东濮凹陷北部低有机质丰度烃源岩高效成藏机理

Mechanism of high efficient reservoir formation of low abundance source rocks in the north of Dongpu Depression

鹿坤,李长春,周峰,张成富,徐田武

中国石化中原油田分公司勘探开发研究院，河南 濮阳 457001 中国石化中原油田分公司文卫采油厂，河南 濮阳 457001

东濮凹陷北部烃源岩总有机碳质量分数（TOC）平均为0.80%，70%样品的TOC低于1.00%，按陆相烃源岩的评价标准，属于差—中等烃源岩；而从北部找到的储量来看，该区域则属于富油凹陷。为弄清低有机质丰度烃源岩高效成藏机理，运用有限空间热压模拟、镜下鉴定等方法对不同岩相组合和不同沉积环境的烃源岩生排烃特征进行了研究。研究结果表明：东濮凹陷高温、高压、频繁砂泥岩互层的特点，决定了烃源岩排烃效率高、有机碳恢复系数大、残余TOC低；东濮凹陷北部为咸水环境，烃源岩具有原始生产力高、早生烃、早排烃、生烃周期长、生烃率高等特征；东濮凹陷多套盐岩良好的封盖能力，利于油气的聚集保存。

The average organic carbon content of source rocks in the north of Dongpu Depression is 0.80% and 70% of the samples is lower than 1.00%. According to the evaluation criteria of continental source rocks, they belong to the differential to medium source rocks. And the reserves found in the north, which belong to oil-rich sag. In order to find the mechanism of efficient reservoir formation of low abundance source rocks, the hydrocarbon generation and expulsion characteristics of source rocks in different lithofacies assemblages and sedimentary environments are studied through the simulation experiment research and microscopic identification. The results show that the characteristics of high temperature and high pressure and frequent sand mud interbed determine the hydrocarbon expulsion efficiency, organic carbon recovery coefficient, and low residual organic carbon content; the saline lake has the characteristics of high original production, hydrocarbon source rocks generated and discharged early, long period, hydrocarbon source rate is high; many sets of salt rocks in Dongpu Depression have good sealing ability, which is conducive to the accumulation and preservation of oil and gas.

10.6056/dkyqt202104007