Abstract: A method of estimating a parameter of a formation contacting a borehole with an instrument that includes a mandrel and a pad includes providing a measurement voltage to the pad; applying a biasing voltage to the mandrel while the measurement voltage is applied to the pad; measuring a received current during at least a portion of time the measurement voltage is provided; and estimating the parameter based on the received current.

Abstract: A system for and method of automatically evaluating similarity between a target geological region of interest and a plurality of known geological regions of interest includes selecting a plurality of quantitative parameters describing reservoir characteristics of the target geological region of interest and defining a graphical target line based on values of the selected parameters. Comparison lines are graphically constructed for at least some of the plurality of known geological regions of interest, respective comparison lines representing respective values of the quantitative parameters describing corresponding characteristics of respective regions among the known geological regions of interest. A similarity factor between each of the comparison lines and the target line is calculated based on the plotted target and comparison lines. The comparison lines are ranked based on the calculated similarity factors, and similarity factor versus similarity rank are graphically displayed.

Abstract: The present disclosure relates to an apparatus and method for estimating a parameter of interest of a downhole fluid using a fluid analysis module. The fluid analysis module may include: at least one nano element and a processor configured to estimate an impedance of the at least one nano element. The fluid analysis module may include an AC power supply configured to supply electrical signals at a plurality of frequencies through the at least one nano element. The method may include bringing the downhole fluid into contact with the at least one nano element; supplying electrical signals through the at least one nano element at a plurality of frequencies; generating impedance information for the at least one nano element in response to the electrical signals; and estimating the at least one parameter of interest using the impedance information.

Abstract: This disclosure relates to apparatuses and methods for reducing current leakage between a measure electrode and a logging tool body during borehole investigations in an earth formation involving electric current and non-conductive drilling fluid. The apparatus may include one or more transmitters disposed on a pad body, configured to inject an electric current into the earth formation, and coupled to the mandrel and one or more measure electrodes. The measure electrodes may be configured to receive current from the formation and coupled to a back plate of the pad body. The apparatus may be configured to maintain a selected ratio between pad body to logging tool body impedance and transmitters to logging tool body impedance sufficient to reduce current leakage between the earth formation and the logging tool body. The transmitter/mandrel and measure electrode/back plate may be electrically isolated from one another. The method may include using the apparatus.

Abstract: A method of passive surveying comprises generating one or more detected signals by passively detecting a signal generated within a subsurface earth formation due to a seismoelectric response or an electroseismic response in at least one porous subsurface earth formation containing at least one fluid, and processing the one or more detected signals to determine at least one property of the subsurface earth formation.

Abstract: Apparatus and methods for determining the rock solid (matrix) dielectric permittivity for subterranean rocks, such as carbonate rocks, are described. According to some embodiments, this is accomplished by linking the matrix permittivity to the detailed chemical composition of the rock. The linking function is defined by coefficients for each component that can be determined by inversion in a laboratory calibration process such that the function compensates for the permittivity contribution of rock components that may be undetectable through downhole logging procedures.

Abstract: A compensated ensemble crystal oscillator clock system. The clock system includes preferably four quad compensated clocks, a compensated temperature sensor, and software for processing and correcting system response. Physical fabrication of elements of the quad compensated clocks, the compensated temperature sensor and cooperating software minimized drift in frequency of the oscillator clock system in harsh borehole environments encountered while drilling a borehole. The clock system exhibits a frequency stability of 2.8×10?9 or less over a temperature range of from 0° C. to 185° C. The compensated ensemble crystal oscillator clock system is particularly applicable to seismic-while-drilling operations wherein precise downhole measurements of time are required typically over a period of days.

Abstract: A method and apparatus provide a time-dependent calibration to essentially eliminate pipe effect in pulse-induction logging while drilling. Use of two receivers to provide calibration and measurement information allows determination of formation properties in a downhole environment while eliminating the effect of tool effects.

Abstract: Impedances of an electromagnetic (EM) coil positioned in a well lined with an electrically conductive liner are determined. The impedances correspond to plural frequencies of operation of the EM coil. Based on the impedances of the EM coil corresponding to the plural frequencies, an attenuation factor associated with the electrically conductive liner is determined.

Abstract: A device is described for use as part of a system in which a transmitter is moved through the ground while transmitting a signal that can be used to locate the transmitter. The device includes a receiver for receiving the signal to generate certain information about the position of the transmitter relative to the position of the device based on the signal. A processor establishes a current location of the transmitter and records the current location as one of a series of recorded locations of the transmitter based on the certain information and, at a time of recording the current location, electronically records a time stamp that designates at least the time at which the current location was recorded as part of the series of recorded locations of the transmitter.

Abstract: An illustrative embodiment of a method is disclosed for assessing image quality of a down hole formation image, the method comprising collecting acquisition system data from a plurality of sensors down hole; applying a set of rules to the acquisition system data to obtain an acquisition quality indicator; and presenting the acquisition quality indicator at a surface location. A system is disclosed for performing the method.

Abstract: Methods and apparatus for detecting nearby conductors such as pipes, well casing, etc., from within a borehole. A nearby casing string can be detected by transmitting an electromagnetic signal from a transmit antenna on a downhole logging tool and measuring a parallel response signal with a first receive antenna parallel to the transmit antenna and a perpendicular response signal with a second receive antenna perpendicular to the transmit antenna, both receive antennas on the downhole logging tool. As the tool rotates, the transmitting and measuring are repeated to determine the azimuthal dependence of the parallel and perpendicular response signals. The azimuthal dependence is analyzed to determine a diagonal component of said azimuthal dependence for each response signal. Distance to a casing string can be estimated using the diagonal component of each response signal. At least one of the antennas is preferably tilted.

Abstract: Methods and systems for characterizing a formation are disclosed. A tool is placed in the formation. The tool comprises a perpendicular antenna set and a parallel antenna set. The perpendicular antenna set comprises at least one transmitter antenna oriented perpendicular to at least one receiver antenna and the parallel antenna set comprises at least one transmitter antenna oriented parallel to at least one receiver antenna. Data is obtained from the tool and used to determine a compensated geosignal for each of the perpendicular antenna set and the parallel antenna set. The determined compensated geosignal is used to characterize the formation.

Abstract: Measurements made with a multicomponent logging system oriented in a horizontal position above the surface of the earth must satisfy certain relationships. These relationships are used to establish calibration errors in the system.

Abstract: A method for determining the water saturation of an underground formation traversed by a borehole, the method composing: determining a first parameter (?) that is representative of the critical exponent of the electrical conductivity of the formation: determining a second parameter (Wc or Sc or ?c) that is representative of the formation percolation threshold; measuring a first set of formation properties; and combining, said first set of formation properties, first and second parameters in order to determine the water saturation (Sw) of said underground formation.

Abstract: An apparatus and method that provide steerable measurements of attenuation and phase difference are disclosed. In a preferred embodiment, a logging tool is provided with two triads of orthogonal receivers and a triad of orthogonal transmitters. A controller in the logging tool fires selected transmitters singly and in pairs, and determines measurements of ratios between signals received by the receiver triads. The measurement of sixteen ratios is sufficient to allow determination of attenuation and phase difference that would be measured by virtually steered receivers according to equations provided herein.

Abstract: Method for improving frequency-domain (1505), controlled-source electromagnetic data readability and interpretability in hydrocarbon prospecting by mapping a scaled amplitude or the relative amplitude (or phase) of the electromagnetic field in a scaled offset?scaled frequency plane (1510). The preferred mapping space uses the offset times the square-root of the frequency as the X-axis and the square-root of the frequency as the Y-axis. The preferred way to scale the amplitude of the electric field is to multiply it by the frequency to the power of ?1.5. Resistive anomalies in the data may be identified by comparing negative offset data (or data relative to a reference) to positive offset data (1515). The location and size of a potentially hydrocarbon-bearing resistive body may be estimated from the position of the anomaly on the map (1520).

Abstract: Method and apparatus for estimating a resistivity property of an earth formation in a borehole with oil-based drilling fluid. The method may include estimating the resistivity property using a sensitivity of a real part of a measured impedance to a reactance of a gap between a resistivity sensor and a borehole wall. The real component and the quadrature component of resistivity measurements made by a two-terminal imaging tool in a borehole having an oil-based mud are affected by the tool standoff. It is shown that the sensitivity of the real part of the resistivity measurement to the reactance of the gap can be estimated from the time derivatives of the two components of the measurements. This makes possible a principal component analysis of the data to give an improved image of the formation resistivity.

Abstract: A system for determining an invasion depth of an invaded zone surrounding a borehole while the borehole is being drilled includes a sensor configured to be disposed in a mud cake formed on a wall of the borehole and configured to measure a property of the mud cake and a computing device configured to receive a measurement from the sensor and determine the invasion depth based on the measurement.

Abstract: A method for estimating at least one formation parameter from a directional resistivity measurement includes computing a plurality of hypothetical directional resistivity values at a corresponding plurality of formation parameter values. The computation makes use of a forward model having at least one analytical expression that relates a directional resistivity measurement to the formation parameter. The analytical expression includes at least one image source term. Comparison of computed directional resistivity values with measured direct resistivity values enables a value of at least one formation parameter to be selected. The method may be implemented on a downhole processor.

Abstract: An efficient and cost-effective technique is provided to perform modeling of a reservoir in a subterranean structure. A compartment model of fluid compartments in a reservoir is generated, and based on the compartment model and a geomechanical model of the subterranean structure, movement of a ground surface due to volumetric change of the compartments is calculated. Satellite measurements of the ground surface are received over time, where the received satellite measurements of the ground surface over time indicate movement of the ground surface. The movement of the ground surface indicated by the received satellite measurements is compared with the calculated movement, and based on the comparing, one or more properties of the geomechanical model are adjusted.

Abstract: The present disclosure relates to a method to determine a volume of clearance surrounding a wellbore. A logging tool is provided. The logging tool may be disposed on a wireline, a drill string, or a wired drill pipe. A formation property is obtained using the logging tool. The formation property may include a voltage, a bulk resistivity, a horizontal resistivity, a vertical resistivity, a porosity, a permeability, a fluid saturation, an NMR relaxation time, a borehole size, a borehole shape, a borehole fluid composition, an MWD parameter, or an LWD parameter. The maximum depth of investigation into the subsurface formation is determined using a model response and a noise level, and the volume of clearance is determined using the determined maximum depth of investigation. The maximum depth of investigation and volume of clearance may be determined even though no boundary layers are detected.

Abstract: A method for determining a property of a fluid includes: receiving at a computing device an admittance spectrum created by application of an excitation to a resonator contacting the fluid, the spectrum covering a first frequency range and having real and imaginary components; determining a resonant frequency of the admittance spectrum, the resonant frequency being a frequency at which a magnitude of the imaginary component is about zero; determining a bandwidth of the spectrum; and determining the property based on one or both of the resonant frequency and the bandwidth of the resonant frequency.

Abstract: A method for determining the location of an underground sonde transmitter is disclosed. In some embodiments, the method includes measuring a set of complex electromagnetic field magnitude and phase strengths at one or more of positions while traversing a target sonde path at any angle using one or more electromagnetic coil sensors, modeling a set of expected complex electromagnetic strengths of a hypothetical sonde at the one or more of positions for one or more of the electromagnetic coil sensors, the set of expected electromagnetic field values corresponding to a model for the target sonde, and estimating parameters related to the target sonde based on the residual error between the measured set of complex electromagnetic field values and the modeled set of expected complex electromagnetic field strengths, wherein a final estimated parameter set is determined after the residual error has converged to a minimum tolerance.

Abstract: Methods of generating radial survey images of a borehole and methods of orienting downhole operational tools are disclosed. The disclosed techniques are used to generate a radial survey of the borehole in the form of one or more rose-plots and/or a radial image of the borehole and surrounding area that can be used to properly orient downhole operational tools in the desired direction. The tool string includes, from the top to bottom, a telemetry module, a non-rotating centralizer, a motor module, an imaging sonde used to survey the borehole, a rotating centralizer and a downhole operational tool. The motor module can be used to rotate the imaging sonde to generate the radial survey and then rotate the downhole operational tool to the desired direction based upon a review of the radial survey.

Abstract: The system and method provided modify a conventional seafloor long-wire electromagnetic (LEM) receiver by increasing the number of discrete antennae placed on the long wire. Two dipoles of electric field data are positioned exactly adjacent to each other, providing input to the same data logger system located within a seafloor survey unit to which the long wire is connected. Highly precise electric field gradients can be obtained by taking the difference of the measurements of the two electrodes, both for amplitude and phase. Any common-mode source of noise, such as magnetotelluric signals and receiver instrument noise will be rejected when the signals from the two electrodes are differenced. An acoustic navigation system utilizes a plurality of transponders to permit triangulation for accurate source-receiver ranging.

Abstract: A method for detecting formation resistivity outside of metal casing using time-domain electromagnetic pulse in a borehole, the method including steps of a) providing a borehole large power pulse transmitting source, recording an induced electromotive force ?, and full time digital recording a transmitted waveform and a received signal; b) conducting transmission-reception and superimposing received signals to improve signal to noise ratio; c) calculating corresponding casing response according to known casing parameters and recorded current waveform of the transmitting source to obtain a relative induced electromotive force ??f; d) correcting relative induced electromotive force value; e) carrying out one-dimensional inversion and converting the observation signal into radial variation information of the formation resistivity; f) obtaining a two-dimensional image of the longitudinal and radial resistivity distribution of outer cased formation resistivity for measured well sections; and g) determining residua

Abstract: The invention relates to a logging tool (1) for determining properties of a fluid (2) surrounding the tool arranged downhole in a casing (3) comprising a wall (4) and having a longitudinal extension. The logging tool has a substantially longitudinal cylindrical shape with a longitudinal axis and, when seen in cross-section, a periphery (5). Moreover, the logging tool comprises a plurality of electrodes (6) arranged spaced apart around the longitudinal axis in the periphery of the tool so that the fluid flows between the electrodes and the casing wall, and a measuring means for measuring the capacitance between two electrodes in all possible combinations giving n*(n?1)/2 capacitance measurements for n electrodes.

Abstract: To characterize an earth subterranean structure using a measurement assembly including electromagnetic (EM) receivers and one or more EM sources, measured voltage data collected by EM receivers in response to transmission by one or more EM sources is received. Based on a model, predicted EM data is computed. Inversion is iteratively performed according to a function that computes a difference between the measured voltage data and a product of a term containing the predicted EM data and a term containing distortion data that accounts at least for distortion effect by an environment of the measurement assembly. The inversion is iteratively performed to solve for parameters of the model and the distortion data.

Abstract: An apparatus and method for reducing a pipe residual signal from transient signals in an induction tool having a metallic pipe with finite, non-zero conductivity in a borehole penetrating an earth formation. The apparatus may include a transient electromagnetic (TEM) signal transmitter, at least one receiver configured to generate an output signal in response to the TEM signal, and at least one processor for estimating an updated model with an improved estimate of the resistivity property. The updated model may be estimated based on a difference between a simulated signal from an initial model and the output signal. The difference may be represented by a set of basis functions. The method includes using the apparatus.

Abstract: Disclosed is a method of estimating a property of an earth formation penetrated by a borehole. The method includes conveying a carrier through the borehole and performing a plurality of electrical measurements on the formation using a sensor disposed at the carrier and having a plurality of electrodes disposed in a concentric arrangement wherein a standoff distance between the sensor and a wall of the borehole has an influence on each electrical measurement in the plurality of electrical measurements. The method further includes determining an impedance for each electrical measurement in the plurality of electrical measurements and inputting the determined impedances into an artificial neural network implemented by a processor. The artificial neural network outputs the property wherein the outputted property compensates for the influence of sensor standoff distance on each electrical measurement in the plurality of electrical measurements.

Abstract: A transient electromagnetic signal is recorded in an earth formation in the presence of a pipe having a finite conductivity. A portion of the signal dominated by the pipe signal is analyzed to determine a functional representation, extrapolated back to a time interval where the formation signal is present and subtracted from the recorded signal to provide a corrected signal.

Abstract: The present disclosure provides a method and apparatus for performing resistivity measurements of a borehole wall using a transverse octupole sensor. The sensor may be a resistivity sensor. Higher resolution is obtained with an octupole sensor than with lower-order-pole sensors. For the resistivity case, the ratio of dual-frequency measurements has reduced sensitivity to standoff.

Abstract: Method and apparatus for transmitting a first data set from a tool to a receiver are provided. The method includes: obtaining a first plurality of measurements using the tool to form a first dataset; saving data from the first plurality of measurements that form the first dataset in non-volatile memory; transmitting first data-groups derived from the first dataset to the receiver, each of the first data-groups comprising different measurements of the formation; and storing in the non-volatile memory a storage position of a last transmitted first data-group. Upon restoration of a loss of communications that prevents transmission of all the first data-groups, determining the storage position of the last transmitted first data-group; and continuing the transmission of the first data-groups from the storage position of the first data-group last transmitted before the loss of communications.

Abstract: An apparatus for estimating a property of a formation penetrated by a borehole, the apparatus having: a first electrode and a second electrode configured to couple to a characteristic impedance of a material disposed in the borehole; a third electrode configured with the first electrode to electrically couple to a characteristic impedance of the formation; a circuit element coupled to the first electrode and to the second electrode and having a characteristic impedance; a first sensing circuit coupled to the circuit element and configured to provide a first signal related to the impedance of the borehole material; and a second sensing circuit coupled to the first electrode and the third electrode and configured to provide a second signal related to the characteristic impedance of the formation; wherein the first signal and the second signal are used to estimate the property. A method is also provided.

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

Abstract: A method and system for processing three component seismic data includes determining a covariance data matrix from three component seismic data for each of a plurality of time periods to obtain eigenvectors and eigenvalues. One or more seismic attributes are calculated from the eigenvectors and eigenvalues for each of a plurality of time periods. A stability measure is determined from the calculated seismic attribute for each of the plurality of time periods and stored for display.

Abstract: The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more antennas, at least one of the antennas being a non-co-located triaxial antenna, is provided. Azimuthally sensitive measurements are obtained using the antennas of the downhole logging tool. The measurements are fitted to a Fourier series having Fourier coefficients and the non-co-location of the triaxial antenna is compensated for by adjusting the Fourier coefficients. Compensated measurements are determined using the adjusted Fourier coefficients and the formation property of the subsurface formation is determined using the compensated measurements. The compensating may use one or more scale factors that depend on an amplitude, phase, and/or frequency of the received signal, and an alignment angle between the triaxial antenna and another of the antennas of the logging tool.

Abstract: A machine, method and computer-usable medium for modeling an average flow of a substance through a composite material. Such a modeling includes an analytical calculation of an effective tensor Kå suitable for use with a variety of media. The analytical calculation corresponds to an approximation to the tensor K, and follows by first computing the diagonal values, and then identifying symmetries of the heterogeneity distribution. Additional calculations include determining the center of mass of the heterogeneous cell and its angle according to a defined Cartesian system, and utilizing this angle into a rotation formula to compute the off-diagonal values and determining its sign.

Abstract: A method for determining electromagnetic induction properties of subsurface rock formations includes determining an eccentering angle of a well logging instrument disposed in a wellbore. The instrument includes at least one triaxial induction transmitter and at least one triaxial induction receiver. The eccentering angle is determined from symmetric cross component measurement differences. The triaxial induction measurements made from the at least one receiver are rotated to an apparent eccentering angle of zero. At least one electromagnetic induction property is determined from the rotated triaxial induction measurements.

Abstract: An empirical method of measuring water saturation in hydrocarbon bearing formations is described. The system described herein accurately calculates water saturation, shale volume, volume of total organic carbon, and other formation parameters under a variety of formation conditions.

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: The grain size distribution of a pore-scale geometric model of a clastic earth formation are adjusted so that the NMR relaxation time distribution output of the model matches a measured NMR distribution, and an acoustic velocity output of the model matches a measured acoustic velocity (compressional and/or shear). Fluid drainage and imbibing can be simulated. Additional properties of the earth formation are predicted using the pore-scale model. The additional properties may be based on additional measurements of properties of a fluid in the formation.

Abstract: A method for making directional resistivity measurements and forming a directional resistivity image of a subterranean formation includes processing a plurality of directional resistivity measurements and corresponding azimuth angles to calculate a first order harmonic representation at selected azimuth angles. A two dimensional borehole image may be formed by repeating the procedure at multiple measured depths in the borehole.

Abstract: A method for simulating a conductivity measured by a resistivity tool disposed in a borehole penetrating a formation, the method including: constructing a main grid extending from the borehole into the formation; constructing an auxiliary grid that is local to the main grid and fitted to a boundary between a first region having a first conductivity and a second region having a second conductivity; discretizing a problem operator on the auxiliary grid applying Maxwell's Equations to a volume represented by the auxiliary local grid, the Maxwell's Equations including a term representing the conductivity of a material in the volume; calculating one-dimensional functions for points on the auxiliary grid; constructing basic functions from the calculated functions; discretizing by the basic functions for points on the main grid; solving the resulting set of equations to obtain the simulated measured conductivity for the resistivity tool; and providing the simulated measured conductivity as output.

Abstract: A towed marine source to borehole electromagnetic survey system and method for surveying employing the same is disclosed. The system includes a sea vessel adapted for traversal of sea water over a subsea formation, a power supply affixed to the sea vessel and a high moment loop source coupled to the power supply, and a signal generator by a tow cable; said signal generator being affixed to the sea vessel configured to control operating parameters of the high moment loop source. The system also includes a wellbore drilled in the subsea formation, a series of electromagnetic (EM) receivers positioned in the wellbore. Each receiver includes a sensor module having sensing elements to measure one or more of electric fields, electric currents, and magnetic fields produced by the high moment loop source when towed by the sea vessel, and a storage device configured to store data from measurements made by the sensor module.

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 method and system for determining dynamic permeability of gas hydrate formations including deploying a tool within a wellhole configured for magnetic resonance measurements, determining permeability of a formation at or near zero saturation of the gas hydrate and deriving the relationship between permeability and gas hydrate saturation for the formation.

Abstract: Systems and methods for controlling a drill string are provided. A method comprises receiving one or more first signals from a first sensor package mounted in a first portion of the drill string at a first position within a wellbore. The first signals may be indicative of an orientation of the first portion of the drill string. The method also includes receiving one or more second signals from a second sensor package mounted in a second portion of the drill string at a second position within the wellbore. In certain embodiments, the second signals indicative of an orientation of the second portion of the drill string. The drill string may be adapted to bend between the first portion and the second portion and certain embodiments include calculating a first amount of bend between the first portion and the second portion in response to the first signals and the second signals.

Abstract: In one aspect a method of drilling a borehole is disclosed, wherein the method includes generating a primary electromagnetic field with a transmitter in a second borehole spaced from the first borehole, the primary electromagnetic filed causing electrical current in the conductive material of the first borehole, measuring a secondary electromagnetic field at a receiver in the second borehole, the electromagnetic field being responsive to the electrical current flowing in the conductive material in the first borehole, and determining a location of the first borehole using the measured secondary electromagnetic field.