Justin Tuohy Publications

Deepwater Flexible Risers & Flowlines – A Decade of Case Studies in Brazil

Published: November 2002 | DOT International Conference and Exhibition XIV – “Flexible Solutions for Today and Tomorrow” –  | November 13 – 15, 2002 | New Orleans, Louisiana, USA

Abstract

Offshore oil and gas exploration in deep water continues to provide the industry with new production opportunities and significant technical challenges. Less than three decades ago saw the first installation of flexible pipe in offshore oil and gas developments. Flexible pipe solutions have become synonymous with the use of floating production systems spanning the water column in remote locations, connecting subsea structures with the surface to facilitate the retrieval of hydrocarbons and the injection of water and gas.

Remarkable advances have been made in the development of unbonded flexible pipe structures to meet these challenges, driven to a large extent by Petrobras’s pioneering deep water developments offshore Brazil. These developments have been made possible through research programs funded by Petrobras. Discovered in 1985, the Marlim field, located in the northeastern part of the Campos Basin, was the first field to benefit from these programs. The development of this field was underpinned by the 1986 PROCAP research program focusing on record breaking technologies required to develop not only the Marlim field, but also future deepwater fields, in water depths down to 1,000m.

By 1990 Wellstream had designed and manufactured its first dynamic flexible riser for operation in 1,000m water depths which laid the foundations for Wellstream’s continuing long term deepwater relationship with Petrobras. In 1999 Wellstream set new standards in the development of flexible pipe by becoming the first company to qualify flexible pipe products to 2,000m water depth for the Roncador field, thus meeting the challenge set down by Petrobras in the PROCAP 2000 research program.

Over the decade of the 1990s, significant design and manufacturing challenges were overcome through inhouse research and development programs coupled with support from TCAs(a) with Petrobras. This paper provides an important appraisal of the development and advancement of flexible risers and flowlines for deepwater applications. The information is captured in a number of case studies spanning different field development projects in water depths of 650m to 2,000m over the last ten years. The paper concludes with a summary of the challenges faced in future developments over 2,000m water depth.

 

Authors:

Tuohy, J., DePaula, M. T., Plank, R. J., Santos, S., Martin, S.

Justin Tuohy Publications

The Application of Unbonded Flexible Risers & Flowlines in Hostile Environments – Shallow Water Case Studies

Published: November 2002 | International Conference on the Application and Evaluation of High-Grade Linepipes in Hostile Environments | November 8 – 9, 2002 | Yokohama, JAPAN

Abstract

Unbonded flexible pipe has a proven track record in the offshore oil and gas industry for more than 25 years. The product is synonymous with the use of floating production systems spanning the water column, connecting subsea structures to facilitate the retrieval of hydrocarbons, provision of water and gas injection systems and the export of processed or semi processed fluids to main trunk pipelines, to onshore, or to floating storage units. Unbonded Flexible pipe is a technically complex multi-layer structure of helically wound metallic wires and tapes and extruded thermoplastics. Applications of flexible pipe solutions in service encompass high temperatures of up to 130ºC, design pressures as high as 100 MPa, with sour service fluids for typical internal pipe diameters up to 16-inch for production applications, and even larger in export applications. Severe environmental conditions; extreme wave and current loads coupled with significant vessel excursions, challenge the design and construction of flexible pipe structures. End fittings are a critical component of the flexible pipe system. They must assure a leak tight transition between subsea and surface facilities, during the applied severe environmental loads and thermal cycling due to start-up and shutdowns, with changes in the fluid barrier material properties over the designed service life. A summary of the results of analyses and tests conducted to verify the integrity of the end fitting with thermal cycling and fluid barrier changes due to high temperature production fluids is included in the case studies presented.
This paper demonstrates the ability of unbonded flexible pipe solutions in the form of dynamic risers and flowlines to be the key enabler for the production of hydrocarbons to floating production systems in hostile environments.

 

Authors:

Tuohy, J., Sheldrake, Dr. T.

Justin Tuohy Publications

Flexible Pipe Technology – Spanning the Water Column in Deepwater Field Developments

Published: November 2002 | OSEA (Offshore South East Asia) Conference | October 29 – November 1, 2002 | Singapore

Abstract

The recovery of hydrocarbons in water depths up to 2000 metres to date and in the future beyond these water depths, presents significant technical challenges to the designers of recovery systems. Met-ocean characteristics, relatively low reservoir temperatures and pressures also serve to compound these challenges. Flexible pipe has become synonymous with the use of floating production systems spanning the water column, connecting subsea structures to facilitate the retrieval of hydrocarbons and the injection of water and gas. Innovation to unbonded flexible pipe’s technically complex multi-layer structure of helically wound metallic wires and tapes and extruded thermoplastics has ensured that the
product remains one of the key enabling technologies, particularly for deepwater developments. Recent developments include the application of flexible pipe technology in hybrid risers systems, large diameter export loading lines, and topside high-pressure applications.
This paper discusses Halliburton Wellstream’s approach to the use of innovative design techniques to ensure that the company is positioned at the forefront of new flexible pipe technologies. Case studies will be used to illustrate some of the existing technological breakthroughs provided by Wellstream and already in operation at various water depths world-wide. An insight into a typical comprehensive test programme associated with the qualification of a new product is also provided.

 

Authors:

Tuohy, J., Martin, S.