Abstract:
A method for actuating plural sets of vibratory seismic sources. The method includes calculating, at a controller, a continuous signal Cn that is made as a periodic repetition of a template pn, wherein the template pn includes a swept-frequency signal; receiving a subset duration time Lsub; receiving a tapering function W having a time length of Lsub; receiving a calendar time tsweep; computing, at the controller, a product Sn of a subset of the continuous signal Cn and the tapering function W, wherein the subset of the continuous signal Cn starts at the calendar time tsweep and lasts for the duration time Lsub; and actuating a set n of the plural sets of vibratory sources at the calendar time tsweep, wherein each vibratory source of the set n of vibratory sources is actuated based on the product Sn.
Abstract:
Methods for seismic exploration of a subsurface formation increase productivity by simultaneously actuating closely located vibratory sources. Individual vibrations generated by different sources actuated simultaneously are encoded to enable separation of seismic data corresponding to each of the individual vibrations.
Abstract:
An electric sweep type seismic vibrator source of the type used in seismic prospecting for hydrocarbons is provided. In one example, the source uses an engine and generator combination to create electric power for all systems on the source such as driving a frame of linear electric motors that direct a rod or piston to contact the ground in a recurring fashion along with driving the source from location to location through a survey area. A foot is arranged on the bottom end of the rod or piston for contact with the ground and by engaging the grid of motors to push down against the ground in a rapid progression, acoustic energy is created and delivered into the ground for geophones to sense and record.
Abstract:
The invention is an electric sweep type seismic vibrator source of the type used in seismic prospecting for hydrocarbons. The source uses an engine and generator combination to create electric power for all systems on the source such as driving a frame of linear electric motors that direct a rod or piston to contact the ground in a recurring fashion along with driving the source from location to location through a survey area. Preferably a foot is arranged on the bottom end of the rod or piston for contact with the ground and by engaging the grid of motors to push down against the ground to create impulses that deliver acoustic seismic energy into the earth for geophones to sense and record. However, the pulses of seismic energy are delivered in a distinctive fashion where different linear motors are deliberately and concurrently providing different signals that create a distinctive composite signature or signal that can be identified in the data record for source separation purpose.
Abstract:
The invention is an electric power accumulator used with an electric sweep type seismic vibrator source of the type used in seismic prospecting for hydrocarbons. The source uses an engine and generator combination to create electric power to drive a frame of linear electric motors that direct a rod or piston to contact the ground in a recurring fashion. The source may also be designed to use electric power to drive the source from location to location through a survey area. A large electric power accumulator is provided to store electric power when the generator is able to produce excess power and the accumulator may deliver power along with the generator to drive the rods and deliver acoustic energy. With a large electric power accumulator, such as a battery or capacitor, the engine and generator combination may be engineered to be somewhat smaller, less costly and more efficient than a system where the engine and generator were sized to provide the electric power at times of maximum electric draw.
Abstract:
A deployment and retrieval apparatus for ocean bottom seismic receivers, the apparatus being a remotely operated vehicle (ROV) having a carrier attached thereto and carrying a plurality of receivers. The carrier includes a frame in which is mounted a structure for seating and releasing the receivers. The structure may include a movable conveyor or fixed parallel rails or a barrel. The structure includes a discharge port on the frame and a discharge mechanism for removing and retrieving the receivers. A method for deployment and retrieval of ocean bottom seismic receivers includes the steps of loading a carrier with a plurality of receivers, attaching the carrier to an ROV, utilizing the ROV to transport the carrier from a surface vessel to a position adjacent the seabed and thereafter utilizing the ROV to remove receivers from the carrier and place the receivers on the seabed.
Abstract:
A method and apparatus for storing, transporting, and transferring one or more sensor devices is described. In one embodiment, the apparatus includes a transfer device having a frame, and a movable platform coupled to the frame. A mesh material may be coupled to the frame and surround at least one side of the movable platform and a mating interface is formed in a side of the frame that is adapted to couple with a remotely operated vehicle in an underwater location.
Abstract:
An apparatus and method is provided for transporting, installing, retrieving, and replacing a sensor array of individual sensor pods at a geographically remote location, such as on the sea floor. The apparatus consists of a remotely operated vehicle (ROV), a carousel attached to the ROV, a pod ejector mechanism attached to the carousel, and a manipulator with a manipulator end effector attached to the ROV. The carousel contains a plurality of sensor pod holders, where each sensor pod holder is capable of holding a sensor pod. The pod ejector mechanism is capable of discharging a fresh sensor pod, while the manipulator end effector is capable of lifting a depleted sensor pod and placing the depleted sensor pod in an empty sensor pod holder in the carousel.
Abstract:
Two tracks are mounted between a vibratory source of shear, or horizontally travelling, wave siesmic energy and its transport vehicle. The tracks are parallel to each other in the direction of horizontal movement of the source when vibrating. One track is attached to the source, and the other to the vehicle. Pressurized rounded resilient members, which may be either spherical bags or wide tires, are mounted between the tracks to isolate the vehicle from vibrations, insuring that the seismic energy enters the earth.
Abstract:
A transportable hydraulic seismic transducer has a seismic energy source connected to a pad for imparting elastic waves to the underlying ground. The energy source has a reaction mass with a single diameter cylinder formed therein, a double ended piston reciprocally mounted in the cylinder with a piston rod extending from opposite ends of the piston and a pair of bushings fitted within the cylinder at opposite ends to provide bearing surfaces for the opposite ends of the piston rod. A piston may be ringed and a liner fitted into place within the cylinder with the rings forming a seal with the liner. The piston may also be ringless and a liner made of a bushing material fitted within the cylinder so that between the piston and the liner, an adequate seal is provided. The use of the single diameter cylinder or bore permits the total machining of inserted parts such as the bushings and liners to be done before inserting in the reaction mass bore.