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Volume 6 Issue 1

May 2011

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HOUSTON SPOTLIGHT

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Analysis of Deepwater Currents.
The offshore oil industry has collected current profile measurements from floating production facilities (FPFs) and mobile drilling units (MODUs) in the Gulf of Mexico since 2005. This program has been conducted under mandates issued by MMS (now BOEMRE) in the form of Notices to Lessees (NTLs). Data have been collected from over 30 FPFs and more than 50 MODUs, providing roughly 200 years of current profile measurements. The data are reported in near real-time to the National Data Buoy Center (NDBC) where they receive initial quality checks and are quickly archived and made publically available through the NDBC website (http://www.ndbc.noaa.gov/maps/ADCP_WestGulf.shtml).

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Example of Google Earth interface that will be developed by Woods Hole Group as part of the DeepStar Project.

Although NDBC’s near real-time processing and quality checking of the data provides useful products to assist operations in the Gulf of Mexico, it is not intended to provide the level of quality assurance that structural engineers and oceanographers need to develop design criteria and to better understand the complicated and vigorous ocean circulation features in the Gulf of Mexico. Further, inspections of the archived data revealed that some measurements, especially near-bottom data, are absent. Some of the measurements, especially near-surface data, also contain systemic and systematic errors, such as erroneous measurement locations, instrument headings, etc., which needed to be addressed.

A second major and equally important set of current data in the deepwater Gulf of Mexico has been collected through series of focused deepwater current measurement programs. These programs were begun in the late 1990s and have been funded through the MMS Environmental Studies Program (now BOEMRE). The measurement programs have advanced from east to west in the northern Gulf of Mexico, and have focused on understanding important physical processes, such as the Loop Current, Loop Current Eddies, and Topographic Rossby Waves. A variety of techniques have been employed, including current meter moorings, satellite data analysis, drifter studies (surface and subsurface), hydrographic sections, and geostrophic current estimates using inverted echo sounder (IES) technology. These data are thoroughly quality controlled and have been analyzed and reported in MMS Technical Reports and refereed literature. All physical oceanographic data collected in the Environmental Studies have been archived at the National Oceanographic Data Center (NODC), where they are publically accessible. As with the NTL data at NDBC, the data require supplemental processing for use by industry engineers.

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Woods Hole Group designed ADCP Launch and Recovery System.

The combination of industry sponsored NTL data sets and MMS Environmental Studies data sets is perhaps the largest archive of current data in any regional ocean basin. However, due to the data being held at two different locations (NDBC and NODC), in significantly different formats, and need for supplemental data quality assurance, industry engineers find it difficult at present to take advantage of this incredible resource.
The DeepStar joint industry technology development project decided to apply some of its resources to meet its members' deepwater business needs to deliver increased production and reserves. DeepStar provides a forum to execute deepwater technology development projects and leverage the financial and technical resources of the deepwater industry. Participating companies presently include: Anadarko, BP, Chevron, ConocoPhillips, Maersk Oil, Marathon, Nexen, Petrobras, Statoil and Total. See http://www.deepstar.org/ for more information.

DeepStar initiated a project in 2011 that is being conducted by the Woods Hole Group to improve the usefulness of both the NTL and MMS Environmental Studies data. The objectives of this project are to:

  • Retrieve the measurements taken under the auspices of the MMS NTL and Environmental Studies
  • Perform a thorough review/consistency check of that data
  • Archive the fully QA/QC’d measurements in a searchable database
  • Screen the measurements to identify energetic events and document those events for future study
  • Use the measurements to refine the present conceptual model of the north-central Gulf of Mexico circulation

To date, available data sets have been gathered and are being prepared for quality checking. The first step is to ensure that available data are indeed in house. For the NTL data this will entail checking time lines of data downloaded from the NDBC website for each NDBC station against an independent record of the activity of mobile drilling units and floating production facilities to identify any possible gaps. Likewise, time lines of the Environmental Studies Data obtained from NODC will be compared to time lines presented in the MMS Technical Reports.

A variety of quality checks will be undertaken to ensure that the resulting data archive includes only data whose accuracy can be reasonably assured. This project is scheduled to be completed by the end of this year.

Submitted By:
Dave
David Szabo, M.S.
Houston Office Manager/Senior Oceanographer

Our contact information is:
Woods Hole Group - Houston
10615 Shadow Wood Drive, Suite 100
Houston, TX 77043
P: (713) 468-5075

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