Abstract: Improved radioactivity well logging by mounting a scintillator in a hole extending through a drill collar at the lower end of a drill string so that measurements can be made while drilling. Radioactive sources (when required for well logging) are mounted in cavities which open to the exterior of the drill collar. Light from the scintillator is coupled through a right-angle prism or fiber optics through an angle of about 90.degree. so that an elongated photomultiplier tube can be mounted within a housing within the drill collar with the longitudinal axis of the photomultiplier tube extending substantially parallel to the axis of the drill collar to provide maximum cross sectional area for flow of drilling fluid with the housing in the drill collar.

Abstract: Apparatus for monitoring vibration of a bottom hole assembly used to drill a well includes at least one accelerometer mounted in the bottom hole assembly to generate data in the form of electrical signals corresponding to the acceleration experienced by the assembly. The computer in the assembly is programmed to collect data from the accelerometer and compute magnitude of the assembly acceleration. Means are provided for selecting from the collected data a value which exceeds a preset level. In one form, when the collected data has a value above a preset level, an alarm signal is sent to the surface so corrective measures can be taken to prevent damage to downhole equipment.

Abstract: An arrangement for measuring the stretch of a wire line used in well drilling operations by first measuring the amount of stretch in the deadline by measuring rotation of the dead sheave which supports the deadline, and multiplying the length of the wire line by the ratio of the amount of elastic stretch in the deadline to the length of the deadline. Equipment depth in the well is determined by measuring the movement of the wire line and applying a correction for the wire line stretch. If desired, a correction can also be applied for any errors in the split block separation. The ratio of the amount of stretch in the deadline to the length of the deadline may be employed to provide measurement of the hookload on the traveling block.

Abstract: Apparatus for sending pressure pulses through drilling fluid in a drill string in a well bore includes an assembly adapted to be lowered from the surface through the drill string to a position adjacent the lower end of the drill string. The external dimension of the assembly is substantially less than that of the internal diameter of the drill string, so there is always a substantial clearance between the assembly exterior and the drill string interior to permit a substantial flow of drilling fluid down the drill string, past the assembly, through a drill bit, and into an annular space between the drill string exterior and the well bore. The assembly includes an internal bore to permit drilling fluid to flow through the assembly. Means are provided for intermittently restricting flow of drilling fluid through the assembly bore to send the pressure pulses to the surface in response to the magnitude of a downhole condition to be measured.

Abstract: A filter for use in filtering noise from cyclical signals having a data component and a noise component in which a predetermined number of the cyclical signals are averaged to produce an average signature signal. The average signature signal is updated each cycle to produce a current updated average signature signal, and the current cyclical signals and the current updated average signals are subtracted from one another to remove the noise component and produce a residual signal which contains the data component. The time frames of the current cyclical signals and the current updated average signals are adjusted to be equal so as to enable point by point subtraction.As an additional feature, the updating of the average pump signature combines a portion of the last average pump signature with a portion of the last residual signal.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well. Anchor means on the sensing means prevents it from rotating relative to the sleeve.

Abstract: Apparatus for sending pressure pulses through drilling fluid in a drill string in a well bore includes an assembly adapted to be lowered from the surface through the drill string to a position adjacent the lower end of the drill string. The external dimension of the assembly is substantially less than that of the internal diameter of the drill string, so there is always a substantial clearance between the assembly exterior and the drill string interior to permit a substantial flow of drilling fluid down the drill string, past the assembly, through a drill bit, and into an annular space between the drill string exterior and the well bore. The assembly includes an internal bore to permit drilling fluid to flow through the assembly. Means are provided for intermittently restricting flow of drilling fluid through the assembly bore to send the pressure pulses to the surface in response to the magnitude of a downhole condition to be measured.

Abstract: A method and apparatus for encoding and synchronizing and sequencing pulse encoded data in a pulse telemetry system. The time intervals between successive pulses in a pulse train are representative of the magnitude of the data parameters. Redundant pulses are included in the pulse trains at predetermined time locations with respect to the pulses so as to enhance the ability to recognize or distinguish data pulses over noise signals. Synchronization pulses are employed to enable identification of the particular data parameters even though one or more of the data pulses is obscured by noise. The sequence of the production of the pulse code signals is continuously monitored to enable the telemetering system to be activated promptly after a shutdown at the place in the train of data where it would be if the shutdown had not occurred.

Abstract: A DC current control is provided for inductive loads which achieves high energy efficiency even though the supply voltage may be subject to considerable variations.The inductive load may be a DC motor, a solenoid, or similar device. The electric power is applied directly to the inductive load through a switching means which closes the circuit to apply a charging current to the inductive load for fixed on periods of time.A discharge path is provided for the inductive load when the switching means opens the charging circuit. The discharge current is monitored, and when it decays to a selected value, the switching means is again closed for the fixed on charge time.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well. Anchor means on the sensing means prevents it from rotating relative to the sleeve.

Abstract: A monostable, solenoid-operated valve in a passage which bypasses the drilling fluid pressure drop across a drill bit at the lower end of a drill string in a well opens and closes in response to downhole conditions to create pressure pulses in the drilling fluid. The valve is urged toward a closed position by drilling fluid pumped through the drill string. A larger force is required to open the valve than to hold it open. Current supplied to the solenoid to open the valve is thereafter reduced to a value sufficient to hold the valve open. The solenoid is de-energized to close the valve.

Abstract: A monostable valve for insertion in a drill string used in forming a borehole such as an oil well. In an open position, the valve vents drilling fluid flowing in the drill string to an annulus in the borehole for return flow to the surface, thus generating a surface-detectable negative fluid-pressure pulse. A valve closure member is supported for horizontal movement to provide significant isolation from vertical accelerations occurring during drilling, and the closure member and associated valve seat are field replaceable. Primary power for valve actuation is drawn from the drilling-fluid hydraulic energy as controlled by a low-power solenoid-actuated pilot valve.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Abstract: In an apparatus for measuring equipment depth in a well, the movement of wire rope used to raise and lower the equipment is measured by proximity sensors located adjacent the wire rope and spaced along the direction of movement of the wire rope. The signals from the proximity sensors caused by the spiral windings of the wire rope are employed to determine the length and direction of movement of the wire rope. The invention may be employed to measure movement of wire rope in other applications, such as in elevators or with cages in mine shafts that are supported by wire rope.

Abstract: In response to a signal to open and close a solenoid-operated valve, which is urged closed by flow of fluid through it, a circuit supplies a large current to the solenoid to open the valve, reduces the current to hold the valve open, and interrupts the current to close the valve. The circuit provides high electrical efficiency during operation. One embodiment of the invention is particularly suitable for use in systems in which the voltage of the power source varies over a wide range.

Abstract: In an apparatus for measuring depth of equipment in a well, a carrier system is provided on a well rig for positioning sensors adjacent a spiral wound wire rope which moves the equipment upwardly or downwardly. The carrier system employs a housing having rollers that engage the wire rope at two spaced locations. The sensors are located in the housing between the rollers, and they are maintained substantially equidistant from the wire rope by the action of the rollers so that they respond to movement of the spiral windings of the wire rope. A suspension system has arms that support the housing with reference to the rig, and the effective length of the arms is adjusted to compensate for errors in measurement that would be caused by lateral movement of the wire rope along a drum that actuates the wire rope.

Abstract: The accuracy of well logging data transmitted from a downhole location to the surface of the earth is verified by generating the data at the downhole location, storing the data in a subsurface assembly in the well, transmitting signals corresponding to the data to the surface through a first transmission system while keeping the data stored in the subsurface assembly, and recording the signals transmitted to the surface through the first transmission system. Thereafter, the subsurface assembly is transferred to the surface, and signals corresponding to the stored data are transmitted through a second transmission system from the assembly to an electronic processing system. The signals transmitted through the second transmission system are then compared with the signals transmitted through the first system.