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4578784 Tunable marine seismic source
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New Patents
In marine seismic exploration, seismic energy is transmitted through a water layer into the earth and seismic reflection signals from subsurface interfaces are recorded. Any undulating water bottom distortion in the recorded reflection signals is removed by replacing the seismic energy velocity in the water layer with a velocity matching that of the earth medium below the water bottom.
lstream fluids in the pipeline warm to a temperature outside the range where hydrates may form.
4578784
Mitsuhiro Yazaki, Kakogawa, Japan assigned to Kawasaki Jukogyo Kabushiki Kaisha
TUNABLE MARINE SOURCE
SEISMIC
Joseph F Mi~ud assigned to Exxon Production Resea~h Co 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 oleopneumatic 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.
4590798 APPARATUS FOR DETECTING OIL LEVEL IN OIL TANK OF SMALL-SIZED MARINE CRAFT
An apparatus for detecting the oil level in an oil tank of a marine craft. The fuel inlet of a fuel tank which is disposed within a craft body is provided outside of the craft body in an exposed state. The oil tank is arranged adjacently to the fuel tank, and an oil level detecting means for this oil tank is arranged adjacently to the fuel inlet such as to allow the oil level to be directly observed from the outside of the craft body.
4~3~5 FIBER OPTIC SENSOR LEAD FIBER NOISE CANCELLATION Jacques R Chamuel assigned to The Charles Stark Draper Laboratory
4~94M METHOD AND APPARATUS TO PREVENT HYDRATE FORMATION IN FULL WELLSTREAM PIPELINES Bruce T Kelley assigned to Exxon Production Research Co 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 wel-
An optoacoustic hydrophone for detection of acoustic waves in a fluid such as sea water. The hydrophone includes an optical waveguide comprising a fiber optic input lead, a fiber optic sensor, and a fiber optic exit lead, an optical subassembly and a signal processor. A coherent light beam generated by the optical subassembly is transmitted through the input lead and the sensor which is disposed in the fluid. Acoustic waves in the fluid modulate the index of refraction of the fiber optic sensor thereby modulating the transmitted light beam. The modulated light beam is directed through the fiber optic exit lead to a focus on one of two photo ~etectors. The other photodetector is oriented for receipt of light reflected from a partially reflective mirror disposed between the input fiber optic lead and the fiber optic sensor. The two light beams impinging on respective photodetector are combined with unmodulated light beams of slightly different frequencies to produce an interference pattern at each photodetector. Each photodetectors produces an electrical signal representative of the interference pattern and the respective electrical signals are applied to a phase meter. The phase meter produces an output
New Patents
In marine seismic exploration, seismic energy is transmitted through a water layer into the earth and seismic reflection signals from subsurface interfaces are recorded. Any undulating water bottom distortion in the recorded reflection signals is removed by replacing the seismic energy velocity in the water layer with a velocity matching that of the earth medium below the water bottom.
lstream fluids in the pipeline warm to a temperature outside the range where hydrates may form.
4578784
Mitsuhiro Yazaki, Kakogawa, Japan assigned to Kawasaki Jukogyo Kabushiki Kaisha
TUNABLE MARINE SOURCE
SEISMIC
Joseph F Mi~ud assigned to Exxon Production Resea~h Co 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 oleopneumatic 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.
4590798 APPARATUS FOR DETECTING OIL LEVEL IN OIL TANK OF SMALL-SIZED MARINE CRAFT
An apparatus for detecting the oil level in an oil tank of a marine craft. The fuel inlet of a fuel tank which is disposed within a craft body is provided outside of the craft body in an exposed state. The oil tank is arranged adjacently to the fuel tank, and an oil level detecting means for this oil tank is arranged adjacently to the fuel inlet such as to allow the oil level to be directly observed from the outside of the craft body.
4~3~5 FIBER OPTIC SENSOR LEAD FIBER NOISE CANCELLATION Jacques R Chamuel assigned to The Charles Stark Draper Laboratory
4~94M METHOD AND APPARATUS TO PREVENT HYDRATE FORMATION IN FULL WELLSTREAM PIPELINES Bruce T Kelley assigned to Exxon Production Research Co 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 wel-
An optoacoustic hydrophone for detection of acoustic waves in a fluid such as sea water. The hydrophone includes an optical waveguide comprising a fiber optic input lead, a fiber optic sensor, and a fiber optic exit lead, an optical subassembly and a signal processor. A coherent light beam generated by the optical subassembly is transmitted through the input lead and the sensor which is disposed in the fluid. Acoustic waves in the fluid modulate the index of refraction of the fiber optic sensor thereby modulating the transmitted light beam. The modulated light beam is directed through the fiber optic exit lead to a focus on one of two photo ~etectors. The other photodetector is oriented for receipt of light reflected from a partially reflective mirror disposed between the input fiber optic lead and the fiber optic sensor. The two light beams impinging on respective photodetector are combined with unmodulated light beams of slightly different frequencies to produce an interference pattern at each photodetector. Each photodetectors produces an electrical signal representative of the interference pattern and the respective electrical signals are applied to a phase meter. The phase meter produces an output