吴A区侏罗系油藏黏弹自调剂调驱效果分析

Analysis of the effect of viscoelastic self regulating agent in the Jurassic reservoir of Wu A district

吴A区延9、延10底水油藏于2017年开始水驱动用程度大幅度下降,只有38.0%,受重力影响,吸水段逐渐下移,受地层平面非均质性和层间非均质性强、前期注入强度和采液强度大的影响,底水过早锥进导致油井见水,甚至见注入水发生水淹,常规堵水调剖措施无法完成地层深部地带封堵。为延缓注入水沿大孔道和微裂缝等地层深部高渗通道突进,提高注入水的波及体积,改善吸水剖面,吴A区延9、延10油藏于2022年8月开展黏弹自调剂调驱矿场试验。试验结果表明,2022年8月-2023年10月注入黏弹自调剂后,调驱效果较好,深入地层后能有效滞留于孔喉,平均单井日注水量下降,注入压力由7.20MPa上升到7.80MPa;整体吸水指数由38.1m^(3)/(d·MPa)下降到25.1m^(3)/(d·MPa);黏弹自调剂在地层中形成有效封堵,有效改善油水流度比以及提高洗油效率,注入黏弹自调剂后月度递减率由0.10%下降到-0.40%,月度含水率上升幅度由0.03%下降到0.02%。

The bottom water reservoir of Yan 9 and Yan 10 in Wu A area has experienced a significant decrease in water drive utilization since 2017,with only 38.0%.Due to the influence of gravity,the water absorption section gradually moves downwards.Due to the strong heterogeneity of the formation and interlayer,as well as the strong injection and production intensity in the early stage,the bottom water cone prematurely leads to water breakthrough in the oil well,and even causes water whelming.Conventional water plugging and profile control measures cannot complete the sealing of deep areas of the formation.In order to delay the injection of water along deep high permeability channels such as large pores and micro cracks,increase the swept volume of injected water,and improve the water absorption profile,the Yan 9 and Yan 10 oil reservoirs in Wu A area conducted a field test of viscoelastic self regulating agent in August 2022.The test results showed that after vis-coelastic self regulating agent was injected from August 2022 to October 2023,the effect of profile control and displacement was good,and it could effectively stay in the pore throat.The average daily water injection volume of a single well decreased,and the injection pres-sure increased from 7.20 MPa to 7.80 MPa.The overall water absorption index decreased from 38.1 m^(3)/(d-MPa)to 25.1 m^(3)/(d·MPa).Viscoelastic self regulating agents formed effec-tive sealing in the formation,effectively improving the oil-water flow ratio and enhancing oil washing efficiency.After injecting viscoelastic self regulating agent,the monthly decline rate decreased from 0.10%to-0.40%,and the monthly increase in water content decreased from 0.03%to 0.02%.