气举井组及油田优化配气方法研究

APPROACH FOR OPTIMIZATION OF GAS ALLOCATION TO A GROUP OF WELL AND OILFIELD IN ARTIFICIAL LIFT

概述了气举井组优化配气的发展现状,分析了各种类型的气举特性曲线的特点。考虑到现场的实用性和合理性,将单井最大产油量值前的气举特性曲线数据拟合为二次多项式方程,并定义井组特性曲线为井组注气量与井组最大产油量的关系曲线。完善了井组优化配气模型并建立了油田优化配气非线性数学模型,并提出了一种求解非线性优化配气模型的新方法——惩罚函数法,为了提高模型的求解速度,提出了一种估计初始注气量的新方法——最大配气量法。惩罚函数法能处理等式约束与不等式约束,收敛速度通常只受初始注气量的影响。应用提出的新方法求解了井组及油田配气数学模型,并给出优化配气算例。

The paper summarizes the current status of the optimization of gas allocation to a group of wells, and analyzes the characteristics of all types of the gas - lift performance curves. Considering the practicability to fields and the rationality, the paper fits the scattered points ahead of maximum value in the gas lift performance curve as quadratic equation. The well group performance curve is defined as the relationship between the gas in-jection rate and the maximum oil production rate. The paper consummates the well group optimization model of gas allocation and develops the oilfield optimization model of gas allocation, and gives a new method as well penalty function to solve the non-linear optimization model of gas allocation. To improve solving the rate of the model, a new approach named maximum gas allocation is proposed to guess the initia! gas injection rates. The penalty function is capable of accommodating both the equality constraints and the inequality constraints. As a rule, the convergence rate is affected only by an initial guess for the gas injection rates. By using the new method, the paper puts forward the well groups, and oilfield gas allocation model is solved and the example was provided in the end.