Sakhalin II Conversion of the Molikpaq for Drilling/Production and Deeper Water
Authors: Mitchell R.A. , York S.D. 
Published: October 2008

To achieve early production from the Piltun-Astokhskoye License Area offshore Sakhalin Island, Sakhalin Energy secured the Beaufort Sea ice-class drilling vessel "Molikpaq" in mid-1997 with a plan in place for its conversion to a drilling/production/accommodation platform. This paper discusses the activities and challenges associated with that conversion as carried out with the joint cooperation and support of several specialized Russian Federation institutes and experts.

Areas of emphasis include engineering considerations, vessel condition, construction and certification. Sakhalin Energy's engineering considerations included critical environmental issues such as wave, wind, ice and earthquake data. Construction activities included expanding the existing eight-well drilling platform to 32 well conductors. Other additions included a process module, wellhead truss, wave deflector upgrades, general refurbishment, earthquake stiffening, pipe barn modifications and HVAC considerations for the accommodation and services modules. A critical aspect of the conversion was the mating and weld-out of the Russian-built spacer substructure with the Molikpaq in May 1998. Total structure weight is now 51,600 metric tons.

The Molikpaq conversion broadened the Sakhalin II team's knowledge of other existing arctic drilling rigs in the Beaufort Sea. This information would be applicable to any readying of such vessels for a new environment. The problemsolving effort on this phase also would facilitate future preparation of data base cost analysis for any new arctic development scheme. In terms of constructability, Sakhalin II team members learned how to incorporate a fast-track project into Far East shipyards' highly efficient operations. The project team altered the sequence of its engineering process for an improved delivery of detailed drawings.

A Beaufort Sea drilling vessel initially put into operation in 1984 has become operable as an ice-resistant arctic caisson with production facilities in a new arctic region. The structure includes appropriate and economic improvements for a safe operation.

Introduction/Design Basis for Early Production System

Driven by a need for an economic solution for the successful development of the Sakhalin II energy asset, the Sakahlin Energy shareholders selected an existing Beaufort Sea arctic caisson facility as their best option for project go-ahead in mid-1997. The "Molikpaq," an ice-class drilling vessel built in 1984, offered the project owners a two-fold solution: a viable approach for keeping development costs down by avoiding a new-build structure and a vehicle for getting revenue onstream as quickly as possible with early production from the Piltun-Astokhskoye License Area. As a result, the shareholders, Russia and the industry are looking forward to first oil in July 1999. A new-build facility would have postponed this historic event by one-to-two years.

To meet the environmental needs and production requirements for Russia's first offshore development, the ABS-classed Molikpaq would undergo a significant conversion process to become a drilling/ production/accommodation platform. This paper discusses the activities and challenges associated with that conversion. Areas of emphasis include engineering considerations, vessel condition, construction, and certification. Critical issues for the region's hostile environment include wave, wind, ice and earthquake data. Severe storms and significant seismic activity characterize the area's arctic climate.