摘要:
A technique facilitates the reduction of seismic source signature variation during a seismic survey. The technique involves estimating an azimuth angle and/or a departure angle for one or more seismic source elements. The angles are used to determine adjustments, such as seismic source depth adjustments, able to reduce seismic source signature variation. The adjustments can be made prior to firing the one or more seismic source elements.
摘要:
The presently disclosed technique includes a method for use in a marine survey comprising randomizing the distribution of receivers and sources during a coil shoot acquisition. The randomizing can be implemented in a number of ways. For example, in one embodiment, randomizing the distribution includes randomizing the positions of the circle centers defining the sail lines. This may be implemented by, for example, distributing the same number of circle centers as would be used in a non-random sampling in a uniform random distribution. In another embodiment, randomizing the distribution includes permitting the streamers in which the receivers are allowed to drift while controlling crossline streamer separation. Other embodiments may combine these approaches or utilize still other approaches.
摘要:
A method for acquiring seismic data. The method may include towing one or more seismic streamers in the water, towing a first air gun array and a second air gun array in the water at a first depth, and towing a third air gun array and a fourth air gun array in the water at a second depth greater than the first depth. While towing the air gun arrays, the first and second air gun arrays and the third and fourth air gun arrays may be separated by a cross line distance that depends on a separation between the seismic streamers. The method may also include firing seismic energy, by the first, second, third and fourth air gun arrays, through the water into the earth. After firing the seismic energy, the method may record seismic signals reflected from strata in the earth beneath the water.
摘要:
A method and apparatus for acquiring seismic data. In one embodiment, the method includes: moving a first air gun array in the water at a first depth and a second air gun array in the water at a second depth greater than the first depth, in which the total volume of the first air gun array is less than the total volume of the second air gun array, in which the first air gun array is separated from the second air gun array by a distance substantially equal to a shot point interval, firing seismic energy through the first and second air gun arrays through the water into the earth, and recording seismic signals reflected from strata in the earth beneath the water.
摘要:
A method is described that attenuates reverberations in ocean bottom cable data used to generate a seismic profile. First, a seismic wave is generated and recorded by pressure and particle velocity sensor pairs. Adding the product of the pressure data times the absolute value of the velocity data and the product of the velocity data times the absolute value of the pressure data eliminates reverberations, leaving a combined signal that is a function of only the primary wave response signal. Dividing this combined signal by the number 2 and a sensitivity scaling factor, and then taking the square root of the result produces the magnitude of the primary signal. Replacing the positive/negative sign of the combined signal that existed before taking the absolute value provides the proper polarity. The data are then incorporated into a seismic profile.
摘要:
Methods to attenuating strong marine seismic noises using singular value decomposition, determining noisiest traces and estimating noise components only from these traces, iteratively estimating the noise and protecting signal behind the noise. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).
摘要:
A technique for use in marine seismic surveying includes a method and an apparatus. In one aspect, the method includes towing a seismic spread including a source multiple streamers on a generally curved advancing path, the streamers being actively steered. The source is fired and data is acquired on the curve. In other aspects, the method is performed with only a single vessel or the generally curved advancing path is a sincurve advancing path. The method may include a dual circular shoot in another aspect. And, in yet another aspect, the invention includes an apparatus comprised of a computing apparatus on board a tow vessel receiving positioning data from the marine seismic streamers. It is also programmed to: sail the tow vessel in a generally curved advancing path and actively steer the marine seismic streamers through the generally curved advancing path.
摘要:
A method and apparatus for acquiring seismic signals from beneath a salt region in the earth. In one embodiment, the method includes tuning an air gun array to a first bubble oscillation; towing the air gun array in the water at a depth of at least 10 meters, in which the air gun array has a total volume in a range of about 6780 cubic inches to about 10,170 cubic inches; directing acoustic signals with the air gun array down through the water into the earth beneath the salt region; towing one or more seismic streamers in the water at one or more depths, in which at least one of the depths is at least 10 meters, in which each streamer comprises a plurality of hydrophones disposed therealong; and recording with the hydrophones seismic signals reflected from strata in the earth beneath the salt region.
摘要:
A subterranean structure is characterized using composite seismic response data received from a plurality of sources. Phase encoding is applied to the data in which phase shifts are selected based on frequency variation of noise terms. The phase-encoded data is then migrated and a representation of the subterranean structure is produced according to the migrating.
摘要:
Systems and methods for determining object location may include a memory and a processor. The processor may be configured to collect seismic data and geophysical data to determine object location. The processor may be configured to determine one or more seismic attributes associated with a plurality types of noises based on the seismic data and the geophysical data using one or more machine learning algorithms. The processor may be configured to eliminate unwanted noises from noise classifications based on the one or more seismic attributes. The processor may be configured to predict the object location by comparing time and velocity data of the object with recorded timing and velocity data. The processor may be configured to validate the object location by comparing the determined noise with image data. The systems and methods may be used in, for example, detecting missing planes such as Malaysian Airlines Flight 370.