Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith.

A system and method for monitoring a wellbore are disclosed herein. A pulse generator comprises a plurality of ports, wherein a first one of the plurality of ports is coupled to a first location of interest and a second one of the plurality of ports is coupled to a second location of interest. An electromagnetic pulse is generated at the first port and the second port. A reflected electromagnetic pulse is received at the first port and the second port. In another embodiment, the pulses are received at a separate pulse receiver with a plurality of receiving ports. A data storage device is coupled to the pulse generator or the pulse receiver, and data relating to the reflected magnetic pulse is stored at the data storage device.

Naturally-occurring, electromagnetic signals generated by interaction of solar wind with earth's magnetosphere adjacent a borehole are measured by an electromagnetic sensor positioned adjacent the borehole in the hydrocarbon-bearing formation. Electromagnetic signals generated within the borehole are measured over a period of time by a borehole sensor positioned within the borehole. The electromagnetic signals change over the period of time due to variations in fluid distributions within the hydrocarbon-bearing formation. Electromagnetic changes to the electromagnetic signals generated within the borehole and to the passive, naturally-occurring electromagnetic signals over the period of time are determined by one or more processors. A computational model of the hydrocarbon-bearing formation is generated based in part on the electromagnetic changes.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

Drilling systems and related methods are disclosed. A drilling systems may include a tool configured to be positioned at an end of a drill string adjacent a drill bit, and the tool may be configured to detect localized seismo-electromagnetic conversion from one or more predetermined positions within a medium ahead of the drill bit. The tool may include two or more pressure sources configured to generate focused acoustic and/or elastic energy at the one or more predetermined positions to generate the localized seismo-electric conversion.

A sensor system to prevent the unintended severing or damage to a cable or other object within the throughbore of a standpipe or wellhead that may include a blowout preventer and gate valves. Generally, a sensor which may include both an emitter and receiver, is affixed externally to the standpipe, wellhead, blowout preventer, or gate valves. None of the emitter or receiver penetrates the pressure vessel formed by the standpipe, wellhead, blowout preventer, or gate valves. The sensor system may detect disturbances in a pre-existing field such as a geomagnetic sensor detecting the earth's magnetic field, the sensor may create a field and then detect disturbances within that created field such as a magnetic sensor, or the sensor may send a pulse of energy towards the area to be sensed and then read the reflected energy. Generally, the sensor system includes a logic controller, a memory, a sensor or sensors that may or may not include emitters and receivers, and a display. I

An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a calibration EM transmitter for generating a calibration signal; a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the calibration signal; and a calibration device connected to the calibration EM transmitter and to the receiver, the calibration device configured to control a frequency and waveform of the calibration signal. The calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.