Abstract: A typical nuclear well logging tool forms a count rate data stream including statistical noise. A robust single pass partially deconvolved smoothing filter matched to the tool response is applied to the count rate data to enhance vertical resolution while minimizing the statistical noise increase. The smoothing filter is partially deconvolved by the application of a three point deconvolution characteristic of the cusp portion of a related cusp function and a box function representative of the tool response.

Abstract: A method for enhancing the vertical resolution of a nuclear well logging tool is set forth. A detector of nuclear radiation is moved along a well borehole to produce measurement data r(z) as a function of depth in the borehole. The data r(z) and a system response function g(z) are transformed into spatial frequency domain (f) counterparts of r(z) and g(z), the counterparts being R(f) and G(f). A window W(f) in the spatial frequency domain based on the function R(f) is defined. That smoothly eliminates the high frequency noise. A new profile function P(f) is obtained by dividing the filtered R(f) by the function G(f) to deconvolve R(f). The inverse Fourier transform of P(f) yields a vertically enhanced profile p(z) in the depth domain.

Abstract: A method for measuring the linear flow velocity, radial position, direction, and the flow rate of water flowing within and behind a well borehole casing. A logging tool containing a source of essentially monoenergetic 14 MeV neutrons and at least one gamma ray detector is positioned within the well borehole opposite the zone in which water flow measurements are desired. The neutron source is turned on thereby irradiating any flowing water and other areas in the vicinity of the well borehole with high energy neutrons. After a predetermined irradiation time, the neutron source is turned off. Following a quiescent period of several milliseconds to allow thermal capture gamma radiation to decay to a negligible level, the gamma ray detector is turned on and the count rate from the N-16 induced within the flowing water is recorded as a function of time. The linear flow velocity, the Full Width Half Maximum time period, and the total count are determined directly from the resulting count rate curve.

Abstract: A system for use in cased well boreholes for measuring gamma ray spectra induced by bombardment of earth formations in the vicinity of the borehole with fast neutrons. Monoenergetic fast neutrons emitted in repetitive pulses penetrate the borehole structure and enter earth formations in the vicinity of the borehole and are moderated by elastic and inelastic scattering to thermal energy and captured by the nuclei of elements in and about the borehole. A scintillation detector optically coupled to a photomultiplier detects gamma radiation induced by the neutrons and produces electrical pulses with amplitudes representative of the energy of gamma rays. A pulse height analyzer connected to the output of the detector and photomultiplier separates the electrical pulses into a spectrum representative of the gamma ray energy spectrum.

Abstract: In an MWD system, a mandrel for connection to the drill bit is set forth which supports shallow, intermediate and deep measuring resistivity systems. By transmitting upwardly and downwardly in alternate fashion, and receiving the transmitted signal at pairs of receiver coils, transmitted signal phase shift and attenuation are measured. A method of measuring is set forth which includes making resistivity measurements close to the drill bit at increasing ranges from the borehole so that formation resistivity prior to fluid invasion is obtained. Measurements are thus provided of formation resistivity before, during and after fluid invasion. The method also accommodates formations which have a relative dip angle with respect to the well borehole.

Abstract: A system for measuring fast neutron induced gamma ray energy spectra in cased wellbores. The system includes an electronic source of monoenergetic 14 MeV fast neutrons, a high density bismuth germanate scintillation detector, a downhole pulse height analyzer and a highly accurate gain stabilizer circuit. The gain stabilization utilizes the iron (Fe) edge in the catpure gamma ray spectrum to establish system gain since iron is always present in the tool case and the wellbore casing.

Abstract: In a well logging tool forming a data stream for telemetry to the surface, an encoding system is located downhole cooperative with surface located decoding equipment. The encoder converts serial data into NRZ symbols, then duobinary code of seven levels and then into quadrature modulating signals on a complex carrier. The decoder at the well surface receives the quadrature modulated complex carrier, forms inphase and quadrature components and decodes the two components. The decoder includes circuit means removing the intersignal distortion and also intersymbol smearing. This enables very significant telemetry ratio.

Abstract: The present disclosure is directed to an apparatus which can be installed for opening and closing fluid flow production from a formation penetrated by a cased well borehole and connected therewith through perforations. The production tubing string is installed with a moveable sleeve having a closed and open position. The moveable sleeve defines a controllable pathway into the production tubing string. In conjunction with that, there is an internal receptacle formed in the production tubing string to enable landing of a sonde there at. The sonde connects firmly at the receptacle. Similarly, the moveable sleeve in the production tubing string has a receptacle it in which enables unique landing of a latching mechanism, the latching mechanism extending along the axis of the production tubing string at the urging of a motor in said sonde. The motor operates an elongate extendible member to move the sleeve from the closed to the open position and back.

Abstract: A device (30) for sensing fluid behavior, e.g. flow, in a conduit (34) such as downhole in a well, comprises a tool (36) having two or more spaced sensors (38,40) for interacting with a medium within the conduit to produce data signals. The sensor data signals may be compared to determine movement of the medium within the conduit and about the device. The device is particularly suited for determining movement of multi-phase fluid.

Abstract: The operation of hostile environment logging tools at temperatures up to 250.degree. C. stresses not only the tools, it also places severe demands upon the wireline telemetry due to the wide variations in the logging cable transmission characteristics. A robust adaptive wireline telemetry system for use in hostile environments has been developed that combines sophisticated digital communication methods with modern Digital-Signal-Processing (DSP) techniques. The downhole telemetry transmitter outputs a multilevel signal. The uphole receiver includes an adaptive transversal-filter equalizer (TFE) that is continually optimized to correct for changing signal distortion. The system operates robustly at high data rates over the temperature range of 0.degree. to 250.degree. C.

Abstract: A method and apparatus for determining the percentage of gas by volume in a well producing mixed phase fluids and flowing up the cased well. A low energy gamma ray source irradiates the flowing fluid and counts are measured by a detector crystal. A metal casing shields the surrounding formations from the gamma radiation so that the detector response is determined primarily by the mixed phase fluids flowing in the well. Calibration enables the determination of gas volume percentage for a specific diameter casing.

Abstract: A porosity measuring MWD system utilizing a source and two detectors is set forth. The source and two detectors are preferably mounted in a stabilizer fin on a drill collar. A standoff measuring device is also included. Dependent on dynamically measured standoff, output pulses from the two detectors are input to storage counters; different counters are selected for different ranges of standoff. Porosity measurements are determined from the counts for variations in standoff measurements; this provides a near/far ratio for ranges of standoff; as the standoff range varies, the counts are directed to different counters. Near/far ratios are determined and represent the apparent porosity; a corrected value of porosity is then determined for each particular range of standoff.

Abstract: A downhole tool (100) for generating pressure pulses in a drilling fluid comprising an elongate body (107, 127) and a plurality of blades (116) spaced around the body. The blades are each divided into an independent front section (116a) and rear section (116b), forming a set of front sections and a set of rear sections, at least one of the set of front sections and the set of rear sections being mounted for rotation and being angularly displaceable relative to each other between a first position in which the sections are aligned and a second position in which the rear sections obstruct fluid flow between the front sections to generate a pressure pulse. The tool includes a first set of driving blades in front of the blades (116) for generating a torque on the blade sections, the driving blades being curved in a first direction, and an escapement means (129) which is radially movable to permit stepwise rotation of the blade sections, and thus to move the blade sections between the first and second positions.

Abstract: Evaluation of thinly laminated shaly sand reservoirs has long been one of the most difficult problems of log analysis. A primary reason is that only shallow shale indicators such as a Dipmeter, other microresistivity devices, or an ultra high frequency dielectric tool, etc. accomplish resolutions compatible with the most thinly bedded shale or sand laminae. To overcome this problem a technique has been developed to reconstruct deep Induction conductivity and to compute effective porosity and water saturation consistent with the high vertical resolution tools such as the Dipmeter.To achieve greater accuracy in the evaluation of shale content and porosity, the volumes of shale are initially estimated from both a density-neutron crossplot and a high resolution shale indicator which has been integrated to the vertical resolution of the density and neutron logs.

Abstract: This disclosure is directed to a displacement amplifier for forming acoustic pulses and more particularly to one which incorporates a flexible movable lightweight diaphragm of rectangular configuration. It has upper and lower ends which are connected to opposing piston rods driven by duplicate pistons and double acting cylinders. The cylinders are located at opposite ends of the diaphragm or membrane. They are supported in an elongate tool which positions the flexible membrane in a generally rectangular window. This enables the membrane to flex as the pistons are driven, thereby enabling the flexure of the membrane to form dipole source for radially directed compression waves transmitted from the membrane in the window.

Abstract: This disclosure sets out a method for applying a temperature correction to calculations that employ measurements made with scintillation detectors. Temperature measurements are made at or near the scintillation detectors and utilized in corrections employing measurements made with the scintillation detectors to obtain quantities that are relatively independent of temperature.

Abstract: The present disclosure sets forth a portable workover rig which is formed of a base which can be adjusted through two degrees of freedom to position a rectangular framework leveled with respect to gravity to thereby support derrick sections. The base supports the derrick sections within a derrick support mechanism which is an upstanding axially hollow structure having a side door. Each section of the derrick is inserted into the side door and can be selectively raised by a hydraulic mechanism. Each derrick section is raised to receive another derrick section to extend the derrick from the bottom up to avoid climbing. A crown assembly is placed on the derrick to adjustably position appropriate sheaves for engaging load lines extending from the well head area up to the crown and back to the well head to carry out workover of a producing well. Assembly of the derrick section by section is done from the bottom to avoid climbing the derrick. Guy wires are affixed to assure a vertical derrick.

Abstract: The present system is directed to an improved dipmeter system including plural sensors on isolated pads around a sonde. An independent output is formed from each of the sensor pads, and each output is provided to its own adjustable high pass filter. The several high pass filters delete low frequency constituents in the sensor signals. Then, the signals are provided to a dipmeter computer to determine depth with greater accuracy. As a variation, the high pass filters can be selectively adjusted to provide an adjustable frequency for the filters, and one version utilizes the derivative of the dipmeter signal as a function of velocity or time.

Abstract: An improved method for determining the magnitude of the minimum principle horizontal stress within a formation is disclosed and claimed herein. In particular, the inventive method involves the use of a wireline retrievable circumferential acoustic scanning tool during an open hole microfracture test to determine the magnitude of the minimum principle horizontal stress in the formation.

Abstract: This disclosure sets forth a fluid flow line which extends at one end from a fluid source at a pressure to be measured comprised of fluids contained within a well borehole, and the fluid flow line has a "J" shaped component to trap debris and trash to prevent it from flowing the full length of the fluid flow line and contacting a pressure transducer. The flow line is further defined by the threaded connection of two structural components making up the sonde wherein the components thread together and threads are sufficiently spaced apart to form an elongate helix as part of the flow path.