Frac-and-Pack Completion

Abstract

A relatively short, highly conductive fracture created in a reservoir of moderate to high permeability will breach near-wellbore damage, reduce the drawdown and near-wellbore flow velocity and stresses, and increase effective wellbore radius. Fracturing treatments of this type have two stages: fracture created, terminated by tip-screenout, and fracture inflation and packing. Such a two-stage treatment is the basis of a number of well-completion methods, collectively known as frac-and-pack. This technique has been successfully applied, with a range of fracture sizes, to stimulate wells in various reservoirs worldwide.This chapter discusses the criteria for selecting wells to be frac-and-packed. It is shown how a systematic study of the inflow performance can be used to assess the potential of frac-and-packed wells, to identify the controlling factors, and to optimize design parameters. It is also shown that fracture conductivity is often the key to successful treatment. This conductivity depends largely on proppant size; formation permeability damage around the created fracture has less effect. Appropriate allowance needs to be made for flow restrictions caused by the presence of the perforations, partial penetration, and non-Darcy effects.The full potential of this completion method can be achieved only if the design is tailored to the individual well. This demands high-quality input data, which can be obtained only from a calibration test.