渤海S油田窜流通道封堵技术

Plugging Technology of Channeling in Bohai S Oilfield

针对渤海S油田长期注水开发形成水窜通道,导致区块含水上升速度快的问题,采用示踪剂方法识别油水井间高渗条带,分析计算了高渗条带渗透率及孔喉大小,通过对凝胶类调剖体系强度和微球粒径分级、微球类调剖体系粒径与岩心孔喉直径的匹配性和注入段塞及施工工艺组合方式的研究,获得了适合该油田高渗条带封堵及深部调剖的分级组合深部调剖技术。该技术的主要内容包括:以凝胶(先注弱凝胶,后注强凝胶)加微球为组合调剖剂,以凝胶井口调剖加微球在线调剖的组合工艺方式。研究结果表明,S油田目标井区高渗条带渗透率为8.8μm^2,平均孔喉约为20μm;适合分级组合深部调剖技术的两种强度凝胶体系配方为0.3%聚合物+0.2%交联剂(弱凝胶)、0.4%聚合物+0.3%交联剂(强凝胶);微球膨胀后的粒径与孔喉直径比为1~1.5时,微球调剖体系兼具良好的封堵性能和运移性能;应用凝胶封堵近井地带高渗条带、微球进行深部调剖的段塞组合方式,在相同成本下的调剖效果最好;采用井口调剖+在线调剖相结合的工艺方式,可使海上油田深部调剖设备占用平台空间降低70%以上。分级组合深部调剖技术在渤海S油田矿场试验中取得了显著效果,井组综合含水最高下降8.4%,井组净增油18288 m^3,适合于海上砂岩油田深部调剖作业。

Water channeling due to long-term water flooding led to rapid water cut rise in Bohai S oilfield. Tracer test was used to identify water channeling between oil and water wells, and channeling permeability and pore-throat sizes were calculated. Strength classification of gel profile control system, size classification of polymer microsphere, matching of microsphere size and core throat diameter, and combination of injection slug and crafts were studied. The classified combination of deep profile control technology for deep profile control in Bohai S oilfield was determined. The technology included a combination of the gel （first injecting weak gel and then injecting strong gel） and microspheres, and a combination of gel wellhead profile control and microsphere on-line profile control. The results showed that the permeability of high permeability zone was 8.8 μm^2 and the average pore throat was about 20μm in Bohai S oilfield. Two kinds of gel systems which included 0.3% polymer＋0.2% crosslinking agent （weak gel） and 0.4% polymer＋0.3% crosslinking agent （strong gel） were suitable for the classified combination of deep profile control technology. When the diameter ratio of expanded microsphere and pore throat was 1 to 1.5, the microsphere profile control system had good sealing and migration performance. In the same cost, slug combination that gel sealing high permeability belt near the wellbore and microsphere for deep profile control had the best effect. The space of deep profile control equipment in offshore oilfield was reduced by more than 70% with combination of wellhead and on-line profile control. The effect of field test was remarkable in Bohai S oilfield, using the above selected profile control system could lead to a decrease of 8.4% in water cut and a increase of 18288 m^3 in oil production. The classified combination of deep profile control technology was suitable for the deep profile control in offshore sandstone oilfield.