努拉里边底水油气藏提高采收率注采制度优化方法

开发边底水油气藏关键因素是抑制边底水锥进,延长油井无水采油期以提高油藏采收率,因此需要设置合理的开采速度和油水井注采制度.为深入了解不同井网系统和注采参数对边底水油气藏开发效果的影响程度,针对努拉里边底水油气藏开展研究.对边底水影响程度进行研究,得到各井在改变水体倍数后,以含水率差值4%为界限定义受边底水影响程度强弱,差值超过4%则定义为强水侵井,反之则为弱水侵井.在此基础上,采用油藏工程和数值模拟方法优选了注采参数,得出最优井距为1000m,最佳日注水量为30m³/d,最佳采液速度为4.75%-5%,并对优化参数进行了模拟预测,优化后累计产油量增加1.98×10⁴t,采收率达到54.7%.运用油藏工程方法对优化后的开发方式调整进行了分析,结果表明:可采储量采出程度小于62.78%时应以扩大波及体积为主,大于62.78%后应以增加驱油效率为主,目标区块优化后可采储量采出程度达到71.3%,相对潜力值i=0.81<1,处于开发后期,此时开发方式应以提高驱油效率为主.研究成果为同类边底水油气藏前期开发和后期措施调整提供了理论指导和借鉴.

Optimization Method of Injection-production System for Enhanced Oil Recovery in Nurali Edge Bottom Water Reservoir

The key factors of developing edge-bottom water reservoirs are to restrain edgebottom water coning and prolong the water-free production period of oil Wells in order to improve reservoir recovery.Therefore,it is necessary to set reasonable production rate and injection and production system of oil and water Wells.In order to understand the influence of different well pattern systems and injection and production parameters on the development effect of border-bottom water reservoir,the Nulali border-bottom water reservoir was studied.The influence degree of edge-bottom water was studied,and it was found that after changing the water multiple of each well,the influence degree of edge-bottom water was defined with the difference of water cut of 4%as the limit.If the difference was more than 4%,it was defined as strong water invasion;otherwise,it was defined as weak water invasion.On this basis,reservoir engineering and numerical simulation methods were used to optimize the injection and production parameters,and the optimal well spacing was 1000 m,the optimal daily water injection rate was 30 m³/d,and the optimal fluid recovery rate was 4.75%-5%.The simulation and prediction of the optimization scheme were carried out.After optimization,the cumulative oil production increased by 1.98×10⁴t,and the recovery factor reached 54.7%.Using reservoir engineering method for the optimized way of development adjustment are analyzed,the results show that the produced degree of recoverable reserves is less than 62.78%when should give priority to in order to enlarge sweep volume,more than 62.78%after should give priority to in order to increase the oil displacement efficiency,the optimized target blocks produced degree of recoverable reserves reached 71.3%,the relative potential value i=0.81<1,late in development,development way at this time should give priority to in order to improve the oil displacement efficiency.The research results provide theoretical guidance and reference for the earlier development and later measure adjustment of similar edge-bottom water reservoirs.