注水井投球暂堵酸化调剖工艺技术

Water Injection Profile Modification by Temperary Unidirectional Perforation Close with Rigid Plastic Balls and Successive Acidization

介绍了先投球暂堵再酸化的调整注水井吸水剖面技术的原理、工艺、在一口井上实施调剖的结果及此技术的优点。施工井为胡12 50注水井。吸水层3个,共厚9.0m,其中2个层相对吸水量分别占69.5%和28.1%。先用低浓度(8/1.5)土酸液3m3清洗炮眼附近区域,再投入硬质塑料球155个将高渗强吸水层的炮眼暂时封堵。接着注入含磷酸、盐酸、氢氟酸、氨基磺酸、柠檬酸、冰醋酸的无机有机复合酸液6m3酸化全井段,返排后洗井14d,恢复注水。酸化调剖后注水启动压力上升6.2MPa,吸水曲线斜率变缓,吸水层数增至7个,厚度增至15.6m,原最强吸水层相对吸水量降至10.6%,启动新吸水层4个,注水压力由23MPa降至17MPa。对应3口采油井产油量上升,含水下降(由90.0%降至84.8%),产水量减少。此法调剖作业可在1d内完成,费用很低。图1表1参4。

The principles, technologic process, field results and advantages of water injection profile modification by temperary unidirectional close of perforations with rigid plastic balls and successive acidization are presented. In water injection well Hu1250 there were 3 waterintake sublayers 9.0 m thick and 2 of them absorbed 69.5% and 28.1% of water intake. The near perforation zones of the well were washed by 3 m3 of low concentrated (8.0%/1.5%) mud acid, the perforations in high water intake zones were temperarily unidirectionally closed by rigid plastic balls input, the number of which was 155 totally, and the productive interval of the well was acidized by 6 m3 of a combinational inorganic/organic acidizing fluid on phosphoric, hydrochloric, hydrofluoric, aminosulfonic, citric, and glacial acetic acids. After backflow of the fluid and well washing in 14 days, the water injection started anew. The profile modification operation created following results: raise of startup injection pressure by 6.2 MPa; reduction in injectivity curve slope; increase of thickness of water absorbing sublayers up to 15.6 m; 4 additional sublayers being mobilized; lowering percentage water intake of the highest waterintake sublayer from 69.5% to 10.6%; and decrease in water injection pressure from 23 to 17 MPa. Increase in oil production, decrease in water production and reduction in water cut (from 90.0% to 84.8%) were observed in the 3 connected production wells. The main profiling job by this technology can be finished within 1 working day with very low cost.