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Title: CO 2 utilization and storage in shale gas reservoirs: Experimental results and economic impacts

Natural gas is considered a cleaner and lower-emission fuel than coal, and its high abundance from advanced drilling techniques has positioned natural gas as a major alternative energy source for the U.S. However, each ton of CO 2 emitted from any type of fossil fuel combustion will continue to increase global atmospheric concentrations. One unique approach to reducing anthropogenic CO 2 emissions involves coupling CO 2 based enhanced gas recovery (EGR) operations in depleted shale gas reservoirs with long-term CO 2 storage operations. In this paper, we report unique findings about the interactions between important shale minerals and sorbing gases (CH 4 and CO 2) and associated economic consequences. Where enhanced condensation of CO 2 followed by desorption on clay surface is observed under supercritical conditions, a linear sorption profile emerges for CH 4. Volumetric changes to montmorillonites occur during exposure to CO 2. Theory-based simulations identify interactions with interlayer cations as energetically favorable for CO 2 intercalation. Thus, experimental evidence suggests CH 4 does not occupy the interlayer and has only the propensity for surface adsorption. Mixed CH 4:CO 2 gas systems, where CH 4 concentrations prevail, indicate preferential CO 2 sorption as determined by in situ infrared spectroscopymore » and X-ray diffraction techniques. Collectively, these laboratory studies combined with a cost-based economic analysis provide a basis for identifying favorable CO 2-EOR opportunities in previously fractured shale gas reservoirs approaching final stages of primary gas production. Moreover, utilization of site-specific laboratory measurements in reservoir simulators provides insight into optimum injection strategies for maximizing CH 4/CO 2 exchange rates to obtain peak natural gas production.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Univ. of Wyoming, Laramie, WY (United States)
Publication Date:
Report Number(s):
PNNL-SA-105772
Journal ID: ISSN 1876-6102; AA7020000
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Energy Procedia
Additional Journal Information:
Journal Volume: 63; Journal ID: ISSN 1876-6102
Publisher:
Elsevier
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 54 ENVIRONMENTAL SCIENCES; carbon sequestration; clay minerals; wet supercritical carbon dioxide
OSTI Identifier:
1223423