论文部分内容阅读
柴达木盆地生物气勘探一直以第四系中深层为勘探目标,然而近年来的勘探表明,柴达木盆地晚第四纪超浅层蕴藏着丰富的生物气资源,资源量达到1000×108m3。根据超浅层生物气产状特征,通过对各成藏要素分析,指出充足的气源条件、有利的储集条件、有效的封盖条件和圈闭条件是研究区超浅层低产生物气藏形成的充要条件,其中气源主要来自第四系中深部的暗色泥岩,所形成生物气通过“渗漏窗”运移至浅层;储层主要为粉砂岩和泥质粉砂岩;盖层则主要由盐层、石膏层和软泥层组成,纵向上形成多元互补的有利封盖条件;圈闭则主要为岩性和背斜型。依据产气深度分布特征,超浅层生物气藏可分为盐壳遮挡气藏、小型背斜气藏和岩性气藏,而生物气则以游离气和水溶气的形式赋存在各类气藏中。
In the Qaidam Basin, the exploration of biogas has long been targeted at the middle and deep Quaternary. However, exploration in recent years shows that there are rich biogas resources in the ultra-shallow Palaeozoic of the Qaidam Basin with a resource of 1000 × 108m3 . According to the characteristics of ultra-shallow biogenic gas, through the analysis of each reservoir forming element, it is pointed out that sufficient gas source conditions, favorable reservoir conditions, effective capping conditions and trap conditions are ultra-shallow and low-yield gas reservoirs in the study area The formation of the necessary and sufficient conditions, in which the gas source is mainly from the dark Quaternary mudstone, the formation of biogas through the “leakage window” to the shallow migration; the main reservoir is siltstone and muddy siltstone; The cap layer is mainly composed of salt layer, gypsum layer and soft mud layer, forming multiple complementary favorable sealing conditions longitudinally; the trap is mainly lithology and anticline. According to the distribution characteristics of gas production depth, ultra-shallow bio-gas reservoirs can be divided into salt-sheltered gas reservoirs, small anticline gas reservoirs and lithologic gas reservoirs, while biogas is present in the form of free gas and water-soluble gas Hidden.