Advanced Cuttings Analysis Improves Reservoir Characterisation and Reduces Operating Times in Shale Gas Drilling Project

Abstract

Abstract Significant improvements in shale gas reservoir characterization have been recently obtained by means of detailed geochemical and mineralogical analysis on cuttings and cores directly at wellsite using the combined application of different technologies. These technologies include: X-ray diffractometry for mineralogy, X-ray fluorescence for rock chemical (elemental) composition, TOC analysis for Total Organic Carbon measurement and Pyrolysis for source rock characterization (Hydrogen Index, free oil content, Petroleum Potential & Maturity Index). The analyses, normally carried out in specialized laboratories, have been performed while drilling into a field unit. Dedicated procedures were also defined in order to improve the quality of the cuttings and to optimize the analyses timing to obtain near real time responses. The first field application has been carried out within an exploratory campaign for a shale gas drilling project. The rig site analyses provided in near real time complete geochemical/mineralogical log of the reservoir section. Wellsite analyses have been afterwards validated by laboratories analyses repeated on the same samples, confirming the reliability and accuracy of the rig site measurements. The Advanced Real-Time Cutting Analysis provided a strong support to the drilling operations (selection of the coring point, identification of sweet spot, etc.) resulting in significant time and cost savings in the well target phase and allowed for a reliable quick Formation Evaluation by using the organic matter and mineralogy data to calibrate the wireline logs response. The acquired data were also used to update the geochemical model utilized in the Petroleum System Model performed during the pre-drilling phase for a better understanding of the reservoir during the ongoing exploratory campaign.