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September 2011 Issue

National Data Buoy Center Sees Mooring Failures Fall by a Third
A number of mooring improvements made by the National Data Buoy Center (NDBC) have decreased its mooring failures by 38 percent since 2009, the center announced in August.

Mooring designs used by the NDBC include all-chain, semitaut, taut, inverse catenary and low-load compliant. The moorings are deployed in water depths between 10 and 6,000 meters.

NDBC said in recent years it has made a number of mooring improvements, such as better modeling tools, designs, forensics capabilities, handling equipment, quality assurance and deployment procedures.

Following these changes, mooring failures dropped by a third, from 39 failures in 2009 to 26 failures in 2010. In the first six months of 2011, the center was on track to continue improving its record, with a projected 24 failures for the year.

The center said the lower number of failures has saved money and improved data availability.

"Mooring reliability is extremely important for NDBC mission success," the center said in a press release. "Mooring failures are costly due to the replacement cost of the mooring as well as the additional cost of recovering the adrift buoy."

For more information, visit www.ndbc.noaa.gov.

Knudsen Engineering Tests Pinger SBP System in Vermont
Knudsen Engineering Ltd. (Perth, Canada) has put its new 15-kilohertz Pinger sub-bottom profiling (SBP) system through testing on Lake Champlain, Vermont, the company said in July. Tests were completed with the support of Middlebury College and the college's RV Baldwin.

The Pinger features chirp transmission and a large-aperture receiver. It uses polyvinylidene fluoride technology, which Knudsen said provides higher directivity while cutting weight.

Knudsen said another benefit of the Pinger receive array is its wide bandwidth, which allows the same receive array to be used simultaneously for multiple frequencies.

The company said it designed the Pinger to be very portable and lightweight, making it suited for small boats and shallow-water applications that have been problematic with traditional SBP systems because of transmission pulse ringing. The Pinger operated in water as shallow as 1.5 meters during the demonstration on Lake Champlain, Knudsen said.

SonarWiz 5 SBP software from Chesapeake Technology Inc. (Mountain View, California) was used to process and display the data collected with the Pinger.

Knudsen said the results from the Pinger were "exceptionally good, with very high-resolution mapping of the layers and bedrock as well as depth of penetration." For more information, visit www.knudsenengineering.com.

Partrac Voyager II Benthic Flume Acquires Seabed Data for Study
A Voyager II benthic flume from Partrac Ltd. (Glasgow, Scotland) was recently used in an investigation of nutrient and sediment resuspension events in the North Sea, results of which were published in the July in Estuarine and Coastal Shelf Science.

The paper, "In-Situ Measurements of Resuspension in the North Sea," was a collaborative project between the U.K. Centre for Environment, Fisheries and Aquaculture Science, the National Oceanography Centre (Southampton, England) Portsmouth University, Southampton University and Partrac.

The flume was deployed at three sites in the North Sea, an area where the nutrient budget does not add up, apparently due to missing terms. The work was directed at measuring the input of nutrients into the water column due to resuspension of the bottom sediments. The study focused on the collection of data on seabed entrainment and nutrient exchange parameters at depths up to 83 meters.

Previously, Partrac said, the only means of collecting this data was through collection of cores or manipulative laboratory studies, each of which has limitations.

Partrac said the Voyager II's ability to measure these fluxes at the seabed on undisturbed sediments represented a substantial technological advance that offers scientific improvements.

The results are the first in-situ data of this type to be reported at such depths, Partrac said, adding that the study provided valuable insights into the magnitudes of resuspension and the flux rates for nutrients under both median and storm conditions. For more information, visit www.partrac.com.

Baker Hughes Unveils Rotary Sidewall Coring Tool
Baker Hughes (Houston, Texas) has commercialized its MaxCOR sidewall coring service, a large-diameter rotary sidewall coring tool designed to recover 1.5-inch-diameter cores in extreme environments.

MaxCOR, which operates at up to 25,000 pounds per square inch and at temperatures up to 400° F, is designed to retrieve 60 samples in a single run. Baker Hughes said MaxCOR acquires more than three times the volume of core in about the same amount of rig time it takes to deploy standard one-inch rotary sidewall coring tools.

The larger core volumes from MaxCOR provide more accurate measurements of reservoir attributes such as porosity, permeability and geomechanical properties, the company said, enabling operators to more accurately evaluate reservoirs and maximize hydrocarbon recovery with the least amount of rig time.

Baker Hughes said MaxCOR is the only coring technology capable of recovering large-diameter samples after a well is drilled. It uses a direct-drive electric motor in place of a traditional hydraulic motor to power the bit, providing maximum power transfer efficiency under all load and borehole temperatures, the company said.

Scott Schmidt, president of drilling and evaluation for Baker Hughes, said that in addition to deepwater work in Brazil, MaxCOR was used successfully in a number of U.S. shale plays, including the Barnett and the Eagle Ford shale basins."The service is invaluable for providing the high-quality core samples operators need to more accurately characterize complex deepwater and shale reservoirs."

For more information, visit www.bakerhughes.com.



2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2011:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC


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