In early 2007 the operator was looking at options to drill additional gas wells. A hydraulic workover unit (HWU) had been used to previously sidetrack a number of wells offshore Dubai and a decision was taken to investigate this option further.

The goal was to drill the same well profile as a jack-up did on a previous campaign but at lower costs.

The work scope for the HWU campaign would include the retrieval of the existing completion, setting a whipstock, milling through two casing strings, drilling 8-1/2″ build-up section into the top of the reservoir, lining off with a 7″ liner, horizontally drilling the reservoir section in 6-1/8″ hole and finally completing with a 5-1/2″ completion. Due to time constraints all planning including contracting was performed in a two months window prior spud.

The operator selected three mother wells on a platform connected to the main field facilities, which included accommodation and logistical support.

With the reservoir being at around 3,300 feet TVD, a total of 4,285 feet were drilled in the three sidetrack wells. A regional first achieved is the drilling of 1,500 ft of 8-1/2″ and running of a 7″ liner with a HWU.

This paper will describe the planning, challenges, limitations, learnings from the campaign and the resulting innovations for future HWU projects, which includes the concept of ‘using self-elevating-workover-platform’ or ‘lift boat’ and purpose built, minimized footprint tank farms for standalone production platforms.

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