阴离子型VES压裂液在裂缝性油藏中的研究应用

裂缝性油藏中出现的天然裂缝会在水力压裂过程中发生剪切或者破坏等一系列现象,这导致了压裂液的滤失情况十分严重,进一步造成砂堵或者加砂困难等问题。针对裂缝性油藏中压裂液滤失严重的问题,通过研究阴离子型VES压裂液的性能来降低压裂液的滤失量。测试了VES压裂液的流变性能、耐温性能、粘弹性能、悬砂性能及破胶性能。研究表明,VES压裂液的耐剪切性很好,可以维持长时间的工作要求,在低剪切力下可以维持粘度的不变,在提高剪切速率时粘度会开始下降,在剪切速率得到回降后粘度又可以快速恢复;VES压裂液在60℃的地层中利用率最高,此温度下的粘度最大,弹性也最大,不可用于高于80℃的地层;VES压裂液支撑剂沉降速度很低悬砂性能很好,破胶很快且很彻底;这些优越的性能可以大量减少裂缝性油藏在水力压裂过程中压裂液的滤失量。

Research and Application of Anionic VES Fracturing Fluid in Fractured Reservoirs

Shear slip, destroying and other phenomena of natural cracks in fractured reservoirs always appear in the process of hydraulic fracturing, which can lead to serious fracturing fluid filtrate loss to cause sand plugging problem. In order to solve the problem of serious fracturing fluid filtrate loss in fractured reservoirs, the filtrate loss of the fluid was reduced by studying the performance of the anionic VES fracturing fluid. The rheological properties, temperature resistance, viscoelastic properties, suspension properties and breaking properties of VES fracturing fluid were tested. The research shows that VES fracturing fluid shear resistance is very good, and can meet long time work requirements, the viscosity can be maintained in the low shear, the viscosity will begin to decrease in improving the shear rate, but the viscosity can quickly recover after the shear rate dropping; The utilization rate of VES fracturing fluid at 60 ℃ in the stratum is the highest, the viscosity and the elasticity are the largest at the temperature, VES fracturing fluid is not suitable for the formation of more than 80 ℃; the proppant settling velocity in VES fracturing fluid is low, sand suspension performance is very good, and the gel breaking speed is fast, while the gel breaking degree is high; these superior performance can reduce the filtrate loss amount of fracturing fluid in the hydraulic fracturing process of cracked reservoirs.