芳48CO2驱油先导试验区水气交替参数优化

Parameter optimization of water alternating gas of Fang 48 CO_2 flooding pilot area

以芳48断块CO2驱油先导试验区为研究对象,对其数据进行历史拟合后,从2010年3月开始设计5 a的水气交替方案进行模拟研究。按照正交试验的方法对水气交替方案进行设计,从而在相对较少方案的基础上对水气强度比、段塞大小、注入强度、水气段塞比等参数进行优选,并对影响水气交替效果的因素进行排序。结果表明:对于芳48断块的水气交替,对其采出程度影响最大的是水气强度比,其次依次为日注水量,周期注入量和水气段塞比;据累积采出程度优选出的最佳方案参数为周期注入0.005VHCP(VHCP为烃孔隙体积)、日注水量7 m3、水气注入强度比1∶2、水气地下段塞体积比1∶2,与直观分析所得最优参数取值基本一致。该方案2015年的采出程度为18.73%,比衰竭开发提高了5%以上。

Selecting Fang 48 fault block CO2 flooding pilot area as the research object, the history matching was carried out, water alternating gas （WAG） scheme of five years was designed and simulated which began in March, 2010. Different WAG schemes were designed based on the orthogonal test method, then the parameters such as water gas intensity ratio, slug size, injection rate and water gas slug ratio were optimized reliably by numerical simulation based on relatively few schemes, and the influencing factors were sorted according to intuitive analysis. The results show that for Fang 48 fault block, the factors affect the ratio of total oil produced to OOIP, in descending order of water gas intensity ratio, daily water injection volume, injection volume per cycle and water gas slug ratio. The parameters of the optimum scheme are as follows： injection rate is 0. 005 hydrocarbon pore volume per cycle, daily water injection volume is 7 m^3 , water gas injection intensity ratio is 1 ： 2, and water gas slug size ratio underground is 1 ： 2. The optimum results agree well with the intuitive analysis results. The ra-tio of total oil produced to OOIP of this scheme in 2015 is 18.73%, which is 5% higher than that of depletion.