ABSTRACT

In line with today's CRINE initiatives, the Subsea Wellhead Control Buoy Offers inexpensive, highly reliable, remote control and monitoring of subsea completions, combined with ease of maintenance and safe operation.

This innovation, which enables a subsea wellhead to be controlled from the surface using a unique design of tethered buoy, offers a cost-effective solution for the economic development of marginal oil gas fields. It was developed as a result of studying the needs of the Subsea Production Systems Market and addresses the steadily growing requirement for the use of subsea well completions. It allows offshore operators and engineering contractors to optimize subsea developments and is particularly appropriate when a new development can be tied back to an existing offshore facility.

Using proven methodology already installed by Oceantech in over 60 locations worldwide, it is possible to eliminate the conventional seabed umbilical and provide an inherently safe and redeployable system whilst saving approximately 50 per cent in capital expenditure. As an unmanned facility, it requires far less equipment than traditional solutions and offers the great advantage of modular repair. The total installation cost is extremely low and as a very flexible solution it can be inoved and reused very cost effectively.

In adopting the CRINE philosophy of standardization, simplification and open communication, the Subsea Wellhead Control Buoy will be offered to the industry as an "off-the-shelf" design configurable to specific development requirements.

Oceantech with its unique 20 year history of SPM control systems, installation and maintenance, proposes to offer the industry a total cost-effective turnkey capability. This will encompass feasibility study, system design through to installation, integration, commissioning and through life support of the total package.

The Wellbuoy Solution (available in full paper)

INTRODUCTION

This paper describes a cost-effective remote system for the control and monitoring of subsea completions. The solution uses CALM buoy technology and significant saving is made when compared to the conventional method.

The solution objective is based upon achieving the following improvements on current subsea methods

  • Increased distance from wellheads to production facility

  • Elimination or Simplification of umbilical requirements

  • Minimised capital and operating costs

  • Ease of interfacing with process platform DCS

  • Redeployment of facility

The buoy philosophy brings together Oceantech's proven capability of

  • Wellhead Control Systems

  • Remote Telemetry Systems (including lightweight hazardous area systems)

  • Emergency Shutdown

  • Buoy Design

  • Umbilical Definition

  • Subsea and Buoy Installation

  • Intrinsically safe PLC's and Radios

The concept is not new and has already been successfully deployed by Oceantech in the control of CALM PLEM valves.

The buoy has been designed to used off-the-shelf, proven and reliable equipment. This therefore reduces any financial and technical risks associated with this proposal. In line with the modern day concepts of Coast Reduction Initiatives for the New Era (CRINE), the solution offered by Ocean Technical Systems Limited, is based on a modular philosophy. Therefore, the individual requirements of development and the operational practices of the client can be met economically.

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