GB2133894A - Determining condensable content in drilling rock samples - Google Patents

Abstract

Apparatus for determining water, oil and other condensable content in a drilling core or rock or like sample. The apparatus comprises a heat-insulated chamber 1 having a heat-insulated lid 5 and containing seats 16 for receiving a plurality of cartridge-like closed containers 23 in each of which a sample to be tested is placed. The chamber 1 is heated to a selected and controlled elevated temperature to effect fractional distillation of part of the contents to be determined. Each container 23 has an outlet which communicates through an outlet 18 in the respective seat 16 and passing through a drainable water-cooled jacket 19 to effect condensation of the selected fraction. <IMAGE>

Description

SPECIFICATION Apparatus for determining water, oil and other condensable content in a drilling core or other sample of rock or shale or like material The invention relates to apparatus for determining water, oil and other condensable content in a drilling core or other sample of rock or shale or like material and is particularly concerned with apparatus for performing an analysis by the retort method.

In a conventional analysis by the retort method, the drilling core or other sample is heated in a retort in steps of increasing temperature so that first water is vaporised and is then distilled and collected and then oil and other condensable contents are liquefied at one or more elevated temperatures and collected, thereby to enable the volume of water, oil and other condensable contents to be measured. Such an analysis has hitherto required large retorts to enable the analysis to be performed and has taken many hours or days to perform. An object of the invention is to provide compact apparatus whereby an analysis of a sample, or the simultaneous analyses of a plurality of samples under the same temperature conditions, can be performed considerably more quickly, than hitherto, for example in under one hour.

According to the invention, the apparatus comprises a normally closed heat-insulated chamber having an opening therein providing access to the interior of the chamber and a heatinsulated closure member for said opening; at least one seat within the chamber for receiving the lower end of a respective cartridge-like container, constituting a retort, into which a drilling core, ground drilling core or other sample is to be placed, the or each container being closed in use except for an outlet at its lower end and which communicates, in use, with the or a respective seat; a discharge pipe extending downwardly from the seat, or a plurality of discharge pipes extending downwardly one from each said seat, where there is a plurality of seats, said discharge pipe or pipes passing through a bottom or other lower wall of the chamber; heating means for heating the interior of the chamber to a selectable known controllable elevated temperature; the lower end of the or each discharge pipe being dischargeable into a or a respective collection and measuring vessel, and a jacket surrounding the or each discharge pipe between the position therein at which it leaves the chamber and its discharge end, said jacket having an inlet and an outlet for the circulation therethrough of a coolant and drainage means for removing coolant from the jacket.

The apparatus as set out in the immediately preceding paragraph enables the, or all the containers simultaneously where a plurality of seats is provided, to be heated to a first elevated temperature (e.g., 2500C) at which the sample within the container or containers is heated to vaporise the water content of the sample, while water or other coolant is being circulated through the jacket to effect distillation of the water content which is collected and measured in the or each vessel, and then for the sample within the container or containers to be heated to at least one higher temperature (e.g., 6500C) with the coolant jacket drained, thereby to allow oil to flow from the or each container, through the or the respective discharge pipe to the or another collection and measuring vessel.The container or containers may be heated to other elevated temperatures to evaporate other condensable liquids. For example, an intermediate temperature of say, 4500C may be selected to evaporate condensable content after the water content has been evaporated and before an oil content is evaporated. The lower end of the or each container and the or each seat are conveniently shaped to interfit closely one with the other.

The outlet and the lower end of the or each container is conveniently tubular and interfits with a small clearance with the inlet to the discharge pipe in the or the respective seat when the chamber is cold, the outlet and the inlet to the discharge pipe expanding differently at elevated temperatures to effect a seal therebetween.

Where a plurality of seats is provided it is important that one of said containers is placed on each seat regardless of whether the container is being used or not, i.e., whether or not it is empty, to avoid loss of heat through the discharge pipe leading from each seat.

The heating means is conveniently an electric heating element mounted within the chamber and which is controllable to heat the interior of the chamber to a selected elevated temperature determined by a thermostatic temperature probe positioned within the chamber.

The chamber may conveniently comprise an inner open box, of which the bottom supports the seat or seats and through which the or the respective discharge pipe passes; an outer tubular casing spaced around the walls and bottom of the box, the tubular space between the box and the outer casing being packed with heat insulating material and the upper rim of the box extending upwardly beyond the upper end of the casing, and a lid hinged along one edge thereof to the casing and having a downwardly-facing deformable cushion of heat-insulating material therein which, when the lid is closed, is abutted by and forms a peripheral seal against the upper edges of the walls of the box, the box being free to expand upwardly, when heated, relative to the casing into tighter abutment with the deformable cushion in the lid, the lid having a first part of catch means thereon engageable with a co-operable second part of the catch means on the casing, thereby when so engaged to hold the lid closed with respect to the casing. Preferably one or other part of the catch means includes an overcentre toggle member operable to pull the lid downwardly into engagement with the casing and thereby to effect the seal between the upper edges of the walls of the box with the cushion on the lid.

The invention also includes a closable cartridge-like container having a lower end shaped to interfit closely with the corresponding seat in the chamber in the apparatus and having an outlet which communicates with the discharge pipe leading from the seat, as aforesaid. The container is conveniently of cylindrical shape and has a removable end closure cap which makes screwthreaded and sealing engagement with the container. Conveniently the upper end of the container or the cap thereof may be provided with a lifting eye or equivalent means, whereby the container can be placed on and removed from the seat by means of a lifting hook, tongs or other tool.

The invention also includes the method of placing the drilling core, ground drilling core sample ot other sample in a closed container having an outlet at its lower end; placing the container on a seat in a closed heat-insulated chamber, the seat having a discharge pipe extending downwardly from the chamber to a collecting and measuring vessel; heating the interior of the chamber and therefore the container therein to a first temperature (e.g. 2500C) at which the water content in the sample is vaporised; cooling the discharge pipe to below 1 000C to condense the water content and collecting and observing the volume of the resulting water in said measuring vessel; then heating the interior of the chamber and therefore the container therein to at least one elevated temperature (e.g., 6500 C) at which the oil content will flow from the container to the discharge pipe without cooling the latter and thereby to collect the oil content in the or another measuring vessel and observing the volume of oil collected.

The container may be heated to other elevated temperatures to evaporate other condensable liquids. For example an intermediate temperature of, say, 4500C may be selected to evaporate a condensable content after the water content has been evaporated and before an oil content is evaporated.

The discharge pipe may be arranged to be cooled to below 1 000C by providing a cooling jacket around the discharge pipe and circulating coolant through the cooling jacket. Conveniently the coolant water and the cooling jacket is drained of the water by stopping the water supply and opening a drainage cock, when oil is to be collected from the sample by raising the temperature within the chamber and therefore of the container to said elevated temperature.

Preferably a plurality of containers each having a drilling core or other sample are tested simultaneously by heating said containers in a chamber common to all containers and seats therefor. As stated hereinbefore, where a plurality of seats is provided it is important that a container is placed on each seat, even where a container is empty, as otherwise there would be a loss of heat through the discharge pipe leading from the seat.

An example of the apparatus in accordance with the invention is now described with reference to the accompanying drawings in which: Figure 1 is a perspective view from the front and one end, showing the lid partly open and part of the chamber and cooling jacket broken away.

Figure 2 is a perspective view from the rear and the other end, and Figure 3 is an exploded view of a container; its seat and associated discharge pipe also shown in Figure 1; but drawn to a larger scale.

Referring to the drawings, the apparatus comprises a stainless steel open-topped box 1.

This is positioned with peripheral clearance in a casing 2 having four walls and a lower bottom wall 3 spaced from the bottom of the box 1. The peripheral space between the casing 2 and the box 1 is packed with a heat-insulating material 4.

The casing 2 has a lid 5 hinged at 6 to the casing and also packed with heat-insulating material 7.

The heat-insulating material 7 forms a resilient cushion which is abutted by the upper edges of the walls of the box 1 when the lid 5 is closed. The front wall of the casing 2 carries a catch member 8 which is engageable with a hook 9 on the front edge of the lid 5 and includes a toggle operating lever 10 which is operable to tighten the catch member 8 when the latter has been engaged with the hook 9 and so pull the lid 5 downwardly so as to effect a tight seal between the cushion 7 of the lid 5 and the upper edges of the walls of the box 1.

The box 1 and the lid 5 thus define a closed heatinsulated chamber 11.

The interior of the chamber 11 is heated by one or more electrical heating elements 1 2 positioned within the chamber and connected to an eiectricity supply by a control box 1 3 mounted on the outside of the casing 2. The control box 13 contains a power pack of which the circuit (not shown) includes a control knob 14 which can be set to provide a selected elevated temperature. In this embodiment the temperature may be adjustable to produce a temperature within the chamber 11 up to 7000 C. The temperature is controlled thermostatically by a probe 1 5 (see Figure 2) extending through the casing 2 and into the box 1 and connected to the circuit of the power pack within the control box 13.As the interior of the box 1 is, in use, heated to a high temperature up to 7000C in this example, the box 1 becomes extremely hot compared with the wellinsulated casing 2 and it therefore expands. This expansion is accommodated by movement of the walls of the box 1 within the heat-insulating material 4 resulting in movement of the upper edges of the walls of the box 1 engaging the cushion 7 of the lid 5, and, where the movement is upward, compressing the cushion 7 to improve the seal and so prevent the escape of hot gases from within the chamber 11. Although the casing 2 and the lid 5 are well-insulated, the lid does become hot to touch during use and so a knob 35 of wood or other heat-insulating material is provided to enable the lid 5 to be opened and closed.

The bottom of the box 1 supports a plurality of seats 1 6 mounted side-by-side within the box 1.

In this example there are ten seats 1 6 (see Figure 3) spaced apart in the length of the box 1. The seats 1 6 have upper seating faces 1 7 of part sphericai concave shape and each face 1 7 has at its centre a discharge orifice communicating with a discharge pipe 1 8 passing downwardly through a hole in the bottom of the box 1 in a gas-tight manner. The discharge pipes 1 8 are spaced apart from each other and pass through a common cooling tank or jacket 1 9 mounted beneath the casing 2 and the box 1 and therefore the discharge pipes 1 8 act as condenser tubes.The cooling tank 19 has an inlet pipe connection 20 and an outlet pipe connection 21, whereby a coolant, for example a normal domestic water supply, can be circulated through the tank 1 9 to cool the discharge pipes 1 8. The pipes 1 8 extend through the bottom of the tank 19 in water-tight joints. The tank 19 also has a drain-cock 22 by which the tank 1 9 is drained after the water supply through the pipe connections 20, 21 has been cut-off (see Figure 2).

The drilling cores, ground core samples or other samples, of rock, shale or like material to be tested are inserted into cartridge-like containers 23, constituting retorts, sometimes called "core sample cups" or "bombs". Each container 23 is a steel cylinder (see Figure 3) having a bottom end wall 24, which is of convex part-spherical shape, machined to mate with the concave seating face 1 7 of a seat 16. The bottom end wall 24 has a short central outlet pipe 25 which is located in the discharge orifice in the seat 1 6. There is a small clearance between the outer peripheral surface of the outlet pipe 25 and the periphery of the orifice in the seat 1 6 when the container 23 and the seat 1 6 are cold, i.e., at ambient temperature.The clearance is for example a few thousandths of an inch, i.e., less than 0.1 mm. When the container 23 becomes heated to an operational elevated temperature, the outlet pipe 25 expands by a differentially greater amount that the seat 1 6 and a seal is effected between the outlet pipe 25 and the seat 1 6. Each container 23 has a cap 26 which is screwed to the upper end of the container. The cap 26 contains a heat-resistant seal 27 ensuring a gas-tight seal when the cap 26 bas been tightly screwed onto the container 23. The cap 26 has a lifting eye 28 enabling the container to be placed into the chamber 11, when the latter is still hot from a previous test, and to be lifted from the chamber 11 after a test.The containers 23 are supported upright within the chamber 11 when they are resting on their respective seats 1 6 by a removable plate 29 having apertures 30 therein to receive the containers 23. The plate 29 rests on a ledge 31 within the box 1.

When a drilling core, ground core sample, or other sample is to be tested, it is placed in an open container 23. Preferably the drilling core is first reduced to a suitable particle size by grinding it to enable the contents of the core sample to be more easily and quickly extracted. Before the ground core sample is introduced into the open container, a wire mesh insert 35 is pushed into the container 23 to rest just above the mouth of the pipe 25. The insert 35 is pushed down by a tool (not shown) having a lower end which is of convex shape to encourage the disc 35 to be deformed to concave shape as it is being pushed down on to the lower end of the container. The tool is then removed and the ground core sample is introduced. This is not compressed as the sample should remain loose in the container to aid extraction of the oil and other contents.The wire mesh insert 35 holds the core sample from blocking the mouth of the pipe 25. The cap 26 containing the seal 27 is then tightly screwed onto the container and the latter is placed on a seat 1 6 and the lid 5 is closed and the toggle-actuated catch is applied. Cooling water is circulated through the tank 1 9 after first ensuring that the drain-cock 22 is closed. The lower end of the relevant discharge pipe 1 8 is fitted into one hole of a two-hole bung 32 which is fitted into a measuring cylinder or vessel 33. The second hole 34 in the bung 32 is a vent to enable air to be displaced from the measuring cylinder 33.

The control knob 14 is set to 2500C and the heater element 12 is switched on. The latter heats the container 23 and the water content of the core sample, or other sample, being tested is vaporised and is condensed in the relevant discharge pipe 1 8 by the cooling water circulated through the tank 19 and is collected and measured in the graduated measuring cylinder 33 and a reading of volume is taken and recorded.

Then the temperature is increased by readjustment of the knob 14 to, say, 4500C at which temperature further impurities, but not oil, are expelled from the container and condensed.

Then the supply of cooling water is stopped and the drain-cock is opened, thereby emptying the tank 19.

Then the temperature is set to an elevated temperature at which oil will be separated, for example 6500C. The chamber 11 will be maintained at this temperature thermostatically under the control of the probe 1 5. Oil will separate at this elevated temperature and will flow through the discharge pipe 18, which rapidiy becomes hot as the tank 19 is now empty, into the measuring cylinder 33, the oil floating on top of the previously collected condensate. An oil volume reading is taken and recoded. If preferred a different measuring cylinder 33 can be used for collecting the oil. As the temperature can be accurately reset, the chamber 11 can be heated in stages to successive elevated temperatures at which oil will be discharged, whereby the oil fraction content at each of two or more known elevated temperatures can be measured.

The residual ash is available for analysis, if required, e.g., for pollution detection purposes when the waste contains undesirable materials, such as metals of an injurious nature.

As in this example there are ten seats 1 6 positioned side-by-side up to ten different core samples or other samples, can be tested simultaneously under the same temperature, which is uniform through the chamber 11. Of course, the ten seats 1 6 are illustrated only by way of example. A greater or smaller number of seats 1 6 and associated discharge pipes 1 8 may be provided in alternative forms of the apparatus.

There are conveniently two elements 12 positioned one at each side of the row of seats 1 6 and containers 23, As hereinbefore explained, containers must be placed on each seat whether or not the container is empty.

The apparatus provided by this invention enables a core analysis to be performed in under one hour, for example in 30 to 45 minutes, whereas with existing and much bulkier retort test apparatus the time taken for performing only a single analysis was several hours or days.

Furthermore, a plurality of core samples, or other samples can be tested under uniform temperature conditions simultaneously.

Claims (15)

1. Apparatus comprising a normally-closed heat-insulated chamber having an opening therein providing access to the interior of the chamber and a heat-insulated closure member for said opening; at least one seat within the chamber for receiving the lower end of a respective cartridgelike container, constituting a retort, into which a drilling core or other sample is to be placed, the or each container being closed in use except for an outlet at its lower end and which communicates, in use, with the or a respective seat; a discharge pipe extending downwardly from the seat, or a plurality of discharge pipes extending downwardly one from each said seat, where there is a plurality of seats, said discharge pipe or pipes passing through a bottom or other lower wall of the chamber; heating means for heating the interior of the chamber to a selectable known controllable elevated temperature; the lower end of the or each discharge pipe being dischargeable into a or a respective collection and measuring vessel, and a jacket surrounding the or each discharge pipe between the position therein at which it leaves the chamber and its discharge end, said jacket having an inlet and an outlet for the circulation therethrough of a coolant and drainage means for removing coolant from the jacket.

2. Apparatus as claimed in Claim 1 in which the lower end of the or each container and the or each seat are shaped to interfit closely one with the other.

3. Apparatus as claimed in Claim 2 in which the outlet at the lower end of the or each container is tubular and interfits with a small clearance with the inlet to the discharge pipe in the or the respective seat when the chamber is cold, the outlet and the inlet to the discharge pipe expanding differentially at elevated temperatures to effect a seal therebetween.

4. Apparatus as claimed in any preceding claim in which the heating means comprises an electric heating element mounted within the chamber and controllable to heat the interior of the chamber to a selected elevated temperature determined by a thermostatic probe positioned within the chamber.

5. Apparatus as claimed in any preceding claim in which the chamber comprises an inner open box, of which the bottom supports the seat or seats and through which the or the respective discharge pipe passes; an outer tubular casing spaced around the walls and bottom of the box, the tubular space between the box and the outer casing being packed with heat insulating material and the upper rim of the box extending upwardly beyond the upper end of the casing, and a lid hinged along one edge thereof to the casing and having a downwardly-facing deformable cushion of heat-insulating material therein which, when the lid is closed, is abutted by and forms a peripheral seal against the upper edges of the walls of the box, the box being free to expand upwardly, when heated, relatively to the casing into tighter abutment with the deformable cushion in the lid, the lid having a first part of catch means thereon engageable with a co-operable second part of the catch means on the casing, thereby when so engaged to hold the lid closed with respect to the casing.

6. Apparatus as claimed in Claim 5, in which one or other part of the catch means includes an over-centre toggle member operable to pull the liquid downwardly into engagement with the casing and thereby to effect the seal between the upper edges of the walls of the box with the cushion on the lid.

7. A closable cartridge-like container for use with the apparatus according to any preceding claim and having a lower end shaped to interfit closely with the corresponding seat in the chamber in the apparatus and having an outlet which communicates with the discharge pipe leading from the seat.

8. A container as claimed in Claim 7 of cylindrical shape and having a removable end closure cap which makes screw-threaded and sealing engagement with the container.

9. A container as claimed in Claim 8 in which the upper end or the cap thereof is provided with a lifting eye or equivalent means to enable the container to be placed on or removed from its seat.

10. Apparatus constructed and arranged substantially as described herein and shown in the accompanying drawings.

11. A method of placing a drilling core, ground drilling core sample or other sample in a closed container having an outlet at its lower end; placing the container on a seat in a closed heat-insulated chamber, the seat having a discharge pipe extending downwardly from the chamber to a collecting and measuring vessel; heating the interior of the chamber and therefore the container therein to a first temperature at which the water content in the sample is vaporised; cooling the discharge pipe to below 1 O00C to condense the water content and collecting and observing the volume of the resulting water in said measuring vessel; then heating the interior of the chamber and therefore the container therein to at least one elevated temperature at which the oil content will flow from the container to the discharge pipe without cooling the latter and thereby to collect the oil content in the or another measuring vessel and observing the volume of oil collected.

1 2. The method according to Claim 11 in which the container is heated to other elevated temperatures to evaporate other condensable liquids,

13. The method according to Claim 11 or 12 in which the or each discharge pipe is cooled to below 1000C by providing a cooling jacket around the discharge pipe or pipes and circulating coolant through the cooling jacket.

14. The method according to Claim 13 in which the coolant is water and the cooling jacket is drained of water after stopping the water supply by opening a drainage cock.

15. The method according to any of Claims 11-14 in which a plurality of drilling cores or said samples are heated simultaneously each in one of a plurality of containers and seat therefor in a common chamber.