Abstract:
A method for determining position of a wellbore in the Earth's subsurface includes actuating a plurality of seismic energy sources each disposed at a known geodetic position. Seismic energy from the sources is detected at a selected location along the wellbore. The geodetic position at the selected location is determined from the detected seismic energy. A corresponding method includes actuating a seismic energy source at a selected position within the wellbore. The seismic energy is detected at a plurality of known geodetic positions. The geodetic position of the source is determined from the detected seismic energy.
Abstract:
Method for operating and testing a sensor assembly (210). The sensor assembly (210) preferably includes accelerometers with axes of sensitivity orthogonal to each other. The method preferably includes determining sensor tilt angle, determining the position of the sensor, and synchronizing the operation of the sensor.
Abstract:
An energy source for shear wave within the surface of the earth. The energy source has a convoluted shape (405). In a preferred embodiment, the pitch of the spacing (425) of the flexible explosive material (405) and the flexible transfer material (430) around the tube (410) ranges from about 20 to 45 degrees relative to the horizontal direction in order to optionally excite a range of frequencies.
Abstract:
The present invention relates to a harmonic seismic wave generator which continuously generates seismic waves with a single precisely defined frequency and amplitude and with a special radiation characteristic. The invention further relates to an assembly useful for seismic prospecting and a method of seismic prospecting. A signal generated by the generator propagates through the rock environment, is received by an array of the seismic stations and is processed in a way that detects and analyzes nonlinear phenomena in the propagation of seismic waves. The use of the generator allows, in particular, a detection of critical stress before an earthquake.
Abstract:
Shear wave generator for use subsea, comprising: an excitation unit (1) that is fastened to a top plate (2); a skirt (3) that at an upper end (3a) is fastened sealingly to the top plate and extending downward to an open lower end (3b) of the skirt, such that the top plate and skirt form a closed space by lowering to the seabed; and a pump (5) arranged with fluid communication between said space and the surroundings, such that by pumping water out of said space underpressure is formed acting to suck the shear wave generator fixedly to and partly into the seabed, and by pumping water into said space overpressure is formed acting to lift the shear wave generator up from the seabed. The shear wave generator is distinguished in that the skirt (3) is formed with larger outer diameter or width at its upper end than at its lower end.
Abstract:
A system and method for utilizing a surface located oscillator (15) to generate seismic signals at a downhole location. The system includes a vibratory source (15) for generating axial vibrational energy in a tubular string (40) anchored in the borehole (55) at a suitable location. The vibratory source may be operated at a predetermined frequency or may generate a swept frequency signal. The axial vibrations are transmitted through the tubular string (40) and impart a seismic signal through the anchor (50) to the formation. In different configurations, the system imparts broadband seismic signals into the formation. Sensors (20, 21, 22, 45) are mounted on the vibratory source and downhole anchor for monitoring the system operation. Seismic receivers (70a, 70n, 80a, 80n, 90a, 90n) are deployed on the surface, in offset wells, or in the source well. Signals from the receivers are transmitted to a control unit (25). The control unit utilizes the sensor and receiver signals to control the operation of the vibratory source.
Abstract:
A system for resiliently attaching a mass to a package includes a mass (104), a housing (102), resilient couplings (108) for resiliently attaching the mass to the housing.
Abstract:
Improved methods of gather high fidelity vibratory seismic surveys for ZenSeis® systems wherein at least one optimal phase encoding schemes for surveys having 2-8 vibratory sources are disclosed. These encoding schemes can be hard coded into the source controller and will allow for quality data to be obtained on each survey. Further, the data will also have the best separation during inversion processing steps, leading to an optimal seismic survey.
Abstract:
A method for performing a seismic survey using at least one carrier (2) which includes a seismic source (8). The method including: deploying each of the at least one carriers by the delivery vehicle (4), wherein each of the at least one carriers includes: a plurality of supports (126) configured to enable a baseplate (124) to contact ground, wherein the baseplate is formed by each foot of the plurality of supports; a seismic source which includes a lower portion configured to push through unconsolidated materials and configured to contact the ground; and a power source (100) configured to operate the seismic source; and transmitting at least one seismic signal from the seismic source.
Abstract:
Node, system and method for collecting seismic data. A node (300) for collecting seismic data includes a base (302) configured to land on the ocean floor; and a head (304) connected to the base (302) through a connecting member (306) and configured to bury itself into the ocean floor. The head (304) includes a seismic sensor (334a) configured to detect seismic data and first to third burying units (450A- C) configured to bury the head (304).