底水油藏水平井控流完井数值模拟耦合模型

为了预测控流完井条件下底水油藏水平井生产动态并设计关键控流参数,以数值模拟方法为数学求解手段,建立三维空间油水两相混合网格耦合模型,引入"拟传导率"概念,使得耦合模型中包含的油藏渗流、井筒管流和筛管控流3种数学模型可写成统一线性数学表达形式,从而方便建立大型线性方程组求解。结果表明:拟传导率反映相邻网格之间井筒管流或筛管控流流动过程中某相流体流量和压降的比率,流体流动阻力越大,则拟传导率越小,反之亦然;相比常规裸眼井下滤砂管完井,用耦合模型设计控流参数的控流完井方法使得实例井流入流率剖面、油藏渗流压降剖面、水脊前缘上升剖面和见水时间剖面更加均衡,见水时间大幅延长。

A new numerical coupling model of horizontal well completed with flow control method in bottom water reservoir

A new 3D hybrid grid model for oil-water two-phase was built, in which numerical simulation was carried out to forecast production performance of a bottom water reservoir with horizontal wells completed using a flow control technique. The new model consists of reservoir flow, wellbore flow and ICD pipe flow control models. A parameter of "pseudo conductivity" was defined in order to linearize the flow in wellbore and ICD pipe and to unify the mathematical expressions of all the three flow models, and then a system of linear equations coupling with the three flow models can be readily established and solved. The pseudo conductivity parameter is calculated as the ratio of the flow rate versus pressure drop for a certain fluid phase passing through adjacent grids by wellbore flow or the controlled flow through ICDs. The simulation results of a case study show that, the larger the flow resistance is, the smaller the pseudo conductivity will be, and vice versa. In comparison with the conventional open hole sand control completion method, the flow control method can greatly delay water breakthrough time by improving the performance of inflow and reducing the pressure drop in near wellbore region. The new model can provide a theoretical guidance for the design and application of the flow control completion method.