Abstract: A system for providing a fluid communication path between the surface and a downhole location in a borehole includes a capillary tubing which is secured to the outside of a production pipe string and which is run into the borehole on the pipe string. The tubing is sized to accommodate the downhole injection of treating chemicals into the producing fluid stream, primarily for corrosion control. In many instances it is desirable to make downhole pressure measurements in a producing well. A small solid slickline with an attached plunger is pumped down the chemical injection tubing into a chamber at the bottom of the tubing. The slickline substantially restricts the cross-sectional area of the injection tubing to accommodate accurate direct pressure measurements at the remote downhole location.

Abstract: A device for protecting and securing small diameter tubular members along a pipe string in a wellbore is disclosed. The protector is designed to fit about the joints of connecting pipe sections and comprises a sleeve assembly capable of being arranged and locked about a pipe joint. The sleeve assembly preferably comprises a plurality of symmetrical, most preferably semi-cylindrical, sleeve members having interfitting longitudinal end portions, preferably held by hinge pins in circular arrangement about a pipe joint. At least one longitudinal channel is formed, preferably with a pair of parallel, longitudinal ridges on the interior surface of the sleeve assembly to receive and hold therein a small diameter tubular member. The sleeve assembly is further characterized by shoulder members spaced sufficiently far apart to bracket the greater diameter pipe joint to prevent longitudinal displacement of the sleeve assembly with relation to the pipe string and joint.

Abstract: In a borehole telemetry system for acoustically transmitting data over a pipe suspended in a borehole, the level of noise in the data stream is inherently high, making the use of discrete frequencies advantageous to provide useful data. Any drift in electrical circuits which might affect or be affected by the use of precise frequencies is undesirable. A synchronous detector facilitates the removal of noise components from the data stream by comparing in a commutative filter the phase difference between a switching signal taken from the incoming data signal path, after the second stage of commutative filtering, with the data signal emerging from the last stage of filtering. The synchronous detector also compares a data signal having two stages of filtering with another data signal having six stages of filtering with the additional filtering, causing a phase shift in frequencies outside the precise frequency window, which the synchronous detector also rejects.

Abstract: In a borehole acoustic telemetry system for acoustically transmitting data over a pipe suspended in a borehole, the level of noise in the data stream is inherently high, making the use of precise frequencies advantageous to provide useful data. A first transmitter in the system operates at a precise frequency to transmit a signal over the pipe where it is received by a receive and retransmit circuit path. Components in the receive and retransmit section filter and amplify a data component of the signal and retransmit the data signal at a precise frequency. Crystal controlled oscillator clocks are operated in the system at a same frequency in the transmitter and receiver-retransmitter to insure precise frequency control of the system.

Abstract: A telemetry system for transmitting data between a downhole location in a wellbore and the surface of a well utilizing an acoustic signal which operates within naturally occurring passbands on a string of pipe have substantially fixed frequency ranges which are related to pipe length and condition.

Abstract: In a borehole telemetry system for acoustically transmitting data over a pipe suspended in a borehole, the level of noise encountered requires the use of specific frequencies to transmit data. Any drift in electrical circuits which might affect or be affected by such use of precise frequencies is undesirable. An automatic gain control (AGC) circuit is provided which obtains its feedback from a signal which has undergone some noise filtering so that the AGC circuit is controlled by a signal having a high signal-to-noise ratio. The circuit is arranged so that the wide temperature variations occurring in a downhole environment as well as component deterioration or change do not affect the frequency of the data signal or operation of the system in dealing with a precise frequency.

Abstract: Apparatus is provided for permitting a communication wireline to be suspended in a borehole along the outside of a drill stem for subsequent side entry therein and connection to a steering tool for the relaying of information from the steering tool to the surface of the borehole. The apparatus includes an apertured section of drill pipe having a self-contained sealing structure including a wireline clamp housed therein for securing and sealingly engaging the wireline therethrough and maintaining the sealed integrity of the drill stem. In this manner mud may be pumped under pressure through the drill stem to drive a drilling head while the wireline interconnects the steering tool and the borehole surface along the outside of the drill stem.

Abstract: A single shot surveying instrument which is designed to be lowered to a desired location in a borehole and to take a single picture which indicates the direction of the borehole. The instrument operates in a first mode in which a picture is taken after the passage of a preselected period of time, which period is selected to allow sufficient time for the instrument to be properly positioned in the borehole. The instrument also operates in a second mode in which a picture is taken after the lapse of the preselected period of time if there is an absence of motion by the instrument during a last portion of the preselected time period. An indicator light on the instrument provides a check for premature operation of the instrument and for operability of the motion sensing capability.

Abstract: Binary bits that are represented by pulses are identified by circuitry that integrates a signal having a sequence of such pulses for the period of each bit pulse. At the end of the integrating period, the integrator level is stored, and the integrator is discharged. Storage and discharge are synchronized with the bit pulse rate by an oscillator whose frequency is varied until the integrator level is maximized. The presence of a bona fide signal bit is indicated by a predetermined integrator level. A false signal bit generated as part of the background noise will not endure long enough to cause the integrator to reach the predetermined level of a bona fide bit.

Abstract: A sub for use in an acoustic telemetry system provides a sound path of low impedance to facilitate the transmission of acoustic signals through a string of pipe positioned in a wellbore. The sub section of pipe includes a tubular receiving member positioned in the bore of a pipe section and spaced from the interior walls thereof. Ports and flow channels are also provided to permit the passage of well fluids through the pipe section when an acoustic instrument is positioned in the tubular receiving member. A lateral shoulder is formed in the interior wall of the receiving member and is arranged to matingly receive a flat portion on the instrument. The abutment of the flat portion of the instrument and the shoulder provides a positive sound path for transmission of longitudinal sound waves from the instrument to the receiver member.

Abstract: Inclination and high side angle of a borehole is measured by a tool that may be positioned inside a drill string and lowered into the borehole. The tool includes three gravity transducers positioned in a novel array. The transducers are positioned in a case whose axis coincides with that of the borehole and are arranged with their axes angularly displaced from each other around the case axis by approximately 120 degrees and from the case axis by approximately 45 degrees. An array of fluxgate magnetic transducers may be added to the apparatus to provide combination surveying and steering capability.

Abstract: Information as to borehole inclination is provided by a pendulum in combination with an elastomeric material whose resistance varies with compression. The pendulum is arranged in a housing to compress the elastomer whenever the housing deviates from the vertical, or other predetermined attitude. The change in resistance is measured by a circuit including an ohmmeter and the pendulum and elastomer as conductive elements.

Abstract: A lock-in filter that may be used to detect an AC data signal in the presence of high level noise signals that may occur in such systems as those used for acoustical telemetry in boreholes includes a pair of parallel capacitors receptive of the data and noise signals and circuitry operating in response to signals in the capacitors for alternately switching the capacitors to receive the noise and data signals in phase with the data signal.

Abstract: A pressure measurement system particularly suited to use in boreholes uses a pressure source at the surface to supply a test fluid through a small tube to a large downhole chamber having a fluid port on its bottom side. The test fluid displaces borehole fluid from the chamber after which the pressure of the test fluid is measured at the surface, thereby indicating the pressure of the borehole fluid.

Abstract: An unknown pressure at a remote location, such as in a borehole, is sensed by passing a fluid at a constantly increasing pressure, into a pressure sensitive device at the remote location. The pressure is monitored at the measurement location until a characteristic change in the rate of pressure buildup in the pressure sensitive device occurs. Effects of fluid supply pressure on the monitoring device are minimized in relation to buildup pressure in the pressure sensitive device by placing a flow control valve between the supply pressure source and the buildup pressure monitor.

Abstract: A system for measuring the rotation of a shaft without direct mechanical connection to it uses a digital system to maintain a second shaft that connects to a cylindrical chart recorder in a constant angular position relationship with the measured shaft. Two limit switches on the recorder shaft sense the rotation of a reference point on the measured shaft beyond a range defined by the location of the limit switches. A stepper motor driven by digital power supply incrementally rotates the recorder shaft to move a reference point on the recorder shaft back into alignment with the reference point on the measured shaft. A digital counter controls the number of pulses supplied by the power supply to stop the recorder shaft in the aligned position.