The present invention relates to an assembly to be run with a well tubular having openings provided in the wall and for being arranged in a well bore and thereby forming a space between said tubing and the well bore surface, said assembly comprising; first fluid control means being provided in one opening in said well tubular; second fluid control means being provided in another opening in said well tubular and; a set of packers for sealing off the space between said tubing and the well bore surface, said set of packers being positioned such that a part of the tubular having both first and second fluid control means is located between the set of packers. Thereby the packers divide the spacing between the well bore and the tubing into separate sections.
The present description includes both a drilled well intended for injection of water into the formation with a view to displacing oil or gas in a direction towards a drilled production well or it may be a drilled production well intended for production of oil or gas.
Before the injection of water into the formation can be initiated, it is necessary to stimulate a well bore by pumping down acid that decomposes the compacted layer of drilling mud on the wall of the well bore and a part of the formation. The acid is conveyed into the well bore by means of a supply pipe with a nozzle head that is, while acid is being pumped down, withdrawn slowly from the bottom of the well bore. The described process is labour-intensive, costly and delays the time of onset of production.
The invention aims to remedy the problems and limitations that are associated with conventional techniques for stimulating a drilled well and to provide a new assembly, wherein the invention enables subsequent control of the stimulated well. The system will allow for stimulation and zonal isolation (or segmenting the reservoir), in a quick and efficient manner.
The object of the invention is obtained by an assembly where the first fluid control means is adapted such that it is capable of blocking fluid flow from the interior of said well tubular to said space between said tubing and the well bore surface and that the second fluid control means is adapted such that it is capable of blocking fluid flow from said space between said tubing and the well bore surface to the interior of said well tubular, said second fluid control means comprise a valve equipped with a self-closing mechanism which is capable of completely closing off the valves, said self-closing mechanism being adapted such that acid stimulation may take place through the second fluid control means while in their open state.
By using valves equipped with a (self-closing) mechanism capable of completely closing off the valves, e.g. after a certain time delay, it is accomplished that “injector wells” can be stimulated via the second fluid control means with acid prior to being used. When the second fluid control means are subsequently closed, the subsequent injection of water will take place via the first fluid control means in the individual sections of the well (between two packers) and thereby an increased control of that type of well is also accomplished since the individual sections can thereby be closed down by means of the first fluid control means.
These openings equipped with second fluid control means can e.g. be distributed as described in European patent application NO EP1184537A.
In one embodiment of the invention the first fluid control means comprises a sliding sleeve door (ssd) arranged on the tubular. The sliding sleeve door comprises an aperture in the tubular through which the oil or gas will enter the tubing. The sliding sleeve door can be closed or opened during operation of the well. Sliding sleeve doors are well known to the person skilled in the art and there functionality will therefore not be described in greater details.
In another embodiment screens for the removing of sand particles from the fluid of oil and gas are arranged on the outside of the sliding sleeve door. Such a screen can be manufactured from the material Boron Carbide, which offers the advantage that it can only be eroded by pure diamonds. Furthermore, Boron Carbide ceramic material has a good resistance against acids, such that cleaning of the filter can be done by an acid treatment.
In another embodiment the second fluid control means comprise a check valve, which will allow fluid to flow from the interior of said well tubular to said space between the tubular and the well bore. By use of check valve the stimulation treatment can flow out and into the formation through the non-return valves, while production flow can enter the tubular through the first fluid control means.
Other embodiment of the invention are recited in the independent claims
Methods of use of the assembly are recited in claims 10-11.
The invention will now be described in further detail with reference to the preferred embodiments shown in the drawings.
In conventional tubing openings 3 are regular holes which allows fluid flow to run both from the interior of the tubing 12 and to annular space 5 and from the annular space to the interior of the tubing. The reason behind having these openings is to facilitate the stimulation of the wellbore. The openings 3 can have a location that comply with particular, pre-defined specifications, as e.g. described in patent application NO EP 1184537A
In the assembly according to the invention these openings are provided with fluid control means (not shown in
Opening or closing of a “sliding sleeve” is normally achieved by use of known intervention tools run on a wireline or a coiled tubing. However the opening and closing of the opening 6 can be achieved in many other ways known to the person skilled in the art and the activation of the first fluid control means can even be made such that it is controllable from the surface.
The packers 10, 11 are positioned such that a part the tubular having both first 4 and second fluid control means 3 is located between the set of packers 10, 11. Normally, the first fluid control means is adapted such that it is capable of selectively opening or blocking fluid flow from the interior of said well tubular to said space 5 between the formation and the well tubular 2 and the second fluid control means is adapted such that it is capable of either allowing or blocking fluid flow both from said space to the interior of said well tubular and from the interior of said well tubular to said space 5 between the formation and the well tubular 2. In one embodiment of the invention is the second fluid control means adapted such that it is capable to first allow fluid flow in both direction and thereafter to close off fluid direction in both directions. This can e.g. be accomplished by use of valves equipped with a self-closing mechanism which keeps the valves open until it is triggered to close by a time delay mechanism.
By using valves equipped with a (e.g. self-closing) mechanism which is capable of completely closing off the valves, it is accomplished that “injector wells” can be stimulated via the second fluid control means with acid prior to being used. When the second fluid control means are subsequently closed, the subsequent injection of water will take place via the first fluid control means in the individual sections of the well (between two packers) and thereby an increased control of that type of well is also accomplished since the individual sections can thereby be closed down by means of the first fluid control means.
By establishing of several independent assemblies having both first and second fluid control means in a well as described above it is thus possible to stimulate and open up or close off production from selected parts of the well. Opening and/or closing off such a part is normally done on order to isolate e.g. a water producing part of the well to ingress of water, or to delimit a part of the well.
As described above the second fluid control means may be equipped with a closure mechanism that does not close until a given period of time has elapsed. However, the second fluid control means may also be equipped with a closure mechanism that does not close until the closure mechanism is activated by some kind of activation means, as e.g described below. Thereby it is obtained that (when the well is a recently established one) acid stimulation may take place through the second fluid control means while in their open state.
In one embodiment of the invention the assembly comprises an inflatable packer section or a “mechanical” packer that does not rely on inflation with fluids. Such packers are known in the industry and comprises e.g. packers that needs to be triggered with a timer and then it sets by squeezing a steel enforced rubber membrane that then creates the seal.
The inflatable packer section might be equipped with one or more packers which can be inflated by fluid. Such inflatable packers are well known to the person skilled in the art and normally they may be used on the outside of a well tubular. In order to control the inflation (or deflation) of the inflatable packer section the section is normally provided with one or more valves for opening and closing of fluid communication into (or out of) the inflatable packer section.
The energy required for delivering of fluid into the inflatable packer section might be delivered by any suitable energy source, as e.g. one or more batteries contained in an energy section. In order to control the expanding of the inflatable packers the assembly might further comprises a triggering section 7. The triggering section 7 is capable of controlling the energy source and/or controlling of the valve means and, therefore, the triggering section 7 is capable of controlling the delivery of fluid into the inflatable packer section. However, as known to the skilled person, the triggering section 7 can also be capable of controlling the expansion of mechanical packers.
The triggering section 7 is thus performs a “trigger/detect function” that is capable of controlling the flow of inflation fluid to the packer. It will either release the flow of fluid by opening of valve(s) to the packer. Or it will turn on e.g. an electrical pump that will transfer the fluid into the packer. The triggering section 7 could also be adapted to control a mechanical packer.
In one embodiment of the invention the triggering section 7 is also capable of controlling the opening and/or closing of the first fluid control means. The triggering system can be activated either by a timing mechanism, RFID detection, seismic, or other kinds of sonic, optical or electric signal.
One method of use of an embodiment of the invention will now be described.
Turning to
After stimulating of the well is at least two packers expanded in order to seal off a part of said annular space. However, to e.g. protect a well segment from stimulation the packers could also be expanded prior to pumping of acid. If the packers are expanded after the pumping of acid is this step normally followed by the step of closing the second fluid control means. However, the step of closing the second fluid control means could also be conducted after the stimulation but prior to the expansion of the packers.
As described above, acid stimulation of the well takes place through the second fluid control means. During this process, the first fluid control means are usually closed. It is therefore necessary to subsequently open the first fluid control means in order to allow water to run into the formation.
The closing of the second fluid control means can be accomplished by use of e.g. by “an acid-activated valve” as described below.
In injection wells, a special non-return valve will be installed with an “acid detection” mechanism or a “delayed closing” mechanism. The mechanism is that the valve will have some of its components made of a material that is acid solvable (e.g. zinc, aluminium etc.). This acid solvable material is used to protect a “hold-open” mechanism. Once the stimulation job is performed, this hold-open mechanism is dissolved, and the non-return valve will shut off flow from both directions, effectively turning into a plug.
This will facilitate that subsequent injection is directed through the opening sleeves (first fluid control means) and not through the second fluid control means (second fluid control means) inserts.
A delayed closing valve 200 can also be made with a water swellable elastomer compound 205 that slowly swells during injection of water and thereby slowly closes the valve 200, permanently. (See
Another embodiment of a closing valve is illustrated in
In
The valve is, in the shown embodiment, operated by a spring 39 and a pin 35 but other types of actuation means known to the skilled man may be used (even electric 255 or hydraulic actuators) may be used to actuate a valve 250. (See
When the stimulation fluid is pumped through the valve, a small “weep-hole” 37 flow path ensures that the acid soluble pin 35 is emerged in a continuous flow of acid, which then weakens (or totally dissolves) the tip of the pin. While a pressure differential is present across the well tubular (i.e. fluids are being pumped through the valve), the shuttle valve will remain open due to the force acting on the left side of the gate 32 and exerting against the spring.
Once pumping stops and there is not pressure differential across the well tubular, the spring will force the gate towards the left (in the shown embodiment) until the solid part of the gate 32 (shown in
In that position is the valve balanced, and cannot be re-opened by applying a pressure differential across the well tubular.” A simple lock ring 38 can be intersected that will effectively lock the valve in the closed position.
Number | Date | Country | Kind |
---|---|---|---|
2009 00764 | Jun 2009 | DK | national |
This application claims the benefit under 35 U.S.C. §371 of International Patent Application No. PCT/EP2010/058793, having an international filing date of Jun. 22, 2010, which claims priority to Danish Patent Application No. PA 2009 00764, filed Jun. 22, 2009, and U.S. Provisional Application No. 61/219,193, filed Jun. 22, 2009, the contents of all of which are incorporated herein by reference in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2010/058793 | 6/22/2010 | WO | 00 | 3/13/2012 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2010/149644 | 12/29/2010 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
2832415 | Reistle, Jr. | Apr 1958 | A |
2897897 | Breukelman | Aug 1959 | A |
3252904 | Carpenter | May 1966 | A |
3586018 | Bogardh et al. | Jun 1971 | A |
4949788 | Szarka | Aug 1990 | A |
5441929 | Walker | Aug 1995 | A |
6481500 | Burd | Nov 2002 | B1 |
6915848 | Thomeer et al. | Jul 2005 | B2 |
7066265 | Surjaatmadja | Jun 2006 | B2 |
7604055 | Richard et al. | Oct 2009 | B2 |
7828067 | Scott et al. | Nov 2010 | B2 |
7967071 | Brown | Jun 2011 | B2 |
20010018977 | Kilgore | Sep 2001 | A1 |
20020153142 | Eslinger | Oct 2002 | A1 |
20030188871 | Dusterhoft | Oct 2003 | A1 |
20050061508 | Surjaatmadja | Mar 2005 | A1 |
20050103495 | Corbett | May 2005 | A1 |
20060042795 | Richards | Mar 2006 | A1 |
20080283238 | Richards | Nov 2008 | A1 |
20080283252 | Guignard | Nov 2008 | A1 |
20090090502 | Lumbye | Apr 2009 | A1 |
20090101352 | Coronado et al. | Apr 2009 | A1 |
Number | Date | Country |
---|---|---|
1184537 | Mar 2002 | EP |
2394736 | May 2004 | GB |
WO 0165060 | Sep 2001 | WO |
2004099560 | Nov 2004 | WO |
WO2008139132 | Nov 2008 | WO |
Entry |
---|
Search Report for PA 2009 00764, Feb. 1, 2010. |
International-Type Search Report for DK 200900764, Feb. 18, 2010. |
International Search Report for PCT/EP2010/058793, Dec. 29, 2010. |
Written Opinion of the International Search Authority for PCT/EP2010/058793, Dec. 22, 2011. |
International Preliminary Report on Patentability for PCT/EP2010/058793, Mar. 1, 2012. |
Search Report for PA 2009 00765, dated Feb. 1, 2010. |
International-Type Search Report for DK 200900765, dated Feb. 18, 2010. |
International Search Report for PCT/EP2010/058792, dated Aug. 26, 2010. |
Written Opinion of the International Search Authority for PCT/EP2010/058792, dated Aug. 26, 2010. |
International Preliminary Patentability Report for PCT/EP2010/058792, dated Jan. 4, 2012. |
Number | Date | Country | |
---|---|---|---|
20120160520 A1 | Jun 2012 | US |
Number | Date | Country | |
---|---|---|---|
61219193 | Jun 2009 | US |