Pathfinder Energy Services, Inc.

Halliburton Energy Services, Inc.

Smith International, Inc.

Samuel Mark Haugland

Teruhiko Hagiwara

Martin Dale Paulk

Martin Paulk

The present invention provides non-transitory computer-readable media and systems are suitable for evaluating a dynamic wellbore azimuth and inclination measurement based on measurements acquired by a downhole tool capable of acquiring accelerometer (gravity) and magnetic field measurements representative of the earth's gravitational and magnetic fields. These non-transitory computer-readable media and systems can also be used for evaluating static inclination and azimuth measurements. These non-transitory computer-readable media and systems comprising the present invention provide an improvement over the prior art for their function and address many shortcomings of prior art.

System and method for continuous wellbore surveying

A method for determining a shear wave velocity of a subterranean formation from a leaky shear wave arrival is disclosed. Standoff measurements are utilized to indicate the presence of leaky shear wave arrivals in the received waveforms. In one exemplary embodiment, leaky shear waves are indicated when the measured standoff distance is less than a predetermined threshold. The invention may provide for a direct determination of shear wave velocity in acoustically slow formations, thereby potentially improving accuracy as compared to prior art estimation techniques. The invention may further provide for improved power efficiency.

Shear wave velocity determination using evanescent shear wave arrivals

A method for estimating an azimuthal dependence of a parameter of a borehole using logging sensor measurements acquired as a function of azimuth of the logging sensors is provided. The method includes acquiring at least one logging sensor measurement and a corresponding azimuth from a downhole tool. The method further includes processing a convolution of the logging sensor measurement and corresponding azimuth with a predetermined filter to determine convolved logging sensor data for at least one azimuthal position. Certain embodiments of this invention may be advantageously utilized in LWD imaging applications to provide for superior image resolution and noise rejection as compared to prior art imaging techniques.

Enhanced measurement of azimuthal dependence of subterranean parameters with filters and/or discretely sampled data

A method for determining a borehole geometry parameter vector and/or lateral tool displacement vectors in a borehole is provided. The method includes acquiring at least one set of standoff measurements at a corresponding time. The method also includes processing a system of equations to determine the parameter vector and/or the lateral displacement vector(s). The system of equations may include variables representative of the parameter vector, the lateral tool displacement vector(s), and the standoff measurements. Exemplary embodiments of this invention advantageously enable the borehole parameter vector and/or the lateral displacement vector to be determined substantially contemporaneously.

Estimation of borehole geometry parameters and lateral tool displacements

Briefly, a method of estimating electrical parameters of an earth formation employs a simplified model of a measurement tool or device in transforming or normalizing data measured by the measurement tool. Electrical parameters of the earth formation, such as conductivity or dielectric constant, for example, may be estimated based on the normalized data.

Method of estimating electrical parameters of an earth formation with a simplified measurement device model

A method for determining a borehole azimuth in a borehole is disclosed. In one exemplary embodiment, the method includes acquiring at least one standoff measurement and a tool azimuth measurement at substantially the same time. Such measurements are then processed, along with a lateral displacement vector of the downhole tool upon which the sensors are deployed in the borehole, to determine the borehole azimuth. The computed borehole azimuths may be advantageously correlated with logging sensor data to form a borehole image, for example, by convolving the correlated logging sensor data with a window function. As such, exemplary embodiments of this invention may provide for superior image resolution and noise rejection as compared to prior art LWD imaging techniques.

Determination of borehole azimuth and the azimuthal dependence of borehole parameters

A method for determining a formation shear wave velocity for a subterranean formation includes propagating a multi-pole acoustic signal in a borehole using an acoustic transmitter and receiving an acoustic waveform from the multi-pole acoustic signal at one or more receivers deployed at the same circumferential position as the transmitter. The method further includes processing the acoustic waveform to determine a borehole guided wave velocity and processing the borehole guided wave velocity to determine the shear wave velocity of the subterranean formation. Isolation, suppression or enhancement of any particular harmonics of the acoustic signal is not required.

Shear wave velocity determination using circumferentially aligned transmitter and receiver elements

A method for determining a formation shear wave velocity for a subterranean formation is provided. The method includes propagating a multi-pole acoustic signal in a borehole using an acoustic transmitter and receiving an acoustic waveform from the multi-pole acoustic signal at at least one receiver. The method further includes processing the acoustic waveform to determine a borehole guided wave velocity and processing the borehole guided wave velocity to determine the shear wave velocity of the subterranean formation. Isolation, suppression or enhancement of any particular harmonics of the acoustic signal is not required.

Shear wave velocity determination using multi-pole wave

A method for estimating an azimuthal dependence of a parameter of a borehole using logging sensor measurements acquired as a function of azimuth of the logging sensors is provided. The method includes acquiring at least one logging sensor measurement and a corresponding azimuth from a downhole tool. The method further includes processing a convolution of the logging sensor measurement and corresponding azimuth with a predetermined window function to determine convolved logging sensor data for at least one azimuthal position. Certain embodiments of this invention may be advantageously utilized in LWD imaging applications to provide for superior image resolution and noise rejection as compared to prior art imaging techniques.

Enhanced measurement of azimuthal dependence of subterranean parameters

Method and apparatus are provided for adjusting electromagnetic well logging data for effects of frequency dispersion. In exemplary embodiments, a model is provided for estimating an electrical property of an earth formation as a function of frequency. The model is derived, for each particular volume of interest, based on measured data obtained by employing a plurality of interrogation frequencies. Measured data may include electrical properties of the volume of interest such as conductivity and dielectric constant. The model predicts the measurements expected to be obtained by a tool employing a selected interrogation frequency, including frequencies for which no measured data are available. In one embodiment, the model may be used to adjust measured data for effects of frequency dispersion to correspond to a selected interrogation frequency, allowing the adjusted data to be more effectively correlated to logging data obtained by a different type of tool employing a different interrogation frequency.

Adjustment for frequency dispersion effects in electromagnetic logging data

A method of compensating for tool motion is disclosed. In one embodiment, the method includes passing a logging tool through a borehole, obtaining a series of tool response measurements, and obtaining a series of tool position measurements associated with the tool response measurements. The tool position measurements preferably indicate the distance between the tool axis and the borehole axis. The tool position measurements are preferably examined to determine if the tool was moving while the tool was making measurements. For measurements made while the tool was moving, the measurement time interval is preferably divided into subintervals each having a corresponding tool position. A formation property (such as resistivity) is estimated, and the expected tool response for each tool position is calculated. The expected tool responses are combined to form a model tool response, that is, the tool response that might be expected for a tool in motion. The model tool response is then compared to the measured tool response. The estimate of the formation property is adjusted and the process is repeated until the model tool response is substantially equal to the measured tool response.

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Houston, TX, United States of America

Samuel Mark Haugland