A method that includes deploying a casing with a multi-electrode configuration over a dielectric layer in a downhole environment. The method also includes collecting electromagnetic (EM) measurements using the multi-electrode configuration, and processing the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall. A related system includes a casing deployed downhole, the casing having a multi-electrode configuration and a dielectric layer between the casing and the multi-electrode configuration. The system also includes a controller for directing collection of EM measurements using the multi-electrode configuration, and a processor that processes the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall.

An apparatus for measuring resistivity in a borehole includes first and second modules configured to be conveyed through the borehole and a transmitter connected to the first module, the transmitter transmitting a transmitter signal that causes a field signal to be created in a formation surrounding the borehole. The apparatus also includes a receiver connected to the second module configured to sense the field signal, a reflection generator and a delay determination circuit that includes a pulse generator and a timer. The apparatus also includes a communication link coupling the delay determination circuit and the reflection generator. The delay determination circuit causes a first pulse to be transmitted to the reflection generator and determines an indication that is related to the time until a reflection is received back from the reflection generator.

Various embodiments include apparatus and methods to operate an induction measurement process in a borehole that addresses direct coupling of a signal between sensors of a measuring tool. Apparatus and methods can include a processing unit to generate formation parameters from signals received in the measurement tool. Additional apparatus, systems, and methods are disclosed.

Various embodiments include apparatus and methods to operate an induction measurement process in a borehole that addresses direct coupling of a signal between sensors of a measuring tool. Apparatus and methods can include a processing unit to generate formation parameters from signals received in the measurement tool. Additional apparatus, systems, and methods are disclosed.

Transient responses of a tri-axial resistivity tool corresponding to an electromagnetic (EM) impulse are derived. A transient response of a directional resistivity tool (DRT) corresponding to the EM impulse is derived based on the transient responses of the tri-axial resistivity tool. A theoretical late time transient response of the DRT is derived based on the transient response of the DRT. The late time transient response of the DRT is measured. An anisotropy, a horizontal conductivity, and a dip angle are determined based on the measured late time transient response and the theoretical late time transient response.

Transient responses of a tri-axial resistivity tool corresponding to an electromagnetic (EM) impulse are derived. A transient response of a directional resistivity tool (DRT) corresponding to the EM impulse is derived based on the transient responses of the tri-axial resistivity tool. A theoretical late time transient response of the DRT is derived based on the transient response of the DRT. The late time transient response of the DRT is measured. An anisotropy, a horizontal conductivity, and a dip angle are determined based on the measured late time transient response and the theoretical late time transient response.

Systems, tools, and methods are disclosed that utilize at least one integrated computational element to measure a property of a substance in close proximity to the substance's source. More specifically, systems, tools, and methods are presented that allow the interaction of electromagnetic radiation and the optically-processing of interacted electromagnetic radiation in proximity to an emergence of a fluid from the fluid's source. The integrated computational elements optically-process the interacted electromagnetic radiation into a weighted optical spectrum. The weighted optical spectrum enables the determination of various chemical or physical characteristics of the fluid.

Systems, tools, and methods are disclosed that utilize at least one integrated computational element to measure a property of a substance in close proximity to the substance's source. More specifically, systems, tools, and methods are presented that allow the interaction of electromagnetic radiation and the optically-processing of interacted electromagnetic radiation in proximity to an emergence of a fluid from the fluid's source. The integrated computational elements optically-process the interacted electromagnetic radiation into a weighted optical spectrum. The weighted optical spectrum enables the determination of various chemical or physical characteristics of the fluid.

Systems and methods for acquiring and processing electromagnetic data in subsurface formations. In one example, a system includes an electromagnetic source, a plurality of electromagnetic receivers, and an electromagnetic data processor. The electromagnetic source is configured to generate an electromagnetic pulse that induces electromagnetic energy in subsurface formations. The electromagnetic receivers are configured to detect the electromagnetic energy reflected by the subsurface formations, and to output signals corresponding to detected electromagnetic energy reflected by the subsurface formations. The electromagnetic data processor configured to process, based on differences in travel times of the electromagnetic energy between the subsurface formations and the electromagnetic receivers, the signals output by the electromagnetic receivers. The electromagnetic data processor is further configured to produce a representation of the subsurface formations based on processed signals output by the electromagnetic receivers.

Systems and methods for acquiring and processing electromagnetic data in subsurface formations. In one example, a system includes an electromagnetic source, a plurality of electromagnetic receivers, and an electromagnetic data processor. The electromagnetic source is configured to generate an electromagnetic pulse that induces electromagnetic energy in subsurface formations. The electromagnetic receivers are configured to detect the electromagnetic energy reflected by the subsurface formations, and to output signals corresponding to detected electromagnetic energy reflected by the subsurface formations. The electromagnetic data processor configured to process, based on differences in travel times of the electromagnetic energy between the subsurface formations and the electromagnetic receivers, the signals output by the electromagnetic receivers. The electromagnetic data processor is further configured to produce a representation of the subsurface formations based on processed signals output by the electromagnetic receivers.