Abstract: A method and apparatus for sonic logging using a measuring while drilling telemetry system as the sonic source is provided. Transducers are provided for receiving acoustic energy from the formation surrounding the borehole. The transducers produce a signal which is processed and telemetered to the surface using the measuring while drilling system.

Abstract: A measuring while drilling assembly utilizes two transmission channels connected in cascade in order to transmit a signal of a sensed downhole condition from a location near a downhole drill bit to a surface receiver. A first transmission channel has its downhole end connected to a first signal generator and its uphole end connected to a second signal generator. The second signal generator includes a pulser. A second transmission channel has its downhole end connected to the pulser and its uphole end connected to a pressure transducer at the surface of the earth.

Abstract: In conducting measurement operations in drill holes useful downhole information is obtained by selectively filtering data signals carrying the information from mixed signals. The mixed signals result from a mixture of the data signals and interfering signals. The data signals are arranged in a coded sequence of individual signals having a characteristic shape. Control signals representing the characteristic shape are produced. The mixed signals, which are received on the surface from a downhole location, and the control signals are converted to resultant signals that represent the data signals, wherein the effect of interfering signals is diminished.

Abstract: This invention deals with a telemetering system in logging while drilling which utilizes pressure pulses in the drilling fluid circulation system. More specifically this invention deals with generation of pressure pulses in the "regime of hydraulic shock waves" as distinct from the "regime of slow variation of pressure." Both regimes have been defined in the disclosure. A means has been provided for generating hydraulic shock waves by rapidly changing the rate of flow of the circulation fluid by means of a downhole valve. The downhole information controls the actuation of the valve which generates a succession of wavelets each of which comprises two distinguishable pulses of opposite polarity. The signal received at the surface is processed by a digital filter system in order to improve the signal to noise ratio.

Abstract: Methods and apparatus for telemetering information between spaced locations in a well drilling system including a borehole filled with drilling fluid, including transmitting at a first location, which may be at the earth's surface, a sequence of pressure pulses, and detecting at a second location, which may be at downhole equipment located in the drill string adjacent the drill bit, the pressure pulses.

Abstract: An apparatus for transmitting data to the surface of the earth in a borehole having a tubular drill string for circulating drilling fluid between the surface of the earth and downhole including a signal generator for providing electrical signals indicating a measured downhole condition, a valve within the apparatus moveable between a closed and an open condition for controlling, at least in part, the flow of drilling fluid, the valve being moved from closed toward open condition by the application of a first force, such as of a solenoid, and sequentially by a second force, such as a hydraulic fluid pressure differential across a piston to rapidly move the valve to the open condition, thereby creating a negative pressure pulse in the drilling fluid which pressure pulse is receivable at the earth's surface.

Abstract: Disclosed are improvements pertaining to measurement while drilling apparatus, methods, and systems, including: generation of mud pulse pressure variations in a regime of hydraulic shock waves; transmission of information carrying signals via mud pressure variations which include various interfering signals generally termed "noise" and employing special techniques involving digital filters for accomplishing reception of said information carrying signals; providing hydraulic means to automatically effect periodic closing of the valve means that produces the information carrying signals; providing electrical means to inhibit valve means operation in case of electrical failure in downhole apparatus; providing means which serve to greatly increase the number of satisfactory actuations of said valve means attainable without downhole battery recharge or replacement; providing unique pulse time codes which permit substantial increase in rate of information transmission and the accuracy and precision of such transmis

Abstract: A measurement while drilling apparatus for transmitting information carrying signals by fluid pressure changes in a borehole fluid circulation system having a flow restriction causing a high pressure zone and a low pressure zone, the apparatus having a passageway interconnecting the zones and a solenoid actuated valve interposed in the passageway, a sensor for sensing the magnitude of downhole measurements and for generating a succession of electric voltage changes indicative of the magnitude, a capacitor and a source of electric current for charging the capacitor, a circuit responsive to the sensor electric voltage changes for initiating successive discharges of the capacitor, which discharges are applied to the valve solenoid to produce successive openings and closings of the passageway thereby generating pressure changes in the borehole fluid circulation system.

Abstract: Apparatus and methods of making measurements in a borehole while drilling by using a fluid circulation system having interfering pressure variations including the steps of measuring selected parameters at various depths in the borehole and generating in pressure changes indicative of the values of the measured parameters, producing signals representing a superposition of the generated pressure changes and the interfering pressure variations and utilizing the recurrence of the interfering pressure variations for deriving from the first signals resultant signals representing substantially the information carrying pressure changes.

Abstract: A system for use in providing measurements from within a borehole to the earth's surface during drilling operations in which a drill pipe extends from the earth's surface having a drilling means, such as a drill bit, at the lower end and a fluid circulation system forming a column of drilling fluid within the drill string, a direct radiator telemetering system including a housing positioned within the drill string providing for the flow of drilling fluid therepast, the housing being in the form of a tubular member having within it an electrically driven pressure pulse radiating means responsive to electrical signals representing the magnitude of a downhole parameter for producing a sequence of pressure pulses indicative of the magnitude, the tubular housing being of a relatively long length being of approximately a substantial fraction of the equivalent wavelength of the pulses produced by the pulse producing means, and instruments at the earth's surface for maintaining superatmospheric mud pressure in the to

Abstract: Apparatus for transporting measuring and/or logging equipment in a borehole filled with drilling fluid, the apparatus being in the form of a transporter body of normal diameter less than that of the borehole characterized by apparatus for effectively advancing the transporter in a borehole and for reducing the possibility that the transporter will become stuck in a borehole.

Abstract: This invention is concerned with downhole measurements while drilling a borehole in the earth with a drill bit at the lower end of the drill string and transmitting such measurements to the surface. The drilling fluid is forced through a fluid passage which includes a drill string, a bit at the lower end thereof and the annulus surrounding the drill string. There is a restriction in the passage causing a pressure drop creating a high pressure zone and a low pressure zone within said passage, and a drilling fluid bypass comprising a bypass valve provides fluid communication between the high pressure zone and the low pressure zone. By means of a downhole sensor and associated equipment a plurality of pulse or electrical voltage change signals representing downhole information is produced. Each of these signals is arranged to generate several electrical voltage changes.

Abstract: A system for providing measurements while drilling a well in which a drill string, made up of standard lengths of drill pipes, some of which may be drill collars, extends from the earth's surface in a borehole, drilling fluid being circulated in the drill string and borehole, the measurements being transmitted to the earth by a pulser which produces, in response to electrical signals from a measuring instrument, pressure pulses in the drilling fluid which are detected and decoded at the earth's surface, the pulser being mounted in a special pulser sub which is of short length and enlarged internal diameter compared to a standard drill pipe and which is threadably secured at each end in the drill string, and an elongated housing supported by the pulser sub, the housing having an outside diameter less than the internal diameter of the drill pipe and being slidably received in drill pipe adjacent the special sub, the elongated housing containing instrumentation or batteries, or both which are connected to the pu

Abstract: A DC power source for use in a wide range of variable temperatures employing a battery having the characteristic that it is substantially dormant at normal ambient temperatures and operable only at temperatures substantially above normal ambient temperatures, including a heat retaining housing in which the battery is positioned and a controllable heat source within the housing to maintain the temperature of the battery within a preselected elevated range corresponding to the effective operating temperature characteristics of the battery.

Abstract: A method and apparatus for continuously logging while drilling a well bore with a rotary drilling rig comprising a drill string, a jet type drill bit, and mud pump means for circulating fluid under pressure. The apparatus generally includes means for sensing one or more downhole parameters near the drill bit, means for generating a sequence of electrical pulses representative of said parameter, and means for generating negative mud pressure pulses in the drilling fluid ("drilling mud") within the drill string in response to said electrical pulses. Receiving means at the earth's surface detect the negative mud pressure pulses and utilize the sequence of these pulses to produce signals representative of said parameter. The receiving means employ means to substantially eliminate the effects of the pressure pulsations generated by the mud pump and to extract the negative mud pressure pulses the sequence of which represent the downhole parameter.

Abstract: A resilient conductor having an outer flexible insulating coating and an inner flexible conducting core is employed in a drill string to maintain an electric circuit between a subsurface and surface location. The conductor is inserted in the drill string in a generally free-hanging, random fashion to store excess length of conductor which is utilized as the drill string is lengthened. The stored conductor can be maintained in the drill string in a generally untangled state due to its kink-resistant mechanical and physical properties. Moreover, the frictional drag of the flowing drilling fluid tends to straighten and disentangle the conductor.

Abstract: Logging while drilling apparatus included in a rotatable drilling string of drill pipe disposed in a well bore. Apparatus generally includes a combination communication system comprising two communication channels coacting in cascade or tandem fashion with a first lower communication channel having very low attenuation characteristics but being relatively inconvenient to connect or disconnect and with a second upper communication channel having greater attenuation characteristics but being very convenient to connect or disconnect when adding drill pipe as drilling continues. Electrical power for the entire combination in the well bore is provided from a location remote from the bottom of the well. Also discloses related methods of logging while drilling.

Abstract: Apparatus and method for detecting the presence of nitrogen and oxygen-containing explosives within a container by irradiating the container with thermal and high energy neutrons, and then measuring the quantity of thermal energy neutrons passing through the container and the quantity of radioactive nitrogen 16 generated within the container. The measurements of neutron absorption and nitrogen 16 are correlated to provide an output signal indicative of whether the material within the container is an explosive.

Abstract: This describes a method for improved data signaling equipment for use with well-drilling tools for rapidly sending measurements made down the hole in the wellbore to the surface without the need of an electric cable. A special well tool is connected into a drill string having a drill bit coupled thereto for drilling a borehole. During normal drilling operations, the data-sending equipment is not in operation, and the main body of circulating or drilling fluid is passed through a main valve in the downhole tool and bypasses a pressure-changing unit. A sensing unit is incorporated in the downhole tool and measures downhole parameters. When it is desired to send these data to the surface, the main circulation of drilling fluid is stopped and the bypass valve closed. Then, a small amount of fluid is supplied to the "closed" drill string from a substantially constant-pressure source.