摘要:
A dipole source for borehole acoustic logging includes a cylindrical shell, a center beam coupled to the cylindrical shell, a movable projector inside the cylindrical shell to impact the center beam, and a cavity acoustically insulating the interior of the cylindrical shell from the exterior of the cylindrical shell. An acoustic logging tool for making measurements of a substrate surrounding a borehole with a body insertable in the borehole is also provided. The body includes an acoustic detector and a dipole source as above, along the axial length. The acoustic logging tool may include a control unit to process data collected from the acoustic detector and obtain information about the substrate surrounding the borehole.
摘要:
Method, source and shuttle configured to generate acoustic waves under water. The shuttle includes a firing piston closing a firing chamber and contributing to holding the compressed gas, and a transitional region connected to the firing piston. The firing chamber and the transitional region define a most restrictive area through which the compressed gas is released toward the at least one exhaust port, the most restrictive area is substantially smooth while the movable shuttle moves toward the open position, and a profile of the transitional region is selected to reduce a high-frequency content of the acoustic waves.
摘要:
A method of performing a seismic sweep includes forming a composite force profile; constructing a target seismic frequency sweep using the composite force profile; and operating a seismic source using the constructed target frequency seismic sweep.
摘要:
A seismic energy source includes a base plate and a block fixedly coupled in a frame. The base plate is configured for contact with a part of the Earth's subsurface to be seismically energized. The frame has a first electromagnet associated therewith. A second electromagnet is disposed in a travelling reaction mass, which is movably disposed in the frame between the first electromagnet assembly and the top block. The reaction mass includes at least a third electromagnet associated therewith. The source has circuits for selectively energizing the first, second and at least a third electromagnets, and which are configured to energize the first and second electromagnets to repel each other such that the traveling reaction mass is lifted from the first electromagnet, and configured to energize the at least a third electromagnet after a selected delay time to cause attraction between the traveling reaction mass and the top block
摘要:
The present invention provides an accelerated weight drop for use as a seismic energy source, a method for operating an accelerated weight drop for use as a seismic energy source, and a seismic survey system including the accelerated weight drop. The accelerated weight drop, among other elements, may include a striker positionable over a surface, a compressed gas spring configured to drive the striker toward the surface thus creating seismic waves within the surface, and a cushioning means positioned proximate the compressed gas spring for dissipating reflected energy. In this embodiment the striker is slidably coupled to the compressed gas spring.
摘要:
In a bore holes, a plurality of resilient members and plates are piled up alternately to form a laminate, and a deadweight is dropped onto the laminate. The resilient members are deformed due to the impact force of the dropped deadweight to cause bore hole water among the plates to be forced out in the outward direction, and elastic waves to occur in the bore hole wall.
摘要:
A method and an apparatus for mass retrieval for an acoustic pulse generator are disclosed herein. In an impulse type seismic generating apparatus an air spring, mechanical spring, controlled pressurization of an air spring or other energy storage medium is employed to use potential energy to raise the impact mass to a resting position above an earth contacting baseplate as quickly as possible after the impact mass strikes the baseplate.
摘要:
An anti-bounce device for a mass striking a target element, with the device including a counter mass and a linking arrangement for holding the counter mass spaced from the mass and a braking arrangement for delaying the counter mass so as to put the counter mass in phase opposition with the mass as the mass bounces after impact thereby dissipating any bouncing force. The linking arrangement may take the form of a volume of fluid in a chamber provided between the mass and counter mass, and the linking arrangement and braking arrangement may also include a layer of a damping material or deformable or flexible elements acting by friction.
摘要:
Alignment restoring apparatus for use with seismic shock generators that includes a support frame, a lift frame supported by the support frame, a seismic generator peripherally supported by the lift frame, and a base plate supported by the life frame and arranged to be impacted by the seismic generator. The alignment restoring apparatus includes biasing means located between the lift frame and the base plate to provide a restoring force upon movement of the frame relative to the base plate whereby the initial relationship between the frame and base plate is re-established assuring that the time lapse from initiating the propulsion of the seismic generator toward the base plate to the time of impact therebetween is repeatable.
摘要:
An impulsive seismic generator is mounted on a swamp buggy suitable for operations both in a marshy environment and on land. The generator employs a target plate which may be lowered into a body of water or mud beneath the buggy so as to contact subsurfaces of varying degrees of firmness. The submerged components of the generator are surrounded by a water-tight barrier which isolates the space between a descending mass and the receiving target plate from the surrounding fluid.