Chemical stability limits of water-soluble polymers used in oil recovery processes

Journal Article · Mon Feb 01 04:00:00 EST 1988 · SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States)

DOI:https://doi.org/10.2118/13585-PA· OSTI ID:5287759

Ryles, R G

This work describes long-term thermal stability limits of water-soluble polymers under anaerobic conditions. Polymers investigated included polyacrylamide, xanthan, scleroglucan, cellulose sulfate, and a heteropolysaccharide of unknown structure. The primary mechanism of polyacrylamide degradation was found to be amide group hydrolysis. Interaction between hydrolyzed polyacrylamide and divalent metal ions present in solution caused significant losses in solution viscosity, and phase separation ultimately occurred in extreme conditions of high degrees of hydrolysis or high concentrations of divalent ions. The rate of hydrolysis was found to depend mostly on temperature. At 50/sup 0/C (122/sup 0/F), the rate was quite slow and polyacrylamide solutions were stable for many months, even in the presence of high concentrations of divalent ions. At 60 to 70/sup 0/C (140 to 158/sup 0/F), the rate of hydrolysis was moderate and the rate of viscosity loss depended on the precise temperature and divalent ion concentration. At 90/sup 0/C (194/sup 0/F), hydrolysis was rapid and polyacrylamide solutions were stable to precipitation only when the divalent ion concentration was less than about 200 ppm. When the divalent ion concentration was zero, solution viscosity increased because of a further expansion of the polyelectrolyte coil. The stability of xanthan was determined primarily by temperature and was independent of divalent ions. Although performance varies from xanthan to xanthan, the useful limit was generally found to be <70/sup 0/C (<158/sup 0/F). Viscosity retention was also found to be extremely shear-rate dependent. Other naturally occurring polymers exhibited variable performance. In alkaline brines, polyacrylamides were stable up to 90/sup 0/C (194/sup 0/F) for long periods of time, whereas xanthan was degraded at >50/sup 0/C (>122/sup 0/F).al

• Research Organization: American Cynamid Co. (US)
• OSTI ID: 5287759
• Journal Information: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States) Vol. 3:1; ISSN SREEE
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling &amp; Production
AMIDES
CARBOHYDRATES
CELLULOSE
CHEMICAL COMPOSITION
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
DECOMPOSITION
DISPLACEMENT FLUIDS
ENERGY SOURCES
ENHANCED RECOVERY
ESTERS
FLUID INJECTION
FLUIDS
FOSSIL FUELS
FUELS
GLUTIN
HYDROLYSIS
LYSIS
MEDIUM TEMPERATURE
OIL WELLS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PETROLEUM
PHASE STUDIES
POLYACRYLATES
POLYMERS
POLYSACCHARIDES
POLYVINYLS
PROTEINS
RECOVERY
SACCHARIDES
SCLEROPROTEINS
SOLVOLYSIS
STABILITY
STIMULATION
SULFATES
SULFUR COMPOUNDS
WATERFLOODING
WELL STIMULATION
WELLS
XANTHUM GUM