Abstract
Increasing oil production from unconventional shale reservoirs is crucial to meet growing energy demands while achieving lower carbon emission than conventional crude oil. Enhanced oil recovery (EOR) has been proposed to improve hydrocarbon recovery rates through the injection of a fluid into the reservoir to facilitate residual oil release from the shale formation. However, economical and sustainable implementation of EOR requires advanced knowledge of fluid behavior in nano-sized pore spaces in shale. In this study, we utilize small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) as experimental probes to examine decane removal from a shale nano- to micro-porous matrix, utilizing methane as the injectant. The extent of decane saturation and recovery post-methane pressurization is quantified for clay-rich and carbonate-rich shale samples. A key finding is that extraction of decane by methane on depressurization is related to the methane-decane critical point. Furthermore, we found that although clay-rich shale had a much higher porosity of 5.6%, compared with 1.2% for carbonate-rich shale, decane was more easily removed from the carbonate-rich matrix, leading to similar hydrocarbon yields. These promising results demonstrate the ability of SANS and USANS to provide key insights into oil recovery from nano- to micron-sized pores in shale matrices. Combined with effects of various fractures on fluid behavior in shale, this experimental technique can be used to assess the viability of EOR injectants.
| Original language | English |
|---|---|
| Article number | 103950 |
| Journal | International Journal of Coal Geology |
| Volume | 253 |
| DOIs | |
| State | Published - Mar 15 2022 |
| Externally published | Yes |
Funding
This work was supported by the Chevron Technical Center , a division of Chevron USA, through a cooperative research and development agreement (CRADA) to the Los Alamos National Laboratory (LANL) (Project PIs: Michael Cheshire and Hongwu Xu). LANL is operated by Triad National Security , LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218NCA000001). The authors acknowledge the Center for Neutron Research (CNR) at National Institute of Standards and Technology for access to Small Angle Neutron Scattering (SANS). Access to Ultra-Small Angle Neutron Scattering (USANS) was provided by the Center for High Resolution Neutron Scattering , a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Di Wu acknowledges the institutional funds from the Gene and Linda Voiland School of Chemical Engineering and Bioengineering , and the fund of Alexandra Navrotsky Institute for Experimental Thermodynamics at Washington State University . This work was supported by the Chevron Technical Center, a division of Chevron USA, through a cooperative research and development agreement (CRADA) to the Los Alamos National Laboratory (LANL) (Project PIs: Michael Cheshire and Hongwu Xu). LANL is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218NCA000001). The authors acknowledge the Center for Neutron Research (CNR) at National Institute of Standards and Technology for access to Small Angle Neutron Scattering (SANS). Access to Ultra-Small Angle Neutron Scattering (USANS) was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Di Wu acknowledges the institutional funds from the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, and the fund of Alexandra Navrotsky Institute for Experimental Thermodynamics at Washington State University.
Keywords
- Enhanced oil recovery
- Nanoporosity
- Neutron scattering
- Shale
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