Halliburton Energy Services, Inc.

Yi Jing Fan

Hsu-Hsiang Wu

Li Pan

Jin Ma

Clint Paul Lozinsky

Weixin Dong

Systems and methods for smoothing a resistivity log are disclosed. An azimuthal resistivity tool measures azimuthal impedances at multiple azimuthal angles around a wellbore axis at each depth. It is determined whether the drill string was in a drilling mode or a sliding mode at the depth. If the drill string was in the drilling mode, a co-axial component and a lateral component are determined based in part on the azimuthal impedances associated with the depth and the lateral component is stored. If the drill string was in the sliding mode, a second co-axial component is determined based in part on at least one of the plurality of azimuthal impedances and a previously stored lateral component. The resistivity log is plotted from resistivities determined from the first and second co-axial components at each depth.

Resistivity logging in sliding mode

A system and a method for evaluating a subterranean earth formation include a logging tool locatable in a wellbore dispose in the formation. The logging tool may include a transmitter antenna and a single receiver antenna. The transmitter antenna is configured to transmit a first electromagnetic signal into the subterranean earth formation. The system further includes a processor and a non-transitory memory device. The memory device includes instructions that cause the processor to control a current and a voltage sourced to the transmitter antenna, receive, via the single receiver antenna, a second electromagnetic signal emitted by the subterranean earth formation in response to receiving the first electromagnetic signal, and determine a resistivity of the subterranean earth formation based on the second electromagnetic signal.

Resistivity determination from one transmitter and one receiver antennas

Systems and methods of the present disclosure relate to calibration of resistivity logging tool. A method to calibrate a resistivity logging tool comprises disposing the resistivity logging tool into a formation; acquiring a signal at each logging point with the resistivity logging tool; assuming a formation model for a first set of continuous logging points in the formation; inverting all of the signals for unknown model parameters of the formation model, wherein the formation model is the same for all of the continuous logging points in the first set; assigning at least one calibration coefficient to each type of signal, wherein the calibration coefficients are the same for the first set; and building an unknown vector that includes the unknown model parameters and the calibration coefficients, to calibrate the resistivity logging tool.

Accurate and cost-effective inversion-based auto calibration methods for resistivity logging tools

A method and system for identifying a blind spot in one or more decoupled measurements. The method may comprise disposing an electromagnetic well measurement system into a wellbore. The electromagnetic well measurement system comprise an electromagnetic transmitter and a plurality of electromagnetic receivers. The method may further comprise transmitting electromagnetic fields into a formation with the electromagnetic transmitter, measuring the electromagnetic fields with the plurality of electromagnetic receivers as one or more measurements at one or more depths in the wellbore, decoupling the one or more measurements to form decoupled measurements, identifying if a blind spot is in the decoupled measurements, and performing an inversion with the decoupled measurements.

Compound signal for logging while drilling resistivity inversion

Systems and methods of the present disclosure relate to calibration of a resistivity tool. A method for in-situ calibration of a resistivity logging tool, comprises transmitting signals with transmitters of the resistivity logging tool; measuring voltages at two or more receivers located at different distances to the transmitters of the resistivity logging tool; decoupling two or more sets of multi-component tensors at two or more receivers based on the measured voltages; calculating a ratio signal from two or more sets of multi-component tensors; obtaining an apparent resistivity based on the ratio signal; simulating a dipole response tensor at the first receiver based on the apparent resistivity; comparing the first set of multi-component tensor with the dipole response tensor to acquire an in-situ calibration factor; and applying the in-situ calibration factor to multi-components for an inversion input.

In-situ calibration for multi-component signals

Systems and methods of the present disclosure relate to calibration of a resistivity tool. A calibration method comprises deploying a transmitter in a known formation with a known resistivity property with a physical tilted angle &#x3b8; relative to a longitudinal axis of the tool; deploying receivers in the known formation, wherein a physical tilted angle of a first receiver is &#x3b8; relative to the longitudinal axis of the tool, and wherein a physical tilted angle of a second receiver is &#x2212;&#x3b8;, relative to the longitudinal axis of the tool; transmitting signals with the transmitter and measuring the signals at the receivers; combining measurements at two receivers with respect to a transmitter signal in the known formation; producing synthetic responses of the tool in the known formation using forward modeling; and calculating an effective tilted angle &#x3b8;' from real measurements and the synthetic responses.

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Singapore, Singapore

Yi Jing Fan