首页|Sedimentary microfacies of Member 5 of Xujiahe Formation in the Dongfengchang area,Sichuan Basin

Sedimentary microfacies of Member 5 of Xujiahe Formation in the Dongfengchang area,Sichuan Basin

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Member 5 of the Upper Triassic Xujiahe Formation(T3X5)in central Sichuan Basin has made a break-through in exploration recently.However,this new stratum has not been investigated sufficiently with respect to basic geology,making its types and distribution of sedimentary facies unclear,which severely restricts its subsequent exploration evaluation.In this study,types of sedimentary microfacies in the first sand group of T3X5(T3X5)are clarified through core observation and logging interpretation using core,log and seismic data,and then distribution of sedimentary microfacies in T3X15 is determined according to seismic waveform features and seismic prediction.The results show that T3X5 in the Dongfengchang area is mainly composed of deltaic deposits of several microfacies,such as delta front underwater distributary channel,sheet sand,and interdistributary bay.On seismic sections,different microfacies are significantly different in waveform features,the underwater distributary channel is characterized by one trough between two peaks,while diversion bay exhibits chaotic reflections between T6 and T51.The sedi-mentary microfacies varied greatly during the depositional period of T3X15 in the Dongfengchang area,this is because that the sediment supply was mainly controlled by the southwest and southeast prov-enance regions.Three superimposed underwater distributary channels are developed in the Dong-fengchang area.The phase-1 superimposed underwater distributary channel in the northwest transition to sheet sand in the northeast,the phase-2 superimposed underwater distributary channel in the south extends shortly,the phase-3 superimposed underwater distributary channel in the northeast has a large development scale.These research findings are helpful to guide the subsequent exploration of T3X5 gas reservoir and also theoretically significant for investigating the depositional evolution of the Xujiahe Formation in central Sichuan Basin.

Seismic faciesSedimentary microfaciesXujiahe formationUpper triassicDongfengchang areaCentral Sichuan Basin

Yanqing Huang、Jian Wang、Junlong Liu、Nan Duan、Kaihua Xiao、Dawei Qiao、Yan Li、Ai Wang

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SINOPEC Petroleum Exploration & Production Research Institute,Beijing 100083,China

Sinopec Southwest Oil & Gas Company,Chengdu,610095,Sichuan,China

2024

石油研究(英文)

石油研究(英文)

ISSN:
年,卷(期):2024.9(3)