Arctic rig workover operations to perform reservoir control and remedial cement squeezes have been replaced by cost effective, state of the art coiled tubing technology at Prudhoe Bay. This non-rig workover (NRWO) approach is used to reduce high GOR and high watercut production without spotting a kill pill, pulling production tubing or drilling cement. The technique was implemented in the Prudhoe Bay Unit (PBU) Western Operating Area (WOA) during September, 1985, and includes 99 NRWO squeezes completed through December, 1987, by Standard Alaska Production Company (SAPC). This paper reviews the Production Operations and Engineering developments responsible for a successful NRWO program that has aided in extending plateau oil production and deferring decline point.

The Production Operations sections of the paper review field procedures and equipment used to perform low pressure squeeze techniques with low fluid loss cement slurries in an arctic environment. Discussion of field procedures include: cement slurry testing, pre-squeeze acid wash, sump cleanout, pressure control, wellbore liquid packing, Coiled Tubing Unit (CTU) depth control, pumping cement through coiled tubing and contaminating excess cement in the production liner to allow wellbore cleanout without drilling operations.

The Production Engineering sections of the paper review the candidate selection and evaluation process, general design considerations, program benefits and production results of WOA non-rig workover operations. As of year-end 1987, 57 gas shut-off (GSO), 23 water shut-off (WSO), 2 GS0/WS0 combination, 6 profile control, 2 plug & abandon and 9 pre-rig workover squeeze jobs have been completed. Program costs, incremental oil rate, additional recovery and repair longevity are also discussed.

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