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Mini core drilling samples for high resolution formation evaluation on drilling cuttings samples

Mini core drilling samples for high resolution formation evaluation on drilling cuttings samples description/claims

This application is a continuation in part of U.S. Non-Provisional patent application Ser. No. 11/649,826 filed Jan. 5, 2007 which is a continuation in part of U.S. Non-Provisional patent application Ser. No. 10/711,467 filed Sep. 20, 2004 which claims the benefit of priority of U.S. Provisional Patent Application No. 60/481,447 filed Sep. 30, 2003, which are incorporated herein by reference in their entirety.

The present invention relates generally to methods and apparatus for evaluating the properties of a subsurface formation. More particularly, the present invention relates to methods and apparatus for obtaining a formation mini core in drilling samples for high resolution formation evaluation on drilling cuttings samples.

During the drilling of a well in a subsurface formation, mud or drilling fluid is circulated down hole and brings the drill cuttings of the strata penetrated being drilled. After the lag time, which comprises of the annular velocity and the depth of the well, the cuttings arrive to the surface. At the surface a sample catcher device, for example, such as that described in U.S. Pat. No. 6,386,026, may be used to capture the cuttings.

However, it is desirable to provide an improved method and apparatus for evaluating or storing the cuttings, for example captured as above, in a surface logging while drilling (SLWD) system.

It is an object of the present invention to obviate or mitigate at least one disadvantage of previous methods and apparatus for evaluating or storing cuttings.

The present method and apparatus provides a mini core for drilling cutting samples accumulated in the cups by sample catcher. It allows the explorations to obtain high resolutions formation evaluation on drilling cuttings samples.

The present method and apparatus may be used with samples collected using techniques known to one skilled in the art, for example the by a sample catcher as the one described in U.S. Pat. No. 6,386,026, which is, incorporated herein by reference.

The apparatus and method of the present invention provide extraction of a mini core from a sample, for example the cup where the sample catcher accumulates the drilling cuttings samples. By analyzing the strata in sequentially stored cuttings the high resolution formation evaluation on drilling cuttings samples is achieved. This leaves the remaining material practically undisturbed and allows for additional mini core extraction if desired.

The mini core apparatus or the present invention provides a tubular container which is adapted to sealingly receive a piston or cap.

In one embodiment, the tubular is a relatively narrow cylinder, with open ends. The thin wall cylinder may be rotated, for example by hand to be pressed into the sample (for example in a cup containing a wet sample of drilling cuttings). Once the cylinder is placed into the sample to the desired depth, the piston or cap is sealingly placed in the exposed open end of the cylinder to establish a vacuum. The mini core may then be pulled out from the sample.

In another embodiment, the tubular has at least one face which is substantially planar, for example the tubular having a semi-circular cross-section or a polygon. Preferably, the cross section is a quadrilateral, for example a rectangle or square. Because such shapes can not be freely rotated as was the case with a cylinder, other means may be used to assist pressing the tubular into the sample, for example vibrations such as microvibrations or micropulses of relatively high frequency and low amplitude, which may be applied to the tubular using apparatus and methods known to one skilled in the art. Once the tubular is placed into the sample to the desired depth, the piston or cap is sealingly placed in the exposed open end of the tubular to establish a vacuum. The mini core may then be pulled out from the sample.

The tubular may have a magnification means, for example a lens either affixed with or adapted to operatively one or more of the planar sides.

The mini core may be stored or analyzed in the tubular. The mini core may be stabilized by the addition of a stabilizing material, such as a stabilizing fluid known to one skilled in the art, for example a solution containing sugar, to enhance long term storage.

Alternatively, the mini core may be removed from the tubular for analysis, for example by squeezing it out on a flat tray for horizontal analysis. The micro layering can be visually separated before they are mixed as in conventional sample and the information is lost.

In a first aspect, the present invention provides an apparatus for making a mini core from a sample for analysis, having a tubular having open ends, adapted for penetrating the sample to a selected depth; and a piston adapted for sealing at least one of the open ends when the selected depth is reached.

In one embodiment, the tubular may be cylindrical or a quadrilateral, such as a rectangle, square etc. In one embodiment, the sample contains drilling cuttings.

In a further aspect, the present invention provides an apparatus for making a mini core from a sample with a sample container, including a tubular having a closed bottom and an at least partially open sidewall, adapted to be received in the sample container to sequentially receive the sample as the sample container receives the sample.

• Provisional Patent
• Utility Patent

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