Nansen/Boomvang Field Development-Oil & Gas Export Systems
Authors: Dick Bill , Pearce Rob , Mann Jim 
Published: June 2014

This paper presents the management, execution, and design challenges and solutions to installing and commissioning the gas and oil export systems from the Spar production platforms for the Nansen and Boomvang field developments in the Gulf of Mexico. The project to design, manufacture, and install the gas and oil export systems and get the production to market was on a very aggressive schedule, compounded by the complexity of the overall work scope. This required a strong and coordinated project management and execution team using progressive design and implementation techniques to meet a fast track schedule and challenging design conditions. This paper discusses those issues and their solutions.

Introduction

The Boomvang and Nansen Fields developed by Kerr-McGee Oil & Gas Corporation, Ocean Energy, Inc. and Enterprise Oil, Gulf of Mexico is located in East Breaks area of the Gulf of Mexico. The development utilizes two "Spar" floating production systems, each capable of handling 40,000 BOPD and 200 MMSCFD of gas. The Nansen & Boomvang Fields are located approximately 115 miles south of Galveston, Texas in 3,675 and 3,450 feet of water depth, respectively. The Nansen & Boomvang Spars have a multilevel deck supporting well control equipment, first stage separation, and processing for the Spar-based wells and future satellite well installations. The gas and oil production is exported to markets on shore by Williams Field Services Company for processing, refining, and sales through installation and operation of the "Seahawk Gas Gathering System" and the "Banjo Oil Pipeline".

The Nansen and Boomvang Spars are permanently moored installations and can accommodate multiple production risers and surface trees, including the gas and oil export lines, connected by SCR's through the first J-Tubes/Truss Spars built in the world. Unique challenges were faced and conquered to provide the best functionally and cost effective methods of installation of the export pipelines and facilities for transporting the products to market in a timely and most marketable position. Preliminary contracts and LOI's were put together in the early phases of developing the project in order to secure costs, schedules and economics due to the complexity of the project and aggressiveness of the schedule, to a successful conclusion in all areas.

Description of Project

The system design provided for 400 MMSCFD of gas and 80,000 BOPD from the KMG Spars, split equally between the Spars. The natural gas is to be delivered through the new 115- mile "Seahawk Gas Gathering System" into the Central Texas Gas System (CTGS) about 30 miles offshore Freeport, Texas, where it is transported to markets on the Williams-Transco system as well as four other lesser capacity pipeline connections on the CTGS system. The oil is to be transported through the new 56-mile "Banjo Oil Pipeline" to the Exxon Hoops line already existing in the area that delivers oil to the pipeline terminals in Jones Creek and Texas City. The oil and gas pipelines were designed to handle the above mentioned volumes at maximum design operating conditions required by the Spars.