Influence of shear history at bottomhole temperature on fracturing-fluid efficiency

Journal Article · Mon May 01 04:00:00 EDT 1989 · SPE (Society of Petroleum Engineers) Product. Eng.; (United States)

DOI:https://doi.org/10.2118/14258-PA· OSTI ID:5869587

Harris, P C; Penny, G S

The effects of downhole environmental conditions on fracturing-fluid rheology and leakoff were evaluated in a flow loop at simulated fracture conditions. Linear and crosslinked gel fluids were subjected to shear rates of 50 to 100 seconds/sup -1/ past core for 4 hours at temperatures of 75 to 250/sup 0/F (24 to 121/sup 0/C). Nonlinear effects commonly observed with crosslinked gel fluids diminished as the fluid was sheared. Shearing for 30 minutes to 4 hours at 100 seconds/sup -1/ before a fluid-loss test was run resulted in leakoff following square-root-of-time behavior. Spurt loss increased for crosslinked gel fluids as the fluid degraded, whether by enzyme or oxidative mechanism. The leakoff coefficient decreased slightly with time under shearing conditions. Although the polymer was breaking, the absolute amount of polymer available for deposition did not change. The apparent viscosity of fluid remaining within the fracture was also investigated. During initial fluid leakoff, polymer was concentrated as a gel filter cake at the fracture face. Once an equilibrium filter-cake thickness was achieved, however, fluid loss to the formation resulted in an increase in the polymer concentration in the remaining fluid and hence an increase in apparent viscosity.

• Research Organization: 9502926; Stim-Lab, Inc. (US)
• OSTI ID: 5869587
• Journal Information: SPE (Society of Petroleum Engineers) Product. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Product. Eng.; (United States) Vol. 4:2; ISSN SPENE
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200 -- Petroleum-- Reserves
Geology
& Exploration
020300* -- Petroleum-- Drilling & Production
BOREHOLES
CAVITIES
CHEMICAL REACTIONS
COLLOIDS
DISPERSIONS
FLUIDS
FRACTURING FLUIDS
GELS
NONLINEAR PROBLEMS
OXIDATION
POLYMERS
RHEOLOGY
SHEAR
SIMULATION
SWEEP EFFICIENCY
TEMPERATURE EFFECTS
VISCOSITY