考虑水锁损害的致密砂岩气藏产能分析  

Productivity analysis of tight sandstone gas reservoirs considering water blocking damage

作　　者：杨旭[1] 孟英峰[1] 李皋[1] 曾辉[1] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500

出　　处：《天然气地球科学》2017年第5期812-818,共7页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2016ZX05021-004);国家自然科学基金项目(编号:51674217)联合资助

摘　　要：致密砂岩气藏在钻井、完井和储层改造过程中容易受到水锁损害,影响气井产能。基于对流扩散模型,分析了液相侵入深度随时间的变化。基于Forchheimer渗流方程,建立了考虑水锁损害的致密砂岩气藏直井二项式稳态产能模型。分析了紊流效应、启动压力梯度、渗透率应力敏感和水锁损害范围及其程度对气井产能的影响。结果表明水锁损害造成液相侵入区气相渗透率减小,导致井周压降梯度和启动压力梯度显著增加。水锁损害造成的产气量降低远大于非达西效应、启动压力和应力敏感的影响。液相侵入初期造成的气井产量降低最为明显,随液相侵入深度的增加,产气量先急剧降低,然后趋于平缓。水锁损害范围和损害程度越大,气井产量降低越多。Tight gas reservoirs can be subject to water blocking damage due to liquid invasion during well drilling,completion,and stimulation processes.Water blocking is one of the major reasons of low production in tight sandstone reservoirs.Variation of liquid invasion depth was calculated based on the Darcy equa tion and convection-dispersion model. The productivity formula for the vertical wells considering water blocking damage was developed on the basis of the Forchheimer binomial equation.The influences of inertia effect, starting pressure gradient, stress sensitivity, water blocking damage degree and damage range on gas well productivity were studied.The results indicate that water blocking damage decreases the relative permeability of gas in the liquid invasion zone.It also leads to additional pressure drop and starting pressure gradient in the near wellbore region.The effect of water blocking damage on gas production is more serious than that of inertia turbulent effect, starting pressure gradient and stress sensitivity.Water blocking damage causes large reduction in gas well productivity, and the effect of liquid invasion on gas production is more obvious in the initial period of liquid invasion. With the increases in liquid invasion depth, gas production presents an initial rapid decrease,followed by a slow and steady decrease.The production of tight gas wells decreases with the increase of water blocking damage range and degree.

关 键 词：致密砂岩 液相侵入 水锁损害 启动压力 产能 

分 类 号：TE312[石油与天然气工程—油气田开发工程]