Method of imaging overturned waves

A method for imaging an underground interface in a zone within a variable seismic velocity media where a natural resource may be located, wherein said interface is oriented such that an overturned wave is generated by an impressed seismic motion, said method comprising:

• impressing one or more seismic motions from a seismic source into said media beginning at time t.sub.0 ;
• detecting a set of reflected seismic motions from said interface at a plurality of detector locations, at least one of said detectors located at an offset distance from said source, wherein said detectors and seismic source form a seismic system producing seismic data;
• imaging said underground interface using said seismic data and a linearly transformed wave equation without a data stacking step;
• identifying overturned waves reflected from said underground interface in said seismic data prior to said imaging step;
• recovering said natural resource based at least in part upon said imaging, wherein at least a portion of said detecting is accomplished over a period of time which begins after t.sub.0 plus 2 seconds;
• and
• after the identifying step and before the imaging step, also comprises the steps of:
• calculating receiver and source locations, a second offset distance, and a second period of time based at least in part on said seismic data;
• relocating said seismic system to the calculated locations;
• second impressing one or more seismic motions from a seismic source;
• and
• detecting a second set of reflected wave data at one or more relocated detectors over a second period of time.

A method for imaging an underground interface in a zone where a natural resource may be located, wherein a tangent to said interface is oriented such that an overturned wave is generated when a seismic motion is impressed into said zone, said method comprising:

• impressing one or more seismic motions from a seismic source into said zone beginning at t.sub.0 ;
• detecting a first set of reflected seismic motions from said interface at a plurality of detector locations, one of said detectors located at an offset distance from said source, wherein said detectors and seismic source form a seismic system producing seismic data and detecting is accomplished over a time section;
• identifying overturned waves reflected from said underground interface in said seismic data;
• calculating a second offset distance and second locations for the elements of said seismic system, and a second time section based at least in part on said seismic data;
• relocating said seismic system to the calculated second locations;
• impressing one or more seismic motions from a seismic source;
• detecting a second set of reflected seismic data at one or more relocated detectors over a second time section;
• imaging said underground interface based at least in part on said second set of reflected data;
• and
• recovering said natural resource based at least in part upon said imaging.

A method for imaging an underground interface in a zone where a natural resource may be located, wherein said interface is oriented such that an overturned wave is generated when a seismic motion is impressed into said zone, said method comprising:

• impressing one or more seismic motions from a seismic source into said zone beginning at t.sub.0 ;
• detecting a set of reflected seismic motions from said interface at a plurality of detector locations, one of said detectors located at an offset distance from said source, wherein said detectors and seismic source form a seismic system producing seismic data and detecting is accomplished over a time section;
• identifying overturned waves reflected from said underground interface in said seismic data;
• calculating overturned wave raypath and travel times using an interactive modeling program;
• relocating at least a portion of said seismic system such that said detector is offset a second offset distance from said seismic source;
• impressing a second seismic motion at a second t.sub.0 and detecting a second set of reflected seismic motions forming a second data set, wherein said detecting is accomplished over a second time section extending 6 seconds or more after t.sub.0 ;
• imaging said underground interface using a linearly transformed wave equation based method in the absence of a data stacking step;
• and
• recovering said natural resource based at least in part upon said imaging.

A seismic source and receiver apparatus for imaging an overturned interface within an underground formation having a variable seismic velocity, said apparatus comprising:

• a source of impressing a seismic wave into said media capable of reaching said overturned interface;
• at least one receiver of reflected wave data from said overturned interface, wherein said receiver is offset 239 meters or more from said source;
• and
• means for imaging said interface from said wave data without a stacking step.

An seismic source and receiver apparatus for imaging an interface capable of generating overturned waves within an underground formation having a variable seismic velocity, said apparatus comprising:

• a source of a seismic wave capable of reaching said interface;
• at least one detector located at an offset distance from said source forming a seismic system, said detector capable of detecting reflected seismic waves from said overturned interface after said source impresses said seismic wave;
• means for interactively calculating a raypath and a travel time of seismic waves from various locations of said source and to various locations of said detector;
• means for relocating said seismic system based at least in part on said raypath and travel time calculations;
• and
• means for imaging said interface based upon at least in part on seismic data from said relocated seismic system.