DOI: 10.1016/j.epsl.2018.07.013
Scopus记录号: 2-s2.0-85050501406
论文题名: Effect of CO2–brine–rock interaction on fracture mechanical properties of CO2 reservoirs and seals
作者: Major J.R. ; Eichhubl P. ; Dewers T.A. ; Olson J.E.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 499 起始页码: 37
结束页码: 47
语种: 英语
英文关键词: CO2 sequestration
; Crystal Geyser
; diagenesis
; fracture
; fracture mechanics
; natural CO2 analog
Scopus关键词: Calcite
; Carbon dioxide
; Cements
; Chromium compounds
; Degrees of freedom (mechanics)
; Dissolution
; Flow of fluids
; Fracture
; Fracture mechanics
; Germanium compounds
; Geysers
; Hematite
; Mechanical properties
; Network security
; Precipitation (chemical)
; Sandstone
; Shale
; Water injection
; Chemical interactions
; CO2 sequestration
; diagenesis
; Fracture propagation
; Fracture-mechanical properties
; Mechanical parameters
; natural CO2 analog
; Opening mode fracture
; Fracture toughness
; brine
; carbon sequestration
; diagenesis
; fluid injection
; fracture mechanics
; hydrocarbon reservoir
; sandstone
; sealing
; water-rock interaction
; Green River
; United States
; Utah
英文摘要: The effect of CO2–water–rock interactions on fracture mechanical properties of reservoir and seal rocks due to injection of CO2 in the subsurface may impact long-term (102–104 yr) storage security. At the Crystal Geyser and Salt Wash field sites near Green River, Utah, sandstone of the Salt Wash Member of the Morrison Formation and Mancos Shale have undergone chemical alteration associated with flow of CO2-bearing water under natural conditions over geologic time scales of 103–105 yrs. To quantify the effects of these diagenetic changes on rock fracture mechanical properties we conducted opening-mode fracture mechanics tests using the double torsion method on a suite of CO2-altered and unaltered siliciclastic samples. We show that dissolution of hematite and carbonate cement in Entrada Sandstone by CO2-rich brine lowers fracture toughness by nearly 40% relative to adjacent, unaltered samples from the same unit. In contrast, precipitation of calcite pore cement in a sandstone of the Salt Wash Member of the Morrison Formation, attributed to CO2 degassing during upward fluid flow along the Little Grand Wash Fault, results in a 100–700% increase in fracture toughness. Similarly, precipitation of carbonate mineral cements and replacement of matrix measurably strengthens Mancos Shale, considered a regional top seal. Subcritical fracture growth index (SCI) which quantifies reaction-assisted subcritical fracture propagation is also affected by CO2-related alteration. Based on previous numerical simulations of fracture network growth with varying fracture mechanical parameters, we find that the measured variations in fracture mechanical properties qualitatively match observed differences in opening-mode fracture distributions along the fault, with short, non-connected fractures in CO2-bleached rock, long, throughgoing fractures in calcite-cemented shale, and short, closely spaced, interconnected fracture networks in highly altered rock directly adjacent to fault conduits. Our fracture mechanics tests demonstrate that fracture mechanical properties of reservoir and seal rock can change as a result of chemical CO2–brine–rock interaction. These chemical interactions may favor or inhibit subcritical fracture growth processes and thus reservoir and seal flow properties. In regions of CO2-related mineral dissolution, subcritical fracture growth may reduce seal integrity over time scales beyond those of active injection and reservoir monitoring, thus negatively affecting seal integrity over the expected design lifetime of a CO2 reservoir. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109702
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Bureau of Economic Geology, The Jackson School of Geosciences, The University of Texas at AustinTX 78713-8924, United States; Geomechanics Department, Sandia National Laboratories, Albuquerque, NM 87185, United States; Department of Petroleum and Geosystems Engineering, The University of Texas at AustinTX 78712, United States
Recommended Citation:
Major J.R.,Eichhubl P.,Dewers T.A.,et al. Effect of CO2–brine–rock interaction on fracture mechanical properties of CO2 reservoirs and seals[J]. Earth and Planetary Science Letters,2018-01-01,499