Abstract: A system and method for mating a preconstructed integrated deck mounted on a barge with a previously installed offshore jacket is provided. The system comprises at least two primary load transfer units, at least one secondary load transfer unit, and a plurality of drop block assemblies. The primary load transfer units are designed to absorb a portion of the weight of the integrated deck as the integrated deck is lowered onto the jacket. The secondary load transfer units are designed to engage after a portion of the weight of the integrated deck has been absorbed by the primary load transfer units and to assist the primary load transfer units in absorbing an additional portion of the weight of the integrated deck as it continues to be lowered onto the jacket. The drop block assemblies are designed to disengage the integrated deck from the barge and thereby transfer the remaining weight of the integrated deck to the jacket.

Abstract: A sound source capable of generating high energy acoustic pulses is lowered into a well borehole. A chamber of high pressure air in the source provides the energy for the pulses. A firing mechanism in the source is armed using increased pressure on the drilling mud in the well borehole. The pressurized mud is stored in a chamber in the source having closable ports. When the firing mechanism is operated, the ports are open, forcing the mud from the source into the borehole mud column and causing a cavitation zone in the mud at the ports. When the cavitation zone collapses, an acoustic energy pulse is formed. Pulses may be formed in this manner at the same depth or a number of depths in the well bore during a single run of the source in the well.

Abstract: A releasable latch-type connector for a tension leg platform tether. A tether portion of the latch is provided with an annularly arranged set of shear lugs. The tether portion of the latch is adapted to be received within a generally cylindrical second portion of the latch. The second portion of the latch is also provided with an annularly arranged set of shear lugs. The two sets of shear lugs are arranged so that the tether portion of the latch may be inserted into the second portion of the latch and then rotated and lifted to cause the two sets of shear lugs to come into abutment, preventing further withdrawal of the tether portion of the latch. This connector is particularly well suited for securing the lower end of a tension leg platform tether to a foundation on the ocean bottom.

Abstract: A fatigue-resistant threaded connector for connecting adjacent sections of a tubing string subject to cyclic dynamic stress variations is disclosed. The connector comprises a pin member which is threadedly engageable with a corresponding box member. In its preferred embodiment, the connector is radially preloaded. The connector has tapered threads with a straight load path having substantially no eccentricity. The preferred thread form is a modified buttress thread having a zero (or near zero) degree load flank, a 45 degree stab flank, and a large root radius. Additionally, the thread may include a small stab flank relief to reduce stress concentrations, and a differential between the pitch of the pin threads and the pitch of the box threads to compensate for the Poisson's ratio effect of the radial preload. The connector utilizes an elliptical stress relief groove at the base of the pin threads and elliptical contours on all thickness transitions to reduce peak stresses.

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 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 method for restoring to filtered seismic data at least some of the ramdom background noise associated with the data in its form prior to filtering. The method includes the steps of filtering seismic data in a two-dimensional filter; generating a noise signal representing the random background noise associated with the data; filtering the noise signal in an inverse filter corresponding to the two-dimensional filter; and adding the inverse-filtered first signal to the filtered seismic data. In one embodiment, the noise signal is generated by filtering a copy of the data in a least-mean-squares adaptive filter to remove substantially all coherent energy therefrom. In another embodiment, the noise signal is an independently generated white noise signal having beginning and end times matching those of the seismic data. This white noise signal is the bandpass filtered to cause its frequency content to match that of the seismic data.

Abstract: A method and apparatus for orienting a flowline so that it may be remotely connected to a riser connected to an offshore structure. The apparatus includes a structural guide, connected to the offshore structure, that is capable of being rotated so that the front side of the structural guide is directed toward the lead end of the flowline. The structural guide is designed in such a manner so that is is automatically rotated by the cable which is used to pull the flowline to the offshore structure when tension is applied to the cable. The lead end of the flowline is directed upwardly by a pipe guide. The pipe guide has riser guidepost recepticals that receive guideposts as they are lowered from the offshore structure by guidelines. The guidelines and guideposts direct the riser into position over the lead end of the flowline for final connection.

Abstract: A system for mating an integrated deck structure with an offshore substructure is provided. The system comprises a spud can attached to a leg of the integrated deck structure and a bin attached to a leg of the substructure for receiving the spud can. The bin contains a bed comprising a medium having variable stiffness and damping characteristics which is utilized to minimize the dynamic forces that occur between the integrated deck structure and the substructure during the mating procedure.

Abstract: Method and apparatus for digitally deriving arrays from seismic data. Indentical parallel processing elements connected between common input/output buses are each preselected to derive different pluralities of arrays. Array specifications defining the arrays are downloaded into the processing elements. A scan sample set of spatially distributed seismic receivers is periodically generated and placed on the input bus. Each processing element, in response to array specifications, captures and stores all receiver output signals in the scan required to derive its respective arrays, derives its assigned arrays, and delivers resultant array samples to the output bus. Double input and output buffering in the processing elements is provided whereby receiver capture, array derivation, and outputing processes occur simultaneously in each processing element.

Abstract: A remotely-controllable, surface-referenced paravane for use in towing an object in a body of water at a controlled lateral offset from the pathway of the towing vessel is disclosed. The principal components of the paravane are a buoyant hull, a cambered hydrofoil shaped keel attached to the bottom of the hull and extending generally downwardly into the body of water, a remotely-controllable steering means, and a tow cable which connects the paravane to the towing vessel. Passage of the cambered hydrofoil shaped keel through the water generates a lateral force, similar to the lift generated by an airfoil, which causes the paravane to move laterally away from the pathway of the towing vessel in the direction of the lateral force. The remotely-controllable steering means is used to compensate for changes in the speed of the towing vessel or variations in wind, waves, or currents so as to maintain the lateral offset of the paravane within certain limits.

Abstract: A flexible structural joint of "flex joint" for use in an articulated structure is disclosed. The articulated structure has a first section and a second section which are located along a longitudinal axis of the structure, the first section being subject to lateral or transverse loads. The flex joint is located between the first and second sections and accommodates lateral pivoting of the first section with respect to the second section through elastic flexing or bending of certain of its members. No moving parts are used. In a first embodiment, the flex joint consists of an elongated axial load member and at least three shear and torsion links oriented so as to lie substantially in a plane perpendicular to the longitudinal axis of the structure. Each of the links is connected at one of its ends to the first section and at its other end to the second section.

Abstract: The invention is a multi-port, multi-chamber, tuned, air-powered subsea seismic source. It is suitable for producing a seismic wave in a subsea environment during seismic prospecting. Interconnected pressurized chambers are formed between plates located on a movable shuttle and cylinder walls extending inward from the source housing. The source is fired by moving the shuttle through a stroke and allowing the pressurized air within the air chambers to exit through ports into the surrounding water. A unique seal arrangement in also shown.

Abstract: The invention relates to a compact tunable subsea seismic source. The source has multiple seismic radiating plates placed symmetrically about a central housing which contains a hydraulic actuating system. The source is towed to optimize the amount of energy applied to the surrounding water.

Abstract: A hybrid offshore structure for conducting petroleum drilling and producing operations in very deep waters is disclosed. The structure consists primarily of a substantially rigid lower section extending upwardly from the bottom of the body of water to a pivot point located intermediate the bottom and the surface of the body of water, a compliant upper section extending upwardly from the pivot point to a deck located above the water surface, pivot means located proximate the pivot point and adapted to permit the compliant upper section to pivot laterally in response to environmental loads, and torsion means adapted to transmit torsional loads from the compliant upper section to the substantially rigid lower section. The lower section may comprise either a conventional trussed steel frame fixed to the bottom of the body of water by a plurality of piles or a concrete or steel gravity base. The compliant upper section may optionally be either a guyed tower or a buoyant tower.

Abstract: The disclosed device is a marine seismic source which produces a varying FM signal often in the 10-100 Hertz region of the spectrum. The seismic source uses stiff oscillating radiators to create a signal in the water. These radiators are actuated by hydraulic cylinders which are in hydraulic communication with hydraulic or oleo-pneumatic variable devices acting as springs with a variable spring rate. Variation of the spring rate as a function of the frequency permits the device to be tuned for maximum power output.

Abstract: A method and apparatus for cleaning debris from the interior surfaces of two flowlines, particularly dissimilar sized flowlines, utilizes a crossover flowline, crossover valve, and two bypass flowlines and bypass valves, wherein the bypass flowlines communicate between a respective flowline and the crossover flowline.

Abstract: A method for controlling sand production by consolidating an incompetent formation is disclosed. In this method, elemental liquid sulfur is suspended in steam which is injected into the formation. The sulfur reacts with the in-place hydrocarbon to form a consolidating agent.

Abstract: A method and apparatus for determining the distance and angular orientation between two structurally unconnected members, such as two sections of a subsea pipeline, is disclosed. The apparatus of the invention comprises generally two guide posts fixedly disposed, respectively, in known spaced relationships to the two structurally unconnected members and a remotely operable template. The remotely operable template comprises generally a variable length frame member; two guide members movably secured, respectively, to the outer ends of the variable length frame member and adapted to mate, respectively, with the guide posts; positioning means associated with each guide member and its respective guide post for properly positioning each guide member on its guide post; and means for measuring the distance between the outer ends of the variable length frame member and the angular orientation of each guide member after the guide members and the guide posts have been properly mated.

Abstract: The disclosed device is a marine seismic source which emits a constantly varying FM signal in the 10 to 100 H.sub.z range. The seismic source utilizes an adjustable length cantilever spring rotatably attached to stiff acoustic radiators, which create a signal in the water. Varying the length of the cantilever spring as a function of the frequency will permit the device to be continuously tuned for maximum power output.