Naturally occurring radioactive material contamination detection means
AssigneeTexaco Inc.
InventorsThomas Marion Williams, Irwin Ray Supernaw
Life of this patent
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Abstract
Radioactive contamination on tubing is detected as the tubing is withdrawn from a wellbore. The tubing is moved past a detector located on the wellhead, preferably through an annular shaped detector, and means responsive to the detected level of radiation exceeding predetermined limits activate both an alarm to gain the operator's attention and means to apply indicia to the contaminated tubing.
Claims10
A method for detecting radioactive scale deposited on the wall of well tubing as the tubing is removed from a well borehole, comprising the steps of:
- placing a gamma ray detector producing output signals indicative of the intensity and energy of gamma rays and shaped and adapted to be placed on the wellhead and in close proximity to the point where well tubing exits the borehole as said tubing is being pulled from a well;
- connecting to said detector, means responsive to said output signals, for indicating when the intensity level of said signals exceeds a predetermined level;
- and
- monitoring the intensity level of said output signals with said means for indicating when said level exceeds a predetermined level and providing an alarm indication when said predetermined level is exceeded.
Apparatus for detecting the presence of radioactive material on the surface of tubing as the tubing is withdrawn through the wellhead from a well borehole, comprising:
- a gamma ray detector shaped to be located on the wellhead and in close proximity to the tubing as it is removed from the well borehole, said detector generating output signals indicative of the intensity level and energy of gamma rays detected;
- means responsive to said output signals and wherein said output signal levels are correlated to an exposure rate for detecting radiation exposure levels exceeding a predetermined safety limit;
- and
- alarm means for generating an alarm signal and for identifying said tubing causing said output signal levels exceeding a predetermined exposure safety limit, said alarm means being controlled by said means responsive to said output signals.
Dependencies are inferred from the claim text.