Gravity techniques for drilling and logging

• US 7,069,780 B2
• Filed: 03/22/2004
• Issued: 07/04/2006
• Est. Priority Date: 03/21/2003
• Status: Expired due to Fees

• Current Assignee: Ander Laboratory, Inc.
• Original Assignee: Ander Laboratory, Inc.
• Inventors: Ander, Mark E.
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US10/806,049
• Publication Number:
  US 20040250614A1
• Time in Patent Office: 834 Days
• Field of Search: 733/82.R, 733/82.G, 731/520.2, 731/520.3, 731/520.5, 175/40, 175/45, 175/50, 175/73, 175/61, 166/252.2
• US Class Current: 73/382.00R
• CPC Class Codes: G01V 7/00 Measuring gravitational fields or waves; Gravimetric prospecting or detecting

Abstract

Techniques for using gravity in applications such as drilling and logging. Techniques are present for (1) gravity well logging using gravity sensors arrays; (2) creating density pseudosections using gravity measurements; (3) performing Gravity Measurement While Drilling (GMWD) using single or multiple gravity sensors; and (4) geosteering using GMWD.

Claims

1. An apparatus comprising:

a subsurface logging apparatus; and

a plurality of gravity sensors coupled to the subsurface logging apparatus, the sensors being spaced a known, distance apart to form a gravity sensor array, where different gravity sensors are spaced at different distances from one another.

2. The apparatus of claim 1, the logging apparatus comprising a logging sonde, coil tubing, or wireline.

3. The apparatus of claim 1, where a sensor drift associated with one gravity sensor is time-correlated with a sensor drift of another gravity sensor.

4. The apparatus of claim 3, where sensor drifts of all the gravity sensors are time-correlated with one another.

5. The apparatus of claim 1, further comprising sensor hardware or software configured to correct sensor drift of one or more of the gravity sensors.

6. The apparatus of claim 1, where the array is a linear, vertical array.