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Real Time Automated Slide-Rotate Decision for Drilling With Bent Motors

IP.com Disclosure Number: IPCOM000248940D
Publication Date: 2017-Jan-23

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 13% of the total text.

REAL TIME AUTOMATED SLIDE-ROTATE DECISIONS FOR DRILLING WITH BENT MOTORS

BACKGROUND

[0001] Boreholes are drilled into earth formations for various purposes such as

hydrocarbon production, geothermal production, and carbon dioxide sequestration. A

borehole may be drilled using a drill string and a bent motor to rotate a drill bit in order to

follow a planned trajectory. Typically, the drill string is rotated at the surface of the earth

using a topdrive in order to rotate the drill bit, which cuts or disintegrates formation rock

to form the borehole in a straight trajectory. This process is referred to as “rotating”

mode. When the borehole direction needs to change, the rotation of the drill string is

stopped and the bent motor drills the borehole in the changed direction. This process is

referred to as “sliding” mode. In general, drilling in the rotating mode is more efficient

and has a higher rate-of-penetration (ROP) than in the sliding mode. Unfortunately, use

of the rotating mode more frequently than the sliding mode while drilling the borehole to

maintain a high ROP may lead to a tortuous path that may negatively affect equipment

disposed in the borehole. For example, the drill string may undergo severe bending loads

and wireline logging tools may get stuck in the borehole. Hence, it would be appreciated

in the drilling industry if methods and apparatuses were developed that could balance the

use of the rotating mode and the sliding mode while boreholes are being drilled in order

to form a borehole geometry that meets other criteria.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The following descriptions should not be considered limiting in any way. With

reference to the accompanying drawings, like elements are numbered alike:

[0003] FIG. 1 is a cross-sectional view of an embodiment of a drill string having a bent

motor disposed in a borehole penetrating the earth;

[0004] FIG. 2 is a flow chart for a method for drilling a borehole penetrating an earth

formation;

[0005] FIG. 3 depicts aspects of a borehole trajectory by simulating a rotating mode and

a sliding mode; and

[0006] FIG. 4 depicts aspects of using the rotating modes and the sliding modes for

drilling in simulation the borehole trajectory.

DETAILED DESCRIPTION

[0007] A detailed description of one or more embodiments of the disclosed apparatus and

method presented herein by way of exemplification and not limitation with reference to

the figures.

[0008] Disclosed are embodiments of methods and apparatuses for drilling a borehole in

an earth formation using a drill bit powered by a drill string in a “rotating” mode or a bent

motor in a “sliding” mode. The methods and apparatuses involve building a

mathematical model of the drill string, bent motor, and drill bit in the borehole and using

the model to estimate a time interval for using the rotating mode and a time interval for

using the sliding mode in order to efficiently drill the borehole in a desired trajectory and

still meet other c...