Utilization of Sidewall Plugs for Enhancing Rock Characterization

Complete rock property characterization based on whole core acquisition helps generate reservoir specific correlations for play characterization. Conventional whole core ensures superior quality representative plugs from the specific formations of interest. Sidewall core acquisition has gained popularity as a lower cost alternative due to lower operational costs. The data generated from the sidewall core plugs can be used to enhance the generated reservoir specific correlations, which have higher accuracy than global empirical correlations. The primary uncertainties for rock mechanics characterization using sidewall core are the accuracy of the data obtained and maximizing the information obtained from the very limited amount of available material. The additional consideration, of meeting the dimensional requirements of ASTM/ISRM testing standards, increases the complexity and difficulty of managing the available material. This paper proposes a test program and testing protocol that maximizes the information generated from sidewall core plugs. This is achieved by sub-coring to obtain plugs with reduced dimensions while adhering to the established ASTM/ISRM standards. The effect of reduced sample size on test results is investigated by comparing it with data from standard size plugs. The potential testing suite design enables characterization of the Biot's coefficient, the fracture toughness and Brazilian tensile strength from plugs sub-cored from a sidewall core.