CA2319016A1 - Cleaning of drill cuttings and apparatus therefor - Google Patents
Cleaning of drill cuttings and apparatus therefor Download PDFInfo
- Publication number
- CA2319016A1 CA2319016A1 CA002319016A CA2319016A CA2319016A1 CA 2319016 A1 CA2319016 A1 CA 2319016A1 CA 002319016 A CA002319016 A CA 002319016A CA 2319016 A CA2319016 A CA 2319016A CA 2319016 A1 CA2319016 A1 CA 2319016A1
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- CA
- Canada
- Prior art keywords
- particulate solids
- drill cuttings
- accordance
- contaminants
- ngl
- 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.)
- Abandoned
Links
- 238000005520 cutting process Methods 0.000 title claims description 30
- 238000004140 cleaning Methods 0.000 title description 3
- 238000000034 method Methods 0.000 claims abstract description 32
- 239000007787 solid Substances 0.000 claims abstract description 30
- 239000000356 contaminant Substances 0.000 claims abstract description 23
- 230000008569 process Effects 0.000 claims abstract description 23
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 19
- 238000000605 extraction Methods 0.000 claims description 23
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 22
- 238000004519 manufacturing process Methods 0.000 claims description 20
- 239000007788 liquid Substances 0.000 claims description 14
- 239000007789 gas Substances 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 11
- 239000003345 natural gas Substances 0.000 claims description 10
- 239000012530 fluid Substances 0.000 description 12
- 239000011800 void material Substances 0.000 description 11
- 238000005553 drilling Methods 0.000 description 8
- 239000002904 solvent Substances 0.000 description 7
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 6
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 5
- 150000002430 hydrocarbons Chemical class 0.000 description 5
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 239000000470 constituent Substances 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- 239000001273 butane Substances 0.000 description 2
- RWRIWBAIICGTTQ-UHFFFAOYSA-N difluoromethane Chemical compound FCF RWRIWBAIICGTTQ-UHFFFAOYSA-N 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 238000003113 dilution method Methods 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 2
- 238000010587 phase diagram Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 125000005907 alkyl ester group Chemical group 0.000 description 1
- 125000005011 alkyl ether group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229960004424 carbon dioxide Drugs 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000000194 supercritical-fluid extraction Methods 0.000 description 1
- 239000010891 toxic waste Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- E21B21/066—Separating solids from drilling fluids with further treatment of the solids, e.g. for disposal
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)
- Extraction Or Liquid Replacement (AREA)
Abstract
The present invention comprises a process and apparatus for removing nonpolar organic contaminants including oil from particulate solids, wherein said solids are brought in contact with an extracting agent.
Description
,', , , , ". , , , , , , , , ' CLEANING OF DRILL CUTTINGS AND APPARATUS THEREOF
The present invention comprises a process and an apparatus for removing non-polar organic contaminants including oil from particulate solid wherein said solids s is brought in contact with an extracting agent. The use of natural gas as an ex-tracting agent is also described in the present invention.
Components from the drilling and well-operations represents 94% of total dis-charge of chemicals from the offshore oil industry in the Norwegian sector (Mil-jresok report, 1996, OLF) . Oil-based drilling fluids have traditionally been favoured over aqueous based systems because they are more cost-efficient. The present development in directional drilling techniques has further dictated the need for more efficient environmental friendly drilling fluids. Following the complete ban against the discharge of oil-based drill cuttings in the early 90's, a new generation ,s of synthetic drilling fluids emerged. These fluids were based on alkyl-ester or-ethers and poly-alfa-olefines. They were classified as «non toxic» and were per-mitted to be discarded overboard. These synthetic drilling-fluids offers the same drilling performance as oil-based drilling-fluids, but at a significantly higher cost.
Recent research indicates however that these synthetic fluids represent an envi-Zo ronmental hazard, and their use is expected to be restricted in the near future (Milja~sok report, 1996, OLF). It appears that the industry has no other alternative than using oil-based drilling fluids in the future. The drill cuttings will either have to be disposed on-shore or re-injected into the reservoir. Both alternatives are ex-tremely expensive. It appears however that re-injection is generally favoured by is both the legislators and the industry. According-to-the Norwegian Pollution Control Authority there are not yet any specific guidelines for the disposal of produced sand, and it is generally assumed that the current guidelines and legislation for disposal of «drill cuttings» might also apply for produced sand. The maximum re-sidual oil content for overboard disposal of drill cuttings is 1.0%. Sand or drill cut-so tings with higher oil contents is considered «toxic waste» and has to be either re-injected into the reservoir or brought on shore for processing.
The Norwegian patent application number 19953419 (PCT/N000060), Inge Brun Henriksen et al, describes a method for NGL extraction-techniques for de-oiling of o w . , .,~ "' ' produced water. The process does not include removal of organic contaminants from solids.
The use of supercritical extraction techniques to remove and recover oil from cut-s tings was first proposed in 1981 by C.P.Eppig et al in US-patent no.
4.434.028.
US 4.434.028 relates to a method and apparatus for removing oil and other or-ganic constituents from inorganic-rich mineral solids, particulate drill cuttings. The solids to be treated are transferred into pressure vessel means wherein they are contacted with an extracting agent which is normally a gas such as e.g.
dichloro-io difluoromethane, propan, carbondioxide, ethane and ethylene. The gas is under condition of pressure and temperature to provide the extracting in a fluidic solvent state for the constituents to be removed. The extracting containing the constituents is withdrawn from the pressure vessel and depressurized and forms a two-phase system. The two-phase system can be separated by distillation into a vapour phase containing the extracting and a liquid phase containing oil and organic con-stituents. The method described in US 4.434.028 is a very expensive extraction process comprising the use of pure gas components as an extracting agent fol-lowed by compression- and to-steps distillation procedures to fully recover the ex-tracting agent which is pure gas components. In order for the process to be eco-zo nomic feasible, full recovery of the extracting agent (99.7%) is required.
The proc-ess described in US 4.434.028 is based on using liquid gas (i.e.COz, Propane or Freon) to extract the oil and to fully recycle the gas (99.7%). The proposed proc-ess has apparently never been scaled up to an industrial plant .
25 US-A-4485079 discloses a process for remov+Rg-~onpolar organic contaminants in a three-step serial extraction process for separating residual heavy organic con-taminants from solids, where each step has the following main characteristics.
Step 1: Contacting the solids with a hydrocarbon fluid composed of 2 to 9 carbon atoms.
so Step 2. Contacting the solids from Step1 with a second hydrocarbon fluid that is capable of dissolving part of the heavy contaminants from the solids.
Step 3: Contacting the solids from Step 2 with a third hydrocarbon fluid composed of 2 to 9 hydrocarbon atoms to extract part of the residual hydrocarbon fluid from step 2.
'.,' ,' '..' '.,' ' This process is distinct from the present invention in that the extraction is con-ducted in three steps where different solvents are used at each step. It should be stressed that the present invention is a one step extraction process for removing nonpolar organic contaminants in which only one extracting agent (NGL) is added.
WO-A-9108375 concerns an extraction method and apparatus which uses organic solvent, i.e. toluene or stabilised gasoline. WO-A-9108375 requires regeneration of solvent and a dryer to remove residual solvent from the cleaned cuttings.
This is distinct from the present invention in that said invention uses pressurised natural ,o gas liquid which is volatile at ambient conditions and which is available from a pro-duction flow-line and requires no regeneration.
As the oilfields matures and the water-cut increases, more sand from the reservoir formation tends to follow the production stream in some oilfields. The sand settles ~5 in the separators and are periodically washed out and disposed by re-injection or brought ashore for disposal or processing. One object is therefore to provide an inventive and cost-effective process for cleaning of oily-drill cuttings and sand to allow overboard discard of the cuttings.
zo The present invention concerning a method of extracting oil from drill cuttings and sand offshore. The method is based upon using natural gas liquid (NGL) as a sol-vent to extract the oil from the soilds. The process has been successfully tested in lab-scale and the results shows less than 1.0% by weight of the maximum residual oil content for overboard disposal of drill cuttings. Further, the present invention z5 reduces the investment and operation costs to-a~-fraction of that which was pro-posed in US 4.434.028 since NGL is available from the production flw-lines at most oil and gas production facilities. Further, the present process is considerably distinct from other extraction processes in that it is carried out with no «solvent-recovery. One further object with the present invention is a significant saving in so chemical costs and utility requirement compared to re-injection or on-shore dis-posal of drill cuttings.
L
t ' ,' "~ , ., y,, , , ~,C!, The present invention comprises a process for removing nonpolar organic con-taminants including oil from particulate solids, wherein said solids are brought in contact with an extracting agent in which:
a) the particulate solids are conveyed into a pressure vessel to which an extracting s agent is added in the form of natural gas liquids (NGL), whereby the organic contaminants from the particulate solids are dissolved in the extraction agent to form a single phase solution;
b) whereafter said solution containing the extraction agent and nonpolar organic contaminants without any separation is added to a production flow;
,o c) and the clean particulate solids are discarded.
It is an object of the present invention that the extracting agent is a condensate collected from a production flow in the form of natural gas liquid. The cleaned par-ticulate solids contains less than 1 % by weight of organic nonpolar contaminants, ,s more preferably less than 0.5% by weight . The particulate solids comprise drill cuttings and sand in the present invention. An apparatus for removing nonpolar organic contaminants from drill cuttings is also described in this invention where said contaminated drill cuttings are contacted with an extractant to form a solution of said extractant and said contaminants, comprising:
20 - means for discarding clean drill cuttings after said contacting;
- means for conveying said solution to a production flow. A scope of the inven-tion is also the use of natural gas liquid as an extracting agent for removing or-ganic nonpolar contaminants including oil from particulate solids.
is The present process comprises the use of condeflsate (NGL) as a solvent to clean the drill cuttings and sand. Use of natural gas liquid according obtained from the production flow-line of oil and gas producing facilities is also object of the present invention.The NGL is conveyed from one of the production condensate flows at e.g. an oil drilling platform and used as a solvent and subsequently added back to so the production mainstream. A preliminary evaluation of the gas-condensate streams at several North Sea oilfields (Statfiord, Sleipner, Valhall, Ekofisk, Forties, Andrew) indicates that condensates (NGL) with the right thermodynamic proper-ty ties to act as a solvent are available in sufficient quantifies at these production fa-cilities. It is most likely that most oil and gas production facilities in the North Sea have access to such condensates.
The use of a NGL flow for extracting and subsequently adding the extract into the main production flow is a novel and cost-effective process. The process is carried out without «solvent-recovery» and with minimum utility requirement.
Figure 1 shows the experimental set-up for the extraction of drill cuttings with NGL.
NGL is conveyed from e.g. a NGL container (1) through a valve (2) and a pump (3), and further trough the pipe 4. The NGL is conveyed through a valve 5 and io further pumped to an extracting cell (6) in which the drill cuttings are cleaned. The flow (7) containing NGL and the organic contaminants may optionally be con-veyed to a production flow-line. The Figure 2 shows a phase diagram of the avail-able NGL, and figure 3 showes the residual oil versus void volumes of NGL.
The present invention comprises a process and an apparatus for removing non-polar organic contaminants including oil from particulate solid wherein said solids s is brought in contact with an extracting agent. The use of natural gas as an ex-tracting agent is also described in the present invention.
Components from the drilling and well-operations represents 94% of total dis-charge of chemicals from the offshore oil industry in the Norwegian sector (Mil-jresok report, 1996, OLF) . Oil-based drilling fluids have traditionally been favoured over aqueous based systems because they are more cost-efficient. The present development in directional drilling techniques has further dictated the need for more efficient environmental friendly drilling fluids. Following the complete ban against the discharge of oil-based drill cuttings in the early 90's, a new generation ,s of synthetic drilling fluids emerged. These fluids were based on alkyl-ester or-ethers and poly-alfa-olefines. They were classified as «non toxic» and were per-mitted to be discarded overboard. These synthetic drilling-fluids offers the same drilling performance as oil-based drilling-fluids, but at a significantly higher cost.
Recent research indicates however that these synthetic fluids represent an envi-Zo ronmental hazard, and their use is expected to be restricted in the near future (Milja~sok report, 1996, OLF). It appears that the industry has no other alternative than using oil-based drilling fluids in the future. The drill cuttings will either have to be disposed on-shore or re-injected into the reservoir. Both alternatives are ex-tremely expensive. It appears however that re-injection is generally favoured by is both the legislators and the industry. According-to-the Norwegian Pollution Control Authority there are not yet any specific guidelines for the disposal of produced sand, and it is generally assumed that the current guidelines and legislation for disposal of «drill cuttings» might also apply for produced sand. The maximum re-sidual oil content for overboard disposal of drill cuttings is 1.0%. Sand or drill cut-so tings with higher oil contents is considered «toxic waste» and has to be either re-injected into the reservoir or brought on shore for processing.
The Norwegian patent application number 19953419 (PCT/N000060), Inge Brun Henriksen et al, describes a method for NGL extraction-techniques for de-oiling of o w . , .,~ "' ' produced water. The process does not include removal of organic contaminants from solids.
The use of supercritical extraction techniques to remove and recover oil from cut-s tings was first proposed in 1981 by C.P.Eppig et al in US-patent no.
4.434.028.
US 4.434.028 relates to a method and apparatus for removing oil and other or-ganic constituents from inorganic-rich mineral solids, particulate drill cuttings. The solids to be treated are transferred into pressure vessel means wherein they are contacted with an extracting agent which is normally a gas such as e.g.
dichloro-io difluoromethane, propan, carbondioxide, ethane and ethylene. The gas is under condition of pressure and temperature to provide the extracting in a fluidic solvent state for the constituents to be removed. The extracting containing the constituents is withdrawn from the pressure vessel and depressurized and forms a two-phase system. The two-phase system can be separated by distillation into a vapour phase containing the extracting and a liquid phase containing oil and organic con-stituents. The method described in US 4.434.028 is a very expensive extraction process comprising the use of pure gas components as an extracting agent fol-lowed by compression- and to-steps distillation procedures to fully recover the ex-tracting agent which is pure gas components. In order for the process to be eco-zo nomic feasible, full recovery of the extracting agent (99.7%) is required.
The proc-ess described in US 4.434.028 is based on using liquid gas (i.e.COz, Propane or Freon) to extract the oil and to fully recycle the gas (99.7%). The proposed proc-ess has apparently never been scaled up to an industrial plant .
25 US-A-4485079 discloses a process for remov+Rg-~onpolar organic contaminants in a three-step serial extraction process for separating residual heavy organic con-taminants from solids, where each step has the following main characteristics.
Step 1: Contacting the solids with a hydrocarbon fluid composed of 2 to 9 carbon atoms.
so Step 2. Contacting the solids from Step1 with a second hydrocarbon fluid that is capable of dissolving part of the heavy contaminants from the solids.
Step 3: Contacting the solids from Step 2 with a third hydrocarbon fluid composed of 2 to 9 hydrocarbon atoms to extract part of the residual hydrocarbon fluid from step 2.
'.,' ,' '..' '.,' ' This process is distinct from the present invention in that the extraction is con-ducted in three steps where different solvents are used at each step. It should be stressed that the present invention is a one step extraction process for removing nonpolar organic contaminants in which only one extracting agent (NGL) is added.
WO-A-9108375 concerns an extraction method and apparatus which uses organic solvent, i.e. toluene or stabilised gasoline. WO-A-9108375 requires regeneration of solvent and a dryer to remove residual solvent from the cleaned cuttings.
This is distinct from the present invention in that said invention uses pressurised natural ,o gas liquid which is volatile at ambient conditions and which is available from a pro-duction flow-line and requires no regeneration.
As the oilfields matures and the water-cut increases, more sand from the reservoir formation tends to follow the production stream in some oilfields. The sand settles ~5 in the separators and are periodically washed out and disposed by re-injection or brought ashore for disposal or processing. One object is therefore to provide an inventive and cost-effective process for cleaning of oily-drill cuttings and sand to allow overboard discard of the cuttings.
zo The present invention concerning a method of extracting oil from drill cuttings and sand offshore. The method is based upon using natural gas liquid (NGL) as a sol-vent to extract the oil from the soilds. The process has been successfully tested in lab-scale and the results shows less than 1.0% by weight of the maximum residual oil content for overboard disposal of drill cuttings. Further, the present invention z5 reduces the investment and operation costs to-a~-fraction of that which was pro-posed in US 4.434.028 since NGL is available from the production flw-lines at most oil and gas production facilities. Further, the present process is considerably distinct from other extraction processes in that it is carried out with no «solvent-recovery. One further object with the present invention is a significant saving in so chemical costs and utility requirement compared to re-injection or on-shore dis-posal of drill cuttings.
L
t ' ,' "~ , ., y,, , , ~,C!, The present invention comprises a process for removing nonpolar organic con-taminants including oil from particulate solids, wherein said solids are brought in contact with an extracting agent in which:
a) the particulate solids are conveyed into a pressure vessel to which an extracting s agent is added in the form of natural gas liquids (NGL), whereby the organic contaminants from the particulate solids are dissolved in the extraction agent to form a single phase solution;
b) whereafter said solution containing the extraction agent and nonpolar organic contaminants without any separation is added to a production flow;
,o c) and the clean particulate solids are discarded.
It is an object of the present invention that the extracting agent is a condensate collected from a production flow in the form of natural gas liquid. The cleaned par-ticulate solids contains less than 1 % by weight of organic nonpolar contaminants, ,s more preferably less than 0.5% by weight . The particulate solids comprise drill cuttings and sand in the present invention. An apparatus for removing nonpolar organic contaminants from drill cuttings is also described in this invention where said contaminated drill cuttings are contacted with an extractant to form a solution of said extractant and said contaminants, comprising:
20 - means for discarding clean drill cuttings after said contacting;
- means for conveying said solution to a production flow. A scope of the inven-tion is also the use of natural gas liquid as an extracting agent for removing or-ganic nonpolar contaminants including oil from particulate solids.
is The present process comprises the use of condeflsate (NGL) as a solvent to clean the drill cuttings and sand. Use of natural gas liquid according obtained from the production flow-line of oil and gas producing facilities is also object of the present invention.The NGL is conveyed from one of the production condensate flows at e.g. an oil drilling platform and used as a solvent and subsequently added back to so the production mainstream. A preliminary evaluation of the gas-condensate streams at several North Sea oilfields (Statfiord, Sleipner, Valhall, Ekofisk, Forties, Andrew) indicates that condensates (NGL) with the right thermodynamic proper-ty ties to act as a solvent are available in sufficient quantifies at these production fa-cilities. It is most likely that most oil and gas production facilities in the North Sea have access to such condensates.
The use of a NGL flow for extracting and subsequently adding the extract into the main production flow is a novel and cost-effective process. The process is carried out without «solvent-recovery» and with minimum utility requirement.
Figure 1 shows the experimental set-up for the extraction of drill cuttings with NGL.
NGL is conveyed from e.g. a NGL container (1) through a valve (2) and a pump (3), and further trough the pipe 4. The NGL is conveyed through a valve 5 and io further pumped to an extracting cell (6) in which the drill cuttings are cleaned. The flow (7) containing NGL and the organic contaminants may optionally be con-veyed to a production flow-line. The Figure 2 shows a phase diagram of the avail-able NGL, and figure 3 showes the residual oil versus void volumes of NGL.
~ The NGL has to be in liquid state at the pressure and temperature of extraction.
~ The NGL has to be in gaseous state at atmospheric pressure at the extraction temperature.
It is apparent from the phase diagram of the available NGL (Figure 2) that at 60°C, s the minimum extraction pressure is aproximatly 20 bar.
The extraction cell was always first completely filled with the drill cuttings (about 630-660 g) and then completely flooded with NGL (about 600 ml) at a pressure of 30 bar, agitation was applied by turning the extraction cell up side down twice.
Table 3 shows the results. The "void volume = 694 ml" is defined as the volume of NGL which can be added to the extraction cell containing the drill cuttings plus the volume of the tube connecting the cell to the choke valve.
Table 2: Molar compositions of NGL
Methane 0.0336 Butane 0.1848 Ethane 0.1272 (pentane 0.1102 Propane 0.1984 Pentane 0.1620 (butane 0.0754 Hexane 0.1074 WO 99/40292 PCT/N099/OOb37 Table 3: Extraction of 623.7 g drill cuttings (34/10-D4H) with NGL at 30bar, 60°C
V(liquid gas)void moil) removed [wt [ml] volumescollected oil %]
[g] [wt %] Wet basis 694 1 0 0 7.20 932 1.3 4.9 10.9 6.46 1156 1.7 16.4 36.5 4.69 1268 1.8 21.3 47.4 3.92 1550 2.2 27.4 60.9 2.94 2060 3.0 33.3 74.1 1.97 2550 3.7 39.5 87.9 0.93 2920 4.2 41.4 92.1 0.61 3278 4.7 42.4 94.3 0.44 3914 5.6 43.2 96.1 0.30 4280 6.2 43.3 96.3 0.28 Figure 3 shows the residual oil content (related to the wet sample) on the drill cut-s tings versus the void volume of NGL injected. It is apparent from Figure 3 that the initial oil concentration of 7.2 wt % remains in the cell until it is flooded with the first void volume of NGL. Upon additional injection of NGL, a reduction of the oil content is evident. It is apparent that each time one void-volume is injected, the concentration is reduced by approximately 50%. The experimental data were con-~o sequently compared with the relationship expected from a pure dilution process.
The following genera! equation were used for the dilution-model:
C=Co*0.5~"-~~
~s wherein:
C°= Initial oil concentration C= Residual oil concentration n= number of void volumes injected "' "' , ~"~ ,' ~ '.,. ',~' Table 3: Extraction of 623.7 g drill cuttings (34/10-D4H) with NGL at 30bar, 60°C
V(liquid void moil) removed [wt gas) volumes collected oil %]
[ml] [g] [wt %] Wet basis 694 1 0 0 7.20 932 1.3 4.9 10.9 6.46 1156 1.7 16.4 36.5 4.69 1268 1.8 21.3 47.4 3.92 1550 2.2 27.4 60.9 2.94 2060 3.0 33.3 74.1 1.97 2550 3.7 39.5 87.9 0.93 2920 4.2 41.4 92.1 0.61 3278 4.7 42.4 94.3 0.44 3914 5.6 43.2 96.1 0.30 4280 6.2 43.3 96.3 0.28 Figure 3 shows the residual oil content (related to the wet sample) on the drill cut-s tings versus the void volume of NGL injected. It is apparent from Figure 3 that the initial oil concentration of 7.2 wt % remains in the cell until it is flooded with the first void volume of NGL. Upon additional injection of NGL, a reduction of the oil content is evident. It is apparent that each time one void-volume is injected, the concentration is reduced by approximately 50%. The experimental data were con-,o sequently compared with the relationship expected from a pure dilution process.
The following general equation were used for the dilution-model:
C=Co*0.5~"'~~ _ wherein:
C°= Initial oil concentration C= Residual oil concentration n= number of void volumes injected ,.. , ; , ,. , ; ; , c, ., ., The experimental data correspond very well with the graph for the dilution model as illustrated in Figure 3. It is apparent that the NGL-extraction of the oil from cut-tings obeys the rules for dilution. Which indicates that the oil is already completely dissolved in the NGL at the first void volume. It is therefor reasonable to assume s that the extraction process is fast and exhibits no significant mass-transfer restric-tions.
All drill cuttings which were tested, exhibited the same behaviour as presented in Figure 3 and the results are summarised in Table 4.
Table 4:Oil concentration (weight %) before and after extraction with NGL
Drill cuttings 34/10-D4H 34/10-G-2T2H 30/3-A9A
(Gullfaks) (Gullfaks) (Veslefrikk) Initial concentration7,2 9.0 18,6 Residual concentra-0.28 0.37 0.22 tion (wet basis) Residual concentra-0.26 0.34 0.20 tion (dry basis) w a Q
~ The NGL has to be in gaseous state at atmospheric pressure at the extraction temperature.
It is apparent from the phase diagram of the available NGL (Figure 2) that at 60°C, s the minimum extraction pressure is aproximatly 20 bar.
The extraction cell was always first completely filled with the drill cuttings (about 630-660 g) and then completely flooded with NGL (about 600 ml) at a pressure of 30 bar, agitation was applied by turning the extraction cell up side down twice.
Table 3 shows the results. The "void volume = 694 ml" is defined as the volume of NGL which can be added to the extraction cell containing the drill cuttings plus the volume of the tube connecting the cell to the choke valve.
Table 2: Molar compositions of NGL
Methane 0.0336 Butane 0.1848 Ethane 0.1272 (pentane 0.1102 Propane 0.1984 Pentane 0.1620 (butane 0.0754 Hexane 0.1074 WO 99/40292 PCT/N099/OOb37 Table 3: Extraction of 623.7 g drill cuttings (34/10-D4H) with NGL at 30bar, 60°C
V(liquid gas)void moil) removed [wt [ml] volumescollected oil %]
[g] [wt %] Wet basis 694 1 0 0 7.20 932 1.3 4.9 10.9 6.46 1156 1.7 16.4 36.5 4.69 1268 1.8 21.3 47.4 3.92 1550 2.2 27.4 60.9 2.94 2060 3.0 33.3 74.1 1.97 2550 3.7 39.5 87.9 0.93 2920 4.2 41.4 92.1 0.61 3278 4.7 42.4 94.3 0.44 3914 5.6 43.2 96.1 0.30 4280 6.2 43.3 96.3 0.28 Figure 3 shows the residual oil content (related to the wet sample) on the drill cut-s tings versus the void volume of NGL injected. It is apparent from Figure 3 that the initial oil concentration of 7.2 wt % remains in the cell until it is flooded with the first void volume of NGL. Upon additional injection of NGL, a reduction of the oil content is evident. It is apparent that each time one void-volume is injected, the concentration is reduced by approximately 50%. The experimental data were con-~o sequently compared with the relationship expected from a pure dilution process.
The following genera! equation were used for the dilution-model:
C=Co*0.5~"-~~
~s wherein:
C°= Initial oil concentration C= Residual oil concentration n= number of void volumes injected "' "' , ~"~ ,' ~ '.,. ',~' Table 3: Extraction of 623.7 g drill cuttings (34/10-D4H) with NGL at 30bar, 60°C
V(liquid void moil) removed [wt gas) volumes collected oil %]
[ml] [g] [wt %] Wet basis 694 1 0 0 7.20 932 1.3 4.9 10.9 6.46 1156 1.7 16.4 36.5 4.69 1268 1.8 21.3 47.4 3.92 1550 2.2 27.4 60.9 2.94 2060 3.0 33.3 74.1 1.97 2550 3.7 39.5 87.9 0.93 2920 4.2 41.4 92.1 0.61 3278 4.7 42.4 94.3 0.44 3914 5.6 43.2 96.1 0.30 4280 6.2 43.3 96.3 0.28 Figure 3 shows the residual oil content (related to the wet sample) on the drill cut-s tings versus the void volume of NGL injected. It is apparent from Figure 3 that the initial oil concentration of 7.2 wt % remains in the cell until it is flooded with the first void volume of NGL. Upon additional injection of NGL, a reduction of the oil content is evident. It is apparent that each time one void-volume is injected, the concentration is reduced by approximately 50%. The experimental data were con-,o sequently compared with the relationship expected from a pure dilution process.
The following general equation were used for the dilution-model:
C=Co*0.5~"'~~ _ wherein:
C°= Initial oil concentration C= Residual oil concentration n= number of void volumes injected ,.. , ; , ,. , ; ; , c, ., ., The experimental data correspond very well with the graph for the dilution model as illustrated in Figure 3. It is apparent that the NGL-extraction of the oil from cut-tings obeys the rules for dilution. Which indicates that the oil is already completely dissolved in the NGL at the first void volume. It is therefor reasonable to assume s that the extraction process is fast and exhibits no significant mass-transfer restric-tions.
All drill cuttings which were tested, exhibited the same behaviour as presented in Figure 3 and the results are summarised in Table 4.
Table 4:Oil concentration (weight %) before and after extraction with NGL
Drill cuttings 34/10-D4H 34/10-G-2T2H 30/3-A9A
(Gullfaks) (Gullfaks) (Veslefrikk) Initial concentration7,2 9.0 18,6 Residual concentra-0.28 0.37 0.22 tion (wet basis) Residual concentra-0.26 0.34 0.20 tion (dry basis) w a Q
Claims (10)
1. A process for removing nonpolar organic contaminants including oil from particulate solids, wherein said solids are brought in contact with an extracting agent characterised in that:
a) the particulate solids are conveyed into a pressure vessel to which an extracting agent is added in the form of natural gas liquids (NGL), whereby the organic contaminants from the particulate solids are dissolved in the extraction agent to form a single phase solution;
b) said solution containing the extraction agent and nonpolar organic contaminants may be conveyed to a production flow-line; or may not be quantitatively conveyed to a production flow-line;
c) and the clean particulate solids are discarded.
a) the particulate solids are conveyed into a pressure vessel to which an extracting agent is added in the form of natural gas liquids (NGL), whereby the organic contaminants from the particulate solids are dissolved in the extraction agent to form a single phase solution;
b) said solution containing the extraction agent and nonpolar organic contaminants may be conveyed to a production flow-line; or may not be quantitatively conveyed to a production flow-line;
c) and the clean particulate solids are discarded.
2. Process in accordance with claim 1, characterised in that the extraction agent is a condensate collected from a production flow-line in the form of natural gas liquid.
3. Process in accordance with claim 2, characterised in that said non-polar contaminants may not be quantitatively conveyed to a production flow-line.
4. Process in accordance with the claims 1-3, characterised in that the cleaned particulate solids contains less than 1% by weight of organic non-polar contaminants.
5. Process in accordance with the claims 1-4, characterised in that the cleaned particulate solids contains less than 0.5% by weight of organic non-polar contaminants.
6. Process in accordance with the claims 1 -5, characterised in that said particulate solids comprise drill cuttings.
7. Process in accordance with the claims 1 -6, characterised in that said particulate solids comprise sand.
8. Process in accordance with the claims 1 - 5, characterised in that said particulate solids comprise sand.
9. Apparatus for removing nonpolar organic contaminants from drill cuttings by contacting said contaminated drill cuttings (6) with an extractant (1) to form a solution of said extractant and said contaminants, characterised in that:
- means for discarding clean drill cuttings after said contacting;
- means for conveying said solution to a flow production line.
- means for discarding clean drill cuttings after said contacting;
- means for conveying said solution to a flow production line.
10. Use of natural gas liquid according to claim 9, where natural gas liquid is obtained from the production flow-line of oil and gas producing facilities.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US7354698P | 1998-02-03 | 1998-02-03 | |
| US60/073,546 | 1998-02-03 | ||
| PCT/NO1999/000037 WO1999040292A1 (en) | 1998-02-03 | 1999-02-03 | Cleaning of drill cuttings and apparatus therfor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2319016A1 true CA2319016A1 (en) | 1999-08-12 |
Family
ID=22114348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002319016A Abandoned CA2319016A1 (en) | 1998-02-03 | 1999-02-03 | Cleaning of drill cuttings and apparatus therefor |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1053384A1 (en) |
| AU (1) | AU2442799A (en) |
| CA (1) | CA2319016A1 (en) |
| WO (1) | WO1999040292A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050236015A1 (en) * | 2004-04-26 | 2005-10-27 | Halliburton Energy Services, Inc. | Drill cutting deoiling |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4434028A (en) * | 1981-04-17 | 1984-02-28 | Critical Fluid Systems, Inc. | Apparatus for removing organic contaminants from inorganic-rich mineral solids |
| US4885079A (en) * | 1986-09-12 | 1989-12-05 | The Standard Oil Company | Process for separating organic material from particulate solids |
| GB2239470B (en) * | 1989-11-28 | 1993-12-15 | Rig Technology Ltd | Cleaning of cuttings from drilling operations |
| CA2068997A1 (en) * | 1989-11-28 | 1991-05-29 | Marshall Graham Bailey | Cleaning of cuttings from drilling operations |
-
1999
- 1999-02-03 EP EP99903955A patent/EP1053384A1/en not_active Withdrawn
- 1999-02-03 AU AU24427/99A patent/AU2442799A/en not_active Abandoned
- 1999-02-03 CA CA002319016A patent/CA2319016A1/en not_active Abandoned
- 1999-02-03 WO PCT/NO1999/000037 patent/WO1999040292A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999040292A1 (en) | 1999-08-12 |
| AU2442799A (en) | 1999-08-23 |
| EP1053384A1 (en) | 2000-11-22 |
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