Dlb2 No. Condensate Gas Reservoirs Dry Gas Reinjection Development Technology Policy Research

Gas condensate reservoir is a special type of gas reservoirs. When developed by pressure depletion, then retrograde condensation of heavy components dissolved in the gas phase would cause the magnificent loss of gas condensate which has high economic value. The method of maintaining formation pressure is commonly used to develop a gas condensate reservoir, especially which contains high amount of condensate oil, in order to enhance the recovery of gas condensate.DLB No.2 gas condensate reservoir which contains high amount of condensate oil is developed by depleting formation pressure. At present, its formation pressure is below dew-point pressure and its wells'productivity is declining. On account of low recovery percent of gas condensate, high amount of residual recoverable reserve, large potential of digging exploitation, ample and excessive dry gas quantity, it is planed to inject dry gas to maintain formation pressure in the subsequent exploitation period in order to improve the recovery of condensate oil. Therefore, used gas-engineering methods and combined with geological and dynamic production data, this thesis has made detailed research of technological policy for development of DLB No.2 gas condensate reservoir by dry gas recycling. The main achievements are as follow:(1) It has used the method which had been summarized to evaluate formation pressure under condition of un-shut in to estimate the formation pressure of DLB No.2 gas condensate reservoir. The current formation pressure was below dew-point which indicated that retrograde condensation phenomenon had happened which damaged formation rock, declined productivity and caused loss of retrograde condensate. Thus the necessary of pressure maintenance operation is magnificence.(2) It has appraised productivity of 9 produce wells in DLB No.2 gas condensate reservoir on the basis of produce historical data and analyzed the influence factors of productivity. It then obtained the analytical expression of single point deliverability equation and average deliverability equation which is necessary when researching policy and measures for cycling exploitation development.(3) It has analyzed the feasibility of dry gas recycling in the light of actual conditions of DLB No.2 gas condensate reservoir and put forward 4 sets of injection-production well pattern plan, then analyzed the reasonable injection-production differential pressure and rational quantities and finally optimized the superior injection-production well pattern plan.(4) It has formed a set of researching method associated with technological policy and measures for development of gas condensate reservoir by cycling. It has analyzed pressure system of injection-production, abundant formation pressure, quit flowing pressure and predicted recovery of DLB No.2 gas condensate reservoir, when were developed by dry gas recycling. All of the studies above are referred to when designing development plan of cycling.