Abstract: Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety of phase cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and undesired signals are canceled.

Abstract: Technologies applicable to NMR detection of water and hydrocarbons during induced alteration: processes are disclosed. NMR measurements may be used to monitor properties of subsurface fluids within a subsurface formation. NMR measurement devices may be deployed proximal to or within a subsurface formation that contains hydrocarbons. Multiple NMR measurements may be performed during an induced alteration process applied, to the subsurface formation to determine properties of the subsurface formation or fluid as the induced alteration process progresses. Changes in properties of the subsurface formation or fluid may be determined and may be used to determine efficacy of optimize, or otherwise modify the induced alteration process.

Abstract: Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

Abstract: A multicoil NMR detection and imaging apparatus allows multicoil NMR detection and imaging to be performed efficiently at low operating frequencies. The apparatus comprises an AC voltage generator, a transmit switching circuit, a coil switching network, an array of two or more detection coils, a set of receive switching circuits with one switching circuit for each detection coil, and a set of preamplifier circuits with input impedance substantially greater than the impedance of each respective detection coil at the intended operating frequency. The AC generator produces an alternating current waveform that is routed through one of more detection coils during transmit mode while the preamplifier circuits are isolated from the detection coil(s). During receive mode the AC generator is isolated from the detection coils to prevent noise from the transmitter from degrading the quality of received signals.

Abstract: Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety of phase cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and undesired signals are canceled.

Abstract: A multicoil NMR detection and imaging apparatus allows multicoil NMR detection and imaging to be performed efficiently at low operating frequencies. The apparatus comprises an AC voltage generator, a transmit switching circuit, a coil switching network, an array of two or more detection coils, a set of receive switching circuits with one switching circuit for each detection coil, and a set of preamplifier circuits with input impedance substantially greater than the impedance of each respective detection coil at the intended operating frequency. The AC generator produces an alternating current waveform that is routed through one of more detection coils during transmit mode while the preamplifier circuits are isolated from the detection coil(s). During receive mode the AC generator is isolated from the detection coils to prevent noise from the transmitter from degrading the quality of received signals.

Abstract: A multicoil NMR detection and imaging apparatus allows multicoil NMR detection and imaging to be performed efficiently at low operating frequencies. The apparatus comprises an AC voltage generator, a transmit switching circuit, a coil switching network, an array of two or more detection coils, a set of receive switching circuits with one switching circuit for each detection coil, and a set of preamplifier circuits with input impedance substantially greater than the impedance of each respective detection coil at the intended operating frequency. The AC generator produces an alternating current waveform that is routed through one of more detection coils during transmit mode while the preamplifier circuits are isolated from the detection coil(s). During receive mode the AC generator is isolated from the detection coils to prevent noise from the transmitter from degrading the quality of received signals.

Abstract: Technologies applicable to noise canceling in-situ NMR detection and imaging are disclosed. An example noise canceling in-situ NMR detection apparatus may comprise one or more of a static magnetic field generator, an alternating magnetic field generator, an in-situ NMR detection device, an auxiliary noise detection device, and a computer.

Abstract: A multicoil NMR detection and imaging apparatus allows multicoil NMR detection and imaging to be performed efficiently at low operating frequencies. The apparatus comprises an AC voltage generator, a transmit switching circuit, a coil switching network, an array of two or more detection coils, a set of receive switching circuits with one switching circuit for each detection coil, and a set of preamplifier circuits with input impedance substantially greater than the impedance of each respective detection coil at the intended operating frequency. The AC generator produces an alternating current waveform that is routed through one of more detection coils during transmit mode while the preamplifier circuits are isolated from the detection coil(s). During receive mode the AC generator is isolated from the detection coils to prevent noise from the transmitter from degrading the quality of received signals.

Abstract: Methods and systems for a universally applicable, linear, signal processing framework for optimal detection, localization, and feature extraction of dipolar magnetic and electromagnetic (EM) targets. Such methods and systems provide the ability to, for example, simultaneously and optimally solve the problems of detection, localization and estimation of the dipole vector or target response matrix; be applicable to different types of magnetic or EMI sensor system; and be applicable to arbitrary combinations of sensor locations and orientations, and arbitrary spatial sampling. Such functionality is provided, in various aspects of the disclosure, with a quadrature matched filter algorithm for detecting and imaging magnetic dipoles to the more complex realm of single- and multi-channel EMI sensors.

Abstract: A multicoil NMR data acquisition apparatus and processing method for performing three-dimensional magnetic resonance imaging in a static magnetic field without the application of controlled static magnetic field gradients. A preferred application relates specifically to the detection and localization of groundwater using the Earth's magnetic field. Multicoil arrays are used in both transmit and receive modes, and coherent data processing algorithms applied to the data to generate three-dimensional NMR spin density estimates. Disclosed are methods for acquiring NMR data using an array of at least two transmit and receive coils, and for processing such multicoil data to estimate the three-dimensional NMR spin density distributions.

Abstract: A method to model the NMR signal and/or noise functions as stochastic processes. Locally relevant statistics for the signal and/or noise processes are derived directly from the set of individual coil images, in the form of array correlation matrices, by averaging individual coil image cross-products over two or more pixel locations. An optimal complex weight vector is computed on the basis of the estimated signal and noise correlation statistics. The weight vector is applied to coherently combine the individual coil images at a single pixel location, at multiple pixel locations, or over the entire image field of view (FOV).

Abstract: A multicoil NMR data acquisition apparatus and processing method for performing three-dimensional magnetic resonance imaging in a static magnetic field without the application of controlled static magnetic field gradients. A preferred application relates specifically to the detection and localization of groundwater using the Earth's magnetic field. Multicoil arrays are used in both transmit and receive modes. and coherent data processing algorithms applied to the data to generate three-dimensional NMR spin density estimates. Disclosed are methods for acquiring NMR data using an array of at least two transmit and receive coils, and for processing such multicoil data to estimate the three-dimensional NMR spin density distributions.