Practices and future research directions of geophysical exploration for normal-pressure shale gas in complex structural areas,southeastern Chongqing
HE Xi-Peng1(), LIU Ming2, XUE Ye2, LI Yan-Jing2, HE Gui-Song2, MENG Qing-Li2, ZHANG Yong2, LIU Hao-Juan2, LAN Jia-Da2, YANG Fan2
1. East China Oil & Gas Company,SINOPEC,Nanjing 210019,China 2. Research Institute of Exploration and Development,East China Oil & Gas Company,SINOPEC,Nanjing 210019,China
Southern China boasts great potential for normal-pressure shale gas resources,with distribution areas primarily including the peripheral complex structural areas and the extrabasinal fold belts of the Sichuan Basin.These areas exhibit intricate surface and subsurface geological conditions,leading to poor seismic acquisition quality,low imaging accuracy,and unclear varying patterns of sweet spot parameters.This study systematically summarized the research achievements and technical advances in the seismic acquisition,image processing,and reservoir prediction for normal-pressure shale gas in southeastern Chongqing,including:①The development of variable-density 3D observation system design technique and the seismic excitation and reception technique for complex mountains with limestone surfaces,ensuring sufficient sampling of the reflected wave field in complex subsurface structures and improving data quality and construction efficiency;②The optimization of prestack seismic preprocessing technique for complex mountains,imaging techniques for complex structures in basin-margin transition zones, and imaging techniques for synclinal structures in extrabasinal fold belts,achieving resulting profiles with high signal-to-noise ratios,wide effective frequency bands,and high structural imaging accuracy;③The quantitative prediction of the thickness,formation pressure coefficient,and brittleness of high-quality shales based on research on petrophysical characteristics;the quantitative prediction of the organic carbon content,gas content,and porosity of shales based on statistical petrophysics;the quantitative prediction of fractures formed due to the superimposed effect of multi-stage structural modifications based on the paleo-stress field evolution revealed using the finite element simulation technique;and the ascertainment of the distribution patterns of the current in-situ stress field using the current stress field prediction technique developed using the combined spring model.The above breakthroughs have effectively guided the sweet spot prediction,exploration,and production of normal-pressure shale gas,providing a basis for the discovery of the Nanchuan normal-pressure shale gas field.Subsequent research should focus on more scientific and reasonable seismic acquisition techniques based on seismic reception using 5G wireless nodes,high-precision automatic image processing technologies for high-steep structures in complex mountains,and integrated geology-engineering-economy seismic evaluation methods for sweet spots.
何希鹏, 刘明, 薛野, 李彦婧, 何贵松, 孟庆利, 张勇, 刘昊娟, 蓝加达, 杨帆. 渝东南复杂构造区常压页岩气地球物理勘探实践及攻关方向[J]. 物探与化探, 2024, 48(2): 314-326.
HE Xi-Peng, LIU Ming, XUE Ye, LI Yan-Jing, HE Gui-Song, MENG Qing-Li, ZHANG Yong, LIU Hao-Juan, LAN Jia-Da, YANG Fan. Practices and future research directions of geophysical exploration for normal-pressure shale gas in complex structural areas,southeastern Chongqing. Geophysical and Geochemical Exploration, 2024, 48(2): 314-326.
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