川北地区寒武系油气成藏主控因素及富集区带

Main Controlling Factors to Form Cambrian Reservoirs and Gas Accumulation Belts, Northern Sichuan Basin

通过川北及邻区寒武系油气成藏主控因素分析,明确了寒武系油气成藏富集规律及有利区带。分析认为,寒武系主要为下生上储式成藏组合,垂向及侧向近源是富集成藏的物质基础,浅滩相带及颗粒滩叠加岩溶作用改造形成的优质储层是早期富集成藏的前提,成藏期具有古构造背景的岩性圈闭是成藏富集的保障,持续良好的保存条件是早期油气富集、晚期调整富集成藏的关键。川北元坝—仁和场地区寒武系具备良好的油气富集成藏条件及匹配关系,是下步勘探有利富集成藏区带。

After an analysis on the main controlling factors to form Cambrian reservoirs in northern Sichuan Basin and surrounding areas, we not only made reservoir-forming and accumulation rules clear, but also proposed some favorable belts. It is deemed that(1) the Cambrian is dominantly a reservoir-forming assembly of both lower source and upper reservoir; and(2) vertical and lateral near source is the material basis for oil and gas accumulation, highquality reservoirs in shallow shoal facies belt and grain shoal generated from superimposed karstification are the premise to form reser-voirs at the early stage, lithological trap with paleostructure background is the guarantee during reservoir-forming period, and better preservation conditions is the key to oil and gas accumulation at the early stage and to adjusting this accumulation at the later stage. The Cambrian in Yuanba-Renhechang area of northern Sichuan Basin will become the favorable one for next exploration due to better reservoir-forming conditions and assembly.