CA1311681C - Sand tool - Google Patents
Sand toolInfo
- Publication number
- CA1311681C CA1311681C CA000564133A CA564133A CA1311681C CA 1311681 C CA1311681 C CA 1311681C CA 000564133 A CA000564133 A CA 000564133A CA 564133 A CA564133 A CA 564133A CA 1311681 C CA1311681 C CA 1311681C
- Authority
- CA
- Canada
- Prior art keywords
- cleanout
- production tubing
- tool
- pack
- production
- 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
Links
- 239000004576 sand Substances 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 80
- 239000012530 fluid Substances 0.000 claims abstract description 38
- 238000000034 method Methods 0.000 claims abstract description 30
- 239000013618 particulate matter Substances 0.000 claims abstract description 23
- 238000005086 pumping Methods 0.000 claims abstract description 16
- 239000003129 oil well Substances 0.000 claims abstract description 12
- 238000003780 insertion Methods 0.000 claims abstract description 5
- 230000037431 insertion Effects 0.000 claims abstract description 5
- 210000002445 nipple Anatomy 0.000 claims description 17
- 238000007789 sealing Methods 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 abstract description 10
- 229910000831 Steel Inorganic materials 0.000 abstract description 3
- 239000010959 steel Substances 0.000 abstract description 3
- 239000003921 oil Substances 0.000 description 7
- 238000009434 installation Methods 0.000 description 3
- 239000000295 fuel oil Substances 0.000 description 2
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B37/00—Methods or apparatus for cleaning boreholes or wells
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for cleanout of particulate matter for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous steel rod mounted on a co-rod rig, comprises the steps of withdrawal of the pumping means to the land surface, the connection to said rod of a cleanout tool of predetermined length, the insertion of said tool into said production tubing and substantially simultaneous pumping of a cleanout fluid through said production tubing, said fluid is thereby forced through perforations in said tool and downwards to particulate matter in a lower portion of said production tubing, and thence upwards with said matter in an annulus within said production casing and surrounding said production tubing. The method includes provision for the reverse flow of the cleaning fluid. A tool for said cleanout method comprises a perforated tubular upper section, a central tubular section to which is attached at least one pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tuning.
A method for cleanout of particulate matter for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous steel rod mounted on a co-rod rig, comprises the steps of withdrawal of the pumping means to the land surface, the connection to said rod of a cleanout tool of predetermined length, the insertion of said tool into said production tubing and substantially simultaneous pumping of a cleanout fluid through said production tubing, said fluid is thereby forced through perforations in said tool and downwards to particulate matter in a lower portion of said production tubing, and thence upwards with said matter in an annulus within said production casing and surrounding said production tubing. The method includes provision for the reverse flow of the cleaning fluid. A tool for said cleanout method comprises a perforated tubular upper section, a central tubular section to which is attached at least one pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tuning.
Description
~31 1681 This invention relates to a cleanout method for oil wells, in particular wells producing heavy oil. Such wells incorporate features to prevent the entry of particulate matter such as sand, but do not entirely eliminate such matter, which tends to accumulate at the lower end of the well casing, eventually requiring a time consuming cleanout operation.
Wells producing heavy oil typically comprise an outer production casing, which is cemented into place from the surface to just below the oil producing horizon. This casing is perforated, generally by means of explosive charges, to allow oil to enter. A liner, generally having a welded closed bottom (known as a bullnose), is suspended in the lower portion of the casing, from a liner hanger.
The liner itself has perforations such as slots, to permit the entry of oil, and to restrict the entry of sand or similar matter.
When the liner is in place, a service rig is used to lower an open ended production tubing within the production casing and within the liner, where it is set with the bottom of the tubing about three meters above the bullnosed bottom of the liner. This distance of about three metres facilitates the accumulation and retention of any sand which does enter the liner, rather than permitting it to be drawn into the pump, which is located adjacent to the bottom of the tubing, seated by a seating m~ans.
After the production tubing is set in place, the service rig can be removed, and an operating rig, known as a Co-rod* rig, is moved onto the well, to lower into place a continuous steel rod, at the lower end of which is attached the pump~ The co-rod rig itself is then removed to be replaced by a pump jack for operating the pump to remove the oil.
Despite the design of the liner and the production *Trade-mark tubing, eventually sand and similar matter accumulates to such an extent as to impede the operation of the pump, ultimately causing seizure. At this point, the sand must be cleaned out. The present method involves the re-installation of the co-rod rig to remove the co-rod and the pump from the well, and thereafter, removal of the co-rod rig and installation of the service rig back onto the well to pick up the tubing. For this operation, extra tubing may be added to reach the accumulated matter in the bullnose. Fluid is then pumped into the production tubing, to wash the accumulated matter up to the surface in the annulus between the production tubing and the production casing.
In addition, if the well is under pressure, this pressure must be killed before the extra tubing is added and the cleaning fluid pumped into the well. This is achieved either by the use of known heavy killing fluids, or by the use of a known snubbing unit.
When the accumulated matter has been removed, the extra tubing can be removed, the service rig moved off the well and the co-rod rig is used once again to replace the co-rod and pump. The co-rod rig is in turn replaced by the pump jack for the resumption of the pumping operation.
The present system of cleaning such oil wells suffers from several disadvantages. In particular, there is considerable downtime for production from the well by reason of the time taken to remove the co-rod rig, rod and pump from the vicinity of the well, and to enable the installation of the service rig and extra tubingO During this downtime, pressure problems may arise. In addition, ;there is an inherent increased safety risk involved each time the rigs are exchanged.
; The present invention therefore provides a cleanout method to overcome these disadvantages, by utilizing a simple cleanout tool which requires reduced downtime for the operation of the well, by use only of the -,' '. ~ ;
~ , :
'.
, ~
, 2a 1 31 1 681 co-rod rig, and not necessitating the use of a service rig.
Efficiency and safety are thereby considerably enhanced.
In addition, the tool can include means for enabling the reverse flow of the cleaning fluid, where ~ ~, ~.;: '' ' ::
.
, 3 131 1~81 desirable.
This invention therefore provides a method for particulate matter cleanout for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous rod mounted on a co-rod rig, comprising the following steps, withdrawal of the pumping means to the land surface, connection to the rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within ~he production tubing adjacent the outside of the tool, and a lower tubular section, tha tubular sections having an external diameter less than the internal diameter of the production tubing, insertion of the tool into the production tubing, pumping a cleanout fluid through the production tubing, and thereby forcing the fluid through the perforations and downwards through the central and lower tubular sections into accumulated particulate matter in a lower portion of the production casing, and forcing the fluid and particulate matter upwards in an annulus within the production casing and surrounding the production tubing.
There is also provided in accordance with another aspect o the present invention a cleanout tool for use in an oil well having a production casing, an inner production tubing and a continuous rod extending through the production tubing, the cleanout tool comprising a tubular upper section adapted for connection to a lower end of the continuous rod and having at least one perforation formed therein, a central tubular section to which is attached pack-off means for fluid-tight sealing against the inner surface of the production tubing, and a lower tubular section, each of the tubular sections having an external diameter less than the internal diameter of the production tubing to form an annulus therebetween.
Preferred embodiments of the present inventi.on will now be described in greater detail and will be better ':
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. .
.
1 3 1 1 6~ I
understood from the following description with reference to the accompanying drawings, in which:
Figure 1 is a vertical cross-sectional view of a well casing with a first embodiment of the cleanout too]
in place; and Figure 2 is a cross-sectional view of the central section of a second embodiment of the cleanout tool.
ReEerring to Figure 1, an oil well casing 12 is cemented in place and perforated for oil production, having a-t its lower end adjacent the oil producing zone a slotted liner 13 attached by hanging means 17. The lower end of the liner 13 is w~lded closed to form a bullnose 14. A production tubing 10 is suspended within the casing 12 and liner 13, having an open end 11 typically set approximately three metres above the bullnose 14. An annulus 15 surrounding the production tubing 10 is defined by the outer wall of the production tubing 10 and the inner wall of the casing 12.
During active operation of the well, a pump ~not shown) is suspended by means of a co-rod 9 within the tubing 10, seated by seating nipple 28 at an appropriate height above the open end 11 of the tubing. Particulate matter 18 which enters the liner 13 despite the configuration of the slots (not shown) in the liner will tend to accumulate in the bullnose 14, and will eventually rise to the level of the pump to impede the flow of oil through the pump, often causing the pump to seize and re~uiring a cleanout operation.
For cleanout by the method of the present invention, co-rod 9 is removed from the well and the pump detached therefrom, and a tool 1 is attached in its place by any suitable means, such as screwing or a sucker rod pin, to the lower end of co-rod 9. The co-rod with tool 1 attached is then run into the well. An upper section 2 of the tool is of tubular configuration and has perforations 5 along at least part o~ its surface, which may take the form of longitudinal slots. To the upper section 2 is ,~
, ' : `
`
1 3 1 1 6~ 1 threadedly attached a central section 3. A pack-off cup 6 made of, for e~ample, carboxyenated nitrile rubber, surrounds the central section 3, 50 as to form a seal between the outer surface of tool 1 and the inside wall of production tubing 10. Pack-off cup 6 is seated on -the central section 3 by means of a suitable seating means such as a cup seat 7, mounted above a tubing drift 16.
The central section 3 is also of tubular configuration.
The lower end of the central section 3 is attached by any suitable means such as a collar union 20 to a lower section 4. The lower end 8 of the lower section 4 is open, and the lower section ~ is of tubular conEiguration.
In the embodiment shown in Figure 1, lower section 4 consists of a swedge 31 screw-threaded between collar 20 and a lower collar 29. The lower end of collar 29 is internally threaded for connection to one or more lengths of hollow tubing 30 which together comprise a "stinger", the length of which is chosen so that the distance between the lower end of the stinger and the bottom of tubing drift 16 slightly exceeds the calculated distance from the bullnose to the top of pump seating nipple 28.
The tool is constructed of any suitable material such as high strength steel, and the external diameters of the tubular sections 2, 3 and 4 must be less than the internal diameter oE the production tubing 10 and pump seating nipple 28, sufficient to provide adequate clearance for insertion, removal and flow of cleaning fluid.
When the tool 1 is in place, the cleaning fluid, which is usually water, can be pumped into the upper portion of the production tubing 10, down to a level adjacent to the upper section 2 of the tool 1. The pack-off cup 6 prevents the fluid from passing therebelow, and the fluid is consequently forced into the upper section 2 through the perforations 5 and thence down the inside of the tubular central section 3 to the open-ended stinger 4.
The fluid passes out through the open end 8 of the .
...`'': ." . .
, ~ .
. : . - . , .
-131 16~1 stinger, and thence removes the accumulated particulatematter 18 as it is washed upwards through the annulus 15 between the production tubing 10 and the casing 12, to be removed at the well head. The direction of flow of the cleaning fluid is shown by the arrows A.
Referring now to Figure 2, an alternative embodiment of the central section 3 of the tool 1 is shown, which enables the reverse flow of cleaning fluid for the cleanout operation. For this purpose, it is necessary to impede the flow of cleaning fluid in an upwards direction from the lower portion of the production tubing 10. In the embodiment shown, reverse flow is opposite to the normal flow direction shown in Figure 1, and indicated therein by the arrows A. This reverse flow direction is indicated in Figure 2 by arrows B.
To achieve this reverse flow direction, the tool 1 is additionally provided with a lower pack-off cup 23 in combination with the upper pack-off cup 2i. The two pack-offs 23 and 21 are seated respectively on a lower seat 24 and an upper seat 22, which may be separated by a tubing drift 25.
When reverse flow cleanout is desired, the cleaning fluid is pumped down the annulus 15, to the lower end of the casing 12, to remove accumulated particulate matter 18 from the bullnose 14. The fluid is then forced upwards into the production tubing 10 through the open end 11, or directly into the stinger 4 of the tool 1. The upwards flow of the fluid and particulate matter within the production tubing 10 is restricted by the lower pack-off means 23. All the remaining fluid therefore passesinto and travels upward through the tool 1 to the well head, as indicated by arrow B. As will be appreciated, ; the length of the stinger for this configuration is shortened by the length of pack-off 23 and its associa-ted seat 24.
~ here the well is pressured, the effects of the pressure must be counteracted before the cleanout operation begins. For this purpose, a known snubbing , .
, t31 16~1 stack (not shown) is used, which enables the pressure to be contained, while the use of a known lubricator enables the insertion of the open-ended tool into the pressured well. After the cleanout tool of the invention has been S lubricated into the upper end of the production tubing, through the snubbing stack, the method of use of the tool is as described above for a non-pressured well. Thus, the method of the invention saves the costs tradi-tionally required Eor killing fluids, and overcomes the disadvantages of the traditional use of tubing-snubbing units.
The method of the invention is particularly suitable as part of a preventative maintenance program, in which it can be used for cleanout for example each time a pump is changed. The regular use of the method can avoid damage to the lower portion of the production tubing, by accumulated particulate matter, and damage to the pump.
Where the performance of the cleanout operation is time-consuming, cumbersome or hazardous, there is a tendency for the operator to avoid such regular maintenance, and to perform the cleanout only when the pump has seized, which can result in greater damage to the components. The advantages of the present invention in increased efficiency, reduced time loss, increased safety and economy provide an incentive to implement a beneficial program to maximize those advantages.
The tool 1 for use with the method of the ; invention can be of any suitable size according to the type of well for which it is required. As the pack-off means 6, 21 and 23 are designed to be adapted for use in standard diameters of production tubing lO, the method and the tool 1 are suitable for use in any well having the typical features described above.
Further modification of the method and the tool 1 can be made without departing from the spirit of the invention.
:~
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, ~: ,
Wells producing heavy oil typically comprise an outer production casing, which is cemented into place from the surface to just below the oil producing horizon. This casing is perforated, generally by means of explosive charges, to allow oil to enter. A liner, generally having a welded closed bottom (known as a bullnose), is suspended in the lower portion of the casing, from a liner hanger.
The liner itself has perforations such as slots, to permit the entry of oil, and to restrict the entry of sand or similar matter.
When the liner is in place, a service rig is used to lower an open ended production tubing within the production casing and within the liner, where it is set with the bottom of the tubing about three meters above the bullnosed bottom of the liner. This distance of about three metres facilitates the accumulation and retention of any sand which does enter the liner, rather than permitting it to be drawn into the pump, which is located adjacent to the bottom of the tubing, seated by a seating m~ans.
After the production tubing is set in place, the service rig can be removed, and an operating rig, known as a Co-rod* rig, is moved onto the well, to lower into place a continuous steel rod, at the lower end of which is attached the pump~ The co-rod rig itself is then removed to be replaced by a pump jack for operating the pump to remove the oil.
Despite the design of the liner and the production *Trade-mark tubing, eventually sand and similar matter accumulates to such an extent as to impede the operation of the pump, ultimately causing seizure. At this point, the sand must be cleaned out. The present method involves the re-installation of the co-rod rig to remove the co-rod and the pump from the well, and thereafter, removal of the co-rod rig and installation of the service rig back onto the well to pick up the tubing. For this operation, extra tubing may be added to reach the accumulated matter in the bullnose. Fluid is then pumped into the production tubing, to wash the accumulated matter up to the surface in the annulus between the production tubing and the production casing.
In addition, if the well is under pressure, this pressure must be killed before the extra tubing is added and the cleaning fluid pumped into the well. This is achieved either by the use of known heavy killing fluids, or by the use of a known snubbing unit.
When the accumulated matter has been removed, the extra tubing can be removed, the service rig moved off the well and the co-rod rig is used once again to replace the co-rod and pump. The co-rod rig is in turn replaced by the pump jack for the resumption of the pumping operation.
The present system of cleaning such oil wells suffers from several disadvantages. In particular, there is considerable downtime for production from the well by reason of the time taken to remove the co-rod rig, rod and pump from the vicinity of the well, and to enable the installation of the service rig and extra tubingO During this downtime, pressure problems may arise. In addition, ;there is an inherent increased safety risk involved each time the rigs are exchanged.
; The present invention therefore provides a cleanout method to overcome these disadvantages, by utilizing a simple cleanout tool which requires reduced downtime for the operation of the well, by use only of the -,' '. ~ ;
~ , :
'.
, ~
, 2a 1 31 1 681 co-rod rig, and not necessitating the use of a service rig.
Efficiency and safety are thereby considerably enhanced.
In addition, the tool can include means for enabling the reverse flow of the cleaning fluid, where ~ ~, ~.;: '' ' ::
.
, 3 131 1~81 desirable.
This invention therefore provides a method for particulate matter cleanout for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous rod mounted on a co-rod rig, comprising the following steps, withdrawal of the pumping means to the land surface, connection to the rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within ~he production tubing adjacent the outside of the tool, and a lower tubular section, tha tubular sections having an external diameter less than the internal diameter of the production tubing, insertion of the tool into the production tubing, pumping a cleanout fluid through the production tubing, and thereby forcing the fluid through the perforations and downwards through the central and lower tubular sections into accumulated particulate matter in a lower portion of the production casing, and forcing the fluid and particulate matter upwards in an annulus within the production casing and surrounding the production tubing.
There is also provided in accordance with another aspect o the present invention a cleanout tool for use in an oil well having a production casing, an inner production tubing and a continuous rod extending through the production tubing, the cleanout tool comprising a tubular upper section adapted for connection to a lower end of the continuous rod and having at least one perforation formed therein, a central tubular section to which is attached pack-off means for fluid-tight sealing against the inner surface of the production tubing, and a lower tubular section, each of the tubular sections having an external diameter less than the internal diameter of the production tubing to form an annulus therebetween.
Preferred embodiments of the present inventi.on will now be described in greater detail and will be better ':
: . . ~ ' ............... ',, .~
. .
.
1 3 1 1 6~ I
understood from the following description with reference to the accompanying drawings, in which:
Figure 1 is a vertical cross-sectional view of a well casing with a first embodiment of the cleanout too]
in place; and Figure 2 is a cross-sectional view of the central section of a second embodiment of the cleanout tool.
ReEerring to Figure 1, an oil well casing 12 is cemented in place and perforated for oil production, having a-t its lower end adjacent the oil producing zone a slotted liner 13 attached by hanging means 17. The lower end of the liner 13 is w~lded closed to form a bullnose 14. A production tubing 10 is suspended within the casing 12 and liner 13, having an open end 11 typically set approximately three metres above the bullnose 14. An annulus 15 surrounding the production tubing 10 is defined by the outer wall of the production tubing 10 and the inner wall of the casing 12.
During active operation of the well, a pump ~not shown) is suspended by means of a co-rod 9 within the tubing 10, seated by seating nipple 28 at an appropriate height above the open end 11 of the tubing. Particulate matter 18 which enters the liner 13 despite the configuration of the slots (not shown) in the liner will tend to accumulate in the bullnose 14, and will eventually rise to the level of the pump to impede the flow of oil through the pump, often causing the pump to seize and re~uiring a cleanout operation.
For cleanout by the method of the present invention, co-rod 9 is removed from the well and the pump detached therefrom, and a tool 1 is attached in its place by any suitable means, such as screwing or a sucker rod pin, to the lower end of co-rod 9. The co-rod with tool 1 attached is then run into the well. An upper section 2 of the tool is of tubular configuration and has perforations 5 along at least part o~ its surface, which may take the form of longitudinal slots. To the upper section 2 is ,~
, ' : `
`
1 3 1 1 6~ 1 threadedly attached a central section 3. A pack-off cup 6 made of, for e~ample, carboxyenated nitrile rubber, surrounds the central section 3, 50 as to form a seal between the outer surface of tool 1 and the inside wall of production tubing 10. Pack-off cup 6 is seated on -the central section 3 by means of a suitable seating means such as a cup seat 7, mounted above a tubing drift 16.
The central section 3 is also of tubular configuration.
The lower end of the central section 3 is attached by any suitable means such as a collar union 20 to a lower section 4. The lower end 8 of the lower section 4 is open, and the lower section ~ is of tubular conEiguration.
In the embodiment shown in Figure 1, lower section 4 consists of a swedge 31 screw-threaded between collar 20 and a lower collar 29. The lower end of collar 29 is internally threaded for connection to one or more lengths of hollow tubing 30 which together comprise a "stinger", the length of which is chosen so that the distance between the lower end of the stinger and the bottom of tubing drift 16 slightly exceeds the calculated distance from the bullnose to the top of pump seating nipple 28.
The tool is constructed of any suitable material such as high strength steel, and the external diameters of the tubular sections 2, 3 and 4 must be less than the internal diameter oE the production tubing 10 and pump seating nipple 28, sufficient to provide adequate clearance for insertion, removal and flow of cleaning fluid.
When the tool 1 is in place, the cleaning fluid, which is usually water, can be pumped into the upper portion of the production tubing 10, down to a level adjacent to the upper section 2 of the tool 1. The pack-off cup 6 prevents the fluid from passing therebelow, and the fluid is consequently forced into the upper section 2 through the perforations 5 and thence down the inside of the tubular central section 3 to the open-ended stinger 4.
The fluid passes out through the open end 8 of the .
...`'': ." . .
, ~ .
. : . - . , .
-131 16~1 stinger, and thence removes the accumulated particulatematter 18 as it is washed upwards through the annulus 15 between the production tubing 10 and the casing 12, to be removed at the well head. The direction of flow of the cleaning fluid is shown by the arrows A.
Referring now to Figure 2, an alternative embodiment of the central section 3 of the tool 1 is shown, which enables the reverse flow of cleaning fluid for the cleanout operation. For this purpose, it is necessary to impede the flow of cleaning fluid in an upwards direction from the lower portion of the production tubing 10. In the embodiment shown, reverse flow is opposite to the normal flow direction shown in Figure 1, and indicated therein by the arrows A. This reverse flow direction is indicated in Figure 2 by arrows B.
To achieve this reverse flow direction, the tool 1 is additionally provided with a lower pack-off cup 23 in combination with the upper pack-off cup 2i. The two pack-offs 23 and 21 are seated respectively on a lower seat 24 and an upper seat 22, which may be separated by a tubing drift 25.
When reverse flow cleanout is desired, the cleaning fluid is pumped down the annulus 15, to the lower end of the casing 12, to remove accumulated particulate matter 18 from the bullnose 14. The fluid is then forced upwards into the production tubing 10 through the open end 11, or directly into the stinger 4 of the tool 1. The upwards flow of the fluid and particulate matter within the production tubing 10 is restricted by the lower pack-off means 23. All the remaining fluid therefore passesinto and travels upward through the tool 1 to the well head, as indicated by arrow B. As will be appreciated, ; the length of the stinger for this configuration is shortened by the length of pack-off 23 and its associa-ted seat 24.
~ here the well is pressured, the effects of the pressure must be counteracted before the cleanout operation begins. For this purpose, a known snubbing , .
, t31 16~1 stack (not shown) is used, which enables the pressure to be contained, while the use of a known lubricator enables the insertion of the open-ended tool into the pressured well. After the cleanout tool of the invention has been S lubricated into the upper end of the production tubing, through the snubbing stack, the method of use of the tool is as described above for a non-pressured well. Thus, the method of the invention saves the costs tradi-tionally required Eor killing fluids, and overcomes the disadvantages of the traditional use of tubing-snubbing units.
The method of the invention is particularly suitable as part of a preventative maintenance program, in which it can be used for cleanout for example each time a pump is changed. The regular use of the method can avoid damage to the lower portion of the production tubing, by accumulated particulate matter, and damage to the pump.
Where the performance of the cleanout operation is time-consuming, cumbersome or hazardous, there is a tendency for the operator to avoid such regular maintenance, and to perform the cleanout only when the pump has seized, which can result in greater damage to the components. The advantages of the present invention in increased efficiency, reduced time loss, increased safety and economy provide an incentive to implement a beneficial program to maximize those advantages.
The tool 1 for use with the method of the ; invention can be of any suitable size according to the type of well for which it is required. As the pack-off means 6, 21 and 23 are designed to be adapted for use in standard diameters of production tubing lO, the method and the tool 1 are suitable for use in any well having the typical features described above.
Further modification of the method and the tool 1 can be made without departing from the spirit of the invention.
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Claims (20)
1. A method for particulate matter cleanout for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous rod mounted on a co-rod rig, comprising the following steps:
withdrawal of said pumping means to the land surface;
connection to said rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tubing;
insertion of said tool into said production tubing;
pumping a cleanout fluid through said production tubing, and thereby forcing said fluid through said perforations and downwards through said central and lower tubular sections into accumulated particulate matter in a lower portion of said production casing; and forcing said fluid and particulate matter upwards in an annulus within said production casing and surrounding said production tubing.
withdrawal of said pumping means to the land surface;
connection to said rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tubing;
insertion of said tool into said production tubing;
pumping a cleanout fluid through said production tubing, and thereby forcing said fluid through said perforations and downwards through said central and lower tubular sections into accumulated particulate matter in a lower portion of said production casing; and forcing said fluid and particulate matter upwards in an annulus within said production casing and surrounding said production tubing.
2. The method of claim 1 wherein said particulate matter is accumulated within liner means suspended in said lower portion of said production casing.
3. The method of claim 2 wherein said oil well further includes a seating nipple in said production tubing for said pumping means, said tubing sections having an external diameter less than the internal diameter of said seating nipple.
4. The method of claim 3 wherein the length of said cleanout tool from the bottom of said pack-off means to the lower end of said lower tubular section exceeds the distance from the top of said seating nipple to the bottom of said liner means.
5. A cleanout method as claimed in claim 1 wherein said particulate matter is sand.
6. A cleanout method as claimed in claims 1, 2 or 4 wherein said pack-off means comprise at least one pack-off nipple adapted to cause said cleanout fluid pumped down said production tubing to flow through said perforations, and to otherwise restrict the flow of said fluid between the outside of said cleanout tool and the inside of said production tubing.
7. A method for particulate matter cleanout for an oil well having a production casing, an inner production tubing and pumping means connected to a continuous rod mounted on a co-rod rig, comprising the following steps:
withdrawal of said pumping means to the land surface;
connection to said rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tubing;
pumping a cleanout fluid through said production casing to accumulated particulate matter in a lower portion of said production casing; and forcing said cleanout fluid and particulate matter through the inside of said cleanout tool, through said perforations and thence upwards in an annulus within said production tubing surrounding said continuous rod.
withdrawal of said pumping means to the land surface;
connection to said rod of a cleanout tool of predetermined length and comprising a perforated tubular upper section, a central tubular section to which is attached pack-off means to restrict fluid circulation within said production tubing adjacent the outside of said tool, and a lower tubular section, said tubular sections having an external diameter less than the internal diameter of said production tubing;
pumping a cleanout fluid through said production casing to accumulated particulate matter in a lower portion of said production casing; and forcing said cleanout fluid and particulate matter through the inside of said cleanout tool, through said perforations and thence upwards in an annulus within said production tubing surrounding said continuous rod.
8. The cleanout method of claim 7 wherein said particulate matter accumulates within liner means suspended in said lower portion of said production casing.
9. The method of claims 7 wherein said oil well further includes a seating nipple in said production tubing for said pumping means, said tubing sections having an external diameter less than the internal diameter of said seating nipple.
10. The method of claims 8 wherein said oil well further includes a seating nipple in said production tubing for said pumping means, said tubing sections having an external diameter less than the internal diameter of said seating nipple.
11. The method of claim 9 wherein the length of said cleanout tool from the bottom of said pack-off means to the lower end of said lower tubular section exceeds the distance from the top of said seating nipple to the bottom of said liner means.
12. The method of claim 10 wherein the length of said cleanout tool from the bottom of said pack-off means to the lower end of said lower tubular section exceeds the distance from the top of said seating nipple to the bottom of said liner means.
13. The cleanout method of claim 8 wherein said particulate matter is sand.
14. The cleanout method of claim 7 or 8 wherein said pack-off means comprise at least one pack-off nipple adapted to seal against the inner surface of said production tubing in fluid-tight relationship and to divert the flow of said cleanout fluid and particulate matter through the inside of said cleanout tool.
15. The cleanout method of claim 11 or 12 wherein said pack-off means comprise at least one pack-off nipple adapted to seal against the inner surface of said production tubing in fluid-tight relationship and to divert the flow of said cleanout fluid and particulate matter through the inside of said cleanout tool.
16. A cleanout tool for use in an oil well having a production casing, an inner production tubing and a continuous rod extending through said production tubing, said cleanout tool comprising a tubular upper section adapted for connection to a lower end of said continuous rod and having at least one perforation formed therein;
a central tubular section to which is attached pack-off means for fluid-tight sealing against the inner surface of said production tubing; and a lower tubular section, each of said tubular sections having an external diameter less than the internal diameter of said production tubing to form an annulus therebetween.
a central tubular section to which is attached pack-off means for fluid-tight sealing against the inner surface of said production tubing; and a lower tubular section, each of said tubular sections having an external diameter less than the internal diameter of said production tubing to form an annulus therebetween.
17. The cleanout tool of claim 16 wherein said pack-off means comprise at least one pack-off nipple adapted to divert the flow of cleanout fluid pumped down through said production tubing through said at least one perforation in said central tubular section.
18. The cleanout tool of claim 16 wherein said pack-off means include at least one pack-off nipple adapted to divert the flow of cleanout fluid pumped down through the annulus between said production tubing and said production casing through said cleanout tool and into the interior of said production tubing.
19. The cleanout tool of claims 16, 17 or 18 wherein a tubing drift is attached to said central tubular section adjacent said pack-off means thereon.
20. The cleanout tool of claims 16, 17 or 18 wherein said at least one perforation in said tubular upper section is a longitudinal slot.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000564133A CA1311681C (en) | 1988-04-14 | 1988-04-14 | Sand tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000564133A CA1311681C (en) | 1988-04-14 | 1988-04-14 | Sand tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1311681C true CA1311681C (en) | 1992-12-22 |
Family
ID=4137837
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000564133A Expired CA1311681C (en) | 1988-04-14 | 1988-04-14 | Sand tool |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1311681C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103277059A (en) * | 2013-05-30 | 2013-09-04 | 中国石油天然气股份有限公司 | Negative pressure combined sand washing and forced sand discharging device |
| RU199514U1 (en) * | 2020-06-17 | 2020-09-04 | Общество с ограниченной ответственностью Научно-производственная фирма "Пакер" | Well flushing device |
-
1988
- 1988-04-14 CA CA000564133A patent/CA1311681C/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103277059A (en) * | 2013-05-30 | 2013-09-04 | 中国石油天然气股份有限公司 | Negative pressure combined sand washing and forced sand discharging device |
| CN103277059B (en) * | 2013-05-30 | 2015-11-18 | 中国石油天然气股份有限公司 | Negative pressure combined sand washing and forced sand discharging device |
| RU199514U1 (en) * | 2020-06-17 | 2020-09-04 | Общество с ограниченной ответственностью Научно-производственная фирма "Пакер" | Well flushing device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |