川中高石梯—磨溪地区中二叠统茅口组岩溶发育特征与岩溶古地貌恢复  

Development characteristics and paleogeomorphology restoration of karsts in Middle Permian Maokou Formation,Gaoshiti-Moxi area,central Sichuan Basin

作　　者：徐平生 唐松[2,4] 孙超国 梁家驹 李天军[3] 师晴 XU Pingsheng;TANG Song;SUN Chaoguo;LIANG Jiaju;LI Tianjun;SHI Qing(State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Central Sichuan Oil and Gas District,PetroChina Southwest Oil&Gasfield Company,Suining,Sichuan 629000,China;Exploration and Development Research Institute,PetroChina South-west Oil and Gasfield Company,Chengdu,Sichuan 610041,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]油气藏地质及开发工程国家重点实验室·成都理工大学,四川省成都市610059 [2]中国石油西南油气田公司川中油气矿 [3]中国石油西南油气田分公司勘探开发研究院 [4]中国石油大学(北京)地球科学学院

出　　处：《天然气勘探与开发》2023年第4期35-46,共12页Natural Gas Exploration and Development

摘　　要：四川盆地中二叠统茅口组作为四川盆地天然气重要的产层之一,其风化壳岩溶储层的贡献至关重要。通过对岩心、测井、钻录井、地震等资料分析,明确了川中高石梯—磨溪地区茅口组风化壳岩溶发育特征。在此基础上选定茅二段底面为恢复基准面,采用残厚法恢复高石梯—磨溪地区茅口组岩溶古地貌,并依据现代岩溶理论、区内微地貌形态及组合特征,对高石梯—磨溪地区茅口组岩溶古地貌单元进行划分,分析各类岩溶古地貌特征与岩溶储层关系,研究结果表明:①高石梯—磨溪地区茅口组顶部普遍存在缺失情况,并与上覆地层呈不整合接触关系,发育各种溶蚀现象,在钻录井、测井与地震上响应特征明显;②高石梯—磨溪地区岩溶古地貌可划分为岩溶缓坡和岩溶洼地两种二级岩溶地貌单元,以及峰丛洼地、峰丘洼地、丘丛垄脊沟谷等9种三级岩溶地貌单元;③高石梯—磨溪地区不同地貌类型岩溶发育条件差异大,其中岩溶缓坡具有发育规模岩溶储层的条件,尤其在岩溶负地形周围,溶蚀及保存条件优越,优质岩溶储层更为发育,是下一步的重点勘探区域。The Middle Permian Maokou Formation is one of the important gas production layers in the Sichuan Basin.Its weathered crust karst reservoirs are crucial to the production.Based on the analysis of core,logging,drilling and seismic data,the development of weathered crust karsts was characterized.Then,with the bottom surface of the second member of the Maokou Formation as the da-tum,the karst paleogeomorphology of the Formation was restored by using the residual thickness method.The karst paleogeomorpho-logical units were classified according to the modern karst theory,and the microgeomorphology and its associations in the study area.Finally,the relationships between various karst paleogeomorphical features and karst reservoirs were analyzed.The research results are as follows:(i)The top of the Maokou Formation is absent universally,and in unconformable contact with overlying strata.Various dissolution phenomena are observed,reflecting remarkable response characteristics from drilling,logging and seismic data.(ii)The karst paleogeomorphology can be divided into two second-order units:karst gentle slope and karst depression,and nine third-order units such as peak cluster depression,peak mound depression,and mound-cluster ridge ravine,etc.(iii)The karst units are very differ-ent in reservoir development conditions.Typically,the karst gentle slope has the conditions for developing large-scale karst reservoirs,especially around the negative karst topography,the dissolution and preservation conditions are excellent and high-quality karst reser-voirs are more developed.Thus,it will be the key area for subsequent exploration.

关 键 词：高石梯—磨溪地区 中二叠世 茅口组 古地貌恢复 残余厚度法 岩溶储层 

分 类 号：P618.13[天文地球—矿床学]