Abstract: The present invention is directed to a coin counter for use with a coin handling apparatus for receiving coins at a first location and discharging the coins at a second location through a coin discharge slot remote from the first location. The coin handling apparatus includes a coin transport channel extending from the first location to the second location and dimensioned so that coins can move therein in a single, edge-to-edge file. The channel terminates at the coin discharge slot at the second location. A sensor is located proximate to the coin discharge slot for sensing the passage of each coin as it leaves the channel through the coin discharge slot. A counter means is coupled with the sensor for counting the total number of coins passing through the coin discharge slot.

Abstract: A method and apparatus for perforating a formation surrounding a wellbore and initiating and propagating a fracture in that formation to stimulate hydrocarbon production from the wellbore. The technique uses a perforation and propellant loading device which perforates and fractures in a single operation to greatly increase the efficiency over current perforation techniques. Efficiency is increased by a number of factors including firing the perforating shaped charge through a gas zone, reducing the overall perforation damage to the formation, increasing operation speed, and increasing pressure in the area of the borehole surrounding the production zone before perforation and propagation are initiated. In accordance with the invention, the timing of the propellant ignition and charge detonation are critical to achieve the desired results.

Abstract: The invention relates to a logging method and apparatus using passive azimuthal electrodes. The apparatus includes an array of azimuthal electrodes (M'az.sub.i) that are circumferentially spaced apart from one another on a body together with two annular guard electrodes (A2) disposed on either side of the array of azimuthal electrodes (M'az.sub.i). The guard electrodes (A2) emit currents. Two annular monitor electrodes (M3, M4) are associated with the annular guard electrodes (A2). The potential difference (.DELTA.Vaz.sub.i) between the interconnected monitor electrodes (M3, M4) and each of the azimuthal electrodes (M'az.sub.i) are detected. In response to the detected potential differences, output signals (R'az.sub.i) representative of the resistivity of the formations in a plurality of directions around the axis of the borehole are generated.

Abstract: An apparatus for reducing or eliminating the effects of a quadrupole component of an acoustic signal received from a transversely mounted acoustic source in a drill collar of a logging while drilling tool. The apparatus includes a drill collar for supporting a drill bit, a transversely mounted transmitter situated in a first horizontal plane in the drill collar which transmits acoustic energy into an earth formation. The drill collar also houses at least one receiver mounted in a second horizontal plane in the drill collar at an angular displacement from the transmitter such that the effects of a quadrupole component of the acoustic energy detected by the receiver are rendered insignificant.

Abstract: Apparatus for obtaining horizontal and/or vertical permeability measurements through a probe having an elongate aperture. The invention uses the elongate aperture in the probe to orient fluid flow in an earth formation horizontally or vertically. The elongate aperture is approximated through the use of a single elongate opening or through the use of a group of aligned openings of varying shapes. Measurements can be taken at different orientations by including additional probe openings along more than one axis.

Abstract: A method and apparatus for spatially filtering a signal set to enhance interface echoes representing a borehole configuration. The spatial filtering technique provides information regarding the various interfaces formed between materials in the borehole environment, as well as thicknesses of the various materials present in the borehole. Further, the presence of channels formed during the cementing procedure are detected.

Abstract: A borehole tool has a source probe in fluid contact with the borehole wall, a fluid flow line for bringing fluids to and from the source probe, two injection fluid chambers containing clean oil and clean water and in fluid contact with the fluid flow line, at least one sample chamber for receiving fluid from the formation, valves for selectively routing the formation fluids and the clean oil and water through the fluid flow line, at least one pressure controller for controlling whether fluid is to be injected or withdrawn from the formation via the source probe, and a pressure gauge for measuring the pressure seen at the source probe. Permeability measurements are made by sequentially injecting one clean fluid into the formation, followed by a cleaning of the line with the other fluid which was not injected, followed by the injection of the other fluid into the formation. The order in which the oil and water are injected is based on the type of mud used for drilling.

Abstract: Fluid flow measurements are made in situ using a repeat formation tester with a modified probe aperture, or on rock samples using a mini-permeameter with a modified probe aperture. The modified probe aperture has an elongate cross-section, such as elliptic or rectangular. A first flow measurement is made with the longer dimension of the probe aperture in a first orientation (e.g., horizontal or vertical) with respect to the formation bedding planes. A second flow measurement is made with the probe aperture orthogonal to the first orientation, or with a probe aperture of non-elongate (e.g., circular) cross-section. Simultaneous equations relating values of known and measured quantities are solved to obtain estimates of local horizontal and/or vertical formation permeability.

Abstract: Methods and apparatus are described for simultaneously acquiring time-domain (e.g., compressional) and frequency-domain (e.g., monopole Stoneley and/or dipole shear) borehole logs which are separated by frequency filtering. Monopole (Stoneley) data and dipole (shear) data are acquired simultaneously using discrete-frequency sonic emission, preferably at distinct frequencies to avoid cross-mode interference. A preferred embodiment combines discrete-frequency dipole sonic emission at low frequency (up to 5 kHz) to log formation shear wave, high frequency (5 to 30 kHz) time-domain monopole emission with first-motion detection to log formation compressional wave, and discrete-frequency monopole emission at low frequency (below 5 kHz) to log borehole Stoneley wave. The measurements of compressional, shear and Stoneley can be transmitted uphole using a small telemetry bandwidth.

Abstract: Methods for determining hydraulic properties of a formation surrounding a borehole are disclosed. The methods use a borehole tool preferably having a first probe for injecting fluid into a formation or obtaining fluid from the formation, a second probe vertically displaced relative to the first probe, and a third probe azimuthally displaced relative to the first probe. The method generally comprises: varying the pressure at the first probe of the borehole tool; measuring pressures at the second and third probes resulting from the varying of pressure at the first probe; and utilizing the pressures measured at the second and third probes to determine values over time of a function related to the hydraulic properties of the formation. This function is a function of the geometry and rock and fluid properties of the formation but is independent of the manner in which the pressure is varied at the first probe.

Abstract: Method for determining at least one characteristic of a casing cemented in a borehole, such as cement bond and casing thickness, from a reflected acoustic signal S(t) obtained by directing an acoustic pulse at a substantially normal incidence towards a radial sector of the wall of the casing, the pulse stimulating thickness resonance within the walls of the casing. The method according to the invention comprises the steps of: determining a first time window corresponding to a first portion of signal S(t) including the initial reflection from the casing and subsequent acoustic returns due to resonance, determining a second time window corresponding to a second portion of signal S(t) mainly including the initial reflection from the casing, and determining the casing characteristic from information related to resonance contained in the first time window while normalizing the information by information contained within the second time window.

Abstract: A technique is disclosed for determining properties of an anisotropic elastic medium, such as earth formations. Acoustic waves are established in the medium. At several spaced locations in the medium, there are measured at least two orthogonal components of acoustic waves which have propagated through the medium. For positions corresponding to a plurality of adjacent ones of the spaced locations, there are computed model composite waves which would result from the superposition of a plurality of model acoustic waves, each having selected model parameters. The model acoustic waves include a plurality of model acoustic shear waves and the model parameters include model velocities and model polarizations for each of the model acoustic shear waves. An error value is determined, the error value depending on the differences, at each of the plurality of adjacent ones of the locations, between measured wave components and the model composite wave. The model parameters are then modified.

Abstract: A system and method for data processing in which data processing tasks are arranged as separate processes, each of which can be executed by a dedicated central processing unit or by one or more shared processing units. All communication between processes takes place via streams of data items. Each stream receives data items from a single source, for example from an input to the processing system or from one of the processes. Every data item appended to a stream is associated with a unique index value--even if physical memory locations are re-used, index values never are. A process can request a data item in terms of the stream where it is stored and the index value associated with it. Within constraints imposed by physical storage capacity, any index value can be included in a request. If the data item is not yet available, execution of the process is suspended until the data item becomes available.

Abstract: A sonde for acquiring seismic signals in a borehole, the sonde comprising: a detector module (30) enclosing at least one seismic sensor (G); an elongate body (21) having a lateral cavity (22) suitable for receiving the detector module (30); a resislient suspension (40, 50) connecting said module to said body; and an anchor member (12, 13) disposed on the opposite side of said body to the side in which said cavity is disposed. The sonde is characterized by the fact that the resilient suspension exerts a force on said module suitable for displacing it out from the cavity and for pressing it against the wall of the borehole so as to couple it to said wall, together with means (41, 43, 51, 53, 60) which are provided to retract the module into said cavity against the force exerted by the resilient suspension.

Abstract: Methods are provided which utilize a sonic tool for quantitatively determining parameters of a velocity profile of an altered zone in a rock formation traversed by a borehole. Synthetic amplitude information for the formation is generated by a computer model, by providing the computer with a proposed velocity profile for the formation, including values for parameters such as the radius of the altered zone and the acoustic velocities in the altered zone. The synthetic amplitude information is then compared with amplitude information (e.g. peak or total energy) of a compressional headwave as measured by the array sonic tool. If the comparison provides differences exceeding predetermined thresholds, the values for the parameters of the model are adjusted according to a least squares fit procedure until suitable values are found. The suitable values are then taken as the parameter values.

Abstract: An apparatus is disclosed for perforating, testing, and repairing casing in an earth borehole. A device is moveable through the casing. The device can be mounted on a wireline, on tubing, or on both. A perforator is mounted in the device for producing a perforation in the casing. The device will also generally include components for hydraulic testing/sampling from the formations behind the casing. A plugger is mounted in the device for plugging the perforation with a solid plug or a non-solid sealant.

Abstract: Methods for characterizing acoustic transducers and using a characterized acoustic transducer for measuring cement impedance of a cased well are disclosed. The method for characterizing the acoustic transducer generally comprises: arranging the acoustic transducer a predetermined distance from a calibration target of known thickness; transmitting a pulse from the acoustic transducer through a known medium and toward the calibration target and measuring a return signal received therefrom; and fitting, via minimization, a return signal calculation generated by a model of the return signal which has a limited number of parameters, to the received return signal to determine a value for at least one of the parameters and thereby characterize the transducer. The preferred parameters for characterization are the transducer radius and stand-off, such that the transducer may be characterized as having an effective stand-off and an effective radius.

Abstract: Methods are provided for determining the axial and radial slowness of a formation traversed by a borehole via utilization of sonic data obtained from a sonic borehole tool having a plurality of detectors. The methods utilize first arrival time information, ray tracing techniques, and backprojection techniques. The differences between the actually measured first arrival times and the theoretical first arrival times as calculated by ray tracing through an initial slowness model of the formation, are backprojected along the theoretical ray paths of first arrival in order to modify the initial slowness model of a formation. The methods utilized are preferably iterative, such that the modified slowness model is then utilized for additional ray tracing and backprojection. Secondary arrivals may also be utilized to refine slowness determinations made from first arrival information.

Abstract: The present invention offers methods and apparatus for sonic borehole logging of formation shear using discrete frequency measurements. A multipole source transducer emits sonic energy at a location in a borehole of at least one discrete frequency which induces propagation of multipole sonic waves in the borehole; sonic energy of the multipole sonic waves is detected at multiple receiver locations in the borehole by multipole receivers to produce a received sonic signal for each location, the multiple receiver locations being spaced apart from one another and from the source transducer location. For each receiver location, the complex values of the received sonic signal are detected relative to a predetermined phase reference. The detected complex values of the received sonic signal may be processed to determine multipole sonic wave velocity and shear attenuation at discrete frequencies and to calculate velocity and attenuation as a function of frequency.

Abstract: A method of identifying lithology of a formation traversed by a borehole from which sonic data is acquired is disclosed. The sonic data acquired comprises a data set of m waveforms, each of the waveforms including a formation wave component digitized into n samples. The formation wave component comprises direct wave components and typically reflected wave components, converted wave components, and noise. A preferred lithology identification method comprising the steps of characterizing the n samples of each formation wave component as a vector, obtaining a first eigenvector based on the formation wave component vectors, selecting a formation wave component vector, calculating a projection of the selected wave component vector on the first eigenvector, and identifying the lithology of the formation through which the selected wave component passed based on the projection of the selected wave component vector on the first eigenvector.