渤海油田注水井微压裂解堵技术研究与应用  

Research and Application of Micro-fracture Plugging Removal Technology for Water Injection Wells in Bohai Oilfield

作　　者：柴世超 刘常清 张宁 任宇轩 CHAI Shichao;LIU Changqing;ZHANG Ning;REN Yuxuan(Tianjin Branch,CNOOCCo.,Ltd.,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《天津科技》2024年第8期58-62,共5页Tianjin Science & Technology

摘　　要：渤海油田水处理难度大,虽然采取了很多提升水质措施,但仍存在注入水与储层配伍性问题,导致注水井井筒附近存在储层污染,注水井吸水能力不断下降。酸化是渤海油田采用最多的增注措施,但多轮次酸化后增注效果变差,增注有效期也越来越短。提高注水井吸水能力、满足配注要求并降低解堵成本是渤海油田急需解决的技术难题,为此依托海上平台现有条件,基于高压和大排量注水,对注水井井筒附近污染带进行微压裂,以提高注水井吸水能力。岩芯实验和理论研究表明,疏松砂岩注水井微压裂主要是在注水井井筒附近形成微裂缝,远离污染带,在疏松砂岩储层中裂缝延伸距离有限,这是一种通过解除井筒附近污染带以恢复注水井吸水能力的手段。以上述研究结果为依据,对F8井进行微压裂先导试验,视吸水指数由微压裂前的10 m^(3)/(d·MPa)增加到16.5 m^(3)/(d·MPa),增注效果明显。该技术在渤海油田推广应用161井次,实现了提高注水井吸水能力、满足配注要求并降低解堵成本的目标。Due to the difficulty of water treatment in Bohai Oilfield,although many measures have been taken to improve water quality,there are still compatibility issues between injected water and reservoir,resulting in reservoir damage near the wellbore of the injection well and a continuous decline in the water absorption capacity of the injection well.Acidification is the most commonly used measure for increasing injection in Bohai Oilfield.However,after multiple rounds of acidification,the effect of increasing injection becomes worse,and the effective period of increasing injection becomes shorter.Improving the water absorption capacity of injection wells,meeting the requirements of injection allocation,and reducing the cost of plugging removal are urgent technical problems that need to be addressed in Bohai Oilfield.Based on the existing conditions of offshore platforms and high-pressure and high displacement water injection,micro-fracturing is carried out in the contaminated zone near the wellbore of the injection well in order to improve the water absorption capacity of the injection well.Core experiments and theoretical studies show that micro-fracturing in unconsolidated sandstone water injection wells mainly forms micro-cracks near the wellbore of the injection well,and the crack extension distance is limited in unconsolidated sandstone reservoirs far away from the pollution zone.This is a technical means to restore the water absorption capacity of the injection well by relieving the damage caused by the pollution zone.Based on the above research conclusions,a micro-fracturing pilot test was conducted on Well F8,and the apparent water absorption index increased from 10 m^(3)/(d·MPa)before micro-fracturing to 16.5 m^(3)/(d·MPa),indicating a significant increase in injection efficiency.This technology has been promoted and applied 161 times in Bohai Oilfield,achieving the goal of improving the water absorption capacity of injection wells,meeting the requirements of injection allocation,and reducing the cost of pl

关 键 词：微压裂 储层污染 注水井 吸水能力 疏松砂岩 

分 类 号：TE355[石油与天然气工程—油气田开发工程]