Multistage fracturing using plug-and-perf systems

摘要

The plug-and-perf system creates multiple hydraulic frac-tures in a horizontal well completed with a cemented casing/ liner. This system combines elements of two common fracturing techniques: limited entry and segmented fracturing using bridge plugs. Commercially these systems are offered and supported by several suppliers. System description. Fracturing operations begin from the toe of the well and proceed toward the heel, Fig. 1. Each pumping stage is used for fracturing multiple clusters of perforations designed based on the limited-entry technique. The number of clusters is based on the injection rate, with details discussed later. The sequence of operational steps consists of setting the plug in the desired location within the horizontal well, perfo-rating the clusters and pumping the treatment according to the design. After all pumping stages are complete, all the plugs are milled out, and the well is cleaned and put on production. Depending on requirements, there are a variety of plug types used in these completions, but they are all drillable/millable and usually made of special composite material.