The objective of the project is to design, to develop and to test various borehole logging sondes with a slimline diameter of 40 mm and to combine them with an integrated logging system in order to reduce drilling related costs in exploration.
Various borehole-sonds with a slimline diameter and with the capability of being combined with one common master tool have been designed and produced as prototypes.
The tools will be connected via the master tool for a PC-based recording unit with installed software, so that only one surface unit is needed for various tools.
For technical reasons and different requirements to the conditions of the drillholes, the system will always be used with one specific tool connected to the master tool. This also allows easier handling.
Due to technical problems with single tools and interfacing problems with the master tool and the surface unit, the development needed more time and effort than originally scheduled.
Therefore the field tests have to be carried out after the ending of the project parallel to tomographic measurements in a lead zinc mine within another project.
There is a strong demand for such a system, so that the chances for practical applications are very promising.
The logging tools will be constructed with highly integrated electronic modules to reduce the cost of reproduction and to improve tool reliability, resulting in a low cost logging system that can be used for measurements in the exploration of raw materials. This will be of benefit for small and medium contractors and mining companies in Europe because they can refer to a cost efficient, multisensor logging system, which is well suited for cooperated marketing of the European project partners. The logging system will be designed for shallow holes (maximum 800 m).
Due to the complexity of the data, gathered by the spectral gamma tool, the televiewer tool and the radar tool, software support is required to enable quality control of the sensors and specify final technical values of the sensors.
The work programme starts with a definition phase to define and carefully describe the functions and the specifications of the borehole logging system. Contemporaneously, the proposed sensors will be modeled and tested and the partners will evaluate the possibility of the tool realization under the given constraints and check if the desired performance will meet the practical requirements definition phase.
Electronics development and mechanical tool design is followed by prototype tests in the laboratory. The first version of the processing and interpretation software will be applied to check the results. Based on the experience of the test measurements, the tools will be improved.
After all of the prototype tools are ready for first field measurements, a measurement and completion phase will be entered.
Important milestones will be reached after the definition phase and again after completion of the prototypes.
A gamma tool for the detection of the natural gamma radiation of minerals, a gamma-gamma tool for density measurements and a resistivity tool will be developed by DMT (30 months). These standard tools are necessary to gain basic information of the investigated geological formations. A radar system will be integrated into the logging system to record reflections from minerals in the surrounding area of the borehole and for tomographic surveys. The personal computer based recording unit with installed logging software will also be made by DMT.
2 logging tools will be miniaturized: a spectral gamma tool for the identification of minerals and the acoustic televiewer for the description of the mineral distribution.
Work on the spectral gamma tool is based on an innovative design currently under development for oil well formation evaluation but will be tailored to the identification of minerals of strategic importance to the European Community. The chosen technique is gamma ray spectrometry by neutron interrogation.
The borehole televiewer is a logging tool for ultrasonic imaging of the borehole wall. The resolution of the resulting images is in the millimeter range and provides valuable information (eg hole geometry, the presence and orientation of fractures, faults and unconformities). The data flow of this tool is significant, and techniques of data reduction and tool miniaturization are the efforts of this development.
Funding SchemeCSC - Cost-sharing contracts
2628 CK Delft
OX11 0RA Didcot