The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 19, 2005
Filed:
Mar. 29, 2001
Philip Cheung, Montesson, FR;
Andrew Hayman, Voisins-le-Bretonneux, FR;
Dennis Pittman, rue Claude Monet, FR;
Abdurrahman Sezginer, Los Gatos, CA (US);
Philip Cheung, Montesson, FR;
Andrew Hayman, Voisins-le-Bretonneux, FR;
Dennis Pittman, rue Claude Monet, FR;
Abdurrahman Sezginer, Los Gatos, CA (US);
Schlumberger Technology Corporation, Sugar Land, TX (US);
Abstract
The present invention relates to a method of investigating the wall () of a borehole in a geological formation by means of two injectors () with a potential V being applied between them and in measuring the potential difference δV between two electrically isolated measurement electrodes () situated between the two injectors () and spaced apart from the formation by an insulating layer (), in which the resistivity of the formation is obtained from the measured values of δV, V and I, with corrections being made for the effects due to the nature and the thickness of the insulating layer (). In a first variant these corrections are based on a correction factor obtained from curves of K=Rt.I/δV as a function of the impedance V/I of the injector. In a second variant these corrections are obtained by estimating the current Iactually injected into the formation while taking account of leakage current I, and calculating the resistivity of the formation from the equation (I). The invention also provides an investigation device enabling the values of Iand/or Ito be estimated.