Abstract: An apparatus for drilling a well which includes a drill bit (2) arranged at the end of a length of drill tubing (4), a motor (3) to rotate the drill bit and steering means to steer the drill bit, and including torque measuring means (5) to measure the torque applied to the drill bit continuously and processing means to calculate values for the mechanical specific energy (MSB) and measured depth data over time whilst drilling. The processing means includes comparison means which is configured to compare the measured data with known data to determine the nature of the formation (6) being drilled compared to known types of formation, and which processing means is configured to indicate a change from a first formation type to a second formation type, thus indicating the presence of a formation boundary, when the drill bit is adjacent to or just past the formation boundary (7).

Abstract: A drilling assembly comprises a bent housing terminating in a drill bit (18), and a top section coupled to the bent section. The top section is suspended upon coiled tubing (10). The drilling assembly includes an orienter means (2-6) capable of rotating the bent housing with respect to the top section, wherein the orienter means includes an electric motor (34) situated in the bent section. The bent housing includes sensor means (30) for monitoring downhole physical variables, the sensor means being situated in the bent section. The orienter means may be an electro-mechanical motor.

Abstract: A downhole tool 10 includes means for detecting a downhole condition, a capacitor bank, and a sparker. The technique is particularly useful for detecting casing collars. As the tool is passed along the well bore 11, it detects collars 12. On each detection, a part of the capacitor bank is discharged through the sparker. This generates an acoustic pulse which is transmitted through the ground (wave 14) to detectors 15, 16. The movement of the tool 10 is also monitored by a movement detector 20. The position of the tool 10 is correlated with the positions of the collars 12 by a computer 22 fed via interfacing circuitry 21. If desired, the pulses may be coded by strength, number, time spacing, etc.

Abstract: A measurement means for a downhole tool for determining the orientation of the axis of a downhole tool in relation to true north. It includes a gyro sensor capable of measuring angular rate, a rotation means for rotating the gyro sensor about a sensor axis, a measurement means to detect the angular rate at the gyro sensor as it is rotated to form a series of readings, and a processor capable of interpreting the signal amplitude from the series of readings and determining the points of greatest signal amplitude. The processor is also being capable of comparing the phase difference between the actual readings taken against what would be generated with the sensor pointing true north thus providing a downhole tool axis angular deviation from true north. The rotation means rotates the gyro sensor in discrete steps.

Abstract: A measurement means for a downhole tool for determining the orientation of the axis of a downhole tool in relation to true north. It includes a gyro sensor capable of measuring angular rate, a rotation means for rotating the gyro sensor about a sensor axis, a measurement means to detect the angular rate at the gyro sensor as it is rotated to form a series of readings, and a processor capable of interpreting the signal amplitude from the series of readings and determining the points of greatest signal amplitude. The processor is also being capable of comparing the phase difference between the actual readings taken against what would be generated with the sensor pointing true north thus providing a downhole tool axis angular deviation from true north. The rotation means rotates the gyro sensor in discrete steps.

Abstract: A drilling assembly comprises a bent housing terminating in a drill bit (18), and a top section coupled to the bent section. The top section is suspended upon coiled tubing (10). The drilling assembly includes an orienter means (2-6) capable of rotating the bent housing with respect to the top section, wherein the orienter means includes an electric motor (34) situated in the bent section. The bent housing includes sensor means (30) for monitoring downhole physical variables, the sensor means being situated in the bent section. The orienter means may be an electro-mechanical motor.

Abstract: A downhole tool 10 includes means for detecting a downhole condition, a capacitor bank, and a sparker. The technique is particularly useful for detecting casing collars. As the tool is passed along the well bore 11, it detects collars 12. On each detection, a part of the capacitor bank is discharged through the sparker. This generates an acoustic pulse which is transmitted through the ground (wave 14) to detectors 15, 16. The movement of the tool 10 is also monitored by a movement detector 20. The position of the tool 10 is correlated with the positions of the collars 12 by a computer 22 fed via interfacing circuitry 21. If desired, the pulses may be coded by strength, number, time spacing, etc.

Abstract: An orienter for controlling the drilling direction in a well. A main body 40, 23 is couplable to a drill string, and a nose tubing 50 is movably mounted by a universal joint in the main body. A collar 42 with a bore 43 engages in a cam-like manner with an extension 26 of the nose tubing on the drill string side of the universal joint. The collar is movable longitudinally ‘a’ to control the magnitude ‘b’ of the nose tubing, and circumferentially ‘c’ to control the azimuth ‘d’. The nose tubing is aligned on both sides of the universal joint and the bore of the collar is angled relative to the main axis of the main body. The collar may be hydraulically or electrically controlled.

Abstract: Detector circuitry for detecting magnetic field disturbances resulting from the movement of equipment through a pipe of magnetic material, the detector circuitry comprising a difference circuit fed with the outputs of two longitudinally spaced sensor means via respective DC blocking means, a saturating difference amplifier feeding an integrator and fed with the outputs of the difference circuit and the integrator, and indicating means fed from the integrator. The detector circuitry may also including level setting means and a comparator fed with the outputs of the integrator and the level setting means and feeding the indicating means. A second comparator may be connected in parallel with the first comparator and fed with the inverse of the output of the level setting means and the output of the integrator.

Abstract: A bottom hole assembly for drilling a well, comprising a non-magnetic tubing, an orienter, a motor, a bit fed with drilling fluid which passes through the non-magnetic tubing, and a sensor package contained within the non-magnetic tubing, characterized by a drilling fluid flow tube passing through the non-magnetic tubing adjacent to the sensor package, and means for determining the relative position measurement between the non-magnetic tubing and the motor.

Abstract: Detector circuitry for detecting magnetic field disturbances resulting from the movement of equipment through a pipe of magnetic material, the detector circuitry comprising a difference circuit fed with the outputs of two longitudinally spaced sensor means via respective DC blocking means, a saturating difference amplifier feeding an integrator and fed with the outputs of the difference circuit and the integrator, and indicating means fed from the integrator. The detector circuitry may also including level setting means and a comparator fed with the outputs of the integrator and the level setting means and feeding the indicating means. A second comparator may be connected in parallel with the first comparator and fed with the inverse of the output of the level setting means and the output of the integrator.

Abstract: A detector for detecting magnetic field disturbances resulting from the movement of equipment 11 through a pipe 10 of magnetic material. A pair of linear ferrite magnetic elements 22A, 23A are positioned end to end and aligned with the axis of the pipe, and a Hall effect device 21A is positioned between the magnetic elements. The ferrite rods concentrate magnetic field changes due to the equipment 11 through the Hall effect device. Two pairs of elements 22A-23A and 22B-23B are spaced around the pipe, and a second set of pairs of elements 25B-27B, 26B is spaced along the pipe. The detector can be attached to an existing pipe, or mounted in an instrument package which passes through the pipe.

Abstract: A gauge carrier comprises a main body capable of incorporation into a suitable drill string, and a separate instrument housing including a gauge, the instrument housing being securable to the main body. The main body includes a handling region suitable for being handled by rig tongs, such that the instrument housing may be attached substantially along that handling region subsequently to its being handled. The handling region is located substantially centrally along the length of the main body. The main body includes at least one protective region having a larger cross section than the majority of the main body.

Abstract: A bottom hole assembly for drilling a well, comprising a non-magnetic tubing, an orienter, a motor, a bit fed with drilling fluid which passes through the non-magnetic tubing, and a sensor package contained within the non-magnetic tubing, characterized by a drilling fluid flow tube passing through the non-magnetic tubing adjacent to the sensor package, and means for determining the relative position measurement between the non-magnetic tubing and the motor.

Abstract: An orienter for controlling the drilling direction in a well. A main body 40, 23 is couplable to a drill string, and a nose tubing 50 is movably mounted by a universal joint in the main body. A collar 42 with a bore 43 engages in a cam-like manner with an extension 26 of the nose tubing on the drill string side of the universal joint. The collar is movable longitudinally ‘a’ to control the magnitude ‘b’ of the nose tubing, and circumferentially ‘c’ to control the azimuth ‘d’. The nose tubing is aligned on both sides of the universal joint and the bore of the collar is angled relative to the main axis of the main body. The collar may be hydraulically or electrically controlled.

Abstract: A separation method and apparatus for separating components used in downhole well development activity, whilst in position down the well. Method and apparatus are characterized in that they do not make use of external mechanical forces, or internal fluid pressure, applied through the development apparatus to render the components in a separable state. The release is achieved through the use of a fusible metal element.

Abstract: The present invention provides separation method and apparatus for separating components used in downhole well development activity, whilst in position down the well. Method and apparatus are characterized in that they do not make use of external mechanical forces, or internal fluid pressure, applied through the development apparatus to render the components in a separable state. The release is achieved through the use of a fusible metal element.

Abstract: A detonation system 10 particularly suitable for use in subterranean environments, for example in oil exploration and production, uses a detonating device 2 containing explosive material 3. The explosive material 3 is detonated by a pulse of laser light of a pre-determined frequency and power. The laser pulse is sent down a fiber optic line 5 from a laser 6 through an optical splitter 4 which is designed to reflect all frequencies apart from the above mentioned pre-determined frequency. To test the integrity of the fiber optic line a test signal from a second laser 11 is sent down the optical fiber line. The test signal has a different frequency and much lower power and is therefore reflected back along the fiber optic line by the optical splitter where it can be detected. This test signal allows testing while considerably reducing the chances of accidental damage.

Abstract: A perforating gun having no firing head and no primary explosives is attached to a tubing string and the tubing string is run into a borehole. A new pump apparatus, having a firing head, is run into the tubing string until the pump firing head is adjacent the perforating gun. The firing head in the pump apparatus detonates, firing the perforating gun. If the firing head fails to detonate, one need only remove the pump apparatus from the tubing string in order to gain access to the firing head, for repair and replacement thereof. One need not remove the tubing string to gain access to the firing head.

Abstract: A perforating gun having no firing head and no primary explosives is attached to a tubing string and the tubing string is run into a borehole. A new pump apparatus, having a firing head, is run into the tubing string until the pump firing head is adjacent the perforating gun. The firing head in the pump apparatus detonates, firing the perforating gun. If the firing head fails to detonate, one need only remove the pump apparatus from the tubing string in order to gain access to the firing head, for repair and replacement thereof. One need not remove the tubing string to gain access to the firing head.