[First Hit]

Datapages, Inc.Print this page

Wavelet-Consistent Reprocessing of Multi-Environment 3D Seismic from Abu Dhabi

By

 Michael P. West1, Erik Kleiss2, Abu Baker Al Jeelani2, Mohamad Samir Al Nahhas2, Constantine Tsingas1

(1) Petroleum Geosciences Services, Cairo, Egypt (2) Abu Dhabi Company for Onshore Oil Operations (ADCO), Abu Dhabi, United Arab Emirates

 A vibroseis survey was reprocessed jointly with an adjacent transition zone survey. Data of high temporal and lateral resolution, and of good structural and stratigraphic accuracy is required here for mapping of subtle faults and improved reservoir characterization. Accurate Previous HitstaticsNext Hit solutions and reliable wavelets are critical - here 6ms false structure can make the difference of an oil well or one in the water. The older data has laterally variable bandwidth, phase and structural errors, resulting from inadequate Previous HitstaticsNext Hit and from unsatisfactory matching of source- and receiver types.

Consistent data character requires good wavelet Previous HitcorrectionsNext Hit for the various source-receiver combinations. In our reprocessing, partly-deterministic and partly-statistical (PDPA) zero-phasing dealt with these issues. Well-proven deterministic phase Previous HitcorrectionsNext Hit were applied to the vibroseis data. A statistical deconvolution ("PSW designature") was used for zerophasing the impulsive-source data and removing the hydrophone ghosts. This route avoids ad-hoc phase matching of overlapping parts of the data. Our method was validated using numerous comparisons of pre-stack and stacked data.

All data were zero-phased before first-arrival picking and Previous HitrefractionNext Hit Previous HitstaticsNext Hit, ensuring consistency between Previous HitstaticsNext Hit-related and zerophasing-related time shifts. This avoids structural errors resulting from lateral phase variability. Phase-corrected impulsive-source first arrivals were found consistent with those for zero-phased vibroseis.

This approach for matching the various data types yields a consistent data character across the combined surveys. The easier correlation of first-arrival data and absence of any post-Previous HitstaticsNext Hit space-variant phase Previous HitcorrectionsTop is expected to improve the structural accuracy.