Schlumberger Technology Corporation

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Isabelle M Dubourg

Ollivier Faivre

Gilles Rouault

Roel Van Os

Michel V Berard

Dominique Dion

Carlos Maeso

Luca Ortenzi

Pierre Eisenmann

Daniel Quesada

Yoshinobu Jinzaki

A method for determining a fracture aperture of a fracture aperture in a wellbore comprises measuring a resistivity of the wellbore with a downhole tool in a wellbore for obtaining an image of the wellbore. Based on the image, the method detects fractures in the wellbore, and calculates a fracture aperture of the detected fracture according to a predetermined model of the wellbore set up based on hypothesis relative to the configuration of the wellbore. Then, the method estimates a correction to the predetermined model when at least one of the hypothesis is not met, and determines an uncertainty range for the fracture aperture also using a measured parameter.

Method and apparatus for determining a fracture aperture in a wellbore

Methods and systems for determining a standoff between a downhole tool and a geological formation are provided. The standoff may be determined using a standoff measurement system that includes an electrode component, one or more electronics components, one or more transformers, and one or more processor units. When the standoff is expected to be no more than a first distance, a first measurement can be made where both originating and resulting electrical signals are induced at the electrode component. When the standoff is expected to be no less than a second distance, a second measurement can be made where an originating electrical signal is induced at one of the transformers while a resulting electrical signal is induced at the electrode component.

Methods and systems for determining standoff between a downhole tool and a geological formation

An apparatus for determining the resistivity of formation surrounding a borehole comprising:

Method and apparatus for measuring resistivity of formations

The invention concerns a method for determining the resistivity in a formation crossed by a cased well, in which one carries out at least one resistivity log in the cased well and one uses the results of at least one resistivity log in the non-cased well, carried out in the same well previously, in order to, in at least one zone () of the formation in which the resistivity has not changed between the cased and non-cased condition, deduce the value of a geometric factor k conditioning the resistivity and for determining, by means of said geometric factor k and the log in the cased well, the resistivity in at least one zone () different to the calibration zone, in which the resistivity has varied between the non-cased condition and the cased condition.

Method and device for determining the resistivity in a geological formation crossed by a cased well

Process for determining the resistivity (Rt) of a formation () surrounding a well () equipped with a casing () consisting of several casing segments () with an overlapping part (), and cement () in the overlapping part (), Application particularly to oil exploration.

Process for determining the resistivity of a formation through which a well equipped with a casing passes

The invention relates to a method of correcting the measurements of a pressure gauge for the influence of temperature transients. In a preferred embodiment, a correction term is added to the pressure value measured at an instant t, the correction term A.sub.O [T(t+.tau.)-T(t)] being proportional to the difference between the temperature T(t+.tau.) measured after a time interval of duration .tau. has elapsed from instant t, and the temperature T(t) at instant t. The invention is applicable to measurements in oil wells.

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Chilly Mazarin, France

Isabelle M Dubourg