基于增广拉格朗日乘子法的水平井射孔密度分布研究

合理的孔眼密度分布能改善水平井入流剖面,有利于延缓水、气锥进。考虑水平井井筒内摩擦损失和加速损失的影响,基于Landman油藏渗流模型,建立了以孔眼位置为优化设计变量、均匀入流剖面为约束条件、水平井产量或生产压差为目标函数的射孔优化模型。采用增广拉格朗日乘子法对有限导流水平井的射孔密度分布进行优化研究。优化结果表明,为获得尽可能均匀的入流剖面,沿水平井跟端向指端方向射孔密度逐渐增加,约在井筒长度的3/5位置附近取得最大值,在趾端处降低;均匀入流剖面下的产量较均匀射孔水平井的产量低。

Augmented Lagrange Multiplier Method for Perforation Optimization of Horizontal Wells

Reasonable perforation is of great benefit to ameliorate the inflow profile,and further stabilize the production and control the water cut for perforated horizontal wells.Considering the effect of friction and acceleration losses on pressure drop along the wellbore,based on the Landman model of steady state inflow,optimization models are presented,in which production or drawndown pressure was treated as an objective function,positions of perforations as the decision-making variable,and uniform inflow profile as constraint.Perforation density distribution of the finite conductive well was studied by virtue of augmented Lagrange multiplier method with rapid convergence and high precision.The results indicate that the uniform inflow profile requires that perforation density increases gradually from the heel towards the toe of the horizontal well,reaches its maximum value near the position a distance from 3/5 length of the wellbore,and then decreases.The results also show that the production obtained under the condition of uniform inflow rate profile is less than that produced by the well perforated uniformly.