W1-4油田角尾组海相碎屑岩储层钙质夹层成因机制

GENETIC MECHANISM OF THE CALCAREOUS INTERBEDS IN MARINE CLASTIC RESERVOIRS IN JIAOWEI FORMATION OF W1-40ILFIELD

根据钻井取心、薄片鉴定、测井资料等，对W1-4油田角尾组二段碎屑岩储层钙质夹层的特征、物质来源及形成机制进行了分析。研究表明：钙质夹层岩性致密，物性差，测井曲线上特征明显；其形成所需要的物质来源主要有层内溶解作用、黏土矿物转化、碎屑矿物水化作用及有机质热解4种方式；研究区钙质夹层主要集中在泥质层附近，形成机制归结为砂岩储集体与泥岩界面处碳酸盐的迁移与化学反应的耦合过程，即在泥岩中溶解，在砂岩中沉淀。

According to the data of the drilled and sampled cores, thin-section analyses, well logs and so on, the characteristics, source of minerals and genetic mechanism of the calcareous interbeds are analyzed in Member 2 clastic reservoirs in Jiaowei Formation of W1-40ilfield. The results show that the lithol0gy of the interbeds is dense, their physical properties are poor and there are obvious features on well logs ; the mineral source needed for their genesis mainly results from the following four actions： intraformational dissolution, clay mineral transformation, clastic mineral hydration and th$ pyrolysis of organic matter; the calcareous interbeds are mainly distributed near the argillaceous beds in the study area, its genetic mechanism is duo to the coupling process between the transference and chemical reaction of sandstone reservoirs and the carbonate nearby the interface of mudstone i. e. the carbonate is firstly dissolved in mudstone, and then precipitated in sandstone.