裂缝性气藏采收率影响因素数值模拟——以塔里木盆地博孜大北气田为例

Numerical Simulation of Factors Affecting the Recovery of Fractured Gas Reservoirs:Taking of Bozi-Dabei Gas Field,Tarim Basin as an Example

博孜-大北区块油气资源丰富,开发潜力巨大。由于目的层埋藏深度大、构造复杂、断裂裂缝发育、储层致密、温度压力高、水体分布复杂且活跃,气藏开发特征差异大,部分气藏水侵速度快,严重影响气藏开发效果和最终采收率。在确定八种主要影响采收率因素的基础上,数值模拟分析了各因素对采收率的影响,并运用灰色关联度模型进行了权重排序。研究结果表明,裂缝发育程度、气藏幅度、治水对策/排水规模、废弃压力、井网密度对采收率影响较大,气藏厚度、水体大小、采气速度、井网井型对采收率影响较小,其中采气速度、治水对策及排水规模、井网井型及布井方式属于人为可控因素,可通过控制措施达到最佳开发效益;废弃压力属于可变因素,可通过工艺措施降低废弃地层压力以提高采收率。气藏采收率影响因素权重分析为气藏高效开发提供了实施依据。

Boz-dabei gas field is rich in oil and gas resources and has great potential for development.Due to the large burial depth,complex structure,fracture development,tight reservoir,high temperature and pressure,complex and active water distribution of the reservoir,the development characteristics of the gas reservoir are very different,and the water penetration rate of some gas reservoirs is fast,which seriously affects the development effect of the gas reservoir and the final recovery efficiency.On the basis of determining eight main influencing factors(fracture development degree,gas reservoir amplitude,drainage scale,abandonment pressure,well pattern density,gas reservoir thickness,water body size,gas production speed,and well pattern type),the influence of each factor on the recovery efficiency through numerical simulation was analyzed,the grey correlation degree model to sort the weight was used,and the influencing factors of gas reservoir recovery efficiency were analyzed.The results show that the fracture development degree,gas reservoir amplitude,water control strategy/drainage scale,abandonment pressure and well pattern density have great influence on the recovery efficiency,while the gas reservoir thickness,water body size,gas production speed and well pattern type have little influence on the recovery efficiency.Among them,gas production speed,water control strategy and drainage scale,well pattern and well layout are human controllable factors,which can be controlled to achieve the best development benefits.The abandoned formation pressure is a variable factor,and various processes can be used to reduce the abandoned formation pressure to improve oil recovery.The weight analysis of gas reservoir recovery factor provides a theoretical basis for improving oil recovery and efficient gas reservoir development.