ESTIMATION OF SHALE PETROPHYSICAL PROPERTIES; A STUDY FROM SEVIER SHALE, TENNESSEE

The shales of the Southern Appalachian Basin are major producers of natural gas, which promises to generate much of our nation’s natural gas supply in coming decades. As a result shale is becoming increasingly important in the petroleum industry and determination of their fundamental behavior as a part of natural gas extraction plan has recently become a vital focus in petroleum industries. Difficulty arises when shale behaves as heterogeneous and complex rock-mass. The purpose of this research was to study the fundamental petrophysical behavior of varied shale rock-mass. Sevier Shale is a complexly folded, thrust faulted and diverse rock-mass sequence in southern Appalachian Valley and Ridge Province. Thirty-six fresh rock samples were collected from outcrops, road cuts and shale quarries where the Sevier Shale is exposed. The pertinent petrophysical properties such as density, porosity, permeability, water content, and specific heat capacity were quantitatively measured in field and in laboratory based testing. The petrophysical properties were measured using standard ASTM (American Society for Testing and Materials) methods. Results indicated that properties like porosity, permeability and specific heat capacity varied significantly within samples, where as density and water content yielded steady values. Regression analysis was performed to evaluate possible correlations among the tested properties. Strong inverse relationship was evident between specific heat capacity and porosity. The overall research has helped towards better understanding of the petophysical behavior shale rock-mass which is important to consider for reservoir characterization, sedimentary basin analysis, exploration strategies, and potential borehole stability problem during gas exploration.