中国西北三大含油气盆地石炭系生烃潜力对比

摘要

The hydrocarbon generation potential of Carboniferous in Zhunggar Basin,Tarim Basin and Qaidam Basin is compared based on Lithofacies paleogeography,source rock hydrocarbon generating potential and hydrocarbon accumulation characteristics,and it is held that the Carboniferous of three basins are all the sedimentary strata of marine facies and paralic facies,the source rocks are mature to highly mature,they have a certain hydrocarbon-generating potential,but the source rock quality of Qaidam Basin is worse than that of Zhunggar Basin and Tarim Basin. Tarim Basin is similar to Qaidam Basin in hydrocarbon source rock type,hydrocarbon generation evo-lution and hydrocarbon accumulation law. The hydrocarbon source rock includes limestone,mudstone and carbonaceous mudstone,they all have experienced secondary hydrocarbon generation,so the hydrocarbon of Tarim Basin and Qaidam Basin is mixed source hydrocar-bon. By means of the successful experience in the oil and gas exploration of the Carboniferous of Zhunggar Basin and Tarim Basin,the whole exploration of the Paleozoic strata including Cambrian-Ordovician,Carboniferous in Qaidam Basin needs to be strengthened. The intrusive rocks have an important impact on the maturity of hydrocarbon source rock. Ancient reservoirs,secondary hydrocarbon reser-voirs and mixed source hydrocarbon reservoirs are the main preservation forms of the hydrocarbon from the Carboniferous source rocks.%从岩相古地理、烃源岩生烃潜力及油气成藏特征等角度，对准噶尔、塔里木和柴达木盆地石炭系生烃潜力进行了对比，认为三大盆地石炭系均为海相、海陆交互相沉积地层，烃源岩整体处于成熟—高成熟阶段，具有一定的生烃潜力，柴达木盆地石炭系烃源岩质量比准噶尔及塔里木盆地差。塔里木和柴达木盆地在烃源岩类型、生烃演化及油气成藏规律上有一定的相似性，烃源岩类型包括灰岩、泥岩、碳质泥岩，且均经历了二次生烃，具有混源油气等特征。借鉴准噶尔、塔里木2个盆地石炭系油气勘探的成功经验，柴达木盆地需加强寒武-奥陶、石炭系等古生界地层的整体勘探，岩体侵入对于烃源岩成熟度产生重要影响，古油藏、次生油气藏及混源油气藏共同构成以石炭系为油源的油气保存形式。