准噶尔盆地西北缘风城组白云岩成因及油气富集因素

利用钻井、岩心、地震、测井及地球化学资料，分析准噶尔盆地西北缘二叠系风城组白云岩沉积环境、成因、分布规律及白云岩储集层油气富集高产因素。风城组白云岩按产状和沉积构造可分为纹层状泥质白云岩、薄层状白云岩和斑状白云岩，主要为准同生白云岩和后生白云石化白云岩。准同生白云岩形成于半深湖咸水环境；后生白云石化白云岩是发育在半深湖咸水环境下的碳酸盐岩灰泥在成岩期经后生白云石化作用形成。白云岩主要分布在火山喷发或逆冲断裂活动形成的古地貌斜坡上。白云岩储集层的储集空间主要为溶蚀孔隙和裂隙。白云岩储集层富集高产的控制因素是裂缝及构造背景。图8表3参20

Dolomites genesis and hydrocarbon enrichments of Fengcheng Formation in the northwestern margin of Junggar Basin

Using the data of cores, well logging interpretations, seismic sections and experimental geochemistry, this paper analyzes the sedimentary environment, genesis, and distribution of dolomites, as well as the hydrocarbon enrichment factors of dolomite reservoirs in the Permian Fengcheng Formation. According to attitude and structure, the dolomites of the Fengcheng Formation are divided into lamina dolomites, thin-bed dolomites, and spotted dolomites and they are mainly the penecontemporaneous and epigenetic dolomites. The former is deposited in a saline semi-deep lake, while the latter results from the dolomitization of lime mud that was deposited in a saline semi-deep lake during the diagenetic stage. The dolomites are distributed at the palaeoslopes formed by volcano eruption and movement of thrust faults and the main dolomite reservoir spaces are dissolved pores and fractures. The factors controlling hydrocarbon enrichment are fractures and structural background.