3-D PRESTACK KIRCHHOFF DEPTH MIGRATION - FROM PROTOTYPE TO PRODUCTIONIN A MASSIVELY-PARALLEL PROCESSOR ENVIRONMENT

Portable, production-scale 3-D prestack Kirchhoff depth migration soft ware capable of full-volume imaging has been successfully implemented and applied to a six-million trace (46.9 Gbyte) marine data set from a salt/subsalt play in the Gulf of Mexico. Velocity model building and updates use an image-driven strategy and were performed in a Sun Spare environment. Images obtained by 3-D prestack migration after three ve locity iterations are substantially better focused and reveal drilling targets that were not visible in images obtained from conventional 3- D poststack time migration. Amplitudes are well preserved, so anomalie s associated with known reservoirs conform to the petrophysical predic tions. Prototype development was on an 8-node Intel iPSC860 computer; the production version was run on an 1824-node Intel Paragon computer. The code has been successfully ported to GRAY (T3D) and Unix workstat ion (PVM) environments.