三工河组油藏原始含油饱和度研究及形成机理

Original Oil Saturation Study and Forming Mechanism of J_1s Pool

吐哈盆地台北凹陷火焰山逆掩构造带火焰山断裂上下盘中下体罗统发现多个油藏,产层普遍为油水同出,油藏多为低幅度、低含油饱和度油藏,其中下休罗统三工河组油藏最为典型。火焰山构造三工河组油藏含油饱和度低的主要原因是圈闭幅度小,油气聚集驱动压力小;储层物性差,细毛细管孔隙体积大,孔隙结构复杂,油驱替地层水的程度低,地层条件下可动油水共存;微孔隙发育,泥质呈分散状,束缚水含量高。探讨油水同产的低含油饱和度油藏形成机理对这类油气藏的勘探开发具有重要的指导意义。

Several oil pools have been discovered in middle Jurassic and lower Jurassic stratum in coping wall and lying wall of Huoyanshan fault which lies in Huoyanshan overthmst tectonic zone, Taibei sag of Tuha basin. The reservoirs yield oil with water simultaneously. The reservoirs have low structural closure, with low saturation. Among them ,J1s reservoir is representative. There are three primary aspects resulting in low saturation. The first one is about the low structural closure which results in small driving force for hydrocarbon to congregate. The second one, which induce the bad oil - displacing - water degree and movable oil existing with movable water together in original reservoir condition, is about bad petrophysical character , large volume of fine capillary pore and complex hole configuration. The third one is the high content of bound water caused by abundant tiny pore and clay distriburing dispersedly. It will be significance for prospecting and exploitation of such kind of reservoirs to probe into the forming mechanism of low saturation reservoirs which yieht oil with water simultaneously.