GX-3井绒囊流体暂堵重复酸化技术

GX-3井2002年酸化投产,至2014年产量正常递减至5×104 m3/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,p H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 m Pa·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 m3,静置7 h后排残液。恢复生产后,产气量由5×104 m3/d提高到7×104 m3/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一种有效的新方法。

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

In 2002, Well GX-3 was acidized and put into production, and its production decreased normally to 5×104 m3/d in 2014, so it is proposed to re-acidize the well in order to increase production. For the purpose of improving the effectiveness of re-acidization, the fuzzy-ball temporary plugging fluid was used to plug the originally acidized wormhole of high conductivity, hence forcing the acid solution to enter the non-acidized formations. Indoor tests show that, after plugged by fuzzy-ball fluid, the bearing capacity of previously acidized wormhole of high conductivity was improved by 78.06 MPa, the changes of plastic viscosity and yield point of temporary plugging fluid with pH 2 to 7 was below 3%, and the recovery of the permeability of originally acidized wormhole of high conductivity was 88.64%. 120 m3 of fuzzy-ball temporary plugging fluid was prepared on site to plug the originally acidized wormhole of high conductivity. The density of such fluid was 0.90~0.95 g/cm3, its plastic viscosity was 15~30 mPa·s and its yield point was 15~35 Pa. Wellhead was tested with a pressure of 3 MPa, 6.5 m3 of hydrochloric acid was injected, then the residual fluid was produced after standing for 7 h. When production was resumed, the gas yield was increased from 5×104 m3/d to 7×104 m3/d, indicating that acidization occurred after the fuzzy-ball fluid plugged the high-conductivity wormhole previously acidized, which did not damage the gas productivity of original fractures and instead added new gas producing layers, hence providing a new and effective method for re-acidification of carbonate reservoirs.