一种新型低伤害合成聚合物冻胶压裂液体系

A Novel Low Damage Synthetic Polymer Gelled Hydrofracturing Fluid

报道了题示压裂液体系的性能.合成聚合物稠化剂FA-200不含水不溶物,水溶液呈中性,被能造成酸性环境(pH值4～6)的交联剂AC-12交联而形成冻胶.依次增加稠化剂用量(0.25%～0.6%)和交联剂用量(0.5%～0.8%),加入1.0%乳化剂和1.0%助排剂,得到了适用温度为50℃、80℃、100℃、120℃、140℃的5个配方,在相应温度下剪切50～90 min保留粘度大于150、88、98、94、53 mPa·s,在变剪切之后粘度能恢复.该体系破胶剂为过硫酸铵,其加量随温度升高而减少,破胶彻底,破胶液粘度低.0.5%稠化剂压裂液破胶后残渣含量为125.6 mg/L.该体系压裂液特别适用于碱敏性地层和CO2泡沫压裂.图5表2参2.

The performance properties of the titled fluid are presented.The synthelic polymer, FA-200, as thickener dissolves in water to form neutral solution without insoluble remainder and reacts and gelates with crosslinker AC-12 in solution in acidic media of pH=4~6 created by AC-12.By the way of increasing amount of thickener (0.25%—0.60%) and of crosslinker (0.5%—0.8%) and introducing 1.0% emulgator and 1.0% back flow aid, 5 formulated hydrofracturing fluids (HFFs) for use at 50℃, 80℃, 100℃,120℃, and 140℃are prepared, their viscosity is kept higher than 150,88,98,94, and 53 mPa.s when sheared over 50—90 minutes at 170 s-1and at corresponding test temperatures and can be recovered after sharp variation in shear proceduce.The gel breaker used is ammonium persulfate and its dosage is higher when the test temperature is higher; the gelled HFFs break down completely and the viscosity of brocken fluid is low enough.A 0.25% FA-200 HFF gives 125.6 mg residua per liter after breakdown.This HFF system is especially suitable to fracturing alkaline sensible reservoirs and to CO2foam fracturing operations.