GX-3井绒囊流体暂堵重复酸化技术

Technology of re-acidizing Well GX-3 by temporary plugging with fuzzy-ball fluid

GX-3 井2002 年酸化投产,至2014 年产量正常递减至5×10^4 m^3/d,拟再次酸化增产.为提高重复酸化效果,使用绒囊暂堵流体封堵原酸化高传导蚓孔,迫使酸液进入未酸化地层.室内测试绒囊流体暂堵后提高原酸化高传导蚓孔承压能力78.06 MPa,pH 值2-7 的暂堵流体塑性黏度、动切力等变化3% 以下,原酸化高传导蚓孔渗透率恢复值88.64%.现场配制密度0.90-0.95 g/cm3、塑性黏度15-30 mPa·s、动切力15-35 Pa 的绒囊暂堵流体120 m3 封堵原酸化高传导蚓孔,井口清水试压3MPa 后注入盐酸6.5 m^3,静置7 h 后排残液.恢复生产后,产气量由5×10^4 m^3/d 提高到7×10^4 m^3/d,表明绒囊暂堵流体封堵原酸化高传导蚓孔后再酸化,不损伤原缝产气能力,并新增产量贡献层,为碳酸盐岩储层重复酸化转向提供了-种有效的新方法.

In 2002, Well GX-3 was acidized and put into production, and its production decreased normally to 5×10^4 m^3/d in2014, so it is proposed to re-acidize the well in order to increase production. For the purpose of improving the effectiveness of reacidization,the fuzzy-ball temporary plugging fluid was used to plug the originally acidized wormhole of high conductivity, henceforcing the acid solution to enter the non-acidized formations. Indoor tests show that, after plugged by fuzzy-ball fluid, the bearingcapacity of previously acidized wormhole of high conductivity was improved by 78.06 MPa, the changes of plastic viscosity and yieldpoint of temporary plugging fluid with pH 2 to 7 was below 3%, and the recovery of the permeability of originally acidized wormholeof high conductivity was 88.64%. 120 m3 of fuzzy-ball temporary plugging fluid was prepared on site to plug the originally acidizedwormhole of high conductivity. The density of such fluid was 0.90-0.95 g/cm^3, its plastic viscosity was 15-30 mPa·s and its yield pointwas 15-35 Pa. Wellhead was tested with a pressure of 3 MPa, 6.5 m^3 of hydrochloric acid was injected, then the residual fluid wasproduced after standing for 7 h. When production was resumed, the gas yield was increased from 5×10^4 m^3/d to 7×10^4 m^3/d, indicatingthat acidization occurred after the fuzzy-ball fluid plugged the high-conductivity wormhole previously acidized, which did not damagethe gas productivity of original fractures and instead added new gas producing layers, hence providing a new and effective method forre-acidification of carbonate reservoirs.