可快速交联低碳烃无水压裂液用胶凝剂的制备及性能评价

Preparation and characterization of a rapid-gelling agent for light hydrocarbons-based gelled fracture fluid

低碳烃压裂液用胶凝剂的合成方法脱胎于油基压裂液胶凝剂,两者分子结构的不同导致了其性能上的巨大差异。为了能够更精准地设计出适合低碳烃的胶凝剂,将胶凝剂中的烷基链分为两类,即提供物理交联点的高碳数烷基链和提高相容性能的低、中碳数烷基链。通过设计正交实验的方式合成多种胶凝剂样品,并通过对组分的极差分析、酸度值分析与交联时间分析相结合的方式筛选适合C5-C8低碳烃的胶凝剂。通过交联动力学实验测定了不同胶凝剂使用浓度下的交联情况,得出了胶凝剂的最佳使用浓度。使用流变仪测定最优条件下合成的胶凝剂样品的耐温耐剪切曲线。结果表明,胶液具有良好的耐剪切性能,在60℃条件下剪切2 h的过程中未出现明显的分子结构破坏,且尾粘为140 m Pa·s,可满足现场施工的需求。加入少量多元醇可制备含多元醇的胶凝剂样品。在其它条件相同的前提下,含有多元醇的胶凝剂样品具有更高的交联速率和成胶粘度,即为可快速交联的低碳烃无水压裂液用胶凝剂。

The gelling agent of light hydrocarbon-based gelled fracture fluid is different from oil-base fracturing fluid as a result of the different components. Generally,light hydrocarbons-based gelled fracture fluid and oil-base fracturing fluid are used with light oil and heavy oil as the solvent,respectively. The alkyl chains in the gelling agent are divided into two kinds,the high carbon number alkyl chains and the low carbon number alkyl chains. High carbon number alkyl chains interacted with each other and created physical crosslinks. The existence of low carbon number alkyl chains helped to raise the compatibility between the gelling agent and the solvents. A L18（ 37） orthogonal test was carried out and a series of gelling agent samples were synthesized. Range analysis were carried out through the contents of these samples,and we filtered them according to the acid and the gelling time. Gelling kinetics were tested to get the appropriate use concentrations. The thermal stability test showed that,this fracture fluid has a viscosity of140 mP a·s after sheared with a isothermal shear rate of 170 s-1at 60 ℃. A new gelling agent sample was synthesized as a small amount of polyol was added. This new gelling agent has shorter gelling time and higher viscosity than traditional gelling agents in the same experimental conditions. Which is the polyol-including gelling agent is a fast-crosslinking gelling agent.