鄂尔多斯盆地西峰油田压裂液对储层伤害的微观机理研究

Microcosmic Analysis of Damage of Fracturing Fluids to Reservoirs in Xifeng Oilfield of Ordos Basin

为了搞清压裂液引起低渗储层伤害的主要因素,优化压裂液体系,以最有效手段减小或消除这些伤害,采用真实砂岩模型进行了压裂液伤害机理的实验,并对照储层地质特征、流体性质和储层敏感性分析,对压裂液伤害储层的微观机理进行了分析研究。结果表明,压裂液引起的水锁伤害率为46.6%,储层压力系数低和压裂液引起残渣对储层伤害率为25.7%,对裂缝伤害率为60%。通过筛选合适的表面活性剂,改变岩石润湿性,来降低压裂液的水锁伤害;开发和研究低残渣压裂液体系,来降低压裂液残渣伤害,提高储层向裂缝渗流能力。这为开发适用于低渗油田的新型低伤害压裂液体系及相关技术提供了理论支持。

Experiments are conducted on the damage mechanism of fracturing fluids by using the real sandstone model to identify the reservoir damage factors caused by fracturing fluids,to optimize fracturing fluid system,and reduce or even eliminate the damage with the most effective method.What's more,the micro-mechanism of reservoir damage caused by fracturing fluids is analyzed on the basis of analyzing the reservoir geological characteristics,fluid properties,and reservoir sensitivity.Experimental results show that the rate of water-block damage caused by fracturing fluids is 46.6%,the rates of reservoir damage and fracture damage caused by residue due to the low reservoir pressure coefficient and fracturing fluids are 25.7% and 60% respectively.Rock wettability is altered by selecting out suitable surfactant so as to reduce the water-block damage caused by fracturing fluids.The reservoir damage caused by fracturing fluid residue is reduced by developing the fracturing fluid system with low residue so as to improve the permeable capability of seepage flow from reservoirs to fractures.All of this provides theoretical support for the development of novel low-damage fracturing fluid systems and relevant technologies suitable to low permeability oilfields.