Abstract: A neutron generator and method of constructing the same. The generator includes a grid configured to produce an ionizable gas when heated by electrons impinging thereon. A cathode emits electrons to heat the grid and to collide with produced ionizable gas atoms to generate ions. Neutrons are generated from a collision of ions impinging on a target in the generator. A tool for subsurface use incorporating the neutron generator.

Abstract: An accelerator-based neutron tool is provided. The tool includes a deuterium-tritium gas mixture such that the tool outputs a desired ratio of 2.45 MeV and 14 MeV neutrons.

Abstract: Apparatus and method for detecting subsurface radiation phenomena. An elongated support member, adapted for disposal within a wellbore traversing a subsurface formation, includes a recess along its longitudinal axis. A pad is linked to the support member. The pad is configured with a surface correspondingly shaped to fit in juxtaposition with the support member recess. The pad is adapted for movement into and out of the recess such that an exposed surface of the pad can extend away from the support member. The pad also includes one or more radiation detectors and is adapted with shielding material on its sides near the exposed surface to prevent radiation reflected from the recess from reaching the detector(s) from the area near the exposed surface.

Abstract: A method is disclosed for estimating a formation pressure using a formation tester disposed in a wellbore penetrating a formation, said method comprising: (a) establishing fluid communication between a pretest chamber in the downhole tool and the formation via a flowline, the flowline having an initial pressure therein; (b) moving a pretest piston in a controlled manner in the pretest chamber to reduce the initial pressure to a drawdown pressure during a drawdown phase; (c) terminating movement of the piston to permit the drawdown pressure to adjust to a stabilized pressure during a build-up phase and measuring simultaneously in relation to time, pressure P(t) and temperature T(t) in the pretest chamber; (d) extracting an index i(t) dependent of the pressure P(t) and the temperature T(t) informing on the build-up phase; (e) analyzing index i(t) and repeating steps (b)-(d) or going to step (f); (f) determining the formation pressure based on a final stabilized pressure in the flowline.

Abstract: A probe 1 for measuring the electromagnetic properties of a down-hole material MC, GF, DM of a well-bore WB comprises a metallic pad 2 in contact with the down-hole material. The pad 2 further comprises an open-ended coaxial wire 4 coupled to an electronic circuit 3. The open-ended coaxial wire 4 comprises an inner conductor 4A sunk in an insulator 4B and is positioned sensibly perpendicularly to the well-bore wall. The electronic circuit 3 is able to send a high-frequency input signal into the open-ended coaxial wire 4 and to determine a reflection coefficient based on a high-frequency output signal reflected by the open-ended coaxial wire 4.

Abstract: A marine measurement system is disclosed for obtaining measurements in an underwater operating environment. The system includes a base structure having a top surface, a bottom surface, and cavities provided therebetween. The cavities are also open to the top surface. The measurement system further includes measurement equipment (e.g., electronic equipment and/or instrumentation), which are retained in the cavities. A diaphragm membrane is applied adjacent the top surface and seals the cavities. The diaphragm member is positioned in pressure communication with the operating environment. Furthermore, the cavities are defined by the membrane and the base structure and filled with a pressure compensating fluid that is in pressure communication with the operating environment through the diaphragm membrane.

Abstract: A system for handling a radioactive source includes a container containing a radioactive source and a cap mounted on the container to retain the radioactive source inside the container. The cap has a first locking structure and a second locking structure. The system further includes a handling tool having a support shaft, a first locking tip adapted to form a first lock with the first locking structure, and a second locking tip adapted to form a second lock with the second locking structure. The first and second locking tips are slidably coupled to the support shaft.

Abstract: Systems and methods for cooling a component within a housing adapted for subsurface disposal using a vortex tube. The housing contains a first pressure chamber; a vortex tube coupled to the first pressure chamber; a cooling chamber coupled to the vortex tube; and a second pressure chambercoupled to the cooling chamber; wherein the pressure chambers are adapted to stimulate a cool fluid flow from the vortex tube into the cooling chamber. A cooling method entails disposing the component to be cooled within the cooling chamber and adapting the system pressure chambers to stimulate a cool fluid flow from a vortex tube into the cooling chamber.

Abstract: The invention concerns an apparatus for investigating the wall of a borehole tilled with non-conductive mud, said apparatus comprising: a pad having an inside face and an outside face for pressing against the wall of the borehole; a set of measurement electrodes mounted on the outside face of the pad, potentials differences being measured between said measurement electrodes in order to provide measured points representative of the resistivity of the formation; both a source electrode and a return electrode adapted to inject current into the formation, the set of measurement electrodes being situated between the source electrode and the return electrode.

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 pumping system (13) for oil wells (1) comprises a pump (20) immersed at the bottom of the well (4) and a flow-meter (32) associated with the pump (20), the immersed pump (20) being supplied by an electric supply source (26). The flow-meter (32) is an electromagnetic flow-meter, also electrically supplied by the supply source (26) of the pump.

Abstract: The present invention relates to a user-guided dip picking method from electrical borehole images using Hough Transform. It includes defining a top and bottom reference curve, applying the Hough Transform to the borehole image limited by the top and bottom reference dips so that the Hough Transform space is restrained in the neighborhood of the reference dips. A 1D average trace representing the extrema of the 3D Hough parameter space for each depth is then computed and the extrema exceeding a given threshold are search in this 1D trace. The position in the 3D Hough space of an extremum represents a dip event.

Abstract: The invention provides a more efficient way to transfer data to or from a logging tool during a drilling process. A memory module is provided for rapid insertion and retrieval from a logging while drilling tool between drilling runs. The memory module records and stores data collected during the drilling process. A process of the invention includes removing the memory module from the tool; loading a new memory module into the tool that contains the desired tool parameters for the next run. The retrieved memory module is then connected to an independent surface system to download the stored data.

Abstract: An acoustic detection of a discrete acoustic signal allows to detect a leak behind a casing (23) of a borehole. An acoustic amplitude (AA) is sampled during a recording time period (24; 64) at a determined position along the tube. Time intervals (26; 66) are defined inside of the recording time period (24), and for each time interval (26) the measured acoustic amplitudes are processed to obtain respectively a corresponding power-frequency spectrum (261). A plurality of the power-frequency spectra are analyzed to identify the discrete acoustic signal by detecting time and frequency dependant changes of power. Preferably the processing involves a Fourier transform analysis. A power-frequency time plot is used to conveniently identify the discrete acoustic event.

Abstract: A system for determining a subsurface parameter from a drilled wellbore includes a casing, a logging tool comprising one or more logging devices, and a latching device coupling the logging tool to the casing such that the logging tool hangs below the casing when the casing is disposed in the wellbore. A method of determining a subsurface parameter includes disposing a casing in a wellbore, coupling the logging tool to the casing such that the logging tool hangs below the casing, and running the casing along the wellbore, wherein the logging tool makes measurements as the casing is run along the wellbore.

Abstract: A method and apparatus are useful for decomposing a complex distribution of data by modeling the complex distribution as a sum of discrete simple distributions, and processing the simple distributions independently. The independent processing enables the complex distribution to be reconstructed without the simple distributions that are concluded to be spurious. The simple distributions preferably include one or more statistical distributions that are subject to being characterized by a reduced data set for efficient communication and reconstruction of the complex distribution. The modeling and processing steps preferably employ one or more evolutionary algorithms.

Abstract: A method is disclosed for locating a receiver in a borehole having a conductive liner by inducing an electromagnetic field from a transmitter in a first borehole, detecting at a first location by at least one receiver located in a second borehole having a conductive liner, a first electromagnetic field induced by the transmitter, detecting at a second location by the at least one receiver, a second electromagnetic field induced by the transmitter and calculating a set of geometry coordinates for the first location based on the first electromagnetic field and the second electromagnetic field.

Abstract: A sensor for measuring mud resistivity in a borehole includes a transmitter having a magnetic moment in a first direction; and a receiver having a magnetic moment in a second direction, wherein the first direction and the second direction are substantially different, wherein the transmitter and the receiver are disposed in an insulating collar of a downhole tool, and wherein the transmitter is disposed at a selected distance no more than 10 inches from the receiver along a longitudinal axis of the downhole tool.

Abstract: A method for evaluating formation fluids includes measuring a nuclear magnetic resonance property related to a total volume of the formation fluids, measuring a dielectric property related to an electromagnetic wave travel time, measuring a bulk density, and solving a set of linear response equations representing a reservoir fluid model to determine fractional fluid volumes from the nuclear magnetic resonance property, the dielectric property, and the bulk density.

Abstract: A resistivity logging sensor for logging while drilling a well using an oil-based mud includes a sensor body; a first current injector electrode disposed on the sensor body, wherein the first current injector electrode is electrically insulated from the sensor body; at least two current return electrodes disposed on the sensor body at a selected distance from the first current injector electrode, wherein the at least two current return electrodes are disposed proximate to each other and are electrically insulated from the sensor body; and an electrical source configured to energize the first current injector electrode with a current having a voltage of no less than 50 mvolts and a frequency of no less than 1 KHz.