Title: Probing oil recovery in shale nanopores with small-angle and ultra-small-angle neutron scattering

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.more » Combined with effects of various fractures on fluid behavior in shale, this experimental technique can be used to assess the viability of EOR injectants.« less

Authors:

Neil, Chelsea W.  ^[1];

• Search DOE PAGES for author "Neil, Chelsea W."
• Search DOE PAGES for ORCID "0000-0002-7679-157X"

Hjelm, Rex P. ^[2]; Hawley, Marilyn E. ^[1]; Watkins, Erik B.  ^[1];

• Search DOE PAGES for author "Watkins, Erik B."
• Search DOE PAGES for ORCID "0000-0001-8573-9629"

Cockreham, Cody ^[3]; Wu, Di ^[4]; Mao, Yimin ^[5]; Cheshire, Michael ^[6]; Burger, Jon ^[6]; Fischer, Timothy B. ^[6]; Stokes, M. Rebecca ^[7]; Xu, Hongwu  ^[1]

• Search DOE PAGES for author "Xu, Hongwu"
• Search DOE PAGES for ORCID "0000-0002-0793-6923"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National Security Education Center; New Mexico Consortium, Los Alamos, NM (United States)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Washington State Univ., Pullman, WA (United States); Washington State Univ., Pullman, WA (United States). Alexandra Navrotsky Inst. for Experimental Thermodynamics
4. Washington State Univ., Pullman, WA (United States); Washington State Univ., Pullman, WA (United States). Alexandra Navrotsky Inst. for Experimental Thermodynamics
5. Univ. of Maryland, College Park, MD (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research
6. Chevron Technology Center, Houston, TX (United States)
7. Chevron Technology Center, Houston, TX (United States); US Geological Survey, Reston, VA (United States). Energy and Minerals Science Center

Publication Date:

Sat Feb 12 00:00:00 EST 2022

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)

OSTI Identifier:

1862810

Report Number(s):

LA-UR-21-26696
Journal ID: ISSN 0166-5162

Grant/Contract Number:  

89233218CNA000001; DMR-1508249

Resource Type:

Accepted Manuscript

Journal Name:

International Journal of Coal Geology

Additional Journal Information:

Journal Volume: 253; Journal ID: ISSN 0166-5162

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

04 OIL SHALES AND TAR SANDS; Earth Sciences; shale; enhanced oil recovery; neutron scattering; nanoporosity