The quantification of all aspects of the geosciences is creating a growing demand for accurate measurements of such quantities as physical properties, mechanical state parameters, and chemical compositions. ODP holes are becoming increasingly recognized as important probes of environmental conditions as well as records of lithology. Various techniques are available for measurements of the desired quantities in ODP holes, but most of these have proved to be poor in sections of moderately consolidated sediments, which comprise an ever increasing percentage of footage drilled. At the JOI/USSAC workshop on Physical Properties in ODP, this concern was addressed and a recommendation a made to develop the Navidrill/Geoprops concept. In this concept, a 3 3/4" hole is drilled 5 m ahead of the main bit with a mud-motor drive core bit and barrel. This Navidrill assembly can be withdrawn on a sand line and Geoprops probe, an internally recording system with packers and an array of sensors, can be quickly placed in the small hole. A conservative initial design envisages measurements of temperature, pore pressure. permeability, stress orientation and pore fluid composition, but other measurements could be added if the concept is successful. Before construction of the Geoprops probe, a feasibility study is necessary to insure the need for and suitability of such an approach, to outline the scientific and engineering constraints, and to develop a general layout. This award will support such a study.
