辽河盆地东部凹陷异常高压油气藏成藏模式

Formation Models for Oil and Gas Reservoirs with Abnormal High Pressure in Eastern Sag of Liaohe Basin

利用测井资料和地震资料对辽河盆地东部凹陷典型地区进行了地层古、今压力的研究,认为牛居—青龙台地区沙一段—沙三段地层存在异常高压,牛居地区超压形成于馆陶早期,后期具有封隔油气的能力;青龙台地区超压形成于东营末期,封隔能力不强;葵花岛地区沙三段、沙一段和东三段地层异常高压明显,其中沙三段和沙一段超压形成于东营末期或更早。对牛居构造断裂背斜油气藏和葵花岛构造断鼻油气藏的成藏解剖表明,牛居—青龙台地区油气藏的主要成藏期为东营末期和现今,葵花岛地区油气藏主要成藏期为东营中期、东营晚期和现今。从地层压力演化史和油气藏成藏期的关系出发,提出了高压油气藏的三种成藏模式:早期略超压模式、早期高超压模式和晚期超压模式。

Logging data and seismic data are used to study the ancient and current formation pressure in the typical areas of the eastem sag in Liaohe basin. It is concluded that there exist abnormal high pressure in Es_1～Es_3 formations in the Niuju-Qinglongtai area. The over pressure of Niuju area is formed in the early Ng, capable of sealing oil and gas in the later stage. The over pressure of Qinglongtai area is formed at the end of the Ed. It is weak in the sealing capability. The abnormal high pressure is obvious for the Es_3, Es_1 and Ed_3 formations in Kuihuadao area, with that of the Es_3 and Es_1 formations is formed at the end of the Ed or earlier. The analysis of Niuju faulted anticline oil and gas reservoir and Kuihuadao fault-nose oil and gas reservoir indicated that the main reservoir forming stage in Niuju-Qinglongtai area is at the end of the Ed and the present time while that for the oil and gas reservoirs in Kuihuadao is the middle of the Ed, the late Ed and the present time. Based on the relations between the formation pressure evolution history and the oil and gas reservoir forming stage, three kinds of models are proposed for the high-pressure oil and gas reservoirs-the over pressure model in the early stage, the high over pressure model in the early stage and the high over pressure model in the late stage.