Integration of Mineralogy, Petrophysics, Geochemistry and Geomechanics to Evaluate Unconventional Shale Resources

Abstract

It is not entirely understood how related geological parameters vary during the thermal maturation and development of shale resources and controlling factors of shale productivity. Here, a detailed examination of mineralogy, geochemistry, petrophysics, and geomechanics-related data is conducted to explore the productivity of the Fox Creek, Alberta shale play. Experiments using X-Ray Diffraction, Tight Rock Analysis, Rock-Eval Pyrolysis, and Triaxial Compression are conducted to characterize the mineralogy, petrophysics, geochemistry, and geomechanics of the region under study. Multiple Linear Regression (MLR) is used to quantify the relationship between shale output productivity and reservoir input parameters. Using 300 core samples from 15 wells targeting the Duvernay shale, the key governing characteristics of shale potential were then examined. The Duvernay shale is dominated by quartz, clay, and calcite, according to X-Ray Diffraction measurements. Tight Rock Analysis indicates that the effective porosity of the Duvernay shale ranges from 1.56% to 6.11%, with an average value of 3.97 %, while the core permeability ranges from 0.25 to 345.5 nD, with an average value of 127.2nD. The total organic carbon (TOC) content ranged from 2.32 to 5.0 %, with an average of 3.86 %, according to Rock-Eval Pyrolysis testing. The majority of the Duvernay shale near the Fox Creek region (i.e., Fox Creek shale) was deposited in an oxygen-depleted maritime environment, whereas the Duvernay shale was in the gas generation window. The MLR technique determines the elements controlling shale productivity, including the production index, gas saturation, clay content, porosity, total organic carbon, brittleness index, and brittle mineral content as input parameters in decreasing order. Based on the MLR prediction model, the expected 12-month shale gas production per stage corresponds well with the actual value. This strategy can guide the future selection of horizontal well drilling sites and lead to the efficient and profitable development of shale resources.