Nondestructive downhole seismic vibrator source and processes of utilizing the vibrator to obtain information about geologic formations

• US 4,805,725 A
• Filed: 09/10/1987
• Issued: 02/21/1989
• Est. Priority Date: 03/18/1986
• Status: Expired due to Term

• Current Assignee: Chevron Research Company (Chevron Corp.)
• Original Assignee: Chevron Research Company (Chevron Corp.)
• Inventors: Paulsson, Bjorn N. P.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Eldred, John W.
• Application Number:
  US07/095,291
• Time in Patent Office: 530 Days
• Field of Search: 367/25, 367/36, 367/37, 367/911, 367/912, 367/75, 367/89, 181/101, 181/102, 181/104, 181/105, 181/106, 181/108, 181/111, 181/113, 181/121, 73/152, 175/40, 166/66
• US Class Current: 181/106
• CPC Class Codes: G01V 1/145 by deforming or displacing surfaces , e.g. by mechanically driven vibroseis™
• CPC Class Codes: G01V 1/42 using generators in one well and receivers elsewhere or vice versa G01V1/52 takes precedence
• CPC Class Codes: G01V 11/005 Devices for positioning logging sondes with respect to the borehole wall centralising devices for drilling rods or pipes E21B17/10; setting or locking tools in boreholes E21B23/00; locating objects in boreholes E21B47/09
• CPC Class Codes: G01V 2210/161 Vertical seismic profiling [VSP]
• CPC Class Codes: Y10S 367/911 Particular well-logging apparatus
• CPC Class Codes: Y10S 367/912 Particular transducer

Abstract

The invention relates to a nondestructive downhole seismic source capable of generating S_V -waves, S_H -waves, and P-waves alone or in combination to determine information about a surrounding geologic formation. The invention also includes processes of performing crosswell tomography and reverse vertical seismic profiling. The invention also includes a means and process to carry out in hole seismic logging operations.

Claims

1. A downhole seismic source comprising:

a housing;

means for clamping the housing in a well bore;

a reaction mass in said housing, said reaction mass oriented to move generally perpendicular to the well bore axis;

means for hydraulically moving said reaction mass such that forces are transmitted through, through said clamp and into the well bore to generate at least one detectable seismic wave of predetermined frequencies to said housing; and

means for rotating said reaction mass around an axis generally parallel to the well bore axis so as to orientate said mass in a selected direction.

2. The source as recited in claim 1 further comprising a means for determining an orientation of said source.

3. The source as recited in claim 2 wherein said means for determining an orientation is a downhole gyro.