A new evaluation method of gel’s dynamic sealing characteristic in porous media
来源期刊：中南大学学报(英文版)2014年第8期
论文作者：WU Zhi-wei(吴志伟) YUE Xiang-an(岳湘安) LI Li-feng(李立峰) ZHANG Yi(张义) YANG Zhi-guo(杨志国)
文章页码：3225 - 3232
Key words：polyacrylamide; gel; sealing characteristic; oil recovery
Abstract: Water shutoff through injection wells is one of the most important techniques used for water injection profile control and modification in severely heterogeneous reservoirs, aiming at stabilizing oil production. It has been widely reported that the effectiveness and efficiency of water shutoff using gel is mostly dependent on the gel dynamic sealing properties in the porous media. Firstly the gelation strength and gelation time of polymer gel were evaluated. Then, core flowing experiments were conducted before and after gelation in a 32 m long sand pack. In addition, water flooding core experiments were also carried out in a long core of 80 cm before and after injecting gel system to check the reliability of this evaluation method. The experimental results show that moderate-strength gel can be formed at 65 °C. According to the integrated evaluation of the plugging coefficient, plugging strength and water breakthrough time, the gel particles are capable of migrating to a distance of 7.47 m from the injection point of the 32 m long sand pack during the water injection process after gelation. Based on sands gelation status and effluent analyses, the effective migration distance of the gel particles is 4-14 m. Through the core flooding experiments using the 80 cm heterogeneous core, it is evidenced that the gel can be formed in the deep reservoir (40.63% of total length) with the plugging strength as high as 6.33 MPa/m, which leads to extra oil recovery of 10.55% of original oil in place (OOIP) by water flooding after gel treatment.
WU Zhi-wei(吴志伟)1, 2, YUE Xiang-an(岳湘安)1, 2, LI Li-feng(李立峰)3, ZHANG Yi(张义)4, YANG Zhi-guo(杨志国)1, 2
(1. Key Laboratory of Petroleum Engineering of Ministry of Education
(China University of Petroleum), Beijing 102249, China;
2. Petroleum Engineering Faculty, China University of Petroleum, Beijing 102249, China;
3. 1st Oil Production Plant of Jiangsu Oilfield (SINOPEC), Yangzhou 225265, China;
4. Zakum Oil Development Company, Abu Dhabi 46808, United Arab Emirates)
Abstract:Water shutoff through injection wells is one of the most important techniques used for water injection profile control and modification in severely heterogeneous reservoirs, aiming at stabilizing oil production. It has been widely reported that the effectiveness and efficiency of water shutoff using gel is mostly dependent on the gel dynamic sealing properties in the porous media. Firstly the gelation strength and gelation time of polymer gel were evaluated. Then, core flowing experiments were conducted before and after gelation in a 32 m long sand pack. In addition, water flooding core experiments were also carried out in a long core of 80 cm before and after injecting gel system to check the reliability of this evaluation method. The experimental results show that moderate-strength gel can be formed at 65 °C. According to the integrated evaluation of the plugging coefficient, plugging strength and water breakthrough time, the gel particles are capable of migrating to a distance of 7.47 m from the injection point of the 32 m long sand pack during the water injection process after gelation. Based on sands gelation status and effluent analyses, the effective migration distance of the gel particles is 4-14 m. Through the core flooding experiments using the 80 cm heterogeneous core, it is evidenced that the gel can be formed in the deep reservoir (40.63% of total length) with the plugging strength as high as 6.33 MPa/m, which leads to extra oil recovery of 10.55% of original oil in place (OOIP) by water flooding after gel treatment.
Key words:polyacrylamide; gel; sealing characteristic; oil recovery
