Greenfield recovery solutions
Advanced subsea technologies enable field developmentThere are a number of solutions to address low reservoir pressures and heavy oil challenges often found in greenfield applications. Until recently, many of these solutions were not available for application in a subsea field. However, advancements in subsea processing technology now include:
- Subsea water injection for pressure maintenance and sweep
- Subsea separation to widen the application of water injection and other pumping and artificial lift techniques, as well as for additional benefits from separating the produced phases on the seabed
Increased oil recovery in brownfield application
Improving your project & project portfolio
Subsea processing technologies can be a decisive factor when assessing viability of complex greenfield developments. To date, when applied to a greenfield development, the technology has been enabling. In other words, without subsea processing, the field would not otherwise be economic to exploit. Low, natural production rates result in sub-par return on investment (ROI) and delayed payback versus competing projects. In many cases the reduced revenue rate over the life of field means that the projects' present value and estimated ultimate recovery can look weak versus other projects.
Subsea processing can help achieve faster payback, accelerate production and result in improved ultimate recovery thereby taking some projects from below average producers to world class producers. Additionally, development CAPEX can be reduced through the avoidance of applying alternative costly solutions like flow assurance mitigation.
Subsea processing can improve greenfield performance
Project performance can be improved by:
- Enabling projects that would otherwise not meet project hurdle rates
- Upgrading individual project metrics to better compete in the internal market for capital
- Upgrading overall project portfolio with a higher proportion of higher quality projects
Enabling the development of complex reservoirs & fields
Subsea processing has enabled the development of complex reservoirs in difficult subsea environments including:
- Under pressured subsea reservoirs. These reservoirs may lack the energy to produce to the surface in economic rates or volumes
- Heavy oil and/or low permeability subsea reservoirs. Available reservoir energy is insufficient to transport the fluids through the reservoir, wells and flowlines
- Tiebacks. Produced fluids have to overcome the pressure drop associated with being transported over long distances. Typical scenarios include a satellite tieback to a long distance host, or transport directly to beach. These scenarios may be considered for developing large, remote gas fields or fields in the arctic
Subsea boosting, subsea separation and pumping, and gas compression allow energy to be added to the produced fluids. This increases production and reserves by reducing the backpressure on wells and reservoirs. Separation allows efficient energy management as well as increased flow assurance benefits. These benefits are realized when the field begins operation, not just later in field life.
In greenfields, gas-liquid separation is commonly applied in conjunction with boosting as a technique to recover difficult-to-produce oil. In deep water fields, this combined solution enables higher efficiency pumping, minimizes flow assurance risks, and diminishes tieback limitations. It’s also effective in enabling the production of complex reservoirs containing heavy, viscous oil and low pressures. This approach has been successfully applied inShell’s Perdido and Parque das Conchas projects and Total’s Pazflor.
Avoiding the need for surface platforms
As subsea processing technologies advance, it is becoming possible to eliminate the need for surface platforms. Today, subsea gas compression can be used to condition and compress the gas for transport to shore. Additionally, tiebacks to remote hosts can be made over increasing distances. In the future, it may be possible to move more complicated functionality that is currently undertaken by surface platforms to subsea.
FMC Technologies is leading the development of technologies to enable such a future. FMC is successfully enabling the decommissioning of existing surface facilities for Brownfield applications.
Maintaining production throughout field life (flow assurance)
Subsea processing addresses many potential operational or flow assurance challenges for deepwater subsea projects. Subsea processing solutions can reduce the related capital costs of providing flow assurance prevention or mitigation. And, at the same time, it can increase production and reserves recovery.
For instance, subsea pumping and subsea compression can change the multiphase flow regimes of produced fluids to move operating conditions outside of problematic flow regimes. This can be applied as an alternative to providing multiple flowlines and export pipelines, or shutting in production. Additionally, subsea separation can split the produced fluid phases to alter the composition of oil, water and gas within flowlines, risers and pipelines to avoid hydrate formation. This can avoid costly hydrate prevention solutions like pipe-in-pipe flowlines. Equally, in shutdown conditions, subsea separation can allow the pressure of the deepwater subsea system to be reduced below that of the hydrate formation pressure.
A broader range of options for field development and projects
Subsea processing can provide an alternative to:
- Topsides architecture - Subsea processing potentially eliminates entire surface platforms. Subsea-to-beach developments are now possible for gas fields with subsea gas compression. For arctic developments, subsea separation and pumping can enable transport to a very remote hub for further processing.
- Subsea architecture - Subsea processing enables more possibilities. More options are now possible including a low pressure subsea hub with subsea separation and pumping.
- In-well ESPs - Subsea processing offers more reliable options for adding energy. In-well ESPs have potentially low reliability and high intervention costs. Other options including mudline boosting and the combined solution of subsea separation and pumping can potentially add energy more effectively.
- Gas lift - Subsea processing widens the application for gas lift. Gas lift system designs are influenced by gas lift volume and gas lift pressure. In applications where there are high gas fractions or long step-outs, pressure drops are increased. In addition to pressure drops, surface gas compressor capacity can pose another limitation. The addition of mudline boosting or the combined solution of subsea separation and pumping can potentially add energy more effectively.
- Water injection - Subsea processing widens applications for injection techniques. Water injection capabilities are usually preinstalled topsides, often ahead of knowing whether an aquifer is present or not. Subsea water injection of produced water or raw seawater using subsea pumps can take weight and space off the topsides facility and provide an option to retrofit once the presence of aquifer drive is confirmed. This can eliminate the need for high pressure risers for water injection using topside facilities.
These are some of the ways that subsea processing can change the field development scenario. Many possibilities exist. By engaging early in the project lifecycle with FMC Technologies, operators can explore the possibilities before being constrained by early project decisions. Numerous operators have collaborated in early project phases, dramatically changing the field development scheme and significantly improving project economics through the use of subsea processing.
FMC Technologies can provide advice and undertake studies to help you understand how your projects can be improved by subsea processing. This is informed by FMC’s past track record of project delivery and deep knowledge of subsea processing technologies. Find out how subsea processing can impact your field by contacting one of our experts.