An Overview of the Subsea Equipment for the Osprey Project
Authors: Wilson R. 
Published: October 2008

1. ABSTRACT

Description

The paper includes details on:-General description of the Osprey Field. Development.Development of the Linear Block Manifold (LBM) Concept.The Production and Water Injection Linear Block Manifolds as cost-effective alternatives to large template piping manifolds.The special design features for ease of diver maintenance on the LBM's and Xmas Trees.General Conclusions.

Application

The Osprey Development utilises the cluster well and LBM concept for marginal field development.

The Osprey field is located in 520 feet of water, 7 Km. from the existing Dunlin 'A' platform in the northern North Sea.

Up to eight wells can produce to the LBM, where the flow is co-mingled and directed to the platform.

Results

By utilising standard subsea tree design and manufacturing technology, a one piece forged block manifold has been developed. It has suitable bores and outlets to facilitate connection of a number of cluster wells and transport pipelines.

Significance of Subject Matter

The cluster well and LBM concept provides a simple, low cost system, which can be applied to 'fast track' development of marginal fields.

The cluster type development overcomes many of the inherent problems of large templates or manifold structures without increasing costs.

2. INTRODUCTION

Osprey field in the next 5 is typical of the type of marginal development anticipated to occur U. K. Northern North Sea over the to 10 years.

The Osprey field is located in the North Sea in 520 feet of water, 7 Km. from the Dunlin 'A' platform in the Shell/Esso operated block 211/23a with the northern most tip extending into block 211/18a.

The reservoir is estimated to contain 60 million barrels of recoverable oil with little associated gas. Plateau gross fluid production is expected to reach 95,000 barrels per day with 85,000 barrels per day peak injection.

A variety of development options for this field were considered by Shell Expro. The final selection was the use of up to eight wells clustered around and producing to a Linear Block Manifold (LBM). The production flow from the wells will be co-mingled at the LBM and directed to the existing Dunlin 'A' platform to supplement its present production.

Previously, fabricated piping manifolds have been used to co-mingle flow from subsea wells prior to transport to the platform processing facilities.

The LBM concept uses Xmas Tree technology to produce a manifold from a single forging. The result is a reduction in size, cost, manufacture, test and installation times.

Previously, fabricated piping manifolds have been used to co-mingle flow from subsea wells prior to transport to the platform processing facilities.

The LBM concept uses Xmas Tree technology to produce a manifold from a single forging. The result is a reduction in size, cost, manufacture, test and installation times.

In this way first oil is achieved as soon as the LBM is installed and the pipelines connected. Should water injection not be required early in the field life, manufacture of the water injection block manifold can be delayed by a suitable period.