四川盆地蓬莱气区震旦系灯影组二段岩溶古地貌与控储模式

Karst paleogeomorphology and reservoir control model of the 2 member of Dengying Formation in Penglai gas area， Sichuan Basin， China

张自力 乔艳萍 豆霜 李堃宇 钟原 武鲁亚 张宝收 戴鑫 金鑫 王斌 宋金民

Zhili ZHANG Yanping QIAO Shuang DOU Kunyu LI Yuan ZHONG Luya WU Baoshou ZHANG Xin Dai Xin JIN Bin WANG Jinmin SONG

基于钻井岩心描述、薄片鉴定、测井资料以及三维地震资料，对四川盆地蓬莱气区震旦系灯影组二段（灯二段）表生岩溶古地貌与储层发育规律进行系统研究。结果表明：①蓬莱气区灯二段垂向上可划分为地表岩溶带、垂直渗流带、叠合带、水平潜流带和深部缓流带，其中水平潜流带发育储层厚度最大。②采用双界面法恢复了蓬莱气区灯二段岩溶古地貌，划分为4个一级古地貌单元：岩溶高地、岩溶斜坡、岩溶洼地和岩溶盆地，整体表现为“一高、一斜、两洼”的古地貌特征。③东部高石梯—磨溪地区为岩溶高地，中部发育岩溶斜坡，西北侧及西南侧为岩溶洼地。岩溶高地主要发育垂直渗流带，岩溶斜坡主要发育水平潜流带。蓬莱气区灯二段储层的发育由岩溶古地貌与沉积相联合控制。④表生岩溶储层是四川盆地蓬莱气区灯二段的主要储层类型，岩溶斜坡叠合丘滩体微相形成了优质储层。

An integration of core and thin section observation， log and 3D seismic data is applied to systematically analyze the epigenetic karst paleogeomorphology and reservoir development pattern of the 2 member of the Dengying Formation （hereafter referred to as Deng 2 Member） in the Penglai gas area， Sichuan Basin， China. Key findings are summarized as follows. First， the Deng 2 Member in the Penglai gas area can be vertically divided into the epigenetic karst zone， vertical vadose zone， superimposed zone， horizontal phreatic zone， and deep tranquil flow zone. Notably， the horizontal phreatic zone exhibits the thickest reservoirs； second， the karst paleogeomorphology of the Deng 2 Member was restored using the dual interface method. The results indicate that it can be categorized into four types of first-order paleogeomorphic units， namely karst highland， karst slope， karst depression， and karst basin， exhibiting one karst highland， one karst slope， and two karst depressions overall； third， the karst highland is situated in the Gaoshiti-Moxi area in the east， the karst slope is present in the central part of the study area， and the karst depressions are found on the northwest and southwest sides of the study area. The karst highland and karst slope primarily contain vertical vadose zones and horizontal phreatic zones， respectively. It is proposed that reservoirs in the Deng 2 Member of the Penglai gas area are jointly influenced by karst paleogeomorphology and sedimentary facies； fourth， epigenetic karst reservoirs emerge as the predominant reservoir type in the study area， with high-quality reservoirs occurring in the karst slope with superimposed microfacies of mound-shoal complexes.

10.11743/ogg20240114