Research On Mechanism And Dynamic Analysis Method Of Hydrous Condensate Gas Reservoir Developed By Cyclic Gas Injection

Condensate gas reservoir with layered edge water body will face many problems in the process of depletion exploitation,such as gas well producing water and gas well deliverability fast attenuation.If we want to improve condensate oil recovery,the reservoir need to switch to produce in circulating gas injection mechanism.This paper took D condensate gas reservoir as example.Since 2005,the reservoir has been producing in natural depletion with high production and stable yield for nine years.Then,the reservoir switched to producing in circulating gas injection mechanism for three years.After gas injection,the dynamic change characteristics,effect and gas channeling condition of production wells are lack of systematic knowledge and evaluation.Meanwhile,Reservoir distribution of oil and gas,retrograde condensation and water production status have been changed after three years of gas injection.Gas injection volume needs to be optimized again.In this paper,based on the actual production dynamic data,the gas reservoir engineering are studied and the characteristics of formation pressure,retrograde condensation and water breakthrough are analyzed.It also analyzed and summarized the change of oil pressure,gas oil ratio,condensate content and other parameters.According to gas channeling mechanism and gas channeling identification method,it also studied on the future gas channeling,and predicted the gas channeling by plot method.Last,through the numerical simulation of typical blocks and real geological model,it studied the desirable development of circulating gas injection and reasonable note of gas.This paper studied parameter variation of gas injection effect,established the chart for forecasting gas channeling,studied that the reasonable injection production method is regular shut-in and the reasonable note of air for follow-up stage is 200000m3/day.The parameter variation and chart for forecasting gas channeling will provide reference and guidance for evaluation of gas injection effect and identification of gas channeling in the future.And the reasonable note of air for follow-up stage will lead to the optimization of oil recovery in the future.