PROBLEMS AND FUTURE WORK

Although we have shown that the IR camera can be a valuable tool for rapid gas hydrate identification, there are several issues that need to be addressed in order to make the transition from a mainly qualitative tool to a more quantitative method.

  1. Core handling times and catwalk temperature need to be monitored more carefully than was possible during Leg 201. The times to be measured include the wireline trip time and the time it takes to extract the core liner from the barrel, move it to the catwalk, and run the thermal scan. Whereas we have illustrated that scan times did not affect the core liner temperature distribution, the wireline trip does, and it has been suggested that core handling procedures can significantly affect the core temperatures (M. Storms and T. Bronk, unpubl. data [N2]). This is particularly important for hydrate and microbiological sampling, which are very temperature sensitive. Additionally, examining air temperatures at the time of scanning (rather than depending on the bridge's 4-hr measurements) would conclusively confirm a lack of sampling bias associated with air temperature.
  2. A track is needed to run the camera along the core at constant speed. This will greatly facilitate depth calculation and correlation of the temperature data to other physical property data. The use of a track might also reduce problems with focusing and with reflections caused by the curvature of the core liner. If the camera were run across the core at a constant angle relative to the core, possible reflections would at least remain constant as well.
  3. The use of the image analysis software needs to be standardized to avoid user-dependent biases during data analysis. It is also integral to increase the efficiency of the analyses.
  4. Emissivity differences of different sediment types need to be taken into consideration. This will be especially important for temperature scans of split-core surfaces to examine hydrate distribution, since emissivity differences of various sediment types will significantly influence the absolute temperature readings of the camera.

Despite the need for improvement, thermal imaging has proven to be a successful method for gas hydrate identification in sediment cores. This method has great potential for becoming a valuable tool for gas hydrate identification and quantification in the future.

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