3789 results about "Well logging" patented technology

A transmitter antenna assembly for transient electromagnetic well logging instrument comprises an antenna coil coupled with a current source and a magnetic core having residual magnetization. Switching current in the antenna coil results in magnetization reversal in the magnetic core and change in magnetic dipole moment of the antenna. After the magnetization reversal is complete the current is removed and the new vector of magnetic dipole of the antenna maintains constant (steady-state phase of the antenna dipole) due to magnetic hysteresis of magnetic material employed for the magnetic core. No power expenditure during the steady-state phase of the magnetic dipole facilitates highly effective generation and fast switching of a large magnetic dipole. The magnetic core also serves as a shield between the antenna coil and any conductive part of the antenna assembly. Embodiments suitable for measurement-while-drilling or measurements through casing make use of residual magnetization of magnetic drill collar or magnetic casing respectively.

A method and apparatus for evaluating the resistivity of earth formations surrounding a borehole, particularly high-contrast thin-layer formations or at high dip angles. The method involves positioning a pair of transmitters and a pair of receivers within the borehole, the receivers or transmitters adhering to specific spacing limitations, alternately transmitting electromagnetic energy of a particular frequency and receiving voltage data associated with the transmitted energy. Multiple voltage data are acquired and a representation of a resistivity or conductivity profile is created from a formulated difference of the data from a particular depth and/or neighboring depths. The apparatus forms part of a well logging system including a well tool adapted to be moveable through a borehole. The apparatus being coupled to the well tool and adapted with means to input voltage data developed by the receivers disposed on the well tool. The apparatus further adapted with means for performing calculations to determine a conductivity profile and for recording the profile on an output record medium.

An apparatus and method for obtaining facies of geological formations for identifying mineral deposits is disclosed. Logging instruments are moved in a bore hole to produce log measurements at successive levels of the bore hole. The set of measurements at each such level of the bore hole interval is associated with reference sample points within a multidimensional space. The multidimensional scatter of sample points thus obtained is analyzed to determine a set of characteristic modes. The sample points associated with characteristic modes are grouped to identify clusters. A facies is designated for each of the clusters and a graphic representation of the succession of facies as a function of the depth is thus obtained. To identify the clusters, a "neighboring index" of each log measurement point in the data set is calculated. Next, small natural groups of points are formed based on the use of the neighboring index to determine a K-Nearest-Neighbor (KNN) attraction for each point. Independently of the natural group formation, an optimal number of clusters is calculated based on a Kernel Representative Index (KRI) and based on a user-specified resolution. Lastly, based on the data calculated from the prior steps, final clusters are formed by merging the smaller clusters.

An electromagnetic wave propagation resistivity borehole logging system comprising multiple groups of electromagnetic transmitter-receiver arrays operating at three frequencies. The borehole logging tool component of the system employs eight transmitters and four receivers. The transmitters and receivers are disposed axially and symmetrically along the major axis of the tool to form four group pairs. Each group pair consists of a transmitter-receiver groups axially and symmetrically on opposing sides of a reference point on the tool. Each, transmitter-receiver group consists of one transmitter assembly and two receiver assemblies. Each transmitter-receiver group is operated at two of three operating frequencies which are 100 kHz, 400 kHz and 2 MHz. Some of the transmitter and receiver assemblies are fabricated to yield azimuthally focused resistivity measurements, and to yield vertical and horizontal resistivity in anisotropic dipping beds. The system can be embodied as a logging-while-drilling system or as a wireline logging system.

A well logging cable including an optical fiber and a pressure sealed enclosure surrounding the fiber. The enclosure is adapted to be able to be elongated to the maximum expected axial strain on the logging cable without permanent deformation. In one embodiment, the enclosure is a corrugated-wall tube surrounding the optical fiber. The tube contains toroidally shaped rings within the maximum diameter portions of the corrugations in the tube wall. The cable includes armor wires wound around the corrugated-wall tube. In the preferred embodiment, the tube is surrounded by an elastomeric jacket, and is filled with hydraulic oil or the like to prevent entry of wellbore fluids into the tube under hydrostatic pressure.

A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or from inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

A model system for simulating the performance of a subterranean well, starts with a base model wherein input logging data, pressure transient data and PVT data is introduced into the base model. A numerical interpreter then calculates the predicted performance of the well. A match system compares actual performance data with calculated performance data based on the base model through reiterative loop for modifying the base model to provide a match between the actual performance data and the predicted performance data to optimize the base model. The method for generating the optimized performance data in accordance with the subject invention incorporates the steps of introducing known pressure transient data, well logging data and PVT data for the well into a base model and producing a performance prediction from the base model. These results are compared with actual performance data and the model is modified to generate a performance prediction that matches the actual performance for producing an optimized model. The method is particularly useful because it accounts for and adjusts the performance prediction based on non-Darcy factors effecting the fluid parameters in the well.

The present invention provides a method and apparatus for acoustic position logging ahead of a drill bit. The method and apparatus comprise a bottomhole assembly (BHA) conveyed on a drilling tubular in a borehole within an earth formation. The BHA has a source array for emitting preselected acoustic signals into the earth formation, and at least one receiver on the BHA for receiving a second acoustic signal produced by an interaction of the preselected acoustic signal with said formation. The source array for acoustic energy may be configured as an axially distributed array of axially or azimuthally directed sources, or an azimuthally distributed array of axially or azimuthally directed sources. The sources may be activated according to preselected time delays. The emitted acoustic signal is differing in spectrum and/or wave mode from the acoustic energy of a rotating drill string.

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.

A system and method of interpreting well log isotopic information in a drilling operation of a target area. The method begins by inputting a template for indicating a trend from analyzed mud gas samplings into a computing system. Next, a plurality of mud gas samplings are profiled through a well bore at a plurality of incremental depths of the well bore. The plurality of gas samplings are analyzed to obtain a plurality of isotopic data points associated with hydrocarbon isotopic composition of the plurality of gas samplings. The plurality of isotopic data points includes data associated with a composition of ethane and methane or other gaseous components within each of the mud gas samplings. A trend associated with the template is determined by the computing system from the plurality of isotopic data points. The plurality of isotopic data points is analyzed to geochemically interpret the geological information.

An autonomous system for performing a well operation at a predetermined location in a wellbore comprises a tool string having at least one well tool, a motive device for traversing the wellbore, and a control system adapted to position the tool string near the predetermined location. The control system comprises (i) a sensing system for detecting mass irregularities in the wellbore and (ii) a processor system having a processor with memory for storing at least one well log. The processor acts under programmed instructions to compare sensor signals to the stored well log to determine a tool string position in the wellbore. The control system also contains circuits for controlling the operation of the well tool and the motive device.

Method for assessing hydrocarbon source rock potential of a subsurface region without well log information. The method uses surface electromagnetic (121) and seismic (122) survey data to obtain vertical profiles of resistivity and velocity (123), which are then analyzed in the same way as well log data are analyzed by the well known DeltaLogR method (124).

A method for determining a formation fluid property includes acquiring a suite of nuclear magnetic resonance (NMR) measurements of a fluid sample using a pulse sequence that includes pulsed field gradient pulses for encoding diffusion information, wherein each NMR measurement in the suite is acquired with a different value in a parameter in the pulsed field gradient pulses for producing a different diffusion effect, wherein the acquiring is performed in a formation fluid sampling tool in a borehole; inverting the suite of NMR measurements to produce a distribution function that relates diffusion properties of the fluid sample with an NMR property of the fluid sample; and determining the formation fluid property from the distribution function.

The present invention discloses a method for evaluating shale gas reservoirs and searching sweet spot regions, which includes steps as follows: drilling corestone columns with different directions and measuring dynamic and static parameters of the corestone columns after saturation to obtain a transformable relational expression of dynamic and static elasticity modulus, processing physical simulation of anisotropic rocks, and calculating elastic parameters; intersecting to obtain related relationship corresponding to elastic and sensitive parameters or the combination of the elastic and sensitive parameters and parameters of shale gas sweet spot regions, getting and predicating the parameters or parameter combination of the shale gas sweet spot regions; correcting log data to obtain optimal well log; utilizing multi-mineral analysis and corestone test analysis methods to obtain a model and processing in series; inverting three-dimensional high resolution post-stack seismic data; synthesizing obtained various favorable parameters of the shale gas reservoirs and combining the accurate burial depth, thickness, occurrence and planar distribution of the shale gas reservoirs to obtain the gas bearing characteristic prospect of the shale gas reservoirs and outline the sweet spot regions for shale gas exploration and development.

The invention discloses a simulating method of the forming process of an unconventional oil and gas reservoir hydraulic fracturing complex fracture net. The method includes the steps of a, reestablishing natural fracture distribution, estimating the properties of natural fractures, obtaining rock mechanical information and stratum stress information of a stratum from log data or a geological model, and obtaining a data file related to the well factory construction process; b, inputting the obtained parameters in an established natural fractured reservoir fracturing model coupling a well cylinder, fractures and the stratum; c, conducting numerical value solving on the model to obtain after-fracturing information such as fracture forms, opening degree distribution and pressure intensity distribution; d, analyzing the fracturing effect through a model calculating result, and making a preparation for numerical value simulation of the later-period production process. The fractured reservoirfracturing numerical value simulating method coupling the well cylinder flowing, the fracture deformation expanding, the multi-state natural fractures and the flowing of fluid in the fractures can quantitatively analyze the form of the unconventional reservoir segmented volume fracture net and is an effectively means for evaluating and optimizing the fracturing scheme.

A system and method for generating a neural network ensemble. Conventional algorithms are used to train a number of neural networks having error diversity, for example by having a different number of hidden nodes in each network. A genetic algorithm having a multi-objective fitness function is used to select one or more ensembles. The fitness function includes a negative error correlation objective to insure diversity among the ensemble members. A genetic algorithm may be used to select weighting factors for the multi-objective function. In one application, a trained model may be used to produce synthetic open hole logs in response to inputs of cased hole log data.

Measurements made with a multicomponent logging instrument when used in a substantially horizontal borehole in earth formations are diagnostic of the direction of beds relative to the position of the borehole. When the logging instrument is conveyed on a drilling assembly, the drilling trajectory may be maintained to follow a predetermined trajectory or to maintain a desired distance from a boundary such as an oil-water contact.

The invention relates to an Archie mode method for determining oil layer initial oil saturation, comprising the following steps: (1) inspecting the structure of oil pool and the geological condition of a reservoir bed, and collecting relevant sampling data; (2) correcting initial oil saturation and initial water saturation data; (3) calculating the average value of the initial oil saturation or the initial water saturation according to a downhole single sand layer, namely, a substratum; (4) calculating the average value of average degree of porosity according to the single sand layer, namely, the substratum, and reading the corresponding stratum deep direction-finding resistivity data by well logging curve; (5) collecting the data and drawing; (6) establishing the Archie mode of different reservoir bed types for a single layer with approximate reservoir bed deposition and oil pool and reservoir formation characteristics; and (7) calculating the initial oil saturation for the unsampled oil layer requiring the calculation of the initial oil saturation by using the Archie saturation formula. The initial oil saturation calculated by applying the method has high precision.

Data are acquired using multi-array logging tool in a borehole having an angle of inclination to a normal to the bedding plane of earth formations. The multi-array measurements are filtered using angle dependent filters to give a filtered curve corresponding to a target one of the multi-array measurements using angle dependent filters. Correlation coefficients are determined for a set of possible dip angles and a relative dip angle is estimated from the correlation coefficients. This dip angle estimate together with bed boundaries obtained from the multi-array measurements are used for inverting multi-component measurements alone or jointly with multi-array measurements to refine the relative dip angle interpretation and give horizontal and vertical formation resistivity.

Methods and apparatus for performing sonic well logging within a wellbore based on optical Distributed Acoustic Sensing (DAS) are provided. A sonic well logging system based on DAS may be capable of producing the functional equivalent of tens, hundreds, or even thousands of acoustic sensors. In this manner, the emplacement of the sonic well logging system based on DAS may not be nearly as complex or expensive as emplacing a sonic well logging system based on traditional methods. Furthermore, multiplexing may be simpler, downhole electronics need not be used, and the sonic well logging system may be used in extreme, high temperature environments.