Abstract: Shield apparatus are provided for use with logging instruments equipped with transverse magnetic dipole antennas. Flexible dielectric strips and dielectric cylindrical bodies are implemented with conductive elements in various patterns to form Faraday shield structures. The shields provide an extended conductive surface to the instrument support member and redirect axial currents along the borehole, protecting the underlying antennas from the undesired effects of these currents.

Abstract: A sample module for use in a downhole tool includes a sample chamber for receiving and storing pressurized fluid. A piston is slidably disposed in the chamber to define a sample cavity and a buffer cavity, and the cavities have variable volumes determined by movement of the piston. A first flowline is provided for communicating fluid obtained from a subsurface formation through the sample module. A second flowline connects the first flowline to the sample cavity, and a third flowline connects the first flowline to the buffer cavity for communicating buffer fluid out of the buffer cavity. A first valve capable of moving between a closed position and an open position is disposed in the second flowline for communicating flow of fluid from the first flowline to the sample cavity. When the first valve is in the open position, the sample cavity and the buffer cavity are in fluid communication with the first flowline and therefore have equivalent pressures.

Abstract: Determining the downhole rheological properties of a wellbore fluid. The method includes moving the wellbore fluid through a wellbore tool assembly into a wellbore at a first flow rate. A pressure is measured at a first position proximate a bottom of the wellbore. A pressure is measured at a second position in the wellbore axially separated from the first position. The wellbore fluid is then moved through the wellbore tool assembly at a second flow rate. Measuring pressure at the first and second positions is repeated, and at least one rheological property is determined from the pressure measurements.

Abstract: A straddle packer tool for treatment of wells has a tool body supporting sealing elements in spaced relation for defining a sealed annulus zone within a wellbore. The tool body defines a treatment fluid passage having treatment ports that open to the sealed annulus zone for formation fracturing or other well treatment. The tool body has a bypass passage therethrough which is isolated from the treatment fluid passage and communicates with the wellbore above and below the sealed annulus zone. A check valve permits downward flow of well fluid from the bypass passage into the wellbore below the tool and prevents upward flow of fluid into the bypass passage. Bypass ports conduct fluid flow to and from the bypass passage and the wellbore above and below the sealed annulus zone. A packer actuated bypass valve is opened or closed to control the flow of well fluid within the bypass passage.

Abstract: A shear release packer that includes at least one sealing element, at least one slip, and at least a lower shear nut. In order to release the packer, the lower shear nut is sheared enabling the at least one sealing element to de-energize and the at least one slip to disengage the casing. When set, the packer is constructed to that the lower shear nut is isolated from the load path generated by the forces acting on the at least one sealing element. The load path travels from the at least one sealing element to the at least one slip without having to travel through the lower shear nut.

Abstract: A system for separating gas from a produced fluid. The system comprises a bottom intake completion utilized in a subterranean location. The system utilizes a gas handling system that separates a gaseous component from a fluid. The gas is vented to a separate flow path, while the fluid having a lower gas content is produced to a desired location.

Abstract: A method is disclosed for determining a characteristic of a mud mixture surrounding a drilling tool within a borehole in which a drilling tool is received. The method includes turning the tool in the borehole. Energy is applied into the borehole from an energy source disposed in the tool. Measurement signals are received at a sensor disposed in the tool from a location around the borehole. The cross-section of the borehole is separated into at least a first sector and a second sector. A first measurement signal from the first sector is substantially in response to returning energy which results from the interaction of the applied energy with the mud mixture. A second measurement signal from the second sector is substantially in response to returning energy which results from the interaction of the applied energy with the formation. An indication of an intrinsic characteristic of the mud mixture is derived from the first measurement signals associated with the first sector of the borehole.

Abstract: A method is disclosed for operating a well logging tool having a controllable radiation source operatively coupled to a power source. The method includes monitoring at least one condition in a wellbore, and operatively disconnecting the power source from the radiation source when the at least one condition changes. Also disclosed is a downhole measurement assembly, which includes a radiation source, a power source, and at least one interlock operatively connected between the power source and the radiation source, where the at least one interlock is adapted to selectively arm and disarm the radiation source.

Abstract: A robust, low-loss wired pipe joint is provided for service as a component of a wired pipe string for transmitting measurement data to a surface station from locations in a borehole in oil well drilling and oil well operations. Conductive layers reduce signal energy losses over the length of the drill string by reducing resistive losses and flux losses at each inductive coupler. The wired pipe joint is robust in that it remains operational in the presence of gaps in the conductive layer. A wired pipe joint includes an elongate tubular shank having an axial bore, a threaded box-end, and a threaded pin end.

Abstract: In one aspect, the invention involves an acoustic logging tool for performing acoustic investigations of subsurface geological formations. In one embodiment, the tool comprises a generally longitudinally extending tool body adapted for positioning in a borehole. At least one transmitter is mounted on the tool body to emit acoustic energy. At least one receiver is also mounted on the tool body at a location axially displaced from the at least one transmitter. The receiver is adapted to receive acoustic energy. An attenuator is also positioned along the body and includes at least one cavity having a plurality of particles disposed therein. The attenuator as disclosed herein may be applied to other logging tools for protecting tool components and enhancing measurement quality. Methods for attenuating acoustic energy transmitted through the body of an acoustic logging tool or other logging tools are also disclosed.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: A borehole survey method is provided for processing continuous measurements of the earth's magnetic and gravitational fields obtained while drilling a borehole. The present invention improves borehole acquisition of targeted geological structures by substantially reducing continuous measurement errors attributable to noise, shock and vibrations from turning the drill bit against rock.

Abstract: This invention comprises the use of a variable orifice valve as a flow controller and flow meter. Pressure measurements are taken upstream and downstream of the variable orifice valve by way of a differential pressure measurement mechanism. The differential pressure measurement mechanism may comprise two separate absolute pressure measurement devices or a single differential pressure measurement device. Flow rate through the valve is determined from the pressure drop across the valve. In wellbores having multiple zones, a variable orifice valve together with a differential pressure measurement mechanism may be deployed for each zone. The flow rate through each of the zones and at the surface can then be monitored and controlled.

Abstract: A shielding method and apparatus for an antenna disposed on an elongated support adapted for disposal within a borehole. The shield providing predetermined attenuation of one or more electromagnetic energy field components as the field components interact with the shield. The shield composed of a flexible strip or cylindrical body and respectively comprising a transverse conductive element or a transverse slot therein. The shields being adapted to cover an antenna mounted on the support. The shields being compatible for use in conjunction with saddle, tilted coils or multi-layered tri-axial coils to produce a pure transverse magnetic dipole electromagnetic field. The shields are also used in methods for shielding an antenna disposed on a support to provide predetermined attenuation of an electromagnetic field component as the field components interact with the shield.

Abstract: A linkage apparatus for selectively gripping and releasing the inside walls of a conduit, the apparatus comprising: a first arm; a bi-directional gripping cam rotatably attached to the arm; and an extension and locking device adapted to selectively radially extend the arm from a tool housing to an inside wall of a conduit and adapted to selectively lock the arm in an extended position.

Abstract: An NMR measurement apparatus includes at least one magnet, at least one antenna, an RF pulse transmitter and a controller. The magnets) establish a static magnetic field, and the RF pulse transmitter is coupled to the antenna(e). The controller is coupled to the transmitter and the antenna(e). The controller is adapted to cause the RF transmitter to transmit RF pulse sequences into a sample and for each different RF pulse sequence, vary an estimated pulse width for producing a predetermined flip angle by a different scaling factor to produce flip angles near the predetermined flip angle. The controller is adapted to receive spin echo signals in response to the transmission of the RF pulse sequences; determine a property of the sample in response to the spin echo signals; and use the spin echo signals to determine an optimal pulse width for producing the predetermined flip angle.

Abstract: A booster to relay a detonation train from a detonating cord to another booster includes an explosive and a shell. The shell has an open end to receive an end of the detonating cord and an indented closed end that is adapted to form a projectile to strike the other booster when the explosive detonates. The explosive may include at least fifty percent by weight of NONA, and in some embodiments, the explosive may be primarily NONA.

Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.

Abstract: In order to ensure that at least some of the tools (12-1) to 12-4) in a string of tools that is permanently installed in an oil well (10) are kept in operation even in the event of a localized fault, the link (18) interconnecting the tools and a surface installation (16) is subdivided into segments by switch members (20). More precisely, a switch member is associated with each tool. In addition, the link (18) forms a loop with both ends thereof being connected to the surface installation (16).

Abstract: Systems and methods for monitoring a characteristic of a subterranean hydrocarbon reservoir and for placing a borehole in the vicinity of a well in an earth formation. New well completion systems with slotted stations are utilized to provide through-casing signal-transmission and/or reception. Hydraulic isolation between the interior and the exterior of the completion is provided by pressure barrier means at the slotted stations. The completions permit temporary or permanent monitoring of changes in reservoir saturation with the use of mobile sources/sensors. The completions also form part of a system for accurately placing a well within a desired distance and orientation relative to an existing well.