Abstract

This paper describes the summer 1998 offshore installation of the Sakhalin Energy Vityaz Production Complex. The paper details the various facilities installed, the marine equipment used, logistical obstacles and some of the unexpected developments during the installation. Key elements of the Vityaz Production Complex include the modified Molikpaq platform, a 2-km long by 324-mm diameter pipeline for oil export, the SALM base structure/pipeline end manifold, and SALM buoy for FSO tanker mooring.

Van Oord ACZ of the Netherlands was the main contractor for the installation, which included five very different activities: towing with multiple tugs, dredging, rock dumping, pipeline laying and traditional derrick barge activities of heavy lifting/diving/pile driving. Foundex, Ltd of Canada performed explosive densification of the approximately 350,000 metric tons of sand loaded into the core of the Molikpaq.

Each of the following activities covered here includes valuable lessons for future frontier projects in remote areas:

  • Molikpaq tow from Korea to Sakhalin Island

  • Ballasting and set down of the Molikpaq

  • Dredging activities

  • Scour protection activities

  • SALM base and buoy installation

  • Pipeline installation

  • Core fill explosive densification

  • Logistics of working in remote parts of Russia

The contractors relied on personnel from more than 20 countries to bring together the wide variety of skills required for this landmark project. The project management team required interpersonal skills to negotiate between the various cultures, languages and work practices in order to safely carry out the installation activities.

The installation of the Vityaz Production Complex has progressed smoothly and has helped to build confidence within the Russian Federation that the Sakhalin II production sharing agreement will bring long-term economic benefits to the country and region.

Introduction

The Vityaz Production Complex offshore Sakhalin Island (Russian Far East) centers around the permanent drilling and production unit Molikpaq and serves the Phase I development of the Piltun-Astokhskoye (PA) Field.

The Molikpaq (a modified existing steel Mobile Arctic Caisson) is an octagonal bottom founded steel annular structure over the Astokh feature of the PA Field. The facility will have an oil production and gas handling capacity of 4.5 million tonnes/year (90,000 B/D) and 0.74 billion m3/year (72 mmscf/D), respectively. The oil produced will be transferred by pipeline to a SALM Buoy, which forms the mooring point for a Floating Storage and Off loading tanker (FSO) for off loading to buyer tankers. The Phase I development scenario is shown in Figure 1.

The Molikpaq was constructed in 1983/1984 as a Mobile Arctic Caisson, offshore drilling unit, with a classification rating of ABS ice class 1AA. The Molikpaq has operated in this capacity in the Beaufort Sea (Canadian Arctic) as a drilling facility only. For its new application offshore Sakhalin a Process Module and other facilities were added. In addition, it was mated with a 15 meter high substructure, the so-called "Spacer", during a nine months refurbishment programme at the Daewoo Heavy Industries Shipyard at Okpo, South Korea. The Molikpaq was then towed from Korea to the installation location offshore Sakhalin Island. It was placed on an engineered foundation pad formed by dumping of dredged sand into an excavation which removed inferior seabed material. After set-down of the platform, the centre core of the Molikpaq was hydraulically filled with dredged sand. The foundation pad soil improvement and core filling was requi

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