CA1289412C - Fluid driven pumping apparatus - Google Patents
Fluid driven pumping apparatusInfo
- Publication number
- CA1289412C CA1289412C CA000517400A CA517400A CA1289412C CA 1289412 C CA1289412 C CA 1289412C CA 000517400 A CA000517400 A CA 000517400A CA 517400 A CA517400 A CA 517400A CA 1289412 C CA1289412 C CA 1289412C
- Authority
- CA
- Canada
- Prior art keywords
- fluid
- pump
- motor
- housing
- screw
- 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 - Fee Related
Links
- 239000012530 fluid Substances 0.000 title claims abstract description 122
- 238000005086 pumping Methods 0.000 title claims abstract description 21
- 238000006073 displacement reaction Methods 0.000 claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 description 21
- 239000004576 sand Substances 0.000 description 8
- 239000007788 liquid Substances 0.000 description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000010779 crude oil Substances 0.000 description 3
- 238000005461 lubrication Methods 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007792 gaseous phase Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007789 sealing Methods 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
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
- E21B43/129—Adaptations of down-hole pump systems powered by fluid supplied from outside the borehole
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C11/00—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations
- F04C11/001—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations of similar working principle
- F04C11/003—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations of similar working principle having complementary function
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
- F01C13/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
- F01C13/04—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby for driving pumps or compressors
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Rotary Pumps (AREA)
- Details And Applications Of Rotary Liquid Pumps (AREA)
- Control Of The Air-Fuel Ratio Of Carburetors (AREA)
Abstract
A B S T R A C T
FLUID DRIVEN PUMPING APPARATUS
A fluid driven pumping apparatus comprises a housing con-taining a twin rotor screw type positive displacement motor and a twin rotor screw type positive displacement pump. The screw rotors of said pump and motor are mounted on a pair of common shafts.
FLUID DRIVEN PUMPING APPARATUS
A fluid driven pumping apparatus comprises a housing con-taining a twin rotor screw type positive displacement motor and a twin rotor screw type positive displacement pump. The screw rotors of said pump and motor are mounted on a pair of common shafts.
Description
~2894~2 The invention relates to a fluid driven apparatus for pumping a fluid or a mixture of fluids. me invention relates in parti-cular to a fluid driven apparatus for pumping fluids at remote or difficult accessible locations, such as in a well or in a sub-sea flowline.
Apart from jet pumps, which are rather inefficient, presently available fluid driven pumps are generally of the turbine type.
However, turbine pumps employ high fluid velocities and narrow fluid passages which gives rise to a high wear rate and thus to frequent maintenance if the produced fluid is sand bearing.
The invention seeks to provide a compact and reliable fluid driven pumping apparatus which has a low wear rate even if the pro-duced fluid is sand bearing and which can be easily installed in a flow~ine system.
me invention also seeks to provide a fluid driven pumping apparatus which is able to pump both gaseous and liquid fluids or mixtures thereof.
In accordance with the invention there is provided a fluid driven pumping apparatus comprising a twin rotor screw type positive displacement motor having a driving fluid inlet and a driving fluid outlet, and connected to said motor a twin rotor screw type positive displacement pump having a pumped fluid inlet in fluid communication with the driving fluid outlet and having a pumped fluid outlet, the fluid displacement volume of said pump being larger than the fluid displacement volume of said motor, the apparatus further comprising a pair of shafts rotatably mounted in a housing, each shaft carry-ing a screw rotor of said pump and a screw rotor of said motor.
In that the driving fluid outlet is in fluid communication with the pumped fluid inlet, the driving fluid emerging from the motor mixes with the incoming pumped fluid before the combined fluid stream passes into the pump.
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In a suitable embodiment of the invention the screw rotors of said pump and motor which are m~unted on a common shaft are identical in helix angle and pitch diameter. However, the screw rotors of said pump preferably have a larger tip diameter and a correspondingly smaller base diameter than the screw rotors of said m~tor.
The invention will now be described by way of example with reference to the accompanying drawing, in which:
Fig. 1 shows a longitudinal section of a pumping apparatus according to the invention.
Fig. 2 shows a longitudinal section of another pumping apparatus according to the invention.
Fig. 3 is a longitudinal section of the apparatus of Fig. 2 taken along line I-I in Fig. 2 and seen in the direction of arrows III.
Fig. 4 is a cross-section of the aF~paratus of Fig.2 and 3 seen in the direction of arr~ws rv in Fig, 3.
The pumping apparatus shcwn in Fig. 1 comprises a housing 1 enclosed in a protective shell 2. The housing 1 consists of a side wall 3 and upper and lower terminal walls 5 and 6, respectively.
The lower part of the housing contains a m~tor section consisting of a twin rotor screw type positive displacement motor 10, whereas the upper part of the housing contains a pump section consisting of a twin rotor screw type positive displacement pump 11. The motor section 10 ccmprises a pair of cooperating screw rotors lOA and lOB, and the pump section 11 comprises a similar pair of cooperating screw rotors llA and llB. The screw rotors lOA and llA
shown at the left side of the drawing are identical in helix angle and they are mounted on a comm~n shaft 13, whereas the screw rotors lOB and llB shcwn at the right side of the drawing are also identical in helix angle and m~unted on a common shaft 14. The helix angles of the cooperating pairs of screw rotors lOA, lOB and llA, llB, respectively, are opposite to each other and the axes of rotation of the shafts 13 and 14 are parallel to each other.
lZ
-- 3 ~
As illustrated in Fig. 1 the screw rotors llA, llB of the pump and the screw rotors lOA, lOB of the motor have identical pitch radii Rp, but the screw rotors llA, llB of the pump have a larger tip radius and a correspondingly smaller base radius than the screw rotors lOA, lOB of the motor.
me shafts 13 and 14 are supported by bearings 16 in the upper- and lower terminal walls 5, 6.
me bearings 16 may be of any suitable type and it is pre-ferred to lubricate the bearings with clean drive fluid derived from an inlet compartment 17 at the upstream end 18 of the motor.
In order to facilitate lubrication of the bearings 16 in the upper terminal wall 5 the shafts 13 and 14 may each be provided with a bore (not shown) forming a fluid ccmmunication between the said inlet ccnpartient 17 and the bearings 16 in said upper wall 5.
FurthermDre, by means of radial drillings (not shown) in the screw rotors llA, llB, comm~nicating with the bores, clean drive fluid can be introduc~d into close clearance points at the rotor tips, further preventing damage by sand and other erosive matter.
Alternatively, clean drive fluid can be supplied to the bearings 16 in the upper terminal wall 5 through a suitable passage (not shown) in the housing.
During operation of the pumping apparatus driving fluid is injected into the inlet oompart~ert 17 via a driving fluid inlet port 20 passing through the side wall 2 of the apparatus at a location adjacent to the lower housing wall 6. Said injection causes the drive fluid to move in upward direction through the lower compartment 8 towards a ch~mber 21 formed in the middle of the housing 1 between the downstream end 22 of the motor 10 and the upstream end 23 of the pump, thereby actuating the screw rotors lOA, lOB of the motor to rotate in opposite directions, as indicated ,by arrows V. The manner in which the drive fluid actuates the screw rotors lOA, lOB of the twin rotor screw type motor is known per se and does not require a detailed description.
` ~-. ', .
~894~1 2 Said rotation of the screw rotors lOA, lOB of the motor 10 induces the shafts 13, 14 and thus the screw rotors llA, llB of the Pu~? 11 to rotate at the same speed in the direction of arrows V.
l~ue to the large tip diameter and small base diameter of the pump rotors llA, llB in comparison to the motor rotors lOA, lOB, or in other words due to the large displacement volume of the pump 11 in coml?arison to that of the motor 10, the pump rotors llA, llB tend to suck more fluid away fram the chamber 21 than the amount of driving fluid discharged from the motor 10.
This causes pumped fluid to be sucked into the chamber via a production fluid inlet 24 formed in the side wall 3 of the housing and to be subsequently pumped together with the driving fluid in upward direction by the pump rotors llA, llB towards a pumped fluid outlet 25 formed near the upper terminal wall 5.
The pumping apparatus shown in Fig. 1 may be used to pump single- or multiphase fluids such as muxture of hydrocarbon fluids containing crude oil and natural gas, while the pumped fluids may contain solid particles, such as sand, without giving rise to a largely increased ~ear rate of the apparatus. If the pumped fluid mainly consists of a liquid, it is preferred to use recirculated pumped fluid as driving fluid and to filter solid particles such as sand from the pumped fluid before reinjecting it into the driving fluid inlet 20 of the apparatus as a clean driving fluid. The reinjected pumped fluid may be mixed up with other fluids or lubricants if the viscosity of the pumped fluid is too high to allow it to be used as driving fluid.
If the pumped fluid consists of a gas-liquid mixture it is preferred to separate the liquid phase from the gaseous phase and to use the liquid phase as driving fluid. If the pumped fluid mainly consists of a gas it is preferred to use a liquid as driving fluid. This would enable sufficient lubrication of the bearings 16 and rotor tips 19 and would further provide sufficient m mim~m flow of liquid through the pump to enable the pump to continue to develop its full differential pres Æ e.
It will be appreciated by those skilled in the art that , .
1~899~2 instead of arranging the shafts parallel to each other as shown in F'ig. 1, the shafts may also be arranged at an angle relative to each other, provided that the screw rotors of the pump and motor have a suitable shape.
The pumping apparatus shcwn in Figures 2-4 comprises a housing 31 with a longitudinal axis I-I and a side wall 32 having a cylindrical outer surfaoe 33 arranged co-axial to said axis I-I. On the outer surface 33 of the side wall 32 there are mounted two inflatable packers 34 or other suitable devices for securing ]o the apparatus at a selected downhole location inside a production string (not shcwn) within a well from which a fluid, such as crude oil, is produced. The housing 31 further comprises upper and lower terminal walls 35 and 36, respectively, and an intermediate wall 37, which walls are substantially flat and arranged cross-axial to the longitudinal axis I-I. me intermediate wall 37 is located in the middle of the housing 31 and divides the housing interior into an lpper ccmpartment 38 and a lower ccmpartment 39. The upper housing compartment 38 comprises the motor section consisting of a twin rotor screw type positive displacement motor 40, whereas the lower housing ccmpartment 39 comprises the pump section consisting of a twin rotor screw type positive displacement pump 41. The motor section 40 ccmprises a pair of cooperating screw rotors 40A and 40B, and the pump section 41 comprises a similar pair of cooper-ating screw rotors 41A and 41B. The screw rotors 40A and 41A shcwn at the left side of Fig. 2 are identical in diameter and helix angle and they are mounted on a common shaft 43, whereas the screw rotors 40B and 41B shcwn at the right side of Fig. 2 are also ~- identical in diameter and helix angle and mLunted on a commDn shaft 44. The helix angles of the cooperating pairs of screw rotors 40A, 40B and 41A, 41B, respectively, are opposite to each okher and the axes of rotation of the shafts 43 and 44 are parallel to each other and to the longitudinal axis I-I.
The shafts 43 and 44 are supported by bearings 46 in the upper- and lcwer terminal walls 35, 36 and pierce through cpenings 47 in the intermediate wall 37. The openings 47 may be provided , - -- , : ' , ., ~. ., : ' ,. . ....... .. .
,.,: . ~ ", , , - : , ,. .-:
1~94~2 with sealing rings (not shown) to avoid fluid leakage between the upper- and lower compartment 38 and 39 and they further may comprise a bearing assembly (not shown) for laterally supporting the shafts 43, 44.
The bearing assembly and the bearings 46 may be of any suitable type and it is preferred to lubricate the bearings with clean drive fluid derived from the upper-motor-ccmpartm,nt 38. In order to facilitate lubrication of the bearings 46 in the lower terminal wall 36 the shafts 43 and 44 are each prc~rided with a bore ]o 48 formlng a fluid ccmmunication between the upper cc}partment 38 and the bearings 46 in said lower wall 36. Alternatively clean drive fluid can be supplied to the lower bearings 46 through a suitable passage (not shown) in the housing. Furtherm~re, by means of drillings (not shown) in the screw rotors 41A, 41B, communi-cating with the bores 48, clean drive fluid can be introduced into close clearance points at the rotor tips, further preventing damage bY sand and other erosive matter.
As the pairs of screw rotors 40A, 41A and 40B, 41B mounted on each shaft 43, 44 are identical in diameter and helix angle, the axial thrusts are inherently in balance thus avoiding a substantial thrust bearing on the shafts 43, 44.
During normal operation of the pumping apparatus in a well, driving fluid is injected into the upper ccmpartment 38 via a driving fluid inlet port 50 passing through the side wall 32 of the apparatus 31 at a location immediately above the intermediate wall 37. Said injection causes the drive fluid to mave in upward ~-rection through the upper ccmpartment 38 towards a pair of driving fluid outlet ports 52 in the upper terminal wall 35, thereby actuating the screw rotors 40A, 40B of the mDtor, and simultaneously the shafts 43, 44 and screw rotors 41A, 41B, to rotate in opposite directions, as indicated by arrows VI. The manner in which the drive fluid actuates the screw rotors 40A, 40B
of the twin rotor screw tyF~ m~tor is kncwn per se and dces not require a detailed description.
Said rotation of the screw rotors 41A, 41B of the screw pump ' . ' , ' ' , .. . .
.
12~39~2 41 induces well fluid to be sucked into the lower ccmpartment 39 via a pair of production fluid inlets 54 in the lower terminal wall 36 and to be subsequently pumped in upward direction through the lower conpartment towards a production fluid outlet consisting of a conduit 55 discharging into the interior of the production tubing section (not shown) above the upper terminal wall 35. As illustrated in Fig. 3 and 4 the conduit 55 forms a by-pass along the upper compartment 38 of the apparatus and ccmprises a radial section 55A which is in fluid communication with the section of the interior of the lower ocmpartmEnt 39 adjacent to the intermediate wall 37 and an axial section 55B extending through a longitudinal bore irl the side wall 31 of the housing.
The apparatus is installed in a production tubing (not shown) of a well in the following manner. The apparatus is connected to a wirèline tool and lowered through the tubing to a selected depth where an opening has been shot through the tubing wall, which opening forms a fluid passage from an annular space surrounding the tubing and the tubing interior, The apparatus is subsequently anchored to the tubing wall by inflating the packers 34 on the side wall 32 thereof after checking that said opening in the tubing wall is located between the packers 34. In this m~nner the driving fluid inlet S0 is brought in fluid communication with the annular space around the tubing, while the apparatus divides the interior of the tubing in a lower tubing section extending between the well pro-duction zone and the lcwer terminal wall 36 of the apparatus and anupper tubing section extending from the upper terminal wall 35 of the apparatus towards the wellhead, Alternatively the apparatus may ~be located and supported in the production tubing by allownng it to rest on suitably located projections arranged in the base of the said tubing, After having thus installed the apparatus in the well tubing the apparatus is disconnected from the wireIine tool and pumping is started by injecting a drive fluid by pumping means located at the well head via the annular space and said opening in the tubing wall into the driving fluid inlet 50, thereby activating the screw ~::
:
.
, .
.
- . - . ' ~
~2~394~2 rotors 40A, 40B of the motor section 40 to rotate the shafts and the screw rotors 41A, 41B of the pump section 41 in the directions illustrated by arrows VI. As described hereinbefore, said rotation causes the screw rotors 41A, 41B of the pump section 41 to suck the well fluids from the lower tubing section via the production fluid inlet ports 54 into the lower comparbment 39 and to subsequently pump the well fluids in upward direction via the production fluid outlet 55 into the upper tubing section located above the apparatus 31. In the upper tubing section the production fluid is mixed with the drive fluid and transferred to the wellhead. It is preferred to use recirculated production fluid as driving fluid and to filter solid particles such as sand from the production fluid before reinjecting it into the well as a clean driving fluid. The re-injected production fluid may be mixed up with other fluids such as gasoline if the viscosity of the produced fluid is too high to allow it to be used as driving fluid. If the produced fluid is not suitable to ~e used as driving fluid then the driving fluid should not be mixed up with the production fluid in the production string, but should be transferred back to the wellhead via a ser~rate return conduit connected to the driving fluid outlet 51 of the apparatus and located in the interior of the production tubing.
Mbreover, instead of using the well annulus as conduit for injecting driving fluid, a separate supply conduit may be installed in the production tubing to supply the driving fluid to the apparatus. In this manner a closed circuit can be created through which drive fluid is circulated from the pumping means at the wellhead to the dcwnhole pumping apparatus and vice versa. The driving fluid supply and exhaust conduits that form the circuit may be suspended within the production tubing as a pair of co-axial pipes.
As illustrated in Figures 3 and 4 the apparatus is provided with a longitudinal passage 60 to enable lawering and raising of wirelme tools through the production tubing to the production zone while the apparatus 31 is present inside the tubing. The longitudinal passage 60 extends through a bore in the side wall 32 of the .. . .
-~ ~
-~ ' 1289~112 apparatus and is provided near the upper end ~hereof with a plug 61 which can be rem~ved when a wireline tool is lowered through the tubing. If desired, the rem~vable plug 61 may be replaced by a valve (not shown3 which is nonmally open but closes autcmatically if the apparatus is activated to pump well fluids to the surface.
The pumping apparatus according to the invention may be used to pump single- or multiphase fluids such as mixture of hydrocarbon fluids containing crude oil and natural gas, while the produced fluids may contain solid particles, such as sand, without giving rise to a largely increased wear rate of the apparatus.
, ~ ~ .
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', : : , , ' ' : , , ~, ' ' , , : ' ' ' ' ~ : ' - ' : : , :
Apart from jet pumps, which are rather inefficient, presently available fluid driven pumps are generally of the turbine type.
However, turbine pumps employ high fluid velocities and narrow fluid passages which gives rise to a high wear rate and thus to frequent maintenance if the produced fluid is sand bearing.
The invention seeks to provide a compact and reliable fluid driven pumping apparatus which has a low wear rate even if the pro-duced fluid is sand bearing and which can be easily installed in a flow~ine system.
me invention also seeks to provide a fluid driven pumping apparatus which is able to pump both gaseous and liquid fluids or mixtures thereof.
In accordance with the invention there is provided a fluid driven pumping apparatus comprising a twin rotor screw type positive displacement motor having a driving fluid inlet and a driving fluid outlet, and connected to said motor a twin rotor screw type positive displacement pump having a pumped fluid inlet in fluid communication with the driving fluid outlet and having a pumped fluid outlet, the fluid displacement volume of said pump being larger than the fluid displacement volume of said motor, the apparatus further comprising a pair of shafts rotatably mounted in a housing, each shaft carry-ing a screw rotor of said pump and a screw rotor of said motor.
In that the driving fluid outlet is in fluid communication with the pumped fluid inlet, the driving fluid emerging from the motor mixes with the incoming pumped fluid before the combined fluid stream passes into the pump.
C
` ~Z~94~Z
In a suitable embodiment of the invention the screw rotors of said pump and motor which are m~unted on a common shaft are identical in helix angle and pitch diameter. However, the screw rotors of said pump preferably have a larger tip diameter and a correspondingly smaller base diameter than the screw rotors of said m~tor.
The invention will now be described by way of example with reference to the accompanying drawing, in which:
Fig. 1 shows a longitudinal section of a pumping apparatus according to the invention.
Fig. 2 shows a longitudinal section of another pumping apparatus according to the invention.
Fig. 3 is a longitudinal section of the apparatus of Fig. 2 taken along line I-I in Fig. 2 and seen in the direction of arrows III.
Fig. 4 is a cross-section of the aF~paratus of Fig.2 and 3 seen in the direction of arr~ws rv in Fig, 3.
The pumping apparatus shcwn in Fig. 1 comprises a housing 1 enclosed in a protective shell 2. The housing 1 consists of a side wall 3 and upper and lower terminal walls 5 and 6, respectively.
The lower part of the housing contains a m~tor section consisting of a twin rotor screw type positive displacement motor 10, whereas the upper part of the housing contains a pump section consisting of a twin rotor screw type positive displacement pump 11. The motor section 10 ccmprises a pair of cooperating screw rotors lOA and lOB, and the pump section 11 comprises a similar pair of cooperating screw rotors llA and llB. The screw rotors lOA and llA
shown at the left side of the drawing are identical in helix angle and they are mounted on a comm~n shaft 13, whereas the screw rotors lOB and llB shcwn at the right side of the drawing are also identical in helix angle and m~unted on a common shaft 14. The helix angles of the cooperating pairs of screw rotors lOA, lOB and llA, llB, respectively, are opposite to each other and the axes of rotation of the shafts 13 and 14 are parallel to each other.
lZ
-- 3 ~
As illustrated in Fig. 1 the screw rotors llA, llB of the pump and the screw rotors lOA, lOB of the motor have identical pitch radii Rp, but the screw rotors llA, llB of the pump have a larger tip radius and a correspondingly smaller base radius than the screw rotors lOA, lOB of the motor.
me shafts 13 and 14 are supported by bearings 16 in the upper- and lower terminal walls 5, 6.
me bearings 16 may be of any suitable type and it is pre-ferred to lubricate the bearings with clean drive fluid derived from an inlet compartment 17 at the upstream end 18 of the motor.
In order to facilitate lubrication of the bearings 16 in the upper terminal wall 5 the shafts 13 and 14 may each be provided with a bore (not shown) forming a fluid ccmmunication between the said inlet ccnpartient 17 and the bearings 16 in said upper wall 5.
FurthermDre, by means of radial drillings (not shown) in the screw rotors llA, llB, comm~nicating with the bores, clean drive fluid can be introduc~d into close clearance points at the rotor tips, further preventing damage by sand and other erosive matter.
Alternatively, clean drive fluid can be supplied to the bearings 16 in the upper terminal wall 5 through a suitable passage (not shown) in the housing.
During operation of the pumping apparatus driving fluid is injected into the inlet oompart~ert 17 via a driving fluid inlet port 20 passing through the side wall 2 of the apparatus at a location adjacent to the lower housing wall 6. Said injection causes the drive fluid to move in upward direction through the lower compartment 8 towards a ch~mber 21 formed in the middle of the housing 1 between the downstream end 22 of the motor 10 and the upstream end 23 of the pump, thereby actuating the screw rotors lOA, lOB of the motor to rotate in opposite directions, as indicated ,by arrows V. The manner in which the drive fluid actuates the screw rotors lOA, lOB of the twin rotor screw type motor is known per se and does not require a detailed description.
` ~-. ', .
~894~1 2 Said rotation of the screw rotors lOA, lOB of the motor 10 induces the shafts 13, 14 and thus the screw rotors llA, llB of the Pu~? 11 to rotate at the same speed in the direction of arrows V.
l~ue to the large tip diameter and small base diameter of the pump rotors llA, llB in comparison to the motor rotors lOA, lOB, or in other words due to the large displacement volume of the pump 11 in coml?arison to that of the motor 10, the pump rotors llA, llB tend to suck more fluid away fram the chamber 21 than the amount of driving fluid discharged from the motor 10.
This causes pumped fluid to be sucked into the chamber via a production fluid inlet 24 formed in the side wall 3 of the housing and to be subsequently pumped together with the driving fluid in upward direction by the pump rotors llA, llB towards a pumped fluid outlet 25 formed near the upper terminal wall 5.
The pumping apparatus shown in Fig. 1 may be used to pump single- or multiphase fluids such as muxture of hydrocarbon fluids containing crude oil and natural gas, while the pumped fluids may contain solid particles, such as sand, without giving rise to a largely increased ~ear rate of the apparatus. If the pumped fluid mainly consists of a liquid, it is preferred to use recirculated pumped fluid as driving fluid and to filter solid particles such as sand from the pumped fluid before reinjecting it into the driving fluid inlet 20 of the apparatus as a clean driving fluid. The reinjected pumped fluid may be mixed up with other fluids or lubricants if the viscosity of the pumped fluid is too high to allow it to be used as driving fluid.
If the pumped fluid consists of a gas-liquid mixture it is preferred to separate the liquid phase from the gaseous phase and to use the liquid phase as driving fluid. If the pumped fluid mainly consists of a gas it is preferred to use a liquid as driving fluid. This would enable sufficient lubrication of the bearings 16 and rotor tips 19 and would further provide sufficient m mim~m flow of liquid through the pump to enable the pump to continue to develop its full differential pres Æ e.
It will be appreciated by those skilled in the art that , .
1~899~2 instead of arranging the shafts parallel to each other as shown in F'ig. 1, the shafts may also be arranged at an angle relative to each other, provided that the screw rotors of the pump and motor have a suitable shape.
The pumping apparatus shcwn in Figures 2-4 comprises a housing 31 with a longitudinal axis I-I and a side wall 32 having a cylindrical outer surfaoe 33 arranged co-axial to said axis I-I. On the outer surface 33 of the side wall 32 there are mounted two inflatable packers 34 or other suitable devices for securing ]o the apparatus at a selected downhole location inside a production string (not shcwn) within a well from which a fluid, such as crude oil, is produced. The housing 31 further comprises upper and lower terminal walls 35 and 36, respectively, and an intermediate wall 37, which walls are substantially flat and arranged cross-axial to the longitudinal axis I-I. me intermediate wall 37 is located in the middle of the housing 31 and divides the housing interior into an lpper ccmpartment 38 and a lower ccmpartment 39. The upper housing compartment 38 comprises the motor section consisting of a twin rotor screw type positive displacement motor 40, whereas the lower housing ccmpartment 39 comprises the pump section consisting of a twin rotor screw type positive displacement pump 41. The motor section 40 ccmprises a pair of cooperating screw rotors 40A and 40B, and the pump section 41 comprises a similar pair of cooper-ating screw rotors 41A and 41B. The screw rotors 40A and 41A shcwn at the left side of Fig. 2 are identical in diameter and helix angle and they are mounted on a common shaft 43, whereas the screw rotors 40B and 41B shcwn at the right side of Fig. 2 are also ~- identical in diameter and helix angle and mLunted on a commDn shaft 44. The helix angles of the cooperating pairs of screw rotors 40A, 40B and 41A, 41B, respectively, are opposite to each okher and the axes of rotation of the shafts 43 and 44 are parallel to each other and to the longitudinal axis I-I.
The shafts 43 and 44 are supported by bearings 46 in the upper- and lcwer terminal walls 35, 36 and pierce through cpenings 47 in the intermediate wall 37. The openings 47 may be provided , - -- , : ' , ., ~. ., : ' ,. . ....... .. .
,.,: . ~ ", , , - : , ,. .-:
1~94~2 with sealing rings (not shown) to avoid fluid leakage between the upper- and lower compartment 38 and 39 and they further may comprise a bearing assembly (not shown) for laterally supporting the shafts 43, 44.
The bearing assembly and the bearings 46 may be of any suitable type and it is preferred to lubricate the bearings with clean drive fluid derived from the upper-motor-ccmpartm,nt 38. In order to facilitate lubrication of the bearings 46 in the lower terminal wall 36 the shafts 43 and 44 are each prc~rided with a bore ]o 48 formlng a fluid ccmmunication between the upper cc}partment 38 and the bearings 46 in said lower wall 36. Alternatively clean drive fluid can be supplied to the lower bearings 46 through a suitable passage (not shown) in the housing. Furtherm~re, by means of drillings (not shown) in the screw rotors 41A, 41B, communi-cating with the bores 48, clean drive fluid can be introduced into close clearance points at the rotor tips, further preventing damage bY sand and other erosive matter.
As the pairs of screw rotors 40A, 41A and 40B, 41B mounted on each shaft 43, 44 are identical in diameter and helix angle, the axial thrusts are inherently in balance thus avoiding a substantial thrust bearing on the shafts 43, 44.
During normal operation of the pumping apparatus in a well, driving fluid is injected into the upper ccmpartment 38 via a driving fluid inlet port 50 passing through the side wall 32 of the apparatus 31 at a location immediately above the intermediate wall 37. Said injection causes the drive fluid to mave in upward ~-rection through the upper ccmpartment 38 towards a pair of driving fluid outlet ports 52 in the upper terminal wall 35, thereby actuating the screw rotors 40A, 40B of the mDtor, and simultaneously the shafts 43, 44 and screw rotors 41A, 41B, to rotate in opposite directions, as indicated by arrows VI. The manner in which the drive fluid actuates the screw rotors 40A, 40B
of the twin rotor screw tyF~ m~tor is kncwn per se and dces not require a detailed description.
Said rotation of the screw rotors 41A, 41B of the screw pump ' . ' , ' ' , .. . .
.
12~39~2 41 induces well fluid to be sucked into the lower ccmpartment 39 via a pair of production fluid inlets 54 in the lower terminal wall 36 and to be subsequently pumped in upward direction through the lower conpartment towards a production fluid outlet consisting of a conduit 55 discharging into the interior of the production tubing section (not shown) above the upper terminal wall 35. As illustrated in Fig. 3 and 4 the conduit 55 forms a by-pass along the upper compartment 38 of the apparatus and ccmprises a radial section 55A which is in fluid communication with the section of the interior of the lower ocmpartmEnt 39 adjacent to the intermediate wall 37 and an axial section 55B extending through a longitudinal bore irl the side wall 31 of the housing.
The apparatus is installed in a production tubing (not shown) of a well in the following manner. The apparatus is connected to a wirèline tool and lowered through the tubing to a selected depth where an opening has been shot through the tubing wall, which opening forms a fluid passage from an annular space surrounding the tubing and the tubing interior, The apparatus is subsequently anchored to the tubing wall by inflating the packers 34 on the side wall 32 thereof after checking that said opening in the tubing wall is located between the packers 34. In this m~nner the driving fluid inlet S0 is brought in fluid communication with the annular space around the tubing, while the apparatus divides the interior of the tubing in a lower tubing section extending between the well pro-duction zone and the lcwer terminal wall 36 of the apparatus and anupper tubing section extending from the upper terminal wall 35 of the apparatus towards the wellhead, Alternatively the apparatus may ~be located and supported in the production tubing by allownng it to rest on suitably located projections arranged in the base of the said tubing, After having thus installed the apparatus in the well tubing the apparatus is disconnected from the wireIine tool and pumping is started by injecting a drive fluid by pumping means located at the well head via the annular space and said opening in the tubing wall into the driving fluid inlet 50, thereby activating the screw ~::
:
.
, .
.
- . - . ' ~
~2~394~2 rotors 40A, 40B of the motor section 40 to rotate the shafts and the screw rotors 41A, 41B of the pump section 41 in the directions illustrated by arrows VI. As described hereinbefore, said rotation causes the screw rotors 41A, 41B of the pump section 41 to suck the well fluids from the lower tubing section via the production fluid inlet ports 54 into the lower comparbment 39 and to subsequently pump the well fluids in upward direction via the production fluid outlet 55 into the upper tubing section located above the apparatus 31. In the upper tubing section the production fluid is mixed with the drive fluid and transferred to the wellhead. It is preferred to use recirculated production fluid as driving fluid and to filter solid particles such as sand from the production fluid before reinjecting it into the well as a clean driving fluid. The re-injected production fluid may be mixed up with other fluids such as gasoline if the viscosity of the produced fluid is too high to allow it to be used as driving fluid. If the produced fluid is not suitable to ~e used as driving fluid then the driving fluid should not be mixed up with the production fluid in the production string, but should be transferred back to the wellhead via a ser~rate return conduit connected to the driving fluid outlet 51 of the apparatus and located in the interior of the production tubing.
Mbreover, instead of using the well annulus as conduit for injecting driving fluid, a separate supply conduit may be installed in the production tubing to supply the driving fluid to the apparatus. In this manner a closed circuit can be created through which drive fluid is circulated from the pumping means at the wellhead to the dcwnhole pumping apparatus and vice versa. The driving fluid supply and exhaust conduits that form the circuit may be suspended within the production tubing as a pair of co-axial pipes.
As illustrated in Figures 3 and 4 the apparatus is provided with a longitudinal passage 60 to enable lawering and raising of wirelme tools through the production tubing to the production zone while the apparatus 31 is present inside the tubing. The longitudinal passage 60 extends through a bore in the side wall 32 of the .. . .
-~ ~
-~ ' 1289~112 apparatus and is provided near the upper end ~hereof with a plug 61 which can be rem~ved when a wireline tool is lowered through the tubing. If desired, the rem~vable plug 61 may be replaced by a valve (not shown3 which is nonmally open but closes autcmatically if the apparatus is activated to pump well fluids to the surface.
The pumping apparatus according to the invention may be used to pump single- or multiphase fluids such as mixture of hydrocarbon fluids containing crude oil and natural gas, while the produced fluids may contain solid particles, such as sand, without giving rise to a largely increased wear rate of the apparatus.
, ~ ~ .
: ~ ::: :
:: :
: ~, ,, :
~ !
', : : , , ' ' : , , ~, ' ' , , : ' ' ' ' ~ : ' - ' : : , :
Claims (6)
1. Fluid driven pumping apparatus comprising a twin rotor screw type positive displacement motor having a driving fluid inlet and a driving fluid outlet, and connected to said motor a twin rotor screw type positive displacement pump having a pumped fluid inlet in fluid communication with the driving fluid outlet and having a pumped fluid outlet, the fluid displacement volume of said pump being larger than the fluid displacement volume of said motor, the apparatus further comprising a pair of shafts rotatably mounted in a housing, each shaft carrying a screw rotor of said pump and a screw rotor of said motor.
2. The apparatus of claim 1, wherein said shafts are parallel to each other and the screw rotors of said pump and motor which are mounted on a common shaft are identical in pitch diameter and helix angle.
3. The apparatus of claim 2, wherein the screw rotors of said pump have a larger tip diameter and a correspondingly smaller base diameter than the screw rotors of said motor.
4. The apparatus of claim 1, wherein the driving fluid outlet consists of a chamber formed in the interior of the housing between said motor and said pump.
5. The apparatus of claim 4, wherein the pumped fluid inlet consists of a port opening formed in the housing wall, which port opening discharges into said chamber.
6. The apparatus of claim 1, wherein the driving fluid inlet is located near one end of the housing and the pumped fluid outlet is located near an opposite end of the housing.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB858521978A GB8521978D0 (en) | 1985-09-04 | 1985-09-04 | Pumping well fluids |
| GB8521978 | 1985-09-04 | ||
| GB868605033A GB8605033D0 (en) | 1986-02-28 | 1986-02-28 | Fluid driven pumping apparatus |
| GB8605033 | 1986-02-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1289412C true CA1289412C (en) | 1991-09-24 |
Family
ID=26289729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000517400A Expired - Fee Related CA1289412C (en) | 1985-09-04 | 1986-09-03 | Fluid driven pumping apparatus |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0216406B1 (en) |
| AU (1) | AU595828B2 (en) |
| CA (1) | CA1289412C (en) |
| DE (1) | DE3680621D1 (en) |
| NO (1) | NO171028C (en) |
| SG (1) | SG69692G (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2357887C (en) | 2001-09-28 | 2006-07-04 | Pradeep Dass | Method of adapting a downhole multi-phase twin screw pump for use in wells having a high gas content and a downhole multi-phase twin screw pump |
| GB0210018D0 (en) * | 2002-05-01 | 2002-06-12 | Univ City | Plural-screw machines |
| US7401655B2 (en) * | 2005-07-07 | 2008-07-22 | Baker Hughes Incorporated | Downhole gas compressor |
| EP2216501A1 (en) * | 2009-02-10 | 2010-08-11 | BP Exploration Operating Company Limited | Pump |
| DE102014000846A1 (en) | 2014-01-27 | 2015-07-30 | Klaus Union Gmbh & Co. Kg | Screw Pump |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1702838A (en) * | 1927-12-30 | 1929-02-19 | Sullivan Machinery Co | Combined mechanical and air-lift pumping system |
| US2269189A (en) * | 1939-03-20 | 1942-01-06 | Harold R Downs | Fluid pump |
| US2804260A (en) * | 1949-07-11 | 1957-08-27 | Svenska Rotor Maskiner Ab | Engines of screw rotor type |
| US3184155A (en) * | 1963-04-17 | 1965-05-18 | Cooper Bessemer Corp | Motor compressor unit |
| US4292011A (en) * | 1979-08-20 | 1981-09-29 | Kobe, Inc. | Turbo pump gas compressor |
| US4386654A (en) * | 1981-05-11 | 1983-06-07 | Becker John A | Hydraulically operated downhole oil well pump |
| DE3409970C1 (en) * | 1984-03-19 | 1985-07-18 | Norton Christensen, Inc., Salt Lake City, Utah | Device for conveying flowable substances |
-
1986
- 1986-08-15 DE DE8686201423T patent/DE3680621D1/en not_active Expired - Fee Related
- 1986-08-15 EP EP86201423A patent/EP0216406B1/en not_active Expired - Lifetime
- 1986-09-02 AU AU62153/86A patent/AU595828B2/en not_active Ceased
- 1986-09-02 NO NO86863514A patent/NO171028C/en unknown
- 1986-09-03 CA CA000517400A patent/CA1289412C/en not_active Expired - Fee Related
-
1992
- 1992-07-03 SG SG696/92A patent/SG69692G/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU595828B2 (en) | 1990-04-12 |
| AU6215386A (en) | 1987-03-05 |
| SG69692G (en) | 1992-09-04 |
| EP0216406B1 (en) | 1991-07-31 |
| NO863514L (en) | 1987-03-05 |
| EP0216406A1 (en) | 1987-04-01 |
| NO863514D0 (en) | 1986-09-02 |
| DE3680621D1 (en) | 1991-09-05 |
| NO171028C (en) | 1993-01-13 |
| NO171028B (en) | 1992-10-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |