Subsurface imaging with reverse vertical seismic profiles

This thesis presents imaging results from a 3D reverse vertical seismic profile (RVSP) dataset measured at a hydrocarbon bearing pinnacle reef in northern Michigan. The study presented many challenges in seismic data processing and imaging, as the survey geometry was unique in several ways. Reverse VSP, which uses seismic sources in a borehole and receivers on the earth's surface, is fairly rare. RVSP in 3D with a random distribution of surface geophones is unprecedented. At the time this data was collected, no commercially available processing tools existed to address this geometry, so a processing scheme had to be developed. The data processing sequence presented in this thesis, which includes amplitude corrections, first break picking, deconvolution, wavefield separation, and application of statics, takes advantage of the repeatible signature of the new downhole source (Paulsson et al., 1998). Since the data can be handled in common-receiver gathers instead of the usual common-source gathers, it can be treated like several single offset VSPs during the processing sequence. Issues related to the 3D geometry and the random distribution of the receiver array need not be addressed until the imaging step. The generalized Radon transform (GRT) migration method of Miller et al. (1987) provides a high resolution image of a portion of the target reef at 4600 feet (1400 meters) depth. The high resolution of the image is largely due to the downhole source, which generated a high powered signal at frequencies up to several hundred Hertz. Another factor in the high resolution of the image is the success of receiver consistent model-based Wiener deconvolution (Haldorsen et al., 1994), possible because the source signature was repeatable. Due to adverse conditions and power system failure, a large portion of the surface array did not record data.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Krasovec, Mary L. (Mary Lee), 1972-

Advisor dc:contributor.advisor

• M. Nafi Toksöz.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/59648

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/59648