Abstract: A method is disclosed to provide optimal or near-optimal vertical stacking of seismic records within the constraints imposed by real time data acquisition procedures. This method is characterized by forming output seismic traces which are a sum of prorated input traces, such proration being performed by application of smoothly varying weight functions derived from estimated signal and noise power levels within each input trace. Each weight function is computed using frequency domain filtering techniques to obtain a well behaved bandlimited time series for each function. The method also includes a procedure for clipping grossly large noise spikes in the input traces before the stacking procedure is performed, thereby guarding the weight calculation procedure against aliasing effects induced by such spikes.

Abstract: Described herein are a system for securing and tensioning the tethers 12 of a tension leg platform 10 and a TLP installation method incorporating such a system. The tethers 12 preferably extend upward from the ocean bottom 16 to a position slightly below the bottom of the unballasted TLP hull 20. At least one tether tensioning tool 26 is situated within the hull 20 for lowering a tether extender 22 to each tether 12 and then biasing each tether-tether extender unit upward to tension the tether 12. The use of a removeable tensioning tool 26 avoids the need for a dedicated tensioning system for each tether 12. The tensioning system 28 of the present invention permits use of a simplified method for installing a TLP 10. Because the tethers 12 extend to an elevation which, at least initially, is below the draft of the TLP hull 20, the tethers 12 may be installed offshore prior to hull installation.

Abstract: An improved method and apparatus for initiating seismic data storage in an Isolated Distributed Recording System. An encoded acoustic signal is generated by an acoustic energy source which is detected at an isolated distributed recorder where it is correlated with a preselected correlating signal. Upon sufficient correlation between the encoded acoustic signal and the preselected correlating signal, seismic data are stored. In the preferred embodiment, the invention relates to a method and apparatus for generating an encoded seismic signal utilizing a seismic energy source. The encoded seismic signal is correlated with a preselected correlating signal at an isolated distributed recorder; upon sufficient correlation between said signals, the isolated distributed recorder is triggered to store incoming seismic data commencing at the time the seismic data were generated and extending for a predetermined time interval.

Abstract: A method for determining at wellsites the swelling-clay content of shales and shaly sandstones earth formations whereby a sample of the formation is washed with a fluid having a water activity substantially less than that of water, which fluid may contain a soluble cation, and measurements of the sample's dielectric constant are made at a preselected frequency for subsequent comparison to calibration curves, thereby obtaining a measurement of the welling-clay content of the formation. The determinations of the swelling-clay content may be performed at different levels depending on the nature of the samples.

Abstract: An endfire seismic array comprises one or more marine seismic cables having a plurality of acoustic-to-electrical hydrophone receivers spaced therealong, each being operatively connected in combination so that as a unit an endfire receiving beam pattern with respect to any frequency across the seismic band is formed by causing the signals from the individual hydrophone receivers to be additive for that frequency. A plurality of cables results in a more narrow beam than a single cable. A geologic or lithologic formation that is a dip change from the norm may be detected either as an extra strong increase or decrease in signal, depending on the mode of use.

Abstract: A hydrostreamer includes connectors for joining to depending housings enclosing geophone sensors. These sensors are coupled to the bottom of the sea via such housings by the housings being appropriately weighted and externally surface serrated. Thus, the geophones detect s-waves directly from the ground in single-mode conversion fashion while simultaneously, hydrophones in the hydrostreamers detect p-wave reflections in traditional fashion.

Abstract: A method and system for reducing the oil concentration of a produced, hydrocarbon-containing fluid to no more than about 10 ppm and softening the deoiled fluid to reduce scale-forming constituents. The method and system are capable of treating fluids having temperatures within the range from approximately 120.degree. C. to approximately 160.degree. C., without the need for cooling the fluid to perform either the deoiling step or the softening step. In a preferred embodiment, the deoiling step is performed by first filtering the hot fluid in a first set of coalescing filters and then in a second, identical set of coalescing filters, and the softening step is performed in a thermal softening unit wherein steam is directly sparged into the deoiled fluid in a reaction zone under pressure sufficient to prevent boiling at the reaction zone temperature.

Abstract: A system for analyzing thin section images is disclosed. A microscope scans a thin section impregnated by a dyed epoxy and develops a digital representation of the color image of the thin section. A classifier defines the areas of the image which are identified as pore space. The color image is then transformed into a monochromatic image by transforming the color image onto the principal axis representing the brightness of the color image. Each discrete feature representing grain space or pore space in the monochromatic image is defined by analyzing the uniform brightness distribution of the region. Finally, the boundary of each discrete region can be processed to ascertain the size, shape, orientation and roundness of the region.

Abstract: A heave compensated stabbing and landing tool and method for use on a floating platform comprises a tool attached to a heave compensator on the floating platform. The tool, attached at one end to a taut line anchored to the seabed, includes means for gripping, raising and lowering a tubing string. The tool is attached to the heave compensator, which is raised to tighten the anchor line and substantially eliminate relative motion between the end of the tubing string and the seabed. The tool grips the tubing string and lowers it to the seabed in a controlled manner.

Abstract: A process is described for removing contaminants from a contaminant-laden solution of dialkyl ethers of polyethylene glycols (polyether solvent) by mixing the solution with an aqueous base solution. The mixture produces at least two liquid phases of different densities, which are then separated from each other. The lighter liquid phase is predominantly the polyether solvent while the heavier liquid phase is predominantly the aqueous base solution and the contaminants. The process is particularly useful in removing triethylene glycol and other glycol-based dehydration solvents.

Abstract: The multipole shear wave logging device of this invention includes a logging sonde, means for generating a 2.sup.n -pole shear wave in an earth formation surrounding a borehole containing liquid where n is an integer greater than 2, and means for detecting in the liquid the refraction of the 2.sup.n -pole shear wave. In the preferred embodiment the generating means comprises six similar sectors of a hollow piezoelectric cylinder. The six sectors are polarized radially and are so connected to the sonde that they are in the form of a split cylinder coaxial with the sonde axis. Electrical pulses of similar wave forms are applied across the inner and outer cylindrical surfaces of each sector. The electrical pulses are of such polarities that adjacent sectors vibrate radially in substantially opposite phase. Circumferentially polarized sectors may also be used in the place of radially polarized sectors.

Abstract: A load transfer system and method for its use for mating an integrated deck structure onto an offshore platform substructure at an offshore location is disclosed. The load transfer system utilizes a probe extending downwardly from the integrated deck and adapted to mate with the substructure, and a shock-load absorbing system having a first spring with a linear compressive response and a second spring with a variable compressive response mounted in series between the integrated deck and the probe.

Abstract: A centrifugal method and apparatus capable of separating a fluid stream composed of a plurality of components with differing specific gravities. The stream contemplated for separation is that of a producing oil well with components of oil, water, natural gas, and particulates. The method and apparatus use centrifugal forces to separate the gaseous, solid, and liquid components from each other. After separation is completed, detector and sensor arrangements are used to maintain liquid levels in the separator and to control the removal of the individual separated fluids from the apparatus.

Abstract: A detailed seismic survey is achieved when there is general knowledge of a formation with generally steep dip by first locating the central location point and then mapping radial shot lines and receiver lines therefrom. The shot lines need to extend across the dip and beyond. The receiver lines need to extend a normal distance as with conventional 3-D seismic surveys. Shots from the central location progressing outwardly will reflect first with equal incident and reflector paths, then with a short incident to long reflector path, and finally to where long incident and short reflector paths are achieved. The data collected radially to describe the formation is near one-tenth of that required for conventional 3-D surveys where the shot lines and the receiver lines are mapped in parallel survey lines.

Abstract: An acoustic borehole well logging method and apparatus for measuring azimuthal anisotropy of a formation traversed by a borehole using at least one multipole transducer. In a preferred embodiment, a dipole wave transmitter and at least one detector sensitive to dipole waves are employed. In an alternative preferred embodiment, a monopole transmitter and at least one multipole detector are employed. In the inventive method, two acoustic wave arrivals are detected, each associated with a different azimuthal orientation relative to the longitudinal axis of the borehole (i.e. each is transmitted by a multipole transmitter oriented at such angle, or is detected by a multipole detector oriented at such angle, or both). The inventive apparatus preferably includes at least one transducer unit including two or more multipole transmitters (or two or more multipole detectors) oriented at different azimuthal angles relative to the tool's longitudinal axis.

Abstract: A method for constructing inspectable welded joints which are resistant to marine biofouling, and the welded joints formed thereby, are disclosed. The method comprises bonding a first coating of a substantially dielectric material to the welded joint and bonding a second coating of a marine growth-inhibiting material to the first coating. The first coating preferably is less ductile than the underlying welded joint. The second coating is electrically insulated from the underlying welded joint by the first coating and provides a source of a biocide which prevents the accumulation of marine biofouling encrustations. Fatigue cracks occurring in the welded joint propagate through the coatings and are readily visible on the outer surface of the second coating. Further, fatigue cracks in the welding joint may be detectable through the use of nondestructive testing techniques prior to the time when they are visible on the outer surface.

Abstract: A subsea guidepost latch mechanism which latches a guidepost to a guidepost-receptacle by means of an external snap ring on the guidepost and an internal groove in the guidepost-receptacle. The snap ring is held in the groove by a collet inside the snap ring which is forced outward by an inner mandrel in the guidepost when upward tension is placed on the mandrel by a guideline. The guidepost is released from the guidepost-receptacle by releasing tension on the guideline which allows the mandrel to drop, releasing outward force on the collet and the snap ring. This allows the snap ring to be pulled out of the guidepost-receptacle groove.

Abstract: A method and structure for protecting an offshore structure in an arctic body of water from mobile ice, waves, and currents. Soil is dredged from the floor of the body of water, deposited in a berm having a size and shape adapted to protect the offshore structure, and strengthened in place by mixing cement with a portion of the soil in the berm. The space between the berm and the offshore structure is filled with unstrengthened soil fill.

Abstract: A method for recovering oil from a subterranean formation is disclosed wherein an aqueous surfactant solution is injected into the formation to reduce the mobility of gas in a gas-flooding process. The gas may include hydrocarbon gas, inert gas, carbon dioxide, and steam. The surfactant is represented by the general formula ##STR1## where R is a linear or branched chain alkyl group with n carbon atoms wherein n ranges from 0 to about 18, except that if the gas is steam n ranges from about 9 to about 30;x ranges from 0 to about 20 and y ranges from 0 to about 20, provided x+y does not exceed about 20;R' is a linear or branched chain alkyl group with m carbon atoms wherein m ranges from 0 to 4, except that if the gas is steam m ranges from 1 to 4, with the proviso that the sum of x+y+m is at least one; andeach M.sup.+ is a cation.

Abstract: The invention is an underwater LNG pipeline system in modular sections wherein multiple LNG pipelines utilizing expansion joints to compensate for contraction are connected together by braces to form an integral frame, and including pressure vessels enclosing the expansion joints to permit access to the expansion joints for inspection or maintenance. In a second embodiment, the frame is a separate elongate space frame connected to the pipeline and the pressure vessels. In a third embodiment, the pipelines are INVAR steel and no expansion joints or pressure vessels are included.