The Development Characteristics And Comprehensive Adjustment Plan Research Of Kekeya Gas Condensate Reservoir

With continuously gas field exploitation every year of Kekeya, the various contradictions and problems gradually emerged out. The major problems and difficulties of the reservoir are as follows: ①The remaining high-quality reserves are small and it’s difficult to keep stable production. ②The early research data is relatively fragmented and the knowledge of reservoir properties is not enough. ③ Kekeya has been developed for 30 years, now it is in the late stage of development. Rich region of remaining oil and gas with high quality in the main oil and gas zones is difficult to determine, and the adjustment room is small. Besides, the formation pressure is low, the downhole conditions is complex. As a result it is difficult to adjust the comprehensive development plan. ④The present formation pressure of the developed oil and gas reservoir is generally low, and the field lacks of gas source for gas injection, cyclic gas injection and single well huff-puff gas injection can not be properly implemented. ⑤Dynamic reserves are required to further verification. In November 2009,the pressure declines range from 50 to 60 percent in Kekeya Neogene XiHepu group gas condensate reservoir. The cumulative oil production of Kekeya gas field is 442.85 × 104t, cumulative gas production is 121.76 × 108m3, the degree of gas recovery is only 34%, the degree of oil recovery is only 16%.The characteristics of Kekeya gas condensate field development and comprehensive adjustment programs are carried out, and through research, the following understanding are achieved:(1) We develop further research for the property parameters of Kekeya gas condensate field, and establish the acoustic porosity calculation model of up oil group and down oil group and permeability and porosity calculation model, and thus definite the lower limit of reservoir properties.(2) The phase features changing of Kekeya gas condensate field is very complex. The phase diagram area of early well production component is relatively bigger, and the phase diagram area decrease with decreasing formation pressure.(3) X52、X72 and X42 is the main oil production layer system of Kekeya gas condensate field, and their formation pressures are generally low, that is in the range of 13 MPa to 15 MPa. We evaluate the production equitability of every layer through pressure drawdown strength index. From the longitudinal, the production of gas layer systems is slightly unbalanced, and the production of oil layer systems is basically balanced. According to the analysis of plane test well, the production is all balanced.(4) According to the statistical analysis of production decline rule of Kekeya gas condensate field, we find that the cumulative gas production per year accord with harmonic decline, the decline rate of per year is 12.82%, and the cumulative oil production per year accord with hyperbolic decline, the decline rate of per year is 15.59%. Overall, it belongs to medium decline. X3、X4、and X8 accord with harmonic decline. X41、X51 and X72 accord with hyperbolic decline. X42～X51 accord with exponential decline. From the month decline rule, X52 and X72 accord with harmonic decline, and X42～X51 accord with exponential decline.(5) We propose new method for calculating dynamic reserves and water influx of gas condensate reservoir with oil ring which applies production data. This method can calculate dynamic reserves and water influx of each single well and layer, as long as the pressure monitoring data and production dynamic data are provided.(6) We propose new method for calculating blowout quantity, and determine and evaluate the blowout quantity of every layer. The recommendation of condensate gas is 64.26×108m3 and that of oil is 58.12×104t.(7) Using the new method for calculating dynamic reserves and water influx of gas condensate reservoir with oil ring, we analyze the dynamic reserves and develop potential of Kekeya gas condensate field, and definite the single well develop potential of each layer.(8) We establish three-dimensional geological model of KeKeYa gas field, and research the remaining reserves of KeKeYa. On the basis of the above work, we proposed optimal adjustment plans for every layer system.