四川盆地自贡区块茅口组岩溶储层发育特征及其主控因素  

Development characteristics and main controlling factors of Maokou Formation karst reservoirs in Zigong Block of the Sichuan Basin

作　　者：王国锋 张大伟[1] 邓守伟[1] 杨光[1] 宋文礼 WANG Guofeng;ZHANG Dawei;DENG Shouwei;YANG Guang;SONG Wenli(PetroChina Jilin Oilfield Company,Songyuan,Jilin 138001,China)

机构地区：[1]中国石油吉林油田公司,吉林138001

出　　处：《天然气工业》2022年第9期63-75,共13页Natural Gas Industry

摘　　要：二叠系茅口组长期以来是四川盆地勘探开发的重点和难点,早期主要沿背斜核部和断裂布井,近年来在早期层控岩溶新认识下揭开了向斜勘探的序幕。为了进一步明确盆地自贡区块茅口组岩溶储层发育特征及主控因素,在茅口组岩性、测井响应特征研究的基础上,开展了储层类型划分,并根据残余厚度法和印模法恢复了茅口组顶部岩溶古地貌。研究结果表明:(1)茅口组岩溶储层类型可划分为岩溶孔隙型、岩溶缝洞型和岩溶裂缝型等3种;岩溶裂缝型储层和岩溶缝洞型储层主要沿北东走向的断裂带发育,岩溶孔隙型储层的发育与断层分布的关系较弱,主要受控于生物碎屑、砂屑滩的分布,在整个研究区均有发育。(2)识别出岩溶台地、岩溶坡地2个二级地貌单元,并可细分出8种三级地貌单元;岩溶古地貌控制了岩溶储层发育规模,高产气藏多分布于岩溶台地的溶丘、溶峰以及岩溶坡地的丘丛垄脊沟谷地貌单元中,且岩溶台地和岩溶坡地的过渡区域也是岩溶储层发育的有利区;广泛发育的高能滩为岩溶储层提供了物质基础,高能滩受溶蚀改造可形成优质的岩溶孔隙型储层。(3)断裂带的发育极大地改善了渗流条件,断裂带规模越大、断裂带之间以及断裂带与地表水系相交频率越高,从而有利于形成岩溶裂缝型或者岩溶缝洞型储层。结论认为,高能相带是储层发育的基础,岩溶与断裂是优质储层发育改造的关键,该研究成果为自贡区块乃至于整个四川盆地茅口组岩溶型气藏的深化勘探指明了方向。The Permian Maokou Formation has been the focus and difficulty of exploration and development in the Sichuan Basin for a long period. In the early stage, wells are deployed mainly along anticlinal cores and faults. In recent years, the early strata-bound karst is recognized, which unveils the prelude of synclinal exploration. In order to further clarify the development characteristics and main controlling factors of Maokou Formation karst reservoirs in Zigong Block of the Sichuan Basin, this paper carries out reservoir classification after investigating the lithology and logging response characteristics of the Maokou Formation. In addition, karst paleogeomorphology at the top of the Maokou Formation is restored using residual thickness method and impression method. And the following research results are obtained. First, the Maokou Formation karst reservoirs can be classified into three types, i.e., karst porous reservoirs, karst fractured-vuggy reservoirs, and karst fractured reservoirs. Karst fractured reservoirs and karst fractured-vuggy reservoirs are mainly developed along the NE trending fault zone, while karst porous reservoirs are developed in the whole study area and their development is less related to the distribution of faults, but mainly controlled by the distribution of bioclasts and sandy beaches. Second,two second-level geomorphological units are identified, i.e., karst platforms and karst slopes, which are further divided into eight thirdlevel geomorphological units. The karst paleogeomorphology controls the development scale of karst reservoirs. High-yield gas reservoirs are mostly distributed in the hills and peaks of karst platforms and the hills, ridges and valleys of karst slopes. The transitional area between karst platform and karst slope is also a favorable area for the development of karst reservoirs. The widely developed high-energy shoals provide a material base for karst reservoirs, and after being dissolved, they can form good-quality karst porous reservoirs. Third,the development of

关 键 词：四川盆地 自贡区块 茅口组 岩溶储层 古地貌 主控因素 残余厚度法 印模法 

分 类 号：P618.13[天文地球—矿床学]