System and method for performing seismic surveys with a controlled source using maximum-power sweeps

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons, the method comprising:

• (a) selecting a seismic source, said seismic source comprising a piston for generating a controllable swept frequency signal;
• (b) determining at least a maximum piston displacement, a maximum piston velocity, and a maximum piston acceleration;
• (c) using said maximum piston displacement to calculate a displacement limit curve;
• (d) using said maximum piston velocity to calculate a velocity limit curve;
• (e) using said maximum piston acceleration to calculate an acceleration limit curve;
• (f) using said displacement limit curve, said velocity limit curve, and said acceleration limit curve to determine a constrained limit curve;
• (g) using said constrained limit curve to design a sweep schedule for said seismic source whereby the seismic source operates at or near its maximum acoustic power output across the sweep schedule;
• and,
• (h) using said sweep schedule to collect seismic data proximate to said region of the subsurface of the earth, thereby exploring within said region of the subsurface of the earth.

A controllable swept frequency seismic source, comprising:

• (a) a housing;
• (b) a piston within said housing, said piston at least for generating a swept frequency seismic signal;
• and,
• (c) a controller in electronic communication with said piston, said controller containing a sweep schedule for moving said piston within said housing to generate said swept frequency seismic signal, wherein said sweep schedule is determined by a method comprising:
• (c1) determining for said piston at least a maximum piston displacement value, a maximum piston velocity value, and a maximum piston acceleration value;
• (c2) using said maximum piston displacement value to calculate a displacement limit curve;
• (c3) using said maximum piston velocity value to calculate a velocity limit curve;
• (c4) using said maximum piston acceleration value to calculate an acceleration limit curve;
• (c5) using said displacement limit curve, said velocity limit curve, and said acceleration limit curve to determine a constrained limit curve, wherein each of said displacement limit curve, said velocity limit curve, and said acceleration limit curve is a function of frequency, and wherein each of said limiting curves is based on a volume acceleration constraint;
• and,
• (c6) using said constrained limit curve to design said sweep schedule for said seismic source.

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons, the method comprising:

• (a) selecting a seismic source, said seismic source comprising a piston for generating a controllable swept frequency signal;
• (b) determining a maximum piston displacement, a maximum piston velocity, a maximum piston acceleration, and a maximum piston jerk;
• (c) for each of said determined maximum piston displacement, maximum piston velocity, maximum piston acceleration, and maximum piston jerk, calculating a corresponding limit curve;
• (d) using said corresponding limit curves to determine a constrained limit curve;
• (e) using said constrained limit curve to design a sweep schedule for said seismic source;
• and,
• (f) using said sweep schedule to collect seismic data proximate to said region of the subsurface of the earth, thereby exploring within said region of the subsurface of the earth.

A method of seismic exploration of a subsurface target, the method comprising:

• (a) accessing a plurality of seismic traces collected proximate to said subsurface target, wherein said plurality of seismic traces are acquired by a collection method comprising:
• (a1) selecting a seismic source, said seismic source comprising a piston for generating a controllable swept frequency signal;
• (a2) determining a maximum piston displacement, a maximum piston velocity, a maximum piston acceleration, and a maximum piston jerk;
• (a3) for each of said determined maximum piston displacement, maximum piston velocity, maximum piston acceleration, and maximum piston jerk, calculating a corresponding limit curve;
• (a4) using said corresponding limit curves to determine a constrained limit curve;
• (a5) using said constrained limit curve to design a sweep schedule for said seismic source;
• (a6) using said sweep schedule to collect said plurality of seismic traces proximate to said subsurface target;
• and,
• (b) using at least a portion of said accessed plurality of processed seismic traces to explore for hydrocarbons proximate to said subsurface target.