Quantitative Mineralogical and Petrophysical Analysis of Cuttings

For the characterization of most reservoir sections, cuttings are the only available “real time” and continuous option to acquire rock samples for a direct petrographic and petrophysical analysis. However the use of modern PDC drill bits only provides nearly powdered cuttings with rock fragments in the mm range, that are not suitable for any conventional petrophysical lab measurements. After the successful test and introduction of Digital Core Analysis (DCA) combined with Pore Network Modeling (PNM) technologies based on the acquisition of 3D Micro-CT tomograms at different scales for conventional core samples , we initiated a special study to test this new technology for a “Tight Gas” appraisal well to identify and quantify the mineralogical composition and topological pore structure to generate “synthetic” petrophysical properties on irregular shaped Cuttings in the mm range. A case study will be presented of a recent deep “Tight Gas” appraisal well in the Middle East, where significant sections with high gas readings and high shale and potential high TOC content could be identified from mud logs and log evaluations . Only cuttings were available to quantify and “calibrate” the mineralogical composition and potential storage and flow capacity of these different rock types . A new technology approach was applied for the quantitative mineralogical and petrophysical analysis of Cuttings with the successful application of BSEM/EDX and Digital Core Analysis (DCA) technology based on 3D Micro-CT images for a tight /shale gas “unconventional” reservoir . This new DCA/PNM technology enables a very quick characterization of reservoir rock properties even in cases where “conventional” core material and “conventional core analysis” (RCA/SCAL) are not available or possible for the reconciliation of log derived formation evaluation results.