Abstract: An end-cap-to-piston coupling, with or without an integral load cell has been developed for triaxial test apparatus. One triaxial test apparatus shown has a housing, sample mounting apparatus in the housing, a load piston opening through the housing through which projects a load piston, and a load transfer coupling, with or without an integral load cell, interposed between the end cap and the load piston. In one aspect the coupling has a coupling body and a channel on one end into which the load piston is inserted to contact a shoulder of the coupling body. Another end of the coupling has a channel which receives a top end cap of a sample mounting arrangement. This channel may be sized and configured to receive a load transfer ball interposed between the coupling and the end cap or between the coupling and the piston. In one aspect a series of interchangeable top and bottom members are provided, each with a different diameter recess, to accommodate load pistons and sample end caps of different diameters.

Abstract: The current invention is an apparatus useful for generating seismic waves with an enhanced signal to noise ratio. The enhanced signal is produced at a fundamental resonant frequency, and multiples thereof, by producing a near zero acoustic pressure condition around and beyond each end of the apparatus having an intermediate acoustic source. Such a near zero acoustic pressure condition is established preferably by either (1) using two end acoustic sources to produce a destructive interference effect with the acoustic output of a third acoustic source postioned therebetween, or (2) using two active or passive end acoustic capacitors or resonators to produce a near zero impedance condition at each end of the apparatus. The enhanced signal may be produced over a range of frequencies, including both resonant and nonresonant frequencies, by creating a high impedance condition experienced by the intermediate source and hence a high acoustic pressure around the intermediate region of the apparatus.

Abstract: A non-upset tubing section, a tubular coupling, a connection for non-upset tubing sections, and a method for connecting the non-upset tubing section and the tubular coupling are disclosed. Methods for fabricating the non-upset tubing section and the tubular coupling are also disclosed. In one embodiment, the non-upset tubing section has an outer diameter of about 23/8 inches and, in another embodiment has an outer diameter of about 27/8 inches. The non-upset tubing section also has an externally tapered threaded surface having approximately eight rounded threads per linear inch. The tubular coupling has an outer diameter of about 27/8 inches, for use with at least one 23/8 inches OD tubing section, or about 31/2 inches, for use with at least one 27/8 inches OD tubing section. The coupling also has an internally tapered threaded surface having approximately eight rounded threads per linear inch and having a pitch diameter of about 2.258 inches for use with the 23/8 inches OD tubing section or about 2.

Abstract: A method for cascading or linking seismic vibrator sweeps to form a cascaded sweep sequence. According to the method, a first cascaded sweep sequence is generated containing N sweep segments linked end-to-end. The N sweep segments are substantially identical, except that the initial phase angle of each sweep segment within the sweep sequence is progressively rotated by a constant phase increment of about 360/N degrees. A second cascaded sweep sequence is generated consisting of (i) N consecutive sweep segments linked end-to-end which correspond to said first cascaded sweep sequence and (ii) an additional sweep segment linked to the N consecutive sweep segments which is positioned and phased so as to substantially suppress harmonic ghosts during correlation. One of these cascaded sweep sequences is used for the vibrator sweep sequence and the other is used for the correlation reference sequence.

Abstract: The orientation of vertical fractures in subsurface rock formations is determined. A cross-dipole logging tool collects four-component shear-wave seismic data through a formation interval of interest in a subsurface formation adjacent a well bore. A gyroscope is typically provided to indicate compass orientation of the logging tool. The collected seismic data are then transformed within a time window containing arrivals of the shear waves to a new coordinate system within which the motion of the shear waves becomes linear. In the new coordinate system, the shear wave data are processed to determine the presence and orientation of fractures in the formation.

Abstract: Radar is used to detect and map near-surface geochemical alteration of rock and soil. The radar waves penetrate a buildup of carbonate and silica on the earth surface above micro-seepage of hydrocarbons dissolved in water. The hydrocarbon source may be an oil or gas reservoir buried many thousands of feet, or it may be from near-surface, man-made features. The thickness and sensitivity of the buildup is related to the size of the underground source or reservoir. Radar echoes from the bottom of the buildup provide a reservoir detection and mapping tool.

Abstract: A method for processing seismic vibrator data. The method utilizes a deterministic signature deconvolution of the vibrator data to compress the impulse response of the data resulting in sharper, clearer seismic images than are possible using cross-correlation techniques. The method may be used in place of or in addition to cross-correlation. Further, the method may be implemented in either the time domain or the frequency domain.

Abstract: Presented is a process for use in the area of geophysical data processing, for computing a three dimensional grid of traveltimes from a three dimensional grid of velocities. The process involves a finite-difference solution to the eikonal equation in spherical coordinates, with refinements which increase the stability of the calculation and cope with numerical roundoff error as well as turned ray problems. The resulting three dimensional grid is not only useful in itself in providing information regarding the subsurface, but also can be used in depth migration, velocity analysis (especially three dimensional tomography) and in raytracing (leading to modeling of synthetic seismograms, three dimensional traveltime inversion, and map migration). This method is preferably executed on a computer, and can be performed either on a mainframe or on a massively parallel processor.

Abstract: A method for suppressing or removing coherent noise from seismic or borehole data is disclosed. The method requires horizontal alignment of the traces, comparison of the amplitude, phase and/or shape of neighboring traces, and subtraction of traces from neighboring traces only where the local correlation is high.

Abstract: A method of correcting a seismic pulse waveform for use in deconvolution of reflected pulse data. The source pulse waveform is measured by a hydrophone positioned vertically beneath the acoustic source. The phase error is calculated based on the depth of the source and the depth of the measuring hydrophone. The calculated error is subtracted from the phase spectrum of the measured waveform. The resulting waveform provides an accurate representation of the true far field waveform, leading to an improved expression of the waveform actually incident upon the marine floor.

Abstract: A well system, and a method for installing the well system, for use in producing hydrocarbons from a subterranean reservoir located beneath a body of water is disclosed. The well system is intended for use in conjunction with a bottom-founded offshore platform. The inventive well system eliminates the conductors traditionally used in offshore platform well systems. According to the invention, a subsea guide template and an outer casing string extending downwardly from the guide template to a first predetermined depth less than the depth of the reservoir are installed prior to installation of the offshore platform. Thereafter, the platform and the first intermediate casing string are installed, in either order. Drilling for the first intermediate casing string takes place in the open hole defined by the outer casing string with all returns of drilling fluid and drill cuttings occurring at the seafloor.

Abstract: The current invention is an apparatus useful for generating seismic waves with an enhanced signal to noise ratio. The enhanced signal is produced at a fundamental resonant frequency, and multiples thereof, by producing a near zero acoustic pressure condition around and beyond each end of the apparatus having an intermediate acoustic source. Such a near zero acoustic pressure condition is established preferably by either (1) using two end acoustic sources to produce a destructive interference effect with the acoustic output of a third acoustic source postioned therebetween, or (2) using two end acoustic capacitors or resonators to produce a near zero impedance condition at each end of the apparatus. The enhanced signal may be produced over a range of frequencies, including both resonant and nonresonant frequencies, by creating a high impedance condition experienced by the intermediate source and hence a high acoustic pressure around the intermediate region of the apparatus.

Abstract: This invention relates to an improved method for recovering oil from a subterranean formation comprising sequentially injecting into the formation through an injection well in communication therewith: (a) a slug of an aqueous solution containing a high concentration of a gas mobility control agent; (b) a slug of an aqueous solution containing a low concentration of said gas mobility control agent; and (c) gas as the primary oil displacing fluid selected from the group consisting of carbon dioxide, hydrocarbon gas, inert gas and steam whereby said gas and said slugs of aqueous solution containing the gas mobility control agent form a mixture in the formation that significantly reduces gas mobility in the more permeable regions of the formation.

Abstract: The current invention is an improved method for preventing annular fluid flow following primary cementing of a casing string in a wellbore. The method involves injecting high pressure pulses of a working fluid into a liquid-filled casing string to produce tube waves that will propagate through the casing liquid until they encounter a casing restriction or barrier. This encounter vibrates the casing string. Vibration of the casing string helps to maintain the pressure of the cement slurry at or above the pressure of fluids in the surrounding formations, thereby preventing or reducing annular fluid flow.

Abstract: Load cell having a body with a ball recess therein and a ball removably disposed in the recess above a strain gauge means disposed in the body centrally below the ball recess, the load cell useful in measuring samples of geologic materials, e.g., core samples and for methods and apparatuses for measuring ultrasonic velocities in materials, particularly in the triaxial testing of low permeability rock samples.

Abstract: A method for producing simple seismic wavelet shapes with minimal side lobe energy for use as reference signals for seismic vibrators is disclosed.

Abstract: A method is provided, based on assigned drilling variables, for predicting the area of open region above a bed of cuttings resulting from drilling a high-angle well. The area of the bit used in drilling is compared with the area of the open region and drill pipe to determine a Hole-Cleaning Ratio. Occurrences of sticking of drill pipe or other drilling problems in prior-drilled wells are correlated with Hole Cleaning Ratio in those wells to determine a relationship for predicting risk of drilling problems in wells of interest. Risk factors so determined are used to modify conditions or equipment during drilling or to plan future wells.

Abstract: A method for horizontal mating of multiple floating sections of an offshore platform using a single point mooring is disclosed. The single point mooring is installed at a predetermined mating site. The first section of the platform is transported to the mating site. Anchor handling vessels tow the section to the single point mooring and connect it to that mooring. Subsequent sections of the platform are then transported to the mating site while an anchor handling vessel attends to the horizontally floating moored sections. When all sections have been mated together at the mating site, the platform is disconnected from the single point mooring and towed to the installation site.

Abstract: A specialty boom and outrigger apparatus and method for use with an offshore skimmer device and a floating vessel for corralling buoyant substances. The apparatus has an elongated flexible boom with floating members and is connected to an elongated towing member with guide members. The towing member is connected to a mast with guide members and the mast is connected with a vessel with guide members.

Abstract: A marine geophysical prospecting system employs a hydrophone streamer cable containing electromagnetic field sensors, modified to be towed at a preselected distance above the sea floor by a first marine vessel senses electromagnetic energy from selected substrata beneath bodies of water. The voltage between sensors may be amplified by amplifiers in the cable or by amplifiers aboard the towing vessel. Optionally, a second similarly modified cable is preferably located above the near-bottom cable. Both cables may also contain hydrophones and/or accelerometers, as well as depth and position sensors. Optionally, a second vessel tows at least one conventional seismic source to create compressional energy which propagates downwardly through the water into the substrata beneath the body of water. At appropriate porous subsurface formations, the acoustic energy is converted to electromagnetic energy.