Influence of Fracture Treatment Parameters on Hydraulic Fracturing Optimization in Unconventional Formations

Hydraulic fracturing is the most effective reservoir-stimulation techniques in the petroleum and geothermal industries. It is most suitable for wells in low and moderate permeability reservoirs that do not provide commercial production rates. Due to technical and economical limitations of hydraulic fracturing operations in unconventional reservoirs, geothermal systems, and block cave mining worldwide, an optimized hydraulic fracturing design is critical for successful stimulation operation. Fractures created require proppant to keep it open after injection has stopped. Furthermore, proppant transport and placement, proppant and frac-fluid compatibility, and optimum spacing are some of the challenges inhibiting successful hydraulic fracturing operations. Proppant transport depends on the particle size, proppant density, and the fluid viscosity. In this paper, we investigate the effects of proppant densities, fluid viscosities, and injection rates on hydraulic fracturing parameters. To accomplish our objectives, we created the geological layering in the zone of interest using specified formation properties in a 3-D numerical simulator. Appropriate fluid and proppant were selected. Results obtained show that injection rate of 13 bpm yielded the longest fracture, propped and effective prop length for both proppants. While the high-density proppant gave the longer fracture length, the low-density proppant produced the longest fracture length. In the rate sensitivity on dimensionless fracture conductivity (C_FD), high density proppants yield lower C_FD, while lower density proppants yield higher C_FD. The methodology is applicable to geothermal wells that require fracturing to create effective communication between the reservoir and the wellbore. Hence, we suggest application of the methods and results in geothermal wells, for proactive decision making in well stimulation treatments.