# US 6,295,867 B1 · Geological sample sub

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- Number: US 6,295,867 B1
- Document ID: US6295867B1
- Status: Granted
- Kind: B1
- Application number: 09/469,183
- Filed: 1999-12-21
- Granted: 2001-10-02
- Earliest claimed: 1998-12-21
- Inventors: Don F. Mahaffey
- Web page: https://patentgrep.com/patent/US6295867B1

## CPC

- E21B 43/086: {Screens with preformed openings, e.g. slotted liners (comprising porous materials E21B43/082)}
- E21B 17/16: Drill collars
- E21B 27/005: {Collecting means with a strainer}
- E21B 49/02: by mechanically taking samples of the soil
- E21B 49/08: Obtaining fluid samples or testing fluids, in boreholes or wells
- G01N 1/08: involving an extracting tool, e.g. core bit
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A sturdy tubular “sub” apparatus for collecting geological samples (Geological Sample-Sub or GSS) that may be entrained within a conventional drill string apparatus for conducting a drill-stem-test. The apparatus may be manufactured from conventional drill-collar stock and may be provided threads at each end of a standardized thread size so that it may be readily exchanged with or attached to other subs comprising the drill string apparatus. The drill string apparatus with the incorporated GSS may be lowered in a closed and empty state into a drilled hole whereupon it is packed off and the apparatus may be opened. A slit-like opening in the GSS permits entry of rock samples into the tubular apparatus, whereas baffles located within the apparatus near both ends prevent the escape of the samples as fluid in the hole rushes through the open drill string assembly.

## Claims

### Claim 1

A tubular device to collect geological samples from a conventional drilling assembly comprising:
a hollow tubular body having an outer surface, an inner surface and a passageway running therethrough;
an open first end having female threads disposed on said inner surface;
an open opposite second end having male threads disposed on said outer surface,
a plurality of perforations passing from said inner surface to said outer surface;
at least one slit opening passing from said inner surface to said outer surface;
a first baffle plate in the form of a perforated metal disc which is joinable to said inner surface of said tubular body proximate to said first end; and
a second baffle plate in the form of a perforated metal disc which is joinable to said inner surface of said tubular body proximate to said second end,
wherein said female threads and said male threads are configured in such a manner that said tubular device is readily connectable to a conventional drilling assembly.

### Claim 2 (depends on 1)

The tubular device in accordance with claim 1, wherein each of said plurality of perforations has a diameter of about 0.375 inches to about 0.50 inches.

### Claim 3 (depends on 1)

The tubular device in accordance with claim 1, wherein said plurality of perforations are disposed at about 6.0 inch intervals along said hollow tubular body and are radially displaced from one another about said tubular body.

### Claim 4 (depends on 1)

The tubular device in accordance with claim 1, wherein said at least one slit opening is in the form of a rectangular window of about 10.0 inches in length and about 2.0 inches inches in width.

### Claim 5 (depends on 1)

The tubular device in accordance with claim 1, wherein said hollow tubular body has an outer diameter of about 5.0 inches, an inner diameter of about 2.75 inches and a length of about 5.0 feet.

### Claim 6 (depends on 1)

A method for collecting geologic samples from a wellbore using the tubular device in accordance with claim 1, comprising the steps of:
joining said female threads of said first end of said tubular device to a corresponding male threaded end of a conventional drill string component and joining said male threads of said second end of tubular device to a corresponding female threaded end of a conventional drill string component in order to form a resulting drilling assembly having said tubular device entrained therein;
lowering said resulting drilling assembly into a wellbore in a closed configuration such that fluid flow through said assembly is prevented or minimized;
packing off the drilling hole with a packer assembly; and
opening said resulting drilling assembly such that a large pressure differential between the interior of said resulting drilling assembly and the surrounding wellbore creates an implosion of the walls of the wellbore and a fluid flow is enabled from the wellbore into and through said resulting drilling assembly and said tubular device,
whereby rock samples contained within the fluid flow entering said tubular device through said slit opening become entrapped between said first and second baffles of said hollow tubular body thereby providing said geologic samples.