GB2369838A - Method and apparatus for cleaning drill cuttings - Google Patents
Method and apparatus for cleaning drill cuttings Download PDFInfo
- Publication number
- GB2369838A GB2369838A GB0029987A GB0029987A GB2369838A GB 2369838 A GB2369838 A GB 2369838A GB 0029987 A GB0029987 A GB 0029987A GB 0029987 A GB0029987 A GB 0029987A GB 2369838 A GB2369838 A GB 2369838A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cleaning
- vessel
- drill cuttings
- water
- cleaning vessel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000004140 cleaning Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000005520 cutting process Methods 0.000 title claims abstract description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000007787 solid Substances 0.000 claims abstract description 20
- 239000007788 liquid Substances 0.000 claims abstract description 15
- 238000003860 storage Methods 0.000 claims abstract description 13
- 238000000926 separation method Methods 0.000 claims abstract description 11
- 239000011343 solid material Substances 0.000 claims abstract description 5
- 238000005201 scrubbing Methods 0.000 claims abstract description 4
- 239000012530 fluid Substances 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 12
- 239000000356 contaminant Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- 239000000470 constituent Substances 0.000 claims description 2
- 239000003921 oil Substances 0.000 description 21
- 239000011435 rock Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000009825 accumulation Methods 0.000 description 3
- 238000005553 drilling Methods 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 235000015076 Shorea robusta Nutrition 0.000 description 2
- 244000166071 Shorea robusta Species 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/06—Arrangements for treating drilling fluids outside the borehole
- E21B21/063—Arrangements for treating drilling fluids outside the borehole by separating components
- E21B21/065—Separating solids from drilling fluids
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
Apparatus for the cleaning of drill cuttings 1 comprises a vessel 8 in which the cleaning and primary solid/liquid separation takes place, a jet pump 6 or eductor for transferring the contaminated drill cuttings 1 from storage or transportation containers 2 to the cleaning vessel 8, a series of pumps 4, 20, conduits 5, 7, 11, 19 and a jetting ring 12 for circulating process water through the cleaning vessel 8, a venturi mixer 9 for mixing the water with the contaminated drill cuttings 1 in order to encourage a scrubbing action, and a hydrocylcone 21 for removing fine solids and contaminates from the process water. The cleaning vessel 8 incorporates a conveyor 14 for removing substantially solid material form the base of the vessel 8 and a weir 16, conduit 17 and storage vessel 18 for removing substantially oil based liquid from near the top of the vessel 8.
Description
METHOD AND APPARATUS FOR CLEANING DRILL CUTTINGS The process of drilling boreholes for the production of oil or gas from a subterranean reservoir generates waste material in the form of rock chippings, known as drill cuttings. During the drilling process such drill cuttings may be contaminated with hydrocarbons and chemicals which are considered to adversely affect the environment and therefore cannot be discharged freely into the surrounding area. The contaminated drill cuttings form a glutinous mass, particularly since the rock particles usually include hydroscopic shales which absorb some of the contaminating liquids to form a very soft and sticky outer layer. One method of safely disposing of the drill cuttings is to transport them to a treatment plant where the rock chippings are separated from the contaminants. Typically such treatment plants will also endeavour to recover as much of the hydrocarbons as possible for further use.
Many treatment plants remove the contaminants from the rock particles by the process of applying heat to the contaminated material in order to evaporate the contaminating liquids, which are then condensed and cleaned. Typical theoretical processing rates are 5.0 metric tonnes per hour of contaminated solids for each process line, although multiple lines may be operating at a single processing site to accommodate the amount of contaminated material being created where drilling is taking place over a wide geographic area, such as the Northern North Sea.
A typical sample of contaminated drill cuttings may comprise 50% solids, 30% water, 20% oil on a volumetric basis. It will be understood by those skilled in the art that a significant amount of thermal energy is required to process the material, and in
practice the high levels of liquid present with the solids may reduce the efficiency of the treatment plant to as little as 20% of the theoretical design capacity. Furthermore the resultant increase in thermal energy required has an adverse affect on the environment and the economics of the process.
In addition to the problem previously described, it is a peculiar property of the shale type of rock chippings that if the material is moved by pumping using centrifugal pumps it is observed to increase its absorption of oil, making subsequent removal more difficult.
Equipment for cleaning oil from sand particles, for example where a beach is contaminated by a marine crude oil spillage, is well known, but tests have shown that such equipment is not suitable for cleaning more porous rock particles such as the shales which often form drill cuttings. This is because the sand does not absorb the oil but is only coated with it, and therefore high velocity movement of the sand in water can scrub the oil from the surface of the particles. It is important when cleaning softer, more absorbent particles, that lower velocities are used to prevent breakage of the soft material and the resultant high volume of fine particles, and that dwell times within the system are increased to allow the more gentle flows to transfer the oil from the drill cuttings to the cleaning fluid.
An object of the present invention is to provide a means by which contaminated drill cuttings can be treated using water to remove most of the oil and water from the rock chippings prior to them entering the treatment plant.
In accordance with the first aspect of the present invention, a method and apparatus for the cleaning of drill cuttings comprises a vessel in which the cleaning and primary solid/liquid separation takes place, a means for transferring the contaminated drill cuttings from storage or transportation containers to the cleaning vessel, a means for circulating process water through the cleaning vessel, a means for mixing the water with the contaminated drill cuttings in order to encourage a scrubbing action, and a means for removing fine solids and contaminants from the process water. The cleaning vessel includes a means for removing substantially solid material from the base of the vessel and a means of removing substantially oil based liquid from near to the top of the vessel.
Preferably the means for transferring the contaminated drill cuttings from storage or transportation containers to the cleaning vessel is a jet pump or eductor.
Preferably the means for mixing the water with the contaminated drill cuttings in the cleaning vessel is based on the venturi principle.
Preferably the cleaning vessel is fitted with a baffle plate to assist with separation of solid particles from liquid.
Preferably the cleaning vessel is fitted with a conduit containing a plurality of openings for introducing additional fluid to aid the creation of hydrodynamic currents within the cleaning vessel to assist separation.
Preferably the process includes a means for separating oil/water mixtures into constituent parts.
Preferably the pumps used within the process have a means by which the rate of flow may be adjusted.
Preferably the process includes system of sensors and controls by which the process may be automated.
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which :
FIGURE 1 is a schematic diagram of the cleaning process.
FIGURE 2 is a diagram showing flow patterns within the cleaning vessel.
DESCRIPTION OF PROCESS
At the start of the cleaning operation the contaminated drill cuttings (1) are contained in a container (2). Process water is transferred from storage tank (3) by pump (4) and conduit (5) to the jet pump (6) which may be, by way of example, a Type 224 Water
Jet Sand and Mud Eductor from Schutte & Koerting of Bensalem, Pennsylvania in the
United States of America. The flow of water into the jet pump (6) causes the contaminated drill cuttings (1) to be entrained with the water and the water/contaminated drill cuttings mixture flows along conduit (7) into cleaning vessel (8). Inside the cleaning vessel (8) the water/contaminated drill cuttings mixture is
released into the centre of the venturi mixer (9) which may be, by way of example, a Type 268 Tank Mixing Eductor from Schutte & Koerting of Bensalem, Pennsylvania in the United States of America.. Figure 2 shows the flow patterns created within the cleaning vessel. The flow of water/contaminated drill cuttings into the venturi (9) causes a additional flow of liquid from within the cleaning vessel and results in thorough mixing and scrubbing of the contaminated drill cuttings in the venturi (9), transferring oil from the drill cuttings to the process water. The flow from the venturi (9) outlet is redirected by the deflector plate (10) to produce an annular flow around the outside of the venturi (9) which can re-enter the venturi (9) through the annular space around the water/contaminated drill cuttings inlet nozzle. Fluid may be introduced into the cleaning vessel (8) through a jetting ring (12) located within the cleaning vessel (8). Such fluid may be, by way of example, cold water, hot water, air, steam, or other appropriate fluid to assist separation. The jetting ring (12) may, by way of example, take the form of a conduit which may be a complete ring or an incomplete ring with the ends sealed. The jetting ring (12) contains a plurality of orifices through which the fluid can enter the cleaning vessel (8). Each orifice may be fitted with a means to prevent the fluid within the cleaning vessel (8) from entering the jetting ring (12). Fluid from the orifices in the jetting ring (12) creates an annular upward current around the downward current created by the deflector plate (10). The interface between the two flow patterns assists with the removal of oil and fine particles from the drill cuttings, which fall to the bottom of the cleaning vessel (8).
This flow interface may be enhanced by the use of adjustable flow diverter plates (not shown). A baffle plate (13), which may by way of example be a flat plate containing a plurality of holes, is fitted across the cleaning vessel (8) to retard the upward fluid flow and allow solid particles to be released from the flow and drop to the bottom of the cleaning vessel (8). The solids accumulation (31) at the bottom of the cleaning vessel (8) is removed from the cleaning vessel. This removal may be accomplished by an outlet conduit or by a conveyor means (14), which may be, by way of example, a screw conveyor. Such conveyor means (14) is sealed to prevent fluid escaping from the cleaning vessel (8), until such time as sufficient accumulation of solids has built up in the cleaning vessel (8) to permit removal of the solids without high levels of associated fluid. The solids accumulation is transferred by the conveyor means (14) into a container (15) for disposal or further processing, for example in a drill cuttings treatment plant. The fluid which passes through the baffle plate (13) in the cleaning vessel (8) is allowed to separate by differential density. The means of separation may be, by way of example, a fixed weir (16), a floating weir, or some other means. The least dense fluid, which is predominantly oil, flows over the weir (16) and out of the cleaning vessel (8) by means of a conduit (17) into a storage vessel (18). The more dense fluid, which is predominantly water contaminated with fine solid particles, is
drawn out of the cleaning vessel (8) by means of a conduit (19) and a pump (20). The flow through the conduit (19) may be adjusted, for example by means of a variable speed electric motor driving the pump (20), by means of a variable orifice at the end of conduit (19) within the cleaning vessel, or by other means, to balance the flow out of the cleaning vessel (8) with the flow into the cleaning vessel (8) from the jet pump (6). The flow of contaminated water from pump (20) enters a classification means which may be, by way of example, a hydrocyclone (21) which separates the solid particles from the liquid. The solid particles are deposited from the classification means (21) into a container (22) for disposal or further processing, for example in a drill cuttings treatment plant. The liquid is returned from the classification means (21) through a conduit (23) to the storage tank (3). The fluid stored in container (18)
which is predominantly oil, and the fluid in the storage tank (3) which is predominantly water, may be further refined by being passed through an oil/water separator (24). An example of an oil/water separator (24) is the Oilspin AV offered by Serck Baker of Gloucester in the United Kingdom. The predominantly oil fluid from container (18) is transferred by conduit (25) and pump (26) to the oil/water separator (24). The oil is separated into container (27). The clean water may be returned to the storage tank (3) through conduit (28) or discharged from the process, for example by a drain (29). The predominantly water fluid from storage tank (3) is transferred by pump (4) and conduit (30) to the oil/water separator (24). The oil is separated into container (27). The clean water may be returned to the storage tank (3) through conduit (28) or discharged from the process, for example by a drain (29). A plurality of valves are installed within the system described above to provide control of flow in the conduits.
The use of the term"process water"within the forgoing description means water circulated through the system as described and may include seawater, freshwater, waste water from another process, water which has been previously used to clean drill cuttings and may therefore itself contain small levels of contaminants, and any other fluid deemed suitable for the operation of the process.
Claims (14)
- CLAIMS 1. A method for the cleaning of drill cuttings comprising a vessel in which the cleaning and primary solid/liquid separation takes place, a means for transferring the contaminated drill cuttings from storage or transportation containers to the cleaning vessel, a means for circulating process water through the cleaning vessel, a means for mixing the water with the contaminated drill cuttings in order to encourage a scrubbing action, and a means for removing fine solids and contaminants from the process water.
- 2. A method as claimed in claim 1, in which the means for transferring the contaminated drill cuttings from storage or transportation containers to the cleaning vessel is a jet pump or eductor.
- 3. A method as ial 3. A method as claimed in claim 1 and 2, in which the process includes a means for separating oil/water mixtures into constituent parts.
- 4. A method as claimed in claim 1 to 3, in which the pumps used within the process have a means by which the rate of flow may be adjusted.
- 5. A method as claimed in claim 1 to 4, in which the process includes system of sensors and controls by which the process may be automated.
- 6. Apparatus for cleaning drill cuttings comprising a vessel in which the cleaning and primary solid/liquid separation takes place including a means for removingsubstantially solid material from the base of the vessel and a means of removing substantially oil based liquid from near to the top of the vessel.
- 7. Apparatus as claimed in claim 6, in which the means for mixing the water with the contaminated drill cuttings in the cleaning vessel is based on the venturi principle.
- 8. Apparatus as claimed in claim 6 and 7, in which the cleaning vessel is fitted with a baffle plate to assist with separation of solid particles from liquid.
- 9. Apparatus as claimed in claim 6 to 8, in which the cleaning vessel is fitted with a weir to assist with separation of oil from water.
- 10. Apparatus as claimed in claim 6 to 9, in which the cleaning vessel is fitted with a conduit containing a plurality of openings for introducing additional fluid to aid the creation of hydrodynamic currents within the cleaning vessel to assist separation.
- 11. A method substantially as described herein, with reference to the accompanying drawings
- 12. Apparatus substantially as described herein, with reference to and as shown in the accompanying drawings.
- 13. A method substantially as described herein, for the cleaning of substantially solid materials with a fluid.
- 14. Apparatus substantially as described herein, for the cleaning of substantially solid materials with a fluid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0029987A GB2369838A (en) | 2000-12-08 | 2000-12-08 | Method and apparatus for cleaning drill cuttings |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0029987A GB2369838A (en) | 2000-12-08 | 2000-12-08 | Method and apparatus for cleaning drill cuttings |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0029987D0 GB0029987D0 (en) | 2001-01-24 |
| GB2369838A true GB2369838A (en) | 2002-06-12 |
Family
ID=9904724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0029987A Withdrawn GB2369838A (en) | 2000-12-08 | 2000-12-08 | Method and apparatus for cleaning drill cuttings |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2369838A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012143851A2 (en) * | 2011-04-19 | 2012-10-26 | Fourie Stefan Adrian | Water treatment system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4451377A (en) * | 1982-02-05 | 1984-05-29 | Luxemburg S Roy | Process for cleaning an oil-contaminated brine containing particulate drill cutting solids |
| US4599117A (en) * | 1982-02-05 | 1986-07-08 | Luxemburg S Roy | Process for the decontamination of oil-contaminated particulate solids |
-
2000
- 2000-12-08 GB GB0029987A patent/GB2369838A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4451377A (en) * | 1982-02-05 | 1984-05-29 | Luxemburg S Roy | Process for cleaning an oil-contaminated brine containing particulate drill cutting solids |
| US4599117A (en) * | 1982-02-05 | 1986-07-08 | Luxemburg S Roy | Process for the decontamination of oil-contaminated particulate solids |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012143851A2 (en) * | 2011-04-19 | 2012-10-26 | Fourie Stefan Adrian | Water treatment system |
| WO2012143851A3 (en) * | 2011-04-19 | 2012-12-27 | Fourie Stefan Adrian | Water treatment system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0029987D0 (en) | 2001-01-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |