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Role of Well Operations and Multiphase Geomechanics in Controlling Fault Stability During CO 2 Storage and Enhanced Oil Recovery
Author(s) -
Zhao Xiaoxi,
Jha Birendra
Publication year - 2019
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2019jb017298
Subject(s) - geomechanics , overpressure , enhanced oil recovery , caprock , petroleum engineering , geology , pore water pressure , water injection (oil production) , oil field , overburden , oil sands , shear (geology) , geotechnical engineering , shearing (physics) , petroleum reservoir , petrology , materials science , physics , asphalt , composite material , thermodynamics
Abstract CO 2 injection in active oil fields is a technology proposed for industrializing carbon storage operations. However, monitoring CO 2 migration, oil recovery, and mechanical deformation within caprock and on faults is a challenging problem in large‐scale storage‐enhanced oil recovery operations due to intersecting faults, multiphase flow effects, and wells with complex production‐injection schedule. We develop and demonstrate a methodology based on our coupled modeling framework to monitor the movement of CO 2 , hydrocarbons and water, and the associated evolution in mechanical stability of faults during CO 2 storage‐enhanced oil recovery in the Farnsworth Unit oil field in Texas, United States. The methodology honors geological, geophysical, and production‐injection data acquired in the field over six decades. Differential depletion from hydraulically isolated fault compartments followed by water and CO 2 injection‐induced overpressure causes volumetric contraction and expansion of the reservoir, and changes in the total and effective stresses in the overburden‐reservoir‐underburden complex. CO 2 migrates upward to accumulate near top of the geologic structure, and water migrates downward to pressurize the faults. Three‐dimensional changes in the pressure and stress fields in the system lead to changes in the shear and effective normal tractions on three major faults compartmentalizing the field. Evolution in fault tractions is used to compute the evolution in the Coulomb failure function of the faults to quantify induced‐slip tendency under production and injection. We explain the spatial heterogeneity and time variability of Coulomb failure function in terms of well location heterogeneity and well rate variability.