Abstract:
The liquid slug projector apparatus is entirely pneumatically operated. It comprises a generator having a main housing whose main port fluidly communicates with a liquid body. A first shuttle and a second shuttle are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber for confining therein a liquid slug. A pneumatic source together with a pneumatically-operated valve cyclically cause the shuttles to move relative to or in locked condition with each other, thereby applying during each cycle of operation an abrupt propulsion force to the confined liquid slug which becomes expelled as a very high-velocity liquid jet through the main port.
Abstract:
A method of seismic exploration and a system which provides the capability for increasing the number of depth points from which seismic data are acquired are disclosed. This increase in data is realized without increasing the number of recording channels or the number of geophone stations employed in the system. A higher common depth point multiplicity is achieved by separating energy sources in relation to geophone stations. The recording system is capable of automatically sorting out the data from different energy sources and storing it in different blocks of a memory. Since substantially all available recording time is fully utilized by using energy sources to their optimum efficiency, higher common-depth-point multiplicity can be achieved with minimum field costs.
Abstract:
In generating seismic waves in earth a generator having a generally elongate, tubular expandable and contractible outer wall portion closed at its upper and lower ends by rigid strength members having separate input and return pressure lines is placed in a well bore, a hydraulic coupling pressure is applied through the input line which causes the expandable wall portion to engage and remain coupled with and in direct contact with the earth wall in the well bore and hydraulic pressure impulses are then cycled through the input and return lines at pressures greater than the coupling pressure to cause further expansion of the expandable wall portion, thereby generating and radiating seismic waves in the earth upon application of each impulse while maintaining the hydraulic coupling pressure sufficient to effectively maintain the outer wall anchored to the wall of the bore hole. The coupling pressure should be sufficient to anchor and couple the transducer to the well bore without any additional anchoring. The pressure impulses should be sufficiently higher than the coupling pressure to create motion in the earth within the earth's elastic range. In marsh or marine waters, the coupling pressure is omitted and the generator is placed in the water above the earth.
Abstract:
A mobile generator for producing waves for seismic exploration. An elongated boom guides a wave-generating hammer along a linear path of motion to strike an anvil embedded in the ground, the boom being movable between several adjusted positions including a vertical position for generating a P wave, an inclined position for generating a shear wave, and a horizontal position for transport. An improved anvil for generating either a P wave or a shear wave is also disclosed.
Abstract:
An improved base plate for a vibratory seismic signal generator consists of a plurality of parallel T-bars welded together. The flange of every adjacent T-bar is inverted with respect to its neighbors.
Abstract:
A vibratory seismic energy source capable of generating significant energy over a broad frequency band. The vibrating baseplate and associated structure are designed to have minimum weight while still retaining sufficient structural integrity to permit the use of high actuator forces. This, coupled with a large reaction mass results in the generation of significant energy levels in the earth at high frequencies.
Abstract:
Method and apparatus are provided for generating in situ in a zone of earth surrounding a bore hole both longitudinal and shear waves and of predetermined relative amplitude, entirely mechanically, avoiding use of explosives, and with relatively low power requirements for the stress waves generated. Subterranean impacts generating high amplitude stress waves equivalent to those generated by fifteen pounds of TNT or multiples of such quantities of TNT are realized. These high amplitude waves are produced in an annular zone ten feet or more from the earth bore, where the earth specimen has not been previously disturbed and its measured properties are therefore truly representative of the medium. In addition to being a non-explosive earth stress wave generator, the present device, and method herein, enables controllable variation in the amplitude of the shear wave relative to the longitudinal wave and vice versa by control of operating parameters using the same equipment, including rate of rotation, travel distance and mass/area relationship.
Abstract:
A seismic signal is generated having a pattern which is periodically repetitive. The signal within each period has a nonrepetitive pattern and each period has a time duration not less than the time required for the seismic wave to travel to the deepest subsurface strata of interest and back to the detecting location.
Abstract:
A signal is transmitted through the walls of tubing extending down into an oil well in order to control a disaster valve at the lower end of the tubing. If the signal disappears, the valve shuts. In one embodiment, the tubing functions as the core of a transformer. In another embodiment, the tubing conducts an acoustic signal.
Abstract:
Apparatus for activating a seismic explosive charge includes a communications link for permitting two-way communication between a control location and a seismic energy generator or explosive charge location, first and second code generators respectively at the control location and the generator location, and first and second code detectors respectively at the control location and the generator location. A code group is transmitted from the control location to the generator location. Upon being detected at the generator location, the code group is retransmitted back to the control location and simultaneously the code group is again detected at the generator location so as to concomitantly produce detection signals at both the generator location and the control location. At the generator location the detection signal is used to activate the seismic explosive charge and at the control location to generate a time break electrical signal. The first arrivals of seismic energy at a location on the earth''s surface substantially vertically above the explosive charge is detected. A counter at the generator location, which is reset whenever a detection signal is generated at the generator location, measures the time interval from the activation of the seismic charge to the detection of the first arrivals. A binary signal indicative of the time interval is transmitted back to the control location where it is recorded or otherwise utilized.