尼日利亚AKPO深水油田储层保护完井液技术

尼日利亚AKPO深水油田完井作业中存在环境温度低、海底页岩易失稳、易形成气体水合物等一系列问题,而现用完井液由于滤失量过高,导致储层受到不同程度的损害。为此,根据储层特点和潜在伤害因素,通过优选关键处理剂,针对不同的完井方式,优选出了适合于深水钻井并有利于储层保护的3种完井液。性能评价结果表明,与现场常用完井液相比,优选出的完井液具有良好的流变性和黏土水化抑制性,滤失量小,能有效抑制气体水合物生成,与储层流体配伍性好,储层岩心在完井液污染后渗透率恢复率均达到85%以上。现场应用发现,采用优选完井液完井的AKPO-302井的表皮系数只有0.25,而采用现用完井液完井的AKPO-1井和AKPO-2井个别井段的表皮系数高达100,表明优选完井液的保护储层效果显著。 

Completion Fluids with Low Formation Damage in AKPO,Nigeria

During deepwater well completion in AKPO,Nigeria,low temperature,shale instability,formation of gas hydrate and other factors often cause problems.Because of high-rate filter loss,current completion fluids lead to formation damages to different degrees.Based on reservoir characteristics and potential damage factors,this paper selected key treatment agent and optimized three different formation-friendly deep water completion fluids which are prepared for different well completions.The performance evaluation results showed that,the optimized systems had better properties in rheological behavior,filter-loss reduction,clay hydration inhibition and gas hydrate inhibition,compared with current completion fluids.The reservoir core permeability recovery rate reached over 85%.Field application showed that the skin factor of AKPO-302 completed with optimized fluids was only 0.25,while in some intervals of Well AKPO-1 and Well AKPO-2,the skin factor reached 100.The results proved the completion fluids had remarkable reservoir protection results.