Abstract: Disclosed is a method for detecting a pair of opposing breakouts in a borehole penetrating an earth formation. The method includes: conveying a downhole tool configured to perform measurements of a property of the earth formation; producing an image of the earth formation from the measurements, the image comprising a plurality of sectors; dividing the sectors into radial segments, each segment corresponding to an opposite segment; rotating the segments at least one sector at a time until a specified angle is achieved; calculating an average value for the measurements associated with each segment for each rotation of the segments; stacking the average values for opposing segments to produce stack values; determining a maximum or minimum stack value; determining if the maximum or minimum stack value exceeds a threshold value; and detecting the first breakout and the second breakout if the maximum or minimum stack value exceeds the threshold value.

Abstract: A method for estimating a property of an earth formation, the method includes: conveying a carrier through a borehole penetrating the earth formation; performing a measurement of total organic carbon (TOC) within a region of investigation in the earth formation using a logging tool disposed at the carrier; and correlating the measured TOC to the property to estimate the property.

Abstract: A method for estimating a property of an earth formation penetrated by a borehole.

Abstract: A method for electromagnetic surveying subsurface formations includes inducing an electromagnetic field in the subsurface formations by passing electric current through a transmitter. Response of the subsurface formations to the induced electromagnetic field is detected at a first plurality of spaced apart positions disposed longitudinally within a bipole length of the transmitter. A direct induction response is removed from the detected response.

Abstract: A computer system and computer implemented method for automatically identifying a hydrocarbon (such as kerogen, gas, oil) rich zone in a well bore includes obtaining well log data comprising neutron data, density data, radioactivity data, and resistivity data representative of physical characteristics of a formation surrounding the well bore and computing an apparent neutron porosity and an apparent density porosity based on the neutron data and density data. A normalized neutron-density separation is computed based on the computed apparent neutron porosity and the computed apparent density porosity and a baseline of the formation is determined for each data type. Using the computed normalized neutron-density separation, the radioactivity data, the resistivity data, and the determined baselines, the presence or absence of a hydrocarbon rich zone is determined. A quality index may further be derived from the data.

Abstract: A method of inverting induction logging data for evaluating the properties of underground formations surrounding a borehole, the data including induction voltage measurements obtained from a tool placed close to the formations of interest, the method includes: (a) defining a relationship relating the induction voltage to wave number, dielectric permittivity and conductivity; defining a cubic polynomial expansion of the relationship; and solving the cubic polynomial relationship using the voltage measurements to obtain values for conductivity that includes skin-effect correction, and apparent dielectric permittivity; and (b) using the obtained values for conductivity and apparent dielectric permittivity to derive a simulated value of induction voltage; determining the difference between the simulated value of the induction voltage and the measured induction voltage; and iteratively updating the values of conductivity and dielectric permittivity used for the derivation of the simulated value of induction voltag

Abstract: A transmitter on a bottomhole assembly (BHA) is used for generating a transient electromagnetic signal in an earth formation. A processor estimates the distance to a resistivity interface using a signal produced by a receiver on the BHA. The transmitter-receiver distance may be less than 1 m. The estimation of the distance is done in real time using a thin conductive sheet approximation.

Abstract: A method for determining resistivity distribution of formations below a bottom of a body of water from transient electromagnetic signals acquired by imparting a transient electromagnetic field into the water and detecting an electromagnetic response thereto at a plurality of spaced apart positions from a place of the imparting includes simulating an air wave response at each of the plurality of spaced apart positions. The simulated air wave response is subtracted from the detected response to produce a subsurface impulse response at each of the plurality of positions. The subsurface impulse responses are used to determine the resistivity distribution.

Abstract: A method of analyzing characteristics of a subterranean formation includes applying a wavelet transform to measured data or to derived data obtained from the measured data, the measured data obtained by measuring a physical property at each of a plurality of positions in a borehole that penetrates the subterranean formation; selecting one or more scales for analyzing wavelet coefficients; performing a segmentation of the data; calculating a distribution of wavelet coefficients for each scale, for one or more spatial directions of wavelet transform application, for the wavelet transform of the data and for each segment that belongs to the portion on which the wavelet transform has been calculated; and for each segment, analyzing a distribution of the data and the distribution of the wavelet coefficients for each scale in terms of their overlap with corresponding distributions of training samples to produce a geological interpretation of the subterranean formation.

Abstract: A system and a method for estimating a model of a geological formation are provided. The geological formation has a wellbore extending therethrough. The method includes obtaining a first resistivity log associated with the geological formation from a LWD sensor in the wellbore. The method further includes obtaining a second resistivity log associated with the geological formation from a WL sensor in the wellbore. The method further includes calculating a plurality of horizontal resistivity values associated with the geological formation by utilizing a first inversion technique and the first resistivity log. The method further includes obtaining a plurality of invaded zone resistivity values obtained from a micro-resistivity measurement device in the WL sensor. The method further includes calculating a plurality of invaded zone thickness values proximate the wellbore by utilizing a second inversion technique and the second resistivity log.

Abstract: Methods and apparatus for estimating stress characteristics of formations. The method comprises: (a) acquiring sonic anisotropy data, image data or both associated with at least one borehole (b) employing sonic anisotropy data to estimate fast shear direction (FSA) to extract FSA observed data; (c) computing FSA from forward modeling, forward modeling utilizes a first deviatoric stress tensor to extract FSA predicted data; (d) computing FSA misfit from difference between FSA observed data and FSA predicted data to obtain computed FSA misfit relating to first deviatoric stress tensor; (e) if computed FSA misfit is equal to or less than a defined value, then store computed FSA misfit, otherwise repeat steps (d)-(h) using another deviatoric stress tensor so a different deviatoric stress tensor is used for each repeat; (f) selecting smallest stored computed misfit from group consisting of stored computed FSA misfit, at least one other stored computed misfit or combination thereof.

Abstract: An apparatus, method and computer-readable medium for estimating a resistivity property of an earth formation in a borehole filled with oil-based mud. The method includes conveying a logging tool into a borehole; measuring a plurality of impedance values of the earth formation, each of the plurality of impedance values being obtained at one of a plurality of measure electrodes on the logging tool; determining a coefficient related to an electrical property of the mud from a plurality of pairs of impedance values; estimating the resistivity property of the formation from the determined coefficient; and recording the resistivity property on a suitable medium.

Abstract: Measurements made by a multi-component logging tool in a borehole are inverted to obtain three principal resistivities (or conductivities) and three associated angles of a bi-axially symmetric formation traversed by the borehole.

Abstract: Certain embodiments described herein provide a measure of the misalignment of multiple acceleration sensors mounted in the downhole portion of a drill string. In certain embodiments, the measure of the misalignment corresponds to a measure of sag which can be used to provide an improved estimate of the inclination of the downhole portion of the drill string and/or the wellbore. Certain embodiments described herein provide an estimate of the magnetic interference incident upon a drilling system using multiple magnetic sensors mounted within a non-magnetic region of the downhole portion of the drilling system. Certain embodiments utilize the magnetic measurements to determine an axial interference resulting from one or more magnetic portions of the downhole portion and to provide an improved estimate of the azimuthal orientation of the downhole portion with respect to the magnetic field of the Earth.

Abstract: A method for modeling material behavior includes using empirical three dimensional non-uniform stress and strain data to train a self-organizing computational model such as a neural network. A laboratory device for measuring non-uniform stress and strain data from material includes an enclosure with an inclusion in it. As the enclosure is compressed, the inclusion induces a non-uniform state of stress and strain. A field testing device includes a body having a moveable section. When the body is inserted in a material and the moveable section moved, a non-uniform state of stress and strain can be characterized.

Abstract: A method of normalizing well log data relating to geology of a subsurface region includes identifying a pair of markers defining a zone on each well log, determining a statistic for a property within the zone for each well log, fitting a smooth function to the statistics to create a first-iteration trend surface, determining, for each statistic, a deviation from the trend surface and eliminating those statistics that deviate from the trend surface by greater than a threshold value, fitting a smooth function to the remaining statistics to create a second-iteration trend surface, normalizing the property for each well log based on the second-iteration trend surface, and analyzing the normalized properties to determine the geology of the subsurface region.

Abstract: A method for determining movement of a fluid contact in a subsurface reservoir includes measuring azimuthally sensitive resistivity at a first time from within a wellbore penetrating the subsurface reservoir. A first position of the fluid contact with respect to the wellbore is determined using the azimuthally sensitive resistivity measurements. After a selected time, the measuring azimuthally sensitive resistivity from within a wellbore penetrating the subsurface reservoir is repeated. Movement of the fluid contact from the first position is determined using the repeated azimuthally sensitive resistivity measurements.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. This invention also relates to a method and apparatus for steering a downhole tool during a drilling operation in order to maintain the borehole within a desired earth formation.

Abstract: A method, system and computer program product for determining permeability of an earth formation of a reservoir are disclosed. A method may include: providing formation testing data of the earth formation; defining layering of the earth formation; determining a geological model for each layer; modeling pressure transient in the earth formation by representing pressure transient within a layer using an analytical solution and representing pressure transient between two layers using a numerical solution, the analytical solution selected based on at least one of the respective geological model and data regarding a drilled well of the reservoir, and a parameter of the analytical solution and a parameter of the numerical solution being determined based on the formation testing data; and determining the permeability of the earth formation based on the pressure transient model.

Abstract: A probabilistic method for classifying observed CSEM response for a resistive anomaly to classify the response into multiple geologic categories indicative of hydrocarbon production potential. Each category is assigned a prior probability (301). For each category, conditional joint probability distributions for observed CSEM data in the anomaly region are constructed (303) from rock property probability distributions (302) and a quantitative relationship between rock/fluid properties and the CSEM data (304). Then, the joint probability distributions and prior probabilities for each category (305) are combined with observed data (307) and used in Bayes' Rule (306) to update the prior category probabilities (308). Seismic data may be used to supplement CSEM data in the method.

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 a direction of a conductivity tensor are determined. The results are used for reservoir navigation in earth formations. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Measurements made by a multi-array/multi-frequency induction resistivity logging tool in a borehole are used for determining the length of fractures in an earth formation and the resistivity of the unfractured formation when the fractures have a resistive fluid. A look-up table based on modeling of a fracture by a pair of wings is used.

Abstract: A method for managing a fracturing operation. In one implementation, the method may include positioning one or more sources and one or more receivers near a hydrocarbon reservoir; pumping a fracturing fluid into a well bore of the hydrocarbon reservoir; performing a survey with the sources and the receivers during the fracturing operation; comparing the baseline survey to the survey performed during the fracturing operation; analyzing one or more differences between the baseline survey and the survey performed during the fracturing operation; and modifying the fracturing operation based on the differences.

Abstract: A downhole acoustic logging tool is used for generating a guided borehole wave that propagates into the formation as a body wave, reflects from an interface and is converted back into a guided borehole wave. Guided borehole waves resulting from reflection of the body wave are used to image a reflector.

Abstract: A method for processing magnetotelluric data to identify subterranean deposits is provided for. The data comprise the amplitude of alternating magnetic or electrical fields recorded over time in at least two vector components at one or more locations in an area of interest. Amplitude pulses are identified in the data, wherein the pulses are time segments comprising an amplitude peak meeting defined threshold criteria in at least one vector component. The pulses are filtered at a set of predetermined frequencies to separate amplitude data at each frequency from the remainder of the amplitude data in the pulses. The frequencies correspond to subterranean depths over a range of interest. Differential impedances ?Z of the pulses at each frequency at each location are then statistically analyzed to determine a value correlated to the resistance of the earth at each frequency. The resistance values are indicative of the presence or absence of deposits at the corresponding subterranean depth at the location.

Abstract: Disclosed herein is a method of measuring a resistivity parameter of an earth formation. The method includes: applying a first electric measurement current including a first series of pulses to a first electrode and inducing a first formation current in the earth formation; applying a second electric measurement current including a second series of pulses to a second electrode and inducing a second formation current in the earth formation, the first series of pulses and the second series of pulses occupying distinct portions of a time domain in a selected time window; measuring the first measurement current, the first formation current, the second measurement current and the second formation current by coherent in-phase demodulation; and calculating at least one resistivity parameter by i) comparing the first measurement current to the first formation current and ii) comparing the second measurement current to the second formation current.

Abstract: A method of evaluating an earth formation is disclosed which includes conveying a logging tool into a borehole in the earth formation and using the logging tool to obtain a first set of azimuthally-independent resistivity measurements of the earth formation and a second set of azimuthally-sensitive resistivity measurements of the earth formation and estimating a value of a property of the earth formation using the first set of measurements and the second set of measurements, the estimation being substantially unaffected by a displacement of the logging tool from a center of the borehole.

Abstract: A three-coil bucking system is used for determination of a formation resistivity property ahead of the drill bit. The conductive drill pipe is provided with non-conductive inserts in the proximity of at least one transmitter and at least two receivers. Transient electromagnetic signals are processed to give the estimate of the resistivity property and for geosteering.

Abstract: An apparatus, method and computer-readable medium for imaging an earth formation. A downhole assembly having a resistivity sensor is conveyed in a borehole penetrating the earth formation. The resistivity sensor includes a plurality of antenna coils arranged along a radial line that is substantially perpendicular to a longitudinal axis of the downhole assembly and configured to obtain measurements of a resistivity property of the earth formation. A processor images the earth formation using the obtained measurements.

Abstract: A transform function is useable to map a characteristic (e.g., acoustic impedance, shear impedance, density, and/or other characteristic) to a mechanical property (e.g., Young's modulus or other mechanical property). Values of the characteristic can be derived based on surface survey data, and such values can be mapped to respective values of the mechanical property using the transform function.

Abstract: Logging tools, methods, and computer programs for use in borehole logging are described. The logging tool includes three or more tensors, each tensor including one or more coils. Each coil is characterized by coil parameters including an axis orientation, a cross-sectional area, a number of turns, and a location. At least one of the coil axes is disposed at an angle to the borehole axis. One or more of the coil parameters are selected to minimize sensitivity to borehole current.

Abstract: A method is provided for determining formation resistivity, anisotropy and dip from wellbore measurements includes moving a well logging instrument through subsurface formations. The instrument includes longitudinal magnetic dipoles and at least one of tilted and transverse magnetic dipoles. Formation layer boundaries and horizontal resistivities of the formation layers are determined from longitudinal magnetic dipole measurements. Vertical resistivities of the formation layers are determined by inversion of anisotropy sensitive measurements. Improved vertical resistivities of the formation layers and dips are determined by inverting symmetrized and anti-symmetrized measurements. Improved vertical resistivities, improved boundaries and improved dips are determined by inversion of the all dipole measurements. Improved horizontal resistivities, further improved layer boundaries and further improved dips are determined by inversion of all dipole measurements.

Abstract: A method of event-based power management for seismic sensors is disclosed. The method comprises measuring seismic activity with a seismic sensor and comparing the measured seismic activity from the seismic sensor against at least one criteria. When the measured seismic activity does not satisfy the at least one criteria, a signal processing circuit is maintained in a deactivated state. When the measured seismic activity satisfies the at least one criteria, the signal processing circuit is activated to analyze the measured seismic activity. The signal processing circuit enters a functional mode based on analyzing the measured seismic activity.

Abstract: Methods and apparatus are provided for receiving, detecting and transmitting geophysical data from a plurality of electrodes placed in the soil utilizing a dynamically reconfigurable wireless control unit that is located on each electrode. Data from the control units is transmitted by a wireless signal to a centralized data processor for analysis. Control data is provided from a central control processor to the control unit by wireless transmission. The control unit, which is positioned, includes a multi-channel radio frequency transmitter/receiver and a processor to actuate relays and record data returns from the measured substrate soil for transmission to the central data processor. The control unit incorporates a changeable code or address to unambiguously identify itself, and its spatial relationship to other electrodes, to the central data processor and the central control processor.

Abstract: Method for generating a three-dimensional resistivity data volume for a subsurface region from an initial resistivity model and measured electromagnetic field data from an electromagnetic survey of the region, where the initial resistivity model is preferably obtained by performing multiple ID inversions of the measured data [100]. The resulting resistivity depth profiles are then registered at proper 3D positions [102]. The 3D electromagnetic response is simulated [106] assuming the resistivity structure is given by the initial resistivity model. The measured electromagnetic field data volume is scaled by the simulated results [108] and the ratios are registered at proper 3D positions [110] producing a ratio data volume [112]. A 3D resistivity volume is then generated by multiplying the initial resistivity volume by the ratio data volume (or some function of it), location-by location [114]. A related method emphasizes deeper resistive anomalies over masking effects of shallow anomalies.

Abstract: A method for determining a list of survey points for a drilling well includes a feedback loop in which one or more measured parameters are compared with computed or derived parameters. The computed parameters are typically obtained from other/additional measurements. For example, in one exemplary embodiment of the invention, a magnetic least distance vector determined via magnetic ranging is compared with a geometric least distance vector computed from conventional borehole surveying measurements. Estimates of the drilling well azimuth and/or inclination may be adjusted to yield a good agreement between the magnetic and geometric least distance vectors. Exemplary embodiments of the present invention advantageously provide for a substantially real-time determination of a definitive well path for a drilling well as well as a substantially real-time relative placement of the drilling well with respect to a target well.

Abstract: A computer-implemented method of characterizing elastic properties of a subsurface formation at various fluid saturation conditions is disclosed.

Abstract: A logging-while-drilling system for efficiently providing a reliable measurement of various petrophysical properties of subsurface earth formations.

Abstract: A method of determining the effect of formation porosity on formation resistivity and parameters derived from the formation resistivity is described, including the step of determining for a depth interval a heterogeneity measure; and using a pre-defined relation to transform the heterogeneity measure into an algebraic term determining the effect of the formation porosity on the formation resistivity, based for example on Archie's law or similar relations.

Abstract: A series of scans is generated for a subsurface and a derivative image is created using the series of subsurface images. One or more tests are performed on the derivative image, and a subsurface object is detected based on the one or more tests. A sensor is configured to generate a series of scans for a subsurface and a processor is coupled to the sensor. The processor is configured to execute stored program instructions that cause the processor to generate a series of images of the subsurface using the series of scans, create a derivative image using the series of subsurface images, perform one or more tests on the derivative image, and detect a subsurface object based on the one or more tests.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. Although this invention is primarily intended for MWD or LWD applications, this invention is also applicable to wireline and possibly other applications.

Abstract: Characterizing a reservoir with electromagnetic imaging surveys includes normalizing measured voltage data by transmitter moment, sorting the normalized voltage data into common receiver profiles, densely resampling transmitter locations using common positions for the receiver profiles, coarsely resampling the data at discreet transmitter locations, defining a starting model for inversion, weighting the data by a factor, converting the normalized voltage data to ratios, calculating a conductivity image using a ratio inversion method, and verifying that an inversion has converged and the image is geologically reasonable. The image can then be displayed. The invention can be used for cross-well, surface-to-borehole, borehole-to-surface, and single-well (borehole-to-borehole) measurements measurements by which the effects of steel casing are reduced.

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: An orientation vector, referred to hereinafter as the “geosteering vector,” is directed to the more conductive formation area within the DOI of the tool and away from the more resistive formation areas. Accordingly, drilling in a direction opposite the geosteering vector leads to more resistive formation. Also, the disclosed geosteering vectors obtained from the real and imaginary components will not align with each other for non-planar formations and therefore the misalignment of the geosteering obtained from real and imaginary components is indicative of a non-planar formation. A superposition method is disclosed which can be used to calculate electromagnetic (EM) couplings in a non-planar geometry formation (as well as in a planar geometry formation) in real time, without requiring two or three dimensional modeling calculations.

Abstract: A method for determining permeability of a subsurface formation includes measuring a parameter related to fluid content of the formation at a first time from within a wellbore penetrating the formation. A rate of entry of fluid from the wellbore into the formation is determined from the measurement of the parameter made at the first time. The permeability is determined from the rate of entry.

Abstract: A method for analyzing a formation, that includes plotting resistivity data points on a resistivity graph to obtain plotted resistivity data points, and selecting a first shale point on the resistivity graph based on the plotted resistivity data points. The first shale point represents a resistivity anisotropy of shale in the formation. The method further includes generating, for each of a plurality of shale fraction values, a first shale fraction curve on the resistivity graph based on the shale fraction value and the first shale point, and generating, for each of a plurality of sand resistivity values, a first sand resistivity curve on the resistivity graph based on the sand resistivity value and the first shale point. A hydrocarbon yielding region in the formation is identified based on the first sand resistivity curves and the first shale fraction curves.

Abstract: Methods and apparatus to process measurements associated with drilling operations are described. An example method of modifying processing results during a subterranean formation drilling operation includes identifying a plurality of parameters and processing measurements associated with the subterranean formation obtained while drilling and the plurality of parameters to generate first results. Additionally, the example method includes processing measurements associated with the subterranean formation obtained while drilling is temporarily suspended and the plurality of parameters to generate second results and comparing the first and second results. Further, the example method includes, in response to the comparison of the first and second results, modifying the first results based on the second results to improve a quality of the first results.

Abstract: A wellbore tool for optimizing magnetic signals is provided. The wellbore tool has a tool body and an electric current driving device with an insulated gap on the downhole tool body. The electric current driving device generates electric current across the gap. The wellbore tool has a a magnetometer capable of measuring a magnetic field.

Abstract: A method for mapping sub-surface resistivity contrasts comprising making multi-channel transient electromagnetic (MTEM) measurements using at least one electric source with grounded input current electrodes or one magnetic source with current in a wire loop or multi loop and at least one electric field or magnetic field receiver, measuring the resultant earth response simultaneously at each receiver using a known recording system, measuring the system response by measuring directly the current in the wire at the source using effectively the same recording system, using the measured system response to recover the impulse response of the earth from each measured earth response, and creating from such impulse responses a sub-surface representation of resistivity contrasts.

Abstract: This invention is directed to a downhole method and apparatus for simultaneously determining the horizontal resistivity, vertical resistivity, and relative dip angle for anisotropic earth formations. The present invention accomplishes this objective by using an antenna configuration in which a transmitter antenna and a receiver antenna are oriented in non-parallel planes such that the vertical resistivity and the relative dip angle are decoupled. Preferably, either the transmitter or the receiver is mounted in a conventional orientation in a first plane that is normal to the tool axis, and the other antenna is mounted in a second plane that is not parallel to the first plane. Although this invention is primarily intended for MWD or LWD applications, this invention is also applicable to wireline and possibly other applications.