Enhanced resistivity measurement apparatus, methods, and systems

A processor-implemented method, to execute on one or more processors that perform the method, comprising:

• acquiring formation signals from a deep measurement electromagnetic antenna array comprising multiple elements including at least one transmitter antenna and one receiver antenna, and an at-bit resistivity (ABR) sensor, values of the formation signals depending on properties of a geological formation, wherein the ABR sensor comprises a drill bit electrically coupled to a toroid or to multiple electrodes, the electrodes separated by at least one gap;
• and
• inverting the values of the formation signals to transform the values into an enhanced resistivity measurement for the geological formation, wherein the inverting comprises determining at least one of relative distance between layers of the geological formation, relative orientation of the layers to a housing, or a resistivity gradient of the layers, wherein the layers are not locally penetrated by the bit.

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:

• acquiring formation signals from a deep measurement electromagnetic antenna array comprising multiple elements including at least one transmitter antenna and one receiver antenna, and an at-bit resistivity (ABR) sensor, values of the formation signals depending on properties of a geological formation, wherein the ABR sensor comprises a drill bit electrically coupled to a toroid or to multiple electrodes, the electrodes separated by at least one gap;
• and
• inverting the values of the formation signals to transform the values into an enhanced resistivity measurement for the geological formation, wherein the inverting comprises determining at least one of relative distance between layers of the geological formation, relative orientation of the layers to a housing, or a resistivity gradient of the layers, wherein the layers are not locally penetrated by the bit.