Schlumberger Technology Corporation

Other

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Schlumberger Oilfield Assistance Limited

Eni S.p.a.-Agip Division

Emmanuel Legendre

Reza Taherian

Jean P Seydoux

Alexandre Abellan

Thilo Michael Brill

Gerald N Minerbo

Jian Yang

Martin G Luling

Fabienne Legendre

Jacques R Tabanou

Richard A Rosthal

Thomas D Barber

Edward Nichols

Qiming Li

Pabitra N Sen

Jean-Luc Le Calvez

Barbara I Anderson

Dean M Homan

Henri-Pierre Valero

Smaine Zeroug

Benoit G Froelich

Alain M Dumont

Richard Bloemenkamp

Mark A Fredette

Arnaud Jarrot

Koji Ito

Ollivier Faivre

Yann Dufour

Benoit Deville

Gaelle Jannin

Philippe F Salamitou

Jean-Claude Trouiller

Robert C Smith

Pierre Mouget

Nicolas Renoux

Jean-Luc Garcia

Libo Yang

Sergiy Kryukov

Takeo Fujihara

Laurent Jammes

Henri Budan

Georgi Kutiev

Mark Kuchenbecker

Eric Grandgirard

Pascal Rothnemer

Mathieu Tarrius

Sofiane Ellouz

Eunmi Choi

Benoît Froelich

Maria Teresa Galli

Mauro Gonfalini

Patrizio Gossenberg

Carlos Jeronimo Maeso

A method can include acquiring data from a borehole imaging tool disposed in a borehole in a formation where the borehole includes electrically insulating oil-based fluid introduced into the borehole as a drilling lubricant; determining, based on the data, electrically insulating oil-based fluid impeditivity and a reference formation impeditivity via a circuit model that includes series and parallel terms; and detecting a location of a fracture in the formation based on a change in current flow from the tool through the electrically insulating oil-based fluid and into the formation by determining an effective formation impeditivity based on at least a portion of the data for the location and by comparing the effective formation impeditivity to the reference formation impeditivity.

Fracture characterization while drilling

A method includes emitting, with one or more sensors of a downhole tool disposed in a borehole, an excitation signal. The method also includes detecting, with the one or more sensors, a returned signal resulting from an interaction of the excitation signal with the borehole. The method further includes estimating a noise of the returned signal. The method also includes quantifying a probability that the estimated noise is not a white noise of the borehole. The method further includes identifying drill cuttings in a predetermined location of the borehole based on said quantification.

Downhole detection of cuttings

Apparatus and methods operable to determine between a wall of a wellbore penetrating in a subterranean formation and a resistivity tool disposed in the wellbore. One such method includes using an apparent impedance function depending on a frequency variable and a plurality of unknown parameters, at least one of the unknown parameters depending on a formation impedance of the subterranean formation. The method also includes applying a voltage, at each of a plurality of frequency values, between electrodes of a resistivity tool that is disposed in the wellbore. The method also includes measuring, across the electrodes, a plurality of apparent impedance values, each corresponding to a different one of the frequency values. The method still further includes determining the unknown parameters based on the frequency values and the apparent impedance values, and estimating the standoff distance based on an expression that includes at least one of the unknown parameters.

Determining standoff between a wall of a wellbore and a tool disposed in the wellbore

Systems and methods are provided for estimating the tool center position of a downhole tool, the geometry of the borehole, and/or a mud parameter based on sensor measurements from the downhole tool, even when the downhole tool center is moving over time. At least one sensor may obtain a set of measurements that relates to distance-to-borehole in a borehole at a number of azimuths. A processor may estimate a set of values defining borehole boundary and a set of positions of a center of the downhole tool in the borehole, at least in part by estimating the borehole boundary based on the set of measurements assuming a previously estimated position of the center of the downhole tool is true and estimating the position of the center of the downhole tool based on the set of measurements assuming a previously estimated borehole boundary is true, and iterating at least until convergence.

Systems and methods for determining tool center, borehole boundary, and/or mud parameter

Apparatus and methods operable to determine a resistivity of a subterranean formation surrounding a wellbore. One such method includes using an apparent impedance function depending on a frequency variable and a plurality of unknown parameters, at least one of the unknown parameters depending on a formation impedance of the subterranean formation. The method also includes applying a voltage, at each of a plurality of frequency values, between electrodes of a resistivity tool that is disposed in the wellbore. The method also includes measuring, across the electrodes, a plurality of apparent impedance values, each corresponding to a different one of the frequency values. The method still further includes determining the unknown parameters based on the frequency values and the apparent impedance values, and estimating the formation resistivity based on an expression that includes at least one of the unknown parameters.

Method and apparatus for determining resistivity of a formation

Systems and methods for estimating standoff and/or caliper in a wellbore for oil-based mud drilling are provided. The systems include a sensor having a primary electrode and at least two secondary electrodes, and an electronics subsystem having a controller and a processor for driving the system and correlating current measurements with standoff and/or caliper. The electrodes are positioned relative to one another such that there is a distinct flow of current between the primary electrode and each secondary electrode. In operation, a single excitation frequency is applied to the primary electrode and a simultaneous measurement of current flowing between the primary electrode and each secondary electrode is obtained. Standoff is estimated from the measurements. The estimations can be independent of formation properties when an appropriate excitation frequency is used.

System and methods for measuring borehole caliper in oil-based mud

The present disclosure introduces an apparatus for downhole measurement of a formation resistivity. The apparatus includes a probe having a button electrode, a first guard electrode insulated from the button electrode, a second guard electrode insulated from the first guard electrode, and a return electrode positioned external to the second guard electrode. The apparatus also includes an electrical source for setting a voltage drop between the second guard electrode and the return electrode, a first impedance (R) electrically coupled between the button electrode and the second guard electrode, and a second impedance (R) electrically coupled between the first guard electrode and the second guard electrode.

Dual-guard imager probe

A method to obtain gain-corrected measurements. A measurement tool having one or more arrays is provided, wherein the arrays include two co-located triaxial transmitters and two co-located triaxial receivers. Measurements are obtained using the transmitters and the receivers. Impedance matrices are formed from the obtained measurements and the impedance matrices are combined to provide gain-corrected measurements. The apparatus may alternatively be a while-drilling logging tool having one or more arrays, wherein each array comprises a transmitter, a receiver, and a buck, and wherein the signal received by the receiver is subtracted from the signal received by the buck or vice versa. A slotted shield may be incorporated into either embodiment of the tool. The slots may form one or more island elements. A material is disposed in the slots. The islands and shield body have complementary tapered sides that confine the islands within the shield body.

Gain-corrected measurements

Systems, methods, and devices for compensating for environmental conditions on electromagnetic measurements are provided. For example, a downhole logging tool may include a first transmitter coil, a second transmitter coil, and a first receiver coil. The first transmitter coil may provide a first magnetic signal in a wellbore having a conductive casing. The second transmitter coil may provide a second magnetic signal in the wellbore. The first receiver may obtain a first measurement relating to the first magnetic signal and a second measurement relating to the second magnetic signal. The first receiver coil may be near enough to the first transmitter coil and the second transmitter coil to obtain measurements predominantly in the near field eddy current regime. A ratio of the first measurement and the second measurement may cancel environmental dependencies of the first receiver coil.

Measurement compensation using multiple electromagnetic transmitters

A technique facilitates the accumulation and analysis of data related to a subterranean formation. An arrangement of different types of sensors is mounted on a collar utilized in accumulating data on the subterranean formation. The sensors are operable in combination to improve the image quality of data obtained with respect to the subterranean formation. Certain applications utilize an arrangement of sensors comprising at least one of each of an electromagnetic sensor and an ultrasonic pulse-echo transducer. A stabilizer or stabilizers may be used to precisely orient and position the sensors within a wellbore.

Subterranean imager tool system and methodology

A disclosed example method involves receiving a first signal transmitted into a reservoir from a production installation in a formation at a wellsite, and determining an apparent resistance of the reservoir based on the first signal. A distance between a fluid extraction tool and a fluid distribution is determined based on the apparent resistance.

Methods and apparatus to detect fluid distributions

The apparatus employs the remote field eddy-current (RFEC) inspection technique to electromagnetically measure physical parameters of a metallic pipe. RFEC devices inserted into and displaced along a cylindrical pipes may be used to measure the ratio of pipe thickness to electromagnetic skin-depth and thus allow for the non-invasive detection of flaws or metal loss. Typically these RFEC thickness measurements exhibit a so-called double-indication of flaws, an undesired artifact due to a double-peaked geometrical sensitivity function of the device. The method describes a means by which this double indication artifact may be removed by an appropriate processing of RFEC measurements performed by an apparatus specifically designed for this purpose. The invention is particularly well designed for applications in the oilfield industry.

Method and apparatus for removal of the double indication of defects in remote eddy current inspection of pipes

Techniques involve determining the frequency-dependent dielectric permittivity spectrum of a rock sample. Determining the frequency-dependent dielectric permittivity may involve defining a series of electromagnetic measurement data having at least a measurement at a frequency from which a substantially frequency-independent value of dielectric permittivity &#x2208;can be obtained. The electromagnetic measurement data also includes measurements at different frequencies from which values for frequency-dependent dielectric permittivity &#x2208;(f) can be obtained. Using these measurements, the frequency-dependent spectrum of the sample may be determined.

Methods for determining dielectric permittivity spectrum of underground rock formations

A technique utilizes the acquisition of data from desired subterranean regions via a logging system. The logging system is constructed for use in a wellbore and comprises a transmitter module having a transmitter antenna. Additionally, the logging system utilizes a receiver module spaced from the transmitter module and having a receiver antenna. The transmitter antenna and the receiver antenna are oriented to enable sensitivity in desired directions, such as ahead of the logging system.

Look ahead logging system

The present disclosure relates to a method to determine the phase of a signal when transmitter and receiver circuits use separate clocks. A discrepancy between the separate clocks is determined, as is a correction factor between the separate clocks. The phase is determined using a measured time of arrival of the signal, the determined discrepancy, and the determined correction factor. A drift factor and an expected start time of a pulse sequence may be used to determine the discrepancy. A start time of a pulse within the pulse sequence is determined and used to determine the correction factor. The method works by either absolute synchronization of the separate clocks, or by making the measurements independent of clock synchronization.

Measuring the phase of received signals

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Sevres, France

Emmanuel Legendre