PRODUCTION TECHNOLOGY Multiphase pumping - Where to now?

Multiphase Pumping Systems's MP 10 gas engine driven self-contained multiphase pump for Oil India Ltd is the latest to be installed on the surface.

The following presentation details the technical and commercial challenges facing multiphase pumping, and involves a panel of industry viewpoints. The presentation has been compiled by Peter Lovie and Ken Barker. The comments expressed are individual and do not necessarily represent company positions.

The first effective multiphase pumps (MPP) for oilfield production use were demonstrated more than 20 years ago. Since 1970, equipment manufacturers and oil companies have spent a great deal of money on the development of various subsea multiphase pumping tech nologies. However, despite dozens of encouraging field and laboratory tests, only a few units have so far been purchased and employed by the oil industry in operations.

Many oil companies still see the utilization of multiphase pumps in subsea operations as risky. Oil prices remain low and uncertain, and budgets are tight. Competitive options for the development of subsea field production facilities may be available. And, although these may have some disadvantages compared with MPP systems, they use traditional practices and proven technology.

In contrast, MPP systems currently lack significant operating experience particularly in subsea applications. However, their ability to handle, long-term, a wide range of production conditions unique to a field (conditions which may possibly change significantly as production rates fall) is improving rapidly as a result of the extensive field trials currently in progress. Nevertheless, this factor has been a major disincentive for most oil companies to employ MPP equipment. As a result, there has been only limited opportunities for the manufacturers to accumulate the required field operating experience.

How to resolve this closed loop predicament? It is unlikely to happen without innovative new approaches involving both providers and users. There are many key issues involved here. Comments from some of the organizations most closely involved with the development and use of multiphase pumps in subsea environ ments illustrate the diversity of opinion on the subject.

Current situation

• Today, major US, European, and Brazilian oil companies are performing studies on the use of MPPs in deep water.
• Field trials of subsea separation processes were carried out in 1970 (BP - Zakum) and in 1987 (Hamilton brothers - Argyle), but none are currently in progress. In contrast, two major evaluations of MPPs in subsea service are underway. One is a commercial installation for Shell (Draugen - Norwegian North Sea) and the other a extended field trial for Agip (Prezioso - Off shore Sicily).
• Pump manufacturers have MPP units on surface field trials in many onshore locations as well as offshore on platforms. Tests are being conducted both indepen dently and also jointly through joint industry project- sponsored initia tives. Howev er, with some notable exceptions, the sponsoring oil compa nies and the pump manufacturers are reluctant to discuss details and results.
• Interest in MPPs remains high, as indicated by the number of papers on the subject to be presented during the technical session of the 1995 Offshore Technology Conference in Houston this year.
• Several of the pump manufacturers are introducing new multiphase booster units that offer significant operating advantages over previous models.
• The accelerating trend towards marginal field development is encouraging a more flexible attitude among operators to the employment of new methods and hardware.
• Turn-key development approaches are also becoming more common off shore. In these, specialized contractors with the appropriate technical and coordinating skills, take greater responsibility for the selection and detailing of systems and their implementation.
• MPP units are already commercially available from several manufacturers.
• There is no universal MPP unit. Different equipment packages address differ ent operating conditions. Most will require some customizing to meet the unique requirements of specific fields and applications.

RAY GOODRIDGE
Multiphase Systems

Ray Goodridge is managing director of Multiphase Systems Plc., of Bristol, England. He has been the driving force behind his company's development of multiphase pumps since 1969.

In 1968, we designed and built for a major oil company a multiphase pump unit capable of handling 80% gas by volume at the pump inlet. In subsequent tests this unit amply proved its abilities and the equipment was supplied to the overseas field location in 1970 and commissioned the following year.

During the period 1970-1980, we improved the pump design to handle gas volume fractions (GVF) as high as 85%, and in laboratory tests on oil and water achieved a GVF of 94%. These trials are all documented and were published in the technical press. In them we met, or exceeded, all the operating criteria dictat ed by the oil companies at that time.

During the 1980's, frequent discussions took place with the industry on operat ing requirements and commercial prospects for the MPP product. These have continued ever since. Anything involved with subsea operations naturally involves large development costs and access to the special offshore environ ment. Opportunities for this have been scarce and so has funding assistance.

Lack of information from the oil industry on their specific subsea operating requirements has been of great concern. It has significantly slowed the pace of development and many questions, put several years ago, still remain unanswered.

Over many years, we have experienced very good results from field tests with the screw type pump. These showed clearly that it was technically superi or to many other types currently under investiga tion. For example, in an extended test in offshore Malaysia, payback periods - in terms of incremen tal oil pro duced - of less than 1.4 months (capital cost of pump) and 4 months (when installation charges were included) were achieved.

Currently, the unique features of the multiphase pump are rightly being evalu ated in surface (land and platform) applications, although at least two or three subsea trials are currently taking place or planned. On this evidence, there has been no substantial change in industry attitudes since 1985 and confirms our view that a commercial market will not become a reality until 2000, or 2005, if at all.

JEAN-FRANÇOIS GIANNESINI
Nomad SA

Jean-François Giannesini is the chairman of IFP and CEO of Nomad SA, located in Nanterre, France. As a director of Institute Français de Ptrole (IFP), he has been active in the development and promotion of several new technologies in the petroleum industry. He was chairman of the Deep Oil Technology Conference advisory board in 1993.

For about two years we have been promoting, mainly in the North Sea area, the use of multiphase boosting for subsea production applications, but without seeing any firm commitment from operators to use this technology in an actual project. Multiphase boosting technology provides good potential for the development of marginal fields but, up until recently, these have not been considered as a first priority by oil companies.

Industry attitudes on multiphase pumping (both surface and subsea) have the taste of deja-vu and are a reminder of the attempts to introduce horizontal drilling in the early eighties. With these, it took three years to see the first real move and then about eight years for the technology to become widely accepted. In terms of acceptance, multiphase boosting is where horizontal drilling was in 1984. Let us keep in mind that innovation always needs time to be accepted and, especially in an industry where investments are so huge, it is prudent to exercise caution in technological choices.

There are indeed several factors which prevent companies from taking the plunge. But, the prime one is partly psychological. How many operators consider surface boosting possibilities when multiphase pumps are discussed? Most think immedi ately of a subsea production facility with all its complications of electrical cables, umbilicals, wet connectors etc. In other words - a nightmare! They do not realize that in most water depths of less than 1,000 feet, there exist many opportunities where efficient, reliable and cost-effective multiphase pumps could be employed. There could also be hybrid prospects where the pumps are subsea and all the ancillaries are at the surface.

In the application of multiphase pumps, we should not go directly to the most difficult applications, but start with surface boosting applications. Once we have demonstrated the advantages of the technology on the surface, we can then approach subsea applications with more confidence and considerably less cost.

A second factor is the legitimate fear of problems connected with the formation of hydrates and wax buildup. Considerable progress has been made in under standing both these major potential obstacles. New families of additives have been developed and tests in laboratories and the field have been encouraging. We need to have better understanding within the industry of what research is achieving. Fear comes from ignorance and communication is the best way to fight against it.

A third factor impacting decision-making is the lack of confidence in our ability to accurately predict flow conditions. Multiphase flow is by nature transient. Here also our industry must be informed on what development programs are achieving.

But, we are making progress. Two years ago the questions were very basic and primarily about the pump. Did it work? For how long? Is it reliable? Neverthe less, I still cannot make a prediction when we will see a full system in commercial operation.

IMO's multiphase pump is designed for surface use, but easily converted for subsea applications.

JOHN COTTON
Kvaerner Energy

John Cotton is product manager for the Kvaerner Booster Station (KVS), a product of Kvaerner Energy in Oslo, Norway. He has been responsible for the KBS, a system that has been under development since 1985. KBS has been developed in conjunction with Esso and Saga and recently successfully completed a wet testing program.

Development of multiphase pumps looks like a Catch 22 situation. New technology will not be acceptable until proved by experience, but (in the case of multiphase boosters in subsea operations) only the end user has the facilities and the environment where the new technology can effectively be proven.

A developer of new technology will never be able to eliminate all the unknowns by testing. People are naturally apprehensive of something on the fringe of their experience, even under closely simulated conditions. This attitude is prevalent in marketing of our kind of booster station and is probably experienced by all developers of new technology. We certainly sympathize with the MPP manufacturers.

It really is up to the oil companies to carry the development into the field trial stage.

ALBERT RICHTER
Leistritz Pumps

Albert Richter is a consultant to Leistritz Pumps in Houston on multiphase pumps and production technology. He has been active in Deepstar's Multiphase Transport and Equipment Committee. His career in the oil industry includes many years on research assignments with Texaco's Exploration and Production Technology Division.

Several major oil companies have multiphase pumps under evaluation in surface tests. In most cases, the installations have met, or exceeded, performance requirements. Some of these tests on live wells have revealed conditions that were not known prior to the test starting. Reservoir and well conditions used to specify the pump have revealed hitherto unknown factors. The learning process and benefits can be hastened by more installations and the prompt publication of results by operators.

All oil companies have their proponents of multiphase pumping. But, they also have their skeptics, many of whom still remain unconvinced. Although much of the basic technology utilized in the multiphase pump has been in use since the turn of the century, the major development initiative by the pump manufactur ers has taken place only over the last few years.

In contrast, separators and individual oil and gas lines have been around since the beginning of the indus try. Long term reliability of equipment, necessary technological developments to address changing conditions, and general acceptance of a new technology, all remain factors in multiphase pumps gaining wider approval. In this respect, the Deepstar Multiphase Transport and Equipment Committee's work in providing a forum for the interchange of news and views on the technology has proved very useful to the 16 oil companies and over 40 vendors who participate in the program.

Several prototype subsea multiphase pumping systems are under development and testing. As these projects proceed and results are circulated, then confidence in this technology will grow.

Leistritz multiphase unit combines a host of well-known technologies

JON SVAEREN
Framo Engineering

Jon Svaeren is sales manager for Framo Engineering A/S in Norway He is a mechanical engineer with 16 years of experience with the Framo group of companies. His last 12 years have been spent in the oil industry on the development of pump systems and subsea production systems.

It is not a question of either multiphase boosting or subsea processing. In each case, specific subsea applications will dictate what is the right solution. However, given the current operating successes and status of the different pump concepts, then multiphase pumps offer, at the moment, a distinct edge over a subsea processing system. This is in terms of development status, simplicity, cost, subsea marinization, running/retrieving operations etc., all compared on a like-to-like basis.

The pumps available today should be a good tool for a lot of current applications in both retrofit and new projects. Their further develop ment is ongoing, and the ultimate goal of optimum performance can only be achieved through field experience.

The multiphase pump system (SMUBS) that was delivered to the Shell Draugen project is currently operating very successfully subsea in 270 meters water depth. The system was designed with easy subsea installation and retrieval in mind, and awareness of all the interface and control requirements that are so important for subsea operations.

We have a topside machine already delivered to the Gullfaks A platform in the Norwegian North Sea, and an electric subsea booster pump has been in operation for over a year. Multiphase pump technology is therefore available on a commercial basis and provides operators with a new tool to develop offshore fields in the most cost-effective manner. What is missing is the opportunity to gain experi ence.

Although primarily developed as a method of boosting the multiphase flow of wells, MPP can play a great role in providing flexibility where changing reser voir characteristics such as falling reservoir pressure, increasing GORs (gas-to-oil ratio) and water cuts etc. are encountered. A major advan tage of the equipment is its ability to further enhance the production levels of good producers, even right from the very beginning of their operating lives. It is a win-win situation with low commercial risk.

Subsea multiphase boosting technology obviously has its greatest potential in the deepwater projects where static height can be a major problem. Howev er, there are many other offshore fields with less arduous conditions, where MPP technology can be very beneficial in terms of providing artificial lift and as an alternative to gas lifting and subsea separation. Some examples are:

1. Gas-lifted subsea well production where the amount of available gas is becoming inade quate.
2. Subsea wells where the water cut has increased to unacceptable levels.
3. Tie-in of additional subsea wells to existing infrastructure where pressure loss across existing risers is a problem.
4. Subsea wells with high emulsion problems.

Utilization of multiphase pumps in subsea retrofit operations will always be more cost-effective than alternative mudline or downhole boosting meth ods.

Topside and land installations can also benefit now that MPP technology is becoming commercially available. Some potential applications include:

1. Rationalization of land based production facilities.
2. Increased reach of satellite wells.
3. Increased reach of unmanned wellhead platforms.
4. Boosting of low pres sure manifolds to common headers in surface installations.
5. Balancing wellhead pressures of individual wells, or wellhead systems, into common headers.
6. Permitting good wells to produce at their optimum levels (by application of a multiphase booster to the weakest wells) thus enhancing total production of the entire facility.

RICH GATTERER
Warren Pumps

Rich Gatterer is manager - petroleum market for Warren Pumps (IMO Industries) of Warren, Massachusetts (US). In recent years, IMO has supplied a number of multiphase pumps to both the petroleum and general industry for surface applications in various parts of the world.

Developing and producing a reliable subsea multiphase pump system can, in many cases, be compared to going to the moon. Equipment must be developed to operate in inner space where the environment can be nearly as inhospitable as that in outer space.

Some of the leading oil companies have recognized the magnitude of this undertaking and have organized various formal and informal programs that bring together companies with various expertise to work on this challenge. Pump manufacturers, for their part, are concentrating on the heart of the system for conveying a mixture of gas, oil, and water, sometimes including sand, to the surface. The pumping system comprises many sub-systems, including special sealing, lubrication, and control systems. This pumping system will naturally have to be integrated into the complete subsea environment.

Development of this type of application naturally proceeds with many fits and starts as users and suppliers exchange ideas about what is most desirable and what is technically feasible. All of the current multiphase programs are at this give-and-take stage. Consideration is being given to matching up to existing hardware, optimum operating rates, equipment capability, and of course, economics. Over time, the exact operating conditions will solidify as users and pump manufacturers jointly learn what is economically feasible.

Pump manufacturers expect development will proceed in stages with breakthroughs in certain areas leading to progress in others. Work being done on platform-mounted multiphase systems will naturally fuel progress on subsea systems. And, work by others on everything from installation/retrieval issues to pipeline interface and umbilicals, will have considerable impact along the way. Development of technology such as this never proceeds along a direct path, but along many paths until a solution is discovered.

BOB PLATT
Ingersoll-Dresser

Bob Platt is manager of rotary pumps for Ingersoll-Dresser, Chesapeake, Virginia (US) on a worldwide basis. Ingersoll-Dresser has been a major supplier to the petroleum industry for many years and currently is introducing a new generation of multiphase units for oilfield use.

Multiphase pumping is proving to be a reliable technology throughout the world. Previous tests in the laboratory and the field have shown that MPP systems can handle a wide range of the oil industry's production requirements. As flow rates and differential pressures increase, so does the challenge to meet them. MPP systems have so far kept pace with industry requirements. Slowly, we are seeing this worldwide market expanding as familiarity with this exciting technology grows, and operators become more comfortable with it.

Until now, field evaluation of MPP systems has been in surface locations, but interest in subsea applications is growing. This will entail new technologies, new challenges, and new risks that will require pump manufacturers to take a more expanded system-wide view of things rather than just focusing on their pump hardware. For example: physically installing the equipment subsea, accessibility, maintenance, and corrosion resistance are only a few of the new problems which will be of concern to the pump manufacturers. For many this will be completely new territory. The ones that do not have the capability to do it themselves will be forming alliances, on a project-by-project basis, with specialist marine engineering constructors and other major contractors serving the offshore industry in order to offer a complete package.

Development work on new pumps for multiphase booster service is ongoing. New designs incorporating significant enhancements of gas-handling capability, lower power consumption and decreased installation and operating costs will be introduced shortly. We feel that our displacement pumping heritage and equally extensive submersible pump experience positions us well to exploit the unfolding market opportunity in MPP technology.

GIOVANNI CHIESA
Snamprogetti SPa

Giovanni Chiesa is group leader for subsea technology with Snamprogetti SPa in Milan, Italy). He was project manager of innovative systems development in conceiving, designing, integration, and installation of multiphase pump packages for Agip at Prezioso (Sicily).

Development of multiphase boosting is in a closed loop. We need to identify a technical and commercial means to break out of this vicious circle. This requires clear identification of the requirements of individual market segments and demonstration of where the multiphase pump can provide an attractive solution to operator needs. Competing directly with the multiphase booster may be less innovative (but traditionally safe) methods. Good coopera tion between manufacturers and users, in the form of JIPs (joint industry projects) or similar, is therefore essential to identify what is required and implement action.

There is no unique multiphase boosting solution to all the wide variety of reservoir and site conditions. Each of the many multiphase designs on the market has its own preferred segment, but, some overlap obviously exists. Some valid questions:

1. To what extent do the present designs fit current application scenarios?
2. To what extent do current (and past) tests demonstrate the viabili ty of the equipment to meet operator needs?
3. What changes, including expansions or extension of current tests, are required to cover the wide variety of operating conditions that the equipment will face in the field?

With present low oil prices there is no strong incentive for oil companies to develop and apply new technologies. In respect to multiphase pumping, some oil companies are heavily involved in development programs but this is for their own system. Other companies may look at the achieved technological accomplishments now available, but will contribute little innovative input. There is low confidence in the current level of technological maturity that MPP has achieved. As a result there is no established market.

What should be done and how can pump manufacturers establish credibility with operators? We need to recognize that there are many issues related to multiphase operations. Flow conditions for fluids and gas vary considerably, not only between wells but also in the same well during short and long term periods. Hydrate and wax buildup can create unique and severe operating stresses on the system. Corrosion may also be a problem. The design and operating characteris tics of the related equipment (flow meters, manifold and piping layout, power supply, etc.) can all impact the operating performance of the subsea multiphase booster. An action program should include the following:

1. Calibration of equipment for specific operating scenarios.
2. Identification of all specific operating condi tions.
3. Qualification of equipment against defined specifications.
4. Recogni tion that there is a need for a global solution integrating many different skills and disciplines.

Pump manufacturers cannot go it alone. There is an urgent need for super parties to lead and coordinate the actions of the suppliers and the needs of the operators to bring all processes to maturity.

Conclusions

Subsea multiphase pumping is taking place now in at least two key offshore projects and others will surely follow.

• Ready to go: Multiphase pumps are today commercially available for both subsea and surface applications and provide a cost effective solution to many of the problems that are currently being addressed with traditional methods. The current commercial success of the SMUBS program points to the growing acceptance of MPP systems and their wider employment in subsea field developments.
• Multiple uses: The ability of MPP systems to boost the production of good wells and enhance instead of enable total production potential of a field is just one of the possibilities that Jon Arve Svaeren (Framo Engineering A/S) touches on in his comments. The multiple use possibilities of the MPP should be of great interest to all engineers in reservoir, pro duc tion, process ing and field development disciplines.
• Slow progress: The industry has always maintained a slow pace in putting new ideas to work. Talk to any purveyor of horizontal drilling technology or coiled tubing for some real war stories! And, when tight budgets and reduced technical staff levels in oil companies are considered, then tradi tional practices and long proven technology are always prudent. All of this makes for a protracted acceptance period for innovative proposals and has undoubtedly blunted the appetite of some suppliers to continue. However, there is ample evidence that past tough times have also inspired new ideas and their implementation in the field.
• New players: There are other factors at work. The new field development engineer ing contractors that are now emerging offshore, may provide the vital link between the operators and manufacturers that MPP systems need. They will provide guidance in the interface with ancil lary equipment, the better appreciation of operating require ments, and most important, they will take total responsibility for making the entire system work. Perhaps these are the super parties that Giovanni Chiesa mentions.
• Timing: The timing is right too. The development of marginal fields, frequently not in ideal locations, is going to be with us for a long time. Development of these are going to require some radically new depar tures from our traditional practices. MPPs will play an important part here.
• Communications: The high cost of producing equipment for subsea opera tions and the extended time required by oil companies to mature operation al parameters for their off shore projects invariably test the stamina and persistence of the manufactur ers. Improvements in communica tions - as Albert Richter highlighted via Deepstar - could certainly yield benefits to all parties in promoting a better under standing of issues and perhaps provide some cost savings.
• Other markets: So far, we have only discussed MPPs in subsea environ ments, but, if other indus try experience (including the space program) is anything to go by, a product as versatile as the multiphase pump will also be widely utilized in onshore produc tion opera tions and other industrial activity.

Compilers:

Ken Barker is senior consultant with Lovie and Company in Houston. He is an internationalist with wide experience in most aspects of oil and gas operations throughout the world. His 40 years experience includes work in the drilling, production, pipelining and downstream processing sectors of the market. Assignments have covered feasibility studies, project development and negotiation, new product introduction and training.

Peter Lovie is senior consultant with Lovie and Company in Houston. His responsibilities have included consulting for oil companies on the application of multiphase transport systems in new field developments. He has been active in the Multiphase Transport & Equipment (200) committee, and in 1990-1992 led the development of the GLASS subsea separation and single phase booster pumping system for a group of Gulf of Mexico operators.

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