Abstract/Introduction

This paper on System-Modular Management presents an efficient, cost-effective method for the development, operation and control of "smart asset" hydrocarbon reservoirs. This method may be successfully utilised for new, mature, marginal or deepwater fields. The paper describes the method and identifies its operational and cost advantages over other development methods.

The System-Modular Solution

The key feature of the System-Modular solution is the CPU (Central Processing Unit). This is the control and power distribution centre for the whole field development. It comprises a Docking-Manifold and at least two identical System-Modules. Each of the latter accommodates autonomous, system-integrated process, control and power distribution systems. This solution enables fields to be developed by a "building block" approach in which the "building blocks" are configured to meet the needs of any given application but are standardised in that they have common interfaces.

The CPUs can be used to control the entire field and can distribute power to electric or electro-hydraulic trees. In this way, the CPUs can act as the nodes in an intelligent control and power network that covers the entire field, including the wells and the seabed processing system, and which, via communications links, can be controlled from a remote location anywhere in the world.

The equipment within each System-Module is appropriate to the field at the time of installation. However, a "plug and play" approach enables the System-Modules to be readily reconfigured at any stage in field life in response to changing field characteristics or for the introduction of new technology.

This method enables production to be optimised whilst minimising costs and risks. Furthermore, at the end of field life, the entire CPU can be retrieved for re-use elsewhere.

The extraction of hydrocarbons from a reservoir can present several problems. As well as the diminishing production rate, there is usually an increase in the water cut and, in some locations, sand is produced. Slugging may occur as pressure decreases; this often causes problems which cannot necessarily be solved by multiphase pumping especially where there are long distance tiebacks. Furthermore, hydrate formation may be a problem in the export lines as the temperature of the produced fluid decreases.

There is often the perception that there is no economic merit to be gained from further investment in a mature field at this stage, due to the high cost and dwindling returns. Fortunately for those responsible for such fields, the retro-fitting of a System-Modular installation overcomes these problems and extends the life of the field. Furthermore, significant additional advantages are offered, thus rendering the development of the field a viable proposition. For example, with the inclusion of seabed separation, it is possible to tie a field back to a more distant host, avoiding the need for local surface facilities, such as FPSOs, which may be released from the field.

On the seabed, the System-Modules are accommodated in the Docking-Manifold. The Docking-Manifold of a CPU installation is of simple construction and can be fabricated and installed separately from the System-Modules. As it does not contain any actuated valves, control equipment or long lead time items, it can be installed at an early date, possibly during the pipeline installation stage of the development. This provides the opportunity to utilise installation vessels that are in the field at the time. The Docking-Manifold includes piggable header pipes and facilitates the connection of all pipelines and flowlines. The system can include a pigging loop for round trip pigging, or can accommodate diverless pig launchers/receivers. However, it should be noted that, when the system is configured for separation, many production pigging activities might no longer be required.

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