Optimization Of Intermittent Gas Lift Production In Tight Sandstone Gas Wells

Since tight sandstone gas is one of the unconventional oil and gas resource with high development potential,its efficient development is crucial to China’s energy security.However,gas wells generally produce intermittently due to fluid accumulation in the wellbore and insufficient formation pressure during the middle and late stages of the development.Currently,the intermittent production regime is mainly determined by field experiment,thus itis urgent to establish a production optimization method based on the dynamic response mechanism of "fluid accumulation-drainage-production" to improve the recovery factor of tight sandstone gas.In this paper,the reasons for intermittent production of gas wells is firstly analyzed,then a model for calculating the physical parameters of fluid accumulation,wellbore pressure gradient and fluid accumulation height based on the fluid accumulation law for water producing gas wells has been proposed and validated.After that,based on the mass,momentum and energy equations of oil casing,an intermittent gas lift drainage model is developed,solved by using Eulerian discretization,and the relationship between the oil pressure at the intermittent gas lift wellhead and the intermittent gas lift injection,drainage and gas production is analyzed.Finally,taking the S well as an example,its accumulation height and drainage time under different oil casing pressure differentials were calculated by using the gas wellbore accumulation-drainage model,and the optimization of the working system has been carried out.This method provides guidance for optimizing the intermittent gas lift production system for gas wells with fluid accumulation in tight sandstone.