无聚合物水力压裂液

Polymer - Free Fluid for Hydraulic Fracturing

党民芳¹,高桂玲¹,李臣生²

Dang Minfang, Gao Guiling, Li Chensheng

1. 中原石油勘探局井下特种作业处,2.中原油田分公司采油工程事业部

Downhole Special Service Division , Zhongyuan Petroleum Exploration Bureau , Henan 457061 , P. R. China

实施水力压裂措施后,遗留在裂缝中的聚合物残渣降低了压裂效果,本文讲述了一种新型、易配制的无聚合物压裂液,该压裂液由衍生于长链脂肪酸的季铵盐组成。在盐水中,该压裂液可形成高度缠结的螺旋状胶束,从而变稠。此类胶束整体结构与聚合物链相似。由于这种压裂液的粘度取决于胶束的性质,因此,可通过改变其胶束结构进行破胶。该压裂液接触到碳氢化合物、或用地层水稀释后就发生破胶。因此,不需要使用常规的破胶剂,采出的油或气就可作为该压裂液体系的破胶剂。本文研究了这种无聚合物表面活性剂压裂液的结构特点与其化学物理特性间的关系,并介绍了该压裂液的结构、流变性、滤失性、传导性及其增产数据。

Polymer residues that stay in the fracture after a hydraulic f racturing treatment can limit treatment effectiveness. A new and easy - to - prepare , polymer free fluid that consists of a quaternary ammonium salt derived from a long - chain fatty acid is described. In brine , it builds viscosity due to the formation of highly entangled worm - like micelles. The micelles have a gross structure similar to a Polymer chain. Since the viscosity of the fluid depends on the nature of micelles, the fluid can be broken by changing this micellar structure. The breaking occurs when the fluid is exposed to hydrocarbons or diluted with formation waters. Therefore , conventional breakers are not required , and the produced oil or gas can act as breakers for this fluid system. The structural characteristics of the Polymer f ree suffectant fluid to its chemical and physical properties are correlated in this paper. Structure , rheology ,fluid loss and conductivity of this surfactant fluid together with its production data are presented.