多区不等厚横向非均质复合气藏试井分析模型及压力特征

Well test analytical model and pressure characteristics of multizone, non-isopachous and lateral heterogeneous composite gas reservoirs

针对长庆苏里格低渗气藏岩性发育不均匀、非均质性强的特点,建立了综合考虑表皮效应、井筒存储效应、气藏地层特性及地层厚度变化的多区不等厚横向非均质复合气藏试井解释模型,通过拉氏变换得出了无限大和封闭边界两种典型外边界条件下的气藏拟压力数值解,绘制了井底压降典型曲线,并对其压力动态特征进行了分析。利用该模型对苏里格气藏实际试井资料进行了解释,解释结果与实际生产动态情况较吻合。表明该模型对研究低渗透气藏储层特性有实用价值。

In view of the characteristics of uneven development of lithology and strong heterogeneity in Sulige low permeability gas reservoir of Changqing oilfield, a well test analytical model for muhizone, non-isopachous and lateral heterogeneous composite gas reservoirs is established, which comprehensively takes into consideration the skin effect, wellbore storage effect, formation characteristics of gas reservoirs and variation of formation thickness. Laplace transformation is used to achieve the numerical solutions of reservoir pseudopressure under two typical outer boundary conditions, infinity and closed boundary, to plot the typical curve of bottom-hole pressure drawdown, and to analyze the pressure behavior characteristics. This model has been used to interpret the real well test data of Sulige gas reservoir, and the interpretation results are in good accordance with the actual production performance, indicating that it is practical for studying the characteristics of low permeability gas reservoirs.