Abstract
Pierre shale is soft and difficult to frac. This is because of its high clay content. To increase the chances of a successful standard frac, we find that shale of this nature could be fractured by using a heat medium. Previous research has shown that a small increase in the temperature of frac fluid or water vapor creates a great number of micro fractures in shale, thus increasing the networks of interconnected gas and oil passageways in the shale mass [1,2,3]. Use of a heating medium to enhance the production of standard fracking requires documentation of Pierre shale thermodynamic properties. A set of experiments was designed to find the specific thermodynamic properties and associated strain properties of Pierre shale. Specimens of shale were prepared and coated with a film of random paint particles to allow us to perform digital image correlation and strain measurement. The results of data analysis showed that it is possible to create a model of frequency buildup behavior. The graph of strain data versus time shows how the heat waves pass through the shale with specific frequencies as it is exposed to the heat load. Additionally, we have calculated Poisson’s ratio and the resonance frequency of Pierre shale.
1. INTRODUCTION
Hydraulic fracturing is a well stimulation technique first pioneered in the 1940s. It is used after the drilling is completed to create fractures in a formation to stimulate hydrocarbon production. This increases the paths in which hydrocarbons can flow and be produced. Usually, high volumes of fracturing fluids are pumped into the well at a high pressure. These fluids are usually composed of 99% sand and water, with the other 1% containing additives such as gellant, friction reducers, acid, corrosion inhibitor, clay control chemicals, iron control chemicals, scale inhibitors, and biocide [4]. These additives vary from formation to formation.
