潜山油藏气窜识别方法的建立与应用

Establishment and application of gas channeling identificationmethods in buried hill oil reservoirs

裂缝性潜山油藏为典型的双重介质油藏,积极开展注气提高采收率研究对开发这类油藏具有重要意义.针对气驱开发过程中存在的气窜问题进行研究,以兴隆台裂缝性潜山油藏为例,建立双重孔隙介质油藏数值模拟模型,基于数值模拟方法,分析不同气窜方向的生产气油比特征曲线,分析、确定实际生产井发生气窜的来源及形成气窜的时间,从而建立一种新的、成本低、操作简便的潜山油藏气窜识别方法.利用该识别方法对兴古7潜山油藏实际气窜井7-H2井进行识别,结果表明:不同气窜类型存在不同气油比导数曲线特征,底部气窜气油比及导数曲线特征可分为5个阶段,气窜形成于第三阶段,形成气窜之后气油比导数曲线明显向下;顶部气窜气油比及导数曲线特征可分为3个阶段,气窜形成于第三阶段,导数曲线明显向上;横向气窜气油比及导数曲线特征可分为3个阶段,气窜形成于第三阶段,导数曲线基本保持水平.7-H2井在425天左右发生气窜,导数曲线明显向下,气窜类型属于底部气窜.经气体示踪剂监测方法验证,识别结果与实际油井的气窜情况分析一致,证明该识别方法具有良好的准确性及可靠性,能够有效识别气窜来源,为针对性的减缓气窜调控措施提供了有力支持.

The fractured buried hill reservoir is a typical dual-medium reservoir.Active research on gas injection and enhanced oil recovery is of great significance for the development of such reservoirs.Aiming at the problem of gas channeling in the development of gas flooding,taking the fractured buried hill reservoir in Xinglongtai as an example,the numerical simulation model of dual-porosity reservoir is established.Based on the numerical simulation method,the gas-oil ratio in different gas channeling direction is analyzed.The characteristic curve is used to analyze and determine the source of gas channeling in the actual production well and the time to form the gas channeling,so as to establish a new,low-cost and easy-to-use gas channeling identification method for the buried hill reservoir.The identification method is used to identify the actual gas well 7-H2 well in Xinggu 7 buried hill reservoir.The results show that different gas channeling types have different gas-oil ratio derivative curve characteristics:The characteristics of bottom gas channeling gas-oil ratio and derivative curve can be divided into five stages,the gas channeling is formed in the third stage,and the gas-oil ratio derivative curve is obviously downward after the formation of gas channeling;the top gas channeling gas-oil ratio and derivative curve characteristics can be divided into three stages,the gas channeling is formed in the third stage,the derivative curve is obviously upward;the transverse gas channeling gas-oil ratio and derivative curve characteristics can be divided into three stages,the gas channeling is formed in the third stage,and the derivative curve is basically maintained.In the 7-H2 well,the gas channeling occurred at about 425 days,the derivative curve was obviously downward,and the gas channeling type belonged to the bottom gas channeling.It is verified by the gas tracer monitoring method that the identification result is consistent with the analysis of the actual well's gas channeling condition,which proves that the identification method has good accuracy and reliability,can effectively identify the source of gas channeling,and provides strong support for targeted measures to reduce gas channeling.