注气驱油藏新型气驱特征曲线推导及应用

针对传统气驱特征曲线未能有效描述地层中实际渗流的流体（注入气）和被驱替原油的关系，在分析油藏注气开发驱替过程基础上，分别描述了混相驱和非混相驱油气渗流特征。基于稳定渗流理论，推导出了地层中实际渗流流体（注入气）和被驱替原油的关系式，即累积注气量累积产油半对数关系，命名为新型气驱特征曲线，分析了该曲线的适用条件。应用实例，研究了注采井网和驱替机理变化对气驱曲线形态特征的影响。在已知注气量的条件下，利用该曲线可实现长期及阶段产量预测，且在注气开发较早阶段便可应用。

Derivation and Practice of the New Gas Flooding Characteristic Curve of Reservoir with Gas Injection Flooding

Because the conventional gas flooding characteristic curve fails to effectively describe actual seepage fluid (injected gas) in stratum and displaced crude oil, displacement process of gas injection development is analyzed and oil and gas seepage characteristics of miscible flooding and immiscible flooding are represented, respectively. Based on the steady seepage theory, the relational expression of the actual seepage fluid (injected gas) in stratum and displaced crude oil is derived, which is a semi-logarithmic function of cumulative gas injection volume and cumulative oil output; this is termed the new gas flooding characteristic curve, and its applicable conditions are analyzed. Relevant examples are applied to study the effect of changes to the injection production pattern and displacement mechanism on the characteristics of gas flooding curve. Under the condition of a given volume of gas injection, this curve can be used to accomplish long-term and stage-yield prediction, and can be applied at the initial stages of gas injection development.