Increased production and lower costs in shallow gaswells are closely linked to developing and refining newcoiled-tubing drilling, completion, and productiontechniques. Innovations in coiled tubing have reducedthe costs of drilling and completing these wells andincreased their productivity and life cycles. Coiled-tubingfracturing is one such innovation. This has been used forsome time now, predominantly in North Americanshallow gas wells. In these wells, the cost advantagesassociated with working over the well in a live conditionwhile reducing job time are attractive.Coiled-tubing fracturing operations usually employstraddle-type tool configurations. However, with a typicalmaximum lubricator length of about 30 ft, straddleinterval lengths have been restricted, which increasesthe amount of resets required to effectively fractureindividual zones. This restriction also increases thepotential risk of communication above the assembly.This paper describes the development of aneconomical and reliable coiled-tubing fracturing systemthat allows selective fracturing of previously bypassedpay zones. This is now possible because the system canbe conveyed in a tandem configuration that works withincurrent lubricator restrictions, but is capable of settingrepeatedly as a retrievable bridge plug and treatingpacker combination. This allows longer zones to beprecisely isolated multiple times in a single trip in hole.This innovative technique can not only reduceintervention costs but also reduce the total time requiredto complete the operation. This paper will examineseveral case histories, with emphasis on pre-job planning, equipment selection, well site execution andpost-job results.
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