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dc.contributor.authorRector, James  Concept link
dc.contributor.authorLiu, Zhuping  Concept link
dc.date.accessioned2016-07-06T18:38:52Z
dc.date.available2016-07-06T18:38:52Z
dc.date.issued2001
dc.identifier.urihttps://hdl.handle.net/1912/8088
dc.description.abstractSeismic-While-Drilling (SWD), also termed TomexR is a technique that monitors the seismic signals created during rotary drilling using a pilot sensor located near the top of the drillstring along with 'earth' sensors deployed near the surface of the earth. Cross-correlations between the pilot sensor signal and each of the earth sensors are used to attenuate incoherent noise and to compute traveltime differences between signals received at the earth sensors and signals received at the pilot sensor. By compensating for the delay and multipath filtering created by propagation in the drillstring, the correlated signals can be processed to create a data set equivalent to an inverse VSP, with a point source at the drill bit and a receivers near the earth's surface. Real-time information from the SWD data such as interval and average velocities and reflectivity ahead of the bit are used commonly by the oil industry to position the drill bit on the (time) seismic section, predict overpressure, and steer the bit in the case of deviated wells. In some cases, logging runs cannot be made after the hole is drilled (due to stability problems), and SWD data may be the only borehole geophysical data recorded. The attractive characteristics of SWD make it a natural for ODP cruises, where hole conditions sometimes make it impossible to perform wireline logging.en_US
dc.description.sponsorshipThis work was supported by the National Science Foundation (NSF Grant Number OCE - 9730588).en_US
dc.language.isoen_USen_US
dc.publisherWoods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Technical Memorandaen_US
dc.relation.ispartofseriesWHOI-02-2001en_US
dc.subjectBoringen_US
dc.subjectData processingen_US
dc.titleSeismic-while-drilling on ODP holes 1107 and 1105A : a preliminary report on correlation processingen_US
dc.typeWorking Paperen_US
dc.identifier.doi10.1575/1912/8088


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