COMPILATION OF DOWNHOLE MEASUREMENT DATA OBTAINED BY OCEAN DRILLING PROGRAM AND PRECISE DETERMINATION OF IN-SITU PHYSICAL PROPERTIES

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Downhole measuremanets play a significant role in the Ocean Drilling Program. Due to recent improvements in the computer performance and telecommunications, downhole measurement data can be easily obtained and an intensive analysis can be carried out on an individual basis. In order to provide precise estimates of the physicalproperties of seafloor sediments, we collected as many ODP downhole datasets as possible through Internet or personally.(1) ODP geothermal data have been reestimated and revised by applying a consistent data processing; e.g. intervals of data to reduce formation temperatures are set equal for all measurements. Reprocessed heat flow data are found to be different by up to 10-20% as compared with previous results.(2) The grain thermal conductivities were estimated from measured thermal conductivities and porosities. A crossplot of grain conductivity vs. grain density revealed a slightly positive correlation for seafloor sediments obtained by ODP.(3) Porosities measured on individual samples were compared with logging porosities.(4) A semi-quantitative analysis of the Formation Micro Scanner image was carried out for ODP Leg 164 in order to get a high-resolution profile of hydrate saturation. FMS images were converted to resistivity, then to hydrate saturation using Archie's formula. The average saturation at the hydrate-bearing interval was estimated to be 5-10%.