The Virtual Source Method

The virtual source method is an geophysical techniqueto image and monitor the Earth's subsurface below acomplicated and time-varying overburden without theknowledge of overburden velocities and near-surfacechanges. It is based on extracting the responsebetween a given pair of receivers by correlating thewavefields recorded by them and stacking over thephysical sources. The virtual source method requiressurface shooting recorded by subsurface receiversplaced below the distorting or changing part of theoverburden. Redatuming the recorded response to thereceiver locations allows the reconstruction of acomplete downhole survey as if the sources were alsoburied at the receiver locations. The ability toredatum the data independent of the knowledge ofcomplicated and time-varying overburden velocitiesmakes the virtual source method a valuable tool forimaging and time-lapse monitoring.

Autorentext

Kurang Mehta is a Research Geophysicist at Shell International E & P, Inc., Houston, TX, USA. He completed his B.E in Electronics Engineering from M S University of Baroda, India in 2001, M.S in Electrical Engineering from N C State University, Raleigh, NC, USA in 2003 and Ph.D in Geophysics from Colorado School of Mines, Golden, CO, USA in 2007.

Klappentext
The virtual source method is an geophysical technique to image and monitor the Earth's subsurface below a complicated and time-varying overburden without the knowledge of overburden velocities and near-surface changes. It is based on extracting the response between a given pair of receivers by correlating the wavefields recorded by them and stacking over the physical sources. The virtual source method requires surface shooting recorded by subsurface receivers placed below the distorting or changing part of the overburden. Redatuming the recorded response to the receiver locations allows the reconstruction of a complete downhole survey as if the sources were also buried at the receiver locations. The ability to redatum the data independent of the knowledge of complicated and time-varying overburden velocities makes the virtual source method a valuable tool for imaging and time-lapse monitoring.