oa Integrated Log-core Calibrated Approach for Petrophysical and Geomechanical Characterization of Source-rocks

The prediction of mineralogy, TOC, grain density, porosity and gas saturation in organic rich shale is a challenging process that needs to rely on the integration of several measurement methodologies usually performed at different scale and by different disciplines. LECO analysis data can be used to measure the TOC values on core scale. Such values can drive the logs in estimating the TOC on a well scale. QEMSCAN measurements on core and cuttings provide accurate information about the shale composition. This information can be used, along with the TOC content, routine core data and the petrophysical deterministic analysis, to solve a probabilistic petrophysical model that allows characterizing the mineralogy and the organic content of the shale of interest along the whole well path. Once estimated the rock composition, the Brittleness Index can be estimated by assuming a multi-variable dependence between BI and the shale mineral composition. The BI calculated from the mineral composition can be further calibrated by using site specific rock cuttings and by correlating the BI values based on mineral components with the geomechanical response based on nano-indentation measurements. This methodology will be illustrated during the EAGE WS04 workshop with the Toarcian shale (COUY-1 well, Paris Basin, France).