Radiation is an emotional topic. For many, the mention of the word radiation produces a strong reaction of fear. However, radiation—when treated with healthy respect—need not endanger any of those who work around it. Furthermore, radioactive logging, both neutron or gamma radiation, at the wellsite is essential to cutting the cost of exploration and improving production.
Protections from ionizing radiation are time, distance and shielding. At the wellsite certain procedures should be followed using these three principles to ensure a safe and healthy work environment.
- All rig personnel should minimize the length of time spent near a radioactive source.
- Personnel who are not needed in the proceedings should be kept out of the area when a source is being transferred from the shield to the tool.
- During the process of transferring from the shield to the tool, the hole should be covered.
- The radioactive source should be kept on the truck; and when not on the truck, it should be under visual control of the logging company personnel. If rig personnel notice an unattended source, they should tell the logging engineer about it immediately.
- If a source is found after the logging company has left, the company should be notified immediately. The source should be isolated and access to the storage area should be restricted. Exposure time should be minimized.
- During fishing operations where a logging tool containing a radioactive source is retrieved, certain steps must be taken to prevent unnecessary exposure:
- The logging engineer should consult with the rig crew on procedures.
- The fishing tool should be stopped before coming out of the hole. At this time, it should be decided how best to minimize exposure.
- Non-essential personnel should leave the rig floor.
- Drilling, rotating, pounding and milling should be avoided.
- In the case of a suspected source rupture, the principles of time, distance, and shielding become doubly important:
- Restrict any area which might be contaminated.
- If rescue operations are necessary, rescuers should be protected from prolonged exposure. Radiation exposure should be spread among a large crew for short periods rather than allowing one person to receive a large amount of exposure.
- Protection from contamination can be provided through the means of protective layering (e.g., wearing several layers of clothing and gloves). A scarf over the mouth will help prevent inhalation or ingestion of radioactive material.
- People who may have been contaminated should be isolated.
- Anyone who has been working around the rig should be checked for contamination.
- Eating, drinking, and smoking are all prohibited.
- If it is discovered that someone has been contaminated, the person should shower immediately. Body folds and hairy areas should be scrubbed for at least 15 minutes. All clothing, everything from the hard hat right down to the boots, should be bagged and labeled.
- NORM or Naturally Occurring Radiation is another source of radiation in the oilfield.