东濮凹陷北部地区温压系统与油气分布的关系

Relationship between Geothermal-Geopressure System and Hydrocarbon Distribution in North Part of Dongpu Depression

针对东濮凹陷北部地区地温-地压系统特征研究薄弱的问题,基于东濮凹陷北部地区地温和地压实测数据,应用地温-地压系统原理分析了东濮凹陷北部地区地温场、地压场及温-压系统特征,并结合构造格局分析了它们对油气分布的影响。研究表明,东濮凹陷北部地区地温梯度总体较高,洼陷带具有埋藏深、地温高的特点。纵向上发育常压型温压系统和高压型复式温压系统。平面上可划分为高温高压、常温高压、高温常压、常温常压和低温常压5个分区,油气主要富集于能量低的常温常压区;与渤海湾盆地其它凹陷油气富集区不同,由于东濮凹陷北部地区膏盐盖层发育,从而在能量高的常温高压区也聚集了大量油气。

In view of the weak research on the characteristics of geotemperature-pressure system in the northern part of Dongpu Depression, based on the measurements of ground temperature and pressure, the characteristics of geotemperature field, geopressure field and temperature-pressure system in the northern part of Dongpu depression are analyzed by T-P system theory. Combined with the structure distribution pattern, their effects on hydrocarbon distribution have been analyzed. The study demonstrates that the temperature gradient in north part of Dongpu depression is high, the sag zone has the characteristics of deep buried and high geotemperature, which is beneficial to the maturity of source rocks and the formation of hydrocarbon in the sag zone. The deep overpressure could be as the important motivating force for hydrocarbon migration. In vertical, the T-P system includes static pressure geothermal-geopressure system and overpressure complex geothermal-geopressure system. The lateral T-P system can be divided into 5 subareas, namely, HTHP, NTHP, HTNP, NTNP and LTNP, and the low-energy NTNP is the place where petroleum mainly accumulates. Different from other hydrocarbon rich depressions in the Bohai bay bain, due to the development of gypsum?salt cap rock, a large amount of hydrocarbon has accumulated in the high-energy NTHP.