Abstract

This paper describes the key planning and operational experiences gained during the perforation and completion phase of the world record step-out extended reach well at the Wytch Farm oilfield in Dorset, England. The paper presents an overview of how the M- 11 well was successfully completed and describes how a combination of existing technology and new technology has been applied to achieve Wytch Farm's most prolific producer to date.

Well 1M-11SPy (M-11) holds the world record for the highest horizontal departure, 10114m, at any vertical depth, and a record departure: to true vertical depth (TVD) ratio of 6.24. The Wytch Farm extended reach wells are completed with cemented, perforated liners and electrical submersible pumps (ESPs).

A new technique for perforating the well was developed to maximise inflow efficiency. This technique enables underbalance perforating without any subsequent requirement for a well kill. The impact of these improvements on completion efficiency is discussed, along with the associated operational issues.

The large departure required the ESP to be set at 8625m, another world record, with the 1000 HP motor requiring a new 7kV cable system and a 1500 kVA variable speed controller (VSC) at surface. This paper describes the background of VSC selection and the physical testing of the complete ESP/cable/VSC system that was conducted prior to installation to ensure that sufficient torque could be generated at the ESP for a range of start-up and operating conditions, and to configure the new type of VSC used for optimal system performance.

The paper reports experience gained, and reviews lessons learned.

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