Chevron Research Company

Dresser Industries, Inc.

Chevron Research & Technology Company

Other

Jorg A Angehrn

Carroll W Chapman

Peter Graebner

Swan A Sie

Anthony P Howells

Raman Viswanathan

Charles F Magnani

Wade M Johnson, Jr

Vernon E Groeschel

Ronald E Diederich

Anthony M Dienglewicz

Dennis J Fischer

The flow of bubbles in a borehole within an active well is determined by using data from a borehole televiewer. A known discontinuous material is introduced into the borehole at a known distance from the borehole televiewer, and the elapsed time is determined between introduction and detection of the discontinuous material by the borehole televiewer.

Method for fluid identification and evaluation within wellbores using

A borehole televiewer is modified to provide an improved signal-to-noise ratio by utilizing a series of receivers arranged in a planar array configuration with respect to a centrally located transmitting transducer. The array covers at least a 90.degree. quadrant of the tool, extending approximately 45.degree. on either side of the transducer to allow the receivers to capture all primarily reflected signals, both the specular component as well as the vertical and horizontal components of the scattered reflections. The signal-to-noise ratio is further enhanced by the use of a noise-dependent timing means, as well as signal conditioning and detection circuits for each of the receivers in the array.

Method and apparatus for ultrasonic scanning of a borehole having

A method is disclosed for using data from a borehole televiewer in an active well to determine fluid properties. That method involves determining the wall effects from the data, and factoring out the wall effects from the data to determine the fluid properties.

A method and means for determining the amount of stretch in a well logging cable is disclosed. An optical fiber is run into a well with a logging cable and looped back to the surface. A second optical fiber of nominal length is maintained on the surface. A source of monochromatic light is passed through both fibers and recombined. As the well logging tool is raised and lowered in the wellbore, the number of interference fringes passing a fixed point is determined. The change in length of the optical fiber and, therefore, the cable will be equal to 1/2 the number of interference fringes passing a fixed point times the wavelength of light used. A precise determination of vertical location can then be made when this information is combined with information from a surface mounted odometer or encoder. This information further allows a precise determination of interval bulk density or other formation parameters in which it is important to know the depth of a tool.

Interferometric means and method for accurate determination of

A system is disclosed for creating a three-dimensional image of data obtained from scanning a borehole wall with an acoustic transducer. Each scan produces an orientation pulse and a series of signals, including a fire pulse and echo signals. The system uses the transit times of the echo signals to modulate the geometry of the three-dimensional image, and uses the amplitudes of the echo signals to control the gray scale shading of the image. In one embodiment, a counting means keeps track of the angular position of the transducer, a ramp generating means produces a ramp voltage proportional to the elapsed time since the fire pulse, a sine table means and a sine conversion means produce a sine signal proportional in amplitude to the ramp voltage, a cosine table means and a cosine conversion means produce a cosine signal porportional in amplitude to the ramp voltage, and a monitoring means displays points on the monitoring means when the echo signals are received. The points are moved radially from the center of a circle in a direction controlled by the sine and cosine signals, and the intensities of the points are proportional to the amplitudes of the echo signals.

Three-dimensional borehole televiewer display

A method and apparatus for determining the vertical location of a logging tool in a wellbore is disclosed. An electrical signal is transmitted through a conductor in a well logging cable and a second conductor in the surface. Change in length of the well logging cable is determined by monitoring phase changes in the signals from the first and second conductors.

Electrical phase measurement means and method for accurate determination

The response characteristics of a combination of hole-centered electric logging tools in a variety of borehole conditions can be obtained by means of impedance values as entries of a matrix resulting from measurements over a series of depth increments, utilizing an array of M electrode assemblies of equal incremental spacing positioned on a rigid mandrel. While the array is substantially stationary within the borehole, currents from ech electrode are emitted independently, one at a time, allowing the impedance matrix to be formed by the principle of linear superposition in terms of voltage and voltage difference measurements between adjacent electrodes; the impedance matrix is inverted and used to generate a set of tool responses, which when properly compared to a set of tool responses previously generated by computer simulation and addressable by sets of borehole parameters and calibration factors, allows the corresponding borehole conditions to be deduced from the measured data.

Method of interpreting impedance distribution of an earth formation

The present invention is an improved mud excluder fitted around a rotating acoustic transducer of a borehole televiewer to exclude mud from the borehole televiewer. This mud excluder has:

Flexible mud excluder for borehole televiewer

The response characteristics of a combination of hole-centered electric logging tools in a variety of borehole conditions can be obtained by means of impedance values as entries of a matrix resulting from measurements over a series of depth increments, utilizing an array of 2M-1 electrode assemblies of equal incremental spacing positioned on a rigid mandrel. While the array moves continuously along the borehole, current is continuously emitted from the centrally located current electrode allowing the impedance matrix to be formed by the principle of linear superposition in terms of voltage and voltage difference measurements between adjacent electrodes. The impedance matrix is inverted and used to generate a set of tool responses, which when properly compared to a set of tool responses previously generated by computer simulation and addressable by sets of borehole parameters and calibration factors, allows the corresponding borehole conditions to be deduced from the measured data.

The response characteristics of a combination of hole-centered electric logging tools in a variety of borehole conditions can be obtained by means of impedance values as entries of a matrix resulting from measurements over a series of depth increments, utilizing an array of 2M-1 electrode assemblies of equal incremental spacing positioned on a rigid mandrel. While the array moves continuously along the borehole, current is continuously emitted from the centrally located current electrode allowing the impedance matrix to be formed by the principle of linear superposition in terms of voltage and voltage difference measurements between adjacent electrodes.

Methd of logging an earth formation penetrated by a borehole to provide

The response characteristics of a combination of hole-centered electric logging tools in a variety of borehole conditions can be obtained by means of impedance values as entries of a matrix resulting from measurements over a series of depth increments, utilizing an array of M electrode assemblies of equal incremental spacing positioned on a rigid mandrel. While the array moves continuously along the borehole, currents are emitted independently and sequentially from first one and then the other of current electrodes located at the shallow and deep ends of the array, allowing the impedance matrix to be formed by the principle of linear superposition in terms of voltage and voltage difference measurements between adjacent electrodes. The impedance matrix is inverted and used to generate a set of tool responses, which when properly compared to a set of tool responses previously generated by computer simulation and addressable by sets of borehole parameters and calibration factors, allows the corresponding borehole conditions to be deduced from the measured data.

Method of logging an earth formation penetrated by a borehole to provide

The response characteristics of a combination of hole-centered electric logging tools in a variety of borehole conditions can be obtained by means of impedance values as entries of a matrix resulting from measurements over a series of depth increments, utilizing an array of M electrode assemblies of equal incremental spacing positioned on a rigid mandrel. While the array is substantially stationary within the borehole, currents from each electrode are emitted independently, one at a time, allowing the impedance matrix to be formed by the principle of linear superposition in terms of voltage and voltage difference measurements between adjacent electrodes.

An improved well logging technique is provided for more accurately deriving and correlating a plurality of measurements made during a single traversal of a logging instrument through subsurface formations. In one exemplary embodiment, methods and apparatus are provided for deriving a more accurate and precise measurement of depth at which real-time logging measurements are made, and in particular for correcting anomalies occurring in the depth indication from cable stretch, yo-yo of the sonde in the borehole and the like. The more accurate and precise depth measurement is then utilized for generating well logging measurements on a depth-dependent basis, deriving at least some of such measurements in digital form and alternately transmitting to the surface digital and analog representations of such measurements. Furthermore, methods and apparatus are provided for deriving measurements of subsurface earth formation from a plurality of logging instruments combined in a single tool, wherein such measurements are made during a single pass through a borehole with the resultant measurement data correlatively merged, recorded and displayed.

Growing community of inventors

Brea, CA, United States of America

Jorg A Angehrn