CA2721292A1

CA2721292A1 - Core barrel assembly

Info

Publication number: CA2721292A1
Application number: CA 2721292
Authority: CA
Inventors: Gordon Burwash
Original assignee: G & O DIAMOND DRILLING CONTRACTORS LTD.
Current assignee: G & O DIAMOND DRILLING CONTRACTORS Ltd
Priority date: 2010-11-15
Filing date: 2010-11-15
Publication date: 2012-05-15

Abstract

A core barrel assembly having an outer tubular assembly and an inner tubular assembly, which is received within the outer tubular assembly. The outer tubular assembly includes a sacrificial coupling positioned at an upper end of a core barrel.
The sacrificial coupling has a landing ring seat to support a landing ring. The inner tubular assembly includes a sacrificial tubular extension positioned at a lower end of an inner tube and designed to collapse before damage is sustained by the core barrel and the inner tube.
A landing assembly is positioned below the sacrificial tubular extension. When the landing assembly of the inner tubular assembly engages the landing ring of the outer tubular assembly in a violent impact, any resulting damage is sustained by the landing ring seat of the sacrificial coupling and results in the collapse of the sacrificial tubular extension, thereby preventing damage from occurring to the core barrel or the inner tube.

Description

TITLE
[0001] Core Barrel Assembly FIELD

[0002] There is described a core barrel assembly used to take core samples which has been modified to avoid damage to a core barrel or an inner tube.

BACKGROUND

[0003] Core barrel assemblies have an outer tubular assembly that received an inner tubular assembly. The primary component of the outer tubular assembly is a core barrel which is approximately ten feet long. Positioned below the cord barrel is a coring bit, which may or may not have an associated reamer to enlarge the borehole made by the coring bit. A
landing ring is positioned in an upper portion of the core barrel to receive the inner tubular assembly. Positioned above the core barrel are one or more coupler subs, typically an adapter coupler and a locking coupling. The primary component of the inner tubular assembly is an inner tube. Positioned at the bottom of the inner tube is a landing assembly, which typically includes a core lifter case, a core lifter spring and a stop ring.

[0004] In most applications, the core barrel assemblies described above function as intended. However, in some applications, such as dry boreholes, the inner tubular assembly will strike the landing ring so violently that damage occurs to the core barrel, the inner tube or both. What is required is a core barrel assembly that will avoid damage to the core barrel and the inner tube.

SUMMARY

[0005] There is provided a core barrel assembly having an outer tubular assembly and an inner tubular assembly, which is received within the outer tubular assembly.
The outer tubular assembly includes a core barrel having an upper end and a lower end. A coring bit is positioned in the outer tubular assembly below the core barrel, such that a core formed by the coring bit passes into the core barrel. A sacrificial coupling is positioned at the upper end of the core barrel. The sacrificial coupling has a landing ring seat to support a landing ring. The inner tubular assembly includes an inner tube having an upper end and a lower end. A
sacrificial tubular extension is positioned at the lower end of the inner tube and designed to collapse before damage is sustained by the core barrel and the inner tube. A
landing assembly is positioned below the sacrificial tubular extension.

[0006] With the core barrel assembly, as described above, the landing assembly of the inner tubular assembly engages the landing ring of the outer tubular assembly in a manner which is not unlike that used in the prior art. However, in the event of a violent impact any resulting damage is sustained by the landing ring seat of the sacrificial coupling and results in the collapse of the sacrificial tubular extension. The sacrificial coupling and the sacrificial extension prevent damage from occurring to the core barrel or the inner tube.

[0007] When the inner tube is dropped, slips from the drillers grasp or over shoots the lower drilling tool, it strikes the core bit. The face of the core bit is struck and the core bit is left in the hole. When this occurs, the core bit has to be drilled out which is very slow and often costs a large amount of money to do. The sacrificial tubular extension described will collapse and save both the inner tube and drill bit from damage, which saves a lot of drill time and money.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:
FIG. 1 is an exploded view of a core barrel assembly.
FIG. 2, labelled as PRIOR ART, is an exploded view of a core barrel assembly currently in use.
FIG. 3 is a side elevation view, in section, of the core barrel assembly shown in FIG.1 with the inner tubular assembly inserted within the outer tubular assembly.
FIG. 4 is a side elevation view, in section, of the core barrel assembly shown in FIG. 2 with the inner tubular assembly inserted within the outer tubular assembly.

DETAILED DESCRIPTION

[0009] A core barrel assembly generally identified by reference numeral 10, will now be described with reference to FIG. 1 and FIG. 3, using the PRIOR ART core barrel assembly illustrated in FIG. 2 and FIG. 4, and generally identified by reference numeral 100 for comparison.

Structure and Relationship of Parts in PRIOR ART core barrel assembly 100 [0010] Referring to FIG. 2, there is illustrated PRIOR ART core barrel assembly 100.
Core barrel assembly 100 includes an outer tubular assembly 102 and an inner tubular assembly 104. Outer tubular assembly 102 includes a core barrel 106 that has an upper end 108 and a lower end 110. Upper end 108 of core barrel 106 has a landing ring seat 112 to support a landing ring 114. A coring bit 116 is positioned in outer tubular assembly 102 below core barrel 106 such that a core formed by coring bit 116 passes into core barrel 106.
Coring bit 116 includes a reamer 118. An adaptor coupler 120 and locking coupler 122 are positioned at upper end 108 of core barrel 106. An inner tube stabilizer 123 may be present below core barrel 106 [0011] Referring to FIG. 4, inner tubular assembly 104 is received within outer tubular assembly 102. Inner tubular assembly 104 includes an inner tube 124 that has an upper end 126 and a lower end 128. A landing assembly 130 is positioned at lower end 128 of inner tube 124. Landing assembly 130 includes a spring 132, a stop ring 134 positioned above spring 132 and a lifter case 136 positioned below spring 132 Operation of PRIOR ART core barrel assembly 100:

[0012] Referring to FIG. 4, inner tubular assembly 104 is received within outer tubular assembly 102. Inner tubular assembly 104 is released from surface and falls by force of gravity until landing assembly 130 of inner tubular assembly 104 engages landing ring 114 of outer tubular assembly 102. In most cases, there is liquid in the borehole that slows the descent of inner tubular assembly 104. However, problems have been experienced with the inner tubular assembly 104 descending too rapidly into boreholes having little or no liquid and the violent impact any results in damage being sustained by core barrel 106, inner tube 124 or both.

Structure and Relationship of Parts in core barrel assembly 10 [0013] Referring to FIG. 3, there is illustrated a core barrel assembly 10.
Core barrel assembly 10 has an outer tubular assembly 12 and an inner tubular assembly 14 within outer tubular assembly 12. Referring to FIG. 1, outer tubular assembly 12 has a core barrel 16 which has an upper end 18 and a lower end 20. A coring bit 22 is positioned in outer tubular assembly 12 below core barrel 16. Coring bit 22 may include a reamer 23. A
sacrificial coupling 24 is positioned at upper end 18 of core barrel 16 and has a landing ring seat 26 to support a landing ring 28.

[0014] Inner tubular assembly 14 has an inner tube 30 which has an upper end 32 and a lower end 34. A sacrificial tubular extension 36 is positioned at lower end 34 of inner tube 30 and is designed to collapse in response to a jarring force that exceeds a predetermined threshold. This may be accomplished by making sacrificial tubular extension 36 from a softer metal than core barrel 16 and inner tube 30. It may also be accomplished when sacrificial tubular extension 36 contains a breaking point 37 which will crumple under the jarring force. In the present embodiment both are present. A landing assembly 39 is positioned below sacrificial tubular extension 36 and engages landing ring 28 of outer tubular assembly 12. Landing assembly 36 includes a spring 38 with a stop ring 40 positioned above spring 38 and a lifter case 42 positioned below spring 38. In the event of a violent impact any resulting damage is sustained by landing ring seat 26 of sacrificial coupling 24 and results in collapse of sacrificial tubular extension 36.

Operation of core barrel assembly 10:

[0015] When inner tubular assembly 14 is dropped into place within outer tubular assembly 12, stop ring 40 of landing assembly 39 is caught by landing ring 28.
In the event of a violent impact damage is sustained by landing ring seat 26 of sacrificial coupling 24 of outer tubular assembly 12 and sacrificial tubular extension 36. This protects the more valuable components, core barrel 16 and inner tube 30 from damage and further prevents the coring bit 22 from being knocked off core barrel assembly 10.

[0016] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the 5 possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

[0017] The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. Those skilled in the art will appreciate that various adaptations and modifications of the described embodiments can be configured without departing from the scope of the claims. The illustrated embodiments have been set forth only as examples and should not be taken as limiting the invention. It is to be understood that, within the scope of the following claims, the invention may be practiced other than as specifically illustrated and described.

Claims

1. A core barrel assembly, comprising:
an outer tubular assembly, comprising:
a core barrel having an upper end and a lower end;
a coring bit positioned in the outer tubular assembly below the core barrel, such that a core formed by the coring bit passes into the core barrel;
a sacrificial coupling positioned at the upper end of the core barrel, the sacrificial coupling having a landing ring seat to support a landing ring;
an inner tubular assembly received within the outer tubular assembly, comprising:
an inner tube having an upper end and a lower end;
a sacrificial tubular extension positioned at the lower end of the inner tube and designed to collapse before damage is sustained by the core barrel and the inner tube; and a landing assembly positioned below the sacrificial tubular extension;
the landing assembly of the inner tubular assembly engages the landing ring of the outer tubular assembly, in the event of a violent impact any resulting damage is sustained by the landing ring seat of the sacrificial coupling and results in the collapse of the sacrificial tubular extension.

2. The core barrel assembly of Claim 1, wherein the coring bit includes a reamer.

3. The core barrel assembly of Claim 1, wherein the landing assembly comprises: a spring, with a stop ring positioned above the spring and a lifter case positioned below the spring.

4. The core barrel assembly of Claim 1, wherein the sacrificial tubular extension contains a breaking point which facilitates a collapse of the sacrificial tubular extension in response to a jarring force that exceeds a predetermined threshold.

5. The core barrel assembly of Claim 1, wherein the sacrificial tubular extension is made of a softer metal than the core barrel which facilitates a collapse of the sacrificial tubular extension in response to a jarring force that exceeds a predetermined threshold.