苏里格气田上古生界主要含气层系黏土矿物特征及敏感性分析

苏里格气田上古生界主要含气层盒8段及山1段储层中黏土矿物广泛分布,黏土矿物含量变化影响着储层孔隙结构,易引发储层敏感性,改变储层的渗流能力,影响着研究区天然气的产能。对研究区黏土矿物特征分析及其储层敏感性分析认为,影响储层渗透性的敏感性强弱依次为水敏、酸敏、应力敏感、速敏、盐敏,其中损害较大的是水敏,其次是酸敏,并提出了相应的储层保护及改造措施。针对伊利石及伊/蒙混层含量高、易水敏的地区,进行储层压裂改造施工时需要提高砂比,少进压裂液。针对绿泥石富集区要注意酸敏对储层的伤害,但是对于改善型酸敏储层,可以采用合理的前置酸加砂压裂工艺进行改造,改善渗透率,提高单井产量。

Characteristics of Clay Minerals and Reservoir Sensitivity in Upper Paleozoic of Sulige Gas Field

It is the clay minerals that distribute widely in the key gas-bearing reservoirs of the 8th Member of Shihezi Formation and the 1st Member of Shanxi Formation in the Upper Paleozoic of Sulige gas field. The content change of clay minerals influences the pore structure features, initiates the reservoir sensitivity, changes the reservoir seepage ability and affects the gas productivity in Sulige gas field. Through studying the characteristic of clay minerals and reservoir sensitivity, it can be concluded that core permeability is influenced by water-sensitivity, acid-sensitivity, stress-sensitivity, speed-sensitivity, and salt-sensitivity by turn from the strong to the weak. It is the water-sensitivity and acid-sensitivity that are the most harmful to reservoir. At the same time, corresponding measures for reservoir protection and reconstruction are proposed. For example, it needs high sand ratio and low fracturing fluid during the course of fracture technology for water-sensitive area. Attention should be paid to acid-sensitive injury to reservoir of chlorite enrichment region. For improved acid-sensitive reservoir, rational pre-positioned acid fracturing technique could be adopted to carry out reconstruction, enhance permeability and increase single well productivity.