How these and related factors affect subsea processing design are discussed below. The value of subsea processing is determined primarily by reservoir characteristics and water depth. Well productivity index (barrel per psi drawdown or PI), which is a function of reservoir permeability, is one of the keys. A high PI will leverage the reduced backpressure provided by subsea processing to higher production rates. This can have enormous economic implications for low-pressure reservoirs in deep water.
As oil and gas production moves into deeper water, the cost of surface production platforms becomes prohibitively high. The industry has found that surface facilities must be kept to a minimum and shared by satellite fields to be commercial. Subsea processing is a key toward a cost-effective, "hub-and-spoke" development (Figure 1), allowing the industry to operate successfully in deeper water. Subsea processing refers to the separation of produced fluids into gas and liquid--or gas, oil, and water--for individual phase transport and disposal (in the case of water). The liquid stream can be pumped to a central facility for final processing.
Separation of gas and liquids is a key processing function for any production operation. Several approaches exist to accomplishing this separation subsea, as described on this page. Which is most appropriate to use depends on the fluids and conditions specific to the particular location. By separating the gas and liquid phases and pumping the liquid stream, this simplest of systems will capture most of the benefits of subsea processing. It will reduce backpressure to the wells and eliminate problems associated with multiphase flow.
Some of the technologies, such as mechanical and control devices commonly used in subsea well and manifold systems, are well developed and can be considered off-the-shelf items. Many of the emerging products are well-proven surface components modified for subsea application. As in any integrated system, a shortcoming in any one of the links will impair the performance of the whole. A clear understanding of the process and all its parameters is the first step toward a successful design. As in surface facilities, knowledge of the produced fluid properties, rheology, and flow characteristics are critical. Luckily, whether the process is carried out on the surface or a thousand meters subsea, the process is the same. However, effects of the environmental conditions may be more dramatic and detrimental. Fluids with high foaming tendency will complicate the design and may require mechanical or chemical solutions. For subsea applications, a passive mechanical foam-breaking device (such as a low-shear inlet momentum breaker) is preferred over the more costly to install and operate chemical injection systems. For three-phase separation, the more complex oil/water emulsion/dispersion chemistry will come into play, along with the viscosities of the oil and water and changes in water cut with time. Whether an oil/water mixture will form a stable emulsion or a more manageable dispersion often depends on the small concentrations of surface-active impurities in the fluid.
Subsea processing using subsea separation and pumping technologies has the potential to revolutionize offshore oil and gas production. When combined with relatively mature subsea production technologies (see subsea chapter on well systems, manifold, pipeline, power and control umbilical, and so on), it can reduce development cost, enhance reservoir productivity, and improve subsea system reliability and operability. Over the period from 1970 to 2000, millions of dollars have been spent to develop subsea separation and pumping systems. But because of unresolved technical issues, along with a lack of confidence and clear understanding of the costs and benefits, industry has not rushed to deploy the technology on a commercial basis. However, as the industry moves into remote deep and ultradeep water, various degrees of subsea processing are becoming more common. In deep water, the technology can enable hydrocarbon recovery from small reservoirs that are subeconomic by conventional means, ...
Subsea processing using subsea separation and pumping technologies has the potential to revolutionize offshore oil and gas production. Between 1970 and 2000, millions of dollars were spent to develop subsea separation and pumping systems. But because of unresolved technical issues, along with a lack of confidence and clear understanding of the costs and benefits, industry did not rush to deploy the technology on a commercial basis. However, as the industry has moved into remote deep and ultradeep water, various degrees of subsea processing are becoming more common. The benefits of subsea processing have been recognized for several decades.
The costs of subsea boosting systems have been reduced by adopting three primary strategies: simplifying the system design to reduce weight and cost, simplifying the installation and intervention, and reducing complexity and risk. This study examines how subsea processing (SSP) can develop into an important enabling technology for future ultradeepwater-field developments and long-distance tiebacks. Emphasis on identifying more-efficient subsea boosting solutions has led to a number of initiatives in the industry.
This study examines how subsea processing (SSP) can develop into an important enabling technology for future ultradeepwater-field developments and long-distance tiebacks. As it has since 1969, the world came to OTC to make critical decisions, share ideas, and develop business partnerships to meet global energy demands.
Operators are increasingly using existing offshore infrastructure for asset life extension, and developing new marginal stranded fields rather than develop new large greenfields. Subsea processing is an enabling technology in this goal. Subsea processing is an evolving technology in ultradeepwater development and has the potential to unlock a significant amount of hydrocarbon resources. In this paper, the authors have reviewed the application of subsea systems in 12 deepwater fields and discussed the significance of each.
Pioneer shut in 8,000 BOE/D production in its West Panhandle field in Texas on 6 March due to a compression station fire. Planning to use idle compressors, production is expected to restart later this month or in early April. As compressor stations are added to the natural gas gathering and transmission networks, the potential noise issues are coming under increasing public scrutiny at the same time as regulations are being rolled back.