ABSTRACT
Determining the treatment or job schedule is the last step in a stimulation design. Treatment scheduling consists of selecting a pad volume, a slurry volume to follow the pad, and a proppant addition schedule specifying the proppant concentrations to be used. The treatment schedule and the required proppant concentrations needed to create a desired žnal fracture length and conductivity depend primarily on the type of µuid used. For cross-linked gels, very little proppant settling occurs, and each stage must be designed to leave the desired proppant concentration in the fracture when the treatment ends. For low-viscosity, “linear,” or “slickwater” µuids, proppant tends to settle out of the µuid and form a proppant bank near the wellbore. Because of this, there are two general approaches to treatment scheduling: (1) perfect support µuids and (2) banking µuids. In higher permeability cases where it is desirable to have higher conductivity, a greater žnal propped fracture width than allowed by “normal” treatment design procedures is needed. In these cases, a third style of treatment termed a “tip screen-out” (TSO) procedure can be used to increase the žnal propped fracture width and conductivity.
