Utilization of dynamic downhole surveying measurements

Patent metadata

Field	Value
Publication number	US-9982525-B2
Application number	US-201213429173-A
Country	US
Kind code	B2
Filing date	Mar 23, 2012
Priority date	Dec 12, 2011
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A method for making dynamic gravity toolface measurements while rotating a downhole measurement tool in a borehole is disclosed. The method includes processing magnetic field measurements and accelerometer measurements to compute a toolface offset and further processing the toolface offset in combination with a magnetic toolface to obtain the dynamic gravity toolface. Methods for correcting dynamic and static navigational sensor measurements to remove sensor biases, for example, are also disclosed.

First claim

What is claimed is:

1. A method of drilling in a borehole, comprising:
(a) deploying and rotating a bottom hole assembly (BHA) in the borehole, the bottom hole assembly comprising a downhole tool, a drill bit, and a steering tool, the downhole tool including first and second cross-axial magnetic field sensors and first and second cross-axial accelerometers;
(b) causing the downhole tool to make first and second cross-axial magnetic field measurements and first and second cross-axial accelerometer measurements while the downhole tool is rotating in (a), wherein the first and the second cross-axial magnetic field measurements do not include a z-axis magnetic field measurement;
(c) processing the cross-axial magnetic field measurements obtained in (b) to compute a magnetic toolface;
(d) processing the cross-axial magnetic field measurements and the cross-axial accelerometer measurements obtained in (b) to compute a dynamic toolface offset, wherein the dynamic toolface offset is computed over a plurality of measurements according to the following equation:

T
-
M

=

arc
⁢

⁢

tan
[

∑

⁢

(

B
x

⁢

A
y

-

B
y

⁢

A
x

)

-

∑

⁢

(

B
x

⁢

A
x

+

B
y

⁢

A
y

)

]

wherein T−M represents the dynamic toolface offset with T representing a gravity toolface and M representing the magnetic toolface, B x and B y represent the first and second cross-axial magnetic field measurements, and A x and A y represent the first and second cross-axial accelerometer measurements;
(e) processing the magnetic toolface computed in (c) and the dynamic toolface offset computed in (d) to compute a dynamic gravity toolface;
(f) processing the gravity toolface computed in (e) in a rotary steerable tool deployed in the BHA to compute a direction of subsequent drilling of the wellbore; and
(g) adjusting the rotary steerable tool to change a direction of drilling along the direction of subsequent drilling computed in (f).

2. The method of claim 1 , wherein the magnetic toolface is computed in (c) according to a following mathematical equation of:

M
=

arc
⁢

⁢
tan
⁢

B
x

B
y

3. The method of claim 1 , wherein (d) further comprises:
(i) processing the cross-axial magnetic field measurements and the cross-axial accelerometer measurements obtained in (b) to compute a preliminary dynamic toolface offset;
(ii) processing the magnetic tool face obtained in (c) to compute a rotation rate of the downhole tool; and
(iii) processing the preliminary dynamic toolface offset and the rotation rate of the downhole tool to compute the dynamic toolface offset.

4. The method of claim 3 , wherein (iii) comprises correcting the preliminary dynamic toolface offset to a zero-rpm equivalent value.

5. The method of claim 1 , further comprising:
(h) processing the dynamic gravity toolface computed in (e) in combination with logging while drilling data to create a logging while drilling image.

6. The method of claim 1 , wherein the downhole tool is one of a logging while drilling tool and a rotary steerable tool.

7. The method of claim 1 , where (a) further comprises utilizing a downhole controller to control a rotation rate of the downhole tool with respect to the borehole.

8. The method of claim 1 , wherein the downhole tool and the steering tool are within the same housing.

9. The method of claim 1 , wherein (g) comprises extending one or more blades on the rotary steerable tool to change the direction of drilling along the direction of subsequent drilling computed in (f).

Assignees

• Brooks Andrew G
• Sugiura Junichi
• Schlumberger Technology Corp

Inventors

• Brooks Andrew G
• Sugiura Junichi

Classifications

• E21B47/022 Primary

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