Abstract
The plans for many of the upcoming deepwater projects involve the use of highpower Electrical Submersible Pump (ESP) Systems for Artificial Lift. However, the perception in the industry is that the average run-life currently achievable with such high power ESP Systems is much shorter than what would be dictated by robust project economics, given that intervention costs in these applications can be very high, in the US$50MM – 75MM range. Therefore, the consensus among operators is that there is a need to try and improve the reliability of these systems.
In response to this industry need, DeepStar® recently commissioned a gap study towards identifying the barriers that may be preventing ESP Systems from achieving the desired reliability as well as the additional R&D effort that may be required for the industry to close the existing gap. DeeepStar® provides a forum for deepwater technology development, while leveraging the financial and technical resources of the industry.
This paper presents a summary of the results of this study, including:
the Mean Time To Failure (MTTF) that people believe is currently achievable (i.e.with current technology);
the biggest differences about these applications, which introduce additional uncertainty to the ability of the system to perform reliably;
the main sources of uncertainty regarding each of the major ESP System component’s reliability; and
the tentative plan that was outlined a spart of the project, to address the gaps that were identified.
The Gap Analysis was based on phone interviews conducted with recognized industry experts, on discussions that took place with members of a Technical Committee (TC) that was put in place for the project, and on a broader industry survey conducted through the internet. The proposed go-forward plan consists of two follow-up projects: one focused on improved system design and operational practices, including system monitoring (or surveillance) and control; and one focused on validating the design of key components of concern, for the specifics of these applications, through laboratory testing. The proposed near-future R&D effort has the support of major operators, but still needs to be fine-tuned, with input from the industry, before the actual work can proceed with buy-in and financial support from all of the parties involved.
The Oil and Gas industry continues to move towards more challenging exploitation environments offshore: deeper water (over 10,000 ft), longer tie-backs, deeper reservoirs (up to 20,000 ft below the mud line), and/or with higher viscosity oil. The plans for many of the major projects currently underway in such offshore environments involve the use of relatively high power Electrical Submersible Pump (ESP) Systems for Artificial Lift. These include, for instance: Shell’s ” Parque das Conchas” and Petrobras’ ” Parque das Baleias” in Brazil’s Campos Basin, as well as Shell’s Perdido, Petrobras’ Cascade and Chinook, and a few other projects in deep waters in the US’ Gulf of Mexico(GOM) such as Chevron’s Big Foot.
Operating in these extreme environments will likely require deploying new production systems (e.g. with subsea boosting) and/or new generations of ESP equipment. While individual well production rates can exceed 20,000 bpd of oil, understanding of well performance is usually only marginal at the time of system design and installation. Intervention costs in these scenarios can be very high, sometimes in the US$50MM – 75MM range (per intervention). Production losses following an equipment failure can also be quite significant, especially for wells with higher production rates. Therefore, the economic success ofthese projects is closely linked to the ability to minimize the number of interventions for equipment repair and maximize production uptime. This requires not only using highly inherently reliable equipment but also having the best possible design and operational practices in place, in order to be able to actually realize the whole reliability potential of the equipment. A stated goal by some operators is to have 95% confidence that a 5 year run-life can be obtained from the ESP System, despite this very challenging operating environment.
Author:
Alhanati, F. and Trevisan, F.
Publisher:
OTC Arctic Technology Conference
Year Published:
2012
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