Premium
Impact of chemical alteration on the poromechanical properties of carbonate rocks
Author(s) -
Bemer E.,
Nguyen M.T.,
Dautriat J.,
Adelinet M.,
Fleury M.,
Youssef S.
Publication year - 2016
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/1365-2478.12387
Subject(s) - petrophysics , poromechanics , geology , carbonate , geomechanics , outcrop , mineralogy , dissolution , carbonate rock , microscopic scale , igneous petrology , petrology , porosity , porous medium , engineering geology , geotechnical engineering , sedimentary rock , materials science , chemistry , geochemistry , tectonics , seismology , physics , volcanism , optics , metallurgy
The technical and economic success of a CO 2 geological storage project requires the preservation of the site injectivity and integrity properties over its lifetime. Unlike conventional hydrocarbon gas injection, CO 2 injection may imply geochemical reactions between acidified pore fluids and target reservoir formations, leading to modifications of their poromechanical properties. To date, the chemical effects on the host rock mechanical behaviour are not satisfactorily taken into account in site‐scale numerical models of CO 2 injection, mainly due to a lack of quantitative data. The present experimental work aims at characterizing the evolution of carbonate poromechanical properties induced by acid alteration. Unlike standard experimental approaches, the implemented alteration method induces a homogeneous dissolution pattern, which ensures reliable poromechanical measurements on altered samples. These well‐controlled alteration conditions allow a proper interpretation of the test results through the macroscopic continuous approach of poromechanics. Petrophysical, geomechanical, and petroacoustic properties of outcrop carbonate samples have been measured for different levels of alteration to mimic long‐term exposure to reactive brine. The obtained experimental data show clear trends of chemically induced mechanical weakening. Nuclear magnetic resonance measurements and microscanner imaging performed before and after alteration have provided complementary insights into the alteration effects at the microscopic scale.