HIGH-PRODUCTIVITY SEISMIC DATA ACQUISITION USING CALENDAR-TIME-BASED SWEEP INITIATION
A method for actuating plural sets of vibratory seismic sources. The method includes calculating, at a controller, a continuous signal C n that is made as a periodic repetition of a template p n , wherein the template p n includes a swept-frequency signal; receiving a subset duration time L sub ; receiving a tapering function W having a time length of L sub ; receiving a calendar time t sweep ; computing, at the controller, a product S n of a subset of the continuous signal C n and the tapering function W, wherein the subset of the continuous signal C n starts at the calendar time t sweep and lasts for the duration time L sub ; and actuating a set n of the plural sets of vibratory sources at the calendar time t sweep , wherein each vibratory source of the set n of vibratory sources is actuated based on the product S n .
1 . A method for actuating plural sets of vibratory seismic sources, the method comprising:
calculating, at a controller, a continuous signal C n that is made as a periodic repetition of a template p n , wherein the template p n includes a swept-frequency signal;
receiving a subset duration time L sub ;
receiving a tapering function W having a time length of L sub ;
receiving a calendar time t sweep ;
computing, at the controller, a product S n of a subset of the continuous signal C n and the tapering function W, wherein the subset of the continuous signal C n starts at the calendar time t sweep and lasts for the duration time L sub ; and
actuating a set n of the plural sets of vibratory sources at the calendar time t sweep , wherein each vibratory source of the set n of vibratory sources is actuated based on the product S n .
2 . The method of claim 1 , further comprising:
calculating a continuous signal C n for each set n of the plural vibratory sources.
3 . The method of claim 2 , wherein each continuous signal C n has a corresponding sweep s n having a corresponding time length L SWn , amplitude profile A n , frequency profile f n , initial phase Φ n and tapering function Tap n .
4 . The method of claim 3 , further comprising:
receiving N slip-times T slipn , wherein the slip-time T slipn is a time delay between a starting time of a first set of vibratory sources and a starting time of the n set of vibratory sources.
5 . The method of claim 3 , further comprising:
calculating the subset duration time L P as a sum of all N slip-time T slipn .
6 . The method of claim 4 , further comprising:
calculating the template p n as a sum of a swept frequency signal s n and a taper time.
7 . The method of claim 6 , further comprising:
calculating a time shift τ n as a sum of all N slip-time T slipn ; and
computing the continuous signal C n by periodically repeating the template p n from the time shift τ n .
8 . The method of claim 1 , wherein the template p n is made of the swept-frequency signal followed by a waiting time.
9 . The method of claim 3 , wherein the sweep length L SWn is a time interval during which a vibratory source emits a given set of frequencies, a starting frequency of the sweep length being f s and an end frequency of the sweep length being f e , the record length L R is a time during which seismic sensors record seismic signals originating from the vibratory source, and a taper function makes a smooth transition at the start and end frequencies.
10 . A controller for actuating plural sets of vibratory seismic sources, the controller comprising:
an interface for
receiving a subset duration time L sub ,
receiving a tapering function W having a time length of L sub , and
receiving a calendar time t sweep ; and
a processor connected to the interface and configured to,
calculate a continuous signal C n that is made as a periodic repetition of a template p n , wherein the template p n includes a swept-frequency signal,
compute a product S n of a subset of the continuous signal C n and the tapering function W, wherein the subset of the continuous signal C n starts at the calendar time t sweep and lasts for the duration time L sub , and
actuate a set n of the plural sets of vibratory sources at the calendar time t sweep , wherein each vibratory source of the set n of vibratory sources is actuated based on the product S n .
11 . The controller of claim 10 , wherein the processor is further configured to:
calculate a continuous signal C n for each set n of the plural vibratory sources.
12 . The controller of claim 11 , wherein each continuous signal C n has a corresponding sweep s n having a corresponding time length L SWn , amplitude profile A n , frequency profile f n , initial phase Φ n and tapering function Tap n .
13 . The controller of claim 12 , wherein the interface is configured to:
receive N slip-times T slipn , wherein the slip-time T slipn is a time delay between a starting time of a first set of vibratory sources and a starting time of the n set of vibratory sources.
14 . The controller of claim 12 , wherein the processor is configured to:
calculate the subset duration time L P as a sum of all N slip-time T slipn .
15 . The controller of claim 13 , wherein the processor is configured to:
calculate the template p n as a sum of a swept frequency signal s n and a taper time.
16 . The controller of claim 15 , wherein the processor is configured to:
calculate a time shift τ n as a sum of all N slip-time T slipn ; and
compute the continuous signal C n by periodically repeating the template p n from the time shift τ n .
17 . The controller of claim 10 , wherein the template p n is made of the swept-frequency signal followed by a waiting time.
18 . The controller of claim 12 , wherein the sweep length L SWn is a time interval during which a vibratory source emits a given set of frequencies, a starting frequency of the sweep length being f s and an end frequency of the sweep length being f e , the record length L R is a time during which seismic sensors record seismic signals originating from the vibratory source, and a taper function makes a smooth transition at the start and end frequencies.
19 . A system for actuating plural sets of vibratory seismic sources, the system comprising:
a land seismic carrier configured to move with a seismic source; and
a controller located on the land seismic carrier,
wherein the controller includes,
an interface for
receiving a subset duration time L sub ,
receiving a tapering function W having a time length of L sub , and
receiving a calendar time t sweep ; and
a processor connected to the interface and configured to,
calculate a continuous signal C n that is made as a periodic repetition of a template p n , wherein the template p n includes a swept-frequency signal,
compute a product S n of a subset of the continuous signal C n and the tapering function W, wherein the subset of the continuous signal C n starts at the calendar time t sweep and lasts for the duration time L sub , and
actuate a set n of the plural sets of vibratory sources at the calendar time t sweep , wherein each vibratory source of the set n of vibratory sources is actuated based on the product S n .
20 . The system of claim 19 , wherein the processor is further configured to:
calculate a continuous signal C n for each set n of the plural vibratory sources.