FRACTURING FLUID (GUAR POLYMER GEL) DEGRADATION STUDY BY USING OXIDATIVE AND ENZYME BREAKER

Hydraulic fracturing commonly refered to as fracking is a proven technology to enhance productivity and maximize recovery in oil and gas wells. Hydraulic fracturing method is ahnost the same as frac pack but differ in term of treatment purpose. Frac pack is aim for sand control while hydraulic fracturing is to stimulate the well. The fracturing fluid used in hydraulic fracturing or frac pack contain a chemical breakers to reduce the viscosity of the fluid intermingled with the proppant. Chemical breakers reduce viscosity of the guar, polymer by cleaving the polymer into small-molecular-weight fragments. The reduction of viscosity will facilitates the flowback of residual polymer providing rapid recovery of polymer from proppant pack. Ineffective breakers or misapplication of breakers can result in screenouts or flowback of viscous fluids both of which 9ail significantly decrease the well productivity. Breaker activity of low to medium temperature range oxidative and enzyme breaker systems was evaluated. ViCon NF an oxidative breaker (Halliburton product) and GBW 12-CD an enzyme breaker (BJ Services product) were used in this project with the main objective to study on the degradation pattern of fracturing fluid (guar polymer gel) as a function of time, temperature and breaker concentration itself. This paper provides a guideline of how to mix the fracturing fluid, the compositions of the fracturing fluid, and how to conduct the crosslink and break test. Crosslink test gave the optimum crosslinker concentration to produce good crosslink gel and the break test gave the characteristic of the gel during degradation process and also the break time. Besides relying on the laboratory experiment, information obtained from research on SPE and US Pattern papers were \)Sed to make a comparison study on oxidative and enzyme breakers properties. Degradation pattern observed from the break test showed that reduction in gel viscosity depends on time, temperature, and breaker concentration. Also, for enzyme breaker, increasing temperature does not mean more reduction in viscosity. Observation from experiment also revealed that small concentration of enzyme breakers provides rapid break compare to oxidative breakers