Schlumberger Technology Corporation

Services Petroliers Schlumberger

Peter T Wu

Pierre Henri Campanac

Thomas D Barber

Alain M Dumont

Mark T Frey

Bikash Kumar Sinha

Jacques R Tabanou

Gerald N Minerbo

David Linton Johnson

Gong Li Wang

Hanming Wang

James G L Thompson

Brian Oliver Clark

Dean M Homan

Jahir A Pabon

Aria Abubakar

Qiming Li

Shu-Kong Chang

Jan Smits

Andrew Hawthorn

Tom R Bratton

David Furse Allen

Anshuman Sinha

Cheng Bing Liu

Helen Xiaoyan Zhong

Samer Alatrach

David J Scheibner

Dong Weixin

Victor E Grijalva

Charles A Johnson

Thomas Daniel Barber

A method for making downhole electromagnetic logging measurements of a subterranean formation is disclosed. An electromagnetic logging tool is rotated in a subterranean wellbore. The tool includes a transmitter axially spaced apart from a receiver. The transmitter may include an axial transmitting antenna and at least one transverse transmitting antenna and the receiver may include an axial receiving antenna and at least one transverse receiving antenna. The transmitting antennas transmit corresponding electromagnetic waves into the subterranean wellbore. The receiving antennas receive corresponding voltage measurements which are processed to compute harmonic voltage coefficients. Ratios of the selected harmonic voltage coefficients are processed to compute gain compensated, azimuthally invariant measurement quantities.

Compensated azimuthally invariant electromagnetic logging measurements

A two-step inversion method for computing multi-layer subterranean formation properties includes processing gain compensated electromagnetic measurement quantities using a first inversion to compute a corresponding set of borehole corrected gain compensated measurement quantities. The first inversion includes a mathematical model of the tool and the borehole in a uniform, anisotropic formation. The set of borehole corrected gain compensated measurement quantities are then processed using a second inversion to compute multi-layer anisotropic formation properties. The second inversion includes a 1D inversion employing a point dipole model and a multi-layer formation model.

Methods for inverting electromagnetic logging measurements

Described herein is a method including acquiring a set of transimpedance coupling voltages, between different antenna components of different axes of a transmitting station transmitting into a formation and different antenna components of different axes of a receiving station receiving from the formation, using an induction tool undergoing random movement during the acquisition. Fourier coefficients for the set of transimpedance coupling voltages are determined using a least square process. A mean tool eccentering azimuthal angle and an apparent formation azimuthal angle are estimated as a function of the Fourier coefficients. Compensated measurements are computed as a function of the Fourier coefficients. An inversion loop receives as input the compensated measurements, the estimated mean tool eccentering azimuthal angle, and the estimated apparent formation azimuth, and outputs final parameters as a function thereof.

Methods of estimating borehole and formation properties using an electromagnetic induction logging tool having random tool decenter positions during data acquisition

A method for making gain compensated electromagnetic logging measurements of a subterranean formation includes rotating an electromagnetic logging tool in a subterranean wellbore. The logging tool includes a transmitter having at least one transmitting antenna axially spaced apart from a receiver having at least one receiving antenna. Electromagnetic waves are transmitted into the subterranean wellbore using the at least one transmitting antenna. Voltage measurements corresponding to the transmitted electromagnetic waves are received at the receiving antenna. The voltage measurements are processed to compute real and imaginary directional resistivity measurement quantities.

Real and imaginary components of electromagnetic logging measurements

A method for drilling a wellbore includes drilling a well along a path substantially along a bedding direction of a selected subsurface formation having at least one substantially vertical fracture therein. A direction of the at least one substantially vertical fracture is determined with respect to a direction of the prior to drilling therethrough. A direction of the path is adjusted so that the well will intersect the at least one substantially vertical fracture substantially perpendicularly to the direction.

Method for steering a well path perpendicular to vertical fractures for enhanced production efficiency

A method for determining resistivity of subsurface formations includes generating an initial model of the formations from multiaxial electromagnetic transimpedance measurements, the model comprising values of vertical resistivity, horizontal resistivity, crossbed dip, crossbed azimuth, and bedding dip and azimuth. Expected measurements generated from the initial model measurements are decomposed into ordinary and extraordinary components. The actual tool measurements are compared to the summation of the expected decomposed measurement components. The initial model is adjusted, the expected decomposed components are recalculated and the foregoing are repeated until the difference between the actual tool measurements and the summation of the expected decomposed components falls below a selected threshold.

Multiaxial well logging instrument response in dipping and crossbedded formations

A method for logging a formation or sample includes obtaining a plurality of multiaxial conductivity measurements from the formation or sample. A horizontal resistivity measurement, a dip measurement and a dip azimuth measurement are derived from the plurality of multiaxial conductivity measurements. A sharp vertical resistivity measurement is derived from a subset of the plurality of multiaxial conductivity measurements.

Adaptive inversion for vertical resistivity logs from multiaxial induction measurements

A method for making downhole electromagnetic logging measurements includes using an electromagnetic measurement tool to acquire the measurements while rotating in a subterranean wellbore. Received electromagnetic waves are processed to obtain harmonic voltage coefficients, ratios of which are in turn further processed to compute gain compensated measurement quantities. The gain compensated measurement quantities are further processed to compute at least one of an apparent formation azimuth of the formation through which the wellbore traverses, an apparent tool eccentering azimuth, and an eccentering distance of the logging tool in the wellbore.

Method for estimating formation dip azimuth and eccentering azimuth

A method for characterizing fractures traversing a wellbore includes input to a computer multiaxial electromagnetic induction measurements corresponding to measurements made along two mutually orthogonal magnetic dipole moment axes perpendicular to an axis of the wellbore. The measurements correspond to at least one receiver spacing from a transmitter. The measurements represent induced voltage in a receiver having a same dipole moment direction as a dipole moment direction of a transmitter. A first derivative with respect to wellbore depth of the multiaxial electromagnetic induction measurements is calculated. At least one peak and an amplitude thereof of the first derivatives is calculated. The peak and the amplitude are used to determine a location and an aperture of at least one fracture traversing the wellbore.

Method for formation fracture characterization in highly inclined wells using multiaxial induction well logging instruments

A method for identifying fractures from measurements made by a multi-axial electromagnetic induction tool in a wellbore traversing subsurface formations includes determining a value of a fracture orientation indicator from in line components of the multi-axial electromagnetic induction measurements made transverse to a tool axis, and parallel to the tool axis. The tool axis is substantially parallel to a bedding plane of the subsurface formations. A value of a vertical fracture indicator is determined using the in line components of the multi-axial electromagnetic induction measurements made transverse to the tool axis, and parallel to the tool axis.

Fracture detection method using multi-axial induction tool

A method for determining existence of a fracture in a formation surrounding a wellbore drilled through subsurface rock formations includes calculating vertical resistivity, horizontal resistivity, apparent formation dip, apparent formation azimuth and axial resistivity for a plurality of longitudinal instrument spacings using measurements from a triaxial induction well logging instrument disposed in the formation. A spread in the axial resistivity values is determined and the axial resistivity spread threshold therefrom. Fracture indicator values and fracture orientation values are calculated from transverse components of the triaxial induction measurements. Presence of a fracture is indicated when at least one of the fracture indicator value exceeds a selected threshold, the axial resistivity spread exceeds the spread threshold and when the apparent formation dip exceeds a selected threshold.

Real-time fracture detection and fracture orientation estimation using tri-axial induction measurements

The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more tri-axial antennas is provided and used to obtain azimuthally sensitive data. Borehole correction is performed on the obtained data and a ZD-inversion is performed on the borehole corrected data for all antenna spacing groups. A formation indicator flag is determined and, depending on the determined formation indicator flag, a 1D-axial inversion and/or a 1D-radial inversion is performed over selected zones, or neither is performed. The best ZD-inversion results are selected and the 1D-axial inversion results and/or the 1D-radial inversion results, if any, are combined with the selected best ZD-inversion results to form a composite inversion result. The formation property of the subsurface formation is determined using the composite inversion result.

Real-time formation anisotropy and dip evaluation using tri-axial induction measurements

A method for estimating fracture aperture from multi-axial electromagnetic induction measurements made in a wellbore includes determining a fracture indicator and a fracture orientation indicator. The value of the fracture indicator is determined from components of the measurements made transverse to the tool axis. A relationship between the value of the fracture indicator and the fracture aperture for the subsurface formation is determined by estimating the fracture indicator using a plurality of values of fracture aperture and a resistivity of drilling fluid in the wellbore over a background formation with estimated horizontal resistivity and vertical resistivity. The fracture aperture is determined using the determined fracture indicator and the determined relationship.

Fracture aperture estimation using multi-axial induction tool

A method for correcting formation properties due to effects of a borehole is disclosed. The method includes obtaining voltage measurements using a logging tool disposed in a borehole penetrating a subsurface formation. The method further includes using a processor to: determine a tensor for the formation using the voltage measurement. For a given set of parameters, the processor determines, based upon the voltage measurements, a parameter value for each parameter in a subset of the set of parameters. The method further uses the processor to compute a borehole-inclusive modeled tensor that includes the effects of the borehole using the parameter values, optimize the parameter values using the determined tensor and the borehole-inclusive tensor, compute an optimized tensor using the optimized parameter values, compute a borehole corrected tensor using the optimized tensor, and determine at least one borehole corrected formation property using at least one of the borehole corrected tensor or the optimized parameter values.

Determining borehole corrected formation properties

A method for estimating formation porosity and lithology on a real time basis during a logging while drilling operation using measured values of formation attenuation attributes for compression and/or shear.

Growing community of inventors

Missouri City, TX, United States of America

Peter T Wu