[ RadSafe ] Well logging Sources
Cowie, Michael I
michael.cowie at aramco.com
Wed Jun 20 02:14:26 CDT 2018
Saudi Aramco: Company General Use
Radioactive sources used in well logging activities on occasion become stuck, and sometimes are abandoned in the well. The current accepted practice appears to be along the lines:
•The source must be immobilized and sealed in place with a dyed-red cement plug with a minimum length 200 feet.
•A deflection metallic object shall be placed by Radiation Service Provider on the top of the cement plug.
•Where there are no perforations in the well the lateral distance between the well containing the abandoned radioactive source and any subsequently drilled well or adjacent drilled holes shall be minimum 15 feet.
•Perforating operations shall not be conducted at minimum of 200 feet in any direction of the radioactive sources.
•A well which contains an abandoned radioactive source shall be marked with an identification plaque.
•The identification plaque shall serve as a visual warning to any future reentering the hole that a radioactive source has been abandoned in place in the well.
•The identification plaque shall be permanently attached to the wellhead after the abandonment of the radioactive sources is completed.
•An identification plaque constructed of long lasting material such as stainless steel must be mounted at the surface of the well The identification plaque shall be at least seven (7) inches square and 1/8th off an inch thick, with the following information:
oThe word “CAUTION”
oThe radiation symbol
oThe date the source was abandoned
oThe well name and number
oThe contractor name who owned the radioactive sources
oAn identification of the sealed source(s) by radionuclide, quantity and serial number
oThe depth of the source and the depth to the top of the plug
oThe phrase, “DO NOT ENTER THIS WELL BEFORE CONTACTING XYZ "
Every reasonable effort shall be made to recover the radioactive sources and prevent its abandonment.
But does anyone know the basis for the 200 feet? Also is anyone aware of studies/investigations into the integrity of sealed radioactive sources left in such environments? It would also seem to be prudent to verify the integrity of the cement barrier on occasion, but I cannot find anywhere which states this.
When trying to research this topic, I became aware that there appears to be a confusion - the abandonment seems to relate to the well rather than the radioactive source/s, albeit it is initiated due to the presence of the stuck sources. Would be interested in any information/thoughts as I can see this being an area for scrutiny in the future.
email has been classified as Saudi Aramco: Company General Use by Cowie, Michael I
on Wednesday, June 20, 2018 10:14:25 AM.
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