滨里海盆地S区块勘探实践与认识

滨里海盆地是世界上油气最丰富的盆地之一,以下二叠统上部孔谷阶厚层盐岩为界可以将整个剖面分为盐上层系和盐下层系。S区块是以盐上层系为主要勘探目的层系的区块。自2004年收购以来,S区块先后经历了评价探索、总结提高、勘探突破和滚动扩大4个勘探阶段;从初期针对盐间、盐顶构造圈闭为主的勘探发展到以寻找可动用储量为目的的"盐檐"圈闭、岩性圈闭兼顾盐顶低幅度构造圈闭的勘探;地质储量由收购时的800×104t增长到现今9050×104t。分析认为S区块勘探成功主要基于以下几方面:老资料的剖析是新区块勘探突破的基础;"盐檐圈闭"创新性的提出是勘探成功的关键;"找线索、定盐窗;找通道、定部位;找埋深、定层系;找圈闭、定井位"四找、四定勘探评价方法是新区块快速高效勘探的基石。

Exploration of Block S in Pre-Caspian Basin

Pre-Caspian Basin is one of the richest oil and gas basins in the world. Based on the thick salt formation of Lower Permian Kungurian, the entire section is divided into upper-salt strata and lower-salt strata. Block S is the main exploration target in the upper-salt strata. This block has experienced four exploration stages - evaluation, summarization, breakthrough and progressive and enlarged exploration - since it was acquired in 2004. The exploration effort was focused on inter-salt and salt canopy structural traps in the initial stage. Then the effort aimed at searching of producing reserves, such as ＂salt eaves＂ trap, lithologic trap and salt canopy low-amplitude structural trap. The geological reserve is increased to 9050--10^4t at the present time from 800×10^4t at the purchase time. The analysis indicates that the success in exploration of Block S is based on the following aspects： analysis of old data served as the basis for making breakthrough in exploration of a new block and the proposed new conception of ＂salt eaves＂ holding the key to exploration success. The evaluation method for finding clues to locate salt window, searching channels to locate the position, finding the buried depth to determine strata series and searching traps to determine positions of well is the cornerstone for high-efficiency exploration.