The invention also relates to a method for providing a controllable fluid flow between a hydrocarbon reservoir and a production tubing in a well in the hydrocarbon reservoir, by using a sleeve valve.

When exploiting hydrocarbons from hydrocarbon reservoirs, wells are drilled from the sea bed or the earth surface down to and into the reservoir, which is under pressure. The part of the well which extends from the sea bed or the earth surface to the reservoir is lined with casing in order to prevent the well from collapsing.

Production tubing is placed inside the casing, the production tubing extends from the sea bed or the earth surface, past the end of the casing and into the reservoir.

In order to control the inflow of fluids from the reservoir, it is desirable to be able to close and open the inflow to the production tubing at different places along the part of the production tubing which is located in the reservoir.

In order to control the flow to or from a production tubing, sleeve valves can be used, comprising an outer sleeve and an inner sleeve which are both provided with openings. The outer sleeve is stationary and may form a part of the production tubing, while the inner sleeve is movable in order to bring the openings of the two sleeves in and out of registering, to open or close for flow, respectively, through the sleeve valve.

The production tubing may extend through different production zones, and may have one or several sleeve valves in each production zone. The production zones may have different pressures, and in order to prevent the hydrocarbons from flowing between the production zones on the outside of the tubing, the space between the production tubing and the well wall may be closed off by isolation packers or filled with concrete, usually known as cementing. The concrete can be filled through a valve in the production tubing, and concrete will then flow up on the outside of the tubing. In addition to preventing flow of hydrocarbons between the production zones, the concrete also prevents flow of hydrocarbons from the reservoir to the production tubing, and therefore the concrete must be perforated in

the areas in which inflow to the production tubing is desired. This perforation can be done by a perforating gun, which shoots projectiles into the concrete. A perforating gun can, however, not easily be combined with a sleeve valve, since the projectiles would destroy the sleeve valve.

In order to maintain the pressure in the reservoir, some places water or gas injection is used, i. e. pressurized water or gas is forced into the reservoir from the well, and it can then be desirable to control the outflow from the well along the production tubing. Sleeve valves can also be used for this purpose, but the use of sleeve valves will also in this case be associated with the above mentioned problem related to cementing of the well.

GB 2 201 979, US 4 782 896 and US 4 921 044 describe sleeve valves for controlling fluid flow between a hydrocarbon reservoir and a well in the hydrocarbon reservoir, comprising a stationary outer sleeve and an inner sleeve which is movable between positions in which openings in the outer sleeve and the inner sleeve register or do not register.

The problem of establishing a fluid flow between a hydrocarbon reservoir and a production tubing in the reservoir, in which the space between the production tubing and the well wall is filled with concrete, is discussed in US 5 425 424. It is here described a device comprising a sliding sleeve valve, the valves comprise radially movable pistons which can be used for cracking the concrete. The pistons simultaneously eject grease, which forces concrete away and also acts as a curing inhibitor for the concrete.

US 5 533 570 describes an apparatus for down hole injection and mixing of fluids in a concrete slurry. The fluid is kept in a chamber, and may be injected in uncured concrete located on the outside via electro-magnetic valves.

The object of the invention is to provide a solution to the above mentioned problem of using sleeve valves in a production tubing, in which the space between the production tubing and the well wall is filled with concrete. The object of the invention is further to provide a method for providing a controllable fluid flow between a hydrocarbon reservoir and production tubing in a well in the hydrocarbon reservoir, by using a sleeve valve, in which the space between the production tubing and the well wall is filled with concrete.

According to the invention the objects are achieved by a sleeve valve and a method of the type mentioned in the introduction, which are characterised by the features of the claims.

The invention thus relates to a sleeve valve for controlling fluid flow between a hydrocarbon reservoir and production tubing in a well in the hydrocarbon reservoir, the sleeve valve comprises an outer sleeve and an inner sleeve, each having at least one opening, the inner sleeve is by means of an actuator or a tool movable between an open position in which the opening of the inner sleeve registers with the opening of the outer sleeve, and a closed position in which the opening of the inner sleeve does not register with the opening of the outer sleeve, and possibly intermediate positions. The sleeve valve comprises at least one chamber for concrete-curing inhibitor, and at least one passage from the chamber for concrete- curing inhibitor to at least one injection outlet on the outside of the inner sleeve, the injection outlet registers with the outer sleeve's opening when the inner sleeve is moved to an injection position. The sleeve valve further comprises at least one actuator for ejecting concrete-curing inhibitor from the chamber, through the passage, the injection outlet and the opening in the outer sleeve, for injecting concrete-curing inhibitor into uncured concrete outside the outer sleeve.

The injection of the concrete-curing inhibitor in the uncured concrete will take place during cementing of the space between the production tubing and the well wall. It is thereby established an area outside the opening in the outer sleeve in which the concrete does not cure or only cures to a limited extent, and fluids are thereby allowed to flow between the reservoir and the sleeve valve, i. e. the opening in the outer sleeve.

The invention also relates to a method for providing a controllable fluid flow between a hydrocarbon reservoir and production tubing in a well in the hydrocarbon reservoir, by using a sleeve valve according to the invention.

According to the method of the invention, the following steps are carried out: integrating the sleeve valve in a production tubing, and placing the production tubing in the well in the hydrocarbon reservoir, in a per se known way, the sleeve valve's chamber for concrete-curing inhibitor is filled with concrete- curing inhibitor, and the inner sleeve is located in an injection position, filling the space between the production tubing with the sleeve valve and the well wall with liquid uncured concrete, activating the actuator for ejecting concrete-curing inhibitor from the chamber, causing the concrete-curing inhibitor to be injected in the concrete and form open areas which allow fluid flow between the reservoir and the opening in the outer sleeve, moving the inner sleeve to an open position, for establishing an initial fluid flow between the reservoir and the opening in the outer sleeve, whereupon the inner sleeve can be moved to a desired position, for establishing a desired fluid flow.

During the initial fluid flow uncured concrete which has been affected by the concrete-curing inhibitor is flushed out of the area outside the opening in the outer sleeve, in through the opening in the outer sleeve and out of the well. During the following regulation of the sleeve valve, the inner sleeve may be brought to a position in which the opening in the inner sleeve totally or partly registers with the opening in the outer sleeve, for regulating the fluid flow to desired value.

The outer sleeve and the inner sleeve may have one or several openings which register with corresponding openings in the inner sleeve or the outer sleeve, respectively. The openings in the sleeves may be arranged in rows along the sleeves, and may be arranged symmetrically around the sleeves. The inner sleeve may be movable by being rotatable about the longitudinal direction of the production tubing, the inner sleeve may be slidable in the longitudinal direction of the production tubing, or the inner sleeve may be movable along a helix in the longitudinal direction of the production tubing. The inner sleeve may be movable by means of a remotely operated tool driven by an electric or hydraulic motor, e. g. via coiled tubing or electrical cables, or the inner sleeve may be movable by a drill string. In both cases the motion may be transferred to the inner sleeve via a gripping tool having electrically or hydraulically activated clamping bars. The movability of the inner sleeve can also be realized by devices integrated in the sleeve valve, e. g. hydraulic cylinders. In addition to the inner sleeve being movable between positions in which openings of the two sleeves register or do not register, the inner sleeve may also be movable to intermediate positions, enabling the fluid flow to be adjusted to intermediate positions between closed and fully open flow.

The invention will now be explained in more detail in connection with descriptions of particular embodiments, and with reference to the drawing, in which: Fig. 1 illustrates a sleeve valve according to the invention in a hydrocarbon reservoir, Fig. 2 illustrates the sleeve valve in fig. 1 with a portion of the inner sleeve and the outer sleeve cut away, Fig. 3 illustrates an enlarged segment of fig. 2, Fig. 4 illustrates a cross section through the sleeve valve, taken along the section line IV-IV in fig. 1, in which the inner sleeve is in injection position, Fig. 5 illustrates a cross section through the sleeve valve, taken along the section line IV-IV in fig. 1, in which the inner sleeve is in open position, and

Fig. 6 illustrates a cross section through the sleeve valve, taken along the section line IV-IV in fig. 1, in which the inner sleeve is in closed position.

Fig. 1 illustrates a sleeve valve 1 according to the invention in a well 4 in a hydrocarbon reservoir 2. The sleeve valve 1 comprises an outer sleeve 5 with openings 7. In each end the outer sleeve 5 has a threaded portion 27 which is screwed into the ends of two sections of a production tubing 3, one of them being illustrated in a cross section. The sleeve valve 1 is thereby integrated in the production tubing 3. The production tubing 3 with the sleeve valve 1 has been moved through a not illustrated casing in the well 4, through a not illustrated packer in the end of the casing, and into the reservoir 2. During the production of hydrocarbons, the hydrocarbons will flow from the reservoir 2 and into the openings 7 in the outer sleeve. In order to prevent hydrocarbons from flowing along the outside of the sleeve valve 1 and the production tubing 3, the space between the sleeve valve 1 and the well wall 21 has been filled with concrete 11, which has been pumped down through the production tubing 3, and forced up on the outside of the production tubing 3 and the sleeve valve 1.

A centraliser 28, which is a part of the sleeve valve 1, ensures that on all sides of the sleeve valve there is a certain distance to the well wall 21, the concrete 11 thereby completely fills the space between the sleeve valve 1 and the well wall 21.

In addition to preventing flow of hydrocarbons along the sleeve valve, the concrete 11 also prevents inflow of hydrocarbons to the sleeve valve. In the following, it will be explained how an open area between the openings 7 in the outer sleeve and the well wall 21 is established by means of the sleeve valve 1 according to the invention, allowing hydrocarbons to flow into the sleeve valve 1 from the reservoir 2.

Fig. 2 illustrates the sleeve valve 1 in fig. 1 with a portion of the outer sleeve 5 cut away, while fig. 3 illustrates an enlarged segment of fig. 2. An inner sleeve 6, also shown partly cut away, is provided with openings 8. It is seen that the inner sleeve 6 is much shorter than the outer sleeve 5, and extend approximately from the centraliser 28 on one of the sides of the openings 7 in the outer sleeve, past the openings 7 in the outer sleeve, to approximately halfway between the openings 7 in the outer sleeve and the place where the outer sleeve 5 is provided with chambers 9, which will be discussed in more detail later.

The illustrated sleeve valve is a rotational sleeve valve, in which the inner sleeve 6 by means of an actuator or a tool is rotatable between an open position in which the openings 8 in the inner sleeve register with the openings 7 in the outer sleeve, and fluids can flow between the exterior of the outer sleeve 5 and the interior of the inner sleeve 6, and a closed position in which the openings 8 of the inner sleeve do

not register with the openings 7 of the outer sleeve, and fluid flow is prevented.

The inner sleeve 6 may also be rotatable to intermediate positions, in which the fluid flow is between full inflow and no inflow. The interior of the inner sleeve 6 is in communication with the production tubing 3, and the sleeve valve can thereby be used for controlling fluid flow between the hydrocarbon reservoir 2 and the production tubing 3. The rotation of the inner sleeve can be carried out by an electric or hydraulic actuator or by a tool, e. g. by means of a drill string, which by means of gripping means engages and rotates the inner sleeve.

The sleeve valve according to the invention comprises at least one chamber 9 for concrete-curing inhibitor, and at least one passage from the chamber 9 for concrete-curing inhibitor to at least one injection outlet 10 on the outside of the inner sleeve 6. The injection outlet 10 registers with the opening 7 of the outer sleeve when the inner sleeve 6 has been moved to a particular position, designated the injection position. In the illustrated embodiment several injection outlets 10 are used, each injection outlet 10 registers with a corresponding opening 7 in the outer sleeve 5.

The at least one chamber 9 for concrete-curing inhibitor is realized by several elongated chambers 9 (only two can be seen in fig. 2 and 3) for concrete-curing inhibitor, located in the outer sleeve 5. The chambers 9 extend in the longitudinal direction of the sleeve valve 1, and are located beside each other along the circumference of the outer sleeve 5.

The at least one passage from the chamber 9 for concrete-curing inhibitor to the injection outlet 10 is realized by channels 12,12'in the outer sleeve 5 and channels 14 in the inner sleeve 6. The channels 12,12'in the outer sleeve have outlets 13 on the inside of the outer sleeve 5, while the channels 14 in the inner sleeve have inlets 15 on the outside of the inner sleeve 6. The outlets 13 from the channels 12, 12'in the outer sleeve and the inlets 15 to the channels 14 in the inner sleeve are positioned in such a way that they register when the inner sleeve 6 is located in the injection position. 0-rings 29 prevent leakage from the outlets 13 of the channels in the outer sleeve and the inlets 15 of the channels in the inner sleeve.

The sleeve valve 1 further comprises at least one actuator for ejecting concrete- curing inhibitor from the chambers 9, through the channels 12,12', 14, the injection outlets 10 and the openings 7 in the outer sleeve, for injecting concrete- curing inhibitor into uncured concrete 11 outside the outer sleeve 5. In the illustrated embodiment the actuator is realized by each chamber 9 being provided with a piston 16, which is secured to a common actuator for simultaneous ejecting concrete-curing inhibitor from all the chambers 9. The common actuator is formed by an annular piston 17 which is movable in an annular cylinder 18, and which via

piston rods 31 is connected to the pistons 16.0-rings 30 prevent leakage past the annular piston 17 in the annular cylinder 18.

The annular cylinder 18 is provided with an inlet 19 which is open towards the inside of the sleeve valve, i. e. the inside of the outer sleeve 5, for pressurizing the annular cylinder 18 with a pressure in the interior of the sleeve valve. Alternatively the inlet 19 could have been open towards the outside of the sleeve valve, i. e. the outside of the outer sleeve, for pressurizing the annular cylinder with a pressure on the outside of the sleeve valve. The annular piston 17 is in a retracted position secured in the annular cylinder 18 by a shear pin 20, which is adapted to break and release the annular piston 17 at a predetermined pressure in the annular cylinder 18.

The concrete-curing inhibitor must be injected in the concrete after the concrete during the cementing has settled, but before the concrete cures. The concrete- curing inhibitor may e. g. be a hydrocarbon, but other concrete-curing inhibitors may also be used. Before the injection of concrete-curing inhibitor, it is ensured that the inner sleeve 6 has been rotated to the injection position. The injection of concrete-curing inhibitor in the concrete 11 is carried out by pressurizing the interior or exterior of the sleeve valve, which can be controlled from the surface, either by means of coiled tubing or by pressurizing the well. The pressure propagates through the inlet 19 to the annular cylinder 18, and when the pressure exceeds the pressure which is required to break the shear pin 20, the shear pin is broken, and the annular piston 17 moves into the annular cylinder 18. The movement of the annular piston is via the piston rods 31 transferred to the pistons 16, which force concrete-curing inhibitor out of the chambers 9, through the channels 12,12'and 14 and out through the injection outlets 10 which are located in the openings 7 in the outer sleeve.

The chambers 9 for concrete-curing inhibitor and the injection outlets 10 are preferably via the channels 12,12', 14 interconnected in a one to one configuration.

It is thereby ensured that the same amount of concrete-curing inhibitor, i. e. the content in one chamber 9, is injected in the concrete from each injection outlet 10.

The annular cylinder 18 is formed by a cylindrical cavity extending along the circumference of the outer sleeve 5, while the chambers 9 are formed by cylindrical bores which have been drilled in the longitudinal direction of the outer sleeve, and which extend from the bottom of the annular cylinder 18 and further into the outer sleeve. The channels 12 of the outer sleeve are formed by bores which have been drilled in extension of the chambers 9, while radially drilled bores form transverse channels 12'extending from the channels 12 to the outlets 13. The channels 14 of the inner sleeve are formed by bores which have been drilled in the longitudinal

direction of the inner sleeve 6, while radially drilled bores form the inlets 15 and the injection outlets 10.

Fig. 4 illustrates a cross section through the sleeve valve 1, taken along the section line IV-IV in fig. 1. The openings 7 of the outer sleeve 5 are provided with sealing elements 26 with through openings 24 for the fluid flow. The sealing elements have sealing surfaces 25 which abut the outside of the inner sleeve 6. It can be seen that the channels 14 of the inner sleeve have their outlets in the injection outlets 10.

The inner sleeve 6 is located in the injection position, and the injection outlets 10 register with the openings 7 of the outer sleeve, or strictly speaking the openings 24 of the sealing element. When injecting concrete-curing inhibitor in the concrete 11, as discussed above, flows 33 of concrete-curing inhibitor flow out through the injection outlets 10, out through the openings 7 of the outer sleeve (strictly speaking the openings 24 of the sealing element) and into the concrete 11. Here the concrete-curing inhibitor is mixed with the concrete 11 in areas 22 between the openings 7 in the outer sleeve and the well wall 21. After some time the concrete cures around the areas 22, while the concrete in the areas 22 remain uncured.

After the concrete around the areas 22 has cured, the inner sleeve 6 is rotated in direction 23, until the inner sleeve reach open position, which is illustrated in fig.

5. The openings 8 of the inner sleeve now register with the openings 7 of the outer sleeve (strictly speaking the openings 24 of the sealing element). The pressure in the sleeve valve is then lowered, which is done by opening a valve which let out fluids from the well at the surface. The reservoir is under pressure, and a fluid flow 34 of hydrocarbons is formed, from the reservoir 2 to the openings 7 in the outer sleeve, through the openings 24 of the sealing element, through the openings 8 in the inner sleeve, into the interior of the inner sleeve 6, and into the production tubing 3. The fluid flow 34 flushes away the uncured concrete from the areas 22, and the sleeve valve is now fully installed.

The inner sleeve 6 can now be moved to desired positions, e. g. closed position, which is illustrated in fig. 6, in which the openings 8 in the inner sleeve and the openings 7 in the outer sleeve (strictly speaking the openings 24 of the sealing element) do not register, or an intermediate position between open and closed position, as discussed above.

The injection position of the sleeve valve, see fig. 4, may be identical to the closed position of the sleeve valve, see fig. 6. In this case the injection outlets 10 can be positioned halfway between the openings 8 of the inner sleeve. Further the inner sleeve and the outer sleeve may be provided with corresponding, not illustrated stops, located in such a way that the open position is located in one end of a rotational area for the inner sleeve 6, while the combined injection position and

closed position is located in the other end of the rotational area. A simple way of operating the inner sleeve is thereby achieved.

In the method for providing a controllable fluid flow 34 between a hydrocarbon reservoir 2 and a production tubing 3 in a well 4 in the hydrocarbon reservoir 2 according to the invention, a sleeve valve 1 according to the invention is used. The method comprises the following steps: a) integrating the sleeve valve 1 in a production tubing 3, and placing the production tubing in the well 4 in the hydrocarbon reservoir 2, in a per se known way, the sleeve valve's chamber 9 for concrete-curing inhibitor is filled with concrete-curing inhibitor, and the inner sleeve 6 is located in an injection position, see fig. 4, b) filling the space between the production tubing 3 with the sleeve valve 1 and the well wall 21 with liquid uncured concrete 11, c) activating the actuator 17 for ejecting concrete-curing inhibitor from the chamber 9, causing the concrete-curing inhibitor to be injected in the concrete 11 and form open areas 22 which allow fluid flow 34 between the reservoir 2 and the opening 7 in the outer sleeve, and d) moving the inner sleeve 6 to open position, see fig. 5, for establishing an initial fluid flow 34 between the reservoir 2 and the opening 7 in the outer sleeve, whereupon the inner sleeve 6 can be moved to a desired position, for establishing a desired fluid flow 34.

For a detailed explanation of the different steps which are included in the method according to the invention, reference is made to the above description of the sleeve valve according to the invention.