Mathew Samuel

Wettability Alteration for Water Block Prevention in High Temperature Gas Wells

A chemical system alters the formation wettability to intermediate gas-wet conditions, thereby decreasing capillary forces and enhancing clean-up of trapped water at low drawdown pressures.

Determination of the Effect of Formation Water on Fracture Fluid Cleanup Through Field Testing in the East Texas Cotton Valley

A field study in east Texas showed that formation water production influences polymer recovery from hydraulic fractures. This study was conducted on 10 wells located in the Cotton Valley Taylor formation. A typical fracture stimulation design included between 9,000 to 14,000 bbl of zirconium crosslinked guar gel. Detailed chemical analysis of flowback samples was used to identify the effect of formation water on polymer recovery. Polymer and chloride concentrations were measured. Water produced during flowback averaged 52 ± 5% of the fluid pumped on the jobs, while polymer recovery during flowback averaged 35 ± 6% of the amount pumped. Polymer concentration in the flowback fluid from all the wells declined over time, as chloride concentration increased. This is attributed to the production of formation water. Flowback rate has a minimal effect on polymer recovery from these wells. The results of this study are compared with those previously obtained from another low permeability formation, specifically the Codell formation in Colorado. Flowback analysis is an important tool to determine how specific reservoir conditions influence fracture cleanup.