COMPLETION ARRANGEMENT
A completion arrangement and methods of using the completion arrangement are described herein. The completion section includes a completion section and impacting formations. The completion section is arranged to be coupled to production tubing, and has means to allow hydrocarbons to pass therein from reservoir rock in which the wellbore is formed. The impacting formations are drivingly moveable relative to the wellbore. The means being arranged to serve as flushing portals, whereby drilling fluid introduced into the production tubing is arranged to flow via the means into a space between the production tubing and the wellbore, and circulate in the space and the impacting formations. One, or both, of the drilling fluid circulating in the space and the impacting formations are arranged to remove obstructing material and formations from the wellbore for return to surface by way of the space, during insertion of the completion arrangement into the wellbore.
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1. Field of the Invention
The present invention relates to a completion arrangement. More particularly, to a completion arrangement for a hydrocarbon and/or an injection well.
2. Description of the Relevant Art
When an oil/gas well is drilled, extraction equipment is inserted into an oil/gas reservoir from which oil/gas will be produced to the surface. A bore is drilled into the oil/gas reservoir and production tubing is introduced into the bore. The oil/gas well has then to be “completed”, which entails running a completion section into the well to enable extraction of hydrocarbons from the reservoir for transfer to the surface via the production tubing. It is generally desired that the completion section is ideally located at, or extends into, the bottom (or total depth) of the well.
A number of “completion” devices exist, for example, “openhole completions”, i.e. where a packer is provided on tubing above an “openhole” (an openhole being an uncased portion of a wellbore), or “inflow control devices”, i.e. a tubing section provided with devices to control flow of fluid from the reservoir to the interior of the tubing section in a producing well and control flow of fluid from the tubing section to the reservoir in an injection well.
In current completion techniques, when the completion is “run-in” to the well, it is the weight of the completion string that urges the completion to the end of the well.
However, such techniques are problematic in that the completion may get stuck due to entrained rock and debris accumulated at the head of the completion. Additionally, there may be “burrs” in the openhole section of the well caused by the drilling process, and the completion may also become stuck when it encounters these “burrs”.
Under the current techniques, if the completion becomes stuck as described above, then remedial actions (such as “jarring” the completion string) are taken to free the completion in an attempt to insert the completion section further into the wellbore. Unfortunately, these remedial actions are not always successful, which leads to the well being completed as is or side-tracked. The problem of the completion becoming stuck is a particular problem in long horizontal wells.
WO 2008/043985 describes drilling a lower completion into a pre-drilled wellbore with casing liner. A casing liner is a tubular section that conventionally is ‘pushed’ into the pre-drilled hole to total depth. Once to total depth, the casing liner is cemented into place by pumping cement into the space between the reservoir rock and the casing liner (tubular section). The cement is required for structural integrity and to hold the casing liner in place. In order for hydrocarbons to reach the production tubing to flow to the surface, it is necessary that the casing liner be perforated using perforating charges to connect the production tubing space to the reservoir rock.
The present invention seeks to provide for a completion arrangement having advantages over known such completions.
SUMMARYIn one embodiment, there is provided a completion arrangement for a hydrocarbon wellbore including: a completion section arranged to be coupled to production tubing, and having means to allow hydrocarbons to pass therein from reservoir rock in which the wellbore is formed, the means also arranged to serve as flushing portals, whereby drilling fluid introduced into the production tubing is arranged to flow via the means into a space between the production tubing and the wellbore and circulate in the space; the arrangement further including impacting formations, drivingly moveable relative to the wellbore, wherein one, or both, of the drilling fluid circulating in the space and the impacting formations are arranged to remove obstructing material and formations from the wellbore, for return to surface by way of the space, during insertion of the completion arrangement into the wellbore.
An advantage of the present invention is that debris around the completion arrangement during an insertion process can be removed by: (i) flushing drilling fluid through the means which, during production, are arranged to allow hydrocarbons to pass into the production tubing from reservoir rock in which the wellbore is formed, but which, during the insertion process, allow drilling fluid to enter a space around the production tubing; and (ii) driving the impacting formations. Thus, with the above two features, the completion section is less likely to become stuck when being “run-in” to the well.
In one embodiment, the lower completion can be set into the openhole section without cementing. Once the well is put into production, the hydrocarbon from the reservoir rock is drawn into the space created by the openhole packers. The hydrocarbon then flows from the space, through nozzles in the flow restrictors into the production tubing and then on to the surface. If this particular arrangement was to be cemented, then connection between the production tubing and the reservoir will be required via perforating charges. However, in an embodiment, cementing is not required and the stability of the openhole section is maintained by the strength of the reservoir rock.
In an embodiment, cementing is not required since the type of lower completion serves a different purpose—this is an openhole completion with openhole packers and flow restrictors.
The invention is further advantageous in that it enhances completion deployment and allows longer completions to be run, thereby providing completion capabilities for extended reach applications.
The impacting formations are operable to crush, cut, abrade, scrape, pound or grind material and formations in the wellbore.
In an embodiment, the means to allow hydrocarbons to pass therein from reservoir rock in which the wellbore is formed may include flow restrictors having at least one nozzle.
In one embodiment, impacting formations include a drill bit or ream-in shoe.
Conveniently, the impacting formations are operable by rotating the production tubing, to which the impacting formations are coupled via the completion section.
In an embodiment, the completion arrangement includes a motor coupled between the completion section and the impacting formations and arranged to control operation of the impacting formations.
The motor includes a mud motor operable by means of drilling fluid supplied thereto through the production tubing and completion section.
In one embodiment, drilling fluid further serves to lubricate the impacting formations.
In one embodiment, there is provided production tubing for a hydrocarbon well that includes a completion arrangement as described above.
In one embodiment, method of completing a hydrocarbon wellbore, includes inserting a completion arrangement into the wellbore, the completion arrangement including a completion section having means for allowing hydrocarbons to pass therein from reservoir rock in which the wellbore is formed and impacting formations, and the means also arranged to serve as flushing portals whereby drilling fluid introduced into completion section via production tubing is arranged to flow via the means into a space between the completion arrangement and the wellbore and circulate in the space ; and introducing drilling fluid into the completion arrangement for flow via the means into the space and/or driving the impacting formations so as to move relative to the wellbore to remove obstructing material and formations from the wellbore during insertion of the completion arrangement into the wellbore.
In one embodiment, driving includes rotating the production tubing to drive the impacting formations.
In one embodiment, the method includes locating a motor between the completion section and the impacting formations, and driving includes activating the motor by means of fluid pumped to the motor via production tubing coupled to the completion section such that the motor can operate the impacting formations.
The present invention is described further hereinafter, by way of example only, with reference to the accompanying drawings.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawing and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
DETAILED DESCRIPTIONIn addition to the production tubing 22 and the completion section 26, the illustrated embodiment of the completion arrangement of the invention includes a drill bit 28 coupled to an end of the completion section 26 remote from the end coupled to the production tubing 22. The drill bit 28 is located at the “front” face of the completion section 26, i.e. the face of the completion section 26 which is foremost with respect to its direction of travel into the openhole section 20.
The illustration of
The completion section 26 preferably includes a number of different combinations of extraction devices, valves, sensors, measurements, mechanical and swellable packers etc. In a particular arrangement as illustrated in
The illustrations of
Turning now to
Here, the completion section 26 and drill bit 28 have reached total depth, i.e. the maximum extent to which the bore has previously been drilled. Once the completion section 26 and drill bit 28 have reached the total depth, the well 10 is effectively “complete” and an oil/gas extraction process can commence without limitation that might occur due to incomplete insertion of the production tubing and completion section.
The lubrication process has been described above. Now the operation of the drill bit 28 found in the illustrated embodiments of the invention will now be described in more detail.
As described above, in conventional processes where an oil/gas well is “completed”, the extraction equipment (including a completion section) is introduced into the wellbore, and it is the weight of the completion section and production tubing that urges the completion towards the end of the well (i.e. total depth) and pulls the production tubing behind it. However, and as mentioned above, the presence of “burrs” on the walls of the openhole section of the well which were introduced by the drilling process, or the accumulation of debris in front of the completion section, may cause the completion section to become stuck. Remedial actions (e.g. “jarring”) are possible which can free the completion section for further insertion into the wellbore, but these are not always effective and the well may therefore have to be completed without the completion section reaching total depth.
By providing a drill bit 28 at the head of the completion section 26, this allows the completion section 26 to be drilled, or rather reamed into position in the wellbore should the lubrication process fail at some point to ease passage of the completion section into the well. Thus, in the illustrations of
In a preferable arrangement, the drill bit 28 is rotated by rotating the production tubing 22 at the surface 14 when the drill bit 28 has reached a pre-detemined depth (e.g. when it has entered the openhole section 20). By activating the drill bit, the openhole section 20 is drilled/reamed and this allows the completion section 26 to reach total depth without becoming stuck.
Another arrangement of the present invention is illustrated in
The mud motor 30 is arranged to drive and control operation of the drill bit 28 and eliminates the requirement to rotate the production tubing 22 at surface 14 to operate the drill bit 28.
It should be appreciated that the drill bit 28 and/or the motor 30 is intended to remain in place once its final depth has been reached.
The mud motor 30 operates by means of fluid pumped from the surface through the production tubing 22 (denoted by arrows A). This fluid activates the mud motor 30 which, in turn, operates the drill bit 28. The drill bit 28 preferably includes a number of nozzles 32 to allow the drilling fluid to exit a face of the drill bit 28. After the drilling fluid has exited through the nozzles 32, and through nozzles 206 in the flow restrictor 200, it can lubricate the drill bit 28 and carry the debris from the face of the drill bit 28 back through the space between the production tubing 22 and the walls of the openhole section 20 and between the production tubing 22 and the production casing 28 to the surface 14 (this is indicated by arrows B).
Advantages of the present invention have been described above although the present invention is particularly advantageous when used in the completion of horizontal wells.
Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
Claims
1. A completion arrangement for a hydrocarbon wellbore, comprising:
- a completion section arranged to be coupled to production tubing, and having means to allow hydrocarbons to pass therein from reservoir rock in which the wellbore is formed, the means also arranged to serve as flushing portals, whereby drilling fluid introduced into the production tubing is arranged to flow via the means into a space between the production tubing and the wellbore and circulate in the space; and
- impacting formations, drivingly moveable relative to the wellbore, wherein one, or both, of the drilling fluid circulating in the space and impacting formations are arranged to remove obstructing material and formations from the wellbore, for return to surface by way of the space, during insertion of the completion arrangement into the wellbore.
2. The completion arrangement of claim 1, wherein the means to allow hydrocarbons to pass therein from reservoir rock in which the wellbore is formed comprise flow restrictors having at least one nozzle.
3. The completion arrangement of claim 1, wherein the impacting formations comprise a drill bit and/or a ream-in shoe.
4. The completion arrangement of claim 1, wherein the impacting formations are operable by rotating the production tubing, to which the impacting formations are coupled via the completion section.
5. The completion arrangement of claim 1, further comprising a motor coupled between the completion section and impacting formations, and arranged to control operation of the impacting formations.
6. The completion arrangement of claim 5, wherein the motor comprises a mud motor operable by means of drilling fluid supplied thereto through the production tubing and completion section.
7. The completion arrangement of claim 1, wherein the drilling fluid further serves to lubricate the impacting formations.
8. Production tubing for a hydrocarbon well, comprising:
- a completion arrangement comprising: a completion section coupled to the production tubing, and having means to allow hydrocarbons to pass therein from reservoir rock in which the well bore is formed, the means also arranged to serve as flushing portals, wherein drilling fluid introduced into the production tubing is arranged to flow via the means into a space between the production tubing and the wellbore and circulate in the space; and impacting formations, drivingly moveable relative to the well bore, wherein one, or both, of the drilling fluid circulating in the space and the impacting formations are arranged to remove obstructing material and formations from the well bore, for return to surface by way of the space, during insertion of the completion arrangement into the well bore.
9. A method of completing a hydrocarbon wellbore, comprising,
- inserting a completion arrangement into the wellbore, the completion arrangement comprising: a completion section having means for allowing hydrocarbons to pass therein from reservoir rock in which the wellbore is formed, and the means being arranged to serve as flushing portals whereby drilling fluid introduced into completion section via production tubing is arranged to flow via the means into a space between the completion arrangement and the wellbore and circulate in the space; and impacting formations; and
- introducing drilling fluid into the completion arrangement for flow via the means into the space; and/or
- driving the impacting formations so as to move relative to the wellbore to remove obstructing material and formations from the wellbore during insertion of the completion arrangement into the wellbore.
10. The method of claim 9, wherein the driving comprises rotating the production tubing to drive the impacting formations.
11. The method of claim 9, further comprising locating a motor, between the completion section and the impacting formations, and wherein the driving step comprises activating the motor by means of fluid pumped to the motor via production tubing coupled to the completion section such that the motor can operate the impacting formations.
Type: Application
Filed: Nov 6, 2008
Publication Date: Sep 6, 2012
Applicant:
Inventors: Sam Simonian (Manama), Colin Boyle (Hertfordshire), Neale Carter (Hertfordshire)
Application Number: 12/744,462
International Classification: E21B 21/00 (20060101); E21B 4/00 (20060101); E21B 10/26 (20060101);