A method includes deploying a logging tool in a borehole formed in a subsurface formation, the logging tool having a transmitter and a receiver, wherein a condition that is present during logging comprises at least one of a shape of the borehole is non-circular and the logging tool is off-center within the borehole. The method includes emitting, by the transmitter, a signal into subsurface formation and detecting, by the receiver, a response to the signal being propagated through the subsurface formation. The method includes creating, from the response, a borehole image that includes features in the subsurface formation and correcting the features, wherein correcting the features comprises mapping points of a non-circular shape in the borehole image into a plane substantially perpendicular to an axis of the borehole.

A system and for providing a bore sight in a piercing tool. A transmitter emits a magnetic field. The flux lines which emanate along the transmitter axis are substantially straight. A receiver at a remote, target location can detect these flux lines. The receiver and transmitter are oriented such that the substantially straight flux line are along an intended bore path. Then, a piercing tool or other boring tool is oriented along the same path and a bore is created.

Systems and methods are presented for reducing electrical interference in measurement-while-drilling (“MWD”) data. An example may include, among other features a MWD data acquisition system including an analog data reception for receiving analog MWD data, an analog-to-digital conversion circuit, at least one isolation circuit for electrically isolating the analog data reception circuit and the analog-to-digital conversion circuit from a digital data transmission circuit. In some embodiments, a power isolation circuit may electrically isolate an analog section power domain from a digital section power domain. The isolation techniques may improve the quality of the analog signal received.

A drill string communication system is described. An uphole transceiver can couple a signal onto the drill string at a power that is always greater that a selectable power for a downhole signal. Communication from a drill rig to an inground tool can be re-initiated using a maximum uphole transmit power of an uphole transceiver. A procedure can establish a new set of transmission parameters for a drill string signal to establish communication between the drill rig and the inground tool. The system can include a walkover locator that receives an active/inactive status-controlled electromagnetic locating signal. Responsive to a locating signal degradation, a reconfiguration command can modify the locating signal. The uphole transceiver and a downhole transceiver can automatically modify at least one parameter of a downhole signal. An uphole receiver can apply a compensation response to a transferred signal to compensate for a drill string channel transfer function.

A drill string communication system is described. An uphole transceiver can couple a signal onto the drill string at a power that is always greater that a selectable power for a downhole signal. Communication from a drill rig to an inground tool can be re-initiated using a maximum uphole transmit power of an uphole transceiver. A procedure can establish a new set of transmission parameters for a drill string signal to establish communication between the drill rig and the inground tool. The system can include a walkover locator that receives an active/inactive status-controlled electromagnetic locating signal. Responsive to a locating signal degradation, a reconfiguration command can modify the locating signal. The uphole transceiver and a downhole transceiver can automatically modify at least one parameter of a downhole signal. An uphole receiver can apply a compensation response to a transferred signal to compensate for a drill string channel transfer function.

Inversion-based workflows are provided for real-time interpretation of the electromagnetic (EM) look-around and look-ahead measurements. The profile of a look-around zone is determined by interpreting EM measurements of a look-around zone. The profile of the look-around zone characterizes formation dip as well as vertical resistivity or resistivity anisotropy of one or more formation layers of the look-around zone. The profile of a look-ahead zone is determined by interpreting EM measurements of the look-ahead zone. The profile of the look-ahead zone characterizes formation dip as well as horizontal resistivity, vertical resistivity or anisotropy of one or more formation layers of the look-ahead zone. The workflows can also involve interpretation of look-around resistivity measurements to aid in the characterization of the look-around zone.

Inversion-based workflows are provided for real-time interpretation of the electromagnetic (EM) look-around and look-ahead measurements. The profile of a look-around zone is determined by interpreting EM measurements of a look-around zone. The profile of the look-around zone characterizes formation dip as well as vertical resistivity or resistivity anisotropy of one or more formation layers of the look-around zone. The profile of a look-ahead zone is determined by interpreting EM measurements of the look-ahead zone. The profile of the look-ahead zone characterizes formation dip as well as horizontal resistivity, vertical resistivity or anisotropy of one or more formation layers of the look-ahead zone. The workflows can also involve interpretation of look-around resistivity measurements to aid in the characterization of the look-around zone.

A method and system for communicating with a bottom hole assembly from the surface. The method may comprise drilling into a formation with the bottom hole assembly, disposing at least one porous pot on the surface, emitting an electromagnetic field from the transmitter, sensing a voltage of the electromagnetic field with the at least one porous pot, and measuring the voltage with the porous pot. A system may comprise a downhole tool, wherein the downhole tool is disposed on the bottom hole assembly, a drill string, wherein the drill string is attached to the bottom hole assembly and a well head, a drill bit, and at least one porous pot, wherein the at least one porous pot is disposed on the surface and wherein the at least one porous pot is configured to sense and measure a voltage from the electromagnetic field.

A method of communicating through the earth which includes the steps of using a digital pulse train to generate a sweep pulse train which controls the frequency of a magnetic field at a first location, and at a second location, detecting the magnetic field and producing a signal at a frequency dependent on the frequency of the sweep pulse train, and extracting a replica of the digital pulse train from the signal.

A method of communicating through the earth which includes the steps of using a digital pulse train to generate a sweep pulse train which controls the frequency of a magnetic field at a first location, and at a second location, detecting the magnetic field and producing a signal at a frequency dependent on the frequency of the sweep pulse train, and extracting a replica of the digital pulse train from the signal.