A geophysical logging contractor is a small part of an exploration or mining development team. The team would likely include a drilling contractor(s), rig geologists, staff geologists, fieldies, logistics, and camp logistics.
But if you are drilling deep boreholes or in unstable ground which requires geophysical logging off a rig, failure of a geophysical logging contractor can soon mount up in additional cost related to standby of other contractors. So it makes sense to have confidence in your logging contractor:
Contracted equipment:
• Safety: So important in today’s world. Everybody has a right to go to work, earn their money and return at the end of the day or shift to their families. What safety management systems are in place? What is their safety record? Is there a positive safety culture?
• Depth capability meets contract requirements. This is not only winch capacity but also the temperature and pressure rating of their probes.
• Probe list meets contract requirements – but how many logging runs are required to record all contracted logging data? Modern logging systems can “stack” different probes together which can significantly reduce logging time and hence rig standby time. For example, temperature data may be a requirement. One logging contractor may have a separate probe requiring a separate run in the borehole whereas another logging contractor can add the temperature probe to another logging run stack – hence one less logging run in the borehole.
• Is their logging probes fit for the contract conditions? For example, some contractors state they own neutron probes for porosity. More often than not the neutron probes are single spaced detectors. Accurate porosity measurements require dual spaced detectors so the ratio between the long and the short spaced detectors can be used for the quantitive porosity calculation.
• Equipment backup, maintenance and redundancy: Logging equipment is electronic and/or mechanical. It can fail! Does your logging contractor have spare equipment on call. Ask if the spare equipment is being used elsewhere – it may not be on call for you! An owner operator company may offer the lowest rates but it could cost in the long run if equipment fails. Does the logging contractor have regular maintenance schedules for their equipment? For example, logging in saline groundwater conditions means there should be increased vigilance on the conditions of the wireline, particularly the cablehead. Maintenance of the cablehead should be increased under such conditions – you don’t want your probe to fall off due to corrosion!
• Logging data is all about repeatability or precision. Does their logging data repeat or are they generating random numbers? Ask for their quality control procedures pre, during and post project equipment checks.
• What is the experience of their personnel? Experience counts and can make small issues disappear rather than building into bigger issues. What is their staff turnover? (Always a good question as good people stay with well-run companies)
• Head office backup: Are the loggers all alone or are they backed up from their local office/head office?
• Does the logging contractor have the correct and appropriate state licenses in place? A stuck radioactive probe is bad enough but then to find the company is acting unlicensed (company and personnel) – well the risk and clean-up is all yours. Remember a logger needs to have a current state radiation license to transport a radioactive source as well as use one. Logging companies using neutron AmBe sources will almost certainly need an approved security management and transport plan to comply with state legislation.