一种新型无瓜胶电吸引聚合物压裂液体系

A New Non-Guar Gum Polymer Fracturing Fluid

从代替传统瓜胶压裂液的指导思想出发,利用分子间的静电吸引作用,研制出一种耐高温无残渣的新型压裂液。该压裂液稠化剂为研制出的一种中低分子量、碳链较长且具有正电荷的聚合物,其与研制出的电吸引诱导剂作用可以形成剪切可逆的空间网状结构。从耐高温性、抗剪切性以及对地层伤害性和润湿性改变等方面对该压裂液进行了评价。该压裂液在130℃、170 s-1下剪切1 h后黏度在45 mPa·s以上,残渣量为0,岩心伤害率为20.56%,可使地层岩石表面润湿性由亲油性向亲水性转变,从而有利于油气的开采;并且该压裂液在高速剪切下黏度降低,剪切速率降低时黏度又随之恢复,这一特点可很大程度地降低其摩阻。该压裂液在靖50-X井盒8段的压裂施工进行了试验应用,增产效果显著。其主剂合成步骤简单,原料易得,体系价格相对较低,可以成为瓜胶压裂液的替代产品。

A new high temperature residue-free fracturing fluid was developed to replace the traditional guar gum fracturing fluid. This new fracturing fluid, after one hour of shearing at 130 ℃ and 170 s-1, still retained a viscosity of greater than 45 mPa·s. It had no residue on cores and percent permeability impairment of cores was 20.56%, and the surface of the core turned from organophilic to hydrophilic. Comparison of conventional guar gum fracturing fluid and this new fracturing fluid showed that there is very slight difference in high temperature performance and shearing capacity between the two, while the latter is superior to the former in permeability protection and gel breaking. Wettability reversal of rock surface caused by the new fracturing fluid makes it advantageous in oil and gas production. The shear thinning effect of the new fracturing fluid greatly reduces flowing friction, making it a suitable substitute for guar gum fracturing fluid. The new fracturing fluid has been successfully used in the fracturing job of well Jing50-X, showing satisfactory results.