水平井砾石充填过程中的变质量流

由于携砂液向地层的滤失以及通过筛管缝隙的流体质量交换,水平井砾石充填过程中冲筛、井筒环空两个流动系统均为复杂的变质量流。考虑变质量流特征,分别建立井筒环空、冲筛环空两个独立流动系统的砾石、携砂液的质量和动量守恒方程,以及各系统间的流动耦合方程,得到水平井砾石充填过程中的变质量流动数学模型。数值求解后可计算压力、流量、窜流量、滤失量等随时间和位置的变化规律,为水平井砾石充填的优化设计提供基础。

Variable Mass Flow during Gravel-packing in Horizontal Wells

During the process of gravel-packing in horizontal wells, there are the filtration flow of the carrier fluid to the formation and the exchange flow through the screen slots. As a result, the flows in wash-pipe-screen annular and wellbore annular all are complicated variable mass flow. Considering these characteristics, the mass and momentum conservation equations of gravel and fluid are established for two flow systems, that is, solid-fluid two phase flow in wellbore annular and single phase flow in wash pipe and screen annular. With the coupling equations of the two flow systems, the mathematical model for variable mass flow in horizontal gravel-packing is evolved. The model can be numerically solved and used to calculate such parameters as pressure, flow rate? exchange flow rate and filtration flow rate varying with time and location, which offers the basic foundation for the design optimization of horizontal gravel-packing.