苏北盆地张家垛油田阜三段油气富集规律

Hydrocarbon enrichment patterns of the 3^(rd) member of Funing Formation in Zhangjiaduo oilfield,Subei Basin

苏北盆地张家垛油田阜宁组三段具有良好的油气勘探潜力,是今后中国石化华东分公司增储上产的一个重要领域。但由于该储层非均质性强,油气富集规律不清楚,严重制约了下一步的勘探开发。通过对烃源岩、储层、圈闭等成藏基本地质条件的研究,利用泥岩压实规律进行异常压力分析。研究结果表明:①阜宁组异常高压为欠压实成因,与干酪根生烃无关,深层优质储层与欠压实密切相关,异常压力高值区是优质储层分布区;②异常压力高值分布在阜三顶-阜四段,高异常压力形成区域性封闭层,油气主要富集于高异常压力之下的低势区;③高异常压力最有利于阜三段油气成藏,而低异常压力区有可能在阜三段的上覆地层戴南组成藏。最终利用高压封闭的区域性盖层和沉积微相研究,认为阜三段向南成藏条件会变好,是下一步勘探的目标区。

The 3rd member of Funing Formation has a great potential for oil and gas exploration and will be one of the most important targets for reserve growth and production addition of SINOPEC Huadong Oilfield Company.However,the reservoir heterogeneity is strong and hydrocarbon enrichment patterns are poorly understood,seriously constraining future exploration and development.Based on study of the basic geologic conditions for source rocks,reservoirs,and traps,abnormal pressure is analyzed according to the rules of mudstones compaction.The abnormal pressures of Funing Formation are caused by ofundercompaction,instead of hydrocarbon generation of kerogen.The deep high-quality reservoirs are closely related with undercompaction and the high-quality reservoirs occur in areas where the abnormal pressure is high.The high abnormal pressure occurs in interval from the top 3rd member to 4th member of Funning Formation and forms a regional seal.Hydrocarbons mainly accumulate in low potential areas below this seal.High abnormal pressure favors hydrocarbon accumulation in the 3rd member of Funning Formation,while low abnormal pressure may be favorable for hydrocarbon accumulation in the overlying Dainan Formation.Based on study of the regional high abnormal pressure seal and sedimentary microfa-cies,it is believed that the hydrocarbon accumulation conditions of the 3rd member of Funning Formation are better to the south,thus the 3rd member to the south is a favorable target for future exploration.