BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows one embodiment of an annular fracturing combo tool on the end of coiled tubing 10 above a first zone of interest 100 that has previously been perforated and fractured.
FIG. 2 shows the annular fracturing combo tool of FIG. 1 beginning to perforate the well at a new zone of interest.
FIG. 3 shows the annular fracturing combo tool moved below the perforations providing an annular flow path to fracturing the new zone of interest.
FIG. 4 shows the annular fracturing combo tool moved below the perforations and disconnected from the coiled tubing providing an annular flow path to fracturing the new zone of interest.
FIG. 5 is a cross-section view of collar locator 60 positioned within a collar 70 of the well casing.
FIG. 6 is a cross-section view of one embodiment of a collet connector 46 connecting coiled tubing 10 to the top end 41 of an annular fracturing combo tool.
FIG. 7 is a cross-section view of the collet connector 46 disconnected from the top end 41 of the annular fracturing combo tool.
While the invention 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 invention 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
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
Illustrative embodiments of the invention are described below as they might be employed in the method of perforating and annular fracturing a wellbore with an annular fracturing combo tool releasably connected to the bottom of coiled tubing that allows for multiple zones to be abrasively perforated and fractured in a single trip into the well. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
Further aspects and advantages of the various embodiments of the invention will become apparent from consideration of the following description and drawings.
FIG. 1 shows one embodiment of the annular fracturing combo tool of the present disclosure that includes a collar locator 60, a retrievable bridge plug 50, a yo-yo disconnect tool 40, and a sand jetting sub 30. The collar locator 60 is connected beneath the retrievable bridge plug 50 and is used to determine when the annular fracturing combo tool is within a particular zone of interest in the well based on collars 70 located in the well casing 20. Although the embodiment of FIG. 1 includes a collar locator, this device may be one of a various number of downhole devices used to determine the location of a downhole assembly within a wellbore. The yo-yo disconnect tool 40 (shown in FIG. 4) releasably connects to the annular fracturing combo tool to the bottom end of the coiled tubing 10 that has been adapted to include connector 45, which connects with the yo-yo disconnect tool 40.
Once the annular fracturing combo tool has been located within the new zone of interest and the sand jetting sub 30 is positioned at the proper location, an abrasive laden fluid may be pumped at a high pressure down the coiled tubing 10 and through the jetting ports 35 on the exterior of the sand jetting sub 30. For example, 20/40 Ottowa sand may be pumped through the sand jetting sub 30 to perforate 200 the casing 20 at the desired location as shown in FIG. 2. Using 20/40 Ottowa sand pumped through the sand jetting sub 30 may perforate the casing at the zone of interest in as little as twenty minutes. The annular fracturing combo tool may also be used to perforate and fracture tubing as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure. The configuration of the jetting ports 35 of the sand jetting sub 30 may be varied to change the number and locations of perforations created by the sand jetting sub 30. The configuration of the individual jetting ports 35 may also be changed to modify the cutting power of the sand jetting sub 30.
After the casing or tubular has been perforated, the coiled tubing is run down the casing 20 until the annular fracturing combo tool is located below the perforations 200 in the zone of interest as shown in FIG. 3. The annular fracturing combo tool is moved away from the perforations 200 to provide a sufficient annular flow path to allow stimulation of the perforations 200. After the annular fracturing combo tool is properly positioned, the retrievable bridge plug 50 may then be set to hydraulically isolate the zone of interest. A cup type retrievable bridge plug may be preferred in this application as a cup type retrievable bridge plug may be set by using differential pressure from either above or below the bridge plug. Also a cup type retrievable bridge plug may be ideal for this application because the bridge plug may be released by merely pulling up with the coiled tubing. Although the embodiment of FIG. 1 includes a retrievable bridge plug, one of ordinary skill in the art having this disclosure would appreciate a number of different packing devices that may be run and set with coiled tubing which may be used with the annular fracturing combo tool to isolate a zone within the wellbore.
Once the retrievable bridge plug 50 is set, fracturing fluid may then be pumped down the annulus 15 between the coiled tubing 10 and the casing 20. Fracturing fluid is pumped down at a high pressure in an attempt to propagate the perforations 200 in the zone of interest into fractures 300 in the formation as shown in FIG. 3. The set bridge plug 50 isolates the zone and aids in allowing the high pressure fracturing fluid to propagate the fractures in the formation. Fluid may be pumped down the coiled tubing 10 and circulated out of the jetting ports 35 while fracturing fluid is being pumped down the annulus 15. The fluid circulated out of the jetting ports 35 may help to prevent proppant located in the fracturing fluid from accumulating on the annular fracturing combo tool.
FIG. 4 shows that the coiled tubing 10 may be released from the annular fracturing combo tool after the retrievable bridge plug 50 has been set hydraulically isolating the zone of interest. In one embodiment, a yo-yo disconnect tool 40 is used to releasably connect the annular fracturing combo tool to the coiled tubing 10, the end of the coiled tubing 10 being adapted with connector 45 to releasably connect to the yo-yo disconnect tool 40. A yo-yo disconnect tool 40 may be ideal for this application because it releases the annular fracturing combo tool simply by picking up on the coiled tubing 10, but a different releasable connector may be used with the annular fracturing combo tool as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure. Once the coiled tubing 10 has been disconnected from the annular fracturing combo tool, fracturing fluid may then be pumped down the annulus 15 between coiled tubing 10 and the casing 20. As discussed above, the set bridge plug 50 isolates the zone and aids in allowing the high pressure fracturing fluid to propagate the fractures in the formation as discussed above.
After the zone of interest has been stimulated, the connector 45 of the coiled tubing 10 may be re-connected to the yo-yo disconnect tool 40 and the retrievable bridge plug 50 may be deactivated allowing the pressure in the zone of interest to equalize with the well pressure below. The annular fracturing combo tool may then be positioned in the next zone of interest using the collar locator 60. Once properly position in the new location, the sand jetting sub 30 may begin perforating a specified location of the casing 20 or tubing. After the casing has been perforated, the annular fracturing combo tool may be moved below the perforations and the bridge plug 50 may be set to hydraulically isolate the zone to be fractured. The configuration of this annular fracturing combo tool allows multiple zones of a well to be perforated and fractured in a single trip. FIG. 4 is a cross section of the collar locator 60 positioned within a collar 70 of the well casing 20. As discussed above, the collar locator 60 allows the coiled tubing operator to position the annular fracturing combo tool within a desired zone of the wellbore.
FIG. 6 shows one embodiment of a collet connector 46 that may be used to releasably connect coiled tubing 10 to the top end 41 of an annular fracturing combo tool. The collet connector 46 includes collet fingers 47, which include an end portion 48 adapted to retain a collar 42 of the top end 41 of the annular fracturing combo tool. When the collect connector 46 is connected to the top end 41 of the annular fracturing combo tool, the collar 42 is positioned between the end portions 48 and the collet 46. The lower inner portion of the collet 46 and the upper inner portion of the collet end portion 48 are adapted to mate against the collar 42 securing the coiled tubing 10 to the annular fracturing combo tool.
The collar 42 of the annular fracturing combo tool is positioned within the collet connector 46 prior to insertion into the well. The coiled tubing 10 may then be used to run the annular fracturing combo tool to a desired location within the well. As discussed above, a collar locator may be used to determine when the annular fracturing combo tool is within a particular zone of interest in the well. The annular fracturing combo tool may then be used to perforate the casing and/or tubing at a desired location. After the casing and/or tubular has been perforated, the coiled tubing 10 is run down until the annular fracturing combo tool is located below the perforations in the zone of interest. The collet connector tool may then be moved away from the perforations to provide a sufficient annular flow path to allow stimulation of the perforations as discussed above.
After the annular fracturing combo tool is properly positioned, the retrievable bridge plug of the annular fracturing combo tool may then be set to hydraulically isolate the zone of interest. Additionally, the retrievable bridge plug is set to allow the coiled tubing operator to disconnect the collet connector 46 from the top end 41 of the annular fracturing combo tool. Once the bridge plug has been set, the coiled tubing operator may begin to pull up on the coiled tubing 10. The set bridge plug holds the annular fracturing combo tool in place within the well bore against the upward force from the coiled tubing. The coiled tubing operator will continue to increase the upward force on the coiled tubing until the collet connector 46 disconnects from the annular fracturing combo tool. When the upward force on the coiled tubing 10 reaches a designated load, the collet fingers 47 release from the collar 42 of the top end 41 of the annular fracturing combo tool as shown in FIG. 7. The collet connector 46 and corresponding collar 42 are designed such that the designated upward release force is less than the maximum force that the set bridge plug can withstand as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure. Depending upon bridge plug design, application of annular pressure may be required to create sufficient resistance for the collet tool to pull against.
The bottom shoulder 39 of the collar 42 and the upper face 49 of the end portion 38 of the collet fingers 47 may be angled to facilitate outward movement of the collar fingers 47 when a designated upward load has been exerted on the coiled tubing 10. The outward movement of the collar fingers 47 releases the collar 42 disconnecting the coiled tubing 10 from the annular fracturing combo tool. The collet connector 46 may reconnect the coiled tubing 10 to the combo annular fracturing tool by moving the collect connector 46 downwards until end portions 48 of the collet fingers 47 snap over the bottom shoulder 39 of collar 42. The collet connector 46 and corresponding top end 41 of the annular fracturing combo tool allow the annular fracturing combo tool to be repeatedly connected and disconnected to the coiled tubing in the well bore.
Although various embodiments have been shown and described, the invention is not so limited and will be understood to include all such modifications and variations as would be apparent to one skilled in the art.
Patent Application
20080066917
