Petroleum Accumulation Associated with Volcanic Activity in the Tarim Basin——Taking Tazhong-47 Oilfield as an Example

塔中47油田的发现证实在塔里木盆地围绕火成岩寻找油气田是现实的。火山活动以及由此形成的火成岩体对油气聚集的有利条件主要体现在两个方面:一是沿火成岩与围岩的接触面构成油气运移的通道,火成岩与围岩接触,似一直立的不整合面,与孔渗性好的岩层组合不仅能使油气运移而且遇有圈闭油气还会聚集成藏;二是构成火山岩遮挡的圈闭,或是对原有圈闭进行改造、分割。另外,火成岩也是一类潜在的储集层,在国内外都有不少实例,塔中隆起中-1井在二叠系火成岩中也见到油气显示。与火山活动相关的油气聚集将成为塔里木盆地一个新的勘探领域。

Petroleum Accumulation Associated with Volcanic Activity in the Tarim Basin Taking Tazhong-47 Oilfield as an Example

The discovery of the Tazhong-47 oilfield confirmed that it is realistic to explore oil and gas fields around igneous rocks in the Tarim basin. The favorable conditions for petroleum accumulation due to volcanic activity and igneous rocks formed during the activity show in two aspects. A) The contact surface of igneous rocks and the surrounding sedimentary rocks, like a vertical unconformity surface, formed the conduit of petroleum migration. Petroleum would accumulate once it encountered a trap in which the reservoir had fine porosity and permeability. B) It formed a trap barriered by igneous rocks, or changed or cut the original trap. In addition, volcanic rocks are a kind of potential reservoir, there are many such examples in the world, and oil also shows in the Permian igneous rocks in well Zhong-1 on Tazhong uplift. Petroleum accumulation associated with volcanic activity will be a new exploring field in the Tarim basin.