The present invention relates to an annular barrier to be expanded in an annulus between a well tubular structure and an inside wall of a borehole downhole for providing zone isolation between a first zone and a second zone of the borehole.
Furthermore, the invention relates to a downhole system and a method of expanding an annular barrier.
When completing a well, production zones are provided by submerging a casing string having annular barriers into the borehole of the well. When the casing string is in the right position in the borehole, the annular barriers are expanded or inflated. The annular barriers are in some completions expanded by pressurised fluid, which demands a certain amount of additional energy in order to pressurise the well tubular structure to a pressure sufficient to expand a metal sleeve of the annular barrier.
It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide an improved annular barrier using an energy resource which is present at the well site, so that no, or not as much, additional energy is needed as in the known solutions, or so that the expansion of the annular barrier is performed with the thermal energy drawn from the downhole environment.
The above objects, together with numerous other objects, advantages and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by an annular barrier to be expanded in an annulus between a well tubular structure and an inside wall of a borehole downhole for providing zone isolation between a first zone and a second zone of the borehole, the annular barrier comprising:
This compound may be thermally decomposable below a temperature of 400° C.
In an embodiment, the compound may comprise nitrogen.
Also, the compound may comprise nitrogen in the form of ammonium, nitrite, azide or nitrate.
Furthermore, the compound may be selected from a group consisting of: ammonium dichromate, ammonium nitrate, ammonium nitrite, barium azide, sodium nitrate, or a combination thereof.
Also, the compound may decompose at temperatures above 100° C., preferably above 180° C.
In addition, the annular space may be pre-pressurised to a pressure above 5 bar, preferably above 50 bar and more preferably above 100 bar, even more preferably above 250 bar.
Moreover, the compound may be present in the form of a powder, a powder dispersed in a liquid or a powder dissolved in a liquid.
Furthermore, the compound may be present in solid or liquid form.
Additionally, the space may be filled with the compound.
Further, the compound may be in a solid state.
Also, the compound may be insoluble.
The annular space may further comprise a fluid.
Furthermore, the compound may further comprise a catalyst.
By having a catalyst, the temperature at which the compound decomposes is decreased or increased.
Moreover, the annular barrier as described above may further comprise an opening in the tubular metal part and/or in the expandable sleeve.
Said opening may be arranged in the tubular metal part opposite the expandable sleeve for letting fluid directly into the annular space.
Additionally, sealing elements may be arranged on the outer face of the expandable sleeve.
Also, the annular barrier may comprise a chamber filled with a second compound, and the annular space may be filled with the first compound.
Additionally, the first and second compounds may be calcium carbonate and hydrochloric acid, respectively.
In addition, the chamber may be arranged in the connection part.
Furthermore, the chamber and the annular space may be divided by a shear pin.
Also, the annular space may comprise several chemicals which are already mixed into the compound and which react when heated to a certain temperature.
Additionally, the chemicals may be diesel and oxygen, e.g. in the form of air, reacting at a temperature around 210° C.
Furthermore, the chemicals may be diethyl ether and oxygen, e.g. in the form of air, reacting at a temperature around 160° C.
In addition, the annular space may comprise more than one chemical, and a spark or electrical ignition may start a reaction therebetween, creating an increased volume and an expansion of the annular barrier.
Further, the chemicals may be sodium chlorate, barium peroxide and potassium perchlorate.
Also, the annular barrier may further comprise a one-way valve.
In an embodiment, the one-way valve may be arranged in the opening.
Furthermore, the one-way valve may be arranged in the connection part.
Additionally, the one-way valve may be an overpressure valve.
The annular barrier may further comprise a heating wire arranged in or in abutment to the tubular metal part.
Moreover, the tubular metal part may comprise an electrical wire.
The electrical wire may be arranged in a groove or channel in the tubular metal part or the electrical wire may be embedded in the tubular metal part.
Also, one connection part may be slidably connected with the tubular metal part.
Furthermore, the expandable sleeve may be an expandable metal sleeve.
The present invention furthermore relates to a downhole system comprising:
In an embodiment, the well tubular structure may be filled with a fluid having a temperature above 110° C., preferably a temperature above 180° C., and more preferably a temperature above 250° C.
In addition, the fluid may be steam.
The downhole system may further comprise a tool comprising a heating unit for heating the tubular metal part of the annular barrier from within the well tubular structure.
The heating unit may be an immersion heater, a heat exchanger, a blower or the like.
Moreover, the tool may comprise isolation means for isolating a zone in the well tubular structure opposite the expandable space of the annular barrier.
Also, the heating unit of the tool may comprise a heating wire adapted to be arranged in abutment to the tubular metal part.
The tool may comprise a positioning device, such as a magnetic profiler or a casing collar locator.
Furthermore, the tool may be adapted to abut the one-way valve in the tubular metal part to provide heat to the annular space through the one-way valve.
Also, the heat may come from the fluid being hot steam, the hot steam having a temperature above 180° C.
Additionally, the tool may comprise inflatable seals.
Furthermore, the tool may comprise a pump, a motor for driving the pump, and an electronic section connected and powered through a wireline.
Moreover, the tool may be adapted to abut the one-way valve in the tubular metal part by means of a projectable arm to provide heat to the annular space through the one-way valve.
In addition, the tool may comprise a contact means adapted to electrically connect to the wire via a fluid-tight electrical contact.
The contact means may also be an induction element.
In an embodiment, the tool may further comprise a flow line which is in fluid communication with the annular space.
Also, the tool may comprise a contact means adapted to electrically connect to the wire.
The well tubular structure may be connected with a heating device at surface or seabed.
Moreover, the well tubular structure may be connected to a tubing, such as a drill pipe, for submerging the well tubular structure, the tubing being connected with a heating device at surface or seabed.
The present invention furthermore relates to a method of expanding an annular barrier as described above, comprising the steps of:
The heat may be increased to a temperature above 180° C. before being provided to the annular space.
The method as described above may further comprise the step of filling the expandable space with at least one thermally decomposable compound, which compound is thermally decomposable below a temperature of 400° C.
Also, the method as described above may further comprise the step of mounting the tubular metal part as part of the well tubular structure.
Moreover, the method as described above may comprise the step of pressurising the tubular metal part and the well tubular structure.
Additionally, the method as described above may comprise the step of isolating a zone opposite the opening of the annular barrier by means of a tool.
Furthermore, the method as described above may comprise the step of pressurising fluid within the zone.
In addition, the tool may comprise a pump for pressurising the fluid.
This tool may be connected by tubing to a pump arranged at surface or seabed.
The method as described above may further comprise the step of letting pressurised fluid in through an opening in the tubular metal part and into the space.
Said opening may be arranged opposite the expandable space for letting pressurised fluid directly into the annular space.
Moreover, the step of providing heat to the annular space may be performed by letting pressurised fluid in through an opening in the tubular metal part and into the space, the pressurised fluid having a temperature above 100° C.
Finally, the present invention relates to a method of manufacturing an annular barrier as described above, comprising the steps of:
The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which
All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.
The compound 16 decomposes when heated to above a certain temperature within a temperature range of 100-400° C. and is then decomposed into gas or super-critical fluid and e.g. water, and as the compound generates gas or super-critical fluid, the volume of the compound increases. In this way, the annular space increases and the expandable sleeve 8 is expanded, as shown in
Furthermore, the expandable sleeve 8 may be made of metal, and because the compound 16 expands the sleeve when heated, the expandable sleeve may be welded or in another way fixedly connected to the tubular metal part 7 with or without connection parts. Thus, the risk of leaks is further diminished.
The compound 16 comprised in the space 15 comprises nitrogen, such as in the form of ammonium, nitrite, azide, or nitrate, and may be selected from a group of ammonium dichromate, ammonium nitrate, ammonium nitrite, barium azide, sodium nitrate, or a combination thereof. These nitrogen-containing compounds decompose when heated at a temperature below 400° C., e.g. by flushing the casing with hot steam or a heated liquid which heats the compound 16 by heating the tubular metal part 7. At many well sites, hot steam is available as it is used for bringing up the hydrocarbon-containing fluid from the reservoir and can therefore also be used for expanding the annular barriers.
The compound 16 in the space may be present in the form of a powder, a powder dispersed in a liquid or a powder dissolved in a liquid. Thus, the compound 16 may be in a solid or liquid state, e.g. dispersed or dissolved in a liquid which may be water, mud or well fluid. As the compound 16 is heated, the compound decomposes into gas or super-critical fluid and water, and the expandable sleeve 8 is expanded. Whether it is gas or super-critical fluid depends on the pressure present downhole. The amount of compound in the space is determined by the expected pressure downhole, and if the pressure is higher than expected, the decomposition could create a super-critical fluid instead of a gas.
The compound decomposes at temperatures above 100° C. and below 400° C., preferably above 150° C. and more preferably above 180° C. The injected steam or heated fluid has a temperature around 250° C. which is sufficient to heat the compound 16 arranged in the space of the annular barrier 1 to above 200° C. Furthermore, the heat can be provided by locally heating the tubular metal part 7 and/or heating the fluid in the well tubular structure opposite the tubular metal part.
The compound may comprise a catalyst, and by having such a catalyst, the temperature at which the compound decomposes can be increased or decreased depending on the temperature conditions in the borehole. In this way, the annular barrier can be designed to a variety of well conditions.
When completing a well, the tubular metal part 7 is mounted as part of the well tubular structure and lowered into the borehole as part of the well tubular structure, e.g. by connecting the well tubular structure to a tubing, such as a drill pipe. Before inserting the annular barriers 1, the annular space may be pre-pressurised to a pressure above 5 bar, preferably above 50 bar and more preferably above 100 bar. By pre-pressurising the annular space 15, the expansion ratio provided by the decomposition of the compound 16 can be decreased, and the expansion can thus be controlled to a higher degree than when the space is not pre-pressurised.
In
The first and second compounds may be calcium carbonate and hydrochloric acid which, when mixed, react (and do not decompose) and generate calcium chloride, water and carbon dioxide and thereby create an increased volume resulting in an expansion of the annular barrier 1.
In another embodiment, the annular space 15 comprises several chemicals which are already mixed into the compound and which react when heated to a certain temperature and thermally decompose.
Furthermore, the first and second compounds could be chemicals mixed into the annular space 15 and could be diesel and oxygen, e.g. in the form of air, reacting and not decomposing at a temperature of 210° C., and thereby creating an expansion of the expandable sleeve. The chemicals, i.e. the first and second compounds, could also be diethyl ether and oxygen, e.g. in the form of air, reacting at a temperature of 160° C.
Also, the annular space 15 may comprise more than one chemical, and a spark or electrical ignition could start a chemical reaction (not decomposition) between the chemicals, creating an increased volume resulting in an expansion of the annular barrier 1. The chemicals could be sodium chlorate, barium peroxide and potassium perchlorate.
In addition, the annular space 15 may be filled with water, and by using electricity through wires on the outside of the well tubular structure 3, hydrogen and oxygen are generated via electrolysis.
As shown in
In
In order to heat the compound 16 in the annular space 15 of the annular barrier 1 locally, the tubular metal part 7 further comprises a heating wire 19, such as an electric wire, arranged as shown in the cross-sectional view of
The downhole system 100 shown in
In
In
The system 100 may further comprise a flow line 30 (shown in
The annular barrier 1 is expanded by providing heat to the annular space so that the thermally decomposable compound 16 present in the annular space starts to decompose and generate gas or super-critical fluid, thereby causing the expandable sleeve 8 to expand. The compound 16 is provided in the annular space 15 before the annular barrier 1 is mounted as part of the well tubular structure.
The annular barrier 1 is mounted by providing a tubular metal part 7 and arranging an expandable sleeve 8, e.g. made of metal, in such a way that the sleeve surrounds the tubular metal part 7, whereby an annular space 15 is created between the tubular metal part and the expandable sleeve. Then, at least one thermally decomposable compound 16 is provided in the annular space 15.
The annular barrier 1 may further comprise a one-way valve 17 arranged in an opening 18 in the tubular metal part 7. In this way, the fluid, e.g. hot steam, can be injected directly into the annular space to heat the compound 16 in order to force the compound to decompose and expand the expandable sleeve 8 to abut the inside wall of the borehole 6.
In
As shown in
By fluid or well fluid is meant any kind of fluid that may be present in oil or gas wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By gas is meant any kind of gas compound present in a well, completion, or open hole, and by oil is meant any kind of oil compound, such as crude oil, an oil-containing fluid, etc. Gas, oil, and water fluids may thus all comprise other elements or compounds than gas, oil, and/or water, respectively.
By a casing is meant any kind of pipe, tubing, tubular, liner, string etc. used downhole in relation to oil or natural gas production.
In the event that the tool is not submergible all the way into the casing, a downhole tractor can be used to push the tool all the way into position in the well. The downhole tractor may have projectable arms having wheels, wherein the wheels contact the inner surface of the casing for propelling the tractor and the tool forward in the casing. A downhole tractor is any kind of driving tool capable of pushing or pulling tools in a well downhole, such as a Well Tractor®.
Although the invention has been described in the above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.
Number | Date | Country | Kind |
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13186654.3 | Sep 2013 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2014/070738 | 9/29/2014 | WO | 00 |