Downhole closed-loop geosteering methodology

Patent metadata

Field	Value
Publication number	US-9273517-B2
Application number	US-85941610-A
Country	US
Kind code	B2
Filing date	Aug 19, 2010
Priority date	Aug 19, 2010
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A closed-loop method for geosteering includes acquiring logging while drilling data and processing the logging while drilling data downhole while drilling to obtain a geosteering correction (a correction to the drilling direction based upon the LWD measurements). The geosteering correction is further processed downhole to obtain new steering tool settings which are then applied to the steering tool to change the direction of drilling. These steps are typically repeated numerous times without the need for uphole processing or surface intervention.

First claim

We claim:

1. A closed-loop method for geosteering a subterranean borehole, the method comprising:
(a) rotating a bottom hole assembly in a subterranean borehole, the bottom hole assembly including a drill bit, a steering tool, a directional resistivity logging while drilling tool, a downhole processor, and signal processing front-end circuitry in electronic communication with the downhole processor, wherein the signal processing front-end circuitry includes at least one transmitter circuit, at least one receiver circuit, and at least one additional processing circuit in communication with the at least one receiver circuit;
(b) causing the directional resistivity logging while drilling tool to acquire directional resistivity measurements while rotating in (a), wherein the directional resistivity measurements are acquired as a result of a signal being transmitted using the at least one transmitter circuit and the transmitted signal being received by the at least one receiver circuit, and wherein (b) further comprises providing synchronized azimuth measurements to at least one of the at least one receiver circuit or the at least one additional processing circuit to provide directional resistivity image formation;
(c) causing the downhole processor to compute a geosteering correction using the directional resistivity measurements acquired in (b);
(d) causing the downhole processor to compute new steering tool settings using the geosteering correction computed in (c); and
(e) applying the new steering tool settings computed in (d) to the steering tool while rotating the bottom hole assembly in (a).

2. The method of claim 1 , further comprising:
(f) repeating (b), (c), (d), and (e) a plurality of times while rotating the bottom hole assembly in (a).

3. The method of claim 1 , wherein (c) further comprises:
(i) causing the downhole processor to compute a geosteering well position using the directional resistivity measurements acquired in (b);
(ii) causing the downhole processor to compute the geosteering correction using the geosteering well position computed in (i).

4. The method of claim 3 , wherein the geosteering well position comprises at least a distance between the directional resistivity tool and a predetermined formation boundary layer.

5. The method of claim 1 , wherein (c) further comprises:
(i) causing the downhole processor to select directional resistivity values from a downhole lookup table that most closely match the directional resistivity measurements acquired in (b);
(ii) causing the downhole processor to select a geosteering well position from the downhole lookup table that corresponds with the directional resistivity logging while drilling values selected in (i);
(iii) causing the downhole processor to compute the geosteering correction using the geosteering well position selected in (ii).

6. The method of claim 5 , wherein the geosteering well position comprises a distance between the directional resistivity tool and a predetermined formation boundary layer.

7. The method of claim 1 , wherein the additional processing circuit provides a start beacon signal to a signaling board in communication with the transmitter circuit.

8. A closed-loop method for geosteering a subterranean borehole, the method comprising:
(a) rotating a bottom hole assembly in a subterranean borehole, the bottom hole assembly including a drill bit, a steering tool, a directional resistivity logging while drilling tool, and a downhole processor;
(b) causing the directional resistivity logging while drilling tool to acquire directional resistivity measurements while rotating in (a);
(c) causing the downhole processor to select directional resistivity values from a downhole lookup table, the directional resistivity values selected so that they most closely match the directional resistivity measurements acquired in (b);
(d) causing the downhole processor to select a geosteering well position from the downhole lookup table that corresponds with the directional resistivity logging while drilling values selected in (c);
(e) causing the downhole processor to compute a geosteering correction using the geosteering well position selected in (d);
(f) causing the downhole processor to compute new steering tool settings using the geosteering correction computed in (e); and
(g) applying the new steering tool settings computed in (f) to the steering tool while rotating the bottom hole assembly in (a).

9. The method of claim 8 , further comprising:
(f) repeating (b), (c), (d), and (e) a plurality of times while rotating the bottom hole assembly in (a).

10. The method of claim 8 , wherein the geosteering well position comprises at least a distance between the directional resistivity tool and a predetermined formation boundary layer.

11. The method of claim 8 , wherein the geosteering well position comprises a first distance between the directional resistivity tool and a first predetermined formation boundary layer and a second distance between the directional resistivity tool and a second predetermined formation boundary layer.

12. The method of claim 11 , wherein the geosteering well position further comprises a resistivity of a near bed, a resistivity of an upper bed, and a resistivity of a lower bed.

13. The method of claim 8 , wherein the bottom hole assembly of (a) further includes signal processing front-end circuitry in electronic communication with the downhole processor, wherein the signal processing front-end circuitry includes at least one transmitter circuit, at least one receiver circuit, and at least one additional processing circuit in communication with the at least one receiver circuit, and wherein the directional resistivity measurements in (b) are acquired as a result of a signal being transmitted using the at least one transmitter circuit and the transmitted signal being received by the at least one receiver circuit, and wherein (b) further comprises providing synchronized azimuth measurements to at least one of the at least one receiver circuit or the at least one additional processing circuit to provide directional resistivity image formation.

14. The method of claim 13 , wherein the additional processing circuit provides a start beacon signal to a signaling board in communication with the transmitter circuit.

15. A closed-loop method for geosteering a subterranean borehole, the method comprising:
(a) rotating a bottom hole assembly in a subterranean borehole, the bottom hole assembly including a drill bit, a steering tool, a directional resistivity logging while drilling tool, and a downhole processor;
(b) causing the downhole processor to compute a geometric well position from a borehole survey;
(c) causing the downhole processor to compute a geometric correction from the geometric well position computed in (b);
(d) causing the directional resistivity logging while drilling tool to acquire directional resistivity measurements while rotating in (a);
(e) causing the downhole processor to compute a geosteering correction using the directional resistivity measurements acquired in (d) by causing the downhole processor to select directional resistivity values from a downhole lookup table that most closely match the directional resistivity measurements acquired in (d), causing the downhole processor to select a geosteering well position from the downhole lookup table that corresponds with the selected directional resistivity values, and causing the downhole processor to compute the geosteering correction using the selected geosteering well position;
(f) causing the downhole processor to compute a combined corr

Assignees

• Tchakarov Borislav J
• Wang Tsili
• Guenther Rodney S
• Cao Thanh H
• Tang Caimu
• Schlumberger Technology Corp

Inventors

• Tchakarov Borislav J
• Wang Tsili
• Guenther Rodney S
• Cao Thanh H
• Tang Caimu

Classifications

• E21B47/26

  Storing data down-hole, e.g. in a memory or on a record carrier · CPC title

• E21B7/04 Primary

  Directional drilling · CPC title

• E21B47/022

  of the borehole, e.g. using geomagnetism · CPC title

• E21B7/10

  Correction of deflected boreholes · CPC title

• E21B47/124

  Fixed Constructions · mapped topic