A method for mapping underground sensors onto a network map may include obtaining a plurality of magnetic measurements from a plurality of sensors. The method may include using the plurality of magnetic measurements for determining a plurality of sensor locations in an initial network map. The method may include generating updated network maps from the perspective of each localized sensor. The method may include merging the updated network maps into a final network map, the final network map comprising a most accurate location for each sensor. The method may include determining inner localized sensors out of the plurality of sensors in the final network map. The method may include identifying the inner localized sensors as new base station anchors. The method may include mapping the inner localized sensors onto the final network map as new base station anchors.

A method for mapping underground sensors onto a network map may include obtaining a plurality of magnetic measurements from a plurality of sensors. The method may include using the plurality of magnetic measurements for determining a plurality of sensor locations in an initial network map. The method may include generating updated network maps from the perspective of each localized sensor. The method may include merging the updated network maps into a final network map, the final network map comprising a most accurate location for each sensor. The method may include determining inner localized sensors out of the plurality of sensors in the final network map. The method may include identifying the inner localized sensors as new base station anchors. The method may include mapping the inner localized sensors onto the final network map as new base station anchors.

An imaging device included in an assembly located in a wellbore during drilling operations may include a cylindrical housing that extends along a central axis thereof. The imaging device may include at least one gradient coil configured to produce a unique magnetic field weaker than a main magnetic field. The at least one gradient coil may create a variable field that is increased or decreased by changing a direction of the unique magnetic field with respect to a direction of the main magnetic field to allow a specific part of a rock formation to be scanned by altering and adjusting the main magnetic field. The imaging device may include at least one radio frequency coil configured to transmit radio frequency waves into the rock formation. The imaging device may include at least one magnet disposed in the cylindrical housing that resonates against the unique magnetic field.

An imaging device included in an assembly located in a wellbore during drilling operations may include a cylindrical housing that extends along a central axis thereof. The imaging device may include at least one gradient coil configured to produce a unique magnetic field weaker than a main magnetic field. The at least one gradient coil may create a variable field that is increased or decreased by changing a direction of the unique magnetic field with respect to a direction of the main magnetic field to allow a specific part of a rock formation to be scanned by altering and adjusting the main magnetic field. The imaging device may include at least one radio frequency coil configured to transmit radio frequency waves into the rock formation. The imaging device may include at least one magnet disposed in the cylindrical housing that resonates against the unique magnetic field.

Disclosed herein are methods and systems for monitoring fluid flow in a rock formation that include utilizing a tracer fluid containing a homogeneous dispersion of ultrastable magnetic nanoparticles which can be injected into the rock formation. A series of EM signals can be emitted in formation by a transmitter at a first plurality of discrete depths along a first path, that can be recorded by a receiver at a second plurality of locations at a second plurality of discrete depth. The received EM signals can be processed to generate a set of EM permeability data that is indicative of variations in magnetic permeability between the first path and the second path. A magnetic permeability map can be generated that is indicative of a location of the tracer fluid.

Disclosed herein are methods and systems for monitoring fluid flow in a rock formation that include utilizing a tracer fluid containing a homogeneous dispersion of ultrastable magnetic nanoparticles which can be injected into the rock formation. A series of EM signals can be emitted in formation by a transmitter at a first plurality of discrete depths along a first path, that can be recorded by a receiver at a second plurality of locations at a second plurality of discrete depth. The received EM signals can be processed to generate a set of EM permeability data that is indicative of variations in magnetic permeability between the first path and the second path. A magnetic permeability map can be generated that is indicative of a location of the tracer fluid.

A downhole sensor deployment assembly includes a body attachable to a completion string and one or more arms pivotably coupled to the body. A sensor pad is coupled to each arm and movable from a retracted position, where the sensor pad is stowed adjacent the completion string, and an actuated position, where the sensor pad is extended radially away from the completion string. One or more actuators are pivotably coupled to the body at a first end and pivotably coupled to a corresponding one of the one or more arms at a second end, the one or more actuators being operable to move the sensor pad to the actuated position. One or more sensor devices are coupled to the sensor pad for determining a resistivity of a formation, the one or more sensor devices comprising at least one of a sensing electrode, a transceiver, and a transmitter.

A downhole sensor deployment assembly includes a body attachable to a completion string and one or more arms pivotably coupled to the body. A sensor pad is coupled to each arm and movable from a retracted position, where the sensor pad is stowed adjacent the completion string, and an actuated position, where the sensor pad is extended radially away from the completion string. One or more actuators are pivotably coupled to the body at a first end and pivotably coupled to a corresponding one of the one or more arms at a second end, the one or more actuators being operable to move the sensor pad to the actuated position. One or more sensor devices are coupled to the sensor pad for determining a resistivity of a formation, the one or more sensor devices comprising at least one of a sensing electrode, a transceiver, and a transmitter.

A well casing is cemented in a well bore in a subterranean formation by pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus surrounding the well casing. While pumping the cement slurry, the position of the top of the cement slurry in the annulus is sensed, and the rise of the sensed position of the top of the cement slurry in the annulus is recorded as a function of time. The recording is analyzed to evaluate the cement job. For example, the analysis may indicate a problem addressed by adjusting a cement plan for a future cement job, and the analysis may indicate a need to repair a location of the set cement by perforating the well casing at the location to be repaired, and pumping cement slurry down the well casing to fill the location to be repaired.

Methods, systems and devices for evaluating an earth formation, including an electromagnetic (EM) well logging apparatus for investigating a formation from a fluid-filled borehole intersecting the formation. Apparatus include a carrier body having a pocket formed in an outer surface, the pocket being defined by a plurality of walls and a bottom; a pad configured to emit EM energy, the pad having an outer face, a plurality of sides complementary to the plurality of walls, and an inner face positioned adjacent to the bottom, wherein the pad is movably disposed in the pocket such that a gap separates at least one wall of the plurality of walls and at least one side of the plurality of sides; and at least one electrically conductive member forming an electrical connection between the carrier body and the pad and covering the gap. The pad may be slideably disposed in the pocket.