Abstract: The method of the present invention provides for processing seismic data over a subsurface area of interest. Downgoing seismic data, which may be VSP data, and surface seismic data are acquired over a subsurface area of interest. An inverse operator is determined from changes in signal characteristics, which may be first-arrival signals, between consecutive depth levels of the downgoing VSP data. The inverse operator is assigned to at least one surface seismic data level. Data levels may be in time or depth. Inverse operators may be interpolated for time or depth level operators for data samples between already determined operators. Inverse operators are applied to seismic data to restore attenuated signal components.

Abstract: The present invention provides apparatus and method for varying an operating parameter for a nuclear gamma ray tool for evaluating the integrity of gravel packing. The gamma ray output intensity and area of investigation are altered by changing a source housing geometry and the material from which the source housing is made. An actuator is provided to slide a variable electron density sleeve over the source and to vary the area of investigation by changing the distance between the source and a detector.

Abstract: Disclosed is a method of determining the extent of recovery of materials injected into a oil well comprising the steps of: a) preparing a material to be injected into an oil well; b) admixing therewith a chemical tracer compound at a predetermined concentration; c) injecting the admixture into an oil well; d) recovering from the oil well a production fluid; e) analyzing the production fluid for the concentration of the chemical tracer present in the production fluid; and f) calculating the amount of admixture recovered from the oil well using the concentration of the chemical tracer present in the production fluid as a basis for the calculation. Fluorinated benzoic acids are disclosed as a preferred tracer.

Abstract: The present invention provides apparatus and method for evaluating the integrity of gravel packing. A screen is disposed in an annulus between the wellbore and a production tubing. A tubing, such as a wash pipe, is placed inside the production tubing to provide a fluid path for the gravel slurry for gravel packing the screen. A self-contained memory logging nuclear tool is located in the tubing below (downhole) the screen. After gravel packing, the tubing with the tool is retrieved from the well at a selected speed. The tool is activated to record data in the memory carried by the tool as it passes across the screen. The data stored in the memory is downloaded at the surface to produce a log which provides a measure of the integrity of gravel packing of the screen.

Abstract: A jarring tool uses a button member to control the jarring sequence used to free an object lodged in a well bore. A preferred tool includes an anvil having a sleeve portion adapted to enter a bore of a hammer. The button member allows selective entry of the anvil sleeve into the hammer bore. A preferred telemetry link includes two or more at least partially conductive members in a telescopic relationship for exchanging electrical signals with the object. The members extend and retract to accommodate length changes of the jarring tool. An exemplary jarring sequence includes a loading phase, a release phase, and a reset phase. In the loading phase, the button member prevents hammer movement toward the anvil. During the release phase, the button member allows the hammer to be propelled against the anvil. In the reset phase, the hammer and button returns to their initial positions.

Abstract: The present invention provides a method of obtaining and processing seismic data to obtain enhanced geophysical maps from pre-existing 3D seismic data. A first set of data is obtained from a vertical seismic profile (VSP) survey and a second set from reverse seismic profile survey by reversing the locations of the sources and receivers of the VSP survey. The two sets of data are combined to determine a transfer function or model, which is then applied to a set of 3D seismic data to obtain a seismic map of the area surveyed for the 3D data.

Abstract: A pressure sensor comprising a first housing piece defining a lumen therethrough and an opening to said lumen to provide communication between said lumen and a sensing element, said first housing piece having a first surface surrounding said opening, a second housing piece shaped for mating with said first housing piece and providing, with said first housing piece, a region for containing a sensing element in position to communicate with said lumen via said opening, said second housing piece having a second surface that surrounds said region and faces and conforms to the shape of said first surface, said second housing piece including an end of an electrical wire and wire contacts that are electrically connected to said wire, having portions at or near said second surface, and are spaced from each other, a sensing element in said region in communication with said flowpath via said opening, said sensing element including sensor contacts aligned with respective wire contacts, and an elastomeric sheet providing

Abstract: A mercury pump for analyzing geological core samples has a vertically oriented cylindrical cavity in which a lower portion forms a mercury displacement chamber and an upper portion in axial alignment with it forms a sample chamber. A pressure transducer, e.g., a strain gauge or solid-state sensor, in communication with the sample chamber produces an electrical pressure signal. A screw ball jack urges a synthetic-resin piston upwards in the displacement section to push the mercury into the sample chamber. The displacement of the mercury is sensed by an electronic encoder coupled to the hand crank of the jack, and provides data regarding both the direction and the amount of piston displacement. A microprocessor-controlled volume-measuring device has inputs connected to the encoder, and automatically provides core sample data, in response to the signals from the encoder, at the end of a core test run.

Abstract: Compressibility test apparatus and method of testing compressibility. The apparatus includes a holder having a sample chamber for holding a sample in the environment of a confining pressure and means for supplying an internal pressure to the held sample. The sample and various conduits and channels that communicate with the sample define an internal system volume. Connected in this internal system volume is an internal volume adjustment pump that is operable to vary the internal system volume in incremental steps, by which the internal pressure is reduced (or increased) in steps to increase (or reduce) the net confining pressure. As a result, changes in the sample volume as a function of changes in the net confining pressure are determined, from which the compressibility of the sample is obtained.

Abstract: The permeability of a core sample is measured during nonsteady state flow of fluid therethrough. A predetermined test pressure is supplied to an upstream end of the core sample while that sample is disposed in a fixed, closed volume and is subjected to a constant, predetermined confining pressure. The change in pressure across the core sample, with the passage of time, is measured; and the permeability of the core sample is determined as a function of the time-related measure of pressure change.

Abstract: A viscosimeter measures the viscosity of a fluid, such as a petroleum hydrocarbon liquid, by driving a capillary through the fluid and measuring the pressure drop across the capillary. The viscosimeter comprises a pressure cylinder, a piston within the cylinder having at least one capillary tube, and an arrangement for driving the piston at a known speed so that the fluid is displaced at a known volumetric rate through the capillary tube. Pressure sensors on either end of the cylinder measure the capillary pressure drop. In a preferred embodiment, the piston has a main body and a selector plate. The main body has a plurality of capillary tubes each of a different bore size, and the selector plate is rotatable relative to the main body by rotating a selector handle outside the cylinder. An oven enclosure permits the cylinder, and its fill of fluid, to be heated in an air bath to reservoir temperatures.

Abstract: A core holder is used in the nonsteady-state testing of permeability and other flow characteristics of a geological core sample. A reference pressure reservoir assembly contains a predetermined volume of test gas at a known pressure, and a gas operated valve admits this test gas rapidly to the upstream end of the core sample. The downstream end of the core sample is open to the atmosphere, and the pressure in the reference pressure reservoir assembly is monitored as it decays in time while the test gas passes through the core sample. The gas-operated valve is formed of an upstream plug, a gland fitting the plug, and a valve stem fitting into a generally cylindrical cavity formed in the plug and gland. The valve stem has an enlarged head at one end with an annular slot on a cylindrical surface thereof. This structure minimizes turbulence in the flow of the test gas through the valve assembly.

Abstract: Apparatus for processing the output signal of a gas chromatograph. An interface device receives the analog output signal and digitizes it, reducing the effects of noise and preparing the signal for processing by a digital microprocessor. The microprocessor detects and measures peaks in the signal and determines the desired identification (in order of ascending molecular weight) and concentration (peak amplitude) data. A logarithmic output signal is produced for displaying output signals with wide dynamic ranges on a strip chart recorder.

Abstract: A viscosimeter having a first cell containing mercury or other electrically conductive fluid, a second cell containing a sample of fluid of unknown viscosity, and a pair of passages interconnecting the ends of the cells to form a closed circuit. A plurality of electrodes extend into the second cell in spaced relationship with each other along the cell's axis and are connected to an electrical circuit. Upon the opening of valves in the two passages, the conductive fluid urges the sample fluid through one of the passages and flows through the other passage into sequential contact with the electrodes in the second cell. The electrical circuit detects the rate of movement of the conductive fluid past the electrodes and produces an output signal related to the viscosity of the sample.

Abstract: A particle size analyzer of the sedimentation type in which a cup-shaped member is used to deposit the particles in the sedimentation fluid substantially simultaneously and at low velocity. The particles are ultrasonically dispersed as they are deposited in the fluid and are collected by a balance member which detects their receipt as a function of time. An electronic circuit connected to the balance member determines the size of the particles through the use of Stokes' Law and an empirically determined relationship between the settling velocity of the particles and their size.

Abstract: A method of coating a core sample in which a distillate such as petroleum jelly is applied to the exterior surface of the sample. A cylindrical mold is partially filled with a plastic mixture of hardenable epoxy resin and hardener therefor, and one end of the core sample is slowly inserted into the mold under a pressure which preferably is not more than about 50 pounds per square inch. In some cases the inserted end of the sample is pre-coated with the plastic mixture. As the insertion of the sample is continued, the mixture flows up the side of the sample and covers the opposite end. The coating is cured by maintaining it in the mold at room temperature for a period of time sufficient to enable the resin to set up and then by holding it at an elevated temperature for at least about eight hours. Upon the removal of the coated sample from the mold, the ends are cut off to expose the sample material.

Abstract: Apparatus for measuring the tension on a cable. A strain bridge with connective end sections and a central flexible web section is clamped to the cable. Any increase in the tension on the cable causes the end sections to separate slightly, elongating the web section. Attached to the web section are strain gauges, which detect the elongation of the web section. An electronic circuit receives the output of the strain gauge and produces an indication of the desired tension.

Abstract: A flame photometric detector for use with a gas chromatograph comprises a burner to produce a cool hydrogen flame and excite molecules of the gas sample to emit light characteristic thereof, a transparent chimney surrounding the burner and flame to enhance characteristic light emission, a selective light filtering means, and sensing means positioned so as to exclude the flame from its sensing area. The device and method of operation are characterized by a substantially broader range of detection and measurement than is possible with present commercially available equipment.