水平气井井筒压降及产量变化规律研究

对于水平井开发气藏，其生产系统由气藏渗流和水平气井井筒内流动两部分所组成。过去人们忽视水平气井井筒中的压降，给水平气井的生产系统分析带来较大的误差。文章首先利用采气指数的概念，分别建立了气藏渗流及水平气井井筒流动的数学模型，然后应用体积平衡原理将气藏渗流和水平气井井筒流动联系起来，在层流、光滑管壁紊流及粗糙管壁紊流流态下，推导出水平气井井筒压降和产量分布的表达式，实例计算和分析了一口水平气井井筒的压力和产量变化规律。为水平气井的生产系统分析提供了理论基础。

VARIATION LAW OF PRESSURE DROP AND PRODUCTIVITY RATE IN HORIZONTAL GAS WELL

As for the gas reservoirs developed with horizontal wells,the production system is consisted of the flow through porous media in the gas reservoirs and the flow in the wellbore of the horizontal well.Pressure drop in horizontal well used to be ignored which results in bigger error in analyzing production system of horizontal wellbore.In this paper,mathematical models of flow through porous media and the flow in horizontal gas wellbore are established by using the concept of production index,then,by means of the volume balance principle,the flow in the gas reservoir is correlated with the flow in the horizontal wellbore,in case of covering flowing states of laminar flow,velvet turbulence and granulate turbulence,the relational expression of pressure drop and productivity with position variation is derived for horizontal wells of the gas reservoir.As an example,the variation law of wellbore pressure and productivity for a horizontal well in a gas reservoir are calculated and analyzed.This article presents a theoretical basis for analyzing production system of horizontal well.