US20130277114A1

US20130277114A1 - Sleeve for logging while drilling electromagnetic sensor

Info

Publication number: US20130277114A1
Application number: US13/449,940
Authority: US
Inventors: Jonathan F. Hook; John F. Groweg
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 2012-04-18
Filing date: 2012-04-18
Publication date: 2013-10-24

Abstract

An apparatus for measuring a characteristic of an earth formation includes a drill collar configured to be inserted into a borehole of the earth formation, an electromagnetic sensor on the drill collar, and a non-conductive sleeve surrounding a circumference of the drill collar including the electromagnetic sensor and configured to press directly against the electromagnetic sensor.

Description

BACKGROUND

Boreholes are drilled deep into the earth for many applications such as carbon sequestration, geothermal production, and hydrocarbon exploration and production. Electromagnetic sensors may be used to collect information about the earth around the borehole during a drilling operation. However, metal shields positioned around the electromagnetic sensors to prevent damage to the sensors may interfere with electromagnetic signals transmitted by the sensor and received by the sensor.

BRIEF SUMMARY

Disclosed is an apparatus for measuring a characteristic of an earth formation. The apparatus includes a drill collar configured to be inserted into a borehole of the earth formation, an electromagnetic sensor on the drill collar, and a non-conductive sleeve surrounding a circumference of the drill collar including the electromagnetic sensor and configured to press directly against the electromagnetic sensor.
Also disclosed is a system for an apparatus including a drill collar, a sensor located around the drill collar, and a non-conductive sleeve covering an entire outer surface of the sensor and configured to contact the outer surface of the sensor.
Further disclosed is a method including providing a drill collar in a wellbore, the drill collar including a sensor located on the drill collar and a non-conductive sleeve entirely covering the sensor and subjecting the non-conductive sleeve to a pressure to press the non-conductive sleeve against the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 illustrates a drill pipe segment according to an embodiment of the present disclosure;

FIGS. 2A and 2B illustrate a portion of the drill pipe segment according to an embodiment of the present disclosure;

FIG. 3 illustrates a portion of a drill pipe according to another embodiment of the present disclosure; and

FIG. 4 illustrates a method according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

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.
FIG. 1 illustrates a portion of a drill pipe 100 according to one embodiment of the present disclosure. The portion of the drill pipe 100 includes a drill collar 110, a sensor 120, and a sleeve 130 covering the sensor 120 in a radial direction.
The drill collar 110 may be made of a metal material such as steel and in one embodiment, the drill collar 110 includes a conduit 111 to transmit wires, cables, fluids, or any other materials. For example, wires or cables may extend through the conduits 111 of multiple drill collars 110 connected end-to-end. Likewise, fluids maybe transmitted through the conduits 111 of multiple drill collars 110 connected end-to-end. In one embodiment, the drill collar 110 includes multiple conduits 111.
The sensor 120 is located on the drill collar 110 radially outward from a center axis of the drill collar. In one embodiment, the sensor surrounds the drill collar 110. For example, the sensor may be an electromagnetic sensor and may include one or more coils wound around an outside surface of a sensor and recessed in the drill collar 110. In one embodiment, the sensor 120 includes a coil portion 121 and a base portion 122. The base portion 122 may include one or more materials, such as magnetic materials, non-magnetic materials, ferromagnetic materials, insulating materials, conductive materials, non-conductive materials, or other materials according to design considerations of the sensor 120. For example, in one embodiment the base portion 122 is a shielding chassis that isolates the coil portion 121 from the drill collar 110, which may be made of metal. In one embodiment, the sensor 120 is recessed in the drill collar 110, such that an outer surface of the drill collar 110 has a diameter greater than an outer diameter of the sensor 120.
The sleeve 130 extends over an entire outer surface of the sensor 120. In one embodiment, the sleeve 130 has a cylindrical shape. In one embodiment, the sleeve 130 is formed to have no holes or stress risers, such as welds, ridges, or other protrusions. For example, the sleeve 130 may be formed in an extrusion process to maintain uniform material properties and smooth surface.
In one embodiment, the sleeve 130 is non-conductive, and in one embodiment the sleeve 130 is a non-metal material. For example, in one embodiment, the sleeve 130 is made of a high-temperature rated plastic or polymer, such as polyether ether ketone (PEEK).
The sleeve 130 is located over the sensor 120 to have either a small space or no space 132 between the sleeve 130 and the sensor 120 when no inward pressure is applied to the sleeve 130, or when a sea-level or above-ground-level pressure is applied to the sleeve 130. However, the sleeve 130 may be configured to press against the sensor 120 when pressure is applied to the sleeve 130. In embodiments of the present disclosure, the pressure is a pressure within a well bore of an earth formation. For example, in one embodiment a predetermined pressure level is determined at which a drill collar 110 will operate in a well bore, and the sleeve 130 is configured of such a thickness and material to press against the sensor 120 at the predetermined pressure.
When the drill pipe 100 is inserted into a well-bore, pressures in the well-bore may press against the sleeve 130, which then may press against the sensor 120. The pressures in the well bore may be generated due to hydrostatic pressures within the well bore including pressures resulting from a depth of the well bore, fluid in the well bore, and pressures generated due to a drilling operation performed by a drill connected to the drill pipe 100.
In embodiments of the present disclosure, the sleeve 130 is configured to press against substantially an entire outer radial surface of the sensor 120. In the present specification and claims, the term “substantially the entire surface” refers to at least 80% of the outer radial surface of the sensor 120, such as 90% or 95% of the outer radial surface of the sensor. In embodiments of the present disclosure, the gap 132 between the sleeve 130 and the sensor 120 is very small, such as between 1/1000 inch and 1/10,000 inch, such that the sleeve 130 deforms only a very small amount when pressure is applied to the sleeve 130. In other words, the gap 132 may be sufficient only to allow for statistical variations in parts dimensions, such as sensor 120 dimensions or drill collar 110 dimensions.
In embodiments of the present disclosure, the drill collar 110 includes a slot or groove 112 located at axial ends of the sleeve 130 to receive a sealing member, such as an O-ring, to form a hermetic seal between the sleeve 130 and the drill collar 110 to prevent fluids from contacting the sensor 120. When a pressure is applied to the sleeve 130, the sleeve 130 applies pressure to the sealing members, strengthening the hermetic seal.
FIGS. 2A and 2B further illustrate a portion of the drill pipe 100 according to embodiments of the present disclosure. For purposes of description, FIGS. 2A and 2B illustrate only sections of the drill pipe 100 corresponding to the portion A indicated in FIG. 1.
The drill pipe 100 includes the drill collar 110 having a recess formed therein to receive the sensor 120, the seal members 140, and the sleeve 130. The sensor 120 includes the base portion 122 and the coil portion 121, and an inner radial surface 121 b of the coil portion 121 contacts an outer radial surface 122 a of the base portion 122. The drill collar 110 includes the grooves 112 to receive therein the seal members 140. In one embodiment, the seal members 140 are O-rings that encircle the drill collar 110.
The sleeve 130 may be located on the seal members 140, and the sleeve 130, seal members 140, and drill collar 110 may together form the hermetic seal to prevent air and fluid from contacting the sensor 120. When no pressure is applied to the non-conductive sleeve 130, as illustrated in FIG. 2A, a gap 132 may be present between an inner radial surface 130 b of the sleeve 130 and an outer radial surface 121 a of the coil portion 121 of the sensor 120. In one embodiment, the gap 132 corresponds to an extent that the seal members 140 extend radially outward form the sensor 120 and the recessed portion of the drill collar 110.
In one embodiment, the gap 132 is of a sufficient size only to allow for statistical variations in parts dimensions, such as sensor 120 dimensions or drill collar 110 dimensions. In other words, the gap 132 may be designed to be as close to zero as allowable within predetermined design tolerances of the part dimensions. Example widths of the gap include 1/1,000 inch and 1/10,000 inch. In one embodiment, an outer radial surface 130 a of the sleeve 130 is flush with an outer surface of the drill collar 110 when no pressure P is applied to the sleeve 130.
When a pressure P is applied to an outer radial surface 130 a of the sleeve 130, the sleeve 130 presses against the seal members 140 and the sensor 120. In particular, the inner radial surface 130 b of the sleeve 130 presses against an outside radial surface 121 a of the coil portion 121. In one embodiment, when the pressure P is applied to the sleeve 130, the axial ends of the sleeve 130 are maintained substantially flush with the outer surface of the drill collar 110, and an axial center portion inward from the ends is compresses radially inward to contact the seal members 140 and the sensor 120. Since the gap 132 is very small, in the range of 1/1000 inch to 1/10,000 inch, the compression of the sleeve 130 is also very small and does not cause stress risers to form on the outer surface 130 a of the sleeve 130.
Since the hydrostatic pressure P is transferred to the seal members 140 and the sensor 120, the sleeve 130 is maintained in position, even during a drilling operation. In addition, the sleeve 130 is supported by the drill collar 110 via the sensor 120, while isolating the sensor 120 from fluids. The sensor 120 is thereby protected from damage from fluid in the drill bore and slippage of the sleeve 130. In addition, the compressive load of the hydrostatic pressure P further protects the sleeve 130 from tensile failure. In addition, the high level of pressure P against the sleeve 130 mitigates the effects of high coefficients of thermal expansion of non-conductive or non-metallic sleeves.
In one embodiment of the present disclosure, the sleeve 130 is a non-metallic sleeve, such as a high-temperature rated plastic or polymer sleeve. In one embodiment, a thickness of the sleeve 130 in a radial direction is at least 5% a diameter of the sleeve 130. For example, the thickness of the sleeve 130 may be between 5% and 20% of the diameter of the sleeve 130.
In one embodiment, the sleeve 130 presses directly against the sensor 120 when the pressure P is applied to the outer radial surface 130 a of the sleeve 130. In another embodiment, a non-conductive or non-metallic layer is formed on the sensor 120, such as around the coil portion 121 of the sensor 120, and the sleeve 130 presses against the non-conductive or non-metallic layer.
FIG. 3 illustrates a segment of drill pipe 300 according to one embodiment of the present disclosure. The segment of the drill pipe 300 includes a drill collar 310 and sleeve 330. As illustrated previously in FIGS. 1, 2A, and 2B, the sleeve 330 covers a sensor and an inside portion of the drill collar 310. In other words, the drill pipe 300, drill collar 310 and sleeve 330 may correspond to the drill pipe 100, drill collar 110, and sleeve 130 of FIGS. 1, 2A, and 2B.
The drill pipe 300 includes a raised portion 340 at each end of the sleeve 330. In one embodiment, the raised portion 340 includes a plurality of separated studs, platforms, plates, or pads 350 that extend radially outward from the drill collar 310 and are arranged around an outer circumference of the drill collar 310. In another embodiment, the raised portion is a single ring that extends around the circumference of the drill collar 310.
The raised portion 340 may be made of a material harder than the drill collar 310. For example, in one embodiment, the drill collar 310 is made of steel and the raised portion 340 is made of carbide. The raised portion 340 has a diameter D2 larger than a diameter D1 of the drill collar 310 and the sleeve 330. For example, in an embodiment in which the raised portion 340 is made of carbide pads 350, the outer surfaces of the carbide pads 350 correspond to a diameter D2 of the raised portion 340, and the diameter D2 of the raised portion 340 is greater than a diameter D1 of the sleeve 330. Accordingly, when the drill pipe 300 is located in the well bore, the raised portion 340 provides a standoff of the sleeve 330 from the drill bore wall. In one embodiment, a diameter D2 of the raised portion 340 is between approximately 1% and 10% greater than the diameter D1 of the sleeve 330.
An end of the sleeve 330 is separated from the raised portion 350 by a distance L1. The distance L1 is configured to ensure that the raised portion 340 provides a standoff for the sleeve 330 from a well bore wall. For example, when the raised portion 340 is larger, the distance L1 may be larger, or the sleeve 330 may be located farther from the raised portion 340. Conversely, when the raised portion 340 is smaller, the end of the sleeve 330 is located closer to the raised portion 340. In one embodiment, the distance L1 is less than a diameter D1 of the non-conductive sleeve.
FIG. 4 illustrates a method according to one embodiment of the disclosure. In block 401, a drill pipe including a drill collar, a sensor located around the drill collar, and a non-conductive or non-metallic sleeve located around the sensor and drill collar is provided into a well bore of an earth formation. The drill pipe may be the drill pipe 100 or 300 of FIGS. 1 and 3, respectively. The well bore may include fluid therein, such as drilling mud, water, petroleum, and other liquid. In block 402, a drilling operation is performed. Each of the providing the drill pipe into the well bore and performing the drilling operation may result in an increase in pressure on the sleeve of the drill pipe. As the pressure increases on the sleeve, the sleeve presses against the sensor and is supported by the drill collar. Since the sleeve is pressed against the sensor and the drill collar, the sensor is protected from damage from fluid in the drill bore and slippage of the non-conductive sleeve. In addition, the non-conductive sleeve is protected from tensile failure and the effects of high coefficients of thermal expansion.
In operation 403, a sensing operation is performed by the sensor during the drilling operation. Since the non-conductive sleeve is pressed against the sensor, the sensor is protected from damage and fluid exposure during the drilling operation. In embodiments in which the sleeve is a non-conductive or non-metallic sleeve, the sensing operation is improved relative to metallic or conductive sleeves that adversely affect sensing signals, such as electromagnetic signals.
According to embodiments of the present disclosure, a non-conductive or non-metallic sleeve is used to protect a sensor, preventing signal loss by the sensor. The sleeve is configured to press against the sensor during operation, such as under pressure in a well bore, to prevent slippage and form a hermetic seal over the sensor. Raised portions may also be provided at ends of the sleeve to further protect the sleeve from damage in the borehole.
Elements of the embodiments have been introduced with either the articles “a” or “an.” The articles are intended to mean that there are one or more of the elements. The terms “including” and “having” are intended to be inclusive such that there may be additional elements other than the elements listed. The conjunction “or” when used with a list of at least two terms is intended to mean any term or combination of terms. The terms “first” and “second” are used to distinguish elements and are not used to denote a particular order. The term “couple” relates to coupling a first component to a second component either directly or indirectly through an intermediate component.
It will be recognized that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.
While the invention has been described with reference to exemplary embodiments, it will be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

What is claimed is:

1. An apparatus for measuring a characteristic of an earth formation, comprising:

a drill collar configured to be inserted into a borehole of the earth formation;

an electromagnetic sensor on the drill collar; and

a non-conductive sleeve surrounding a circumference of the drill collar including the electromagnetic sensor and configured to press directly against the electromagnetic sensor.

2. The apparatus of claim 1, further comprising:

sealing members at axial ends of the non-conductive sleeve to form an airtight seal with respect to the drill collar and the non-conductive sleeve.

3. The apparatus of claim 2, wherein the sealing members are located radially between the non-conductive sleeve and the drill collar.

4. The apparatus of claim 1, wherein the non-conductive sleeve is a non-magnetic sleeve.

5. The apparatus of claim 1, wherein the non-conductive sleeve is made of a polymer.

6. The apparatus of claim 1, wherein the drill collar includes raised portions at axial ends of the non-conductive sleeve, the raised portions having diameters greater than a diameter of the non-conductive sleeve.

7. The apparatus of claim 6, wherein the raised portions are made of a material having a hardness greater than a hardness of the drill collar.

8. The apparatus of claim 6, wherein a distance from the ends of the non-conductive sleeve to the raised portions is less than a diameter of the non-conductive sleeve.

9. The apparatus of claim 1, wherein the non-conductive sleeve is configured to press against substantially an entire outer radial surface of the electromagnetic sensor.

10. The apparatus of claim 1, wherein the electromagnetic sensor is configured to press against the drill collar based on the non-conductive sleeve pressing against an outer radial surface of the electromagnetic sensor.

11. An apparatus, comprising:

a drill collar;

a sensor located around the drill collar; and

a non-conductive sleeve covering an entire outer surface of the sensor and configured to contact the outer surface of the sensor.

12. The apparatus of claim 11, wherein the non-conductive sleeve forms an airtight seal with the drill collar.

13. The apparatus of claim 12, further comprising sealing members located at axial ends of the non-conductive sleeve to press against the non-conductive sleeve to from the airtight seal with the drill collar.

14. The apparatus of claim 11, wherein the non-conductive sleeve is configured to compress inwardly in a radial direction toward the sensor when a predetermined pressure is applied to the non-conductive sleeve.

15. The apparatus of claim 14, wherein the predetermined pressure is one of a predetermined ranges of pressures corresponding to a pressure within a wellbore during a drilling operation.

16. The apparatus of claim 11, wherein the non-conductive sleeve is made of a high-temperature rated plastic.

17. The apparatus of claim 11, wherein the sensor is an electromagnetic sensor having a coil wound around the drill collar.

18. The apparatus of claim 11, wherein a thickness of the non-conductive sleeve is at least 5% of the diameter of the non-conductive sleeve.

19. The apparatus of claim 11, wherein the non-conductive sleeve has a smooth outer surface free of stress risers.

20. A method, comprising:

providing a drill collar in a wellbore, the drill collar including a sensor located on the drill collar and a non-conductive sleeve entirely covering the sensor; and

subjecting the non-conductive sleeve to a pressure to press the non-conductive sleeve against the sensor.

21. The method of claim 20, wherein subjecting the non-conductive sleeve to the pressure includes performing a drilling operation in the wellbore.

22. The method of claim 21, further comprising operating the sensor to obtain information about an earth formation while performing the drilling operation in the wellbore.