CA2675478A1 - Core sample forming mill - Google Patents

Abstract

A core sample forming mill having a tubular body with an attachment end, a cutting end, an exterior surface and an interior surface defining an interior bore. A plurality of cutters are positioned at the cutting end for cutting a core sample. Core forming rods are positioned in spaced relation around the interior surface at the cutting end to compact and form the core sample.

Description

TITLE
[0001] Core Sample Forming Mill FIELD

[0002] The present invention relates to an earth-boring mill that is used to extract core samples.

BACKGROUND

[0003] United States Patent 5,568,838 (Struthers et al) discloses an example of a drill bit with coring capabilities. This drill bit offers interchangeable placement and retrieval of coring inner tube assemblies and drilling plug assemblies for drilling ahead, it also provides the capability of alternately coring and drilling without tripping the drill string and for taking extended-length small diameter cores. However, it is doubtful about the effectiveness of the above drill bit in forming core samples.

SUMMARY

[0004] According to the invention, there is provided a core sample forming mill with core forming rods. This core sample forming mill can simultaneously conduct the operations of coring and forming of core sample with high effectiveness. The core sample-forming mill allows an operator to recover a sample of earth in subterranean formations by rotating mill and pressing into the formation. In another way, fluid could be pumped around the mill to cool cutting edges and facilitate forming of the sample. The sample is forced through the centre of the mill and is retrieved as the mill is pulled from the formation.

[0005] The core sample forming mill, as will hereafter be further described, includes a tubular body having an attachment end, a cutting end, an exterior surface and an interior surface defining an interior bore. A plurality of cutters are positioned at the cutting end. Core forming rods are positioned in spaced relation around the interior surface at the cutting end.
The rods serve to compact and shape a core entering the interior bore.

[0006] The core sample forming mill is unique to form the core sample. This is achieved by using hardened rods to literally shape the sample much like a sculptor forms a clay pot with his fingers. As the mill turns and fluid is washed through the mill, a smooth and precise sample is produced. The sample forming concept with hardened rods is also used on the outside of the mill to keep the outer wall of the "well" from falling in. This allows easier retrieval of mill and sample.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] 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 a longitudinal section view of the core sample forming mill.
FIG. 2 is a side elevation view of the core sample mill of FIG. 1.
FIG. 3 is a bottom plan view of the cutting end of the core sample forming mill of FIG.1.

DETAILED DESCRIPTION

[0008] The core sample forming mill, according to the invention, generally identified by reference numeral 10, will now be described with reference to FIG.1 through 3.

Structure and Relationship of Parts:

[0009] Referring now to FIG. 1, core sample forming mill 10 has a tubular body 20.
Tubular body 20 having an attachment end 22, a cutting end 24, an exterior surface 26 and an interior surface 28 defining an interior bore 30. A plurality of cutters 42 are mounted on a cutter face 32 at a cutting end 24. Threads 36 for attaching to a drill string (not shown) are positioned at attachment end 22. Core forming hardened rods 34 are positioned in-spaced relation around interior surface 28 at cutting end 24. The core forming hardened rods 34 serve to form a core within interior bore 30. When the mill 10 is rotated, the direction of drilling 4 is just opposite to movement 2 of core sample. Movement of the core sample within interior bore 30 is guided by guide ribs 40.

[0010] Referring now to FIG 2 a pair of external well forming rods 38, are arranged in longitudinal parallel spaced relation around exterior surface 26 at the cutting end 24. The external well forming rods 38 compact and shape earth of subterranean formation surrounding mill 10 from subterranean formation.

[0011] Referring now to FIG 3 cutters 42 mounted on cutter face 32 at cutting end 26, are made from polycrystalline diamond. Cutters 42 are mounted in precisely machined and located cutter supports 46. The cutters 42 are tapered and are symmetrically placed about a circumference of cutter face 32 to bore through the formation efficiently.

Operation:

[0012] Referring to FIG 3, when core sample forming mill 10 is rotated, cutter face 32, contacts earth in subterranean formation, and polycrystalline diamond cutters 42, cut a core sample which enters interior bore 30 of the mill 10. As this core sample begins to enter interior bore 30, internal core forming rods 34 compact and shape the core sample. Referring to FIG. 2, external well forming rods 38 compact and shape earth surrounding body 20. As a result, the core sample is forced into interior bore 30 of mill 10, while being compacted and formed by core forming rods 34. As the mill 10 is pulled from the subterranean formation, the core sample of earth is retrieved form the formation. It is preferred that fluid be pumped around mill 10 to cool cutting face 32 and facilitate forming of the core sample. As the mill turns and fluid is washed through the mill, a smooth and precise sample is produced. The compaction of the well by external well forming rods 38 keeps the outer walls of the well from falling in and facilitates easier retrieval of the mill and sample.
Variations:

[0013] There are some variations to the invention without beyond of the spirit of the invention. For example, the arrangement, shape and material of the polycrystalline diamond cutters 42, as shown in FIG 3 could be changed. The arrangement or shape of the core forming rods 34, as shown in FIG 3 could also be changed.

[0014] 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 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.

[0015] 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 (2)

1. A core sample forming mill, comprising:
a tubular body having an attachment end, a cutting end, an exterior surface and an interior surface defining an interior bore;

a plurality of cutters at the cutting end; and core forming rods in parallel spaced relation around the interior surface at the cutting end wherein the rods serve to compact and shape a core entering the interior bore.

2. The core sample forming mill of claim 1, wherein there are external well bore forming rods positioned in parallel space relation around the exterior surface at the cutting end.