Mud angle determination by equalizing the response of buttons for electromagnetic imager tools

An electromagnetic imaging system for reducing mud effect while imaging formations surrounding a wellbore, the system comprising:

• an electromagnetic imager tool having one or more measurement units that have azimuthal sensitivity;
• one or more processors;
• and
• at least one computer-readable storage medium having stored therein instructions which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
• receiving a plurality of tool measurements made through the one or more measurement units while the electromagnetic imager tool is operating to log a wellbore in a formation, the plurality of tool measurements including contributions from both mud and formation;
• applying one or more mud effect removal techniques to the plurality of tool measurements across a plurality of mud angle estimates to generate a plurality of mud effect removed quantities for the one or more measurement units across the plurality of mud angle estimates;
• averaging the plurality of mud effect removed quantities for the one or more measurement units to generate averaged mud effect removed quantities at each of the plurality of mud angle estimates for the one or more measurement units;
• identifying a mud angle associated with the electromagnetic imager tool from the plurality of mud angle estimates that minimizes based on an amount of variation between the averaged mud effect removed quantities across the one or more measurement units;
• and
• generating, using the identified mud angle, an image of the formation in which the mud effect is removed.

A non-transitory computer-readable storage medium having stored therein instructions which, when executed by a processor of an electromagnetic imaging system, cause the processor to perform operations for reducing mud effect while imaging formations surrounding a wellbore, the operations comprising:

• receiving a plurality of tool measurements made through one or more measurement units of an electromagnetic imager tool operating to log a wellbore in a formation, wherein the one or more measurement units have azimuthal sensitivity, the plurality of tool measurements including contributions from both mud and formation;
• applying one or more mud effect removal techniques to the plurality of tool measurements across a plurality of mud angle estimates to generate a plurality of mud effect removed quantities for the one or more measurement units across the plurality of mud angle estimates;
• averaging the plurality of mud effect removed quantities for the one or more measurement units to generate averaged mud effect removed quantities at each of the plurality of mud angle estimates for the one or more measurement units;
• identifying a mud angle associated with the electromagnetic imager tool from the plurality of mud angle estimates that minimizes an amount of variation between the averaged mud effect removed quantities across the one or more measurement units;
• and
• generating, using the identified mud angle, an image of the formation in which the mud effect is removed.