封闭性凝析气藏开发指标预测新方法

A new method for forecasting development indexes of closed condensate gas reservoirs

中低含凝析油的气藏多采用衰竭式开发,其开发指标同时受到地下能力和下游市场两个方面的限制,开发指标预测难度大。通过实际生产动态资料分析并结合物质平衡理论,考虑组分变化后形成衰竭开发的封闭性凝析气藏动态规律性认识;基于典型凝析气藏试井资料分析,建立了气井无阻流量随地层压力变化的定量预测图版;兼顾地下能力与市场需求两个方面,建立了一种更为合理的封闭性凝析气藏衰竭开发的指标量化评价方法,为此类气藏的现场生产提供更为有力的指导。研究表明:(1)由于受到组分变化的影响,凝析气藏衰竭开发过程中地层压力多呈两段式递减,随着地层压力下降,气井的绝对无阻流量呈指数递减;(2)衰竭式开发的封闭凝析气藏开发前期主要受到下游市场约束,后期主要受到地下能力的限制;(3)研究方法考虑因素全面,评价结果更为准确合理,可以为后续生产决策提供更为准确可靠的支撑。

Condensate gas reservoir with medium and low condensate oil content are mostly developed in depletion mode,and their development indicators are restricted by both the underground capacity and the downstream market,and it is difficult to predict the development indicators.Through the analysis of actual production performance data and combined with the material balance theory,the understanding of the dynamic regularity of a depleted condensate gas reservoir is formed after considering the composition changes,based on the analysis of typical condensate gas reservoir well test data,the open flow rate of the gas well is established.Quantitative prediction chart of pressure changes,taking into account both underground capacity and market demand,a more reasonable quantitative evaluation method for the depletion development of closed condensate gas reservoirs has been established,which provides more information for the on-site production of such gas reservoirs.Studies have shown that,(1)Due to the influence of changes in composition,the formation pressure of condensate gas reservoirs decreases in two stages during the depletion development process.As the formation pressure decreases,the absolute open flow rate of the gas well decreases exponentially.(2)The closure of depletion development,the early stage of condensate gas reservoir development is mainly restricted by the downstream market,and the later stage is mainly restricted by the underground capacity.(3)The research method considers comprehensive factors,and the evaluation results are more accurate and reasonable,which can provide more accurate and reliable support for subsequent production decisions.