Method and apparatus for reducing radioactive hazards in well boreholes
First Claim
1. A logging tool adapted to be used in a well borehole for obtaining measurements by irradiation from a radioactive source, comprising:
- (a) an elongate logging tool body adapted to be lowered into a well borehole;
(b) a radioactive source in said body for forming radiation enabling a logging activity to be conducted in the well borehole, said source having a half life of less than about 10 days and comprising a radioactive isotope of iodine or gold; and
(c) wherein said radioactive source is carried within an enclosure means.
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Abstract
In logging operations in a well borehole where difficulties arise in retrieval of the logging apparatus, drilling through the logging tool is sometimes necessary. This disclosure sets forth a radioactive source material which permits this remedial step. The radioactive source material is either a short half life radioactive isotope or is in fluid form. In fluid form, it is purged out of the sonde by means of a motor controller triggered into operation to operate a piston and cylinder pump arrangement. The outlet from the cylinder is through a flow line and check valve. The purged radioactive source material is then flushed to the bottom of the well borehole and is ideally forced into a selected formation for disposal, thereby safely removing the radioactive materials from the sonde to permit destruction of the sonde.
22 Citations
24 Claims
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1. A logging tool adapted to be used in a well borehole for obtaining measurements by irradiation from a radioactive source, comprising:
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(a) an elongate logging tool body adapted to be lowered into a well borehole; (b) a radioactive source in said body for forming radiation enabling a logging activity to be conducted in the well borehole, said source having a half life of less than about 10 days and comprising a radioactive isotope of iodine or gold; and (c) wherein said radioactive source is carried within an enclosure means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A logging tool adapted to be used in a well borehole for obtaining measurements by irradiation from a radioactive source, comprising:
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(a) and elongate logging tool body adapted to be lowered into a well borehole; (b) a radioactive source in said body for forming radiation enabling a logging activity to be conducted in the well borehole; and (c) wherein said radioactive source is formed of a fluid radioactive isotope within an enclosure means. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of logging a well borehole which comprises the steps of:
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(a) placing a radioactive source in a sonde to be lowered into a well borehole; (b) lowering the sonde into the well borehole to conduct logging operations therein wherein the logging operations are subject to failure preventing retrieval of the sonde; (c) sensing a failure in the logging operations wherein retrieval of the sonde is not permitted; and (d) purging the radioactive source from the sonde. - View Dependent Claims (18, 19, 20, 21, 22, 24)
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23. The method of claim 23 wherein the source is an isotope having a half life of less than about 10 days.
Specification