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The coupled effect of salt precipitation and fines mobilization on CO 2 injectivity in sandstone
Author(s) -
SokamaNeuyam Yen Adams,
Ursin Jann Rune
Publication year - 2018
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1817
Subject(s) - dissolution , brine , supercritical fluid , precipitation , saturation (graph theory) , permeability (electromagnetism) , geology , salinity , mineralogy , chemical engineering , chemistry , membrane , combinatorics , meteorology , engineering , biochemistry , physics , oceanography , mathematics , organic chemistry
Appreciable CO 2 injectivity is required to inject large volumes of CO 2 through a minimum number of wells. In situ geochemical CO 2 ‐brine‐rock reactions may dissolve sandstone rock minerals, and consequently release fine particles into the pore fluid. If the fine particles (‘fines’) are mobilized during CO 2 injection, well injectivity could be severely impaired. The transport of fines under CO 2 injection conditions involves the complex multiphase flow of dry supercritical CO 2 , saline formation brine, and fine particles. While transported fines could plug narrow pore channels, the saline pore water could be vaporized by supercritical CO 2 to precipitate solid salt into the pores. To understand the impact of mineral dissolution on CO 2 injectivity, it is important to consider the coupled effect of fine particle mobilization and salt precipitation. We conducted core‐flood experiments and theoretical modelling to investigate the coupled effect of the fines mobilization and salt precipitation on CO 2 injectivity. We found that salt precipitation could increase CO 2 injectivity impairment induced by the fines mobilization. The deposited salt reduces the flow area, making the pores more susceptible to particle entrapment. Injectivity impairment increased with decreasing initial rock permeability and increasing saturating brine salinity. Irreducible brine saturation and pore size distribution were identified as parameters that strongly determine the contribution of salt precipitation during the transport of fines. Injectivity impairment was also slightly higher when the rock was first exposed to salt precipitation, before the entrapment of fines. The current findings highlight the complexity and uniqueness of fines transportation under CO 2 injection conditions and the impact of mineral dissolution on CO 2 injectivity. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.