CA2181668A1 - Method of abandonment of an oil well - Google Patents
Method of abandonment of an oil wellInfo
- Publication number
- CA2181668A1 CA2181668A1 CA002181668A CA2181668A CA2181668A1 CA 2181668 A1 CA2181668 A1 CA 2181668A1 CA 002181668 A CA002181668 A CA 002181668A CA 2181668 A CA2181668 A CA 2181668A CA 2181668 A1 CA2181668 A1 CA 2181668A1
- Authority
- CA
- Canada
- Prior art keywords
- cutting head
- outer casing
- cutting
- upper portion
- severed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000003129 oil well Substances 0.000 title claims abstract description 20
- 238000005520 cutting process Methods 0.000 claims abstract description 102
- 239000007789 gas Substances 0.000 description 3
- 244000228957 Ferula foetida Species 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 241001137251 Corvidae Species 0.000 description 1
- 101100536883 Legionella pneumophila subsp. pneumophila (strain Philadelphia 1 / ATCC 33152 / DSM 7513) thi5 gene Proteins 0.000 description 1
- 101100240664 Schizosaccharomyces pombe (strain 972 / ATCC 24843) nmt1 gene Proteins 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 235000015108 pies Nutrition 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
- E21B29/002—Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe
- E21B29/005—Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe with a radially-expansible cutter rotating inside the pipe, e.g. for cutting an annular window
-
- 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
- E21B10/00—Drill bits
- E21B10/26—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers
- E21B10/32—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers with expansible cutting tools
-
- 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
- E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
-
- 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
- E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
- E21B29/002—Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe
-
- 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
- E21B31/00—Fishing for or freeing objects in boreholes or wells
- E21B31/12—Grappling tools, e.g. tongs or grabs
- E21B31/16—Grappling tools, e.g. tongs or grabs combined with cutting or destroying means
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)
- Marine Sciences & Fisheries (AREA)
- Mechanical Engineering (AREA)
- Earth Drilling (AREA)
Abstract
A method of abandonment of an oil well. Firstly, providing a cutting tool including a cutting head with radially extendable blades, a rotary drive unit capable of rotating the cutting head, and a connecting shaft extending from the rotary drive unit to the cutting head. Secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface. Thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the inner casing has been severed. Fourthly, withdrawing the cutting head and pulling out of the outer casing the severed upper portion of the inner casing. Fifthly, setting a plug in the outer casing with a plug setting tool to provide pressure containment. The plug is set below a desired cutting depth for severing the outer casing. Sixthly, reinserting the connecting shaft into the outer casing until the cutting head is positioned at the desired cutting depth for severing the outer casing. Seventhly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the outer casing has been severed. Eighthly, removing the severed upper portion of the outer casing and burying the outer casing.
Description
2181~8 TITLE OF THE lnv~
a method of AhAr~ of an oil well NAME OF lhv~n:
Anthony Erwin FIEL~ OF THE l~v~_ The present invention relates to a method of AhAn~
of an oil well.
P~ OF THE INVENTION
Every oil well has an outer casing and, an inner casing which is concentrically ~;cpQsQd within the outer casing.
When the oil well is to be ~hAn~nn~d, the outer casing and the inner casing must be cut off below the surface of the ground in order to permit the oil well to be buried. A trench is first excavated around the outer casing using a backhoe in preparation for cutting. It is generally considered to be critical that the inner casing be cut first, as the inner casing extends for thmlcAn~c of meters below the surface of the ground with the weight of the inner casing supported by the outer casing. The cumulative weight of the thmlcAn~ of meters of pipe results in the inner casing being placed in tension.
This tension stretches the inner casing in a fashion that is ~nAlQgQIlc to an elastic. When the inner casing is cut this built up energy is released. In order to provide access to the inner casing for the purpose of cutting it first, windows are cut with a cutting torch through the outer casing. The inner casing is then cut by inserting the cutting torch through the windows. Once the inner casing has been cut and removed, the outer casing is cut and removed. Cement is then mixed and 2181~8 poured down the outer casing and a cap is welded onto the outer casing. One can never be absolutely certain as to the amount of yl~s~ule cnntA; provided through this method, as it depends to a large extent on the quality of the weld. Once the cap is in place, the outer casing is buried.
This method of IhAr~ ~ has a number of disadvantages.
The cutting of windows in the outer casing adversely effects its structural integrity and, as a result, it is not unusual for the outer casings to collapae. When a collapse of the outer casing occurs the welder handling the cutting torch is placed in grave danger. A snffi~i~nt number of welders have been seriously injured that it is standard practise to support the outer casing with lifting equipment during the AhAn~ ~
pIoceduL~s. This safety measure is not always effective, as sometimes the lifting equipment is unable to support the outer casing in the face of the forces transferred by the inner casing and, as a result, the lifting equipment is pulled over.
SIJMMARY OF T~IE lO~vr~r~ 1l What is required is a safer method of AhAn~ni ng an oil well.
According to the present invention there is provided a method of ~hAn~ of an oil well. The method ;n~ A~ the following steps. Firstly, providing a cutting tool in~ln~ing a cutting head with radially extendable blade3, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially ext~n~Ahle blades of the cutting head. Secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth ~ 21816~8 for severing the inner casing. Thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and c~n~imling to rotate the cutting head until an upper portion of the inner casing has been severed. Eourthly, withdrawing the cutting head and pulling out of the outer casing the severed upper portion of the inner casing. Fifthly, setting a plug in the outer casing with a plug setting tool to provide ~IegDuLe cont~i L. The plug is set below a desired cutting depth for severing the outer casing. Sixthly, reinserting the connecting shaft into the outer casing until the cutting head is positioned at the desired cutting depth for severing the outer casing.
Seventhly, rotating the cutting head with the rotary drive unit while ~Yt~n~ing the radially PYt~n~hle blade8 on the cutting head and continuing to rotate the cutting head until an upper portion of the outer casing has been 3evered. Eighthly, removing the severed upper portion of the outer casing and burying the outer casing.
BRIEF ~_5~Kl~ lON OF THE ~xAh These and other features of the invention will become more apparent from the following description in which reference is made to the App~n~ drawings, wherein:
FIGURE 1 is a side elevation view, in section, of a cutting tool being used to sever an inner casing in accordance with the t~A~h; ngs of the present invention.
FIGURE 2 is a side elevation view, in section, of a plug setting tool being used to set a plug in an outer casing in accordance with the t~A~hing~ of the present invention.
FIGURE 3 is a side elevation view, in section, of a cutting tool being used to 3ever an outer casing in accordance with the t~A~hing~ of the present invention.
DF~TT~n ~S~l~ OF THE l-~rr 21816~8 The preferred method of AhAna, L will now be described with reference to FIGURES 1 through 3.
The method, as will hereinafter be ~a~esrr;hed, u3es ~ifi~d ver8iong of two tool3 that are commercially available.
Referring to FIGURES 1 and 3, there is illustrated a cutting tool 12. Cutting tool 12 includes a cutting head 14 with radially extendable blades 16. A rotary drive unit 18 is provided which is capable of rotating cutting head 14. A
tubular connecting shaft 20 extends from rotary drive unit 18 to cutting head 14. A pump 22 is provided with an hydraulic ~ A1 cord 24 that extends down to radially extendable blades 16. Hydraulic fluid provided by pump 22 through ;l;rAl cord 24 serveg as means for selectively extending radially ext~n~aAhle blades 16 of cutting head 14 during cutting operations. Cutting tools similar to cutting tool 12 are manufactured by both Baker-Hughes Corporation and Weatherford-~nterra Corporation. However, the cutting tools tho3e c~ i~8 manufacture are intended to be placed downhole and activated by pumping drilling fluid through them. In order to make their cutting tool suitable for the intended use, they had to be a; f; e~a~ to work on surface with a rotary drive unit, preferably hydraulic. Referring to FIGURE 2 there is illustrated a plug setting tool 26 that is used to set a plug 28. Plug setting tools like plug setting tool 26 and plugs like plug 28 are manufactured by Baker-Hughes Corporation. The plug setting tools manufactured by Baker-Hughes are intended to be triggered deep downhole with explosive charges. In order to make the plug setting tools suitable for the ;nt~n~a~d u3e they had to be l;f; ~ to be triggered with hydraulic pIes~uL~. The plugs, however, can be used in A~c~r~alAn~e with the t~Arh; ng~ of the present method without 'i~i~ation.
The method in~ln~ the following steps. Firstly, providing a cutting tool, equivalent to cutting tool 12, as d~r;h~tal above. Secondly, with reference to FIGURE 1, lowering connecting shaft 20 into an inner casing 30 which is 21816~8 concentrically disposed within an outer casing 32 of an oil well, generally indicated by reference numeral lO. In thi3 manner, cutting head 14 i8 positioned below a ground surface 34 at a desired cutting depth for severing inner casing 30.
The desired cutting depth is indicated by broken line 36. It is equal to or greater than the depth that inner ca~ing 30 was previously severed using the prior art methods. In preparation for use it is preferred that cutting tool 12 be bolted to a flange 38 on outer casing 32. It i8 also preferred that cutting tool 12 be equipped with s~hili~i ng outrigger legs 39.
It is finally preferred that a centralizer/stabilizer 40 be positioned along connecting shaft 20. Thirdly, rotating cutting head 14 with rotary drive unit 18 while extending radially extendable blades 16 on cutting head 14. Cutting head 14 i5 rotated at low r.p.m. to bring blades 16 310wly out against inner casing 30. Blades 16 centralize and 3tart cutting. Cutking head 14 is rotated until an upper portion 42 of inner casing 30 has been severed. Fourthly, withdrawing cutting head 14 and pulling out of outer casing 32 severed upper portion 42 of inner casing 30. Fifthly, with reference to FIGUR3 2, setting plug 28 in outer casing 32 with plug setting tool 26. The setting of plug 28 provides pLes~uLe containment. Plugs, such as plug 28, are commercially available in versions rated for ~Ie~u-~s of up to 10,000 p.~.i. and are available with re-enterable valve3. Such valves make it easier to bring oil well lO back into active service at a later date, if desired. Plug 28 is set below a desired cutting depth for severing the outer casing, indicated by broken line 44. Sixthly, with reference to FIGURE 3, reinserting connecting shaft 20 into outer ca~ing 32 until cutting head 14 is positioned at desired cutting depth 44 for severing outer casing 32. Seventhly, rotating cutting head 14 with rotary drive unit 18 while extending radially extendable blades 16 on cutting head 14. Cutting head 14 is rotated until an upper portion 46 of outer casing 32 has been severed.
~ighthly, removing severed upper portion 46 of outer casing 32 and burying outer casing 32.
,, , . , ,, _ _ _ _ _ _ _ _ _ ,,, ~ 21816~8 Although the method ~P~rih~d above i3 preferred, there are times when it is ; ~~~ihle to remove severed upper portion 42 of inner casing 30. Is such a case, cutting head 14 is used to sever both inner casing 30 and outer casing 32 in the same step. Plug 28 is then set after both severed upper portion 42 of inner casing 30 and severed upper portion 46 of outer casing 32 have been removed.
As with the prior art method in which a cutting torch is used, oil well 10 should be checked for the presence of explosive or combustible gases prior to uge of the ~li .
The above ~ rihpd method is safer than the prior art method, even if gas should be encountered in spite of precautions. With the prior art method, ~Yplo~i ~n~ and fires have been ignited by the open flame of the cutting torch, due to the presence of gas. The present method is safer for a number of reasons.
There is no need to excavate, 80 outer casing 32 will have the benefit of support from the ~uLL~ullding ground. Cutting tool 12 can be operated at a distance, 80 personnel can be a safe distance away when inner casing 30 is cut. The proto-type has hydraulic cables that allows activation from 10 meters away.
It will be apparent to one skilled in the art that the method ~es~r;h~d above, is not only safer but facilitates the return of oil well 10 to active service at a later date. With the prior art method of ~hAr-l L, a valve has to be welded onto the cap. The cap is then drilled through, using the valve as a means of containing pressure, a process referred to as "hot tapping~-. This hot tapping is acknowledged as being a dangerouY procedure as, the prior art method of AhAn~ L
leaves the amount of presgure contAi L uncertain. In contrast, with the present method a plug can be selected that provides a known pressure conf A i L. This pressure contAi can be carefully selected to be 2000 to 3000 p.s.i.
greater than the highest recorded pressure for oil well 10.
The pressure can be tested prior to reorPning the well. If there is no intention of ever r~tllrni ng the well to active ~ 2181S68 service, cement can be poured on top of plug 28 after installation. It will finally be apparent to one skilled in the art that ~; f; rations may be made to the method without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
a method of AhAr~ of an oil well NAME OF lhv~n:
Anthony Erwin FIEL~ OF THE l~v~_ The present invention relates to a method of AhAn~
of an oil well.
P~ OF THE INVENTION
Every oil well has an outer casing and, an inner casing which is concentrically ~;cpQsQd within the outer casing.
When the oil well is to be ~hAn~nn~d, the outer casing and the inner casing must be cut off below the surface of the ground in order to permit the oil well to be buried. A trench is first excavated around the outer casing using a backhoe in preparation for cutting. It is generally considered to be critical that the inner casing be cut first, as the inner casing extends for thmlcAn~c of meters below the surface of the ground with the weight of the inner casing supported by the outer casing. The cumulative weight of the thmlcAn~ of meters of pipe results in the inner casing being placed in tension.
This tension stretches the inner casing in a fashion that is ~nAlQgQIlc to an elastic. When the inner casing is cut this built up energy is released. In order to provide access to the inner casing for the purpose of cutting it first, windows are cut with a cutting torch through the outer casing. The inner casing is then cut by inserting the cutting torch through the windows. Once the inner casing has been cut and removed, the outer casing is cut and removed. Cement is then mixed and 2181~8 poured down the outer casing and a cap is welded onto the outer casing. One can never be absolutely certain as to the amount of yl~s~ule cnntA; provided through this method, as it depends to a large extent on the quality of the weld. Once the cap is in place, the outer casing is buried.
This method of IhAr~ ~ has a number of disadvantages.
The cutting of windows in the outer casing adversely effects its structural integrity and, as a result, it is not unusual for the outer casings to collapae. When a collapse of the outer casing occurs the welder handling the cutting torch is placed in grave danger. A snffi~i~nt number of welders have been seriously injured that it is standard practise to support the outer casing with lifting equipment during the AhAn~ ~
pIoceduL~s. This safety measure is not always effective, as sometimes the lifting equipment is unable to support the outer casing in the face of the forces transferred by the inner casing and, as a result, the lifting equipment is pulled over.
SIJMMARY OF T~IE lO~vr~r~ 1l What is required is a safer method of AhAn~ni ng an oil well.
According to the present invention there is provided a method of ~hAn~ of an oil well. The method ;n~ A~ the following steps. Firstly, providing a cutting tool in~ln~ing a cutting head with radially extendable blade3, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially ext~n~Ahle blades of the cutting head. Secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth ~ 21816~8 for severing the inner casing. Thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and c~n~imling to rotate the cutting head until an upper portion of the inner casing has been severed. Eourthly, withdrawing the cutting head and pulling out of the outer casing the severed upper portion of the inner casing. Fifthly, setting a plug in the outer casing with a plug setting tool to provide ~IegDuLe cont~i L. The plug is set below a desired cutting depth for severing the outer casing. Sixthly, reinserting the connecting shaft into the outer casing until the cutting head is positioned at the desired cutting depth for severing the outer casing.
Seventhly, rotating the cutting head with the rotary drive unit while ~Yt~n~ing the radially PYt~n~hle blade8 on the cutting head and continuing to rotate the cutting head until an upper portion of the outer casing has been 3evered. Eighthly, removing the severed upper portion of the outer casing and burying the outer casing.
BRIEF ~_5~Kl~ lON OF THE ~xAh These and other features of the invention will become more apparent from the following description in which reference is made to the App~n~ drawings, wherein:
FIGURE 1 is a side elevation view, in section, of a cutting tool being used to sever an inner casing in accordance with the t~A~h; ngs of the present invention.
FIGURE 2 is a side elevation view, in section, of a plug setting tool being used to set a plug in an outer casing in accordance with the t~A~hing~ of the present invention.
FIGURE 3 is a side elevation view, in section, of a cutting tool being used to 3ever an outer casing in accordance with the t~A~hing~ of the present invention.
DF~TT~n ~S~l~ OF THE l-~rr 21816~8 The preferred method of AhAna, L will now be described with reference to FIGURES 1 through 3.
The method, as will hereinafter be ~a~esrr;hed, u3es ~ifi~d ver8iong of two tool3 that are commercially available.
Referring to FIGURES 1 and 3, there is illustrated a cutting tool 12. Cutting tool 12 includes a cutting head 14 with radially extendable blades 16. A rotary drive unit 18 is provided which is capable of rotating cutting head 14. A
tubular connecting shaft 20 extends from rotary drive unit 18 to cutting head 14. A pump 22 is provided with an hydraulic ~ A1 cord 24 that extends down to radially extendable blades 16. Hydraulic fluid provided by pump 22 through ;l;rAl cord 24 serveg as means for selectively extending radially ext~n~aAhle blades 16 of cutting head 14 during cutting operations. Cutting tools similar to cutting tool 12 are manufactured by both Baker-Hughes Corporation and Weatherford-~nterra Corporation. However, the cutting tools tho3e c~ i~8 manufacture are intended to be placed downhole and activated by pumping drilling fluid through them. In order to make their cutting tool suitable for the intended use, they had to be a; f; e~a~ to work on surface with a rotary drive unit, preferably hydraulic. Referring to FIGURE 2 there is illustrated a plug setting tool 26 that is used to set a plug 28. Plug setting tools like plug setting tool 26 and plugs like plug 28 are manufactured by Baker-Hughes Corporation. The plug setting tools manufactured by Baker-Hughes are intended to be triggered deep downhole with explosive charges. In order to make the plug setting tools suitable for the ;nt~n~a~d u3e they had to be l;f; ~ to be triggered with hydraulic pIes~uL~. The plugs, however, can be used in A~c~r~alAn~e with the t~Arh; ng~ of the present method without 'i~i~ation.
The method in~ln~ the following steps. Firstly, providing a cutting tool, equivalent to cutting tool 12, as d~r;h~tal above. Secondly, with reference to FIGURE 1, lowering connecting shaft 20 into an inner casing 30 which is 21816~8 concentrically disposed within an outer casing 32 of an oil well, generally indicated by reference numeral lO. In thi3 manner, cutting head 14 i8 positioned below a ground surface 34 at a desired cutting depth for severing inner casing 30.
The desired cutting depth is indicated by broken line 36. It is equal to or greater than the depth that inner ca~ing 30 was previously severed using the prior art methods. In preparation for use it is preferred that cutting tool 12 be bolted to a flange 38 on outer casing 32. It i8 also preferred that cutting tool 12 be equipped with s~hili~i ng outrigger legs 39.
It is finally preferred that a centralizer/stabilizer 40 be positioned along connecting shaft 20. Thirdly, rotating cutting head 14 with rotary drive unit 18 while extending radially extendable blades 16 on cutting head 14. Cutting head 14 i5 rotated at low r.p.m. to bring blades 16 310wly out against inner casing 30. Blades 16 centralize and 3tart cutting. Cutking head 14 is rotated until an upper portion 42 of inner casing 30 has been severed. Fourthly, withdrawing cutting head 14 and pulling out of outer casing 32 severed upper portion 42 of inner casing 30. Fifthly, with reference to FIGUR3 2, setting plug 28 in outer casing 32 with plug setting tool 26. The setting of plug 28 provides pLes~uLe containment. Plugs, such as plug 28, are commercially available in versions rated for ~Ie~u-~s of up to 10,000 p.~.i. and are available with re-enterable valve3. Such valves make it easier to bring oil well lO back into active service at a later date, if desired. Plug 28 is set below a desired cutting depth for severing the outer casing, indicated by broken line 44. Sixthly, with reference to FIGURE 3, reinserting connecting shaft 20 into outer ca~ing 32 until cutting head 14 is positioned at desired cutting depth 44 for severing outer casing 32. Seventhly, rotating cutting head 14 with rotary drive unit 18 while extending radially extendable blades 16 on cutting head 14. Cutting head 14 is rotated until an upper portion 46 of outer casing 32 has been severed.
~ighthly, removing severed upper portion 46 of outer casing 32 and burying outer casing 32.
,, , . , ,, _ _ _ _ _ _ _ _ _ ,,, ~ 21816~8 Although the method ~P~rih~d above i3 preferred, there are times when it is ; ~~~ihle to remove severed upper portion 42 of inner casing 30. Is such a case, cutting head 14 is used to sever both inner casing 30 and outer casing 32 in the same step. Plug 28 is then set after both severed upper portion 42 of inner casing 30 and severed upper portion 46 of outer casing 32 have been removed.
As with the prior art method in which a cutting torch is used, oil well 10 should be checked for the presence of explosive or combustible gases prior to uge of the ~li .
The above ~ rihpd method is safer than the prior art method, even if gas should be encountered in spite of precautions. With the prior art method, ~Yplo~i ~n~ and fires have been ignited by the open flame of the cutting torch, due to the presence of gas. The present method is safer for a number of reasons.
There is no need to excavate, 80 outer casing 32 will have the benefit of support from the ~uLL~ullding ground. Cutting tool 12 can be operated at a distance, 80 personnel can be a safe distance away when inner casing 30 is cut. The proto-type has hydraulic cables that allows activation from 10 meters away.
It will be apparent to one skilled in the art that the method ~es~r;h~d above, is not only safer but facilitates the return of oil well 10 to active service at a later date. With the prior art method of ~hAr-l L, a valve has to be welded onto the cap. The cap is then drilled through, using the valve as a means of containing pressure, a process referred to as "hot tapping~-. This hot tapping is acknowledged as being a dangerouY procedure as, the prior art method of AhAn~ L
leaves the amount of presgure contAi L uncertain. In contrast, with the present method a plug can be selected that provides a known pressure conf A i L. This pressure contAi can be carefully selected to be 2000 to 3000 p.s.i.
greater than the highest recorded pressure for oil well 10.
The pressure can be tested prior to reorPning the well. If there is no intention of ever r~tllrni ng the well to active ~ 2181S68 service, cement can be poured on top of plug 28 after installation. It will finally be apparent to one skilled in the art that ~; f; rations may be made to the method without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
Claims (2)
1. A method of abandonment of an oil well, comprising the steps of:
firstly, providing a cutting tool including a cutting head with radially extendable blades, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially extendable blades of the cutting head;
secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth for severing the inner casing;
thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the inner casing has been severed;
fourthly, withdrawing the cutting head and pulling out of the outer casing the severed upper portion of the inner casing;
fifthly, setting a plug in the outer casing with a plug setting tool to provide pressure containment, the plug being set below a desired cutting depth for severing the outer casing;
sixthly, reinserting the connecting shaft into the outer casing until the cutting head is positioned at the desired cutting depth for severing the outer casing;
seventhly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the outer casing has been severed; and eighthly, removing the severed upper portion of the outer casing and burying the outer casing.
firstly, providing a cutting tool including a cutting head with radially extendable blades, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially extendable blades of the cutting head;
secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth for severing the inner casing;
thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the inner casing has been severed;
fourthly, withdrawing the cutting head and pulling out of the outer casing the severed upper portion of the inner casing;
fifthly, setting a plug in the outer casing with a plug setting tool to provide pressure containment, the plug being set below a desired cutting depth for severing the outer casing;
sixthly, reinserting the connecting shaft into the outer casing until the cutting head is positioned at the desired cutting depth for severing the outer casing;
seventhly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the outer casing has been severed; and eighthly, removing the severed upper portion of the outer casing and burying the outer casing.
2. A method of abandonment of an oil well, comprising the steps of:
firstly, providing a cutting tool including a cutting head with radially extendable blades, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially extendable blades of the cutting head;
secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth for severing the inner casing and the outer casing;
thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the inner casing has been severed, and continuing to rotate the cutting head until an upper portion of the outer casing has been severed;
fourthly, withdrawing the cutting head and removing the severed upper portion of the inner casing and the severed upper portion of the outer casing ;
fifthly, setting a plug in the outer casing with a plug setting tool to provide pressure containment; and sixthly, burying the outer casing.
firstly, providing a cutting tool including a cutting head with radially extendable blades, a rotary drive unit capable of rotating the cutting head, a connecting shaft extending from the rotary drive unit to the cutting head, and means for selectively extending the radially extendable blades of the cutting head;
secondly, lowering the connecting shaft into an inner casing which is concentrically disposed within an outer casing of the oil well until the cutting head is positioned below a ground surface at a desired cutting depth for severing the inner casing and the outer casing;
thirdly, rotating the cutting head with the rotary drive unit while extending the radially extendable blades on the cutting head and continuing to rotate the cutting head until an upper portion of the inner casing has been severed, and continuing to rotate the cutting head until an upper portion of the outer casing has been severed;
fourthly, withdrawing the cutting head and removing the severed upper portion of the inner casing and the severed upper portion of the outer casing ;
fifthly, setting a plug in the outer casing with a plug setting tool to provide pressure containment; and sixthly, burying the outer casing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002181668A CA2181668A1 (en) | 1996-07-19 | 1996-07-19 | Method of abandonment of an oil well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002181668A CA2181668A1 (en) | 1996-07-19 | 1996-07-19 | Method of abandonment of an oil well |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2181668A1 true CA2181668A1 (en) | 1998-01-20 |
Family
ID=4158637
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002181668A Abandoned CA2181668A1 (en) | 1996-07-19 | 1996-07-19 | Method of abandonment of an oil well |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2181668A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10989017B2 (en) | 2015-04-01 | 2021-04-27 | Ardyne Holdings Limited | Method of abandoning a well |
-
1996
- 1996-07-19 CA CA002181668A patent/CA2181668A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10989017B2 (en) | 2015-04-01 | 2021-04-27 | Ardyne Holdings Limited | Method of abandoning a well |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |