Reeves Wireline Technologies Limited

Weatherford Technology Holdings, LLC

Said Assous

Peter Adrian Spencer Elkington

Peter Adrian Elkington

James Anthony Whetton

Joanne Tudge

Laurence Linnett

Mark Bacciarelli

A method can include energizing a tube with a longitudinally extending magnetic field generated inside the tube, using a magnetic field-detecting logging tool to generate magnetic flux signals generated inside the tube externally of the material of the tube wall resulting from such energizing at circumferential locations on the inner surface of the tube and at distances along the tube, iteratively using a model of the relationship between the generated magnetic flux signals and the thickness of the tube wall to derive a thickness profile of the tube wall by using (i) the magnetic permeability of the tube material deduced from the magnetic flux signals and (ii) a defect-free flux parameter representative of any non-linearity between the magnetic field strength and flux density in the tube, the iteration including using the model to calculate an initial approximate wall thickness profile using an initial estimate of the defect-free flux parameter.

Method of and apparatus for determining variations in wall thickness in ferromagnetic tubes

In a method to transform logs, an acoustic logging tool inserted into a borehole includes a source and an array of receiver stations. Each station includes a receiver spaced along the tool from the source by successively greater distances. In the method, the source emits energy (I) to cause the propagation towards the stations of plural signals exhibiting paths characteristic of first and second respective modes and (II) to stimulate a receiver of each station to generate an output signal per station that indicates the signal packets and represents the modes in combination with one another. In the method, the output signals are transformed into transformed signals containing phase/amplitude information of each mode. The phase/amplitude are linked by an operator to the slowness and attenuation of the mode and the transmitter-receiver distance of the station. The phase/amplitude are used to extract slowness and attenuation information for each mode.

Methods of and apparatuses for transforming acoustic log signals

In acoustic well logging, for each inversion depths of a well at which logging of data occurs, acoustic log signals representative of waveforms received at acoustic receivers are processed in a frequency domain to derive field dispersion curve(s). A neural net is operated to generate formation shear slowness value(s) from the curve(s), and resulting signal(s) indicative of shear slowness values are saved, transmitted, plotted, printed or processed. An apparatus for carrying out the method includes a logging tool having at least one activatable acoustic wave source; spaced and acoustically isolated therefrom in the logging tool an array of acoustic detectors that on the detection of acoustic wave energy generate electrical or electronic log signal(s) characteristic of acoustic energy waves detected by the acoustic detector(s); and at least one processing device associated with or forming part of the logging tool for processing the log signal(s).

Method of and apparatus for carrying out acoustic well logging

Disclosed herein is method of computing formation attributes from acoustic measurements in a borehole. The acoustic measurements can be made by operating an acoustic source at multiple frequencies to excite the formation and operating receivers at multiple, longitudinally spaced receiver stations to receive acoustic energy from the formation. The method can include: deriving phase data from the spectrum of received acoustic signals; unwrapping phase information of the phase spectrum data; determining two or more values of difference of phase between acoustic signals at each of a range of frequencies each based on a single generated signal received at two or more pairs of adjacent said receiver stations; generating a value of slope of phase difference values; and in any case of slope ambiguity, unwrapping phase difference information and deriving a dominant slope, at each frequency, from which slowness of the acoustic signal in the formation can be derived.

Methods of and apparatuses for improving log data

A method and a resistivity image logging tool connected or connectable to one or more processing devices process geological log data to construct missing information from destroyed or occluded parts using cues from observed data. The geological log data signals can be generated through use of the logging tool having one or more electrodes interacting with a formation intersected by a borehole. The processing involves the steps of: in respect of one or more data dimensions associated with missing values in a log data set, decomposing the signal into a plurality of morphological components; and morphologically reconstructing the signal such that missing values are estimated.

Geological log data processing methods and apparatuses

A method of processing borehole log data to create one or more image logs involve modelling the log data as components of an image in the form i(x, y)=l(x, y)&#xd7;r(x, y) (1), in which i(x, y) is an image representative of the log data, l(x, y) denotes an illumination value of the image at two-dimensional spatial co-ordinates x, y, and r(x, y) denotes a surface reflectance value at the co-ordinates x, y. Equation (1) is transformed to a logarithmic domain, and a Fourier transform is obtained of the resulting logarithmic domain expression to obtain a Fourier domain expression. The Fourier domain expression is high-pass filtered, and an inverse Fourier transform is obtained of the resulting filtered Fourier domain expression. An exponential operation is performed on the result of inverse Fourier transform to obtain a filtered image model expression. Values of the filtered image model expression are mapped to respective color values across the range of the filtered image model expression values. The mapped color values can then be displayed, printed, saved and/or transmitted as one or more image logs.

Borehole log data processing methods

A method of processing geological log data to construct missing information from destroyed or occluded parts using cues from observed data comprises the steps of: a. in respect of one or more data dimensions associated with missing values in a log data set, decomposing the signal into a plurality of morphological components; and b. morphologically reconstructing the signal such that missing values are estimated.

A method of detecting an edge of a geological characteristic in a borehole comprises, in respect of an image log of a length of a borehole, carrying out the steps of a gradient-based edge detection method, a phase congruence-based edge detection method or a combination of such methods as preliminary, pre-processing stages. Subsequent steps of the method may include operating a relatively computationally simple process to identify sinusoids among detected edge features; and a relatively computationally complex process for parameterizing the thus-identified sinusoids.

Methods of and apparatuses for identifying geological characteristics in boreholes

A method of processing borehole log data to create one or more image logs involve modeling the log data as components of an image in the form i(x, y)=l(x, y)&#xd7;r(x, y) (1), in which i(x, y) is an image representative of the log data, l(x, y) denotes an illumination value of the image at two-dimensional spatial co-ordinates x, y, and r(x, y) denotes a surface reflectance value at the co-ordinates x, y. Equation (1) is transformed to a logarithmic domain, and a Fourier transform is obtained of the resulting logarithmic domain expression to obtain a Fourier domain expression. The Fourier domain expression is high-pass filtered, and an inverse Fourier transform is obtained of the resulting filtered Fourier domain expression. An exponential operation is performed on the result of inverse Fourier transform to obtain a filtered image model expression. Values of the filtered image model expression are mapped to respective color values across the range of the filtered image model expression values. The mapped color values can then be displayed, printed, saved and/or transmitted as one or more image logs.

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Nottingham, United Kingdom

Said Assous