Seismic surveys with optical communication links
First Claim
1. A system to perform a seismic survey in a marine environment, comprising:
- a seismic data acquisition unit placed on a seabed in the marine environment, the seismic data acquisition unit including a first clock;
an extraction vehicle to establish an optical communications link with the seismic data acquisition unit, the extraction vehicle including a second clock, a transmitter, and a data processing system to;
transmit, via the transmitter, to the seismic data acquisition unit, a reference pulse based on the second clock;
syntonize, via the optical communications link, based on the transmitted reference pulse, a frequency of the first clock of the seismic data acquisition unit to a frequency of the second clock prior to the seismic data acquisition unit entering a low power state;
receive a signal generated by the first clock from the seismic data acquisition unit responsive to syntonization of the frequency of the first clock to the frequency of the second clock, the signal indicating that the frequency of the first clock is syntonized with the frequency of the second clock;
instruct the seismic data acquisition unit to enter the low power state responsive to receipt of the signal from the seismic data acquisition unit, the seismic data acquisition unit configured to exit the low power state and acquire seismic data in an operational state;
receive, from the seismic data acquisition unit, the seismic data acquired by the seismic data acquisition unit in the operational state;
measure a timing variation of a plurality of timestamps of the seismic data applied by the first clock in response to the seismic data received from the seismic data acquisition unit;
produce a time variation function based on the measured timing variation, the time variation function configured to indicate a time offset and a frequency offset between the first clock and the second clock; and
adjust the seismic data comprising the plurality of timestamps applied by the first clock using the time variation function to remove timing errors from the seismic data.
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Accused Products
Abstract
Systems and methods of optical link communication with seismic data acquisition units are provided. The systems and methods can perform at least portions of seismic data acquisition survey. A plurality of seismic data acquisition units can be deployed on a seabed. An optical communications link can be established between an extraction vehicle and at least one of the seismic data acquisition units. A frequency of the at least one seismic data acquisition unit can be syntonized or synchronized via the optical communications link. The at least one seismic data acquisition unit can be instructed to enter a low power state subsequent to syntonizing the frequency of the at least one seismic data acquisition unit. The seismic data acquisition unit can exit the low power state and acquire seismic data in an operational state.
184 Citations
19 Claims
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1. A system to perform a seismic survey in a marine environment, comprising:
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a seismic data acquisition unit placed on a seabed in the marine environment, the seismic data acquisition unit including a first clock; an extraction vehicle to establish an optical communications link with the seismic data acquisition unit, the extraction vehicle including a second clock, a transmitter, and a data processing system to; transmit, via the transmitter, to the seismic data acquisition unit, a reference pulse based on the second clock; syntonize, via the optical communications link, based on the transmitted reference pulse, a frequency of the first clock of the seismic data acquisition unit to a frequency of the second clock prior to the seismic data acquisition unit entering a low power state; receive a signal generated by the first clock from the seismic data acquisition unit responsive to syntonization of the frequency of the first clock to the frequency of the second clock, the signal indicating that the frequency of the first clock is syntonized with the frequency of the second clock; instruct the seismic data acquisition unit to enter the low power state responsive to receipt of the signal from the seismic data acquisition unit, the seismic data acquisition unit configured to exit the low power state and acquire seismic data in an operational state; receive, from the seismic data acquisition unit, the seismic data acquired by the seismic data acquisition unit in the operational state; measure a timing variation of a plurality of timestamps of the seismic data applied by the first clock in response to the seismic data received from the seismic data acquisition unit; produce a time variation function based on the measured timing variation, the time variation function configured to indicate a time offset and a frequency offset between the first clock and the second clock; and adjust the seismic data comprising the plurality of timestamps applied by the first clock using the time variation function to remove timing errors from the seismic data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of performing a seismic survey in a marine environment, comprising:
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positioning a seismic data acquisition unit on a seabed in the marine environment, the seismic data acquisition unit including a first clock; establishing, by an extraction vehicle, an optical communications link with the seismic data acquisition unit, the extraction vehicle including a second clock, a transmitter, and a data processing system; transmitting, by the data processing system, via the transmitter, a reference pulse based on the second clock; syntonizing, by the data processing system, via the optical communications link, based on the transmitted reference pulse, the first clock of the seismic data acquisition unit to correspond to the second clock prior to the seismic data acquisition unit entering a low power state; receiving, responsive to syntonization of the frequency of the first clock to the frequency of the second clock, a signal generated by the first clock from the seismic data acquisition unit, the signal indicating that the frequency of the first clock is syntonized with the frequency of the second clock; instructing, by the data processing system, the seismic data acquisition unit to enter the low power state responsive to receipt of the signal from the seismic data acquisition unit, wherein the seismic data acquisition unit is configured to exit the low power state and acquire seismic data in an operational state; receiving, by the data processing system, from the seismic data acquisition unit, the seismic data acquired by the seismic data acquisition unit in the operational state; measuring, by the data processing system, a timing variation of a plurality of timestamps of the seismic data applied by the first clock in response to the seismic data received from the seismic data acquisition unit; producing, by the data processing system, a time variation function based on the measured timing variation, the time variation function configured to indicate a time offset and a frequency offset between the first clock and the second clock; and adjusting, by the data processing system, the seismic data comprising the plurality of timestamps applied by the first clock using the time variation function to remove timing errors from the seismic data. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification