Revolutionizing Offshore Production by In-Line Separation Technology
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 135492, ’Revolutionizing Offshore Production by InLine Separation Technology,’ by R. Fantoft, SPE, R. Akdim, SPE, R. Mikkelsen, T. Abdalla, SPE, R. Westra, and E. de Haas, SPE, FMC CDS Separation Systems, originally prepared for the 2010 SPE Annual Technical Conference and Exhibition, Florence, Italy, 19-22 September. The paper has not been peer reviewed.

During the last decade, in-line separation technology has been introduced successfully to several applications. In-line separation is separation in pipe segments instead of within large vessels. In particular, separation by use of cyclonic forces has been important. In-line technologies for separation of gas and liquid, oil and water, sand and liquid, and multiphase streams have been developed and already are used extensively in retrofit applications to increase the performance and capacity of existing offshore production systems.

Introduction

Compact separation solutions have received substantial attention for offshore process systems over many years. The capacity, size, and robustness of separation equipment are key parameters for the value of an offshore production system. Conventional separation equipment consists of large vessels and contributes heavily to the size and weight of the overall processing system. When first installed, the separator vessels can be modified only to a limited degree to handle variations in operating conditions. It is a common challenge to maintain or increase the processing capacity after the field has been put in operation because of the following:

As reservoir pressure decreases as the field matures, increased production may be achieved by decreasing the inlet pressure, which requires changes to the processing system, including modifications of the separation equipment.

There is increased water production with need for increased water-handling capacity to maintain high oil- and gas-production rates.

There may be a switch from primary oil to primary gas production, giving new system requirements.

With tiebacks of surrounding fields to existing infrastructure, modifications of the existing production plant may be required for optimal production from the combined new and old fields.

It is a common problem that there are limited opportunities to modify existing processing plants because the separator vessels have a defined volume. Normally, it is not feasible to add processing capacity by installing new separator vessels on an existing offshore platform.

However, in-line separation equipment offers new degrees of freedom to modify the processing plants. In-line separation equipment can be put in series and in parallel to already-installed separators to improve capacity and performance.

There also are great economic incentives to enable more-compact separation for new-build platforms. Today, the cost and weight of the platform is heavily dependent on the large volumes required for conventional separation equipment. Substantial savings can be achieved by relying on in-line separation equipment for new-build processes.