| US 7,558,153 B2 | ||
| Radial profiling of slowness: methods and apparatus for near-wellbore alteration estimation | ||
| Smaine Zeroug, Paris (France); Henri-Pierre Valero, Danbury, Conn. (US); and Sandip Bose, Chestnut Hill, Mass. (US) | ||
| Assigned to Schlumberger Technology Corporation, Ridgefield, Conn. (US) | ||
| Filed on Nov. 23, 2005, as Appl. No. 11/286,790. | ||
| Claims priority of provisional application 60/672565, filed on Apr. 19, 2005. | ||
| Prior Publication US 2006/0233047 A1, Oct. 19, 2006 | ||
| Int. Cl. G01V 1/40 (2006.01) | ||
| U.S. Cl. 367—27 [367/31] | 29 Claims |
| 1. A method of logging an earth formation surrounding a borehole, comprising:
providing a logging device that is moveable through the borehole;
transmitting sonic energy into the formation and receiving, at a plurality of transmitter-to-receiver spacings on the logging
device, sonic energy that has traveled through the formation, and producing signals representative of the received sonic energy
for the plurality of transmitter-to-receiver spacings;
determining, from the signals, differential transit time data for selected receiver pairs at respective transmitter-to-receiver
pair spacings;
fitting the differential transit times data to a basis set of spline functions; and
providing, from the spline fitted differential transit time, a continuous and quantitative radial profile image of formation
slowness as a function of the radius of the borehole.
|