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|1. (WO2004029663) DEVICE AND PROCESS FOR DETERMINATION OF THE RESISTIVITY OF A FORMATION SURROUNDING A CASED BOREHOLE|
|Applicants:||SERVICES PETROLIERS SCHLUMBERGER
SCHLUMBERGER TECHNOLOGY B.V.
SCHLUMBERGER HOLDINGS LIMITED
SCHLUMBERGER CANADA LIMITED
PETROLEUM RESEARCH & DEVELOPMENT N.V.
SCHLUMBERGER OVERSEAS S.A.
SCHLUMBERGER OILFIELD ASSISTANCE LIMITED
SCHLUMBERGER SURENCO S.A.
SCHLUMBERGER SERVICES LIMITED
SCHLUMBERGER SEACO INC.
|Title:||DEVICE AND PROCESS FOR DETERMINATION OF THE RESISTIVITY OF A FORMATION SURROUNDING A CASED BOREHOLE|
Body (22) for measuring the resistivity of a formation (9) surrounding a well (10) equipped with a lining (11), comprising: a body (23) of a probe (22), a set of three primary voltage measurement electrodes (ea, eb, ec), an upper electrode (ea) and a lower electrode (ec) and a central electrode (eb), two electrodes (Inl, In2), an upper current injection electrode (Inl) and a lower current injection electrode (In2) arranged on each side of the set of primary electrodes, characterized in that it also comprises, two secondary voltage measurement electrodes (24, 26) arranged on each side of the set of primary electrodes (ea, eb, ec), and between the two current injection electrodes (Inl, In2), the spacing between a secondary electrode (24, 26) and the closest primary end electrode (ea, ec) being more than 1.5 times the spacing between the primary electrodes (ea, eb, ec).