一种新型二氧化碳驱特征曲线的建立与应用

A New Characteristic Curve of CO2 Flooding and Its Application

目前由于缺少完善的CO2驱特征曲线,矿场常利用水驱特征曲线评价CO2驱开发效果,导致评价结果与矿场实际情况差距较大。针对该问题,通过理论推导,研究气油比与累计产油量关系,在此基础上,推导累计产气量与累计产油量、气油比与累计产气量、产气率与累计产气量、产气率与采收率关系式,利用现场数据及调研结果建立适用于特低渗透油藏CO2驱特征曲线。CO2驱特征曲线可用修正系数对累计产气量与累计产油量关系进行修正。实例应用表明,胜利油田A区块及吉林油田B区块CO2驱最大采收率分别为17. 47%、19. 98%,以数值模拟预测结果为准,所建模型计算误差在5. 00%以内,与水驱特征曲线计算结果相比更加准确。该研究可为注气开发区块指标预测及效果评价提供理论基础。

Due to the lack of a perfect CO2 flooding characteristic curve,the field CO2 flooding performance is usually evaluated by the waterflooding characteristic curve,which results in a large deviation from the actual development performance. The relationship between gas-oil ratio and cumulative oil production was gained through theoretical derivation. A series of expressions were derived on this basis,including cumulative gas production and cumulative oil production,gas-oil ratio and cumulative gas production,gas production rate and cumulative gas production,gas production rate and recovery factor. Field and review data were used establish a CO2 flooding characteristic curve which is applicable to ultra-low permeability oil reservoir. The CO2 flooding characteristic curve could correct the relationship between cumulative gas production and cumulative oil production with correction coefficient. Field application indicate that the maximum recovery factors of Block A in Shengli Oilfield and Block B in Jilin Oilfield are 17. 47% and 19. 98% respectively. The relative error between this new model and numerical simulation is within 5. 00%,which is more accurate than that of waterflooding characteristic curve. This research could provide a theoretical basis for the development indicator prediction and performance evaluation in the CO2 flooding blocks.