Abstract: A pressure wave system having a tubular member, a signal source, a sensor, and a source of noise, has a noise interference system employing one or more a lateral branches to cancel pressure noise, and/or amplify or filter the pressure wave signal. A related method generates the pressure wave signal, connects the lateral branch or branches to amplify or filter the signal and/or cancel noise from the system, and receives the signal or a response of the system to the signal. The lateral branches are simple pipe stubs or loops that can be made using ordinary piping components, or are more complex designs.

Abstract: A reamer for enlarging an underground borehole comprises a plurality of cutter assemblies distributed azimuthally around a longitudinal axis of the tool, and each cutter assembly comprises a supporting structure and a plurality of hard faced cutters (211-216) embedded therein with a hard face of each cutter exposed and facing in a direction of rotation of the tool. Each cutter assembly includes at least one outward-facing gauge surface (220), at a radial distance from the tool axis which aligns the gauge surface with the radially outer extremity (218) of at least one cutter. This gauge surface (220) extends (221) in the direction of rotation circumferentially ahead of the extremity of the exposed face of the aligned at least one cutter. It may meet the side of the assembly at a curved (222) or bevelled (342) edge and may also extend back from the exposed face of the cutter.

Abstract: This disclosure describes systems and methods to predict viscosity of heavy oil in a geological formation, even when the geological formation also contains water such as clay-bound water, using a downhole nuclear magnetic resonance (NMR) tool. The downhole NMR tools may obtain responses include distributions of a first relaxation time T1, a second relaxation time T2, or diffusion, or a combination of these. The responses of the NMR measurements that are due to water are separated from the responses of the NMR measurements that are due to heavy oil. The responses of the NMR measurements due to heavy oil are then related to likely values of viscosity of the heavy oil based on empirical or simulated measurements.

Abstract: Acoustic imaging waveforms are measured utilizing a downhole acoustic tool within a wellbore, and then aligned relative to a main echo of each waveform. The aligned waveforms are then subjected to a first low-pass filter. Residuals are extracted by determining differences between the aligned waveforms and the filtered waveforms. The residuals are aligned to corresponding acoustic firing pulses of the downhole acoustic tool. The aligned residuals are subjected to a second low-pass filter. The measured waveforms are aligned to the corresponding acoustic firing pulses. Noise associated with the downhole acoustic tool is removed from the pulse-aligned, measured waveforms utilizing the filtered residuals.

Abstract: Method and apparatus for assessing health of fracturing fluid pump assemblies and other wellsite equipment. For example, predicted data indicative of a first operational parameter of a pump assembly is generated utilizing: a model relating the first operational parameter to each of a plurality of second operational parameters of the pump assembly; and real-time data indicative of each of the second operational parameters. Health of the pump assembly is then assessed based on: the predicted data indicative of the first operational parameter; and real-time data indicative of the first operational parameter.

Abstract: A method includes admixing an aqueous polysaccharide solution into an oleaginous base fluid, and adding a divalent ion source to produce one or more polysaccharide microspheres.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both, contains first fluid that includes a native reservoir fluid of the geological formation and a contaminant. The method also includes receiving a portion of the first fluid into the downhole acquisition tool and determining a plurality of properties of the portion of the first fluid using the downhole acquisition tool. The plurality of properties includes a mass fraction of a component of the portion of the first fluid and a density of the portion of the first fluid. The method also includes using the processor to estimate a volume fraction of the contaminant in the portion of the first fluid based at least in part on a composition mass fraction function that depends at least on the mass fraction of the component in the portion of the first fluid and the density of the portion of the first fluid.

Abstract: A method for making dynamic gravity toolface measurements while rotating a downhole measurement tool in a borehole is disclosed. The method includes processing magnetic field measurements and accelerometer measurements to compute a toolface offset and further processing the toolface offset in combination with a magnetic toolface to obtain the dynamic gravity toolface. Methods for correcting dynamic and static navigational sensor measurements to remove sensor biases, for example, are also disclosed.

Abstract: A method for processing microseismic data, comprises: receiving the microseismic data acquired by one or more multicomponent sensors; convolving the microseismic data with an operator that is applied to all of the components of the microseismic data; and applying a multicomponent filter operator to the convolved microseismic data. The microseismic data may result from human activity or be entirely natural. The filtering preserves the polarity of the received data while improving the signal-to-noise ratio of the filtered data.

Abstract: A technique facilitates servicing of a subterranean formation by treating a specific section of a well. The technique utilizes a straddle packer conveyed downhole and then activated via coiled tubing. The straddle packer comprises a first, e.g. upper, packer and a second, e.g. lower, packer which are deployed downhole into the wellbore to the specific section of the wellbore proximate a target formation zone. Once properly located, the straddle packer is uniquely activated by compression and tension inputs applied via the coiled tubing.

Abstract: A downhole tool having a transmitter array with azimuthally spaced transmitters and receiver arrays with azimuthally spaced receivers. Methods of operation include transmitting an acoustic signal from an individual one of the transmitters, sensing an attribute of the acoustic signal with the receivers, and evaluating a characteristic of a portion of a downhole feature based on response signals generated by the first and second receivers. Each response signal is indicative of the acoustic signal attribute sensed by the corresponding receivers. This is repeated with different individual ones of the transmitters and receivers until the evaluated portions of the downhole feature collectively extend around a wellbore.

Abstract: A method including positioning a downhole acquisition tool in a wellbore in a geological formation; performing a pretest sequence to gather at least one of pressure or mobility information based on downhole acquisition from a sample line, a guard line, or both while the downhole acquisition tool is within the wellbore. The pretest sequence includes controlling a valve assembly to a first valve configuration that may allow the fluid to flow into the downhole tool via one or more flowlines toward a pretest system. The one or more flowlines include the sample line only, the guard line only, or both the sample line and the guard line; and drawing in the fluid through the one or more flowlines. The method also includes controlling the valve assembly to a second valve configuration. The second valve configuration is different from the first valve configuration and may block the one or more flowlines from drawing in the fluid.

Abstract: Apparatus and methods for utilizing pressure exchangers as a source of pressure oscillations. An example method includes operating a plurality of pressure exchangers to pressurize a stream of fluid, injecting the pressurized stream of fluid into a wellbore extending into a sub-terranean formation, and controlling rotational speed and rotational position of a rotor of each of the pressure exchangers to control amplitude and/or frequency of pressure oscillations within the pressurized stream of fluid being injected into the wellbore.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both contains a fluid that includes a native reservoir fluid of the geological formation and a contaminant. The method also includes receiving a portion of the fluid into the downhole acquisition tool, measuring a fluid property of the portion of the fluid using the downhole acquisition tool, and using the processor to estimate a fluid property of the native reservoir fluid based on the measured fluid property of the portion of the fluid and a regression model that may predict an asymptote of a growth curve. The asymptote corresponds to the estimated fluid property of the native formation fluid, and the regression model includes a geometric fitting model other than a power-law model.

Abstract: Methods are disclosed for detecting fluid in at least one annulus around at least one casing installed in a borehole traversing a formation utilizing a sonic tool. The sonic tool is activated in the borehole and the received sonic waveforms are processed to obtain a dispersion plot. A reference dispersion plot is generated using a model of the borehole where the casing is well-bonded by cement. The obtained and reference dispersion plots are compared. An indication of fluid and in some cases, the specific radial location thereof is obtained based on the signature of the obtained plot as opposed to the reference plot. The methods are effective in doubly-cased boreholes using monopole and/or dipole sources.

Abstract: A method, apparatus, and program product estimate anisotropic properties of an anisotropic formation based at least in part on determinations of a deviation of a wellbore associated with the anisotropic formation and an availability of non-sonic measurement data associated with the anisotropic formation. The determinations are used in the selection of at least one computer-implemented model that in turn may be applied to determine one or more unknown elastic constants for an elastic stiffness matrix.

Abstract: An apparatus that includes a housing, a flowline extending within the housing, and a member retained within the housing and substantially comprising thermally conductive material. The flowline is retained in a substantially cylindrical surface of the member. A heat-generating electrical component is mounted to the member.

Abstract: A distributed temperature sensing (DTS) system is connected to a buried fiber optic cable that is used to monitor a structure. The DTS system is operated to obtain temperature measurements along the length of the fiber cable. The temperature measurements are then used to calculate a measure of diurnal temperature variability at each point along the cable. This calculation is used to identify points at which the diurnal temperature variability changes rapidly over a short length of the cable. These points can be identified with features along the cable, such as splice chambers, where the cable burial conditions change. The known geographic location of these features can then be identified with specific distances along the fiber.

Abstract: Certain embodiments disclosed herein are directed to devices for cooling. In certain examples, a thermoelectric device comprising a substrate and a superlattice coupled to the substrate is disclosed. In some examples, the superlattice includes a first semi-conducting material and a second semi-conducting material coupled to the first semi-conducting material to provide an interface between the first and second semi-conducting materials.

Abstract: A test method and apparatus employs a microfluidic device to characterize properties of a fluid. The microfluidic device has an inlet port, an outlet port, and a microchannel as part of a fluid path between the inlet port and the outlet port. While a fluid is introduced into the microchannel, the fluid temperature is maintained while the fluid pressure in the microchannel is varied to characterize the properties of the fluid in the microchannel. The properties of the fluid can relate to a scale onset condition of the fluid at the pressure of the flow through the microchannel. In one aspect, fluid pressure in the microchannel is maintained while the fluid temperature is varied to characterize the properties of the fluid. In another aspect, flow rate of the fluid through the microchannel is varied while the fluid temperature is maintained to characterize the properties of the fluid in the microchannel.