The Current State of Development of the VASPS Subsea Separation and Pumping System
Authors: Entress J.H. , Pridden D.L. , Baker A.C. 
Published: October 2008

VASPS (Vertical Annular Separation and Pumping System) is an integrated subsea separation and pumping system which can be installed within a 30 inch conductor in a dummy well. The system is assembled from essentially standard components and is installed and maintained using established drilling technology.

VASPS is being developed in a three stage programme. The first stage consists of a series of large scale model tests, mathematical modeling of the flows within the unit and a series of engineering studies. This stage of the work is now drawing to a close, and has confirmed the viability of the VASPS concept. Some of the results of this work are described and elaborated upon in this paper.

Stages II and III of the development programme involve full scale prototype tests on operating oil fields, and these are due to commence shortly. It is hoped to make VASPS available commercially by the end of 1993.

Introduction

Subsea separation and pumping is regarded as one of the main candidate technologies for the production of remote marginal oil reservoirs. VASPS (Vertical Annular Separation and Pumping System) is an unusual implementation of this production technology in that it does not rely on the transfer of conventional topsides processing equipment to a subsea environment. VASPS utilises essentially standard well componentry in a novel manner enabling a high capacity (up to 30,000 bbl/day) separation and pumping system to be installed within a 30 inch conductor in a dummy well. Installation, maintenance and repair are effected using established drilling technology. VASPS thus offers a number of advantages over more conventional subsea separation and pumping systems.

VASPS is being developed in a three stage programme:Stage I consists of large scale model tests on the novel separator configuration, mathematical modelling of the complex flowfields within the unit, and a series of mechanical and systems engineering design studies. The aim is to prove concept viability and position the project for subsequent prototype tests.Stage II involves the construction and testing of a full scale surface prototype on a producing oil field. This serves to prove the unit on live well stream fluids.Stage III involves the deployment of a subsea prototype for testing on a field development project. This will prove the efficacy of the subsea installation, maintenance and repair techniques as well as providing invaluable operational experience in a subsea environment.

Stage I of the programme commenced in early 1990 and is currently drawing to a close. Stages II and III are scheduled such that surface prototype testing will take place late 1991/early 1992 and deployment of the subsea prototype should follow some twelve months later. It is hoped to make VASPS commercially available by the end of 1993.

The Stage I experimental results and engineering studies indicate that the VASPS concept is indeed viable. Accordingly, this paper endeavors to highlight the main items arising from the experimental work to date and touches on how these combine to influence the final subsea separator configuration.