A New Model between Dynamic and Static Elastic Parameters of Shale Based on Experimental Studies

Abstract

During the exploration and development of shale gas resources, elastic parameters provide crucial geomechanical information for shale gas extraction and hydraulic fracturing projects. Static elastic parameters are usually adopted in rock mechanics analyses and hydraulic fracturing designs and are generally obtained from experimental tests using core samples collected from the subsurface. However, experimental core data could be discontinuous despite the high costs. Dynamic methods, including well logging and seismic survey, are applied in practice. Given the difference between static and dynamic elastic parameters, dynamic elastic parameters gained from those aforementioned dynamic methods need to be converted to static elastic parameters. Currently, static and dynamic elastic parameter test data are often directly used in converting dynamic elastic parameters to static elastic parameters without consideration of the influence of rock mineral composition on the difference between elastic and dynamic elastic properties. Consequently, the conversion results cannot fully reflect reservoir geomechanical conditions. In this research, the rock mineral composition is analyzed, and the effects of various mineral components on static and dynamic elastic parameters of shale are discussed. A new conversion model is established by taking into account the rock mineral composition. The new model is capable of providing improved conversion results and thus can be applied in shale gas extraction and hydraulic fracturing projects at the target reservoir. Therefore, this research has both theoretical and practical impacts.