川西地区雷口坡组顶部不整合面特征及其对储层的影响

近年来，川西地区在雷口坡组顶部钻遇优质储层，取得了天然气勘探的重大突破。基于野外露头、钻井岩芯、薄片、录井、测井、常量元素和（碳、氧）同位素等资料的分析，对川西地区雷口坡组顶部不整合面特征及其对储层影响进行了研究。结果表明，不同地区雷顶储层受不整合面的影响存在差异性:彭州地区雷顶发育裂缝型灰岩储层，储层发育不受不整合面影响；新场地区雷顶发育孔隙型白云岩储层，不整合面对储层有改善作用；回龙地区雷顶发育石膏溶蚀孔、洞型岩溶储层，不整合面对储层发育起控制作用。岩性和微古地貌是影响川西地区古岩溶作用发育的决定性因素。回龙地区广泛发育的规模性岩溶储层是川西雷口坡组下一步勘探的有利目标。 

Unconformity characteristics of the top of Leikoupo Formation and their effect on reservoirs in the western Sichuan basin

Recently, a great breakthrough in gas exploration has been made at the top of Leikoupo Formation, where high-quality reservoirs were found by drilling in the western Sichuan basin. Based on outcrop, core, thin section, log, element analysis, carbon and oxygen isotopes, this work defined the unconformity characteristics and analyzed their influence on the reservoirs. The results show varied effects of the unconformity at different places. The Pengzhou area hosts fractured limestone reservoirs, where the conformity has no effect on them. In the Xinchang area, paleokarst may have improved the reservoir quality. Conformity has controlled reservoir distribution in the Huilong area, because in the subaerial environment gypsum dissolution and pores are preserved. Lithofacies and micro-palaeogromorphology are main factors of karstification affecting the development of paleokarst in western Sichuan basin . Large-scale paleokarst reservoirs developed widely in the Huilong area, which would be the favorable target for next exploration.