Three Major Conveyance Methods to Lower the Perforating Guns To Well

Perforation is a process creating holes in casing (or liner) to connect the reservoir with the well-bore and allow hydrocarbons to flow into the well. Perforating guns with charges are used to punch holes in well casing. In the open-hole environment, guns are lowered into the well using electric-line (E-line) or tubing. Guns are run to the desired depth, after which a perforation job starts. A number of different gun systems are available for selection, depending on subsurface and perforation requirements.

There are 3 major conveyance methods to lower the perforating guns to the well, as below:

1) Through-Casing Perforating is used prior to the well completion in order to accommodate larger diameter guns. The size of guns is normally between 3”and 5” in diameter and is run using a wire-line. This perforating method is used to provide greater penetration due to larger size of guns. As well, so called "tractors" may also be deployed to allow guns to be run into deviated wells. One of the major restrictions of using this method is well inclination and pressure requirements, e.g. when under-balance is required.

2) Tubing Conveyed Perforating (TCP) uses guns that are attached to the tubing (drill pipe, coiled tubing or production tubing). The major advantages of this method is that it allows leaving production tubing in the well, after perforating is completed (running together with a completion string), long and widely spaced intervals, and application in highly deviated and horizontal wells. Major drawback of TCP guns is until the completion is retrieved (full work-over) guns cannot be retrieved. Hence, the reliability of TCP guns is of utmost importance, as any misfire will result in poor perforating job and significantly affect future production profiles.

3) Trough-tubing Perforating Guns are guns, small in size, used in completed wells and run through production tubing. The system is low cost and allows under-balanced perforation, however provides limited penetration.

Gun systems fall into two distinctive categories:

1) Exposed (Capsule) guns and

2) Hollow carrier guns. All guns are triggered electrically at the surface and come in a range of sizes to suite the well-bore requirements.

Above information is from http://www.scmdaleel.com/category/e-logging-amp-perforation/19

Any interests on perforating gun and accessories please contact Vigor info@vigordrilling.com