Abstract: Methods are disclosed herein for determining the point of entry of water cut into a cased well borehole. A well logging sonde is moved past a perforated interval in a cased well borehole. The borehole environment is irradiated with 14 MeV neutrons from a neutron source and measurement of movement of oxygen activated borehole fluid past two gamma ray detectors spaced from the neutron source is combined with the speed of movement of the logging sonde to derive a signal representative of the entry location and flow rate of the oxygen activated fluid. At least one borehole fluid sample is taken in the interval between the point of neutron irradiation and the detection of oxygen activation gamma rays to resolve any ambiguity in the total flow rate of borehole fluid in the interval.

Abstract: A method and apparatus (108) are disclosed for spectral gamma ray logging of a well borehole (106) to determine elemental concentrations of radioactive materials in subsurface earth formations (100) and in the borehole region. Anomalous radioactive deposition in the borehole region is identified and the effect thereof compensated for in the elemental concentration determinations.

Abstract: For use in a perforating gun assembly typically lowered on an electric wireline or on tubing into a wellbore exposed to high pressure and high temperature, an apparatus is set forth which includes an elongate cylindrical housing cooperative with detonating cord. It has a side port or window to enable the detonating cord to be folded slightly into it. The housing includes a cavity for receiving required explosives and connection with an ignitor. This arrangement enables the housing to connect with the detonating cord and overcome high pressure or high temperature difficulties. This will accommodate detonating cords of different sizes and shapes and with differing types of covering materials.

Abstract: A system and method for automatically pointing a microwave antenna at a desired satellite in geosynchronous earth orbit from a remote location, such as encountered in a well logging, is disclosed. The system uses a truck borne, gimbal mounted antenna and a computer arranged to automatically control and drive servo motors connected to the gimbal mounts of the antenna. Accurate pointing with minimal human intervention is achieved.

Abstract: For use in drill pipe conveyed logging systems wherein the logging apparatus is enclosed in a housing affixed to the lower end of a drill pipe string, a system is disclosed utilizing a wet connector and overshot. The wet connector includes a centralized upstanding mechanical connector means having a J-slot cooperative with pins inserted thereinto. The J-slot is adjacent to a sleeve which telescopes over an enclosed and protected upwardly facing electrical connector means. On the overshot, the solid body thereof includes a lower appended skirt having inwardly protruding pins which engage the J-slots to achieve a separate mechanical connection. There is internally of the overshot a spring mounted telescoping and movable electrical connector including a cooperative socket engaging the plug of the wet connector. The electrical connection is kept separate from the mechanical connection so that the entire load of operation is carried separately without interfering with operation of the electrical connectors.

Abstract: Statistical variations in simultaneous shallow and deep investigation nuclear borehole logs are reduced using digital moving average data processing while maintaining responsiveness to formation changes, by transitioning through a combination of long and short filtered data as a function of the statistical variation of the deep log data differences of the long and short derived averages. Borehole rugosity is also indicated as a function of the difference between the shallow and the deep log indexes of the differences between their respective narrow and wide derived averages.

Abstract: Uranium ore zones are quantitatively evaluated using the relative photoelectric absorption of naturally occurring gamma rays in two energy bands. One band experiences significant photoelectric absorption from uranium; the other does not. The ratio of the resultant measurements provides a quantitative indication of the uranium concentration.

Abstract: The uranium and thorium count rates from a fluid bearing shaly sand reservoir are normalized to the formation porosity and then, by a direct correlation, used to obtain the clay counter-ion concentration of the formation.

Abstract: In a tubing conveyed perforating gun assembly, a detonator is discharged by a weight bar dropped into the tubing string, subject to unintended sticking. The disclosed safety anchor includes a rope socket enabling the safety anchor to be lowered into the tubing string. The safety anchor has an elongate body connected below the rope socket by a shear pin. The body has a mandrel and sleeve construction cooperatively connected with a bottom located grapple cage around collet fingers enabling a fishing neck on the weight bar to be grasped and firmly held. A slip radially expands to lock the safety anchor in the tubing string, enabling the weight bar to be held against falling for safe retrieval.

Abstract: A method of registering perforating guns in a tubing conveyed perforating assembly as set forth. On a tubing string, a TCP assembly is lowered in a cased well. In the tubing string, a logging cable supported radioactive logging tool is then moved along the well to controllably locate the formation of interest. After the depth of this formation is known, the tubing string is moved to reposition the TCP assembly in registry with the formation of interest. The logging tool is retrieved only partially and is then lowered to operative contact with the TCP assembly to provide a signal path for operation of a firing mechanism to fire the shaped charges to form perforations into the formation.

Abstract: Compensation of photoelectric absorption measurements for borehole effects during nuclear logging of downhole earth formations is accomplished by detecting low energy gamma radiations entering two detectors in the logging tool along paths having substantially constant formation components but varying borehole components.

Abstract: In a tubing conveyed perforating gun assembly having shaped charges to perforate a well, an improved pressure sequence shaped charge detonator is included. The preferred form of device is appended to the bottom of the assembly to function as a backup detonator. First and second piston and cylinder assemblies in an elongate body provide pressure initiated arming and subsequent pressure initiated firing pin movement to achieve primer cord detonation for perforation of the well. The pressure sequence is controllable, selectively to a specified pressure to arm and thereafter to fire.

Abstract: For use in a tubing conveyed perforating gun assembly, the assembly including N shaped charges, a safety device is disclosed. In the preferred and illustrated embodiment, the safety device includes an N+1 shaped charge positioned to destroy a transmitter means forming a signal transmitted up the well. The transmitter means is secured within a cylindrical housing closed by a sacrificial cover, all assembled to the TCP gun assembly.

Abstract: Statistical variations in nuclear borehole logs are reduced using digital moving average data processing while maintaining responsiveness to formation changes, by transitioning through a combination of long and short filtered data as a function of the statistical variation of the differences of the long and short derived averages.

Abstract: In tubing conveyed perforating well completion operations, shaped charge detonation is achieved by dropping a detonating bar in the tubing string. Velocity of the detonating bar is controlled by placing a column of standing fluid above the tubing conveyed perforating assembly. This apparatus and method isolate a column of standing fluid. Moreover, invasion by a well fluid is prevented to assure that the retardation characteristics of the standing fluid are not changed by invading well fluids. The apparatus includes a tubing string pressure isolation piston assembly slidable within a sleeve and a frangible closure disk broken by the detonating bar; the isolation tool further includes check valve means controllably venting fluid pressure across the valve means.

Abstract: For use in a pulsed control system in a logging tool cooperative with a neutron generator, a pulsed ion source power supply is set forth in the preferred and illustrated embodiment. A string of field effect transistors (FET) connected between high voltage supply and ground is connected for switching the output voltage to form pulses of a desired amplitude and frequency. A timing circuit forms off and on control signals applied to pulse forming circuits. Pulse forming circuits form signals applied to gates of the FETs for timed control thereof, controlling the formation of a high voltage pulsed output signal applied to the neutron generator.

Abstract: For use in preparing cement to cement a well, a cement metering system is set forth. The preferred and illustrated embodiment incorporates flow meters measuring water delivered to a cement jet mixer for cement and water into a slurry. A downstream density meter is included. A second water line dilutes the slurry to adjust the density downwardly to the desired slurry density controlled by the control system. The control system includes a data formatting circuit connected to the various transducers which converts the data so that the density required for the slurry is obtained. As desired, the data can be totalled by integrating over a period of time and shown on the data display. Volume flow rate of the controlled density slurry and bulk volume of dry cement may be determined.

Abstract: For use in downhole logging tools responsive to gamma rays or x-rays, an improved scintillation device is set forth. In the preferred and illustrated embodiment, a scintillation crystal, typically sodium iodide (thallium activated), is utilized. It is an elongated, regular structure having two ends, and separate photomultiplier tubes (PMT) are attached at the separate ends. The two PMT output signals are supplied to a circuit which forms a signal adjusted or modified to compensate for loss of light energy arising during transmission through the scintillation crystal to the PMT's.

Abstract: For use in a sonde adapted to be lowered in a well bore, the present apparatus sets forth an improved nuclear event detector. The detector is sized and shaped monotonically increasing in cross section or diameter with increasing distance from the radiation source to thereby bias the detector; this bias counteracts the bias arising from geometry altering the pattern in which nuclear events impinge on the detector, thereby altering the distribution of such events.

Abstract: A well logging system for measuring the radial density distribution of earth formations in the vicinity of a well borehole is provided. The system utilizes a single position sensitive gamma ray detector capable of deriving formation bulk density using the gamma-gamma scattering technique a different radial distances from the well borehole.