NO20181113A1 - Method for closing drilled holes - Google Patents
Method for closing drilled holes Download PDFInfo
- Publication number
- NO20181113A1 NO20181113A1 NO20181113A NO20181113A NO20181113A1 NO 20181113 A1 NO20181113 A1 NO 20181113A1 NO 20181113 A NO20181113 A NO 20181113A NO 20181113 A NO20181113 A NO 20181113A NO 20181113 A1 NO20181113 A1 NO 20181113A1
- Authority
- NO
- Norway
- Prior art keywords
- reaction
- well
- reactants
- basis
- supporting structure
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000006243 chemical reaction Methods 0.000 claims abstract description 53
- 239000000376 reactant Substances 0.000 claims abstract description 13
- 238000007789 sealing Methods 0.000 claims abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 14
- 238000007133 aluminothermic reaction Methods 0.000 claims description 9
- 239000007795 chemical reaction product Substances 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 7
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 238000013016 damping Methods 0.000 claims description 5
- 239000002893 slag Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 4
- 238000005204 segregation Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 239000003832 thermite Substances 0.000 abstract description 21
- 239000000463 material Substances 0.000 abstract description 7
- 239000000758 substrate Substances 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 11
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000003129 oil well Substances 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 229910001152 Bi alloy Inorganic materials 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000003892 spreading Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000927 Ge alloy Inorganic materials 0.000 description 1
- 206010024769 Local reaction Diseases 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B29/02—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 by explosives or by thermal or chemical means
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices, or the like
- E21B33/134—Bridging plugs
Abstract
For the permanent closure of drilled holes at a chosen location, there is proposed a method in which a support structure is first created at that location, onto which support structure a cast body is formed by means of a first aluminothermic process, a retardant being added to the reactants of this process, the cast body sealing and closing the drilled hole and serving as a substrate for the main reaction, involving a second aluminothermic process, for creating the permanent closure. The material nature of the cast body makes it able to withstand the thermal and mechanical stresses of the main reaction, and in particular to reliably prevent the thermite melt running into the drilled hole.For the permanent closure of drilled holes at a chosen location, a method is proposed in which a support structure is first created at that location, onto which support structure a cast body is formed by means of a first aluminothermic process, a retardant being added to the reactants of this process, the cast body sealing and closing the drilled hole and serving as a substrate for the main reaction, involving a second aluminothermic process, for creating the permanent closure. The material nature of the cast body makes it able to withstand the thermal and mechanical stresses of the main reaction, and in particular to reliably prevent the thermite melt running into the drilled hole.
Description
DESCRIPTION
Method for closing wells
The invention relates to a method corresponding to the preamble of claim 1.
For reasons including economic considerations, the use of gas or oil wells is limited in time, abandoned wells having to be reliably sealed in order to prevent liquid or gaseous substances that are possibly environmentally harmful, in particular contain hydrocarbons, from escaping and spreading unchecked. A comparative task is also faced when, for whatever reasons, a sealed well is to be reopened and put to use.
A series of techniques are known for sealing wells, in particular for setting well seals, the implementation of which includes the use of a heat source, in many cases making use of the thermite reaction known per se, which forms the basis of aluminothermal welding and is used extensively in track construction for welding the ends of rails. The thermite reaction is a redox reaction, in which aluminium is used as a reducing agent for reducing iron(III) oxide to iron. The reaction products of this highly exothermic reaction are elemental iron and a slag of aluminium oxide, which are initially in a molten state, the slag floating on the iron because of its lower density. The starting product of the thermite reaction is a powdered substance mixture consisting of aluminium and iron oxide, known as the welding portion, the heat that is required for initiating the reaction being applied by means of a chemical or electrical detonating means.
WO 2013/135583 A2 discloses a method for permanently sealing a well and/or partially removing parts of a wall of the well, wherein surrounding materials and/or parts of the wall of the well at a chosen location of the well are melted by using an ignitable compound that is suitable for producing an exothermic reaction, and forming a seal of the well at this location once they have cooled down. The compound mentioned may be a thermite mixture, which releases the heat required in the course of the aluminothermic reaction. In order to spatially confine the region that is influenced by the heat released, extending from the location at which a seal is to be created, the thermite mixture, provided with an igniting head, lies directly against a heatresistant plate-shaped element consisting of ceramic or glass from above and below within the well, and the heatresistant element in turn lies against a likewise plateshaped sealing element from above and below. While the two heat-resistant elements spatially confine the thermal effect of the reaction in the longitudinal direction of the well, the two sealing elements are intended to produce a seal above and below the reaction site of the thermite reaction and are made of appropriate materials. The actual permanent seal of the well is formed by a substance mixture consisting of the reaction products of the thermite reaction and parts of the wall of the well and of the rock surrounding the well. In view of the density of the iron developed as a result of the reaction, which is high in comparison with the materials of the plate-shaped elements performing the function underneath of a support for the reaction mentioned, its mass and in particular its initial temperature, there are uncertainties as to whether the elements mentioned can perform sufficiently reliably the functions assigned to them in the context of this concept.
US 2015/0368542 A1 discloses a method for closing and opening gas or oil wells in which a thermite mix is used as a heat source in conjunction with a damping agent intended for lowering the temperature of the thermite reaction, such as for example sand. The thermite mix is used in the form of blocks, in order to ensure a homogeneous state of mixing, a number of blocks being put together and intended to influence the local reaction temperature occurring in the thermite reaction by means of the composition of the blocks, to be specific the proportion of the damping agent. According to this document, a permanent seal or plug of the well consists of an alloy of bismuth and germanium, which makes it possible to set suitable melting temperatures, the composition of the multiple blocks that are used simultaneously and have different compositions being based on the task to be achieved, to be specific whether such a seal is to be set or removed. Taking into consideration the fact that the characteristics of the rock along the well, in particular the local heat dissipating conditions, are often not sufficiently known, there are also uncertainties with regard to the temperatures occurring locally as a result of the thermite reaction.
It is characteristic of these known methods that a seal consisting of the reaction products of the thermite reaction is to be formed at a predetermined location of the well, possibly incorporating parts of the wall of the well, the region along the well in which there is an input of heat from the thermite reaction being confined from above and below by inserting structural elements with an insulating effect. This requires an at least temporarily effective seal of the well at the bottom, which is protected by the intermediate arrangement of a refractory layer that is not impaired by the temperatures of the thermite reaction. This seal forms the basis for the thermite reaction and it must be suitable for reliably withstanding all of the mechanical loads that are produced by the thermite reaction, caused by the density of the molten iron and thermal loads caused by the reaction temperature. It should be taken into consideration here that the properties of the rock adjacent to the wall of the well are not always known sufficiently for the question of heat input, and the associated spatial formation of a heat input zone. This in turn is of significance for the temperature zone produced by the reaction. In particular, it must be ensured that the thermite melt is prevented from running out into the well. It is not ensured in all cases that such a temporary seal can dependably withstand all of the mechanical and thermal loads.
WO 2011/151271 A1 discloses a method and a device for setting a seal or for removing a seal of gas or oil wells, wherein a cylindrical plug consisting of steel bears a eutectic bismuth alloy on the outside and is designed on the inside for detachable connection to a heat source. The heat source may be an electrical heat source or alternatively the heat required may also be provided by means of a chemical reaction. For setting a seal, the plug bearing the alloy mentioned is lowered into the well to the location at which a seal is to be set, wherein the alloy is subsequently melted by supplying heat, the annular space between the wall of the well and the plug is filled under the effect of gravitational force and a seal of the annular space forms as a result of volume expansion after cooling down has occurred. The heat source can subsequently be removed. For removing such a seal, such a heat source is introduced into the seal, the alloy that fills the annular space being melted by an input of heat, so that it comes away from the wall of the well and the seal can subsequently be removed from the well.
The object of the invention is to devise a method of the type referred to at the beginning with a view to producing reproducible process conditions for an underlying aluminothermic reaction as a heat source and the production of a reliable seal of a well that is stable over time, wherein in particular thermite melt is reliably prevented from running out into the well. This object is achieved in the case of such a method by the features of the characterizing part of claim 1.
It is accordingly essential to the invention that, for setting a seal, two reactions are used one after the other in time, to be specific, as preparation in a first step, a thermochemical, in particular exothermic reaction, which is aimed at the formation of a refractory shaped body, which forms a tight seal of the well on a supporting structure created within the well. This shaped body also forms at the respective location the basis on which, in a second step, the subsequent aluminothermic main reaction is carried out, the reaction products of which form the permanent seal of the well. It is of essential importance that the reactants of the thermochemical reaction are selected on the basis of producing a shaped body which is not melted at the temperatures of the main reaction and with which in particular undercutting by molten steel is prevented. The supporting structure must have such characteristics that any loads resulting from the thermochemical reaction are withstood and a shaped body that is suitable for plugging the well in a sealing manner can be formed. The shaped body forms a basis for the main reaction which, in the course of the aluminothermic reaction thereof, makes it possible on the basis of the local heat dissipating conditions for the wall of the well and/or parts of a tubular of the well to be melted, though spreading of the thermite melt in the longitudinal direction of the well is reliably prevented by the shaped body just as excessive thermal influencing of the supporting structure is reliably prevented.
According to the features of claim 2, the supporting structure is formed by a temporary sealing element which is overlaid by a refractory layer. The sealing element must be fixed here in a suitable way within the well.
According to the features of claim 3, the reactants of the thermochemical reaction are chosen on the basis of achieving the effect that the shaped body lies against the wall of the well in a sealing manner, and that there is a solid connection therewith which can withstand loads, but on the other hand, unlike in the case of the main reaction, melting of the same is avoided.
According to the features of claim 4, the reactants of the thermochemical reaction are chosen on the basis of achieving the effect that the shaped body lies against the wall of the well in a sealing manner, and that there is a solid connection therewith which can withstand loads, but on the other hand, unlike in the case of the plugging reaction, melting of the same is avoided.
According to the features of claim 5, the thermochemical reaction is an aluminothermic reaction, the reactants of which additionally contain a damping agent that lowers the reaction temperature. The reactants of the aluminothermic reaction are used in the form of granules or powder, it being possible for the reaction sequence, in particular including the reaction temperature, to be influenced by means of the quantitative composition and also the grain size distribution. The aim here is to obtain a moulded body with a material structure in the manner of a metal/metal-oxide matrix which binds in the reaction products, which in any event can no longer be melted by the subsequent main reaction. The temperature that develops thereby can also be estimated, as can its influence on the supporting structure mentioned, by the amount of the reactants underlying this aluminothermic reaction and their composition.
According to the features of claim 6, the characteristics of the reactants in the course of the aluminothermic reaction that forms the thermochemical reaction are set so as to suppress, at least substantially, a segregation of slag, iron and other reaction products. Under given heat dissipating conditions of the wall of the well or of the tubular of the well, this can be achieved by providing rapid cooling, the slag solidifying first because of its high melting point, with the effect that a sponge-like material skeleton is created before segregation of the various components can occur. A shaped body formed in this way is in any event unable to be completely melted once again by the subsequent aluminothermic plugging reaction.
The uncertainties concerning the function of the supporting structure that exist because of the unknown local heat dissipating conditions of the well are consequently countered by the formation of a shaped body which, on the basis of its material-related characteristics, withstands the thermal and mechanical loads of the plugging reaction.
Claims (6)
1. Method for producing a permanent seal at a chosen location of a well, wherein a supporting structure is produced at this location, wherein an aluminothermic main reaction which is aimed at producing the seal and the reaction product of which forms the seal of the well after cooling down is carried out on the supporting structure, characterized in that, at a time before the main reaction, a thermochemical reaction is initiated on the supporting structure, the reactants and heat of reaction of which are set on the basis that, after cooling down of its reaction products, there forms a refractory shaped body which closes the well in a sealing manner, forms a basis for the main reaction and provides protection for the supporting structure, and the melting temperature of which is sufficiently high to withstand the thermal loads of the main reaction.
2. Method according to claim 1, characterized in that, for producing the supporting structure, a temporary sealing element which is overlaid by a refractory layer and fixed in the well is introduced into the well.
3. Method according to claim 1 or 2, characterized in that the reactants of the thermochemical reaction are chosen on the basis of achieving the effect that the shaped body lies against the wall of the well in a sealed manner, while to the greatest extent avoiding melting of the same.
4. Method according to claim 1 or 2, characterized in that the reactants of the thermochemical reaction are chosen on the basis that the shaped body enters into a solid and sealing connection with a tubular of the well.
5. Method according to one of claims 1 to 4, characterized in that an aluminothermic reaction, the reactants of which contain a damping agent, is used as the thermochemical reaction.
6. Method according to one of claims 5, characterized in that the grain size of the reactants and of the damping agent of the aluminothermic reaction is chosen on the basis of substantially suppressing a segregation of slag, iron and other reaction products.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102016003609.5A DE102016003609A1 (en) | 2016-03-29 | 2016-03-29 | Method for closing boreholes |
| PCT/EP2017/000277 WO2017167431A1 (en) | 2016-03-29 | 2017-03-01 | Method for closing drilled holes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NO20181113A1 true NO20181113A1 (en) | 2018-08-24 |
Family
ID=58264463
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO20181113A NO20181113A1 (en) | 2016-03-29 | 2018-08-24 | Method for closing drilled holes |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE102016003609A1 (en) |
| NO (1) | NO20181113A1 (en) |
| WO (1) | WO2017167431A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2480869B (en) | 2010-06-04 | 2017-01-11 | Bisn Tec Ltd | Method and apparatus for use in well abandonment |
| NO334723B1 (en) | 2012-03-12 | 2014-05-12 | Interwell Technology As | Procedure for plugging and leaving a well |
| GB201223055D0 (en) | 2012-12-20 | 2013-02-06 | Carragher Paul | Method and apparatus for use in well abandonment |
| US9394757B2 (en) * | 2014-01-30 | 2016-07-19 | Olympic Research, Inc. | Well sealing via thermite reactions |
-
2016
- 2016-03-29 DE DE102016003609.5A patent/DE102016003609A1/en not_active Withdrawn
-
2017
- 2017-03-01 WO PCT/EP2017/000277 patent/WO2017167431A1/en active Application Filing
-
2018
- 2018-08-24 NO NO20181113A patent/NO20181113A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| WO2017167431A1 (en) | 2017-10-05 |
| DE102016003609A1 (en) | 2017-10-05 |
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| Date | Code | Title | Description |
|---|---|---|---|
| FC2A | Withdrawal, rejection or dismissal of laid open patent application |