前梨园洼陷深盆气藏

DEEP BASIN GAS ACCUMULATION IN QIANLIYUAN DEPRESSION

前梨园洼陷受凹陷边界兰聊断裂控制 ,持续发育 ,为深盆气形成提供了必要的基础。洼陷内下第三系发育良好的烃源岩 ,演化程度高 ,气源充足 ,沙河街组三段三、四亚段发育低孔低渗的致密砂岩储层 ,为深盆气藏形成创造了条件。前梨园洼陷周缘已发现气藏具有“气水倒置”、异常高压、含气井段长且产量低、气藏不受构造控制等特征。东濮凹陷是陆相断陷盆地中“断洼型”深盆气的典型代表 ,环洼的斜坡带是下一步勘探的有利区。

Being controlled by Lanliao fault on the margin, Qianliyuan depression continues developing to provide the necessary foundation of the formation of deep basin gas accumulations. Well-developed hydrocarbon source rocks occur in Lower Tertiary in the depression, which has high evolution degree and abundant gas source .Tight sand reservoirs with low-porosity and low-permeability develop in the 3rd and 4th sub-members of the third members , Shahejie Formation,which are favorable for the formation of deep basin gas accumulations.Gas accumulations, characterized by “inverted gas and water”, anomalous high-pressure, long gas-bearing interval and low production ,as well as unrelated with structure,etc.,have been discovered around Qianliyuan depression. Dongpu depression is a typical “fault-sag” type deep basin gas among the non-marine fault-depression basins, and the slope zone surrounding the depression will be favorable target for exploration in the future.