Boring or penetrating the earth – Processes – Sampling of earth formations
Reexamination Certificate
2002-06-21
2004-01-27
Tsay, Frank (Department: 3672)
Boring or penetrating the earth
Processes
Sampling of earth formations
C175S004000, C175S249000
Reexamination Certificate
active
06681873
ABSTRACT:
TECHNICAL FIELD
The present invention relates in general to the drilling of core samples, and in particular to the stabilization of the recovered core in a core barrel.
BACKGROUND INFORMATION
Cores (drilling core samples) acquired in the subsurface of the earth are generally recovered with a core barrel that either has a disposable inner barrel or a disposable inner barrel liner. (For the purposes of the present invention, the distinction is not material, and “inner barrel,” will be used to refer to both a disposable inner barrel and a disposable inner barrel liner.) At the surface, the core barrel is separated from the coring assembly and placed on the drilling rig floor or other work area.
If the core material is unconsolidated, the core is “stabilized” to prevent mechanical damage caused by handling and shipment. Core stabilization may either be by freezing with dry ice to artificially consolidate the core, or by filling an annular space of the core barrel with a non-reactive core stabilizing compound, for example, epoxy or gypsum.
FIG. 1
illustrates, in transverse cross section, an inner barrel
102
, enclosing a core sample
104
. Because core sample
104
does not completely fill inner barrel
102
, a void space
106
remains in an interior of inner barrel
102
, which may be filled to prevent core sample
104
from moving within inner barrel
102
, to prevent damage to the core by handling and shipment of the samples. In both the epoxy fill or gypsum fill techniques, the inner barrel, which may be thirty feet or more in length, is first sectioned into approximately one meter segments. Each segment is placed on a rack in a near horizontal position to drain any drilling fluid, or mud, from the inner barrel. The base of the segment is then stabilized. After the base is stabilized, the segment is placed in a near vertical position and the entire segment stabilized. Thus, the present methodologies entail substantial handling of the inner barrel and enclosed core sample, and the sample is thus susceptible to mechanical damage caused by vibration, jarring, or other movement.
Thus, there is a need in the art for apparatus and methods that reduce the risk of core damage and the stabilization of core samples in inner barrels. In particular, there is a need in the art for techniques that reduce the movement and handling of the inner barrel, and the contained core in the stabilization process, and, which advantageously permits stabilization of the full length of the inner barrel without the need for segmenting the inner barrel and contained core sample.
SUMMARY OF THE INVENTION
The present invention provides a core stabilization mechanism which stabilizes the core along the entire length of the inner barrel. At each one of a plurality of positions spaced axially along the inner barrel, a set of ports are provided. The ports are displaced circumferentially about the inner barrel at each axial location. One port of the set provides a vent port, and the others provide drainage and injection ports. During the stabilization process, air, or other gas, is injected into the vent port, via a gas manifold attached thereto, thereby effectuating the drainage of the drilling mud from the drainage/injection ports. After the drilling mud has been drained, a core stabilizing compound is simultaneously injected into all of the drainage/injection ports, at each position along the length of the inner barrel. An injection manifold is attached to a drain/inlet coupled to each drainage/injection port. The injection manifold is fed from a stabilizing compound supply. The core stabilizing compound is then allowed to cure. After curing, the inner barrel, with the stabilized core contained therein may be sectioned into segments for ease in handling and transport.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
REFERENCES:
patent: 4071099 (1978-01-01), Hensel, Jr.
patent: 4371045 (1983-02-01), McGuire et al.
patent: 4587857 (1986-05-01), Bush
patent: 4825963 (1989-05-01), Ruhle
patent: 6006844 (1999-12-01), Van Puymbroeck et al.
Core Laboratories Global N.V.
Newberger Barry S.
Tsay Frank
Winstead Sechrest & Minick P.C.
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