An experimental study of calcium carbonate consolidation via polyacrylamide for carbonate reservoir strengthening.
File(s)
Author(s)
Lew, Jin Hau
Type
Thesis
Abstract
This thesis investigates the interaction of polyacrylamide (PAM) with calcium carbonate (CaCO3) for weak carbonate reservoir rock strengthening. The study was conducted in three steps. The first step involved examining PAM chemistry (molecular weight, proportion of charged monomers, functional group) on CaCO3 consolidation. Molecular weight study showed that while higher molecular weight PAM exhibited higher adsorption onto CaCO3, the storage modulus (G’) and unconfined compressive stress (UCS) of CaCO3 consolidated by different molecular weight PAM is very similar. A study on proportion of charged monomer showed that PAM with smaller percentage of charged monomer adsorbed less onto CaCO3, but the G’ and UCS of CaCO3 consolidated by lower charge PAM is higher due to bridging interaction. A functional group study revealed that sulfonated polyacrylamide (SPAM) exhibited lower adsorption and consolidation of CaCO3 when compared to hydrolysed polyacrylamide (HPAM), due to its bulky sulfonated side group hindering adsorption. Second step involved studying the effect of salinity, temperature and pH on CaCO3 consolidation by PAM. Salt ions from brine screened the polymer’s charge monomer, causing polymer chain coiling. G’ of CaCO3 consolidated by PAM prepared in brine revealed that either higher polymer dosages were required to achieve similar consolidation, or reduction in peak G’. Elevated temperatures caused a reduction in G’ for CaCO3 consolidated by HPAM, although to a lesser extent for SPAM. Altering the pH from pH 9.5 (polymer pH) to pH 8.3 (reservoir pH) did not significantly affects HPAM consolidation performance. The final step involved crosslinking PAM with silica nanoparticles (SiONP) to preserve the usability of PAM in harsh reservoir environments. The crosslinked PAM samples demonstrated significant improvement in consolidating CaCO3, evident by the larger G' values compared to no-crosslinking, despite the crosslinked PAM samples being exposed to high temperatures and brine conditions typical of reservoir environments.
Version
Open Access
Date Issued
2024-07-19
Date Awarded
01/12/2024
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Matar, Omar K.
Luckham, Paul F.
Müller, Erich A.
Publisher Department
Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)