Vista Clara Inc.

Elliot D Grunewald

David Oliver Walsh

Hong Zhang

Nuclear Magnetic Resonance (NMR) electronics that employ selective solid-state isolation of circuit elements can include solid-state switches, such as back-to-back Field Effect Transistor (FET) pairs, and isolated gate drive electronics adapted to operate the solid-state switches in order to selectively decouple induction coils from receive electronics. The solid-state switches can be placed in series to achieve higher standoff voltages, and can be configured for low on resistance and short switching times. The gate drive electronics can include electrical isolation components adapted to enhance standoff voltages and reduce electrical noise at the selectively isolated receive electronics.

Selective solid-state isolation of NMR circuit elements using back-to-back field effect transistors

Technologies including NMR relaxation time estimation methods and corresponding apparatus are disclosed. Example techniques may include performing at least one single-pulse acquisition sequence, the single-pulse acquisition sequence comprising transmitting a single modulated pulse with a surface coil, wherein the phase, frequency, or amplitude of the single modulated pulse is varied during the single modulated pulse, and wherein the single modulated pulse excites a transverse magnetization component within a subsurface fluid. The resulting NMR signal may be recorded on at least one receiving device, including recording the NMR signal associated with the transverse magnetization component excited by the single modulated pulse. Processing techniques may be applied in which recorded NMR response data are used to estimate NMR properties and the relaxation times Tand T* as a function of position as well as one-dimensional and two-dimension distributions of Tversus T* as a function of subsurface position.

Relaxation time estimation in surface NMR

Technologies applicable to SNMR pulse sequencing are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting SNMR pulse sequences according to any of a variety of techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences.

SNMR pulse sequencing methods and apparatus

NMR relaxation time estimation methods and corresponding apparatus generate two or more alternating current transmit pulses with arbitrary amplitudes, time delays, and relative phases; apply a surface NMR acquisition scheme in which initial preparatory pulses, the properties of which may be fixed across a set of multiple acquisition sequence, are transmitted at the start of each acquisition sequence and are followed by one or more depth sensitive pulses, the pulse moments of which are varied across the set of multiple acquisition sequences; and apply processing techniques in which recorded NMR response data are used to estimate NMR properties and the relaxation times Tand T* as a function of position as well as one-dimensional and two-dimension distributions of Tversus T* as a function of subsurface position.

Technologies applicable to detection and characterization of subsurface contaminants by NMR and dielectric measurements are disclosed. The disclosed technologies include methods for obtaining and combining data from NMR and dielectric measurements to detect, quantify, and characterize non-native non-aqueous phase liquid (NAPL) contaminants located in geologic materials.

Combination NMR and dielectric measurement

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.

NMR detection of water and hydrocarbons during induced alteration processes

Technologies applicable to surface-based NMR measurement are disclosed. A surface probe is positionable at or above a surface of the Earth and adapted to make NMR measurements of shallow or very shallow subsurface volumes. NMR spectrometer components connected to the surface probe are configured to control electromagnetic pulses produced by the surface probe and to record resulting detected NMR signals from the subsurface volume.

Surface-based NMR measurement

Nuclear Magnetic Resonance (NMR) measurement apparatus, NMR sensors, NMR measurement methods are disclosed to determine NMR properties of engineered flow management structures, and to estimate engineering properties using determined NMR properties. Example engineered flow management structures include engineered water storage, water management, water production, water sampling structures, and/or structures that serve as conduits or barriers to water movement. Technologies disclosed herein are also applicable to measuring properties relating to other fluid and/or gas flow in engineered flow management structures.

NMR measurement of engineered flow management structures

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.

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Seattle, WA, United States of America

Elliot D Grunewald