66 D2. Energy Geology

Tuesday, 27 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

IMPACT OF MATURATION PROCESSES ON ORGANIC MATTER IN SHALES: IMPLICATION FOR GEOLOGIC CARBON SEQUESTRATION

Paper number: 66-18
Program: Technical Sessions
Time: 5:10 PM – 5:15 PM

Authors

Abstract

The Middle Bakken has low porosity and permeability, which makes Bakken shales an attractive candidate for geologic CO2 sequestration. Previous studies have shown that unconventional reservoirs, such as Bakken shales, provides viable potential for geologic CO2 storage after depletion through primary production. In this study, we experimentally assess how the maturation-induced modified properties of organic matter will impact geologic CO2 storage in shales.

We utilized artificially matured Bakken shale samples kept in the oven at 340°C with increasing thermal maturity (Tmax419-445°C). Firstly, we analyzed the shale samples to evaluate the altered geochemical properties. Secondly, we conducted scanning electron microscopy to characterize alterations in the texture and distribution of organic matter. Subsequently, we utilized a reflected light microscope for advanced microstructural characterization of the morphological modifications. Lastly, we showed the geologic CO2 storage implication of the modified geochemical and microstructural properties due to impact of maturation process on organic matter.

Our analysis from the geochemical results show alterations in the total organic carbon content (TOC) and hydrogen index, and this alteration continue with increasing thermal maturity. The microstructural analysis also shows reduction in the pore structure of the shale rock. Consequently, the alterations in TOC and microstructure of the Bakken Shales due to the impact of the maturation process, improves its suitability as a caprock in conventional trapping scenarios, or as a CO2 storage medium itself after depletion.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-353832

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.