Abstract

Over the past decade, multiphase pumping technology has been increasingly becoming an acceptable alternative for conventional technologies. Indeed in many oil producing areas of the world, multiphase pumping is considered a state of the art and best practice. Multiphase pumping can offer numerous advantages in terms of HSE, operability, capital and operating costs as well as improved recovery.

Operators in the gulf countries have been slow to introduce multiphase pumping. The number of operating field installations in the gulf to date is limited. This is due to a number of reasons.

This paper presents an overview of multiphase pumping technology. The paper reviews the current multiphase installations in the gulf and addresses the reasons behind the limited applications. Future potential applications of this technology in the region are also discussed.

1. Introduction

As demand for energy continues to grow, the importance of increasing recovery from existing reservoirs and developing marginal fields have become essential. Producers are looking at new technologies such as multiphase pumping to extend reservoir life and improve recovery. The first oil field testing of multiphase pump prototypes took place in the early nineties. Since then, there are now several hundred multiphase pump installations throughout the world. These installations are onshore, offshore on topside and subsea.

Multiphase pumping offers numerous advantages over conventional oil production techniques. These advantages include the following:

  • Multiphase pumping eliminates equipment such as separators, compressors, pumps, flares and allows the centralization of processing facilities. This is shown schematically in figures 1 and 2.

  • One export pipeline instead of two export pipelines.

  • Multiphase pumping enhances HSE aspects. This is due to eliminating flares and minimizing potential for spills because of the simpler facilities. Also, both foot prints and facilities weight are reduced.

  • Multiphase pumping can increase the reservoir recovery factor by extending the producing life of mature fields. This is done by lowering the flowing pressure at which the well otherwise would not be produced (figure 3).

  • Multiphase pumps can improve flow assurance by mitigating some potential problems. For example, multiphase pumps breaks-up terrain or riser-induced slugs and prevents separator flooding and liquid-carry over. Also in some cases, reducing wellhead flowing pressure below hydrate formation pressure will eliminate the need for methanol injection.

  • Multiphase pumping is particularly attractive for remote areas or for tie-in of remote wells.

  • Due to the above reasons, multiphase pumps can offer advantages in terms of capital and operating costs.

2. Classification of Multiphase Pumps

Historically, multiphase pumps (MPP) were categorized either as twin screw pumps or helicoaxial pumps. Today, there are many types of multiphase pumps using diverse technologies and a more comprehensive classification is required. Scott [1] classifies multiphase pumps into positive displacement and rotodynamic types. This paper extends Scott's classification further (figure 4).

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