粘弹性清洁压裂液的作用机理和现场应用

常规水基压裂液破胶后具有较高的残渣量,对支撑裂缝伤害较大,在一定程度上影响了油气田的产量.研究开发出了新型的VES清洁压裂液体系,它是由VES粘弹性表面活性剂和水或盐水组成.该压裂液集粘弹性、抗剪切性、自动破胶性于一体.通过分析VES清洁压裂液的粘弹性形成机理、抗剪切机理、携砂机理、破胶机理、滤失机理、伤害机理,表明粘弹性清洁压裂液具有独特的分子结构和独特的流变性能,它具有配制简便,使用添加剂种类少,不存在残渣,对储层伤害小等特点.现场实验表明,清洁压裂液具有破胶性能,施工摩阻低,携砂能力强,可有效地控制缝高.与使用水基压裂液的邻井相比,粘弹性清洁压裂液压裂施工后增产效果明显.

The mechanism of viscoelastic clean fracturing fluid and its application in oilfield

The conventional hydraulic fracturing fluid leaves high content of residue after gel breaking, produces severe damage to the induced fractures, affecting oil/gas production in some degree. A novel clean fracturing fluid system VES was developed, which was composed of viscoelastic surfactant VES and water/salt water. The fracturing fluid performs characteristics such as viscoelasticity, anti-shearing and automatically breaking. Analyses on mechanism of viscoelasticity forming, anti-shearing, proppant carrying, gel breaking, filtration controlling and damage to the rock revealed that the fluid has particular molecule structure and unique rheology property. It is easy to prepare with less addition of additives and without residue left. Field using verified that the fluid possesses good gel breaking property, the operating friction value is low, the proppant carrying ability is strong and fracture length is in control. The stimulation result of the viscoelastic fracturing fluid is move evident better than those using the conventional hydraulic fracturing fluid.