Abstract: A method for estimating an impedance of a material behind a casing wall in a borehole, the method comprises exciting (602) the casing wall with an acoustic pulse, and measuring (603) an experimental acoustic waveform (W) reflected from the casing wall. The method further comprises initializing (600) an impedance parameter (Zin), computing (601) an inverse casing response (Rcas?1) as function of the impedance parameter, and deconvoluting (604) the experimental acoustic waveform with the inverse casing response to obtain a transducer (T). An iterative loop (605, 606, 607) is performed, comprising the computing of an inverse casing response and the deconvoluting of the experimental acoustic waveform by varying (607) the impedance parameter until the transducer response becomes compact (605, 606) in the time domain. The estimated impedance (Zcem) is obtained (606) from the impedance parameter when the transducer response is compact.

Abstract: To survey a subterranean structure, first measurement data according to a first electromagnetic survey technique and second measurement data according to a second, different electromagnetic survey technique are received. An output value for surveying the subterranean structure is computed based on the first and second measurement data.

Abstract: A vehicle technician time clock tool comprises a computer-implemented interface to a database, wherein the database contains vehicle service task-related information and time-related information, the vehicle service task-related information and time-related information pertaining to at least one vehicle technician, and a computer-implemented graphical user display (GUI), wherein the GUI displays in real time at least some of the vehicle service task-related information, at least some of the time-related information, and at least one calculation based on at least some of the time-related information.

Abstract: A method to determine one or more properties of a substance in a downhole region of investigation is disclosed. The method includes obtaining NMR measurements from the region of investigation, obtaining at least one additional well log measurement from the region of investigation, expressing the NMR measurements in terms of NMR subcomponents, expressing the additional well log measurement in terms of well log subcomponents, and simultaneously inverting the expressed NMR measurements and the expressed additional well log measurement for the NMR subcomponents to yield one or more properties of a substance.

Abstract: Multifrequency focusing is applied to measurements made with a multicomponent resistivity logging tool in an earth formation having resisitivity anisotropy. From knowledge of relative dip and azimuth of the borehole relative to the formation, two modes can be separated, one of which is dependent substantially on the horizontal resistivity. Alternatively, mode separation and angle determination can be made simultaneously.

Abstract: A method and apparatus are provided for detecting and transmitting geophysical data from a plurality of electrodes inserted into the soil utilizing a set of identical dynamically reconfigurable voltage control units located on each electrode and connected together by a communications and power cable. A test sequence is provided in each voltage control unit. Each voltage control unit records data measurements for transmission to a central data collector. Each voltage control unit incorporates and determines its positional relationship to other voltage control units by logging when the unit is attached to the electrode. Each voltage control unit I equipped with a magnetic switch for detecting when they are in contact with the electrode.

Abstract: A method for modeling borehole effects of a transverse array induction tool includes selecting a formation-borehole model having a set of parameters, wherein the set of parameters comprises a direction of tool eccentering; determining initial values for the set of parameters; computing expected responses for a selected set of arrays from the plurality of arrays of the induction tool, wherein the computing is based on the formation-borehole model; comparing the expected responses with actual responses for the selected set of arrays; adjusting values of the set of parameters, if a difference between the expected responses and the actual responses is no less than a predetermined criterion; repeating the computing, the comparing, and the adjusting, until the difference between the expected responses and the actual responses is less than the predetermined criterion; determining the borehole effects from final values of the set of parameters.

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: A method for correcting induction conductivity well log measurements for conductivity of a wellbore and a formation proximate the wellbore includes estimating an effective formation conductivity for the formation proximate the wellbore from measurements made by an induction receiver proximate an induction transmitter. The effective formation conductivity is used to correct apparent conductivity measurements made by at least one induction receiver on the instrument.

Abstract: The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. The parameters of interest may be transmitted to the surface at a plurality of resolutions using a multi-resolution image compression method. Parameters of interest are formed into a plurality of Cost Functions from which Regions of Interest are determined to resolve characteristics of the Features of interest within the Regions. Feature characteristics may be determined to obtain time or depth positions of bed boundaries and borehole Dip Angle relative to subsurface structures, as well borehole and subsurface structure orientation. Characteristics of the Features include time, depth, and geometries of the subsurface such as structural dip, thickness, and lithologies.

Abstract: There is provided herein a system and method of collecting, EM data in the context(s) of hydrocarbon exploration, appraisal, development, and surveillance, which provides improved ground coupling between the electrodes and the earth or surface ice and, as a consequence, a higher quality transmitted and received signal is obtained thereby. Where the surface of the ground is saturated and frozen (e.g., in the case of a survey conducted on sea ice or frozen tundra), the survey instruments (sources and receivers) may be coupled more faithfully to the surface by drilling or melting holes into the ice (or frozen tundra) and inserting electrodes into the resulting holes. Each hole may (or may not) be lined with material to retard the loss of water therefrom. Preferably, each of the holes (source and receiver) will be filled with water (fresh or salt) before data collection begins.

Abstract: Techniques for estimating the fraction of water in formations being investigated use measurements of dielectric permittivity at a number of frequencies. The techniques have the advantage of minimizing or eliminating external inputs that can introduce inaccuracies.

Abstract: A computer-based method is provided for modeling and visualizing a property of a subterranean earth formation while drilling a borehole therethrough. The computer-based method gathers electromagnetic signals corresponding to a current measurement station location of a measurement-while-drilling tool, and generates a multilayer model corresponding to such electromagnetic signals. A histogram characterizing uncertainty of the multilayer model is used to generate a set of color hue values which represent predictions of the formation property for depth values above/below the tool, and a corresponding set of saturation values (which represent uncertainties for these predictions). A curtain plot is generated and displayed. The curtain plot employs colors to visualize formation property predictions for depth values above/below the tool over successive measurement station locations. A new column of the curtain plot is generated for the current measurement station location.

Abstract: Techniques for determining formation characteristics use measurements of dielectric permittivity at a number of frequencies. Determined characteristics include the vertical and horizontal formation dielectric constant and conductivity, the formation water conductivity, the water saturation, the cementation and the saturation exponents. In laminated formations these profiles can be determined for each lamina. Also, formation dielectric properties are used in determination of the rock type.

Abstract: A technique of estimating electrical parameters of an earth formation accounts for spatial inhomogeneities and frequency dispersion. The results are achieved using a model which is evaluated to generate predicted values for a plurality of electrical signals measured in a borehole in an earth formation as a function of a first set of model electrical parameters, a second set of model electrical parameters and model spatial coordinates of boundaries between regions of the earth formation. Transformations are applied to the measured electrical signals and the predicted values. The electrical parameters and spatial coordinates are selected to cause approximate agreement between the transformed measurements and the transformed predicted values.

Abstract: The grain size 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. 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: Methods and systems are provided for displaying and forecasting the lithology and wellbore conditions to be encountered while conducting drill string operations in a wellbore. A method and system is described for predicting and modeling lithology while operating a drill string in a wellbore, comprising: developing a 3-D lithological model of a subsurface area; projecting a well path through said subsurface area; determining an open cylinder lithology display of said projected well path; and recording said determined open cylinder display. The open cylinder lithology display (the Predictive Stratigraphy Image) may be displayed with geological or structural cross-sections to compare the well path and the predicted well path, with the actual subsurface environment. Data acquired during drilling operations can be used in real time to update the model or the Predictive Stratigraphy Image, and the results compared with Predictive Image Logs and other wellbore images and data.

Abstract: Measurements made by multiarray and multicomponent induction resistivity measurements in a borehole are used for determining the orientation and length of fractures in an earth formation when the fractures have a fluid with a resistivity different from that of the earth formation. The apparatus and method may also be used in anisotropic earth formations where the vertical and horizontal resistivities are different.

Abstract: A method for interpreting transient electromagnetic survey data includes measuring transient response of a medium over a plurality of switching events. The measured transient response to a first one of the current switching events is modeled. Transient response to the model for at least one current switching event prior in time to the at least a first current switching event is calculated. The calculated transient response is summed with the first event measured response and the sum is compared to the electromagnetic survey measurements. The model is adjusted and the calculating summed transient responses is repeated until a difference between the summed calculated responses and the survey measurements falls below a selected threshold.

Abstract: Multi-component induction measurements are made using a resistivity logging tool in an anistropic earth formation. A subset of the multi-component measurements are inverted to first determine horizontal resistivities. Using the determined horizontal resistivities and another subset of the multi-component measurements, the vertical resistivities are obtained. Results of using the in-phase signals are comparable to those obtained using multifrequency focusing of quadrature signals.

Abstract: Measurements are made with a multicomponent logging tool in an earth formation. The measurements are inverted without using a selected cross-component measurement. The model is then used to predict the value of the selected cross-component. A misalignment angle of the tool is estimated from the predicted and actual values of the selected cross-component.

Abstract: Method for removing effects of shallow resistivity structures in electromagnetic survey data to produce a low frequency resistivity anomaly map, or alternatively imaging resistivity structures at their correct depth levels. The method involves solving Maxwell's electromagnetic field equations by either forward modeling or inversion, and requires at least two survey data sets, one taken at the source frequency selected to penetrate to a target depth, the other a higher frequency able to penetrate only shallow depths.

Abstract: Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole. 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. 37 CFR 1.72(b).

Abstract: Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole. 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: 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: Mineral exploration needs a reliable method to distinguish between uneconomic mineral deposits and economic mineralization. A method and system includes a geophysical technique for subsurface material characterization, mineral exploration and mineral discrimination. The technique introduced in this invention detects induced polarization effects in electromagnetic data and uses remote geophysical observations to determine the parameters of an effective conductivity relaxation model using a composite analytical multi-phase model of the rock formations. The conductivity relaxation model and analytical model can be used to determine parameters related by analytical expressions to the physical characteristics of the microstructure of the rocks and minerals.

Abstract: Multicomponent measurements made in a cross-bedded earth formation are processed to give one or more equivalent TI models. Resistivity information about the cross-bedding is obtained from one of the TI models and a measured cross-bedding angle. Resistivity information about the cross-bedding may also be obtained using a combination of two or more of the equivalent TI models.

Abstract: A method and apparatus for real-time well-site interpretation of array resistivity log data. An inversion of data with different depths of investigation is carried out after data shoulder-bed correction. The formation model used by inversion is constructed with the layer boundaries obtained from an imaging tool or other log measurements.

Abstract: Roughly described, a method for numerically solving a system of equations of the form 0=F(X), for a solution vector X which involves choosing a starting value X0 and iterating Xn+1=Xn?[F?(Xn)+?nDiag F?(Xn)]?1F(Xn). In this iteration, at least one ?n is a number greater than 0. Preferably, ?n=min {?/n, [?n/(1+n?n)]?F(Xn)?}, where ? is a constant that remains fixed for all n, and ?n=?F(Xn)?/?F(Xn?1)?.

Abstract: An induction logging tool having transmitter and receiver antennas is used to make measurements of earth formations. The antennas may be mounted on the mandrel of a bottomhole assembly for MWD applications, or may be pad mounted for wireline applications. The induction measurements are inverted using a linearized model. The model parameters are determined in part from caliper measurements.

Abstract: A method to estimate water saturation (Sw) of a thin-bedded formation is provided including (a) developing a model of anisotropy of resistivity (Rv/Rh) a function of water saturation (Swt) for one or more volume fractions (either Fshale or Fsand); (b) measuring the anisotropy of resistivity of the formation; (c) measuring the volume fraction of the formation; (d) correlating anisotropy of resistivity to the measured volume fraction of the formation using the model to estimate the water saturation (total water saturation or sand water saturation) of the formation.

Abstract: The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in a borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. As necessary, azimuths associated with the measurements are obtained and corrections applied. The corrected data may be filtered and/or smoothed. The parameters of interest associated with azimuthal sectors are depth matched, resolution matched and filtered, and the acquisition effects removed. The data are denoised using a multi-resolution wavelet transform. The data acquired with separate transducers are resolution matched to obtain a resolution matched data series. Subsequently the resolution matched data may be further denoised using a multi-resolution wavelet transform.

Abstract: Methods and systems for extracting formation properties from formation logging data is disclosed. A method includes obtaining a deconvolution filter; and processing the formation logging data using the deconvolution filter to produce estimates of the formation properties. The estimates of the formation properties may be further processed with a diffusion filter, which may be an anisotropic diffusion filter. A system for extracting formation properties from formation logging data includes a central processing unit and a memory, wherein the memory stores a program having instructions for performing a method that includes designing a deconvolution filter; and processing the formation logging data using the deconvolution filter to produce estimates of the formation properties.

Abstract: A method and a computer program product for estimating the true intrinsic relaxation time T2 and the internal gradient Gint for a multi-frequency nuclear magnetic resonance imaging tool for well logging includes providing at least two frequencies in a plurality of echo trains, evaluating the signal decay in each echo train, quantifying the signal decay and correlating the signal decay to the internal gradient.

Abstract: A technique is described for interpretation of IPTT tests. In one implementation, the technique may be configured or designed to standardize the complete interpretation procedure of IPTT in a heterogeneous reservoir, using if available, modern wireline logs (such as, for example, nuclear magnetic resonance and imaging), dynamic data from wireline formation testers and/or any other relevant information (such as, for example, geological description, core data and local knowledge) as constraints on the interpretation. Additionally, an iterative method may be used to define formation layering. An advanced regression technology may also be used to obtain optimized horizontal and vertical permeabilities of reservoir layers.

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 anisotropic medium are determined. The results are used for reservoir navigation in anisotropic media.

Abstract: A method for determining spatial distribution of resistivity of Earth formations surrounding a wellbore having a conductive pipe therein includes measuring resistivity of the Earth formations using measurements of current leakage along the pipe at selected axial positions. Electromagnetic properties of the Earth formations are measured from within the pipe. The measurements of electromagnetic properties correspond to a larger axial distance and to a greater lateral distance than the measurements of resistivity from current leakage. The current leakage and electromagnetic measurements are jointly inverted to obtain a model of the spatial distribution.

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 anisotropic medium are determined. The results are used for reservoir navigation in anisotropic media.

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 to determine water saturation of laminated sand-shale formations based on measurements of formation and shale resistivity anisotropy, the fraction of shale, and the porosity.

Abstract: The invention concerns a method for determining the resistivity in a formation crossed by a cased well, in which one carries out at least one resistivity log in the cased well and one uses the results of at least one resistivity log in the non-cased well, carried out in the same well previously, in order to, in at least one zone (10) of the formation in which the resistivity has not changed between the cased and non-cased condition, deduce the value of a geometric factor k conditioning the resistivity and for determining, by means of said geometric factor k and the log in the cased well, the resistivity in at least one zone (11) different to the calibration zone, in which the resistivity has varied between the non-cased condition and the cased condition.

Abstract: A monitoring system for use with a horizontal directional drilling machine and adapted to determine the roll and/or pitch orientation of the downhole tool assembly by detecting signals from a sensor assembly supported by the downhole tool assembly. In a preferred embodiment, the monitoring system uses an antenna assembly to detect a signal transmitted from the sensor assembly. The antenna assembly transmits the detected signal to a processor which determines a calibration factor indicative of the actual orientation of the sensor relative to the known orientation of the downhole tool assembly. The processor then uses the calibration factor and the signal emitted from the sensor, indicative of the actual orientation of the sensor, to determine the actual orientation of the downhole tool assembly.

Abstract: A system and method estimates the distance between a borehole and a subsurface boundary of interest in a geophysical region. In one embodiment, available existing sensor data for the geophysical region is used to create a resistivity model of the region, with the model reflecting changes in resistivity across the boundary. A hypothetical borehole has a number of segments along its length that are spaced-apart from the boundary by different, preselected distances. The ratio between two selected resistivity curves in each of the respective spaced-apart segments is computed, and these ratio values are plotted as a function of distance from the boundary. A curve-fitting algorithm is applied to derive an equation, which may be applied to actual sensor data from a sensor package.

Abstract: Briefly, a method of estimating electrical parameters of an earth formation employs a simplified model of a measurement tool or device in transforming or normalizing data measured by the measurement tool. Electrical parameters of the earth formation, such as conductivity or dielectric constant, for example, may be estimated based on the normalized data.

Abstract: Apparatus for conducting geophysical surveys comprising a multiplicity of intelligent electrodes provided on a multi-conductor cable, for receiving a command signal in response to which predetermined electrodes are connected to selected conductors in the cable. Each intelligent electrode is identical in all respects, including its programming, resulting in simplified construction of the cable and easy replacement of the intelligent electrodes. Instead of assigning a unique address code to each switch in a series of take-outs on a multi-conductor cable, each electronic switch is programmed with the same address code. That is, each switch is programmed to be activated when it receives a code command that, for example, is prefaced with a particular address, e.g. the number 1. The second part of the code (y) instructs the switch as to which conductor in the multi-conductor cable is to be connected to the local electrode at the location of the switch.

Abstract: A method of determining the distribution of shales, sands and water in a reservoir including laminated shaly sands using vertical and horizontal conductivities derived from nuclear, NMR, and multi-component induction data such as from a Multicomponent Induction Logging Tool

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 of characterizing a borehole traversing an earth formation including (a) obtaining an array of data from a formation characterization tool, wherein the data describes a section of the borehole; (b) computing at least one spatial characteristic describing the relative position of pairs of data; (c) assigning said pairs of data to bins based on the spatial characteristic, wherein the size of the bins are selected based on the tool; (d) transforming the data to petrophysical properties of the borehole; (e) calculating the variance of each bin; (f) developing a model of the variances; (g) determining at least one geostatistical parameter using the model; and (h) upscaling the geostatistical parameters to characterize a region of said earth formation. The method may further include generating a heterogeneity index log using the geostatistical model parameters. The method may be implemented using a computer program product for processing and interpreting borehole data.

Abstract: Methods for evaluating the properties of formations surrounding a borehole, include the steps of measuring electrical properties of the formation from within the borehole; deriving a model of parameters of the formation surrounding the borehole; and estimating the properties of the formation using the model to interpret the measured electrical properties. In one aspect of the invention in which the formation includes a series of distributed beds, each bed having specific properties. Another aspect includes grouping similar beds, assigning one or more properties to all of the beds in a group, and using the assigned properties to estimate the properties of the formation for measurements relating to the beds of that group. Another aspect includes making several different measurements of formation electrical properties and simultaneously estimating the formation properties from the different measurements to provide a joint inversion.

Abstract: A method provides early estimation of product life using accelerated stress testing data. In an embodiment, data measured from a product operating in a first, high-stress environment is used to predict how long the product will operate in a second, normal operating environment before failure, using an exponential acceleration model. An additional feature of the present invention provides a quantified indication of how much the product has improved from a redesign.