陆相断陷油气勘探有利目标区三元定量评价方法及应用——以沧东凹陷古近系孔二段为例

Three factors evaluation and its application to the favorable oil-gas exploration targets in continental rift:taking the Ek_2 of Cangdong sag for example

陆相断陷盆地岩性油气藏形成和分布受多种因素制约,砂体、储集物性以及烃源岩是三大关键因素,因此有效地开展基于砂体、储集物性以及烃源岩的综合评价对寻找有利目标区具有重要的指导意义。作者在充分分析沧东凹陷石油地质特征基础上,针对各沉积朵体分别建立了沉积评价指数、储集物性评价指数、烃源岩评价指数,以及三元综合评价指数,对孔古近系孔店组第二段发育的11个朵体开展了定量评价。结果表明,沧县三角洲—远岸水下扇体系、舍女寺三角洲、孔店三角洲—远岸水下扇体系以及叶三拨三角洲为最有利的大型勘探区域。

The formation and distribution of lithologic reservoirs in a continental rift are controlled by many factors. Sand bodies, reservoir physical properties and source rocks are the most important key factors for hydrocarbon accumulation, so a comprehensive evaluation of the three factors has important guiding significance for finding the favorable oil-gas exploration targets. On the basis of fully analysing the petroleum geological characteristics in the Cangdong sag, sand body evolution index （I^b）, reservoir property evaluation index （Irp）, source rock evaluation index （I,r） and three factors evaluation index （I,） of every lobe are established to compose a complete evaluation system. According to the method, 11 lobes developed in Member 2 of Paleogene Kongdian Formation （Ek2） are done evaluated quantitatively. The result shows that the Cangxian system of delta-offshore subaqueous fans, Shenvsi delta, the Kongdian system of delta-offshore subaqueous fans and the Yesanbo delta are the most favorable oil-gas exploration targets.