Study on cyclic gas injection technology for development of Dalaoba condensate field in Tarim basin

During production tail of Dalaoba condensate field,formation pressure drops below dew point pressure and condensate oil sequently drops out,causing declined fluid recovery.For the purpose of recovery enhancement,study on cyclic gas injection tech-nology is carried out.Based on the analysis of geologic characteristics and fluid phase features,this paper concludes that gas injection is applicable for Dalaoba condensate field.And it is better to inject gas to keep up the pressure in such condensate gas reservoir during the course of constant volume depletion.Therefore,the equation for fluid productivity and injectivity in individual well is established and gas injection scheme is optimized by using mature well and newly drilled well.Through studies,the pattern of well for cyclic gas injection in condensate gas reservoir is finalized,the development index of cyclic gas injection is pre-determined and a complete system of cyclic gas injection technology for condensate gas reservoir is formed.Comparing the development index from cyclic gas injection simulation with that by natural depletion,it is found that condensate oil recovery by cyclic gas injection is greatly enhanced.As a result,the conclusion is drawn that cyclic gas injection technology is feasible for condensate gas reservoir development.