Abstract:

Radial multilateral horizontal well technology can be used to improve the productivity of low permeability reservoirs by drilling multilateral branches in the oil intervals of horizontal wellbores，which increases the oil displacement area. However，the factors affecting the productivity of radial multilateral horizontal wells are not clear and，to date，there has been little research on methods of prediction. This paper describes a numerical model for radial multilateral horizontal wells，using numerical simulation software COMSOL，and its application in evaluating the influence of factors such as reservoir and well type on well production. The mathematical model was solved using the finite element method and radial horizontal well output predicted using the material balance method. The focus of the study is to analyze the effects of changes in radial multilateral well parameters and formation heterogeneity on production behavior and transient pressure distribution. The results show that branch length has a significant effect on productivity，effectively expanding the control area. The number of branches，their angles，and formation heterogeneity，are found to be the principal controlling factors.

Key words:

low permeability reservoir, radial multilateral horizontal well, branch well, numerical simulation, finite element

摘要：

径向多分支水平井是指在水平井筒的油层段钻出多个分支井以扩大驱油面积的一种提高低渗油藏产能的技术。目前针对径向多分支水平井产能预测方法的相关研究较少，产能影响因素尚不明确。采用数值模拟软件COMSOL建立了径向多分支水平井数值模型，评价了储层和井型因素对产量的影响。采用有限元法对数学模型进行数值求解，采用物质平衡法计算产量；分析了径向多分支井参数和地层非均质性对生产行为和瞬态压力分布特征的影响。研究结果表明，分支井长度对产能影响明显，能够有效扩大控制区面积，分支井个数、角度和地层非均质性在一定程度上为产能主控因素。

关键词:

低渗透油藏, 径向多分支水平井, 分支井, 数值模拟, 有限元