CONCENTRIC COIL TUBING DEPLOYMENT FOR HYDRAULIC FRACTURE APPLICATION
A method and system for treating a portion of a wellbore. The system includes a coiled tubing string having two fluid flow areas and a valve configured to control the fluid flow out of both flow areas. The system may include at least one isolation element used to isolate a portion of a wellbore. The isolated portion of the wellbore may be treated by pumping fluid down one or both of the flow areas. The valve may be actuated to permit fluid to be pumped down one flow area while fluid is pumped up the other flow area, which may be used to clean out a screen out, treatment, proppant, and/or solids in the wellbore. The coiled tubing string with two fluid flow areas may be used to treat, stimulate, and/or fracture a portion of a wellbore and provide cleanout capabilities, if required.
This disclosure relates to coiled-in-coiled tubing. More particularly, this disclosure relates to systems and methods for concentric coiled-in-coiled tubing for use in treating a wellbore, and the like.
BACKGROUNDCoiled tubing has proven increasingly useful in oil and gas field applications, including workovers, drilling, logging and well stimulation. Typically, coiled tubing units comprise a continuous length of several thousand feet (possibly up to 25,000 feet) of steel tubing, capable of withstanding pressures on the order of 15,000 psi, capable of being repeatedly coiled and uncoiled from a mobile spool, and capable of being injected and withdrawn from oil and gas wells without killing the well.
Coiled tubing lengths are generally understood in the field to comprise several hundred or several thousand feet of continuous, uniform outer diameter tubing, coilable on a truckable spool and injectable in a bore by means of a coiled tubing injector. The continuous lengths are typically, although not necessarily, manufactured of steel having a longitudinally welded seam. Resin and fiber polymer materials may also be used for continuous tubing. Typically, successive lengths of steel tubing are welded to create a desired unit length. In addition, coiled tubing is expected to be able to withstand significant pressure differentials, such as at least 1,000 psi and preferably closer to 15,000 psi, and to be sufficiently corrosive resistant and heat resistant to withstand exposure to common hydrocarbons downhole.
The term “truckable spool” means a spool or reel having an outside diameter of approximately six meters, and typically less, so that the spool can be transported by a boat or by a truck over land and highways to a site. Coiled tubing generally has sufficient flexibility to be reeled on a truckable spool and repeatedly coiled and uncoiled from such a spool or reel. Likewise, coiled tubing's ability to be injected in a bore means that the tubing, while flexible, is also sufficiently rigid that lengths of several hundred or thousand feet can be continuously thrust, or injected, in bores using coiled tubing injection equipment.
In addition to the applications mentioned above, coiled tubing has also been used in hydraulic fracturing applications. However, one drawback of current fracture methods is that they implement a single coil of tubing and there may be a risk of getting stuck within a wellbore due to the high frequency of screen outs that may occur during some treatment procedures, such as fracturing.
Oil and gas operations have known the use of concentric coiled-in-coiled pipe strings. Concentric pipe strings provide two non-well bore channels fir fluid communication downhole, typically, with one channel, such as the inner channel, used to pump fluid (liquid or gas or multiphase fluid) downhole while a second channel, such as the annular channel formed between the concentric strings, used to return fluid to the surface.
Existing systems, however, do not implement concentric or multi-centric coiled tubing in hydraulic fracturing applications as disclosed herein.
SUMMARYOne advantage of the disclosed system and methods is they provide an efficient system and method for treating a wellbore and recovery process that enables, if required, the removal of a screen out, treatment, proppant, and/or solids in each fracture created.
One embodiment of the present disclosure is a method of treating a wellbore comprising positioning an end of a coiled tubing string adjacent a portion of a wellbore, the coiled tubing string having a first flow area, a second flow area, and a valve configured to control flow out of the first and second flow areas into the portion of the wellbore. The method comprises treating a portion of the wellbore by pumping fluid down at least one of the first and second flow areas.
The method may include pumping fluid down both the first flow area and the second flow area to treat the portion of the wellbore. The method may include isolating the portion of the wellbore prior to treating the portion of the wellbore. Isolating the portion of the wellbore may comprises setting a plurality of isolating elements. The valve may be located proximal to the end of the coiled tubing string, The method may include actuating the valve and pumping fluid up the second flow area while pumping fluid down the first flow area. The valve may permit fluid and particulates in the portion of the wellbore to flow up the second flow area. Treating the wellbore may comprise fracturing a formation adjacent the portion of the wellbore. A screen out may have formed in a fracture during the fracturing of the formation. The method may include cleaning out the screen out from the portion of the wellbore. Actuating the valve and pumping fluid up the second flow path may clean out the screen out.
One embodiment of the present disclosure is a system to treat a portion of a wellbore. The system comprises a coiled tubing string having a first flow area and a second flow area and at least one valve configured to control flow of both the first and second flow areas out of the coiled tubing string. The system may include at least one isolation element. The valve of the system may be positioned proximate an end of the coiled tubing string. The system may include at least one port that permits communication from the first flow area and an exterior of the coiled tubing string and at least one port that permits communication from the second flow area and the exterior of the coiled tubing string, wherein the at least one valve is configured to control flow out both ports. The at least one isolation element may be actuated to isolate a portion of the wellbore. Fluid may be pumped down the first and second flow areas from a surface location to treat the isolated portion of the wellbore. The valve may be actuated so that fluid may be pumped down from the surface in the first flow area and pumped up to the surface in the second flow area. A formation of the portion of the wellbore may be fractured or stimulated by pumping fluid down both the first and second flow areas. Fluid pumped up to the surface in the second flow area may be used to remove a screen out of a fracture of the portion of the wellbore.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTIONThe portion of the wellbore 1 may be isolated from the rest of the wellbore by upper and/or tower isolating elements 120. Various isolation elements 120 that may be connected to a coiled tubing string 100 may be used with the coiled tubing string 100 disclosed herein. For example, the coiled tubing string 100 may be connected to the tool disclosed in U.S. patent application Ser. 14/318,952 entitled “Synchronic Dual Packer,” filed on Jun. 30, 2014, which is incorporated by reference herein in its entirety. The coiled tubing string 100 having two flow paths 101 and 102 with a valve 110 that may be actuated to control the flow of the flow paths 101 and 102 may be used with or without upper and lower isolation elements 120.
The coiled tubing string 100 may be used during various treatment procedures to treat a portion of a wellbore 1. For example, an acid may be delivered to a production zone to stimulate production. The coiled tubing string 100 having two flow paths 101 and 102 may also be used to fracture a formation 5 of a wellbore 1. As shown in
The portion of the wellbore being treated through the coiled tubing string 100 may require a clean out procedure. For example, during a fracturing procedure a screen out 10 may form in the fracture 6 and wellbore 1 as shown in
The various configurations of a coiled tubing string 100 having a first and second flow areas 101 and 102 are for illustrative purposes only. Various configurations may be used to form a coiled tubing string 100 having two flow paths 101 and 102 that may be controlled by one or more valves 110 as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure.
Although various embodiments have been shown and described, the present disclosure is not so limited and will be understood to include all such modifications and variations are would be apparent to one skilled in the art.
Claims
1. A method of treating a wellbore comprising:
- positioning an end of a coiled tubing string adjacent a portion of a wellbore, the coiled tubing string having a first flow area, a second flow area, and a valve configured to control flow out of the first and second flow areas into the portion of the wellbore; and
- treating the portion of the wellbore by pumping fluid down at least one of the first and second flow areas.
2. The method of claim 1, wherein treating the portion of the wellbore further comprising pumping fluid down both the first flow area and second flow area.
3. The method of claim 2, further comprising isolating the portion of the wellbore prior to treating the portion of the wellbore.
4. The method of claim 2, wherein isolating the portion of the wellbore further comprises setting a plurality of isolating elements.
5. The method of claim 3, wherein the valve is proximal the end of the coiled tubing string.
6. The method of claim 3, further comprising actuating the valve and pumping fluid up the second flow area while pumping fluid down the first flow area.
7. The method of claim 3, wherein the valve permits fluid and particulates in the portion of the wellbore to flow up the second flow area.
8. The method of claim 6, wherein treating further comprises fracturing a formation adjacent the portion of the wellbore.
9. The method of claim 8, wherein a screen out has formed in a fracture during the fracturing of the formation.
10. The method of claim 9, further comprising cleaning the screen out from the portion of the wellbore.
11. The method of claim 10, wherein actuating the valve and pumping fluid up the second flow path cleans out the screen out.
12. A system to treat a portion of a wellbore comprising:
- a coiled tubing string having a first flow area and a second flow area; and
- at least one valve configured to control flow of both the first and second flow areas out of the coiled tubing string.
13. The system of claim 12, further comprising at least one isolation element.
14. The system of claim 13, wherein the valve is positioned proximate an end of the coiled tubing string.
15. The system of claim 14, further comprising at least one port that permits communication from the first flow area and an exterior of the coiled tubing string and at least one port that permits communication from the second flow area and the exterior of the coiled tubing string, wherein the at least one valve is configured to control flow out both ports.
16. The system of claim 15, wherein the at least one isolation element may be actuated to isolate a portion of a wellbore.
17. The system of claim 16, wherein fluid may be pumped down the first and second flow areas from a surface location to treat the isolated portion of the wellbore.
18. The system of claim 17, wherein the valve may be actuated so that fluid may be pumped down from the surface in the first flow area and pumped up to the surface in the second flow area.
19. The system of claim 18, wherein a formation of the portion of the wellbore may be fractured or stimulated by pumping fluid down both the first and second flow areas.
20. The system of claim 19, wherein fluid pumped up to the surface in the second flow area may be used to remove a screen out of a fracture of the portion of the wellbore.
Type: Application
Filed: Sep 24, 2014
Publication Date: Mar 24, 2016
Inventors: Luis A. Castro (Spring, TX), Jaun Carlos Florex (The Woodlands, TX)
Application Number: 14/495,635