Abstract: A system for controlling the operation of computer power and reset switches. A separate key switch enables a user to selectively disable the power and reset switches of the computer. The user has the option of operating the computer in a secured mode, in which a user key is required to actuate the power and reset switches, or alternatively in an unsecured mode in which the power and reset switches operate normally. Control circuitry is connected to the switches and operates in the unsecured mode for enabling power supply and reset circuitry operating state transitions responsive to the user actuation of the respective switches. In the secured mode, the circuitry disables the power supply state transitions that normally would occur responsive to user actuation of the first switch, and disables the reset circuitry state transitions, but only from the inactive operating state to the active operating state, so the reset circuitry is prevented from remaining in a continuous reset loop.

Abstract: A new drill stem test apparatus and corresponding method includes a dual coaxial coiled tubing adapted to be disposed in the wellbore. The dual coaxial coiled tubing includes an inner coiled tubing, and an outer coiled tubing surrounding and enclosing the inner coiled tubing and forming an annular space which is located between the inner coiled tubing and the outer coiled tubing. The annular space is adapted to contain a pressurized kill fluid. A first end of the outer coiled tubing is sealed by a sealing element to a first end of the inner coiled tubing, the end of the inner coiled tubing extending beyond the sealing element and adapted to receive a formation fluid. The first ends of the inner and outer coiled tubing are disposed in a wellbore. A second end of the inner and outer coiled tubing is wound onto a coiled tubing reel and is connected to a kill fluid valve and a formation fluid valve.

Abstract: A deflecting tool or whipstock is oriented and anchored in a well casing during a single trip of a running string so that a window can be formed in the wall of the casing at a selected azimuth. The angular orientation of the deflecting tool is measured, and signals representative thereof are transmitted to the surface. When the desired orientation is obtained, the anchor is actuated to prevent movement of the deflecting tool, and the orientation adjusting and measurement and transmission tools are released from the whipstock and removed from the casing by withdrawing the running string which preferably is coiled tubing. Then a downhole motor and milling bit are run into the casing on coiled tubing and operated to form a window through the wall thereof opposite the deflection surface of the whipstock so that a new borehole can be drilled outside the casing.

Abstract: This invention provides a method and system for logging an earth formation with a logging tool that is stuck (lodged) in a well bore traversing the earth formation while fishing for the stuck logging tool. This procedure is accomplished by re-establishing communication between the stuck logging tool and surface equipment during the fishing process. Communication is established by reconnecting the electrical conductors in the supporting cable after the cable has been severed in order to install fishing equipment in the well bore around the cable supporting the logging tool. The procedure to reconnect the electrical conductors requires identifying conductors in each end of the severed cable and appropriately matching conductors from each cable end to achieve electrical communication. Once there is electrical communication between the stuck logging tool and surface logging equipment, logging procedures can be continued even during the fishing for the stuck logging tool.

Abstract: An acoustic transducer comprises two pairs of opposite elongate segments (20) placed inside a deformable tube (14). Drive means (22) operable to expand in a direction orthogonal to the axis of the tube are disposed between the segments of each pair. The drive means occupy a substantial portion of the inside volume of the tube. A preferred arrangement includes drive means for a pair of segments longitudinally displaced from the drive means for the other pair. Drive means may be constituted by stacks of piezoelectric pellets (24) extending radially relative to the axis of the tube. A pressure compensation system is provided to keep the pressure inside the tube (14) substantially equal to the external pressure. Longitudinal flutes (14a) are formed inside the tube (14) between the segments (20) to facilitate tube deformation and amplify volume variation.

Abstract: A method and apparatus of monitoring subsurface formations containing at least one fluid reservoir and traversed by at least one well, by means of at least one sensor responsive to a parameter related to fluids, comprising the steps of:lowering the sensor into the well to a depth level corresponding to the reservoir;fixedly positioning said sensor at said depth while isolating the section of the well where the sensor is located from the rest of the well and providing fluid communication between the sensor and the reservoir.

Abstract: A new interpretation system receives a low resolution log and a high resolution log from a well logging tool that is disposed in a wellbore which traverses a highly laminated formation and generates an output record medium which clearly illustrates and quantifies each layer of the plurality of layers of the laminated formation. In response to receipt of the low and high resolution logs, the new interpretation system generates a rectangular deconvolved log. The rectangular deconvolved log is generated by first selecting a plurality of modes or possible formation types from a histogram. Each of the plurality of modes are then solved, in a least squares sense, by minimizing the sum, over a particular depth interval in the wellbore, of the square of the residual between the tool measurement and the reconstructed log, a calculation which is equivalent to solving a system of N equations and N unknowns.

Abstract: A method for measuring formation density corrected for activated gamma radiation. The formation adjacent the borehole is irradiated with low energy gamma radiation from a density tool source. At least one gamma ray detection means is spaced longitudinally from the source. A gamma ray spectrum containing gamma rays that result from density source radiation and also activated gamma rays is detected by the detection means. The activated gamma rays are identified and subtracted from the total number of detected gamma rays which results in the gamma ray count from the density tool source. This gamma ray count can then be used in conventional density calculation processes to determine formation density that has been corrected for activated gamma rays caused by naturally occurring gamma radiation and from other logging equipment that induces gamma radiation.

Abstract: A system includes a wellbore tool disposed in a wellbore and a surface apparatus disposed at a surface of the wellbore. Prior to operating the tool to take an initial measurement, the wellbore tool is first calibrated to take into account magnetic junk which is magnetically attracted to and accumulated on a magnet housing of the tool. To calibrate the tool, a new tuning frequency, called the Larmor frequency, is determined, and the tool is tuned to the new Larmor frequency before taking an initial measurement. The wellbore tool and the surface apparatus each include a processing system. Each processing system includes a memory. A first part of a tuning frequency determination software is stored in the memory of the tool, and a second part of the frequency determination software is stored in the memory of the surface apparatus. To determine the tuning frequency, the processing system in the wellbore tool initiates execution of the first part of the tuning frequency determination software.

Abstract: A method of monitoring formation fractures in real-time is performed in which a fluid containing a radio-active tracer element is pumped at a high pressure down a wellbore into a formation. As the fluid creates fractures and moves through the formation gamma-rays are emitted from the radio-active tracer element in the fluid. Detector means placed at predetermined locations in the wellbore continuously detect these gamma-rays. Gamma-rays emitted from wellbore fracture fluids are distinguished from formation gamma-rays and the detected formation gamma-rays are counted. As the fracture fluid approaches the height or vertical depth of these detecter means, the gamma-ray count increases. Once the gamma-ray count reaches a predetermined level, the fracture will have reached a desired location in the formation and pumping of the fracture fluid will stop.

Abstract: A reinforcing slat for use in an inflatable packer which is elongate and curved about its longitudinal axis and comprises perforations in the part thereof which enters the end portion and which bends around the end portion on inflation of the packer. The perforations serve to reduce the bending stiffness of the slat in the portion likely to suffer permantent deformation on inflation of the packer.

Abstract: NMR logging apparatus is provided which produces a strong, static and homogeneous magnetic field B.sub.0 in a Volume of an adjacent formation on one side of the tool to measure nuclear magnetic resonance characteristics thereof at two different depths of investigations. In the preferred embodiment, the tool has an RF antenna mounted on the outside of the metal body of the tool, directing focused oscillating magnetic fields B.sub.1 at said Volume to polarize or tip the magnetic moments of hydrogen nuclei of fluids within rock pores. The same antenna can be used to receive signals of proton precession in the Volume of interest immediately after transmission of the RF polarizing field B.sub.1. One of the NMR readings is employed to compensate for inaccuracies in the other NMR reading to provide an overall improved NMR log.

Abstract: Methods and systems for forming a window through the wall of a well casing to enable a new borehole to be drilled outside the casing include forming a cement plug in the casing, drilling a laterally offset hole in the cement plug, orienting and setting a whipstock in the offset hole, and using the whipstock to drill an elongated window through the casing wall opposite its deflector surface. The drilling steps employ a mud motor having a bent housing that establishes a toolface for the bit, and proper orientation is obtained by downhole measurement and transmission to the surface of orientation signals and downhole adjustment of orientation to a selected toolface value. The whipstock is oriented in the same manner. All drilling and orientation procedures are carried out on coiled tubing to reduce costs.

Abstract: A wellbore tool includes an anchor connected to a perforating gun, the anchor including an anchor slip disposed between upper and lower slip housings for expanding to grip a casing in the wellbore, a primary anchor release mechanism for unsetting the anchor slip and a secondary anchor release mechanism for unsetting the anchor slip when the primary anchor release mechanism is not activated. If the primary and secondary anchor release mechanisms have not been activated, the anchor slip can be set. The primary anchor release mechanism automatically unsets the anchor slip when a detonation wave, conducting in a detonating cord, propagates through an interior space of a frangible member, the detonation wave shattering the frangible member and detonating the perforating gun. When the frangible member is shattered, the anchor slip can then be unset thereby allowing the perforating gun to fall to a bottom of the wellbore.

Abstract: A tubular connector for connecting a drilling tool assembly to a drill string for use in CTD operations. The connector has a fluid flow passage therethrough, and comprises: a first part connected to the drill string and a second part connected to the drilling tool assembly; inter engaging formations such as splines provided on the first and second parts such that, when engaged, the formations do not prevent relative axial movement of the first and second parts but prevent relative rotation thereof; a threaded collar provided around adjacent end portions of the first and second parts for axial location thereof when connected. The connector can also include a non-return valve assembly located in the fluid flow passage; a pressure actuated piston device in the fluid flow passage for disconnecting the drilling tool assembly from the chill string; and a pressure actuated valve which, when operated, allows fluid communication between the fluid flow passage and an exterior region of the connector.

Abstract: Improved fluid loss control in gravel pack placement fluids is achieved when a fluid loss control additive is provided comprising a selectively soluble particulate having a size of less than 1000 microns and having a linear size distribution when cumulative weight percent is plotted against the logarithm of the particle size. The preferred selectively soluble particulate comprises calcium carbonate.

Abstract: A shaped charge includes a case, an explosive material packed against the inner wall of the case, and a liner for lining the explosive material, where the liner includes Bismuth and Copper powders as constituent elements. The Bismuth element replaces a Lead element which is normally present as a constituent element in prior art shaped charge liners. Bismuth is superior to Lead because all environmental concerns, with respect to the deposition of Lead in a formation, have been eliminated.

Abstract: A method and apparatus for detecting natural gamma-ray signals of an earth formation and correcting these gamma-ray signals for effects from borehole gamma-rays. Gamma-ray signals are detected at two detector locations in the borehole. The borehole effects are derived from the differences between the detected signals. After the borehole effects are determined, the detected gamma-ray signal is corrected for these effects and measurements of the formation elements are derived. A differential signal between the two detectors is created by excluding a small volume of borehole fluid from one of the detectors from the borehole fluid, before detecting gamma-rays at both detectors. The excluder displaces a known volume of borehole fluid equal to the volume of the excluder. Both detectors record gamma-ray generated from the formation and borehole. The additional volume of borehole fluid at one detector causes the detected signals to be different.

Abstract: A spontaneous potential (SP) sub is interconnected between two metallic housings of a wellbore apparatus and is lowered into a wellbore. A spontaneous potential (SP) of an earth formation trasversed by the wellbore is measured by the SP sub, and a log is generated from the sub which is representative of the spontaneous potential of the formation, the log being substantially free of a special type of distortion which typified the prior art SP measurements taken by prior art SP measurement apparatus. The SP sub includes a measurement electrode, monitoring electrodes placed on both sides of the measurement electrode, a bucking electrode placed on both sides of the monitoring electrodes, current driving circuitry connected to the bucking electrodes, and receiving circuitry connected to the monitoring electrodes. The current driving circuitry delivers a current of sufficient magnitude to each bucking electrode such that the voltage potential between the monitoring electrodes is approximately equal to zero.

Abstract: In order to enable information such as the results of physical measurements performed downhole in an oil well during testing or production to be transmitted in real time to a receiver on the surface, the bottom portion of a tubular string (12) is fitted with a transmitter device that transmits an electromagnetic wave which is conveyed to the receiver on the surface by the ground surrounding the well. The transmitter device includes a power source (32) disposed in an annular cavity (34) formed at an intermediate level between an outer insulating coupling (36) and an inner insulating coupling (38). The power source (32) is electrically connected between two tubular walls (39, 40) delimiting the cavity (34) so as to apply a modulated alternating electrical signal directly to said walls.