Matches 301 - 350 out of 434 < 1 2 3 4 5 6 7 8 9 >


Match Document Document Title
5406206 Method of evaluating a geological formation using a logging tool including slot antenna having two nonparallel elements  
A slot antenna has a square aperture and two current probes at angles to each other in the aperture. The two current probes are excited simultaneously or separately with different signals. By...
5402068 Method and apparatus for logging-while-drilling with improved performance through cancellation of systemic errors through combination of signals, utilization of dedicated transmitter drivers, and utilization of selected reference signals  
A logging-while-drilling system is disclosed which includes a pair of receiving antenna disposed between upper and lower transmitting antenna. The upper and lower transmitting antenna are...
5389881 Well logging method and apparatus involving electromagnetic wave propagation providing variable depth of investigation by combining phase angle and amplitude attenuation  
An electromagnetic wave propagation well logging system for measuring dielectric constant and/or formation resistivity (conductivity) includes three transmitters and a pair of receivers. The...
5373443 Method for imaging with low frequency electromagnetic fields  
A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy...
5367262 Advances in high frequency dielectric logging  
The present apparatus and method are directed to a high frequency dielectric measurement system for use in logging a well borehole. A transmitter transducer cooperative with one or more receiver...
5361239 Compensation method using a single transmitter measurement tool  
A method for borehole compensation using a single transmitter measurement electromagnetic propagation tool is disclosed. Phase shift and attenuation are measured at each of three positions...
5345179 Logging earth formations with electromagnetic energy to determine conductivity and permittivity  
A form of the disclosure is directed to determining properties of formations surrounding an earth borehole having a standoff layer. A method is disclosed for determining the conductivity and...
5341100 Electromagnetic wave method and apparatus for downhole measurement of fluid conductivity and hydrocarbon volume during formation testing  
There is disclosed in the present specification a method and apparatus for use of a downhole formation multi-tester instrument in the characterization of formation fluids, including measurement of...
5339036 Logging while drilling apparatus with blade mounted electrode for determining resistivity of surrounding formation  
Measurement-while-drilling apparatus is disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body, such as a drill collar on a...
5329235 Method for processing signals from an MWD electromagnetic resistivity logging tool  
This invention discloses an adaptive deconvolution method for enhancing the vertical resolution of an MWD (measurement-while-drilling) electromagnetic resistivity logging tool. The tool measures...
5323114 Method and apparatus for obtaining sectional information of the underground by measuring time differences and strength of electromagnetic signals  
An underground radar tomography in which an electromagnetic wave is radiated into the ground, the amplitude and propagation time of a transmitted wave, a reflected wave or a diffracted wave of the...
5298987 Method for investigating ground structure of pavement  
Method for investigating the ground structure of a paved road which requires only a small diameter boring for direct observation of the ground structure. The method comprises a step of boring an...
5278507 Well logging method and apparatus providing multiple depth of investigation using multiple transmitters and single receiver pair having depth of investigation independent of formation resistivity  
An apparatus and method for determining formation resistivity at a plurality of radial distances from an earth borehole uses a single receiver pair and a plurality of electromagnetic energy...
5260660 Method for calibrating a downhole receiver used in electromagnetic instrumentation for detecting an underground conductor  
A method utilized with an underground conductor detection system for calibrating a downhole transmitter to compensate for detuning of the transmitter antenna by geologic formations. The method...
5243290 Apparatus and method of logging using slot antenna having two nonparallel elements  
A slot antenna has a square aperture and two current probes at angles to each other in the aperture. The two current probes are excited simultaneously or separately with different signals. By...
5241273 Method for controlling directional drilling in response to horns detected by electromagnetic energy propagation resistivity measurements  
The disclosed method is applicable for use in conjunction with an earth borehole drilling apparatus that typically includes: a drilling rig; and a drill string operating from said drilling rig for...
5233522 Multifrequency dielectric logging tool including antenna system responsive to invaded rock formations  
An apparatus for induction logging is disclosed. By transmitting a sequence of pulses at many frequencies, the formation invaded zone diameter can be distinguished as a result of changes in...
5212495 Composite shell for protecting an antenna of a formation evaluation tool  
A fiber reinforced polymer matrix composite shell for covering the elastomeric layer surrounding the antenna of a measurement-while-drilling borehole formation evaluation tool is disclosed. The...
5210495 Electromagnetic logging method and apparatus with scanned magnetic dipole direction  
In a form of the disclosure, electromagnetic propagation logging measurements are made for several magnetic moment directions of the electromagnetic energy, and can be examined and/or processed...
5200705 Dipmeter apparatus and method using transducer array having longitudinally spaced transducers  
A disclosed embodiment utilizes one or more toroidal coil antennas mounted, in an insulating medium, on a drill collar to induce currents which travel in a path that includes the drill collar and...
5198770 Logging apparatus having a wall engaging pad with longitudinally aligned detecting devices  
The apparatus includes a pad (20) pressed against the wall of a borehole (12), the pad comprising a plurality of detecting devices (42, 43, 44, 45) disposed in alignment along the longitudinal...
5185578 Method for detecting anomalous geological zones by transmitting electromagnetic energy between spaced drillholes using different frequency ranges  
A method utilized with an underground conductor detection system for calibrating a downhole transmitter to compensate for detuning of the transmitter antenna by geologic formations. The method...
5168234 Method and apparatus for measuring azimuthal as well as longitudinal waves in a formation traversed by a borehole  
A new type of microwave azimuthal wave propagation, never before known to exist, provides the basis for a new formation evaluation measurement for Electromagnetic Wave Propagation Tools (EPT)....
5157331 Enhanced wide aperture groove for antenna of downhole resistivity tool  
In an electromagnetic propagating antenna circumferential groove disposed in an MWD resistivity tool mandrel and normally sealed with an epoxy resin non-conducting material forming an annular ring...
5144245 Method for evaluating a borehole formation based on a formation resistivity log generated by a wave propagation formation evaluation tool  
The method evaluates borehole formations using corrected formation resistivity logs obtained from a formation evaluation tool. In accordance with the present invention the method corrects the...
5138263 Electromagnetic formation evaluation tool  
A tool for evaluating electrical properties of an earth formation surrounding a borehole while drilling the borehole is disclosed. The tool includes a housing for connecting upper and lower...
5132623 Method and apparatus for broadband measurement of dielectric properties  
A method and apparatus measures dielectric properties over a broad range of frequencies. The functions of various resistivity and dielectric constant measuring devices such as logging tools are...
5105356 Method for curve correlation  
The maximum correlation between a pair of curves is determined from the maximum value of the common area of such curves with respect to reference lines within a select window as one of the curves...
5081419 High sensitivity well logging system having dual transmitter antennas and intermediate series resonant  
A well logging apparatus and method for measuring the resistivity of the formation surrounding a borehole is disclosed. The invention provides two transmitting antennas arranged around a housing...
5066916 Technique for separating electromagnetic refracted signals from reflected signals in down hole electromagnetic tools  
In a logging tool which transmits electromagnetic radiation into adjacent formations, and including such tools which operate as low as 20 Khz (typical for induction logs) up to as high as the...
5066917 Long feature vertical or horizontal electrical conductor detection methodology using phase coherent electromagnetic instrumentation  
A method utilized with an underground conductor detection system for calibrating a downhole transmitter to compensate for detuning of the transmitter antenna by geologic formations. The method...
5001675 Phase and amplitude calibration system for electromagnetic propagation based earth formation evaluation instruments  
A phase and amplitude calibration system for an electromagnetic propagation based earth formation evaluation tool is presented. In accordance with the present invention, improved phase and...
4994747 Method and apparatus for detecting underground electrically conductive objects  
An apparatus and method for detecting vertically or horizontally oriented underground electrical conductors such as electrical wiring or rails in tunnels thin conducting ore veins surrounded by...
RE33458 Method for constructing vertical images of anomalies in geological formations  
Apparatus and method for detecting geological anomalies occuring in geological formations. The instrumentation comprises a medium frequency continuous wave narrowband FM transmitter and receiver...
4968940 Well logging apparatus and method using two spaced apart transmitters with two receivers located between the transmitters  
Well logging techniques and apparatus are disclosed for determining formation resistivity at different radial depths of investigation and with greater accuracy than prior techniques, for...
4964085 Non-contact borehole caliber measurement  
A method and apparatus for measuring the caliber of a borehole while drilling utilizes a borehole compensated downhole measuring system in both a compensated and a non-compensated manner. A...
4958286 Time-variant filter coefficients  
There is disclosed herein an improved method for processing the output signals from the receiver coil of an induction logging tool to account for nonlinear attenuation and phase shift of the...
4949045 Well logging apparatus having a cylindrical housing with antennas formed in recesses and covered with a waterproof rubber layer  
A well logging apparatus is disclosed including a cylindrical housing with a transmitting antenna and first and second receiving antennas. The antennas are formed on insulating material in...
4940943 Method and apparatus for optimizing the reception pattern of the antenna of a propagating electromagnetic wave logging tool  
A conventional electromagnetic logging device, having both MWD and wire line embodiments, and having a pair of cutouts spaced along the length of the tool mandrel, each cutout having a length of...
4916400 Method for determining characteristics of the interior geometry of a wellbore  
A method is proposed for determining the distance from an investigating device to the surface of a medium capable of supporting wave propagation. According to the method, a propagatory wave is...
4899112 Well logging apparatus and method for determining formation resistivity at a shallow and a deep depth  
Well logging techniques and apparatus are disclosed for determining formation resistivity at different radial depths of investigation and with greater accuracy than prior techniques, for...
4893084 Formation electromagnetic parameters measuring tool using transmitter reference and reflected signals and a received signal  
A method and apparatus for dielectric investigation in formations adjacent a well borehole is set forth. In the preferred and illustrated embodiment, a microwave transmitter forms and output...
4876511 Method and apparatus for testing and calibrating an electromagnetic logging tool  
A method and apparatus for testing and calibrating an electromagnetic logging tool are described. The tool includes a tansmitting antenna and a receiving antenna. A shielded receiving device is...
4875015 Multi-array borehole resistivity and induced polarization method with mathematical inversion of redundant data  
Multiple arrays of electric or magnetic transmitters and receivers are used in a borehole geophysical procedure to obtain a multiplicity of redundant data suitable for processing into a...
4857852 Induction well logging apparatus with transformer coupled phase sensitive detector  
A well logging apparatus is disclosed which employs slot antennas having a plurality of conductive probes traversing the slot. Also disclosed are a logging apparatus having electrically isolated...
4845433 Apparatus for microinductive investigation of earth formations  
A wall-engaging apparatus for microinductively investigating a characteristic of earth formations traversed by a borehole includes an antenna set mounted in a longitudinally elongated body adapted...
4831331 Method and apparatus for interface location determination  
A method and apparatus for determining the interface between two materials having different dielectric properties, especially in determining the thickness of a hydrocarbon layer on ground water,...
RE32913 Shields for antennas of borehole logging devices  
The disclosed invention is suited for use in conjunction with a borehole logging device wherein transmitting and receiving antenna coils are wound on insulating media around the axis of a support...
4814768 Downhole pulse radar  
A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and...
4810970 Oil-based flushed zone electromagnetic well logging system and method  
An electromagnetic energy well logging system and method includes transmitting electromagnetic energy substantially at a frequency of 4 MHz into an earth formation from a borehold traversing the...

Matches 301 - 350 out of 434 < 1 2 3 4 5 6 7 8 9 >