Abstract: A method and apparatus for conducting in situ tests on a subsurface earth formation of interest which is traversed by a wellbore. A wireline formation testing instrument is positioned at formation depth and a sampling probe thereof is extended into fluid communication with the formation and isolated from wellbore pressure. Utilizing a hydraulically energized double-acting bi-directional piston pump and by valve controlled selection of pumping direction testing fluid such as completion fluid may be pumped into the formation through the sampling probe either from fluid reservoirs of the instrument or from the wellbore. After reversing the operating and control valving of the pump and instrument, the piston pump is utilized to extract formation fluid from the formation and pump it to sample tanks of the instrument, pump it into the wellbore or subject it to controlled pressure for real time formation testing and for formation characterization.

Abstract: In an induction logger, a method for nulling the output signal from a pair of series-coupled receiver coils by altering the magnetic flux distribution within the coils by use of one or more magnetic equalization bodies. The shape and aspect ratio of the equalization body are chosen to minimize temperature dependence of the initial permeability. Alternatively, a highly conductive equalization body may be used.

Abstract: The invention is a lid for a shaped charge which enables application of torque to the shaped charge for mounting in an expendable bar carrier borehole penetrating gun assembly. The lid comprises a plurality of flat surfaces facially parallel with the axis of a threaded stud forming part of the lid, the stud engaging mating threads in a hole in the carrier. The flat surfaces are arranged around the circumference of the lid so that a wrench or socket can be used to apply torque to the lid for mounting in the carrier. Each juncture of two contiguous ones of the flat surfaces includes a score line extending substantially perpendicular to the axis of the stud.In a preferred embodiment of the invention each juncture includes a crimp on part of the juncture on a side of the score line opposite to the stud, to retain the lid on the charge.The invention is also an apparatus for simultaneously torquing a plurality of shaped charged in a bar carrier. Each of the shaped charges comprises the charge lid of the invention.

Abstract: This invention discloses a method and apparatus for waterblocking wire-to-wire connections in a cable using an arrangement of seals. Lead-in transmission lines are slid through a multiple-aperture seal to produce a compression seal between the transmission lines and the seal and the trailing transmission line is slid through a single-aperture seal to produce another compression seal. A piece of constrictive tubing is slid over the first seal before splicing the wires in the lead-in and trailing transmission lines together. The tubing then is positioned over both seals to produce a compression seal between the tubing and the seals to form a waterblock in the area defined by the two seals containing the splice.

Abstract: A seismic cable segment is provided having a longitudinal seam for access into the seismic cable, a cable skin lock, a flotation tube for varying the buoyancy of the seismic cable, external stress members isolated from the inside of the seismic cable, and an environmentally safe gel filling the seismic cable.

Abstract: An apparatus and method for digitally processing signals received by an induction logging tool having a transmitter and a plurality of receivers. An oscillating signal is provided to the transmitter, which causes eddy currents to flow in a surrounding formation. The magnitudes of the eddy currents are proportional to the conductivity of the formation. The eddy currents in turn induce voltages in the receivers. The received voltages are digitized at a sampling rate well above the maximum frequency of interest. The digitizing window is synchronized to a cycle of the oscillating current signal. Corresponding samples obtained in each cycle are cumulatively summed over a large number of such cycles. The summed samples form a stacked signal. Stacked signals generated for corresponding receiver coils are transmitted to a computer for spectral analysis. Transmitting the stacked signals and not all the individually sampled signals, reduces the amount of data that needs to be stored or transmitted.

Abstract: This invention provides a method for examining the geometry of the disposition of a plurality of sources and receivers over an area to be surveyed with a view to optimizing the array to avoid data shadow zones and to optimize the resulting seismic image. The method depends upon studying the statistical distribution of dip polarity in dip bins along selected CMP azimuths.

Abstract: A multi-dimensional assemblage of time/velocity functions are sampled for velocity as a function of incremental time. The samples are stored in a matrix arranged in columns along the time axis and rows across the velocity axis. The count of the number of samples resident in the respective cells of each row is indexed. A desired statistical operator is applied to the count indices in the rows to provide a family of filtered histograms in time-sequential order. The filtered histograms may be edited by delimiting acceptable velocities to lie between preselected percentiles.

Abstract: A seismic source apparatus 10 includes body 12, cap 22, actuator 24, and shuttle 26. Body 12 includes a main chamber 14 that is formed therein and adapted to receive a charge of compressed air. Actuator 24 is preferably a solenoid actuated valve, capable of rapidly opening and closing in response to an electrical signal. Seismic source apparatus 10 includes a solenoid chamber orifice 38 that is positioned within a fill passage 34 to enable fluid communication between fill passage 34 and solenoid chamber 40. Solenoid chamber orifice 38 and solenoid chamber 40 are configured to provide a quick burst of high pressure air through actuator 24 when actuator 24 is opened in order to start the shuttle 26 in motion, while restricting the flow of air from main fill passage 34 and main chamber 14 into the actuator 24 so that the pressure in the main chamber 14 remains high enough to emit a suitable bubble, and so that shuttle 26 is not prevented from closing.

Abstract: A method for adaptively creating a filter for removing coherent environmental noise from a multitrace digitized seismic recording requires the presence, on the recording, of a limited sample of pure noise that is uncontaminated by desired signal. The pure noise sample is used to discover the location of the noise source and from that discovery, to extrapolate and reconstruct the characteristics of the noise envelope as it would appear on the seismic recording. The reconstructed noise envelope is used as a noise reference for input to a conventional iterative adaptive noise cancellation filter loop. For stability, the loop gain is minimized by temporally and spatially averaging the filter coefficients for each sample interval.

Abstract: The invention is an apparatus for increasing the signal amplitude of a piezoelectric acoustic transducer. A piezoelectric actuator is affixed to an arched spring which changes arched height in response to change in length of the actuator. The spring drives a rigid surface which can be directly coupled to a material which is to be acoustically energized. In a particular embodiment of the invention, the rigid surface is coupled to an hydraulic transmission. The output of the transmission is coupled to the material which is to be acoustically energized.

Abstract: Seismic data from co-located sensors of different genera are formatted into common velocity-receiver gathers and common pressure receiver gathers. A first ratio between the velocity signature amplitudes and the pressure signature amplitudes is measured within a fixed analysis window. A second ratio is measured between the pressure and velocity signatures for a weighting-zone window of limited extent. The first and second ratios are combined to form an equalization operator. The pressure and velocity signatures from within the weighting zone window are combined in the presence of the equalization operator to define a transient-free time-scale datum.

Abstract: The invention is an apparatus for rotary drilling of core samples from the wall of a wellbore. The apparatus comprises a coring bit, a motor, a bit box rotatably mounted within a housing adapted to traverse the wellbore, a plunger for extracting the core sample from the bit and discharging the core sample into a storage barrel which has a sponge liner. The sponge liner in the barrel adsorbs liquid hydrocarbons which may be expelled from the porosity in the core sample by gas exsolution.

Abstract: The invention is a method and apparatus for measuring the quality of acoustic coupling between a wellbore wall and a borehole seismic sensor system. The system includes the steps of positioning the system at a desired depth in the wellbore and activating a locking mechanism powered by a DC motor. The motor then has broadband AC applied to it to cause vibration of the system. The output of at least one seismic sensor in the system is processed in a spectrum analyzer, and the result is checked for the presence or absence of natural resonance of the system. In a particular embodiment, the system response to the broadband AC is used to generate an inverse filter operator to compensate the system response to a geophysical survey for partial acoustic coupling.

Abstract: The present invention is a method and apparatus for inserting electric wireline tools into a wellbore using an apparatus comprising pipe assembled from sections and coiled tubing having a coaxially inserted wireline. The method includes the steps of attaching a first part of a submersible electrical connector to one end of the coiled tubing and to the wireline inside the coiled tubing. A second part of the submersible connector is attached to one end of the wireline tools. A first part of a selectively operable latching mechanism is attached to the same end of the wireline tools. A second part of the latching mechanism forms part of a latching sub which is attached to one end of the pipe. The tools are attached to the pipe by engaging the first and second parts of the latching mechanism, and the tools are inserted into the wellbore to a predetermined depth by assembling the sections of the pipe. The coiled tubing is then inserted into the interior of the pipe until the submersible connector is engaged.

Abstract: This invention provides a stabilizer for a geophone which reduces the amount of movement of the geophone after deployment in a marine environment subjected to water currents or turbulence. The stabilizer consists of a bulb-shaped body with fin-shaped lobes. An axial cavity for receiving the geophone housing containing the geophone is located at one end of the stabilizer. The other end terminates in a tail designed to promote laminar flow and reduce turbulence coming off the geophone housing and stabilizer. When the geophone is deployed, the stabilizer and attached geophone housing come to rest on a stable, 3-prong base comprised of two adjacent lobes of the stabilizer and the end of the geophone housing opposite the end inserted into the stabilizer.

Abstract: The invention is a method for installing a wireline inside a coiled tubing. A first piston is attached to one end of the wireline. A pump-through head with a removable packing and a fluid inlet is attached to one end of the coiled tubing. The wireline and first piston are inserted through the pump-through head. The removable packing is reinstalled. Fluid pressure is applied by a pump to the fluid inlet. A section of wireline has been pumped into the coiled tubing. The pump is stopped. The packing is removed. A second piston for suspending the wireline from contact with the tubing is installed on the wireline. The steps are repeated at spaced apart intervals along the wireline until the wireline is inserted in the coiled tubing.

Abstract: The present invention is an apparatus for guiding a borehole servicing tool string into a sidetrack of a borehole.In one embodiment, a centralizer displaces a pivotally-mounted housing towards the sidetrack. A rounded nose on the bottom of the housing enables free passage of the housing into the sidetrack.In an alternative embodiment, a rounded nose is attached to a hinge at the bottom of the housing, and the tool housing is rotatably mounted to the tool string. The nose is displaced axially about the hinge, and the housing is rotated until the nose is aligned with the sidetrack as indicated by an orientation measuring device disposed within the housing.

Abstract: A discretized lithologic model of the subsurface is defined by a regular array of pixels. Each pixel corresponds to one of a finite number of possible lithoclasses such as sand, shale or dolomite. The lithoclasses are unknown except at a small number of sparsely distributed control pixels associated with borehole locations. Associated with each pixel there is a multivariate record of seismic attributes that may be statistically correlatable with the local lithology. A Monte Carlo method is used to simulate the lithoclass spatial distribution by combining the lithologic data at control pixels with the seismic-attribute data records. Using Indicator Kriging, a prior probability distribution of the lithoclasses is calculated for each pixel from the lithology values at neighboring pixels. The likelihood of each lithoclass is also calculated in each pixel from the corresponding conditional probability distribution of seismic attributes.

Abstract: A method and apparatus for acquiring a plurality of sidewall cores from an earth formation intersected by a wellbore while a coring tool is located downhole. A sidewall coring tool is provided having an internal core receptacle for receiving and storing sidewall cores in serial orientation. The coring tool incorporates a movable bit box providing rotary support and linear coring and retracting movement of a rotary coring bit. A bit box tilting and rotation actuator is incorporated within the coring tool for achieving breaking at the core sample from the formation and for selectively positioning of the bit box and rotary coring bit at a coring position where the bit is oriented in normal relation with the axis of the wellbore and a core ejecting position where the rotary coring bit is positioned in registry with the internal core receptacle for deposit of cores in serially oriented relation therein.