Study on Polymer Plugging Mechanism and Plug Removal Method in Sandstone Reservoirs

doi:10.3969/j.issn.1006-6535.2022.03.023

Abstract

Abstract: In order to solve the problem of severe polymer plugging in polymer flooding process in sandstone reservoirs, the polymer plugging radius was determined by the displacement experiment with multi-point pressure measurement of long sand-packed pipe and the reservoir engineering method, and the polymer plugging mechanism was studied by scanning electron microscopy, CT scanning, nuclear magnetic resonance and other methods. The results showed that, polymer plugging mainly occurred at 0-1/4 near the injection end of the sand-packed pipe; a large amount of polymer was adsorbed on the surface of the high-permeability cores, and polymer plugging was mainly caused by adsorption; the pore size of the low-permeability core was small and a great amount of polymer was mechanically captured at the pore throat, and polymer plugging was mainly caused by mechanical capture; compared with that before polymer flooding, the average pore throat radius and average throat coordination number of core after polymer flooding were reduced, with the average pore throat radius reduced from 42.2 μm to 39.9 μm and the average throat coordination number reduced from 3.36 to 3.19. Based on the study results of plugging radius and location, the field test of plug removal was implemented. The apparent water injectivity index after plug removal was 10.5 times that before plug removal, meeting the injection requirements. The results of the study provide theoretical guidance for studying the polymer plugging mechanism in sandstone reservoirs and the field test of polymer flooding.

Key words: polymer flooding, plugging location, plugging radius, plugging mechanism, unplugging, sandstone reservoir

CLC Number:

TE357.46

Zhao Lin, Gao Shenling, Chen Yuan, Mei Dongfeng, Hou Baofeng, Wang Rui, Li Xindan. Study on Polymer Plugging Mechanism and Plug Removal Method in Sandstone Reservoirs[J]. Special Oil & Gas Reservoirs, 2022, 29(3): 156-161.

References

[1] 瞿朝朝,李彦来,王立垒,等.海上聚合物驱油藏堵塞位置定量表征方法[J].断块油气田,2019,26(3):360-363.
QU Zhaozhao,LI Yanlai,WANG Lilei,et al.Quantitative characterization methods of plugging position of offshore polymer flooding reservoir[J].Fault-Block Oil & Gas Field,2019,26(3):360-363.
[2] 朱贵宝.注聚井解堵增注技术研究[D].大庆:大庆石油学院,2007.
ZHU Guibao.Study on plugging removal and injection stimulation technology in polymer injection wells[D].Daqing:Daqing Petroleum Institute,2007.
[3] 曾明友.海上油田注聚井高效解堵技术研究[D].成都:西南石油大学,2013.
ZENG Mingyou.Study on efficient plugging removal technology of polymer injection well in offshore oil field[D].Chengdu:Southwest Petroleum University,2013.
[4] 李渊.XX油田注聚后产量递减因素及对策研究[D].青岛:中国石油大学(华东),2017.
LI Yuan.Study on factors of production decline and treatment measures after polymer flooding for XX Oilfield[D].Qingdao:China University of Petroleum(East China),2017.
[5] 付美龙,龚波涛,胡泽文,等.真35断块储层渗透率与KY聚合物相对分子质量的匹配性研究[J].油田化学,2016,33(4):677-681.
FU Meilong,GONG Botao,HU Zewen,et al.Research on compatibility between permeability of Zhen35 Fault Block reservoir and KY polymer molecular weight[J].Oilfield Chemistry,2016,33(4):677-681.
[6] 陈磊,赵健,申金伟,等.注聚井堵塞动态过程研究[J].石油化工应用,2020,39(4):40-43.
CHEN Lei,ZHAO Jian,SHEN Jinwei,et al.Study on plugging dynamic process of polymer injection wells[J].Petrochemical Industry Application,2020,39(4):40-43.
[7] 高尚,刘义刚,兰夕堂,等.渤海油田注聚合物井堵塞物组分分析及相互作用机理[J].油田化学,2020,37(2):340-343.
GAO Shang,LIU Yigang,LAN Xitang,et al.Component analysis and interaction mechanism of fouling in polymer flooding well in Bohai Oilfield[J].Oilfield Chemistry,2020,37(2):340-343.
[8] 孟中华,刘平礼,吴媛媛,等.聚合物的静态吸附机理研究[J].石油天然气学报,2010,32(6):315-318
MENG Zhonghua,LIU Pingli,WU Yuanyuan,et al.Study on static adsorption mechanism of polymers[J].Journal of Oil and Gas Technology,2010,32(6):315-318.
[9] 苑玉静,刘义刚,韩玉贵,等.渤海注聚油田储层堵塞、产液下降机理分析及调整措施[J].精细与专用化学品,2020,28(1):30-35.
YUAN Yujing,LIU Yigang,HAN Yugui,et al.Mechanism analysis and adjustment measures of reservoir blockage and production decline in Bohai Field[J].Fine and Specialty Chemicals,2020,28(1):30-35.
[10] 秦同洛.实用油藏工程方法[M].北京:石油工业出版社,1989:25-30.
QIN Tongluo.Practical reservoir engineering methods[M].Beijing:Petroleum Industry Press,1989:25-30.
[11] 李鹏,周承诗,吴琼,等.注聚区油水井用解堵剂和保护剂的研制及评价[J].精细石油化工进展,2011,12(1):1-4.
LI Peng,ZHOU Chengshi,WU Qiong,et al.Development and evaluation of block removing agent and anti-adsorbing agent for polymer injection area oil well[J].Advances in Fine Petrochemicals,2011,12(1):1-4.
[12] SABOORIAN-JOOYBARI H,DEJAM M,CHEN Z.Heavy oil polymer flooding from laboratory core floods to pilot tests and field applications:half-century studies[J].Journal of Petroleum Science and Engineering,2016,142:85-100.
[13] JUNG J C,ZHANG K,CHON B H,et al.Rheology and polymer flooding characteristics of partially hydrolyzed polyacrylamide for enhanced heavy oil recovery[J].Journal of Applied Polymer Science,2013,127(6):4833-4839.
[14] LEE K S.Effects of polymer adsorption on the oil recovery during polymer flooding processes[J].Petroleum science and technology,2010,28(4):351-359.
[15] PARK H,HAN J,SUNG W.Effect of polymer concentration on the polymer adsorption-induced permeability reduction in low permeability reservoirs[J].Energy,2015,84:666-671.
[16] KAMAL M S,SULTAN A S,AL-MUBAIYEDH U A,et al.Review on polymer flooding:rheology,adsorption,stability,and field applications of various polymer systems[J].Polymer Reviews,2015,55(3):491-530.
[17] PARK H,HAN J J,LEE M,et al.Experimental investigation of polymer adsorption-induced permeability reduction in low permeability reservoirs[J].Journal of Petroleum & Environmental Biotechnology,2014,5(4):1000183.
[18] 孟向丽,赵立强,徐昆,等.注聚合物井堵塞原因和解堵技术[J].石油钻采工艺,2011,33(3):70-73.
MENG Xiangli,ZHAO Liqiang,XU Kun,et al.Reason analysis on plugging in polymeric damaged well and the technology of broken down[J].Oil Drilling & Production Technology,2011,33(3):70-73.