Low temperature degradation of galactomannans
This patent describes a method of fracturing a subterranean formation. It comprises: formulating a gellable fracturing fluid by blending together an aqueous fluid, a hydratable polymer, a suitable crosslinking agent for crosslinking the hydratable polymer to form a polymer gel, and an enzyme breaker; raising the pH of the fracturing fluid above about 9.0 to 10.5 whereby the enzyme breaker is inert; incorporating within the fracturing fluid of pH regulating substance which slowly hydrolyzes to produce a Bronsted acid, thereby dropping the pH of the fracturing fluid and activating the enzyme breaker with time to produce a controlled break of the polymer gel, the breaker being effective to degrade the polymer gel at temperatures below about 140-150 degrees F. within a time period less than about 24 hours.
- Assignee:
- BJ Services Co., Houston, TX (United States)
- Patent Number(s):
- A; US 5067566
- Application Number:
- PPN: US 7-640957
- OSTI ID:
- 5468797
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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023000 -- Petroleum-- Properties & Composition
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
COLLOIDS
DISPERSIONS
FLUIDS
FRACTURING FLUIDS
GELS
GEOLOGIC FORMATIONS
KINETICS
OIL WELLS
PH VALUE
POLYMERS
REACTION KINETICS
ROCK-FLUID INTERACTIONS
WELLS