Abstract: Systems, methods, and instructions encoded in a computer-readable medium can perform operations related to simulating subterranean fracture propagation. A subterranean formation model representing rock blocks of a subterranean formation is received. The subterranean formation model is used to predict a response of each rock block to one or more forces acting on the rock block during an injection treatment for the subterranean formation. The predicted responses of the rock blocks may include, for example, a fracture, a rotation, a displacement, a dilation of an existing fracture, and/or another type of response. In some implementations, an injection treatment may be designed for a subterranean formation based on the predicted response of the rock blocks.

Abstract: Method for speeding up iterative inversion of seismic data (106) to obtain a subsurface model (102), using local cost function optimization. The frequency spectrum of the updated model at each iteration is controlled to match a known or estimated frequency spectrum for the subsurface region, preferably the average amplitude spectrum of the subsurface P-impedance. The controlling is done either by applying a spectral-shaping filter to the source wavelet (303) and to the data (302) or by applying the filter, which may vary with time, to the gradient of the cost function (403). The source wavelet's amplitude spectrum (before filtering) should satisfy D(f)=fIp(f)W(f), where f is frequency, D(f) is the average amplitude spectrum of the seismic data, and Ip(f) is the average amplitude spectrum for P-impedance in the subsurface region (306,402) or an approximation thereof.

Abstract: A method for determining the frequency-dependent dielectric permittivity spectrum of a rock sample, comprising:—defining a series of electromagnetic measurement data comprising at least a first measurement at a frequency from which a substantially frequency-independent value of dielectric permittivity ??, can be obtained; and at least second and third measurements at different frequencies from which values for frequency-dependent dielectric permittivity ?rock (f) can be obtained; and—using the first, second and third measurements to determine the frequency-dependent spectrum of the sample.

Abstract: Systems, methods, and instructions encoded in a computer-readable medium can perform operations related to simulating injection treatments applied to a subterranean formation from multiple well bores in the subterranean formation. A subterranean formation model representing rock blocks of a subterranean formation is received. Information on multiple injection treatments for multiple well bores in the subterranean formation is received. The subterranean formation model and the information on the injection treatments is used to predict a response of each of the rock blocks to forces acting on the rock block during the injection treatments. The injection treatments may include, for example, multiple fracture treatments for simultaneous application to the subterranean formation. In some implementations, injection treatments may be designed for a multiple-well bore system based on the predicted response of the rock blocks.

Abstract: A computer-implemented method includes obtaining road sensor data reflecting speeds of traffic on road segments, transforming the road sensor data using vehicle probe data for the road segments reflecting vehicle speeds, and producing speed estimates for the road segments using the transformed road sensor data. The method can further include determining speeds for road segments between road sensors by smoothing data from sensors near the road segments.

Abstract: Methods, systems, and apparatus for inducing fractures in a subterranean formation and more particularly methods and apparatus to place a first fracture with a first orientation in a formation followed by a second fracture with a second angular orientation in the formation are disclosed. The first and second fractures are initiated at about a fracturing location. The initiation of the first fracture is characterized by a first orientation line. The first fracture temporarily alters a stress field in the subterranean formation. The initiation of the second fracture is characterized by a second orientation line. The first orientation line and the second orientation line have an angular disposition to each other.

Abstract: A method for monitoring oil based mud filtrate contamination is provided including steps of analytically dividing a fluid stream into two parts, determining a gas/oil ratio for a native fluid determining an apparent gas/oil ratio for the contaminated fluid and determining on a volume fraction, an oil based contamination level based upon the gas/oil ratio for the native fluid and the apparent gas/oil ratio for the contaminated fluid.

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

Abstract: A well advisor system and console for monitoring and managing cementing operations in a well. The system may be accessed through one or more workstations, or other computing devices, which may be located at a well site or remotely. The system is in communication with and receives input from various sensors. It collects real-time sensor data sampled during operations at the well site. The system processes the data, and provides nearly instantaneous numerical and visual feedback through a variety of graphical user interfaces (“GUIs”), which are presented in the form of an operation-specific console.

Abstract: This specification describes systems, methods, and software relating to geomechanical modeling of a subterranean region (104). In some aspects, finite difference (FD) grid data (200a) and finite element (FE) mesh data (202a) are received. The FD grid data include FD grid node locations (210) and FD grid values. The FD grid values include values of a subterranean formation property for each FD grid node location. The FE mesh data include FE mesh node locations (212) and spatial domains (214) for each of the FE mesh node locations. Values of the subterranean formation property are generated for each of the FE mesh node locations. The value for a given FE mesh node location is generated based on the FD grid values for FD grid node locations within the spatial domain about the given FE mesh node location. The generated values are assigned to the FE mesh node locations of the FE mesh data (202b) for geomechanical modeling of the subterranean region.

Abstract: A well advisor system and console for monitoring and managing installation of casing and tubular goods in a well. The system may be accessed through one or more workstations, or other computing devices, which may be located at a well site or remotely. The system is in communication with and receives input from various sensors. It collects real-time sensor data sampled during operations at the well site. The system processes the data, and provides nearly instantaneous numerical and visual feedback through a variety of graphical user interfaces (“GUIs”), which are presented in the form of an operation-specific console.

Abstract: Methods, apparatuses and computer readable instructions for determining the effectiveness of, and for performing, a low salinity waterflood. An ion diffusion distance value is determined based on the rate of diffusion of ions within the rock of a reservoir and the residency time of floodwater within the reservoir. The thickness of the layers of the reservoir are compared to this ion diffusion value to determine the effectiveness of performing a low salinity waterflood and also to enable the effective control of a waterflood and to assist in the determination of locations of wells.

Abstract: Data transmission from a bottom hole assembly (BHA) includes obtaining a scan from multiple scans forming a downhole data log of a borehole within a subterranean formation. The scan includes a sequence of data items from a sensor in the BHA located in the borehole. Each data item corresponds to an azimuth angle of the sensor. Further, compressed scan data is generated from the sequence of data items on a per-scan basis, and transmitted, using a pre-determined borehole telemetry, to a surface unit.

Abstract: Testing water contamination around oil or gas wells. To determine a testing zone around an oil or gas well, multiple variables are received by data processing apparatus. The variables include variables associated with an oil or gas well, variables associated with an entity performing hydraulic fracturing in the oil or gas well, and variables associated with inhabitable regions surrounding the oil or gas well, to name a few. The multiple variables are processed by the data processing apparatus. In response to the processing, a zone around the oil or gas well within which to test for contamination due to the hydraulic fracturing in the oil or gas well is determined.

Abstract: A method, apparatus, and program product utilize global sensitivity analysis (GSA) based on variance decomposition to calculate and apportion the contributions to a total variance of a measurement signal from uncertain input parameters of a subsurface model in connection with designing targeted surveys. Through the use of global sensitivity analysis in this manner, the geometry for a survey may be determined based on a desired target of the design, e.g., based on spatial properties (e.g., reservoir zone of interest) and/or physical properties (e.g., porosity, fluid density, rock physics properties) to select locations (e.g., source-receiver pairs) with greater uncertainty contributions from parameter group(s) of interest.

Abstract: A method is disclosed of enhancing one or more attributes of a log, of a geological formation, including data generated in plural measurement channels corresponding to plural measurement devices, the method including the steps of: selecting data corresponding to a single said channel and deconvolving it; and seeking to impose one or more attributes of the resulting deconvolved data onto convolved log data of plural said channels in order to create an enhanced log.

Abstract: A system for creating a log during gas detection and monitoring is disclosed herein. The system can include a gas detection and well logging device for sensing and transmitting data, which can include a processor in communication with a monitoring device. The monitoring device can monitor, acquire, and transmit data associated with a drilling operation. The processor can receive the data, calibrate the data, and log the data into files. The processor can capture sensed data based on a time event and a depth event. The processor can scale the data and form a geological-hydrocarbon log for transmission. A client device can be in communication with the gas detection and well logging device, and can have computer instructions for querying the geological hydrocarbon log, the data, and the files to obtain real time streaming data for instant display.

Abstract: NMR measurements are made along with acoustic measurements using one tool. The antenna of the NMR sensor is used to create acoustic signals. Interference between the acoustic and NMR measurements is avoided due to the frequency difference, and by having the acoustic excitation during a wait time of the NMR pulse sequence.

Abstract: A networked information management system and architecture for managing files and documents pertaining to oil and gas wells and properties. On request by an authenticated user, a client workstation displays geographical information system (GIS) layers, via a web collaboration portal, for a region of the earth at which wells or properties may be located. The wells or properties within the displayed region enable links to documents or files associated with those wells and properties, and by way of which the system user can access the documents and files. Both structured and unstructured data elements can be accessed by the system. A collaboration portal allows for standardized access to the data, and also for simultaneous or collaborative access to the data. Workflow management capability is also implemented.

Abstract: A system for determining the amount of life consumed for a tool includes at least one sensor associated with the tool for generating observation data, a memory in operable communication with the at least one sensor, the memory including a database for storing the observation data generated by the sensor, and a processor in operable communication with the memory. The processor includes a model generator that generates a current model for a current run of the tool. The current model includes parameters of a functional approximation of the observation data. The processor also includes a classifier that classifies the current model and a current run estimator that determine the amount of life consumed based on the classification of the current model and a time of use associated with the current run.

Abstract: A system, method and computer-readable medium for a drilling a borehole is disclosed. Errors associated with multi-station survey measurements are obtained and partitioned into a set of estimated errors and a set of considered errors. A post-fit covariance matrix is determined from the estimated errors and includes the effects of the considered errors on the estimated errors. A drilling parameter of a drill string in the borehole may be altered using the determined post-fit covariance matrix.

Abstract: A method of monitoring downhole assets includes tracking a location of a downhole asset relative to a first environment. The configuration information for the downhole asset is acquired, where the configuration information comprises a measurement of one or more forces applied to the downhole asset during assembly of the downhole asset in the first environment. A service life of the downhole asset is determined from the configuration information. One or more parameters related to usage of the downhole environment in a second environment are measured. A remainder of the service life of the downhole asset is determined by reducing the service life by an amount proportional to usage of the downhole asset as indicated by the measurement related to usage of the downhole asset. The remaining service life may be used to automatically initiate an order for new parts. A system of monitoring downhole assets is also disclosed.

Abstract: A method of transmitting borehole image data from a borehole location to a remote location includes obtaining a set of image data describing formation surrounding a borehole using a logging tool at a selected depth or range of depths in the borehole, extracting one or more image features from the set of image data downhole, and transmitting a representation of the extracted image features to the surface.

Abstract: Apparatus and method of conducting a drilling operation are provided. One embodiment of the method includes drilling a borehole, predicting a value of a first parameter relating to the drilling of the borehole using a geomechanical model, estimating a value of a second parameter from measurements taken by a sensor, updating the geomechanical model based at least in part on the estimated value of the second parameter, predicting a second value of the first parameter using the updated geomechanical model, and altering a drilling parameter for drilling the borehole based on the predicted second value of the first parameter.

Abstract: A method and apparatus is provided for collecting reservoir data. The method includes providing one or more electromagnetic sources for generating an electromagnetic field in a reservoir and providing one or more electromagnetic sensors equipped with capacitive electrodes. The electromagnetic source is located separately from the electromagnetic sensor. The electromagnetic sensor may either be located within a well or at the surface, is capable of measuring the electromagnetic field in three dimensions, and may be isolated from the well fluids. The data collected by the electromagnetic sensors can be used to create a model of the oil reservoir, including the water saturation.

Abstract: A recoverable data acquisition system includes at least one sensor positionable within a tubular of a completion system that is recoverable therefrom

Abstract: A wellsite system that includes a bulk material transporter, a mobile tagger, and an uplink. The bulk material transporter includes a supply of a bulk material, a meter to measure output from the supply, and a data logger to log the output as a function of a predetermined parameter. The mobile tagger assigns transfer parameters to each transfer of the bulk material from the supply to one of multiple assets located at the wellsite, including the output measured by the meter. The uplink wirelessly transmits data from the log and the transfer parameters to remote data storage not located at the wellsite.

Abstract: A method for optimizing drilling fluids by creating a proper particle size analysis and distribution curve of particle sizing within drilling fluid. The particle size distribution curve is maintained with a maximum particle sizing of 6 microns so as to not allow for coarser drilled solids to degrade beyond the point of mechanical separation to prevent a build-up of low gravity solids that can no longer be removed from the drilling fluid during the drilling operation due to their size. An optimal drilling system requires that drilling fluids be modified through the following process to attain the appropriate particle sizing distribution to: make the most efficient use of the drilling operation, reduce the amount to drilling fluids utilized, and reduce formation damage. The method generates corrective actions to modify the drilling fluids or adjust solids control equipment parameters, to obtain a unique particle size distribution throughout the drilling process.

Abstract: A sensor assembly includes an optical computing device having an integrated computational element (ICE) configured to optically interact with a fluid stream and detect a first characteristic of a substance within the fluid stream. The optical computing device is configured to generate a first signal corresponding to the first characteristic. The sensor assembly also includes a parameter sensor configured to measure a second characteristic of the fluid stream and generate a second signal corresponding to the second characteristic and a processor communicatively coupled to the optical computing device and the parameter sensor. The processor is configured to receive the first and second signals and determine a mass flow rate of the substance.

Abstract: Computer-implemented systems and methods are provided for generating corrected performance data of water flooding of an oil reservoir system based on application of a statistical correction factor methodology (SCF). For example, data related to properties of the oil reservoir system and data related to a water flooding scenario are received. Water flooding performance data is generated based on application of an analytical water flooding performance computation methodology. Based on application of the SCF methodology to the generated water flooding performance data, corrected water flooding performance data is determined, representative of oil recovery by the water flooding of the oil reservoir system. The SCF methodology can also be used to evaluate water production based on parameters such as water-oil ratio and water cut, identify possible analog reservoirs that have similar water production performance, and calculate a Gross Injection Factor to account for water loss in the reservoir.

Abstract: In an embodiment, creation of a continuous three dimensional array of data from digital information obtained from a wellbore, and representation in a seismic data formatted dataset. In an embodiment, providing the capability to export stratigraphic interpretations made while working within the 3D-log data volume back to any wellbore that is encompassed within the areal extent of the 3D-log data volume. In one embodiment, a 2D well grid creation process comprises the steps of (a) selecting an initial grid spacing, (b) assigning wells from a dataset of well data to closest nodes in the grid, (c) if a plurality of wells are assigned to a single node after completing step (b), narrowing the grid spacing and repeating step (b) until no more than one well is assigned to any node. In an embodiment the non-well nodes are populated by extrapolating from adjacent single well nodes.

Abstract: A method, apparatus and program product utilize infeasible regions projected onto sets of substantially parallel feasibility planes extending through a subsurface region to perform anti-collision and other types of hazard avoidance analysis. Hazards, e.g., existing well trajectories, that intersect the feasibility planes, as well as any uncertainties associated therewith, may be represented as infeasible regions in the feasibility planes, such that an analysis of the feasibility of a proposed well trajectory may be determined in a computationally efficient manner through a comparison of the locations, within one or more feasibility planes, of the proposed well trajectory and any infeasible regions defined in such feasibility planes.

Abstract: A load measuring system comprising a collar mounted between the two cables of the bridle on a sucker rod pump and a measuring device to determine the clamping force of the collar. When the cables are clamped together a pre-determined distance at an angle from the vertical, the load on the cables can be determined from the clamping force. The clamping force is measured by a strain gauge or other type of load cell. The load is measured and recorded at frequent intervals during the pump stroke, and by further analysis, critical operational parameters of the pump can be determined, and the information can be used to control the operation of the pump.

Abstract: Borehole image data is compressed and transmitted to the surface one or more pixilated traces at a time. The compression methodology typically includes transform, quantization, and entropy encoding steps. The invention advantageously provides an efficient fixed point Karhünen-Loève like transform for compressing sensor data. A significant reduction in latency is achieved as compared to the prior art.

Abstract: Disclosed is a method for estimating a geometry of a borehole penetrating the earth. The method includes: performing a plurality of borehole caliper measurements with N transducers at a plurality of times, wherein for each time a measurement set comprises measurements made by the N transducers at that time; dividing a cross-section of the borehole into S sectors; obtaining an estimate of the borehole geometry by connecting representative radius points in adjacent sectors; displacing each measurement set according to a displacement vector related to an offset of each measurement set from the estimated geometry if the displacement vector exceeds a selection criterion; iterating the obtaining an estimate of the borehole geometry and the displacing each measurement set based on a latest displacement vector; and providing a latest obtained estimate as the geometry of the borehole when all of the displacement vectors no longer exceed the selection criterion for the displacing.

Abstract: A computerized monitoring system and corresponding method of monitoring the status and health of a blowout preventer. The system includes a graphics display at which a graphical user interface (GUI) displays the health of various sealing elements and control systems by way of “traffic light” indicators. The health indicators are evaluated, by the monitoring system, based on a risk profile for each of the indicated elements and control systems. The risk profiles are evaluated based on inputs such as measurement inputs, feedback signals, mechanical positions, diagnostic results, drilling conditions, and other status information of the blowout preventer at a given time and based on levels of redundancy and levels of deviation from normal conditions. The GUI includes recent history of changes in operating condition, and alarm indications such as poor health, along with the times of those events.

Abstract: The method uses a gas processor, various data collection devices each having a unique device protocol to receive drilling data, calibrate the devices and graphically present the data using both time events and depth events. The method includes computer implemented steps to scale the data and form the geological-hydrocarbon executive dashboard for transmission to various client devices to obtain real time streaming data, real time calibration information, while adding and removing detection devices and sensors online without shutting down the entire monitoring and analysis system for instant display.

Abstract: Method for simultaneous full-wavefield inversion of gathers of source (or receiver) encoded geophysical data to determine a physical properties model (118) for a subsurface region, especially suitable for surveys where fixed receiver geometry conditions were not satisfied in the data acquisition. Simultaneous source separation (104) is performed to lessen any effect of the measured geophysical data's not satisfying the fixed-receiver assumption. A data processing step (106) coming after the simultaneous source separation acts to conform model-simulated data (105) to the measured geophysical data (108) for source and receiver combinations that are missing in the measured geophysical data.

Abstract: The system includes a gas processor with gas processor data storage and computer instructions to receive in various device protocols simultaneously information from rig based sensors and gas analysis devices drilling data, calibrate the devices and graphically present the data using both time events and depth events. Computer instructions scale the data and form the geological-hydrocarbon executive dashboard for transmission to various client devices to present real time streaming data, real time calibration information, real time alarms while enabling users to add and remove detection devices and sensors, including rig servers and remote servers, online without shutting down the entire monitoring and analysis system.

Abstract: Various embodiments include apparatus and methods to detect and locate conductive structures below the earth's surface. Tools can be configured with receiving sensors arranged to receive signals generated from a conductive structure in response to a current flowing on the conductive structure. Magnetic-related values from the signals can be processed, relative to the tool, to determine a position of a conductive structure from which the signal was generated in response to current flowing on the conductive structure. Additional apparatus, systems, and methods are disclosed.

Abstract: Estimating formation parameters. At least some of the illustrative embodiments are methods including: combining a first plurality of actual logs from a first plurality of actual boreholes, at least one actual log associated with each actual borehole, and thereby creating a first equivalent log along a first equivalent path; combining a second plurality of actual logs from a second plurality of actual boreholes, at least one actual log of the second plurality of actual logs associated with each actual borehole of the second plurality of actual boreholes, and thereby creating a second equivalent log along a second equivalent path; and estimating a plurality of values of a parameter of one or more formations along a proposed borehole path, each value associated with a distinct depth along the proposed borehole path, the estimating using the equivalent logs.

Abstract: A processor accepts sensor data about a geological formation from a sensor. The sensor data is such that processing the sensor data using a processing technique to estimate a parameter of the geological formation without a constraint, whose value is not yet known, produces a plurality of non-unique estimates of the parameter. The processor accepts more than two time-displaced images of fluid sampled from the geological formation. The time displacements between the images are substantially defined by a mathematical series. The processor processes the images to determine the constraint. The processor processes the sensor data using the processing technique constrained by the constraint to estimate the parameter of the geological formation. The processor uses the estimated parameter to affect the drilling of a well through the geological formation.

Abstract: A disclosed system includes a plurality of ion selective fiber sensors configured to measure treatment concentration variance, and a computer in communication with the plurality of ion selective fiber sensors. The computer determines treatment coverage for different downhole zones using information received from the plurality of ion selective fiber sensors. A disclosed method includes collecting data from a plurality of ion selective fiber sensors configured to measure treatment concentration variance. The method also includes determining treatment coverage for different downhole zones using information received from the plurality of ion selective fiber sensors. A disclosed downhole treatment management system includes a data analysis unit that collects data from a plurality of downhole ion selective fiber sensors configured to measure treatment concentration variance, and that determines treatment coverage for different downhole zones using the collected data.

Abstract: A method for controlling operations during construction of a subsurface wellbore includes measuring a plurality of wellbore construction parameters. At least one wellbore state parameter is calculated from the wellbore construction parameters in a computer. A plurality of users to communicate with the computer to enable access at least one of the measured wellbore construction parameters and the at least one wellbore state parameter. Depending on a assigned tasks, such user may receive task specific wellbore construction parameters and selected wellbore state parameters for display when a requested is communicated to the computer.

Abstract: A method of performing wellbore operations includes calculating, based on measurements obtained by drilling a wellbore, at least one wellbore quality factor of a wellbore quality index; and performing at least one wellbore operation in a wellbore through a subterranean formation, based on the at least one calculated wellbore quality factor.

Abstract: An arrangement and an associated method are described in which a boring tool is moved through the ground within a given region along a path in which region a cable is buried. The boring tool and the cable transmit a boring tool locating signal and a cable locating signal, respectively. Intensities of the boring tool locating signal and the cable locating signal are measured along with a pitch orientation of the boring tool. Using the measured intensities and established pitch orientation, a positional relationship is determined to relative scale including at least the boring tool and the cable in the region. The positional relationship is displayed to scale in one view. The positional relationship may be determined and displayed including the forward locate point in scaled relation to the boring tool and the cable. Cable depth determination techniques are described including a two-point ground depth determination method.

Abstract: Prospect assessment and play chance mapping tools are provided. For assessing potential resources, example systems provide dynamically linked chance maps, transformed in real time from geological properties. Input geological maps or other data are dynamically linked to resulting chance maps, so that changes in the input maps automatically update the chance map in real time. Users can generate a custom risk matrix dynamically linking geological maps with chance maps via interface tools, dropping maps directly into the matrix. A transform may programmatically convert the geologic domain to the chance domain. The user can navigate input maps, select areas of interest, and drag-and-drop geologic properties into an uncertainty engine and distribution builder for uncertainty assessment based on geologic reality. A merge tool can programmatically unify multiple geological interpretations of a prospect. The merge tool outputs a single chance of success value for multiple geologic property values at each grid node.

Abstract: A method for allocating actual production loss of a wellsite. The method includes defining a data collection procedure and capturing production data according to the data collection procedure, the production data including actual production data and a maximum production potential of the wellsite. The method further includes selectively allocating a portion of the actual production data to the wellsite based on allocation rules to obtain derived production data, comparing the derived production data to the maximum production potential to determine the actual production loss for the wellsite, allocating the actual production loss to at least one of the production events, and determining a cause of the actual production loss based on an engineering analysis of the production events.

Abstract: A system for building a geological model of oil or other mineral deposit. In particular, the system allows the coefficients of correlation to be determined for a set of well-logging curves and marker depth positions to be established for which the values of correlation coefficient are maximal. A technical result is the improvement of the accuracy of evaluating the parameters that are used to construct a geological model of location of oil or other deposits. The system makes it possible, given a marker, which already has its marks in a group of wells, which is referred to as reference group, to calculate such marks for wells from another group. For any well W where the marker depth is to be determined, wells from the reference group are chosen lying within the specified distance from the well W, and a well with the maximal coefficient of correlation is chosen among them.

Abstract: The invention relates to constructing a geological model of oil or other mineral deposit. In particular, the invention refers to the method, device, and machine-readable data carrier intended for evaluating the correlation coefficient for a set of well log curves and determining the position of marker depths at which the coefficient of correlation is maximal. A technical result is the improved accuracy of evaluation of parameters used in the construction of geological model describing the location of oil or other deposits. The method makes enables calculation of the depths of marker in a group of wells, given the depths to this marker in another well group used as a reference set. For any well W where the marker depth is to be determined, wells from the reference group are chosen lying at specified distance from the well W and the well with the maximal correlation coefficient is chosen among them.