More innovations needed for world offshore environments

Deepwater exploration is gathering momentum around the world, spurred by a number of recent sizable discoveries and progress in development of new technologies.

However, delegates attending an Institute of Marine Engineers conference in London Apr. 8-9 were warned that deepwater technology has not progressed far enough to ensure success of planned projects.

Showing how research and development are likely to proceed, speakers detailed work on a new reservoir management tool, an all-electric seabed oil processing unit, and new technologies for remote intervention.

Mark Staunton-Lambert, research manager of Centre for Marine & Petroleum Technology Ltd., London, said: "In today's business climate, development techniques have to be economical, functional, and reliable.

"The competing demands for developments that are good, cheap, and fast suggest that planning and design work have to be advanced both quickly and confidently.

"Since deep water developments are not yet mature, there is still plenty of novelty and innovation being tried."

Staunton-Lambert said there should be three main targets for future deep water research and development: transfer and utilization of existing knowledge; new and better methods for design and analysis of floating structures; and case studies to demonstrate the new methods in realistic designs.

To improve knowledge transfer, Staunton-Lambert said experimental data, theoretical or computational analyses, and selected specialized computer programs should be made available in robust and readily usable software. "Better tools for planning, design, and analyses of candidate systems, especially moorings, risers, and hull configurations, must be priority deliverables of the research," he said.

Improvements in floater design are needed to enable characteristics of deepwater applications, such as strong variable direction currents, taut-line moorings, and green water on decks, to be properly taken into account.

"These methods also need to be presented as computer programs," said Staunton-Lambert. "Better know-how for assessing the real capabilities and capacities of the deepwater innovative design solutions are also priority deliverables."

Finally, realistic case studies would help to broadcast lessons learned from development to date and enable feedback to research programs in the form of technical improvements and direction of future research.

Reservoir control

Ian Phillips, lead engineer for integrated solutions at Halliburton Manufacturing & Services Ltd., Aberdeen, told delegates that reservoir management innovation is key to squeezing more out of fields.

Halliburton has joined Petroleum Engineering Services Ltd. (PES), Aberdeen, in development of a 'smart' downhole tool called Surface Controlled Reservoir Analysis & Management System (Scrams).

The Scrams tool incorporates sensors that feed data to a downhole microprocessor, which sends data to surface and can also be used to adjust downhole conditions through inflow control devices (OGJ, Apr. 14, 1997, p. 34).

Phillips told delegates that primary technologies to break a reservoir into a series of discrete management intervals, as a way of improving reservoir management, may already exist as main components in Scrams.

Scrams consists of an electrohydraulic control and power system and a hydraulically set packer controlled through a downhole microprocessor; and an electro-hydraulic variable choking device to regulate flow from each interval (see diagram [32338 bytes]).

PES has secured a contract to provide Scrams for use in North Sea fields by Shell U.K. Exploration & Production. Norway's Den norske stats oljeselskap AS is also believed to be considering using Scrams.

"The new field development of the future will be profoundly different from that of today," said Phillips.

"Reservoir description data volumes will increase by several orders of magnitude, transforming understanding of the reservoir structure and the ability to predict fluid flows.

"Production behavior data will also increase dramatically, allowing production optimization to occur in real time. This improved understanding offers the prospect of increasing recoverable reserves beyond the typical 35% achieved at present."

Seabed processing

David Appleford, managing director of Alpha Thames Engineering Ltd., Upminster, U.K., updated delegates on his company's All-Electric Seabed Oil Processing (Aesop) system, targeted for first installation in 1998-99.

Aesop was conceived in response to the trend toward seabed systems being completely electrically powered and controlled, said Appleford, to enhance stepout distances and enable deepwater installation.

Aesop was said to be a complete seabed processing and boosting system, installed and retrieved with a supply vessel and a workhorse remotely operated vehicle.

Appleford said discussion with manufacturers of separation systems had indicated that future development could include additional subsea separation operations, such as separation of water from oil and cleansing of produced water so it can be ejected on site.

"The principles of the technology could also be applied to multiphase systems and multiplexed systems," said Appleford. "It is evident that the need for all-electric systems has increased.

"Diverless, subsea processing systems such as Aesop, which are electrically powered and controlled, with electrical rather than hydraulic umbilicals, offer an attractive solution to the problems presented by deep water and sites well away from platform facilities."

Remote intervention

Geoff Pegman, managing director of U.K. Robotics Ltd., Manchester, told delegates of developments to date in remote intervention, and of promising technologies for future developments.

Pegman identified the most promising technology as the use of high fidelity three dimensional graphical systems, commonly known as virtual reality (VR) systems, for off-line and on-line support of remote interventions.

"The first and most obvious use of these systems," said Pegman, "is as a virtual camera or mimic, in which a model of the remote manipulator is driven in tandem with the real manipulator in an overall model of the environment." The next stage in development would be use of VR as an on-line rehearsal facility, said Pegman, enabling a slave robot arm to be temporarily suspended from being driven while the control system drives the mimic.

"In this mode," said Pegman, "the mimic can be used for rehearsing a move before attempting the same with the real robot arm. It is even possible to teach a series of moves in the virtual world and replay them on the real slave arm."

Robots are not widely used in the petroleum industry, and this was attributed to poor dissemination of knowledge of capabilities, along with poor implementation of early robot systems.

"To meet some of the challenges facing subsea industry," said Pegman, "it is important that developers and operators work together in producing cost-effective, high usability systems that take advantage of recent progress in computing and control system technology."