Sh_Pyroil for a Cost-Effective and Rapid Geochemical Pyrolysis Technique for Direct Hydrocarbon Saturation So Evaluation

Abstract

Abstract In carbonate and clastic reservoirs, determining the saturation levels based on log interpretation can be difficult. The traditional method of deriving saturation values using Archie's equation involves measuring "a," "m," and "n" factors on samples that are highly variable within a core. However, this approach assumes constant values for these factors throughout the entire reservoir section or a given rock type, leading to inaccurate hydrocarbon saturation measurements and impacting volume estimations. We propose an alternative solution that is real-time, cost-effective, and provides high confidence in identifying sweet spots for selecting perforation zones in a vertical well and plugging high water saturation zones in a horizontal well. Our solution involves a modified pyrolysis technique, which we refer to as "Sh_Pyroil." This technique enables the rapid (within 3 minutes) and low-cost measurement of direct hydrocarbon saturation. Sh_Pyroil is quantified in milligrams of hydrocarbons per gram of rock weight (mg HC/g rock) and can be easily converted into a percentage value for hydrocarbon saturation. To test the efficacy of this technique, we used modified pyrolysis on 90 core plugs extracted from dense and oil-bearing zones at one-foot intervals. The objective of our study was to compare the hydrocarbon saturation values obtained through thermally extracted core analysis using Sh_Pyroil with the saturation values derived from log interpretation (Archie's equation). This comparison allowed us to assess the applicability of Sh_Pyroil as a rapid, cost-effective, and high-confidence tool for directly measuring hydrocarbon saturation. Furthermore, the use of Sh_Pyroil can assist in making time-sensitive drilling and completion decisions, such as selecting optimal perforation zones and identifying high water saturation zones for plugging. Additionally, it can help in keeping horizontal wells within sweet spots and in estimating in-place hydrocarbon volumes in both conventional and unconventional reservoirs.