Alternatives for perforating a horizontal well to maximize well potential vary according to equipment availability and requirements. In a rigless operation in Algeria, the combination of orienting the perforations upwards and shooting multiple small intervals instead of the whole horizontal section while maintaining an accurate depth control was the biggest operational challenge of the project. The final design customized new technologies, including dynamic underbalance perforation, addressable switches, and the use of premium deep-penetrating shaped charges. The results were satisfactory, and the well, which was perforated in two stages, currently produces 2,000 m3/day crude oil from both the toe and heel sections.
Execution of the rigless, electric-line-equipped coiled tubing perforation in the horizontal well included aligning the charges to the upper side of the horizontal section to avoid salting and to prevent gun debris from falling down into the well, maintaining the debris inside the gun carrier. Several laminated sections out of the 600-m total horizontal section were selected, and accurate depth measurement and correlation were necessary to perforate only the cleanest 200 m.
This paper provides the operational sequence and discusses alternative conveyance methods available in the industry.