Customized Chemistry Design of Hydraulic Fracturing Fluids to Potentially Improve Hydrocarbon Recovery Factors

Abstract

Hydraulic fracturing fluid additives are designed to minimize formation damage and mobilize hydrocarbons to enhance oil recovery factors. Utilizing a multi-parametric selection methodology allows stimulation treatment additives to be optimized for performance factors on a well-specific basis. This paper discusses formation minerals and fluids from North American basins characterized to determine which chemical treatments are most effective at managing identified damage mechanisms and evaluate their impact based on production responses.

Reservoir specific materials—drilled cuttings and formation oils—were acquired from North American shale formations. The drilled cuttings were characterized using X-ray diffraction, cation exchange capacity (CEC), swelling sensitivity testing (SST), and mechanical stability turbidity (MST) testing to determine fluid sensitivity. Formation oils were characterized using API gravity, SARA (saturates, aromatics, resins, asphaltenes), and emulsion tendency. Next, the effects of clay stabilization and surfactant chemical additives were evaluated for efficacy using bench-top testing methods. Treatment performance for specific damage mechanism management was ranked and then compared to production data to determine enhanced oil recovery factors.

The research indicates that the average North American formation oil has a colloidal instability index of 2.6, and the average formation material has a CEC of 9. These classifications suggest that the average well would have low hydrocarbon mobility and exhibit fluid induced formation damage without chemical treatment. Formation materials were evaluated with cationic treatments: oligomer, low- and high-molecular weight polymer, as well as a brine to reveal the optimal product at effectively remediating clay swelling, fines generation and mechanical destabilization tendency varies based on the geochemical properties of the formation.. Hydrocarbons were evaluated with cationic, anionic, non-ionic, and microemulsion surfactants to reveal that all products above their CMC increased the mobility of hydrocarbons; however, the treatments that induced a weak emulsion, breaking between 1 and 5 minutes, had the most effect on mobilizing the hydrocarbons. Comparison of actual well production data reveals an increase in barrel of oil equivalent (BOE) over the life of the well for those wells stimulated with optimized chemical treatments, over offsets in the same region.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018