The proper selection of fracturing fluid is one of the most critical elements in Fracture Completion Services design. To select the proper fluid, concerns such as fluid-loss control, fracture conductivity, formation damage, and proppant transport must be considered.Extensive testing should be conducted to promote better understanding of fracturing-fluid behavior in treatments of high-permeability formations. The fluids are evaluated for fluid-loss properties, regained permeability (formation damage), and fracture conductivity. The results from these tests would help in making the best fluid selection for a given well. The results from various formation-damage tests and fracture-conductivity tests around the world haveshown hydroxyethyl cellulose (HEC) to be the most applicable linear gel for Fracture treatments. Borate-crosslinked hydroxypropyl guar (HPG) gels are found to be the most effective crosslinkedfluid system for Fracture Completion Services. The use of either a linear gel or a crosslinked gel is dependent on permeability of formation, reservoir fluid and reservoir pressure of candidate well.
Formation damage and fracture conductivity studies have shown that breakers should be in solution when fracturing high-permeability formations so that the entire crosslinked gel volume that leaks off into the formation can be effectively broken. Fracture conductivity can be enhanced if an encapsulated breaker is placed in the proppant pack .
Available Fluid Systems
As many as 50 different fluids are present to solve various needs within the oil- and gas-well stimulation and completion markets. The major types of fluids that remain at the backbone of the industry are as follows: