GB2184835A

GB2184835A - Core container

Info

Publication number: GB2184835A
Application number: GB8531309A
Authority: GB
Inventors: Clive Kenneth Cornwall; Patricia Mary Dingwall
Original assignee: REDWOOD COREX
Current assignee: REDWOOD COREX
Priority date: 1985-12-19
Filing date: 1985-12-19
Publication date: 1987-07-01
Also published as: GB8531309D0

Abstract

A method and apparatus for preserving core samples within a sealed container in which the core sample is isolated from the ambient environment in order to prevent loss of fluid from the sample. The sample is enveloped in a liquid such as oil or brine which may be at elevated pressure, and the container has a one-way valve through its lid for introduction of fluid into the container.

Description

SPECIFICATION Core container This invention relates to a core container for use in the storage of rock samples.

In the development of hydrocarbon reservoirs rock samples, in the form of cores, are often taken and analysed in order to predict the likelihood and nature of deposits to be found in the vicinity of the sample site.

After analysis of the samples the cores are stored for possible analysis in the future.

At present cores are wrapped in a multilayered coating of plastic film, foil and wax before being placed in storage. Unfortunately, this coating does not retain the fluids held in the pores of the rock leading to dehydration of the sample after a year or more and subsequent structural decay of the rock.

It is an object of this invention to obviate or mitigate this disadvantage.

According to the present invention there is provided a method of preserving core samples with a sealed fluid filled container.

The fluid used to fill the container may be oil or brine.

The container for use in the storage of the core samples may comprise a vessel for receiving the core sample and a closure member for the vessel, locking means being provided for securing the closure member in a sealing fit on the vessel.

Preferably, the vessel is in the form of an elongate cylinder having one of its ends closed.

Preferably also, the vessel is of a material that is impervious and oil and brine resistant.

A suitable material may be any one of glass, a ceramics material, stainless steel or a plastics material.

Preferably also, a cradle for supporting a core sample to be received by the vessel is provided. The cradle may be formed from lengths of wire or rod of stainless steel or chrome plated steel.

Preferably also, the closure member for the vessel in in the form of a lid. The closure member may be of oil resistant plastics material or a material having similar properties.

Preferably also, the closure member is provided with sealing means to provide a seal between the closure member and the vessel.

The sealing means may be in the form of an O-ring of resilient material.

Preferably also, the closure member is provided with valve means for use in pressurising the container and for the introduction of fluid into the container.

Preferably also, the locking means is in the form of a locking ring for location on the open end of the vessel. The locking ring may be of similar material to the closure member and may be provided with engagement members for engaying with complementary engagement members provided on the closure member.

The engagement members on the ring may be in the form of outwardly extending lugs.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side view of a core container in accordance with the present invention; Figure 2 is a plan view of the locking ring of the core container of Fig. 1; and Figure 3 is a view from below of the lid of the core container of Fig. 1.

Referring to the drawings, a core container for use in the storage of rock samples comprises a vessel 1 for receiving a cylindrical core rock sample and a closure member 2 for the vessel 1, locking means 3 being provided for securing the closure member 2 in a sealing fit on the vessel 1.

The vessel 1 is in the form of an elongate cylinder having its lower end 4 closed. In this example the vessel 1 has a height of 30 mm and internal diameter of 130 mm for receiving core samples having a diameter of up to 115 mm.

The vessel 1 is of glass so as to be impervious and oil and brine resistant. As the core samples may be stored at above ambient pressure it is also necessary that the vessel can withstand an internal pressure of 250 p.s.i.g.

The open upper end 5 of the vessel 1 is provided with an outwardly extending annular flange 6. The upper surface of the flange 6 is provided with a raised offset lip (not shown) for engagement with a portion of the closure member 2.

The closure member 2 is in the form of a lid 7 which is circular in plan view and is made from an oil resistant plastics material.

An annular groove 8 is moulded in the lower face of the lid 7 to receive a resilient O-ring 9. When the lid 7 is secured on the vessel 1 the O-ring 9 is held in sealing contact with the raised lip on the flange 6 of the vessel 1.

In the centre of the lid 7 there is provided a one-way valve 10 through which fluid may be introduced into the vessel 1 and the vessel 1 pressurised.

Retaining means, in the form of inwardly extending moulded lugs 11 are provided to extend from the lower surface of the lid 7. The lugs 11 engage complementary outwardly extending lugs 12 which are provided on the locking means 3.

A radially extending handle 14 is provided on the lid 7 to facilitate the removal and fitting of the lid 7. An indicating arrow (not shown) is provided on the handle to indicate to an operator the direction the lid should be turned to engage with the locking means 3.

The locking means 3 is in the form of lock ing ring 13 which is manufactured as a single moulding of a similar material to the lid 7. An indicating arrow (not shown) is provided n a handle 17 of the locking ring and indicates to an operator which way the ring 13 should be rotated for removal from the vessel 1.

A stainless steel wire cradle 15 is provided to support a core sample to be placed in the vessel 1. Hinged loops 16 are provided at the upper end of the cradle 15 for lifting the cradle 15 into, and out of, the vessel 1.

In use, a core sample tQ be stored is placed in a cradle 15 and then lowered into the vessel 1 which has been partially filled with oil.

After checking that the core sample is completely immersed in the oil the lid 7 is secured to close the vessel 1. If desired the oil level or the internal pressure of the container may be raised by introducing further oil through valve 10 in the lid 7.

Before shipping or storage the container is placed in a foam lined crate for additional security.

In this way a core sample may be preserved for a long period of time, without dehydration and subsequent structural decay of the rock.

Modifications and improvements may be made without departing from the scope of the invention.

Claims

1. A method of preserving a core sample, comprising emveloping the core sample in fluid within a container and sealing the container against passage of fluid.

2. A method according to Claim 1, wherein the core sample is enveloped in the fluid by inserting the core sample into the container, sealing the container against outflow of fluid and thereafter introducing fluid into the container.

3. A method according to Claim 1 or 2, wherein the fluid enveloping the core sample is at greater than ambient pressure.

4. A method according to any one of the preceding Claims, wherein the fluid enveloping the core sample is oil or brine.

5. A method according to any one of the preceding Claims, wherein the core sample is disposed in a supporting cradle within the container.

6. A method according to any one of the preceding Claims, wherein the container com prises a fluid-impermeable vessel having a fluid-impermeable closure member in sealing engagement with the vessel.

7. A method according to Claim 6, wherein the closure member has a one-way valve for introduction of fluid therethrough into the ves sel.

8. A method of preserving a core sample substantially as hereinbefore described with reference to the accompanying drawings.

9. A container for use in preserving core samples, comprising a vessel of fluid-imperme able material having an opening for receiving a core sample, a closure member of fluid-impermeable material adapted to close said opening, sealing means between the vessel and the closure member for preventing egress of fluid from the vessel when the closure member is in position on the vessel, and a oneway valve in the closure member for introduction therethrough of fluid into the vessel.

10. A container according to Claim 9, including a cradle disposed within the vessel for supporting the core sample.

11. A container for use in preserving core samples, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.