Abstract: A method and apparatus for establishing the rate at which fluid is transferred between an offshore well 16 and the formations 20 surrounding the well 16 in the course of drilling the well 16 from a floating drilling rig 14. A drilling fluid handling system 31 is used to inject drilling fluid into the well 16. A marine riser 22 extending from the sea bottom 18 to the rig 14 is provided to return the drilling fluid to the rig 14. The riser 22 is provided with a slip joint 26 to accommodate wave induced heave of the rig 14. Inflow and outflow flowmeters 42,44 are provided to monitor the rates at which drilling fluid is injected into the well 16 and returned to the rig 14. The return flow rate signal is filtered to mitigate the cyclical variations resulting from extension and contraction of the slip joint 26. A signal processing system 46 is provided to maintain the time constant applied in the filtering process at an optimum level as the rate and magnitude of rig heave varies with time.

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: An anode pod system for cathodically protecting offshore structures and method of installing the system in which a set of anode pod units are individually placed on the ocean floor adjacent an offshore structure. Each anode pod unit comprises a plurality of anodes attached to a top tubular ring and a base tubular ring larger than the top tubular ring to form a conically-shaped unit. An electrical conductor cable connects each anode pod unit to the offshore structure.

Abstract: A method for conditioning the virgin drainage area of a tar sand formation that is penetrated by a well for enhanced petroleum production by cyclic steam stimulation is described. The method comprises fracturing the drainage area by injection of liquid carbon dioxide. While carbon dioxide is still in place within the formation, steam is injected into the formation. After a suitable soaking period, the well is opened to production. This method achieves better petroleum recovery than conventional huff-puff steam stimulation techniques.

Abstract: The disclosure describes apparatus for mooring a vessel 10 in unprotected waters. The vessel 10 contains a recess 34 in its hull adapted for receiving a buoyant mooring element 18. The mooring element 18 is attached to the ocean floor 12 by a plurality of mooring lines 20. Means are provided for releasably securing the mooring element 18 within the recess 34. The buoyancy of the mooring element is established such that on release from the vessel 10 it sinks to a predetermined depth a spaced distance above the ocean floor. The apparatus of the present invention is especially well suited for mooring a hydrocarbon storage tanker proximate the terminus of a production riser in waters subject to ice floes.

Abstract: The preferred embodiment of this invention includes a logging sonde, an elongated pair of oppositely polarized piezoelectric plates connected to each other by their flat surfaces, and an electrical pulse applying means for applying electrical pulses across the pair of plates so as to bend and vibrate the plates in a direction perpendicular to the length of the plates. Vibration of the plates in a fluid contained in a well creates in the fluid a positive compressional wave in one direction and simultaneously a negative compressional wave in the opposite direction. The two compressional waves will interfere to produce a dipole shear wave in the earth surrounding the well. The dipole shear wave arrival is detected at two locations in the fluid spaced longitudinally along the well from each other and from the plate.

Abstract: A removable porous layer is placed on the outside of various well implements. The layer allows movement of liquid toward sites of localized low pressure and therefore prevents differential pressure stickage of the well implements on the borehole wall.

Abstract: A mechanism for decoupling over a selected angle the rotational motion between a marine vessel moored to a single point mooring system such as a single anchor leg mooring (SALM) and the fluid swivel stack of the single point mooring system. The mechanism includes two spaced-apart stops attached to the fluid swivel stack and a coupler positioned between the stops and attached to a mooring swivel at the base of the fluid swivel stack. Shock absorbers may be positioned on each stop between the coupler and each stop.

Abstract: Certain high strength alloys lacking resistance to hydrogen embrittlement are cold worked and heat treated utilizing critical preselected conditions to result in a unique alloy having increased resistance to hydrogen embrittlement without unacceptable loss of strength. It is theorized that this unexpected improved resistance correlates with the concentration of certain elements, such as phosphorus and sulfur as impurities on the crystallographic boundary surfaces of the alloy.

Abstract: To improve the separation of a produced oil-water emulsion containing a surfactant, the emulsion parameters of temperature and salinity are brought within certain critical limits. The emulsion will separate into an injectable brine/surfactant phase and a pipeline quality crude oil phase. The operable salinity range is from about 70% to about 130% of the reservoir salinity, and the operable temperature range is from about 75.degree. F. lower to about 75.degree. F. higher than the temperature of the reservoir from which the emulsion was produced.

Abstract: The invention is a system for reducing offset in an analog to digital conversion system. A signal representing the system offset is stored in digital form. A digital to analog converter generates an analog feedback signal in response to the stored digital signal. The output of the system analog to digital converter is periodically sampled to update the stored digital word representing system offset.

Abstract: The apparatus and method disclosed prevents hydrate formation in subsea oil and gas pipelines including at least one marine riser. The invention reduces the pressure on the fluids in a shut in pipeline by displacing fluids in the system into a reservoir thereby reducing the height of the column of fluids in the riser. A pump may be used to remove additional fluid from the fluid reservoir and pipeline to ensure the hydrostatic pressure associated with the final fluid level is below the pressure where hydrates may form at shut in temperatures. During start-up, a pump removes fluids from the fluid reservoir at about the same rate as produced fluids are allowed into the pipeline. The pump is shut down and pipeline operations are resumed when the liquid full wellstream fluids in the pipeline warm to a temperature outside the range where hydrates may form.

Abstract: The invention relates to a self-cleaning, self-aligning, downhole make and break mechanical and electrical latch subassembly used in conjunction with logging vertical and deviated boreholes. The latch subassembly uses a pair of rings to self-align the male probe into the female receiver. A debris deflector surface and specially sized debris exit ports are provided to allow the mating of the parts without interference from extraneous downhole debris.

Abstract: A cable connector is provided which is particularly suitable for connecting tensioned armored cable sections used in wireline measurement while drilling operations or well logging operations. The cable connector comprises a pair of field latchable housings each attached to the braided outer covering of a cable, so that cable tension is transferred to the housings. The electrical connection between the inner flexible conductor wires of the armored cables is sealed from the environment within the housing by an elastomeric boot, with the boot being loosely positioned within the housing chamber by the flexible conductor wires. The housing need not isolate the electrical connection from the drilling fluids within the drill string, and the simplicity of the cable connector enhances both reliability and drill site assembly and repair.

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: An improved offshore platform base (12) is disclosed having three sets of substantially parallel bulkheads (24, 26, 28) which intersect one another at about 120.degree. forming a repeatable array of contiguous triangular (30) and hexagonal-shaped (34) chambers.

Abstract: A mechanism for releasing a pre-installed pile attached to a pile guide connected to an offshore platform is supported in the pile and includes pile latch means rotatable from a latch position in which one end extends through an opening in the pile and engages the upper end of the pile guide to a retracted unlatched position in which the entire latch means is located within the pile. The inner end of the latch means is connected to a collapsible compression linkage assembly which when in one position maintains the latch means in its latch position and when moving from the one position to another collapsed position causes the latch means to rotate to its unlatched position within the pile. A slide plate capable of causing the linkage assembly to collapse when moving downwardly from a first position to a second position is releasably held in the first position by shearable means.

Abstract: A method and apparatus for diverting a portion of a two-phase fluid from a trunk pipeline, having a known flow profile, into a branch pipeline while maintaining substantially equal quality in both pipelines. Openings are placed in the trunk pipeline wall such that fluid samples which approximate the flow profile are withdrawn through the openings. The withdrawn fluid is collected in an enclosed chamber and transported through the branch pipeline.

Abstract: A method and apparatus for removing oil from the surface of a body of water, subtidal seafloor, a riverbed, a shoreline or a beach are disclosed. The method employs a sweeping action of oleophilic bristles comprising at least one brush to remove oil from such a surface and a suction means to remove oil from the bristles. The apparatus comprises one or more oleophilic bristled brushes connected to a support means. The brushes are positioned so that they have a lower portion in contact with the oil and an upper portion above the oil. A motor means moves the brushes so that the oil is drawn into the brushes. A suction means, such as an air conveyor system, removes the oil from the brushes.

Abstract: A method and apparatus for diverting into a branch line a portion of a gas-liquid flow stream from a two-phase flow trunk line. Each of two or more takeoff pipes withdraw a two-phase portion of the trunk line flow stream and transmit it to a single common branch line. The takeoff pipes are oriented to produce branch line flow of predetermined quality. The quality of branch line flow may be monitored and control valves positioned in one or more takeoff pipes and in the branch line to facilitate branch line flow of variable quality and rate.