黏弹剂调剖在姬塬油田侏罗系油藏中的应用

Application of viscoelastic agent profile control in Jurassic reservoir of Jiyuan oilfield

姬塬油田侏罗系油藏位于鄂尔多斯盆地中西部,属于低渗透砂岩油藏,油藏油水运移以孔隙型渗流为主。进入开发中后期,油井水淹现象严重。姬塬油田先后应用“交联聚合物冻胶+体膨颗粒”、“PEG单相凝胶调驱剂”、“纳米级微球”等调剖体系对侏罗系油藏注水井开展调剖,虽然在降低油藏递减、控制含水率上升幅度等方面取得了一定效果,但对于水淹井降含水率方面效果不明显。近年来,姬塬油田通过开展侏罗系油藏油井水淹机理研究,优化调剖体系,筛选了一种新型黏弹剂进行调剖,室内评价及现场实施均证明该黏弹剂性能可靠。2021—2022年,通过在姬塬油田56个侏罗系油藏水淹井组采用黏弹剂调剖后,井组月度递减率由2.59%下降至1.01%,月度含水率上升幅度由0.61%下降至0.08%。同时,大部分水淹井含水率下降明显,平均有效期内单井组增油达226 t。按照油价45美元/桶计算,投入产出比1.00∶2.11,实施效益较好。

The Jurassic reservoir of Jiyuan oilfield is located in the central western part of the Ordos Basin and belongs to a low-permeability sandstone oil reservoir.The oil and water movement in the reservoir is dominated by pore type seepage.After entering the middle and late stages of development,the phenomenon of water flooding in oil wells is serious.Jiyuan oilfield has successively applied profile control systems such as"cross-linked polymer gel+bulky particles","PEG single-phase gel profile control and displacement agent"and"nano microsphere"to profile control water injection wells in Jurassic reservoirs.Although some results have been achieved in reducing reservoir decline and controlling water cut rise,the effect on water cut reduction in water flooded wells is not obvious.In recent years,Jiyuan oilfield has conducted research on the mechanism of water flooding in Jurassic oil wells,optimized the profile control system,and selected a new viscoelastic agent for profile control.Both indoor evaluation and on-site implementation have proven that the performance of the viscoelastic agent is reliable.From 2021 to 2022,after using viscoelastic agents to profile control 56 flooded well groups in Jurassic reservoir of Jiyuan oilfield,the monthly decline rate of the well group decreased from 2.59%to 1.01%,and the monthly water cut increase decreased from 0.61%to 0.08%.At the same time,the water content of most water flooded wells has significantly decreased,and the average effective period of single well group oil increase has reached 226 t.Based on the oil price of$45/barrel,the input-output ratio is 1.00∶2.11,and the implementation benefits are good.