东濮凹陷桥口构造沙三^(3-4)亚段气藏储集因素

Gas accumulation factors of S_3^(3-4) sub-interval in Qiaokou structure Dongpu Depression

目的 为更好地勘探桥口构造含气层沙三段中下部的天然气,研究了影响气藏的诸因素。方法利用薄片观察统计和X衍射分析,对桥口构造沙三3 4亚段气藏岩性特征、沉积相特征进行了研究。结果 该区含气层段具砂层厚度薄,粒度细,沉积相变快,埋藏深度大,储层物性纵、横向差异明显的储集特点;影响含气层段的储集因素包括岩石学组分、沉积相、砂体展布、成岩作用及物性等;沉积相是最主要的因素,以重力流沉积为主;好的储集体主要有湖底扇中扇辫状水道砂体和轴向重力流水道砂体。结论 通过以上研究,结合气源条件,指出该地区天然气勘探的方向应为桥东斜坡带。

Aim The physical property is poor and the gas output is instability in gas reservoir of s^(3-4)_3 sub-interval,Qiaokou structure. Methods The lithological and facies characteristics are studied based on slice′s observing and accounting,and analysis of X duiffraction.Results It is found that the sand in gas-bearing interval in this area is of thin bed,fine grain,faster change of sedimentary facies,deep buried depth,and reservoir physical property is obviously different from both the vertical and horizontal.Further research showed that reservoir factors that affect oil-bearing interval include petrological component,sedimentary facies,sand body distribution,diagenesis,and physical property,etc,among which sedimentary facies are the most important one.Gravity flow deposit is dominant in s^(3-4)_3 sub-interval in this area.Good reservoir mainly includes sublacustrine fan-in-fan braided channel sand body and axial gravity flow channel sand body.Conclusion With the above research and consideration of the gas source condition,it has indicated the main exploration tanrgets for a natural gas in this area.