SYSTEMS, DEVICES AND METHODS FOR BOREHOLE GRAVIMETRY
First Claim
1. A method for measuring gravitational acceleration, the method comprising:
- locating a gravimeter within a borehole, wherein the gravimeter includes a proof mass that is constrained by at least one spring;
generating a light path from a light source to a reflective surface on the proof mass; and
determining spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium by measuring a change in length of the light path.
1 Assignment
0 Petitions
Accused Products
Abstract
A gravimeter, a gravimeter system, and a method for measuring gravitational acceleration within a borehole are described herein. The gravimeter includes a proof mass that is constrained by springs and an optical interferometer for measuring displacement of the proof mass. The optical interferometer generates a light path from a light source to a reflective surface on the proof mass. Spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium is determined by measuring a change in length of the light path. In turn, gravitational acceleration can be determined from the spatial displacement of the proof mass. A number of such gravimeters can be used in a gravimeter system to make measurements of gravitational acceleration in variety of different directions.
-
Citations
29 Claims
-
1. A method for measuring gravitational acceleration, the method comprising:
-
locating a gravimeter within a borehole, wherein the gravimeter includes a proof mass that is constrained by at least one spring; generating a light path from a light source to a reflective surface on the proof mass; and determining spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium by measuring a change in length of the light path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A gravimeter comprising:
-
a proof mass that is constrained by at least one spring and that is displaceable in response to gravitational acceleration; an optical interferometer for measuring displacement of the proof mass, wherein the optical interferometer comprises a light source and is configured to generate a light path from the light source to a reflective surface on the proof mass; and a processor in electronic communication with the optical interferometer, wherein the processor is configured to determine spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium by measuring a change in length of the light path. - View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. A borehole tool comprising:
-
a first set of gravimeters, wherein the first set includes a plurality of gravimeters oriented to detect gravitational acceleration in at least two different directions; a second set of gravimeters, wherein the second set includes a plurality of gravimeters oriented to detect gravitational acceleration in at least two different directions; and wherein the first set of gravimeters and the second set of gravimeters are spaced apart from each other by a known distance. - View Dependent Claims (17, 18, 19, 20, 21, 22)
-
-
23. A method for determining a characteristic of a formation, the method comprising:
-
using a first set of gravimeters to perform a first set of measurements that includes gravitational acceleration in at least two different directions at a first position within a borehole; using a second set of gravimeters to perform a second set of measurements that includes gravitational acceleration in at least two different directions at a second position within the borehole, wherein the first position and second position are spaced apart from each other by a known distance; and determining a first density at a location within the formation using the first set of measurements and the second set of measurements. - View Dependent Claims (24, 25, 26, 27, 28, 29)
-
Specification