CA2121831C - Horizontal separator for treating under-balanced drilling fluid - Google Patents
Horizontal separator for treating under-balanced drilling fluidInfo
- Publication number
- CA2121831C CA2121831C CA002121831A CA2121831A CA2121831C CA 2121831 C CA2121831 C CA 2121831C CA 002121831 A CA002121831 A CA 002121831A CA 2121831 A CA2121831 A CA 2121831A CA 2121831 C CA2121831 C CA 2121831C
- Authority
- CA
- Canada
- Prior art keywords
- cuttings
- compartment
- weir
- separator
- 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.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/02—Settling tanks with single outlets for the separated liquid
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Cyclones (AREA)
Abstract
The separator comprises an elongated, cylindrical, horizontal pressure vessel. An involute feed inlet introduces the drilling fluid into the top of the vessel chamber at its first end. The feed inlet is designed to reduce the flow velocity of the incoming feed stream and introduce it horizontally toward the first end head of the vessel. A weir, slanted away from the first end head, extends upwardly from a point close to the head's base. The curved head, vessel side wall and slanted weir form an inlet compartment of hopper-like configuration,designed to funnel settling cuttings to a bottom outlet for removal with an auger pump. This design enables the cuttings to be removed while drilling progresses, without the build up of cuttings piles. The vessel also has a second weir at about its midpoint, for trapping fine solids in a second compartment. Riser outlets are provided in the second compartment for water removal and in the third compartment for oil removal. Gas is removed through an overhead outlet. A process is practised whereby pressurized drilling fluid returning from a well undergoing drilling is introduced into a closed pressurized separator wherein the liquid, gas and coarse cuttings are separated, the cuttings are collected and removed from the separator as a separate stream while drilling fluid continues to enter the separator, and the liquid and gas are also separately removed from the separator.
Description
FIELD OF THE INVENTION 1 2 1 8 3 ~
2 This invention relates to a separator designed to separate the
3 colllpo~ lts of drilling fluid returning from a well u"de,yoi,~y under-balanced drilling.
4 The invention further relates to a process of separating the co",~,or,~ of returning drilling fluid, practised under pressurized conditions.
7 Wells have long been drilled using drilling mud as the circulating medium.8 The mud performs two functions: it provides a column of heavy fluid that exerts 9 hydrostatic pressure at the bottom of the wellbore, to prevent entry into the wellbore of pressurized hydrocarbons present in the formation being drilled; and it serves to ~1 carry solid cuttings up and out of the wellbore.
12 When drilling mud is used, there is a likelihood that it will penetrate out 13 into a porous and permeable, hydrocarbon-containing reservoir when the reservoir is 14 being opened up or drilled through. When this occurs, the productivity of the well can be adversely affected. The mud that has p~ L~d radially into the formation acts 16 to impede the flow of hydrocarbons into the wellbore.
17 Under-balanced drilling was recently developed as a technique for 18 opening up the pay zone of the reservoir. Typically, the well is co"l~ d with casing 19 to the top of the pay zone. Then drilling is initiated into the pay zone using a relatively light circulating fluid, such as water or diesel fuel. The fluid is selected so that the 2 ~k 2t2?83t hydrostatic head created by it is less than the expected reservoir pressure. Therefore, 2 the drilling fluid will not invade the reservoir as the drilling string penetrates through it.
3 However, when this is done there is a likelihood that pressurized 4 hydlucaruons (oil or natural gas) present in the reservoir will be produced into the
7 Wells have long been drilled using drilling mud as the circulating medium.8 The mud performs two functions: it provides a column of heavy fluid that exerts 9 hydrostatic pressure at the bottom of the wellbore, to prevent entry into the wellbore of pressurized hydrocarbons present in the formation being drilled; and it serves to ~1 carry solid cuttings up and out of the wellbore.
12 When drilling mud is used, there is a likelihood that it will penetrate out 13 into a porous and permeable, hydrocarbon-containing reservoir when the reservoir is 14 being opened up or drilled through. When this occurs, the productivity of the well can be adversely affected. The mud that has p~ L~d radially into the formation acts 16 to impede the flow of hydrocarbons into the wellbore.
17 Under-balanced drilling was recently developed as a technique for 18 opening up the pay zone of the reservoir. Typically, the well is co"l~ d with casing 19 to the top of the pay zone. Then drilling is initiated into the pay zone using a relatively light circulating fluid, such as water or diesel fuel. The fluid is selected so that the 2 ~k 2t2?83t hydrostatic head created by it is less than the expected reservoir pressure. Therefore, 2 the drilling fluid will not invade the reservoir as the drilling string penetrates through it.
3 However, when this is done there is a likelihood that pressurized 4 hydlucaruons (oil or natural gas) present in the reservoir will be produced into the
5 wellbore. Thus the circulated fluid returning out of the wellbore will often comprise oil,
6 water, gas and suspended solids. In addition, this stream will be under pressure and
7 will have to be handled in a "closed" system - that is, in one or more pressure vessels
8 that are adapted to contain the components of the stream while they are separated
9 and recovered as discrete and separate streams.
û By way of contrast, a rig operating with drilling mud nommally has an 11 "open" tank system for treating a returning mud stream. More particularly, the mixture 12 of mud containing suspended solid cuttings passes through a vibrating screen 13 assembly (known as a "shale shaker") to separate out the bulk of the coarse bit 14 cuttings, which drop from the shaker onto the ground or into a pit. The mud then 1~ enters one or more rectangular, open-topped "mud tanks". The mud slowly moves 16 through the mud tank and most of the fine solids which remain suspended after 17 screening by the shale shaker settle out. Often the mud tank has one or more 18 transverse weirs or baflles, which divide the tank chamber into co,,,pd,l,,,t:l,la. The 19 weir functions to trap settling fine solids and thick mud, allowing "cleaned" mud to 20 advance. The cleaned mud then normally is recycled to the wellbore.
21 From time to time, the rig crew stop the mud flow, drain the tanks into a 22 pit and flush out settled solids using high pressure water jets or hoses.
,, .
2~21831 It is clear therefore that in conventional mud handling systems it is 2 known:
3 to provide retention time in the tanks to enable the fine solids to 4 settle out; and to use weirs in the path of the flow, to trap solids and heavily 6 co"Ld",ir,aLed mud, while cleaner mud passes over the weir and 7 moves toward the tank outlet.
8 These known concepts are i,,cor,uoldLed as part of the present invention in its 9 apparatus aspect.
SUMMARY OF THE INVENTION
11 The present invention was developed in connection with three prototypes 12 tested in sequence. In the course of building and testing the prototypes, applicants 13 e:,ldbli~l1ed the needs and means that came to be embodied in the third preferred 4 prototype.
Applicants' first prototype involved using a conventional vessel known as 16 a frac flow back tank. This was a vertical, cylindrical pressure vessel having a limited 17 volume capacity (100 barrels) and col"p,isil~y~
18 a bottom outlet for solids removal;
19 an overhead outlet for gas removal;
outlets at different elevations for separate water and oil removal;
. ,~;
2~21831 a sparger ring close to the bottom of the vessel chamber so that 2 water could be injected to fluidize and help remove solids out the 3 bottom outlet; and 4 a feed inlet structure having a T configuration, with its outlet being downwardly directed.
6 On using this vessel it was noted:
7 that the volume of the tank was relatively small and the volume of 8 cuttings large. This resulted in having to interrupt drilling 9 periodically to clean the solids from the tank by hooking up a vacuum truck to the bottom outlet to suction out the solids;
11 that the downwardly directed feed inlet was causing the gassy 12 incoming feed stream to jet down into the liquid and settling 13 solids, thereby stirring them up; and 14 thattheretentiontimewasir~ qu~t~ whichresultedintheliquid product(s) being c~ dl"i.,~l~d with solids.
16 At this point, the second prototype vessel was designed, built and tested.
17 It involved:
18 A hori~ontal, elongated, cylindrical pressure vessel having 550 19 barrels capacity;
2~21831 An inlet structure that was a tubular involute having its outlet 2 directed horizontally toward the curved head or end wall of the 3 vessel. The inlet structure was located at about the longitudinal 4 midpoint of the upper section of the vessel chamber. The inlet structure functioned to slow the flow velocity of the incoming feed 6 stream and to introduce it horizontally into the chamber;
7 A transverse weir extended across the chamber immediately 8 do.. n~ a", of the inlet structure dividing the chamber into 9 upstream and downstream compartments. The upstream compartment had sufficient volume to contain all of the coarse 11 solids which the well was expected to produce;
12 The length of the du~ ar~ compartment was sufficient to 13 provide enough retention time to allow the fines (clay and the like) 14 to settle out to an ~rcert~hl~ extent;
The outlet of the involute inlet structure was spaced above the 16 weir s rim so that gas could break out and not be entrained in the 17 accumulated liquid;
18 Oil and water outlet risers were provided .lu.. ~ a", of the weir 19 an overhead gas outlet was provided and solids outlets were provided in the base of the upstream and downstream 21 compartments.
, ~
21 21 83l This prototype worked well when tested in terms of providing non-2 interrupted service. However, it was characterized by one major defect. At the end of 3 the test on a well, it was necessary to open the vessel, purge it with nitrogen and send 4 workers into the gas-laced chamber to shovel the cuttings and silt to the bottom 5 outlets. A vacuum truck was used to suction out the solids. It took two men eight 6 hours to clean out the tank. The work was dangerous and the cost was high. It was 7 now clear that a system, having the capability to remove solids during drilling, was 8 needed.
9 This led to the design of the third prototype, which involved the desirable
û By way of contrast, a rig operating with drilling mud nommally has an 11 "open" tank system for treating a returning mud stream. More particularly, the mixture 12 of mud containing suspended solid cuttings passes through a vibrating screen 13 assembly (known as a "shale shaker") to separate out the bulk of the coarse bit 14 cuttings, which drop from the shaker onto the ground or into a pit. The mud then 1~ enters one or more rectangular, open-topped "mud tanks". The mud slowly moves 16 through the mud tank and most of the fine solids which remain suspended after 17 screening by the shale shaker settle out. Often the mud tank has one or more 18 transverse weirs or baflles, which divide the tank chamber into co,,,pd,l,,,t:l,la. The 19 weir functions to trap settling fine solids and thick mud, allowing "cleaned" mud to 20 advance. The cleaned mud then normally is recycled to the wellbore.
21 From time to time, the rig crew stop the mud flow, drain the tanks into a 22 pit and flush out settled solids using high pressure water jets or hoses.
,, .
2~21831 It is clear therefore that in conventional mud handling systems it is 2 known:
3 to provide retention time in the tanks to enable the fine solids to 4 settle out; and to use weirs in the path of the flow, to trap solids and heavily 6 co"Ld",ir,aLed mud, while cleaner mud passes over the weir and 7 moves toward the tank outlet.
8 These known concepts are i,,cor,uoldLed as part of the present invention in its 9 apparatus aspect.
SUMMARY OF THE INVENTION
11 The present invention was developed in connection with three prototypes 12 tested in sequence. In the course of building and testing the prototypes, applicants 13 e:,ldbli~l1ed the needs and means that came to be embodied in the third preferred 4 prototype.
Applicants' first prototype involved using a conventional vessel known as 16 a frac flow back tank. This was a vertical, cylindrical pressure vessel having a limited 17 volume capacity (100 barrels) and col"p,isil~y~
18 a bottom outlet for solids removal;
19 an overhead outlet for gas removal;
outlets at different elevations for separate water and oil removal;
. ,~;
2~21831 a sparger ring close to the bottom of the vessel chamber so that 2 water could be injected to fluidize and help remove solids out the 3 bottom outlet; and 4 a feed inlet structure having a T configuration, with its outlet being downwardly directed.
6 On using this vessel it was noted:
7 that the volume of the tank was relatively small and the volume of 8 cuttings large. This resulted in having to interrupt drilling 9 periodically to clean the solids from the tank by hooking up a vacuum truck to the bottom outlet to suction out the solids;
11 that the downwardly directed feed inlet was causing the gassy 12 incoming feed stream to jet down into the liquid and settling 13 solids, thereby stirring them up; and 14 thattheretentiontimewasir~ qu~t~ whichresultedintheliquid product(s) being c~ dl"i.,~l~d with solids.
16 At this point, the second prototype vessel was designed, built and tested.
17 It involved:
18 A hori~ontal, elongated, cylindrical pressure vessel having 550 19 barrels capacity;
2~21831 An inlet structure that was a tubular involute having its outlet 2 directed horizontally toward the curved head or end wall of the 3 vessel. The inlet structure was located at about the longitudinal 4 midpoint of the upper section of the vessel chamber. The inlet structure functioned to slow the flow velocity of the incoming feed 6 stream and to introduce it horizontally into the chamber;
7 A transverse weir extended across the chamber immediately 8 do.. n~ a", of the inlet structure dividing the chamber into 9 upstream and downstream compartments. The upstream compartment had sufficient volume to contain all of the coarse 11 solids which the well was expected to produce;
12 The length of the du~ ar~ compartment was sufficient to 13 provide enough retention time to allow the fines (clay and the like) 14 to settle out to an ~rcert~hl~ extent;
The outlet of the involute inlet structure was spaced above the 16 weir s rim so that gas could break out and not be entrained in the 17 accumulated liquid;
18 Oil and water outlet risers were provided .lu.. ~ a", of the weir 19 an overhead gas outlet was provided and solids outlets were provided in the base of the upstream and downstream 21 compartments.
, ~
21 21 83l This prototype worked well when tested in terms of providing non-2 interrupted service. However, it was characterized by one major defect. At the end of 3 the test on a well, it was necessary to open the vessel, purge it with nitrogen and send 4 workers into the gas-laced chamber to shovel the cuttings and silt to the bottom 5 outlets. A vacuum truck was used to suction out the solids. It took two men eight 6 hours to clean out the tank. The work was dangerous and the cost was high. It was 7 now clear that a system, having the capability to remove solids during drilling, was 8 needed.
9 This led to the design of the third prototype, which involved the desirable
10 features of the second prototype, but further il~collJuldl~d.
11 Forming the upstream compartment with a first weir which had its
12 base close to the vessel head (about 30 inches from it) and which
13 preferably slanted upwardly and away from the head, so that the
14 weir, curved head and vessel curved side wall in effect formed a hopper for funnelling settling solids to a solids outlet formed in the 16 vessel side wall at the foot of the compartment;
17 Providing a solids auger pump connected with the solids outlet of 18 the upstream compartment for removing solids while flow through 19 the vessel continued;
Positioning the involute feed inlet structure over the upstream 21 compartment, to direct the feed stream generally l1o, i~O~ lly and 22 toward the adjacent head;
....
~ . .
2~2183~
Providing water sparger inlets in the compartment to fluidi~e the 2 solids if required;
3 Providing a second weir at about the longitudinal midpoint of the 4 vessel chamber for trapping settling fines and defining i"~""e.lial~ and '~.. l~llt~dlll CC""~drt"~e~lts, 6 Providing a solids outlet in the base of the i"l~""edid~
7 ~o",lJart",e"l as well as a tubular riser having an elevated outlet 8 for removing water;
9 Providing an oil outlet from the du~ al~ co"",art",t:"l, said oil outlet culllplisillg a tubular riser having an elevated outlet for 11 removing oil; and 12 Providing manways leading into each compartment.
13 When tested it was found that the coarse solid bit cuttings could 14 satisfactorily be removed from the upstream compartment through its bottom outlet
17 Providing a solids auger pump connected with the solids outlet of 18 the upstream compartment for removing solids while flow through 19 the vessel continued;
Positioning the involute feed inlet structure over the upstream 21 compartment, to direct the feed stream generally l1o, i~O~ lly and 22 toward the adjacent head;
....
~ . .
2~2183~
Providing water sparger inlets in the compartment to fluidi~e the 2 solids if required;
3 Providing a second weir at about the longitudinal midpoint of the 4 vessel chamber for trapping settling fines and defining i"~""e.lial~ and '~.. l~llt~dlll CC""~drt"~e~lts, 6 Providing a solids outlet in the base of the i"l~""edid~
7 ~o",lJart",e"l as well as a tubular riser having an elevated outlet 8 for removing water;
9 Providing an oil outlet from the du~ al~ co"",art",t:"l, said oil outlet culllplisillg a tubular riser having an elevated outlet for 11 removing oil; and 12 Providing manways leading into each compartment.
13 When tested it was found that the coarse solid bit cuttings could 14 satisfactorily be removed from the upstream compartment through its bottom outlet
15 using the auger pump without interrupting drilling. Upon c~lllpltllioll of drilling
16 inspection showed that the upstream compartment was essentially free of solids. Silt
17 orfinesaccumulatedintheillle,l"e.iidlt:col"~.arl",~"lcouldbeflushedoutthroughthe
18 bottom outlet of the illlt:lllledidlt: compartment using a pressure hose inserted through
19 the opened manway. Thus the need for men to enter the tank and the need for a
20 vacuum suction truck were eliminated. Cleaning out the tank now involved two men
21 working for about 2 hours.
. 8 Broadly stated, the invention in an apparatus aspect comprises a closed 2 separator for sepal aLil ,g the components of under-balanced drilling fluid returning from 3 a well to produce separate streams of solid cuttings, gas, oil and water, when present 4 in the fluid, cu",,o~isi"g an elongated, horizontal, cylindrical pressure vessel having a 5 side wall and curved heads at its ends which together form a closed internal chamber, 6 said vessel having upstream and downstream ends; inlet means for introducing the 7 fluid through an aperture into the upper portion of the vessel chamber at its upstream 8 end; cuttings outlet means, positioned at the bottom of the chamber at its upstream 9 end, for removal of solid cuttings; a first weir extending upwardly from the bottom and 10 transversely of the chamber, said first weir being slanted away from the upstream end 11 head and being sealed to the vessel sidewall, said first weir having its top rim spaced 12 below the inlet end head on the du,~ tla~ " side of the cuttings outlet means; the first 13 weir, side wall and upstream end head combining to form a first compartment of 14 downwardlydiminishingcross-sectionalarea,saidcu,l"~all",e"~beingshapedtofunnel 15 settling cuttings down to the cuttings outlet means; the first compartment being 16 operative to receive the fluid being introduced by the inlet means; means, connected 17 with the cuttings outlet means, for ~ dla~;.lg solid cuttings therethrough; gas outlet 18 means for removing gas from the upper end of the chamber; water outlet means, 19 du..rl~ alll of the first weir, having an aperture for removing water that has settled 20 to the bottom end of the chamber and oil outlet means, downstream of the first weir, 21 having an aperture for removing oil.
.
Broadly stated, the invention in a method aspect comprises separating 2 the coll,po~ of drilling fluid returning from a well ulld~ly~ g under-balanced 3 drilling, said fluid being pressurized and co~ isi~g coarse cuttings, particulate fine 4 solids,atleastoneliquidcGl,,~ullell~andgaslcomprisingprovidingaclosed~horizontal 5 pressure vessel forming a chamber having upstream and du. ~ ar~ ends, said 6 vessel having wall means forming an internal upstanding compartment in the chamber 7 at its upstream end, said compartment having a du... I~. dly diminishing cross-section 8 area, inlet means for introducing the drilling fluid into the Cul l lpdl Ll l lt~ at its upper end, 9 cuttings outlet means at the base of the cu,,,pa,Llllell~ gas outlet means and liquid 1û outlet means for separately removing cuttings, liquid components and gas from the 1 1 vessel, said cuttings outlet means being connected with means for v. ;;l ldl ..~ cuttings 12 from the compartment, said wall means partly c~ll",ri~ g a weir so that liquid may 13 overflow from the compartment into the downstream end of the chamber; introducing 14 the drilling fluid into the compartment so that the cuttings settle and concentrate 15 I ' ... ,.. - dly while the liquid overflows the weir and moves into the du... I~ ltldlll end of 16 the chamber; withdrawing the col-ce"lldL~d cuttings from the vessel through the 17 cuttings outlet means using the ~v;;lldld~ means; settling fine solids from the 18 overflowed liquid and separately removing each liquid culllponulll from the vessel.
~ 10 In the broadest form of the invention, a novel method has evolved for 2 separatingtheco",yu"e"l~ofpressurizeddrillingfluidreturningfromawell~"de,yui,lg 3 drilling, said fluid cu",p(isi"g coarse cuttings, liquid and gas. The method cu"",li:,es.
4 introducing the pressurized drilling fluid into a closed pressurized separator means cunne~d with the well;
6 separating the cuttings, liquid and gas in the separator means;
7 collecting the separated cuttings in the separator means;
8 removing the collected cuttings from the separator means while 9 pressurized drilling fluid continues to enter the separator means 1û so that drilling is not interrupted; and 11 separately removing each of the gas and liquid from the separator 12 means.
14 Figure 1 is a side view showing the separator; and Figure 2 is a side view in section showing the separator and its internals.
~ 2121831 DESCRIPTION OF THE PRE~t~REJ EMBODIMENT
2 The separator A comprises an elongated, cylindrical pressure vessel 1 3 having a side wall 2 and curved heads 3,4 at its inlet (upstream) and outlet 4 (downstream) ends. The vessel 1 forms an internal chamber 5.
A feed inlet 6 of increasing cross-section and involute form extends into 6 the upper end of the vessel chamber 5 at its inlet end. The feed inlet 6 has an 7 aperture or outlet 7 opening toward the head 3 along a generally horizontal plane. The 8 feed inlet 6 is therefore operative to reduce the flow velocity of the feed stream as it 9 enters the chamber 5 and to direct it along a horizontal path toward the end head 3.
This arrangement is designed to minimize turbulence.
11 An internal first weir 8 extends upwardly from the bottom of the vessel 12 side wall 2. Its rim 9 is positioned close to but below the outlet 7 of the feed inlet 6.
13 The base 10 of the first weir 8 is close to but spaced from the head 3 (about 30 14 inches). The weir 8 is slanted away from the head 3 in a downstream direction, at about 45.
16 The slanted weir 8, vessel side wall 2 and curved head 3 combine to 17 form an inlet compartment 12 of dula.dly ,ii",i"i~ ,g cross-sectional area. In 18 operation, the weir 8, wall 2 and head 3 operate like a hopper to funnel settling 19 cuttings down to the foot of the compartment 12.
The involute feed inlet 6 is positioned over the inlet compartment 12.
The vessel side wall 2 forms a bottom outlet means 13 at the base of the 2 inlet COIllpd~ l 12 between the weir 8 and head 3. A solids auger pump 14 is 3 cul~lle~ d with the outlet means 13, for ~v;;I,d~ .,g cuttings from the inlet 4 compartment 12.
Perforated sparging lines 15 are positioned in the inlet co" ,~.arl",~ ~l 12 6 for injecting water as required to fluidize settled cuttings and assist in moving them 7 to the bottom outlet means 13.
8 A second weir 16 extends upwardly from the bottom of the vessel side 9 wall 2 at about the longitudinal midpoint of the chamber 5. The rim 17 of the second 10 weir 16 is positioned at a lower elevation than the rim 9 of the first weir 8. The two 11 weirs 8 16 and vessel side wall 2 combine to form an i"l~,l"edi~l~ co",uall",el,l 18.
12 A riser 19 extends upwardly into the intermediate cc,ll,palll"el,l 18 and provides an 13 outlet 20 for removal of water. The outlet 20 is positioned below the rim 17. A
14 manway 11 provides access to the i"le""edidLe compartment 18. Capped drains 22 1~ are provided in the bottom of the vessel side wall 2 for removal of flush water and 16 solids when cleaning the il,lt:""e.lial~ compartment 18.
17 A third compartment 23 is defined by the weir 16 side wall 2 and outlet 18 end head 4. A riser 24 extends upwardly into the third compartment 13 and provides 19 an outlet 25 for removal of oil. The outlet 25 is positioned beneath the rim 17. A
manway 26 provides access into the c~" ,parLI l ,~"~ 23. Capped drains 27 are provided 21 in the bottom of the vessel side wall 2, for removal of oil and flush water when cleaning
. 8 Broadly stated, the invention in an apparatus aspect comprises a closed 2 separator for sepal aLil ,g the components of under-balanced drilling fluid returning from 3 a well to produce separate streams of solid cuttings, gas, oil and water, when present 4 in the fluid, cu",,o~isi"g an elongated, horizontal, cylindrical pressure vessel having a 5 side wall and curved heads at its ends which together form a closed internal chamber, 6 said vessel having upstream and downstream ends; inlet means for introducing the 7 fluid through an aperture into the upper portion of the vessel chamber at its upstream 8 end; cuttings outlet means, positioned at the bottom of the chamber at its upstream 9 end, for removal of solid cuttings; a first weir extending upwardly from the bottom and 10 transversely of the chamber, said first weir being slanted away from the upstream end 11 head and being sealed to the vessel sidewall, said first weir having its top rim spaced 12 below the inlet end head on the du,~ tla~ " side of the cuttings outlet means; the first 13 weir, side wall and upstream end head combining to form a first compartment of 14 downwardlydiminishingcross-sectionalarea,saidcu,l"~all",e"~beingshapedtofunnel 15 settling cuttings down to the cuttings outlet means; the first compartment being 16 operative to receive the fluid being introduced by the inlet means; means, connected 17 with the cuttings outlet means, for ~ dla~;.lg solid cuttings therethrough; gas outlet 18 means for removing gas from the upper end of the chamber; water outlet means, 19 du..rl~ alll of the first weir, having an aperture for removing water that has settled 20 to the bottom end of the chamber and oil outlet means, downstream of the first weir, 21 having an aperture for removing oil.
.
Broadly stated, the invention in a method aspect comprises separating 2 the coll,po~ of drilling fluid returning from a well ulld~ly~ g under-balanced 3 drilling, said fluid being pressurized and co~ isi~g coarse cuttings, particulate fine 4 solids,atleastoneliquidcGl,,~ullell~andgaslcomprisingprovidingaclosed~horizontal 5 pressure vessel forming a chamber having upstream and du. ~ ar~ ends, said 6 vessel having wall means forming an internal upstanding compartment in the chamber 7 at its upstream end, said compartment having a du... I~. dly diminishing cross-section 8 area, inlet means for introducing the drilling fluid into the Cul l lpdl Ll l lt~ at its upper end, 9 cuttings outlet means at the base of the cu,,,pa,Llllell~ gas outlet means and liquid 1û outlet means for separately removing cuttings, liquid components and gas from the 1 1 vessel, said cuttings outlet means being connected with means for v. ;;l ldl ..~ cuttings 12 from the compartment, said wall means partly c~ll",ri~ g a weir so that liquid may 13 overflow from the compartment into the downstream end of the chamber; introducing 14 the drilling fluid into the compartment so that the cuttings settle and concentrate 15 I ' ... ,.. - dly while the liquid overflows the weir and moves into the du... I~ ltldlll end of 16 the chamber; withdrawing the col-ce"lldL~d cuttings from the vessel through the 17 cuttings outlet means using the ~v;;lldld~ means; settling fine solids from the 18 overflowed liquid and separately removing each liquid culllponulll from the vessel.
~ 10 In the broadest form of the invention, a novel method has evolved for 2 separatingtheco",yu"e"l~ofpressurizeddrillingfluidreturningfromawell~"de,yui,lg 3 drilling, said fluid cu",p(isi"g coarse cuttings, liquid and gas. The method cu"",li:,es.
4 introducing the pressurized drilling fluid into a closed pressurized separator means cunne~d with the well;
6 separating the cuttings, liquid and gas in the separator means;
7 collecting the separated cuttings in the separator means;
8 removing the collected cuttings from the separator means while 9 pressurized drilling fluid continues to enter the separator means 1û so that drilling is not interrupted; and 11 separately removing each of the gas and liquid from the separator 12 means.
14 Figure 1 is a side view showing the separator; and Figure 2 is a side view in section showing the separator and its internals.
~ 2121831 DESCRIPTION OF THE PRE~t~REJ EMBODIMENT
2 The separator A comprises an elongated, cylindrical pressure vessel 1 3 having a side wall 2 and curved heads 3,4 at its inlet (upstream) and outlet 4 (downstream) ends. The vessel 1 forms an internal chamber 5.
A feed inlet 6 of increasing cross-section and involute form extends into 6 the upper end of the vessel chamber 5 at its inlet end. The feed inlet 6 has an 7 aperture or outlet 7 opening toward the head 3 along a generally horizontal plane. The 8 feed inlet 6 is therefore operative to reduce the flow velocity of the feed stream as it 9 enters the chamber 5 and to direct it along a horizontal path toward the end head 3.
This arrangement is designed to minimize turbulence.
11 An internal first weir 8 extends upwardly from the bottom of the vessel 12 side wall 2. Its rim 9 is positioned close to but below the outlet 7 of the feed inlet 6.
13 The base 10 of the first weir 8 is close to but spaced from the head 3 (about 30 14 inches). The weir 8 is slanted away from the head 3 in a downstream direction, at about 45.
16 The slanted weir 8, vessel side wall 2 and curved head 3 combine to 17 form an inlet compartment 12 of dula.dly ,ii",i"i~ ,g cross-sectional area. In 18 operation, the weir 8, wall 2 and head 3 operate like a hopper to funnel settling 19 cuttings down to the foot of the compartment 12.
The involute feed inlet 6 is positioned over the inlet compartment 12.
The vessel side wall 2 forms a bottom outlet means 13 at the base of the 2 inlet COIllpd~ l 12 between the weir 8 and head 3. A solids auger pump 14 is 3 cul~lle~ d with the outlet means 13, for ~v;;I,d~ .,g cuttings from the inlet 4 compartment 12.
Perforated sparging lines 15 are positioned in the inlet co" ,~.arl",~ ~l 12 6 for injecting water as required to fluidize settled cuttings and assist in moving them 7 to the bottom outlet means 13.
8 A second weir 16 extends upwardly from the bottom of the vessel side 9 wall 2 at about the longitudinal midpoint of the chamber 5. The rim 17 of the second 10 weir 16 is positioned at a lower elevation than the rim 9 of the first weir 8. The two 11 weirs 8 16 and vessel side wall 2 combine to form an i"l~,l"edi~l~ co",uall",el,l 18.
12 A riser 19 extends upwardly into the intermediate cc,ll,palll"el,l 18 and provides an 13 outlet 20 for removal of water. The outlet 20 is positioned below the rim 17. A
14 manway 11 provides access to the i"le""edidLe compartment 18. Capped drains 22 1~ are provided in the bottom of the vessel side wall 2 for removal of flush water and 16 solids when cleaning the il,lt:""e.lial~ compartment 18.
17 A third compartment 23 is defined by the weir 16 side wall 2 and outlet 18 end head 4. A riser 24 extends upwardly into the third compartment 13 and provides 19 an outlet 25 for removal of oil. The outlet 25 is positioned beneath the rim 17. A
manway 26 provides access into the c~" ,parLI l ,~"~ 23. Capped drains 27 are provided 21 in the bottom of the vessel side wall 2, for removal of oil and flush water when cleaning
22 the third compartment 23.
-- =
2~2183~
A gas outlet means 28 extends through the outlet head 4 from the upper 2 end of the vessel chamber 5, for removal of liberated gas.
3 In operation, the under-balanced drilling fluid is introduced into the upper 4 end of the vessel chamber 5 through the feed inlet 6. Turbulence is minimized by slowing the velocity of the incoming feed stream as it advances through the expanding 6 passageway 29 of the feed inlet 6 and by discharging it horizontally. Contained coarse 7 solid cuttings settle downwardly in the inlet compartment 12 and are funnelled down 8 to the bottom outlet means 13. They are withdrawn through the bottom outlet means 9 13 by the auger pump 14. Gas breaks out of the feed as it is delivered to the inlet compartment 12. This gas is removed from the chamber 5 through the gas outlet 11 means 28. Liquid separates and overflows the slanted weir rim 9 and is temporarily 12 retained in the intermediate compartment 12. Fine solids still entrained in the liquid 13 senle out and collect on the bottom of the compartment 18. Oil separates and 14 overflows the rim 17 of the second weir 16. Water is removed from the second or i,lL~l",e-lidl~ compartment 18 through the submerged outlet 20 of the riser 19. The oil 16 entering the third compartment 23 is removed through the submerged outlet 25 of the 17 riser 24. At the co,,,pl~liull of drilling, the fine solids in the intermediate compartment 18 18 can be removed by opening the manway 21 and washing them out through the19 drains 22 with a pressure hose, without entering the vessel chamber 5.
The separator A is characterized by the following advantages:
2~ coarse cuttings can be removed while drilling is underway and 22 returning fluid continues to enter the vessel chamber 5;
~ ~ 1 4 =:
2 ~ 2 ~ 8 3 1 coatse cuttings and fine solids are removed without requiring men 2 to enter the chamber;
3 the need for a vacuum truck, standing by for hours, is eliminated;
4 the hopper-like configuration of the inlet compartment prevents accumulation of cuttings piles; and 6 . the five possible c~",po~ (cuttings, fines, oil, water and gas) 7 of under-balanced drilling fluid are separated and separately 8 recovered.
i .
~ . ~
-- =
2~2183~
A gas outlet means 28 extends through the outlet head 4 from the upper 2 end of the vessel chamber 5, for removal of liberated gas.
3 In operation, the under-balanced drilling fluid is introduced into the upper 4 end of the vessel chamber 5 through the feed inlet 6. Turbulence is minimized by slowing the velocity of the incoming feed stream as it advances through the expanding 6 passageway 29 of the feed inlet 6 and by discharging it horizontally. Contained coarse 7 solid cuttings settle downwardly in the inlet compartment 12 and are funnelled down 8 to the bottom outlet means 13. They are withdrawn through the bottom outlet means 9 13 by the auger pump 14. Gas breaks out of the feed as it is delivered to the inlet compartment 12. This gas is removed from the chamber 5 through the gas outlet 11 means 28. Liquid separates and overflows the slanted weir rim 9 and is temporarily 12 retained in the intermediate compartment 12. Fine solids still entrained in the liquid 13 senle out and collect on the bottom of the compartment 18. Oil separates and 14 overflows the rim 17 of the second weir 16. Water is removed from the second or i,lL~l",e-lidl~ compartment 18 through the submerged outlet 20 of the riser 19. The oil 16 entering the third compartment 23 is removed through the submerged outlet 25 of the 17 riser 24. At the co,,,pl~liull of drilling, the fine solids in the intermediate compartment 18 18 can be removed by opening the manway 21 and washing them out through the19 drains 22 with a pressure hose, without entering the vessel chamber 5.
The separator A is characterized by the following advantages:
2~ coarse cuttings can be removed while drilling is underway and 22 returning fluid continues to enter the vessel chamber 5;
~ ~ 1 4 =:
2 ~ 2 ~ 8 3 1 coatse cuttings and fine solids are removed without requiring men 2 to enter the chamber;
3 the need for a vacuum truck, standing by for hours, is eliminated;
4 the hopper-like configuration of the inlet compartment prevents accumulation of cuttings piles; and 6 . the five possible c~",po~ (cuttings, fines, oil, water and gas) 7 of under-balanced drilling fluid are separated and separately 8 recovered.
i .
~ . ~
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A closed separator for separating the components of under-balanced drilling fluid returning from a well to produce separate streams of solid cuttings, gas, oil and water, when present in the fluid, comprising:
an elongated, horizontal, cylindrical pressure vessel having a side wall and curved heads at its ends which together form a closed internal chamber, said vessel having upstream and downstream ends;
inlet means for introducing the fluid through an aperture into the upper portion of the vessel chamber at its upstream end;
cuttings outlet means, positioned at the bottom of the chamber at its upstream end, for removal of solid cuttings;
a first weir extending upwardly from the bottom and transversely of the chamber, said first weir being slanted away from the upstream end head and being sealed to the vessel sidewall, said first weir having its top rim spaced below the inlet means aperture, the bottom end of the first weir being positioned close to the upstream end head on the downstream side of the cuttings outlet means;
the first weir, side wall and upstream end head combining to form an upstanding first compartment of downwardly diminishing cross-sectional area, said compartment being shaped to funnel settling cuttings down to the cuttings outlet means;
the first compartment being operative to receive the fluid being introduced by the inlet means;
means, connected with the cuttings outlet means, for withdrawing solid cuttings therethrough;
gas outlet means for removing gas from the upper end of the chamber;
water outlet means, downstream of the first weir, having an aperture for removing water that has settled to the bottom end of the chamber; and oil outlet means, downstream of the first weir, having an aperture for removing oil.
an elongated, horizontal, cylindrical pressure vessel having a side wall and curved heads at its ends which together form a closed internal chamber, said vessel having upstream and downstream ends;
inlet means for introducing the fluid through an aperture into the upper portion of the vessel chamber at its upstream end;
cuttings outlet means, positioned at the bottom of the chamber at its upstream end, for removal of solid cuttings;
a first weir extending upwardly from the bottom and transversely of the chamber, said first weir being slanted away from the upstream end head and being sealed to the vessel sidewall, said first weir having its top rim spaced below the inlet means aperture, the bottom end of the first weir being positioned close to the upstream end head on the downstream side of the cuttings outlet means;
the first weir, side wall and upstream end head combining to form an upstanding first compartment of downwardly diminishing cross-sectional area, said compartment being shaped to funnel settling cuttings down to the cuttings outlet means;
the first compartment being operative to receive the fluid being introduced by the inlet means;
means, connected with the cuttings outlet means, for withdrawing solid cuttings therethrough;
gas outlet means for removing gas from the upper end of the chamber;
water outlet means, downstream of the first weir, having an aperture for removing water that has settled to the bottom end of the chamber; and oil outlet means, downstream of the first weir, having an aperture for removing oil.
2. The separator as set forth in claim 1 comprising:
a second weir extending upwardly from the bottom and transversely of the chamber, said weir being sealed to the vessel side wall and having its top rim spaced below the top rim of the first weir, said second weir being spaced downstream from the first weir, thereby combining with the first weir to define a second compartment for collecting fine solids and water and combining with the downstream end head to define a third compartment;
the water outlet means communicating with the second compartment; and the oil outlet means communicating with the third compartment.
a second weir extending upwardly from the bottom and transversely of the chamber, said weir being sealed to the vessel side wall and having its top rim spaced below the top rim of the first weir, said second weir being spaced downstream from the first weir, thereby combining with the first weir to define a second compartment for collecting fine solids and water and combining with the downstream end head to define a third compartment;
the water outlet means communicating with the second compartment; and the oil outlet means communicating with the third compartment.
3. The separator as set forth in claim 1 wherein:
the fluid inlet means comprises an involute structure forming a passageway of increasing cross-section which terminates at the aperture, so that the velocity of the fluid being introduced into the chamber is diminished as it passes through the passageway.
the fluid inlet means comprises an involute structure forming a passageway of increasing cross-section which terminates at the aperture, so that the velocity of the fluid being introduced into the chamber is diminished as it passes through the passageway.
4. The separator as set forth in claim 3 wherein:
the aperture of the involute structure is directed toward the upstream end head.
the aperture of the involute structure is directed toward the upstream end head.
5. The separator as set forth in claim 2 wherein:
the fluid inlet means comprises an involute structure forming a passageway of increasing cross-section which terminates at the aperture, so that the velocity of the fluid being introduced into the chamber is diminished as it passes through the passageway.
the fluid inlet means comprises an involute structure forming a passageway of increasing cross-section which terminates at the aperture, so that the velocity of the fluid being introduced into the chamber is diminished as it passes through the passageway.
6. The separator as set forth in claim 5 wherein:
the aperture of the involute structure is directed toward the upstream end head.
the aperture of the involute structure is directed toward the upstream end head.
7. The separator as set forth in claims 1, 2, 3, 4, 5 or 6 comprising:
means, positioned within the first upstream compartment, for introducing water to fluidize settled cuttings and assist in moving them to the cuttings outlet means.
means, positioned within the first upstream compartment, for introducing water to fluidize settled cuttings and assist in moving them to the cuttings outlet means.
8. A method for separating the components of drilling fluid returning from a well undergoing under-balanced drilling, said fluid being pressurized and comprising coarse cuttings, particulate fine solids, at least one liquid component and gas, comprising:
providing a closed, horizontal pressure vessel forming a chamber having upstream and downstream ends, said vessel having wall means forming an internal upstanding compartment in the chamber at its upstream end, said compartment having a downwardly diminishing cross-sectional area, inlet means for introducing the drilling fluid into the compartment at its upper end, cuttings outlet means at the base of the compartment, gas outlet means and liquid outlet means for separately removing cuttings, liquid components and gas from the vessel, said cuttings outlet means being connected with means for withdrawing cuttings from the compartment, said wall means partly comprising a weir so that liquid may overflow from the compartment into the downstream end of the chamber;
introducing the drilling fluid into the compartment so that the cuttings settle and concentrate downwardly while the liquid overflows the weir and moves into the downstream end of the chamber;
withdrawing the concentrated cuttings from the vessel through the cuttings outlet means using the withdrawal means;
settling fine solids from the overflowed liquid and separately removing each liquid component from the vessel.
providing a closed, horizontal pressure vessel forming a chamber having upstream and downstream ends, said vessel having wall means forming an internal upstanding compartment in the chamber at its upstream end, said compartment having a downwardly diminishing cross-sectional area, inlet means for introducing the drilling fluid into the compartment at its upper end, cuttings outlet means at the base of the compartment, gas outlet means and liquid outlet means for separately removing cuttings, liquid components and gas from the vessel, said cuttings outlet means being connected with means for withdrawing cuttings from the compartment, said wall means partly comprising a weir so that liquid may overflow from the compartment into the downstream end of the chamber;
introducing the drilling fluid into the compartment so that the cuttings settle and concentrate downwardly while the liquid overflows the weir and moves into the downstream end of the chamber;
withdrawing the concentrated cuttings from the vessel through the cuttings outlet means using the withdrawal means;
settling fine solids from the overflowed liquid and separately removing each liquid component from the vessel.
9. The method as set forth in claim 8 comprising:
separately introducing water into the compartment to fluidize solids and assist in moving them to the cuttings outlet means.
separately introducing water into the compartment to fluidize solids and assist in moving them to the cuttings outlet means.
10. The method as set forth in claims 8 or 9 comprising:
separately removing any gas, associated with the drilling fluid, form the vessel.
separately removing any gas, associated with the drilling fluid, form the vessel.
11. A method for separating the components of pressurized drilling fluid returning from a well undergoing drilling, said fluid comprising bit cuttings, liquid and gas, comprising:
introducing the pressurized drilling fluid into a closed pressurized separator means connected with the well;
separating the cuttings, liquid and gas in the separator means;
collecting and concentrating the separated cuttings in the separator means;
withdrawing the collected cuttings from the separator means while pressurized drilling fluid continues to enter the separator means so that drilling is not interrupted; and separately removing each of the gas and liquid from the separator means.
introducing the pressurized drilling fluid into a closed pressurized separator means connected with the well;
separating the cuttings, liquid and gas in the separator means;
collecting and concentrating the separated cuttings in the separator means;
withdrawing the collected cuttings from the separator means while pressurized drilling fluid continues to enter the separator means so that drilling is not interrupted; and separately removing each of the gas and liquid from the separator means.
12. The method as set forth in claim 11 wherein the liquid component comprises hydrocarbons and water and they are separated in the separator means and each is removed from the separator means as a separate stream.
13. The method as set forth in claims 11 or 12 wherein the well is undergoing under-balanced drilling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002121831A CA2121831C (en) | 1994-04-21 | 1994-04-21 | Horizontal separator for treating under-balanced drilling fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002121831A CA2121831C (en) | 1994-04-21 | 1994-04-21 | Horizontal separator for treating under-balanced drilling fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2121831A1 CA2121831A1 (en) | 1995-10-22 |
| CA2121831C true CA2121831C (en) | 1996-12-31 |
Family
ID=4153427
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002121831A Expired - Lifetime CA2121831C (en) | 1994-04-21 | 1994-04-21 | Horizontal separator for treating under-balanced drilling fluid |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2121831C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5900137A (en) * | 1996-06-27 | 1999-05-04 | Homan; Edwin Daryl | Apparatus and method for separating components in well fluids |
| US8945395B2 (en) | 2011-11-29 | 2015-02-03 | Bonavista Energy Corporation | Settling vessel and method of use |
-
1994
- 1994-04-21 CA CA002121831A patent/CA2121831C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2121831A1 (en) | 1995-10-22 |
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