小断块油藏单井CO2吞吐强化采油注气时机及周期注入量优选

低渗小断块油藏控制单元井间连通性差，边界封闭，地层能量有限，开采中地层能量下降快，难以采用早期注水等方式大规模开采。利用CO2吞吐强化采油对此类油藏可能是一种有效的方法。为此，首先对油井目前流体进行相态分析，并对油藏流体进行CO2膨胀实验，然后将注气前后地层流体的物性进行对比，确定CO2增产机理。再在此基础上建立单井CO2吞吐的数值模拟模型，并对注气前生产历史进行拟合，用拟合好的模型对CO2吞吐强化采油过程中注气时机和周期注入量等进行敏感性分析，从而得出一些对小断块单元油藏单井CO2吞吐强化采油开采机理的深入认识，为油井CO2吞吐强化采油可行性的工艺方案设计提供了技术依据。

Optimization of single well CO2 injection occasion and cyclic injection rate in small fault block reservoir

It is difficult for complicated small fault block,low permeability reservoir to be recovered by commercial-scale waterflooding in early stage because of poor inter-well communication,boundary seal,and limited reservoir energy.CO2 injection may be an effective method to such reservoirs.Therefore,present reservoir fluids are analyzed,CO2 expansion test is conducted,and fluid properties are compared before and after gas injection to determine stimulation mechanism.Numerical model of single well CO2 stimulation is established,production history before gas injection is matched,and sensitivity analysis is carried out for gas injection occasion and cyclic injection rate by using the matched model, thereby derived a deep understanding to exploitation mechanism of small fault block reservoir unit recovering by single well CO2 injection and provided technical support to enhanced recovery by CO2 injection.