickness of Member 3 and Member 4 of Dengying Formation,the large total thickness of Maidiping Formation and Qiongzhusi Formation,and the deep-water phosphorous-carbonaceous-siliceous mudstone in Maidiping Formation.Horizontally,the intraplatform basin was mainly distributed in Qingchuan-Ziyang-Yibin area,and experienced four evolution periods.During the period of Member 1 and Member 2 of Dengying Formation,the Sichuan Basinwas a rimmed carbonate platform with the well developed mounds and shoals on the platform margin and its interior.The intraplatform basin in western Sichuan Basin was initially formed due to the first episode of Tongwan movement.During the period of Member 3 and Member 4 of Dengying Formation,the depositional center was formed in Moxi,Changning and Zhengxiong area due to extension and rifting of the Upper Yangtze Craton,thereafter,the Sichuan Basin evolved into a rimmed carbonate platform with an intraplatform basin.The second episode of Tongwan movement between Sinian and Cambrian led to the overall uplift and exposure of Sichuan Basin characterized by weathering denudation at high position and downward fluid erosion at low position.During the period of Maidiping Formation,three lithofacies zones were developed horizontally,and the third episode of the Tongwan movement between Maidiping Formation and Qiongzhusi Formation modified the sedimentary geomorphology locally.During the period of Qiongzhusi Formation and Canglangpu Formation,continuous deposition made the Sichuan Basin evolve into a gentle siliciclastic ramp.The evolution of the intraplatform basin not only promoted formation of high-quality platform-margin dolomite reservoirs of Member 4 of Dengying Formation,but also controlled distribution of the high-quality source rocks of Maidiping Formation and Qiongzhusi Formation.The dolomite of Dengying Formation in the surrounding area of the intraplatform basin was the most favorable hydrocarbon exploration area because of its good source-reservoir configuration.展开更多
基金supported by the National Science and Technology Major Project of China(No.2011ZX05029-003)CNPC Science Research and Technology Development Project,China(No.2013D-0904)
文摘In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics ＆different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy.
基金supported by the National Natural Science Foundation of China(Nos.41830320,45172002,41661134047)。
文摘Mockina slovakensis,thought to have evolved from Epigondolella praeslovakensis,is an important species of the Norian(Upper Triassic),generally considered as the representative of the uppermost Alaunian to upper Sevatian in the Tethys.The previous description of M.slovakensis was incomplete,thus has led to some misidentifications.We thus update the description of M.slovakensis and discuss its comparisons and occurrence based on the new conodont investigations in Dolomia di Forni and the data from previous literatures.The conodont assemblage in the succession of Dolomia di Forni is dominated by M.slovakensis,along with rare M.postera and E.praeslovakensis.We described two morphotypes of M.slovakensis(morphotypes A and B),on the basis of shape of the lateral profile.These two morphotypes can also be observed in the E.praeslovakensis.Moreover,M.slovakensis is usually documented as almost monospecific conodont association in intraplatform basins,thus its paleogeographic implications are also discussed.
基金This work was funded by National Science and Technology Major Project of China(Grant No.2011ZX05004).
文摘Based on the drilling,logging,seismic and outcrop data,the formation and evolution of the late Sinian to early Cambrian intraplatform basin in Sichuan Basin was studied.Through the analysis of the total residual thickness of Member 3+Member 4 of Dengying Formation,the total thickness of Maidiping Formation+Qiongzhusi Formation,and lithofacies characteristics of Maidiping Formation,the distribution of the intraplatform basin was defined and its controlling effect on natural gas distribution of Dengying Formation was revealed.The intraplatform basin was characterized by small total residual thickness of Member 3 and Member 4 of Dengying Formation,the large total thickness of Maidiping Formation and Qiongzhusi Formation,and the deep-water phosphorous-carbonaceous-siliceous mudstone in Maidiping Formation.Horizontally,the intraplatform basin was mainly distributed in Qingchuan-Ziyang-Yibin area,and experienced four evolution periods.During the period of Member 1 and Member 2 of Dengying Formation,the Sichuan Basinwas a rimmed carbonate platform with the well developed mounds and shoals on the platform margin and its interior.The intraplatform basin in western Sichuan Basin was initially formed due to the first episode of Tongwan movement.During the period of Member 3 and Member 4 of Dengying Formation,the depositional center was formed in Moxi,Changning and Zhengxiong area due to extension and rifting of the Upper Yangtze Craton,thereafter,the Sichuan Basin evolved into a rimmed carbonate platform with an intraplatform basin.The second episode of Tongwan movement between Sinian and Cambrian led to the overall uplift and exposure of Sichuan Basin characterized by weathering denudation at high position and downward fluid erosion at low position.During the period of Maidiping Formation,three lithofacies zones were developed horizontally,and the third episode of the Tongwan movement between Maidiping Formation and Qiongzhusi Formation modified the sedimentary geomorphology locally.During the period of Qiongzhusi Formation and Canglangpu Formation,continuous deposition made the Sichuan Basin evolve into a gentle siliciclastic ramp.The evolution of the intraplatform basin not only promoted formation of high-quality platform-margin dolomite reservoirs of Member 4 of Dengying Formation,but also controlled distribution of the high-quality source rocks of Maidiping Formation and Qiongzhusi Formation.The dolomite of Dengying Formation in the surrounding area of the intraplatform basin was the most favorable hydrocarbon exploration area because of its good source-reservoir configuration.
