Apparatus and methods of skin effect correction
AssigneeHalliburton Energy Services, Inc.
InventorsJunsheng Hou, Luis E. San Martin
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Abstract
Various embodiments include apparatus and methods to provide a skin-effect correction. The skin-effect correction can be based on a pre-calculated correction coefficient library. In various embodiments, a skin-effect correction procedure can be applied that only uses a single-frequency R-signal measurement. In addition, an embodiment of a skin-effect correction procedure using a single-frequency R-signal measurement can be applied whenever the quality of the data from one of the multiple frequencies normally used in a multi-frequency method is reliable. Additional apparatus, systems, and methods are disclosed.
Claims21
A method comprising:
- collecting R-signal apparent conductivity data from receivers of an induction logging tool, the R-signal data corresponding to the induction logging tool operating at a single frequency or multiple frequencies over a logging section of a borehole;
- retrieving weight coefficients from a database, each of the weight coefficients corresponding to a distance in a depth window along a length of the borehole;
- calculating a skin-effect correction apparent conductivity having a skin-effect correction by conducting a convolution filtering of conductivity values and the weight coefficients, the conductivity values derived from the R-signal data;
- and
- outputting the skin-effect correction apparent conductivity.
A non-transitory machine-readable storage device having instructions stored thereon, which, when performed by a machine, cause the machine to perform operations, the operations comprising:
- collecting R-signal apparent conductivity data from receivers of an induction logging tool, the R-signal data corresponding to the induction logging tool operating at a single frequency or multiple frequencies over a logging section of a borehole;
- retrieving weight coefficients from a database, each of the weight coefficients corresponding to a distance in a depth window along a length of the borehole;
- calculating a skin-effect correction apparent conductivity having a skin-effect correction by conducting a convolution filtering of conductivity values and the weight coefficients, the conductivity values derived from the R-signal data;
- and
- outputting the skin-effect correction apparent conductivity.
A system comprising:
- a tool having a transmitter sensor and one or two receiver sensors, the transmitter and the receiver sensors set apart from each other by a separation distance;
- a control unit operable to manage generation of transmission signals from the transmitter sensor and collection of received signals at the receiver sensors, each received signal based on one of the transmission signals;
- and
- a data processing unit, wherein the tool structure, the control unit, and the data processing unit are configured to operate to:
- collect R-signal apparent conductivity data from receivers of an induction logging tool, the R-signal data corresponding to the induction logging tool operating at a single frequency or multiple frequencies over a logging section of a borehole:
- retrieve weight coefficients from a database, each of the weight coefficients corresponding to a distance in a depth window along a length of the borehole;
- calculate a skin-effect correction apparent conductivity having a skin-effect correction by conducting a convolution filtering of conductivity values and the weight coefficients, the conductivity values derived from the R-signal data;
- and
- output the skin-effect correction apparent conductivity.
An apparatus comprising:
- a first interface arranged to collect R-signal data from a receiver of an induction logging tool, the R-signal data corresponding to the induction logging tool operated at a single frequency over a length of a borehole;
- a database arranged to store and to provide access to weight coefficients, each of the weight coefficients corresponding to a distance in the length;
- a data processing unit structured to calculate a skin-effect correction apparent conductivity having a skin-effect correction, the data processing unit operable to conduct a convolution filtering of conductivity values and the weight coefficients, the conductivity values derived from the R-signal data;
- and
- a second interface to output the skin-effect correction apparent conductivity.
Dependencies are inferred from the claim text.