辽河冷家—雷家地区深层油气成藏条件研究

Deep oil and gas accumulation conditions in Lengjia-Leijia area of Liaohe Basin

冷家—雷家地区沙三段以下的深层勘探程度非常低。文章在精细地震构造解释和沉积学研究的基础上,利用该区与邻区的现有资料,对深层油气藏的形成条件进行了分析和研究。结果表明,冷家—雷家地区北东向的主干断层控制了区域构造与沉积格局,影响了油气的运移和聚集;深部层系的石油地质条件十分优越。在陈家洼陷发育有沙四段和沙三段2套优质烃源岩,有机质生烃强度大于500×104t/km2,为周边地区提供了丰富的油源;沙三下亚段、沙四段、中生界和太古宇都具有良好的储集岩;沙三中亚段发育良好的区域盖层;深层的圈闭成因多样,油气运聚条件有利,勘探潜力巨大。但该区油气藏形成的影响因素比较复杂,油气藏多为复合型,应该以潜山、岩性油气藏作为下一步的主要勘探目标。

The degree of exploration in deep zones belowthe third member of Shahejie Formation in Lengjia-Leijia area is low.Based on the fine seismic structural interpretation and sedimentology study,the available data from the study area and adjacent areas are used to analyze the formation conditions of the deep reservoirs.The result shows that the NE main fault controls the regional structure and depositional patterns in Lengjia-Leijia area,which affects the oil and gas migration and accumulation,and the oil geological condition in the deep strata is favorable.There developed two sets of high quality source rocks in the third and fourth members of Shahejie Formation in Chenjia sub-depression,with an organic hydrocarbon generation intensity greater than 500×104 t/km2,which provides abundant oil sources for the surrounding areas.Favorable reservoir rocks exist in the forth member and lower third member of Shahejie Formation,Mesozoic and Archean,and good regional seals developed well in the middle section of the third member of Shahejie Formation.There are various traps,favorable oil and gas migration and accumulation conditions and great exploration potential.However,the factors affecting the reservoir formation are complex and there exist compound reservoirs.It is suggested that the next promisingexploration targets should be primarilycentered on the hill and lithologic reservoirs.