This paper presents case histories showing that operators drilling in eastern states have increased oil and gas production by reducing the amount of guar polymer used to stimulate a well. The fluid system used in the 80 to 140°F applications in the region is a 20- to 25-lbm/Mgal guar with a buffered borate crosslinker that provides an instant crosslink. The wells being treated as described are shallow, and rapid complexation is needed to ensure proppant transport through the perforations.

Laboratory test results are also presented. Rheology and sand transport for the optimized fluid system are compared to similar properties of conventional borate-crosslinked fluids. In general, fluid properties of the low-guar polymer compare to properties of conventional borate-crosslinked fluids containing polymer concentrations 5 to 15 lbm/Mgal greater. Viscosity and fluid-efficiency values of the low-guar system (25 lbm/Mgal) compare to a 35-lbm/Mgal conventional borate-crosslinked fluid. Because reservoir cleanup after fracturing is an important component of production, production increases seen in these wells are mainly attributed to the lower gel loading used.

Keywords:
conventional borate 0, viscosity, gel loading increase well production, concentration, mgal conventional borate 0, proppant, conventional borate fluid, hydraulic fracturing, enzyme breaker, mgal lg 0
Subjects:
Drilling Fluids and Materials, Hydraulic Fracturing, Well & Reservoir Surveillance and Monitoring, Fracturing materials (fluids, proppant)
Copyright 1998, Society of Petroleum Engineers
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