Patent Application
20220170337
The invention relates to a method and a system for pulling tubulars from a subterranean well.
The present invention relates to a method and a system for pulling tubulars from a subterranean well.
A hydrocarbon well undergoes completion once it has been drilled. Casing is tubing that is set inside the drilled well to protect and support the wellstream. In addition to providing stabilization and keeping the sides of the well from caving in on themselves, casing protects the wellstream from outside contaminants. Casing a well involves running steel pipe down the inside of a recently drilled well. The small space between the casing and the untreated sides of the well is filled with cement to permanently set the casing in place.
The casing is fabricated in sections, or joints, that are usually about 40 feet long (12 m) and screwed together to form longer lengths of casing, called casing strings. A well is drilled in stages to a certain depth, cased and cemented, and then drilled to a deeper depth, cased and cemented again, and so on. Each time the well is cased, a smaller diameter casing is used.
The widest type of casing is called conductor pipe, and it usually is about 30 to 42 inches in diameter for offshore wells and 16 inches in diameter for onshore wells. The next size in casing string is the surface casing, which can run several thousand feet in length. The last type of casing string that is run into the well, and therefore the smallest in diameter, is the production string or oil string. The production string is run directly into the producing reservoir.
When pulling a completion or abandoning a well the tubulars can be difficult to pull free due to solids that have settled in the annulus between the tubular to be pulled and the casing/tubular on the outside. With fine solids settled in the annulus there will be a relatively low permeability and pulling the tubular will result in a pressure drop along the surface of the tubular. The pressure drop will significantly increase the force needed to pull the tubing and added to the friction between the tubular and the settled solids the required pulling force might exceed the yield strength of the tubing or the pulling capability of the work string. The settled solids can origin from solids suspended in the mud or intentionally placed there.
WO 2013/133718 A1 teaches a method for removing casing from a well. The method includes setting a first sealing element into fluid-sealing engagement with the inside of the casing, lowering a flow-through string into the well, a cutting tool and a second, reversibly expandable sealing element being connected to the string, forming perforations into the casing by means of said cutting tool, expanding the second, expandable sealing element into fluid-sealing engagement with the inside of the casing, passing a pressurized fluid through the string and into the annulus via the perforations, so that the viscous and/or solid mass is displaced up the annulus, cutting the casing around its entire circumference; and pulling a length of the casing up from the well. The method utilizes expandable sealing element and passing a fluid at high pressure through the string into the annulus via perforations, so that the solids mass is displaced out of the annulus.
WO 2013/115655 A1 relates to a method and an apparatus for retrieving a tubing from a well at least partly filled with a liquid. The tubing having a first end portion and a second end portion. The method including the steps of (a) running a retrieval apparatus using a connecting means from a surface and into the well, the retrieval apparatus including: an engagement means for engaging the tubing; a sealing means for sealing a portion of the bore of the tubing; injection means for injecting a low density fluid into the tubing, (b) connecting the engagement means to a portion of the tubing; (c) activating the sealing means to close liquid communication in the bore of the tubing between the first end portion and the second end portion; (d) replacing at least a portion of a volume of liquid defined by the sealing means, the tubing and the second end portion of the tubing by a low density fluid introduced in said volume by the injection means; and (e) retrieving the tubing out of the well using the connecting means.
Pulling tubing in this scenario can result in recovery of only short sections of tubing and consequently many and time-consuming runs. There is therefore a need for an effective method for pulling tubulars from a subterranean well. It is an objective of the present invention to achieve this and to provide further advantages over the prior art. At least one of these aims is achieved by the device indicated in the enclosed independent claims. Other favorable or possible embodiments are indicated in the dependent claims.
WO 2015/105427 discloses a method for pulling casing pipes/liner in a petroleum well, comprising the steps of: a) perforating an actual section of said casing pipe in said well by means of a perforating gun, and then b) washing, by means of a washing tool in at least one casing pipe annulus outside the perforated section of said casing pipe for removing debris material, particles, cement or other bonding substances which otherwise hold said casing pipe section stuck, c) cutting, by means of a cutting tool said casing pipe within or below the perforated section for releasing it from the deeper residing, remaining portion of said casing pipe in said well, d) pulling said released, washed-out section of said casing pipe out of said well.
Using a wash tool as described above will necessitate enough space below the lowermost perforation to accommodate the perforating guns or any other components located below the wash tool in order to access the perforated section with the wash tool. An internal restriction below the area of interest might therefor limit the length of the perforation that can be achieved. Furthermore the washing by circulating fluids are often time consuming.
It is provided a method for pulling tubulars (2) out of a subterranean well (100), the method comprising the steps of:
In one embodiment, the work string further comprising a tubular cutting tool configured for circumferentially cutting the tubular. In one embodiment, after step ii), forming the tubular a cut with the tubular cutting tool.
In one embodiment, the pulling tool can be in the form of a down hole jacking tool.
In one embodiment, the work string further comprising a surge tool.
In one embodiment, the surge tool comprising a fluid chamber.
In one embodiment, the fluid chamber has an internal pressure lower than the pressure in the tubular. In one embodiment, the fluid chamber comprising gas.
In one embodiment, after step iii), activating the surge tool.
In one embodiment, the inner tubular is a production tubing. In one embodiment, the outer tubular is a casing.
In one embodiment, before step i), installing a seal a location below the tubular that is removed.
There is also provided a system for pulling tubulars in a subterranean well, the system comprising a perforating tool for perforating the tubular; a tubular pulling tool configured for pulling the tubular out of the subterranean, a cutting tool configured for forming a cut of the tubular, a surge tool comprising a fluid chamber with an internal pressure that is lower than the well pressure and the pressure in an annulus defined between the tubular and an outer tubular, wherein the perforating tool and the tubular pulling tool, the cutting tool and the surge tool are attached to a work string characterized in that the system not comprising a fluid circulation arrangement from the surface.
In one embodiment, the perforating tool comprising one or more perforating guns.
In one embodiment, the perforating tool is configured for forming the cut on the tubular.
In one embodiment, the inner tubular is a production tubing. In one embodiment, the outer tubular is a casing.
In an aspect, a method of pulling a tubular out of a subterranean well was disclosed including the steps of:
There are a number of embodiments of this aspect. In an embodiment, the work string further includes a tubular cutting tool configured for forming the cut on the tubular. In an embodiment the perforating tool is configured for forming the cut on the tubular. In an embodiment the pulling tool is a down hole jacking tool. In an embodiment the work string further includes a surge tool. In an embodiment the surge tool includes a fluid chamber. In an embodiment the fluid chamber has an internal pressure lower than the pressure in the tubular. In an embodiment the fluid chamber includes a gas. In an embodiment in which after step iv), the step of activating the surge tool is performed. In an embodiment, before step i), the step of installing a seal area below the tubular that is removed is performed
In another aspect, a system is disclosed to pull a tubular out of a subterranean well, including a work string including:
In an embodiment of the aspect, the means to create a weakness in the tubular is a cutting tool or an arrangement on a portion of the perforation tool. An embodiment of the aspect includes a surge tool includes a fluid chamber with an internal pressure that is lower than the well pressure and the pressure in the annulus. In an embodiment of the aspect, the perforating tool includes one or more perforating guns. In an embodiment of the aspect, the cut is formed before or during the activation of the perforating tool
These and other possible alternative or advantageous embodiments of the invention will become clear from the following detailed description of an embodiment, given as non-limiting examples, with reference to the attached schematic drawings, wherein:
The following description may use terms such as “horizontal”, “vertical”, “lateral”, “back and forth”, “up and down”, “upper”, “lower”, “inner”, “outer”, “forward”, “rear”, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.
The perforating tool 8 and the tubular pulling tool 6 may be lowered down in the tubular with a work string 7 to a predefined/desired depth. The tubular pulling tool 6 is connected to the tubular (2) and a pulling tension is maintained on the tubular. The tubular 2 may be cut around its circumference. The cut 9 may be formed in a separate run prior to lowering the work string (7) into the well (100). The cut 9 may be formed by a cutting tool which may be attached to or may be part of the perforating tool and may be formed upon or simultaneously with the perforations 10.
It is important to understand that “cut” does not have to go entirely through the section of tubular 2. The purpose of the cut 9 is to create enough weakness in the tubular 2 such that when that when pulling tension is maintained and the perforation guns activate, the tubular 2 can be pulled free from the well.
The amount of weakness that is formed in the tubular from the cut will be determined by several factors. Some examples of these factors include the thickness of the tubular wall, the material of the tubular, the angle of the cut, the age and strength of the cement, pressure on the tubular, amount of force that the pulling tool can apply. The calculation of these factors and establishment of how much weakness is enough is well within the ability of one skilled in the art.
The cut 9 can be formed with a cutting tool that cuts entirely through the wall of the tubular 2 around the circumference of the pipe. But it can also be formed with by the cutting tool cutting partway through the tubular 2 wall. Another option is to form the cuts at intervals around the circumference of the tubular 2 (either all the way or part of the way through). It can also be formed by an arrangement of charges on the perforation gun itself or as another tool on the same work string. The arrangement could produce the cut 9 entirely around the circumference of the tubular 2 or by creating enough holes in the tubular 2 wall that the tubular 2 can be pulled out during operation. It can be easier to form a cut 9 simultaneously with the activation of the perforating tool 8 by using an arrangement of charges, rather than a cutting tool.
A combination of cutting tool and charges can be used to create the required weakness formed by the cut. The cut can also be at an angle with respect to the longitudinal axis of the tubular.
Both a cutting tool and an arrangement of charges are examples of a means to create a weakness in a tubular. Normally it is at the cut where the separation of the tubular 2 to be pulled from the rest of the entire length of pipe within the well will occur. However, these can be some arrangements, where the separation will occur in the neighboring region of the cut, but not precisely on it. For example, the perforating tool forming the cut can be two or more rows of perforations around the circumference at different heights within the tubular 2. The separation could occur between the rows, rather than on a single specific row. Another example could be that more than one cut is made by the cutting tool.
While the figures show that the cut 9 is formed in the tubular 2 before the operation of activation of the perforation gun, this is not the case. It is possible for the cut to be formed at the same time as the activation of the perforation gun. This has the advantage of the entire operation being possible in a single run. If the cut is made by the cutting tool, on the same work string as the perforation gun, it will normally be arranged below the perforation gun. However, it is possible for the cutting tool to be arranged above the perforation gun depending on how the work string is going to be operated.
After the perforating tool 8 and the tubular pulling tool 6 is lowered down in the tubular 2, tubular pulling tool 6 is activated so that it attaches to the tubular (2) and a pulling tension is introduced to the tubular 2. Due to the friction force between the outer surface of the tubular 2 and the material in the anulus (3) the tubular (2) is prevented from moving,
In an alternative embodiment, dynamic under balance is introduced. By introducing dynamic under balance when perforating the settled solids in the annulus 3 may be broken up further and reduce the friction even further.
The present disclosure in some embodiments provides a method for pulling tubulars out of a subterranean well, the method comprising the steps of: i) lowering a work string into the subterranean well, the work string comprising a perforating tool for perforating the tubular, and a tubular pulling tool configured to engage with the inside of and pull tubulars out of the subterranean well; ii) connecting the tubular pulling tool to the tubular; iii) activating the perforating tool to form plurality of perforations extending from an inner wall of the tubular through a material deposited in an annulus defined between the tubular and an outer tubular; iv) immediately upon activating the perforating gun and while maintaining pulling tension to the tubular, ripping the tubular on the work string out of the subterranean well without fluid circulation from the surface.
An embodiment of the present disclosure is a method wherein the work string further comprising a tubular cutting tool configured for circumferentially cutting the tubular. An embodiment of the present disclosure is a method wherein the work string further comprising a surge tool comprising a fluid chamber. An embodiment of the present disclosure, after step ii), forming the tubular a cut with the tubular cutting tool. An embodiment of the present disclosure is a method wherein the inner tubular is a production tubing and the outer tubular is a casing. An embodiment of the present disclosure is a method wherein, before step i), installing a seal a location below the tubular that is removed without fluid circulation from the surface.
Another embodiment of the present disclosure is a system for pulling tubulars in a subterranean well, the system comprising a perforating tool for perforating the tubular; a tubular pulling tool configured for pulling the tubular out of the subterranean, a cutting tool configured for forming a cut of the tubular, a surge tool comprising a fluid chamber with an internal pressure that is lower than the well pressure and the pressure in an annulus defined between the tubular and an outer tubular, wherein the perforating tool and the tubular pulling tool, the cutting tool and the surge tool are attached to a work string characterized in that the system not comprising a fluid circulation arrangement from the surface.
An embodiment of the present disclosure, the surge tool is comprising a fluid chamber. An embodiment of the present disclosure, the perforating tool is comprising one or more perforating guns. An embodiment of the present disclosure, the perforating tool is configured for forming the cut on the tubular. An embodiment of the present disclosure, the inner tubular is a production tubing. An embodiment of the present disclosure, the outer tubular is a casing.
While it is an advantage that a tubular can be pulled without fluid circulation from the surface into the annulus, there could be situations where this could be advantageous. It may be possible that a tubular is difficult to pull and the fluid circulation will make this easier.
While the present disclosure has been described with reference to the embodiment illustrated, it should be understood that modifications and/or additions can be made to the device, which remain within the field and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20191518 | Dec 2019 | NO | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NO2020/050316 | 12/16/2020 | WO | 00 |
