利用毛管压力曲线计算砂岩渗透率的新方法

A new method for calculating sandstone permeability by using capillary pressure curves

(1.西安石油大学油气资源学院，陕西西安710065；2.中海油田服务股份有限公司测井解释中心，北京101149)

College of Petroleum Resources, Xi’an Petroleum University, Xi’an 710065, China

利用毛管压力曲线计算砂岩渗透率的方法关键在于Swanson参数(S_Hg/P_c)_max和Capillary-Parachor参数(S_Hg/P²_c)_max的确定，但传统的计算Swanson参数和Capillary-Parachor参数的方法存在人为因素影响较大和速度慢等问题。在对毛管压力曲线形态分析的基础上提出利用三次样条插值函数自动计算Swanson参数和Capillary-Parachor参数的新方法。将其与传统方法进行对比，验证了新方法的准确性。选取我国西部3个不同类型的油气田中渗透率介于0.002×10-3μm2~1150×10-3μm2的157块岩心，建立了Swanson参数和Capillary-Parachor参数与砂岩渗透率的关系模型。通过模型分析可知，利用新方法计算的Swanson参数和Capillary-Parachor参数与砂岩渗透率之间都具有很好的对应关系，Swanson参数与渗透率之间的对应关系比Capillary-Parachor参数与渗透率之间的对应关系更好，相关性更强。

The key technology of gaining sandstone permeability from capillary pressure curves is the determination of Swanson parameter and CapillaryParachor parameter. There exist many problems in conventional methods, including human factors affecting the result and slow velocity in calculation. Based on analyzing the shape of capillary pressure curves, a new method to automatically calculate Swanson parameter and CapillaryParachor parameter by using cubic spline interpolation function is proposed. The accuracy of the new method is verified by comparing it with the conventional methods. 157 core samples from three different fields in western China with the permeability ranging from 0.002×10-3μm2 to 1150×10-3μm2 are selected to establish the relationship model between Swanson parameter and CapillaryParachor parameter. After analyzing the models, the relationship between Swanson parameter and capillaryParachor parameter calculated by the new method well coincides with sandstone permeability. The correlation between Swanson parameter and sandstone permeability is better than that of CapillaryParachor parameter and sandstone permeability.