| 摘要 |
Process for determining the resistivity (Rt) of a formation ( 9 ) surrounding a well ( 10 ) equipped with a casing ( 11 ) consisting of several casing segments ( 11. i , 11. s) with an overlapping part ( 1 ), and cement ( 3 ) in the overlapping part ( 1 ), in which a current is injected into the casing ( 11 ) to cause a leakage current (Ifor) into a area ( 8 ) of the formation ( 9 ) offset from the overlapping part ( 1 ), the leakage current (Ifor) in the measurement area ( 8 ) is determined and is used to deduce the measured resistivity (Rm) of the formation, a current is injected into the casing ( 11 ) to cause a current leakage (Icem) in the cement ( 3 ) of the overlapping part ( 1 ), the leakage current (Icem) in the cement ( 3 ) in the overlapping part ( 1 ) is determined, and is used to deduce the measured resistivity (Rcem) of the cement ( 3 ), the measured resistivity (Rm) of the formation ( 9 ) is corrected using a factor to take account of the measured resistivity (Rcem) of the cement ( 3 ) to obtain the resistivity (Rt) of the formation ( 9 ). Application particularly to oil exploration.
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