Deepwater Field Development and Concept Selection a report by Richard D’Souza1 and Shiladitya Basu2 1. Vice President, Granherne Global; 2. Senior Technical Professional, Granherne Americas
There is general consensus that global demand for energy will increase by 30% by 2030 (see Figure 1). To meet this demand, all energy sources will need to grow: fossil fuels, nuclear and renewables. In this time oil and gas will remain the predominant source of energy supply. The plot in the middle of Figure 1 shows current and projected oil supplies from various sources up to 2025. Of these, onshore and offshore shallow sources (90% of the current oil supply) are projected to decline at 6.5% per year. Deepwater and unconventionals, which provide the rest, are projected to increase to make up the difference. The plot at the bottom shows the importance of deepwater oil production, growing from 2% in 2002 to 8% in 2010. It is projected to grow to 12% by 2015.
This article addresses how one goes about selecting a floating platform for a deepwater development. The large capital expense involved, the uncertainties in predicting reservoir performance and inherent risks in executing these complex projects mean that it is becoming ever more important to select the optimum field development solution. Selecting a floating platform is a subset of this aspect. In the closing sections, a timeline of deepwater floating platforms in the Gulf of Mexico, guidelines and observations on platforms selected from a historical perspective will be presented.
Field Development Planning Cycle
Development planning of a deepwater field is a very structured process because of the high costs and substantial risks and uncertainties involved. The many phases of a deepwater field’s development life cycle are shown in the top row of Figure 2. At the end of each phase is a stage gate where a ‘go, no-go’ decision is made. Project sanction occurs at the define stage gate. The graphic at the bottom of Figure 2 illustrates the importance of a well defined development plan in the phases leading up to sanction. The most ‘value’ is added prior to sanction and is critical to the eventual commercial success of the development plan.
Fundamental Field Development Drivers
There are four major aspects of field development: reservoir, region, site and operator. By far the most important aspect of field development is the reservoir. Its many variables – which include its size, geometry, connectivity, rock and fluid properties, etc. – determine the primary platform functionalities. Every country has a governmental regulatory agency that manages its hydrocarbon resources and each has different rules for acquiring and producing them. These include taxes, royalties, profit sharing agreement (PSAs) and local content requirements, among others. All of these factors will influence decision-making and development strategies.
The availability of shore bases, midstream infrastructure and marine logistical support, which are region-specific, also play a role. Site
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conditions – such as metocean (wind, wave, current, swells), sea-bottom topography, geotechnical, geohazards and seismicity – are significant drivers of platform design, station-keeping, risers and well system integrity. These conditions can vary significantly by region and location.
Each operator has corporate strategies and philosophies that factor into decision-making. This includes supply chain management, standardisation, risk management or hub strategies.
The bottom line is that every reservoir and site is unique, every region has requirements and constraints and each operator has specific strategies; therefore, there is no cookie-cutter approach to field development.
Major Platform Selection Drivers
The selected platform must satisfy all functional, technical and commercial requirements (see Figure 3). Additional considerations, some of which are shared by the field development process, also strongly influence final platform selection. When the market for fabrication yards, installation vessels and deepwater drilling rigs is
The bottom line is that every reservoir and site is unique, every region has requirements and constraints and each operator has specific strategies; therefore, there is no cookie-cutter approach to field development.
projected to be tight, an operator may choose to either lock in capacity to ensure a preferred platform delivery or choose a platform that is less dependent on such factors. Increasing the amount of local content requirement in certain regions can also influence the platform choice. The availability and capabilities of the local market could shrink the choice of selectable platforms.
An operator will also have to abide by corporate strategies and philosophies, such as:
• whether the platform should be for a single field or a regional hub; • whether it should be optimised or standardised; • whether it should be leased or owned; and • whether the field should be developed aggressively or in phases.
Each platform has associated risks, and the risk management philosophy of an operator influences the final decision. Issues that need
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Engineering & Construction
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