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Transport and Fate of Natural Gas and Brine Escaping from a Hydrocarbon Reservoir Through a Failed Deepwater Well in the Oceanic Subsurface of the Gulf of Mexico

  • M. T. ReaganEmail author
  • G. J. Moridis
  • N. D. Keen
  • K. J. Lee
  • M. Natter
  • T. Bjerstedt
  • W. W. Shedd
Article
  • 61 Downloads

Abstract

The possibility of broaching, or the release of fluids at the seafloor due to a damaged or faulty well, is a hazard that must be assessed in the well permitting process. This paper describes a numerical simulation study of a real-life scenario where a complex, permeable sandy formation, connected to the seafloor via known chimneys/seeps, is intersected by a damaged production well that drains another deeper, gas-bearing formation. The objective of the study is to determine the transport and fate of hydrocarbon reservoir fluids (gas and brines) escaping into the sandy formation through the casing shoe of the failed well, and to determine the time it takes for these contaminants to reach the ocean floor. We conducted a detailed simulation study to represent the conditions, properties, and behavior of the system under such failure conditions, and we investigated the migration of gas and brine for a range of reservoir and chimney properties. A key conclusion is that, for such complex systems, modeling the three-dimensional geometry of the system in detail is the key to describing transport and assessing the time and magnitude of potential releases. For the system studied here, transport times range from under 2 years (highest permeabilities) to many decades, ensuring significant time to respond to potential broaching hazards. Under the conditions investigated in this study, we also determine that gas-dominated releases associated with low rates of water flow into the sandy formation are likely to cause hydrate formation that can reduce permeabilities in the colder, upper regions of the chimneys and possibly mitigate releases.

Keywords

Broaching Hydrate formation Well failure Hazard assessment Reservoir simulation 

Notes

Acknowledgements

This work was carried out under Interagency Agreement M14PG00044 between the Bureau of Ocean Energy Management and Lawrence Berkeley National Laboratory. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

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Copyright information

© This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2018

Authors and Affiliations

  • M. T. Reagan
    • 1
    Email author
  • G. J. Moridis
    • 1
    • 2
  • N. D. Keen
    • 1
  • K. J. Lee
    • 2
  • M. Natter
    • 3
  • T. Bjerstedt
    • 3
  • W. W. Shedd
    • 3
  1. 1.Energy Geosciences DivisionLawrence Berkeley National LaboratoryBerkeleyUSA
  2. 2.Department of Petroleum EngineeringTexas A&M UniversityCollege StationUSA
  3. 3.Bureau of Ocean Energy ManagementNew OrleansUSA

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