Biopolymer solution viscosity stabilization-polymer degradation and antioxidant use
Dilute solutions of polymers used to provide mobility control for EOR often lose viscosity, especially at higher temperatures. This loss of viscosity with time brings into question the feasibility of using polymers as mobility control agents. A literature study of the many possible reaction mechanisms indicated that oxidation/reduction (redox) reactions involving free radicals probably caused polymer degradation and concomitant viscosity loss. A preliminary search for antioxidants known to retard free-radical reactions located several types and positive synergistic formulations that significantly retarded biopolymer solution viscosity loss during accelerated tests at high temperature. The most effective type formulation found contained (1) a radical transfer agent; (2) a sacrificial, easily oxidizable alcohol; (3) a compatible oxygen scavenger; and (4) sufficient brine concentration. Samples prepared with this technology have not lost viscosity after 1-year storage at 207/sup 0/F (97/sup 0/C). A high-surface-area effect (so-called ''wall effect''), known to retard radical propagation, was also found to operate in the presence of sandpacks; this should be beneficial in porous media. The variables and beneficial antioxidant formulations identified in this study allow tentative conclusions and recommendations regarding biopolymer mixing and handling procedures prior to injection.
- Research Organization:
- Shell Development Co.
- OSTI ID:
- 7151654
- Journal Information:
- SPEJ, Soc. Pet. Eng. J.; (United States), Journal Name: SPEJ, Soc. Pet. Eng. J.; (United States) Vol. 23:6; ISSN SSPJD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Elevated temperature testing of mobility control reagents
Development of correlations to predict biopolymer mobility in porous media
Related Subjects
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030900 -- Natural Gas-- Artificial Stimulation
Plowshare-- (-1989)
ADDITIVES
ALCOHOLS
ANTIOXIDANTS
BRINES
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DISPLACEMENT FLUIDS
ENHANCED RECOVERY
FLUIDS
HYDROXY COMPOUNDS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
ORGANIC COMPOUNDS
OXIDATION
POLYMERS
RADICALS
RECOVERY
REDOX REACTIONS
STABILITY
SYNTHESIS
TESTING
THERMAL DEGRADATION
THERMAL TESTING
VISCOSITY