Abstract: A remotely operable downhole basket for use at the bottom of a fishing string in a well bore has a tubular body. Inside the tubular body is a tubular finger basket having a plurality of slots in which fingers are pivotally mounted. The fingers are normally biased out of the slots into horizontal positions. At the bottom of the tubular body is a tubular opener. The outer side of the tubular opener is in a vertically sliding relationship with the inside wall of the tubular body. The opener is configured at its upper end to push the fingers into their respective slots. The tubular opener has an actuator shoe at the lower end of the tubular opener. The top end of the actuator shoe is adapted to abut against the lower end of the tubular body to stop upward travel of the opener relative to the tubular body. A circular return spring is positioned between the outer side of the tubular opener and the inside wall of the tubular body.

Abstract: An inertial borehole survey system is disclosed. The survey system of the present invention includes a probe suitable for insertion into a borehole. The probe includes a plurality of temperature sensitive inertial measuring instruments which are utilized to survey the borehole during the descent or ascent of the probe. Accuracy of these instruments is maintained by enclosing the instruments in a thermal insulating package and by providing a mass of isothermal heat absorbing material which exhibits a phase change at a temperature well above most ambient temperatures. In a preferred embodiment of the present invention, a heat absorbing material is utilized which exhibits a phase change at a temperature of 116.degree. F. The probe also includes a longitudinal air passage which permits ambient temperature air to be utilized to cool the isothermal heat absorbing material by passing air through the length of the probe.

Abstract: A borehole survey instrument is provided which includes a meniscus type floating compass member for indicating azimuth and inclination. A light source is disposed below the indicia for illuminating the indicia upwardly through the liquid in which the compass member floats and a novel lens system is provided for focusing the image of the illuminated compass member upon a film disposed below the compass member and for transmitting illumination to the compass member. The compass member is mounted on a centering post which is of minimum diameter consistent with the required rigidity and which permits high angle compass members to be utilized to indicate angles approaching ninety degrees. In a preferred embodiment of the present invention, the lens system has a refractive index closely matching that of the liquid surrounding the floating compass member to minimize reflection or refraction at the inner face therebetween.

Abstract: A borehole survey instrument is provided having a meniscus type floating compass member with indicia thereon for indicating azimuth and inclination. A light source is disposed below the indicia for illuminating the indicia upward through the liquid through which the meniscus type floating compass member floats. A lens system is provided for focusing the image of the illuminated compass member upon a film disposed below the compass member. This arrangement permits the centering post for the compass member to be of minimum diameter consistent with rigidity requirements and permits a high angle compass member to indicate angles of inclination approaching ninety degrees. A multiple light bulb light source is utilized and each light bulb is mounted in a manner which permits a single light bulb to illuminate the entire compass member.

Abstract: A borehole survey instrument and control circuitry are described. The borehole survey instrument includes indicators for measuring angle of deviation from the vertical and angle of deviation from magnetic north and a photographic recording means for recording the output of the indicators at selected times. A lighting system is utilized in conjunction with the photographic recording means to expose photographic film and a novel time control circuit is utilized in conjunction with the lighting system to alter the length of time of illumination in accordance with the operativeness of individual bulbs within the lighting system. In this manner, the failure of one or more bulbs within the lighting system will not substantially affect the amount of illumination to which the film in the photographic recording means is exposed.

Abstract: A system and method for surveying, with accuracies better than one foot per thousand feet of depth, very deep boreholes having the attendant small diameters, high temperatures and high pressures with very high accuracy. A downhole probe is used having a small diameter, less than about four inches. Three linear type accelerometers and at least two gyros to provide three sensitive axes are fixedly mounted at points spaced along the axis of an elongated, rigid, thermally conductive support member to form an instrument cluster. Signals from these instruments are then processed and transmitted serially over a conductor of a conventional wireline to the surface unit where a surface computer continuously computes and records the current position of the instrument.

Abstract: A tongs having gripping jaws and a handle for applying an actuating force thereto is characterized by a sensing unit mounted in a force-receiving relationship with the handle. The sensing unit is responsive to a compression or tension force imposed thereon when an actuating force is applied to the handle to generate a signal functionally related to the magnitude of the actuating force. A readout device may be connected to the sensing unit and responsive to the signal generated therefrom to provide a visual indication in any predetermined units of the magnitude of the force imposed on the handle or the torque imposed by the jaws resulting therefrom.

Abstract: A reversible baffle plate for receiving and supporting a bottom hole survey apparatus on the interior of a directional drilling string is characterized by concentrically disposed inner and outer members supported one from the other by a plurality of webs. The webs cooperate with the inner and outer members to define a plurality of flow passages through the baffle plate. The first and second axial ends of the inner tubular member are each adapted to receive and support the lowermost axial end of a bottom hole survey apparatus.

Abstract: A bottom hole survey apparatus is characterized by a survey instrument having a reference line therein, the instrument being receivable by the engagement of flanges provided along the instrument into keyways provided on the interior of a non-magnetic instrument barrel. When engaged, the reference line of the survey instrument is disposed in a predetermined angular relation with respect to the barrel. The barrel has means provided on the exterior thereof for receiving a visual sighting element thereon, the sighting element being in a predetermined angular relationship with respect to the reference line. At least one non-magnetic spacer element is connectable to the barrel, the spacer element being provided with an adapter having a T-shaped head thereon which is received within a corresponding T-shaped groove provided at the lower end of the instrument.

Abstract: A centralizer apparatus for guiding, within a well bore, a tool having a radially outwardly extending member thereon includes a sleeve concentrically disposed about the tool. The sleeve has a downwardly opening, substantially J-shaped groove therein sized to receive the radially outwardly extending member on the tool about which the sleeve is disposed. The J-groove has a first, closed, axially-extending slot portion and a second, axially-extending slot portion opening at the downstring end of the sleeve. The first and second axially extending slot portions of the J-groove are spaced circumferentially apart and communicate through a substantially transverse slot portion. An outer protective jacket is provided about the sleeve. A centralizer guide depends from the lower end of the jacket to contact the walls of the bore and maintain the tool centrally with respect thereto.

Abstract: A sleeve for supporting a radially inwardly extending key disposed within the interior of a drilling sub is characterized by a substantially cylindrical body member having a plurality of ribs extending either radially inwardly or radially outwardly therefrom to define a plurality of fluid conducting channels. A plurality of threads is provided on the radially outer surface of the sleeve adjacent the first axial end thereof. A radially extending notch divides the threads into a first and second set of threads. With the first and second set of threads engaged with a plurality of threads disposed on the interior of the sub, a threaded bolt is disposed in an axially extending bore provided within the sleeve, to thereby lock the sleeve in position within the sub.

Abstract: An overshot cutter includes concentric inner and outer members, the latter having a radially flexible portion thereon. A gripper for gripping a portion of a drill string is mounted on the flexible portion. The members have inclined surfaces which, when engaged, prevent radial flexing of the inner member as the overshot cutter is lowered over the drill string. When the gripper encounters an obstacle the outer member moves relative to the inner member to axially space apart the surfaces. The inner member and the gripper thereon thereby move radially outwardly to clear the obstruction. In a first embodiment, a spring imposes a biasing force on the inner member to maintain engagement between the surfaces. When an obstruction is encountered, continued downstring advancement of the outer with respect to the inner member disengages the surfaces to define the radial clearance and for shorten the spring to store energy to re-establish contact of the surfaces after the obstruction is passed.

Abstract: A mule shoe having a closed key-receiving slot defined by long and short edges therein is characterized by a cam surface thereon connecting the ends of the edges of the slot. The sum of the angular distance occupied by the slot and the angular distance through which the cam surface winds about the axis of the member is equal to at least 360.degree.. An axially directed reaction force generated by abutting contact between the cam surface and a key is converted to a torque acting to cam the mule shoe in only a predetermined angular direction.