Abstract: A method and apparatus for detecting the presence of mineral seams during coal or ore mining operations. A mining machine with a cutter drum includes a detector assembly that includes two detectors attached near the surface cut by the cutter drum. The detectors include downward facing windows that receive gamma radiation from mined material and undesirable material. One detector is positioned lower than the other and over a trench created below the surface cut by the cutter drum. The cutting depth of the cutter drum may be controlled based on radiation levels detected by the detectors.

Abstract: A method for downhole fluid analysis is disclosed. The method includes positioning a downhole fluid sampling tool at first and second locations; extracting and compositionally analyzing samples of reservoir fluid while positioned at the first and second locations; comparing analysis results; and repositioning the tool to a third location depending on the results of the comparison. The compositional analysis can be performed using downhole gas chromatography and mass spectrometry systems and preferably can identify subtle non-homogeneities such as biomarkers. The fluid extraction can be performed using a focuses dual-flowline type sampling probe.

Abstract: A portable system for elemental analysis includes one or more neutron emitters, a chamber for containing a test sample, at least one gamma ray detector electrically connected to a data acquisition system, and software or firmware executing on the data acquisition system from a non-transitory physical medium, the software or firmware providing a first function for producing one or more gamma ray spectrums, a second function for applying correction factors to the one or more gamma ray spectrums, and a third function for analyzing the corrected gamma ray spectrum or spectrums to determine a deconvolved elemental composition of the test sample.

Abstract: Pulse sequences are applied to a fluid in an earth formation in a static magnetic field and NMR spin echo signals are obtained. The signals are processed to give a distribution of relaxation time at each of the plurality of depths. A quasi-DNA is obtained by autoscaling and a nonlinear mapping of T2 component logs and non-NMR logs. Similarities between the quasi-DNA of the two types of logs are used to estimate formation lithology and fluids.

Abstract: Systems, methods, and devices are provided to determine an accurate neutron-gamma density (NGD) measurement for a broad range of formations, including low-hydrogen-index or low-porosity formations and formations with heavy elements. For example, such an NGD measurement may be obtained by emitting neutrons into a formation such that some of the neutrons inelastically scatter off elements of the formation and generate inelastic gamma rays. The neutrons and inelastic gamma rays that return to the downhole tool may be detected. Some characteristics of certain formations are believed to affect the fast neutron transport of the formations. Thus, if a formation has one or more of such characteristics, a correction may be applied to the count rate of neutrons, the count rate of inelastic gamma rays, or the neutron transport correction function, upon which the neutron-gamma density (NGD) may be determined.

Abstract: A method of estimating at least one property of an earth formation includes: constructing a matrix model of a formation; constructing a shale model of the formation, the shale model including an estimation of a concentration of at least one trace element; combining the first model and the second model to generate a formation model; and comparing measured pulsed neutron data with the mixed model to estimate the at least one property.

Abstract: Well log data is assigned depositional labels by a soft computing method. A model is trained on an expert-interpreted well log by segmenting, assigning fuzzy symbols to the segments, and calculating attribute values for units labeled by the expert. From these values, classifiers are trained for each of a number of depositional types. Finally, a model is developed for translating fuzzy symbols into depositional labels. Once trained, the model is applied to well log data.

Abstract: Systems, methods, and devices for matching the lithology effect of a downhole tool having a lower-energy neutron source, such as AmBe, using a downhole tool having a higher-energy neutron source, such as an electronic neutron generator, are provided. One such downhole tool may include a neutron source, first and second neutron detectors, and data processing circuitry. The neutron source may emit neutrons into a subterranean formation, which may scatter off the formation. The first neutron detector may detect neutrons of a relatively lower spectrum of energies than the second neutron detector. From counts of these neutrons, the data processing circuitry may determine a property of the subterranean formation having a lithology effect that substantially matches another lithology effect associated with another downhole tool having a lower-energy neutron source.

Abstract: Systems, methods, and devices for determining the porosity of a subterranean formation with reduced lithology error are provided. In one example, a downhole tool for such purposes may include a neutron source, a plurality of neutron detectors, and data processing circuitry. The neutron source may be configured to emit neutrons into a subterranean formation, and the plurality of neutron detectors may be configured to detect neutrons scattered from the subterranean formation. At least two of the plurality of neutron detectors may be disposed at different respective distances from the neutron source. The data processing circuitry may be configured to determine a porosity of the subterranean formation based at least in part on a weighted combination of the detector responses from each of the at least two of the plurality of neutron detectors.

Abstract: Methods and systems for simulating an electronic system in a high level modeling system (HLMS). A design block and certain signals of the electronic system are selected. The selected signals include internal signals of the design block that are not ports of the design block. The electronic system is simulated in the HLMS, which includes a hardware-based co-simulation platform and a software-based co-simulation platform. A hardware realization of the design block is automatically generated and the design block is emulated in the hardware based co-simulation platform using the hardware realization of the design block. A sequence of values is displayed for the selected signals of the electronic system. During the simulation of the electronic system in the HLMS, the sequence of values for the internal signals of the design block and another sequence of values for the ports of the design block are transferred between the co-simulation platforms.

Abstract: Hourly CO2 concentration, amount of solar radiation, and plant distribution information are calculated through observation from predetermined satellites. A concentration of CO2 absorbed by plant-chlorophyll per each time unit is calculated. By adding up the CO2 concentration on the earth and the concentration of CO2 absorbed by the plant-chlorophyll, a CO2 concentration obtained provided that no plant-chlorophyll exist is calculated for a certain period. Thereafter, a mean concentration of CO2 that is absorbed according to changes in the distribution of plant-chlorophyll is calculated on the basis of a monthly mean solar radiation amount and plant-chlorophyll distribution information. By subtracting the CO2 concentration, which is a mean, from the total CO2 concentration, a CO2 concentration, which is a normal, is calculated.

Abstract: A method for a pulsed gamma-gamma density tool to simultaneously compensate for interactions due to the photoelectric effect and density variations caused by standoff enables a more precise determination of bulk formation density. This method includes the steps of providing a source of energetic particles and directing those energetic particles at a formation having a known photoelectric factor and electron density and capturing one or more photons either emitted or deflected from the formation either a first detector or a second detector. The first detector is spaced a first distance from the source, the second detector is spaced a second distance from the detector and a third distance separates the first detector from the second detector.

Abstract: A long-range lightning detection and characterization system and method. Electromagnetic radiation produced by a lightning strike is sensed at a sensing location and a measured signal representative of the strike is produced that defines an amplitude versus time. A set of reference data containing waveforms comparable to the measured signal is established. The set of reference data defines a set of reference amplitudes versus time, representative of one or more predetermined reference lightning strikes at various predetermined distances, where for each of the distances, the reference lightning strikes have associated therewith various predetermined day/night percentages. The measured signal is compared with the reference data, the comparison including finding a correlation between the measured signal and a correlating waveform in the reference data.

Abstract: The invention is related to the development of gas condensate deposits and may be used to determine current condensate saturation in the near-wellbore zone in the formation. The method for the current condensate saturation determination in the near-wellbore zone requires the measurement of the formation rock parameters and formation fluid parameters before the start of gas-condensate production and creation of the numerical model of the neutron logging signal change during the production period for the measured formation rock parameters and formation fluid parameters and expected condensate saturation value. During the production period when the well productivity decreases, neutron logging is performed and then the measured signals are matched with the model calculations and based on the provision of the best match of the measured and simulated neutron logging signals condensate saturation is determined.

Abstract: The invention is related to the development of volatile oil deposits and may be used to determine current gas saturation in a near-wellbore zone in a volatile oil formation. The method for the current gas saturation determination in the near-wellbore zone requires the measurement of the formation rock parameters and formation fluid parameters before the gas accumulation start in the near-wellbore zone and creation of the numerical model of the neutron logging signal change during the production period for the measured formation and formation fluid parameters and expected gas saturation value. During the production period when the well productivity decreases, neutron logging is performed and then the measured signals are matched with the model calculations and based on the provision of the best match of the measured and simulated neutron logging signals gas saturation is determined.

Abstract: A method and related system of determining formation density by compensating actual inelastic gamma rays detected from a pulsed-neutron tool for the effects of neutron transport. The method and systems may model response of the tool and use the modeled response as an indication of an amount to compensate detected inelastic gamma rays.

Abstract: Systems, methods, and devices for determining a porosity of a subterranean formation corrected for borehole effects are provided. One such device may be a downhole tool capable of being lowered into a borehole of a subterranean formation that may include a neutron source, two or more neutron detectors, and data processing circuitry. The neutron source may emit neutrons into the subterranean formation. The two or more neutron detectors may be respectively disposed at two or more azimuthal orientations within the downhole tool, and may detect neutrons scattered by the subterranean formation or borehole fluid in the borehole, or both. Based on the neutrons detected by the neutron detectors, the data processing circuitry may determine a porosity of the subterranean formation corrected for borehole effects.

Abstract: A method for estimating resistivity of a formation includes: selecting spectra collected by pulsed neutron instrument disposed down a wellbore traversing the formation, the spectra including capture interactions and inelastic interactions; deconvolving the spectra to estimate an elemental yield; converting the elemental yield to a total concentration value; subtracting a concentration value for drilling mud and a concentration value for the formation from the total concentration value to estimate a concentration in fluid within the formation; and converting the fluid concentration value to a resistivity value. A computer program product and an instrument are provided.

Abstract: A method of estimating formation porosity using a neural network for neutron porosity tools. In the training stage, the near-to-far ratio, environmental variables, such as mineralogy, borehole size, standoff etc., are fed to the inputs and the neural network is trained for obtaining the related true porosity (the output).

Abstract: Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From only the elemental analysis and measurements of porosity, density and natural gamma rays, an estimate of the mineralogy of the formation is made treating the problem as one of minimizing a quadratic objective function subject to equality and/or inequality constraints.

Abstract: The invention concerns a method for determining the porosity of an earth formation penetrated by a borehole. The method comprises conveying a tool along said borehole, wherein the tool comprises a source of neutron radiation and at least two detectors axially spaced from said source at at least two different spacings. At least one near detector and at least one far detector are selected and a correction computed. The porosity of the earth formation is determined by correcting the far detector porosity with the computed correction.

Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating formation properties using nuclear radiation, particularly an apparatus and method for estimating bulk density of a formation. The method may include using gamma ray count rate information to model bulk density. The method may include using time-dependent ratios with a pulsed radiation source. The method may also include dividing gamma ray information by time and/or by energy window. The apparatus includes a processor and storage subsystem with a program that, when executed, implements the method.

Abstract: A method for analyzing formation data includes decomposing the formation data into simple components that can be used to reconstruct the formation data, wherein the decomposing is performed at a first location and includes a process to minimize an overlap between the simple components; and transmitting parameters representing the simple components to a second location for reconstructing the formation data. A system for analyzing formation data that includes a processor and a memory that stores a program having instructions for decomposing the formation data into simple components that can be used to reconstruct the formation data, wherein the decomposing is performed at a first location and includes a process to minimize an overlap between the simple components; and transmitting parameters representing the simple components to a second location for reconstructing the formation data.

Abstract: The present disclosure relates to apparatus and methods for evaluating an earth formation through a drillstring during tripping of the drillstring. The apparatus may include a logging instrument including a formation evaluation sensor configured to be dropped or pumped into a drillstring at the end of drilling. The logging instrument may be configured to make measurements through a homogenous portion of the drillstring while the drillstring is being tripped. The apparatus may include a memory and processor for logging data for later retrieval. The method may include making at least one measurement indicative of a property of an earth formation using a sensor operatively associated with a logging instrument, wherein the logging instrument is conveyed to proximate to a homogeneous portion of a drilling tubular using the drilling tubular.

Abstract: A method for estimating a distribution of pore sizes of a fluid filled rock formation penetrated by a borehole, the method includes: processing nuclear magnetic resonance (NMR) data to determine a distribution of diffusion coefficients and a distribution of relaxation time constants for at least one depth in the borehole; plotting the distribution of diffusion coefficients and the distribution of relaxation time constants as a cross-plot for the at least one depth; identifying a water line on the cross-plot, each point on the water line having substantially the same value for the diffusion coefficient; and estimating the distribution of pore sizes from the distribution of relaxation time constants plotted along the water line.

Abstract: Processing gamma count rate decay curves using neural networks. At least some of the illustrative embodiments are methods comprising obtaining a gamma count rate decay curve one each for a plurality of gamma detectors of a nuclear logging tool (the gamma count rate decay curves recorded at a particular borehole depth), applying the gamma count rate decay curves to input nodes of a neural network, predicting by the neural network a geophysical parameter of the formation surrounding the borehole, repeating the obtaining, applying and predicting for a plurality of borehole depths, and producing a plot of the geophysical parameter of the formation as a function of borehole depth.

Abstract: Pulse sequences are applied to a fluid in an earth formation with an external static magnetic field and NMR spin echo signals are obtained. The received NMR signals are affected by internal field gradients due to a contrast in magnetic susceptibility between the grains of the formation matrix and the fluid in the pore space. Processing of the data gives the relaxation time and diffusivity of the fluid.

Abstract: A method for determining fracture geometry of a subterranean formation from radiation emitted from a fracture in the formation, including measuring gamma-radiation emitted from the fracture; subtracting background radiation from the measured gamma-radiation to obtain a peak-energy measurement; comparing the peak-energy measurement with a gamma-ray transport/spectrometer response model; and determining formation fracture geometry of the fracture in accordance with values associated with the response model.

Abstract: Example methods and apparatus to determine phase-change pressures are disclosed. A disclosed example method includes capturing a fluid in a chamber, pressurizing the fluid at a plurality of pressures, measuring a plurality of transmittances of a signal through the fluid at respective ones of the plurality of pressures, computing a first magnitude of a first subset of the plurality of transmittances, computing a second magnitude of a second subset of the plurality of transmittances, comparing the first and second magnitudes to determine a phase-change pressure for the fluid.

Abstract: There is provided a monitoring system (300) for monitoring within a borehole (10). The system (300) comprises a probe assembly (100) operable to be moved within the borehole (10) for sensing one or more physical parameters therein, a data processing arrangement (110) located outside the borehole (10), and a data communication link (120) operable to convey sensor data indicative of the one or more physical parameters from the probe assembly (100) to the data processing arrangement (110) for subsequent processing and display and/or recording in data memory (140). The probe assembly (100) includes one or more sensors (320) for spatially monitoring within the borehole (10) and generating corresponding sensor signals (360).

Abstract: A downhole tool and method for determining a parameter of a formation as a function of radial distance from the borehole into the formation. The tool comprising a nuclear source for irradiating the formation and a plurality of sensors each independently measuring a density of the formation at a different radial depth into the formation. A processor combines the density measurements for determining the parameter of the formation as a function of radial distance.

Abstract: A subsurface reservoir may be characterized and/or monitored based on fluid injection. For example, fluid may be injected into the reservoir, and data (e.g., seismic data, geodetic data, pressure data) relating to the injected fluid in the reservoir may be used to identify characteristics of the reservoir and/or to monitor the injected fluid in the reservoir. In some aspects, air or another type of surrogate fluid is injected into the reservoir, and the reservoir's viability as a carbon dioxide sequestration site can be analyzed based on response data collected from the reservoir. In some aspects, carbon dioxide is sequestered in the subsurface reservoir, and three-dimensional geodetic response data is collected and used to monitor and/or facilitate quality control.

Abstract: A downhole tool and method for determining properties of a formation. The method comprising irradiating the formation with a nuclear source; performing both a resistivity and a sigma measurement at each of different radial depths into the formation with a plurality of detectors; and inputting the measurements into a predetermined model for determining the properties of the formation.

Abstract: Methods and systems are provided for evaluating petrophysical properties of subterranean formations and comprehensively evaluating hydrate presence through a combination of computer-implemented log modeling and analysis. Certain embodiments comprise the steps of running a number of logging tools in a wellbore to obtain a variety of wellbore data and logs, and evaluating and modeling the log data to ascertain various petrophysical properties. Examples of suitable logging techniques that may be used in combination with the present invention include, but are not limited to, sonic logs, electrical resistivity logs, gamma ray logs, neutron porosity logs, density logs, NRM logs, or any combination or subset thereof.

Abstract: The online measurement system of radioactive tracers in oil wells head, object of this invention, is characterized by the use of new technology to measure concentrations of tracer activity in real time, using a radiation detector NaI (TI), with features that make it possible to detect up to three different tracers and be able to operate in temperature conditions up to 150° C., which allows to be immersed in a container with fluid coming from the flow stream, achieving with this to increase the sensitivity of the measurements. This system of measurement in the head of production wells will allow having much more data of the tracer activity, avoiding having to transport the operational staff to production wells to carry out sampling test, with all the advantages that this represents.

Abstract: An instrument for performing measurements downhole includes: at least one gamma-ray detector with azimuthal sensitivity equipped for discriminating energy of incident gamma-rays. This instrument is equipped with or without a neutron or gamma-ray source. A method and computer program product providing the azimuthal sensitivity of the instrument is provided.

Abstract: The disclosure is directed to methods and apparatuses for estimating a response relating to a formation by stressing a wall of a borehole during either wireline or while drilling deployment. The response may be estimated by stressing the wall of a borehole formed in the formation; and estimating a response of the borehole wall to the stress. The response may be estimated using a force module configured to induce the stress around borehole and a tool configured to estimate the response of the borehole wall to the stress.

Abstract: A method for estimating a concentration of carbon dioxide (CO2) in a formation penetrated by a borehole, the method includes: conveying a carrier through the borehole; irradiating the formation with neutrons from a neutron source disposed at the carrier; detecting photons from the formation resulting from the irradiating; and estimating the concentration of CO2 from data acquired from the detecting.

Abstract: A method for estimating a lithotype of an earth formation, the method includes: obtaining at least two different energy spectra of radiation received from the earth formation using the logging tool, each energy spectrum having at least one of a natural gamma-ray spectrum, a fast neutron-induced inelastic spectrum, and a thermal neutron induced capture spectrum; establishing at least one geochemically-based constraint related to elemental spectral yields to be determined; determining the elemental spectral yields from the at least two different energy spectra by decomposing the at least two different energy spectra over weighted sum of monoelemental standards wherein at least one weight is constrained by the at least one geochemically-based constraint and each weight represents a proportion of one monoelemental standard; converting the elemental spectral yields to elemental concentrations; and using a classifier to receive the elemental concentrations as input and to provide a lithotype as output.

Abstract: A method for processing well logging data includes method dividing the well logging data into a number of constant dimensional effect segments, where each constant dimensional effect segment defines an interval having a similar dimensional effect on the log response. The well logging data is taken from a highly deviated well, which may include portions deviated at greater than 90-degrees. The method further includes dividing the constant dimensional effect segments into a number of constant property intervals, each constant dimensional effect segment including at least one corresponding constant property interval, and each constant property interval defining a wellbore distance over which a formation property is substantially constant that results in a log response having a low variance. The method further includes providing the constant property intervals to an output device.

Abstract: Determining a value indicative of gas saturation of a formation. At least some of the illustrative embodiments are methods including obtaining an inelastic count rate and a capture count rate of a gamma detector for a particular borehole depth, calculating a ratio of an inelastic count rate to a capture count rate for the particular borehole depth, determining a value indicative of gas saturation based on the ratio of the inelastic count rate to the capture count rate for the particular borehole depth, repeating the obtaining, calculating and determining for a plurality of borehole depths, and producing a plot of the value indicative of gas saturation of the formation as a function of borehole depth.

Abstract: Methods and related systems are described for predicting a response of a gamma ray measurement tool located in a borehole surrounded by a subterranean formation. A response of the tool is calculated according to one or more properties at a plurality of spatial locations in relation to the measurement tool using a forward model that assumes a non-linear relationship between the one or more properties at the plurality of spatial locations and the corresponding response of the tool.

Abstract: Formation fluid salinity is an important parameter in water saturation and formation porosity measurements. Systems and methods are disclosed herein to provide accurate water saturation and/or formation porosity measurements in the presence of unknown or highly variable salinity levels. Some logging tool assembly embodiments include a resistivity tool and an augmented neutron porosity tool. The neutron porosity tool is augmented with a gamma ray detector configured to measure the rate at which hydrogen nuclei capture neutrons from a neutron source. A processing system coupled to the logging tool assembly provides a salt compensated formation porosity log and/or a water saturation log. The logging tool assembly can also include a density logging tool and a natural gamma ray logging tool to provide a salt independent triple-combo log.

Abstract: Apparatus, systems, and methods may operate to receive interacted energy at an optical calculation device attached to a down hole housing to be deployed in a down hole environment. Further activities may include optically compressing data carried by the interacted energy into at least one orthogonal component, using the optical calculation device, sending a signal associated with the at least one orthogonal component to a remote surface computer, and determining a property of petroleum located in the down hole environment using the remote surface computer, based on the signal. The optical calculation device may comprise a multivariate optical element (MOE). Additional apparatus, systems, and methods are disclosed.

Abstract: Systems and methods in which data compression techniques are utilized to fill a predetermined channel capacity are shown. According to one configuration, event data points within test data are selected for communication via the data communication channel and a data decimator is utilized to identify other data points within the test data to fill or substantially fill the predetermined channel capacity. The foregoing data decimator may employ one or more variables for selecting data for communication, wherein one or more of the variables are preferably adjusted in decimator iterations to select an optimum or otherwise desirable subset of data for communication. Data decimators may additionally or alternatively implement a suitable “growth” function to select the particular data for communication and/or the amount of data communicated.

Abstract: A method and system for determining a property of a sample of fluid in a borehole. A fluid sample is collected in a downhole tool. While collecting, X-rays are transmitted proximate the fluid from an X-ray source in the tool and an X-ray flux that is a function of a property of the fluid is detected. The detected X-ray flux data is processed to determine the property of the fluid.

Abstract: Elemental analysis of an earth formation is performed using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the mineralogy of the formation is made. A prediction of the capture cross-section of the formation is made using the mineralogical analysis. The difference between the predicted capture cross-section and a measured capture cross-section is an indication of gas in the formation.

Abstract: A gamma ray detector uses a scintillation detector having a response that matches a response characteristic of a photodiode. The detector may be used to measure natural gamma rays and/or gamma rays produced by interaction of neutrons from a neutron source with the earth formation.

Abstract: Systems and methods which provide modeling or simulation of gamma ray (GR) tool response using a hybrid analytical and numerical technique are shown. Embodiments employ a GR tool simulation technique which provides gamma ray information simulated as a function of only the gamma particles which reach the detector without scattering. Embodiments utilize a discretization function to determine the gamma particles which would reach a point detector from each unit volume source of an investigation domain without scattering. Embodiments further utilize the foregoing discretization function with respect to a plurality of point detectors, wherein the particular number and configuration of point detectors are selected to relatively accurately simulate the results of a particular GR detector configuration, such as line detector or volume detector configurations.

Abstract: A multicomponent induction logging tool is used on a MWD bottomhole assembly. Multifrequency focusing that accounts for the finite, nonzero, conductivity of the mandrel is applied. Using separation of modes, the principal components and relative dip angles in an earth formation are determined. The results are used for reservoir navigation in an earth formation.