【摘要】 乌尔逊凹陷大磨拐河组的成岩作用受沉积物源的性质、砂体微相和地温梯度的影响。北部地区的沉积物来源于切割的岩浆弧,抗压实能力强,次生孔隙恰好发育在液态烃的生成之前或同时;南部地区来源于未切割的岩浆弧,抗压实能力弱,次生孔隙发育早,与大量液态烃的生成时间相隔甚大。大磨拐河组储集层的主要成岩矿物有蒙脱石、伊利石、伊/蒙混层,高岭石、片钠铝石、碳酸盐、石英、钠长石和黄铁矿等。以与地温有关的成岩变化为依据,分别将南北两地区大磨拐河组自上而下分为四个成岩带,即浅带、中带、深带和超深带。中成岩带的主要储层类型为水下扇、层状浊积岩、三角洲和砂坝等。由沉积物源和砂体微相所控制的成岩强度的区域性交化,导致了储层特征的差异。沉积物源、砂体微相和成岩作用的对比分析,对寻找本区有利的含油气储层具有重要的指导意义。更多还原

【Abstract】 Diagenesis of Damoguaihe formation, Wurxun depression is influenced by sedimentary provenance, sandbody microfacies, and geothermal gradient. Reservoir sandstones in the northern depression, derived from dissected magmatic arcs, display a relatively gentle compaction with the depth of burial. Secondary porosity developed just before hydrocarbon migration. Reservoir sandstones in the southern depression, derived from undissected magmatic arcs, show relatively high compaction with depth of burial. Early diagenetic processes increased porosity in the shallow volcaniclastics. As too much time was available between the secondary dissolution zone and the zone of intense hydrocarbon generation, mechanical compaction occluded the porosity. Authigenic minerals in the reservoirs of Damoguaihe formation are montmorillonite (smectite), illite, illite-smectite, kaolinite, dawsonite, carbonate, quartz, albite, and pyrite. Based on diagenetic events, related to temperature, Damoguaihe formation can be divided into four diagenetic zones: shallow, intermediate, deep, and ultradeep. The major reservoirs in intermediate diagenetic zone are subaqueous fans, deltas, and bars. Reservoir quality trends in intermediate diagenetic zone are products of regional variations in intensity of diegenesis, controlled by sedimentary provenance and sandbody microfacies. Correlations of sedimentary provenance, sandbody microfacies, and diagenesis are of great importance to the exploration in this area.更多还原