The embodiments described herein relate to an assembly and method for cementing an uncased or openhole portion of a wellbore through an assembly and producing a sidetrack of the wellbore with a single trip of the assembly into the wellbore. The assembly comprises a mill selectively connected to a whipstock with a snorkel tube positioned within a bore of the mill and a bore of the whipstock. Cement may be pumped down a drill string and through the snorkel tube to cement a portion of uncased wellbore. After cementing the wellbore, the mill may be removed from the assembly and used to provide a sidetrack of the wellbore without requiring a separate trip into the wellbore.
It may be desired to produce a sidetrack in an uncased portion of a wellbore. First the uncased portion of the wellbore needs to be cemented. A cementing assembly may be connected to a drill string and run down the wellbore until it is positioned into uncased portion of the wellbore. The entire wellbore may be uncased or the lower portion below the casing may be uncased. Cement is pumped down the drill string and out the assembly to cement the uncased portion of the wellbore. After cementing the uncased bore of a wellbore, the drill string may be removed from the wellbore and a mill may be run down the wellbore. When the mill is positioned adjacent to the newly cemented portion of the wellbore, the mill will be actuated and moved downward. The mill will continue to travel down the wellbore until it engages a whipstock, which changes the direction of the mill causing it produce a sidetrack of the wellbore.
The repeated trips down the wellbore to positioned the cementing assembly, remove the drill string, and positioned the mill above the whipstock are time consuming and costly. It would be beneficial to reduce the amount of time required to produce a sidetrack of the wellbore.
The present disclosure is directed to a method and system for cementing a portion of an uncased wellbore and milling a sidetrack to the wellbore with a single trip assembly.
One embodiment is an assembly for use to cement an uncased wellbore comprising a whipstock having a bore and a deflection surface to deflect a mill to move substantially lateral from the deflection surface, a mill having a bore and being selectively connected to an upper end of the whipstock, and a snorkel tube. The snorkel tube is positioned within the bore of the mill and positioned within the bore of the whipstock. Cement may be pumped through the snorkel tube to a location below the whipstock.
The snorkel tube may be comprised of a drillable material. The drillable material may be comprised of aluminum or a composite material. The assembly may include a seal sub having a bore and being connected to the bottom end of the whipstock. The snorkel tube may extend into the bore of the seal sub. The assembly may include a pup joint having a bore connected beneath the seal sub. The snorkel tube may extend into the bore of the pup joint. The assembly may include an open hole anchor having a bore in communication with the snorkel tube and the anchor may be connected beneath the pup joint.
The assembly may include a landing collar connected beneath the open hole anchor. The landing collar may include a bore in communication with the bore of the open hole anchor. The assembly may include a float collar connected beneath the landing collar. The float collar may have a bore in communication with the bore of the landing collar. The assembly may include a tail pipe connected beneath the float collar. The tail pipe may have a bore in communication with the bore of the float collar. Cement may be pumped through the snorkel tube, the open hole anchor, the landing collar, the float collar, and out the tail pipe.
A shearable device may selectively connect the mill to the upper end of the whipstock. A plug may be pumped down a drill string to land within the bore of the mill. The end of the plug may comprise a cutting structure. A locking device may selectively secure the snorkel tube within the bore of the mill. A release device may be pumped down a drill string to selectively unlock the locking device that selectively secures the snorkel tube within the bore of the mill. The unlocked locking device may prevent the downward movement of the snorkel tube within the bore of the mill, but may permit the upward movement of the snorkel tube within the bore of the mill. The snorkel tube may include a fin or a plurality of fins on an exterior surface. The upper end of the snorkel tube may include a profile that permits the removal of the snorkel tube from the bore of the mill via a slickline, wireline, or a braided line.
One embodiment is a method of cementing through a whipstock and creating a sidetrack to a wellbore in a single trip. The method comprises running an assembly connected to a drill string into a wellbore. The assembly comprises a mill selectively connected to an upper end of a whipstock, a snorkel tube positioned within a bore of the mill and positioned within a bore of the whipstock, an open hole anchor having a bore in communication with the snorkel tube, and a tail pipe connected beneath the open hole anchor, the tail pipe having a bore in communication with the snorkel tube. The method includes setting the open hole anchor within an open hole portion of the wellbore and pumping cement down the drill string, through the snorkel tube, and out the tail pipe. The method includes releasing the mill from the upper end of the whipstock and cutting a sidetrack in the wellbore with the mill.
The method may include shearing a shearable device that selectively connected the mill to the upper end of the whipstock. The method may include cutting off a portion of the snorkel tube with the mill prior to cutting the sidetrack in the wellbore. The method may include pumping a plug down the drill string after releasing the mill from the upper end of the whipstock. The end of the plug may comprise a cutting surface. The method may include landing the plug in the bore of the mill and cutting off a portion of the snorkel tube with the mill prior to cutting the sidetrack in the wellbore.
The method may include pumping a release device down the drill string to selectively release the snorkel from the bore of the mill after releasing the mill from the upper end of the whipstock. The release device may permit the snorkel tube to move upwards within the bore of the mill and may prevent the snorkel tube to move downwards within the bore of the mill. The method may include pumping the snorkel tube up the drill string prior to cutting the sidetrack in the wellbore. The method may include retrieving the snorkel tube from the bore of the mill after releasing the mill from the whipstock and prior to cutting the sidetrack in the wellbore. The method may include engaging a profile on an upper end of the snorkel tube with wireline, slickline, or a braided line.
One embodiment is a method of cementing an openhole wellbore through a whipstock and creating a sidetrack in a single trip. The method includes running an assembly connected to a drill string into a wellbore. The assembly comprises a mill selectively connected to an upper end of a whipstock by a shearable device, a snorkel tube positioned within a bore of the mill and positioned within a bore of the whipstock, and an open hole anchor, wherein the drill string is connected to the mill. The method includes setting the open hole anchor within an open portion of the wellbore and pumping cement down the drill string and through the snorkel tube and the open hole anchor to cement a portion of the open hole wellbore. The method includes shearing the shearable device to release the mill from the upper end of the whipstock and moving the mill uphole within the wellbore. The method includes milling a portion of the snorkel tube that extends above the whipstock, engaging a diverting surface of the whipstock with the mill, and cutting a sidetrack in the wellbore with the mill.
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 scope of the invention as defined by the appended claims.
The assembly 100 is comprised of a mill 10 that is selectively connected to a portion of a whipstock 20. A shearable device 12, such as a shear bolt, may be used to selectively connect the mill 10 to the whipstock 20. The bottom portion of the whipstock 20 may be connected to seal sub 40 that is connected to an open hole anchor 60 via a pup joint 50. The assembly 100 may include a landing collar 70, a float collar 80, and a tail pipe 90 positioned below the open hole anchor 60.
After the anchor 60 has been actuated to retain the assembly 100 at the desired location, cement 5 may be pumped down the drill string 4 and out the tail pipe 90 to cement the open hole portion 3 of the wellbore 1. The cement 5 is pumped down the drill string 4 and through a snorkel tube 30 positioned within a bore 11 of the mill 10. The snorkel tube 30 is also positioned within a bore 21 of the whipstock 20. The cement 5 travels down through the seal sub 40, pup joint 50, anchor 60, landing collar 70, float collar 80, and out the tail pipe 90 to cement the uncased portion 3 of the wellbore 1 as shown in
A downward force may be applied to the drill string 4 to shear the shearable device 12 releasing the mill 10 from the whipstock 20 as shown in
In some embodiments, an open hole anchor 60 is positioned beneath the pup joint 50. The open hole anchor 60 may be actuated by dropping a ball down the drill string 4 until the ball seats within the landing collar 70. After the ball has seated, the pressure within the drill string 4 may slowly be increased until the anchor 60 is fully actuated. The pressure within the drill string 4 may continue to be increased to shear the ball through the landing collar 70. The drill string 4 may then be pulled and also set down to ensure that the anchor 60 is fully set within the uncased portion 3 of the wellbore 1. After the anchor 60 is fully set, cement may be pumped down the drill string 4 and out the tail pipe 90 to cement the uncased portion 3 of the wellbore 1. The bore 91 of the tail pipe 90 is in fluid communication with the drill string 4 via the snorkel tube 30 as well as the bore 81 of the float collar, the bore 71 of the landing collar 70, and the bore 61 of the anchor 60.
After releasing the mill 10 from the whipstock 20, the drill string 4 may be pulled to raise the mill 10 above the end of the snorkel tube 30 as shown in
The drill string 4 may then be lowered while the mill 10 is actuated to mill away the snorkel tube 30 until the mill 10 engages the deflection surface 22 of the whipstock 20, which causes the mill 10 to travel towards the edge of the wellbore 1 instead of traveling in a strictly downwards direction. The deflection surface 22 of the whipstock 20 causes the mill 10 to create a sidetrack 6 in the wellbore 1 as shown in
After releasing the mill 10 from the whipstock 20, the drill string 4 may be pulled to raise the mill 10 pulling the snorkel tube 30 up with the mill 10 as shown in
After the device 15 has been pumped down the drill string 4 and released the snorkel tube 30, the snorkel tube 30 may be pumped up the drill string 4 by reverse circulation as shown in
After releasing the mill 10 from the whipstock 20, the drill string 4 may be pulled to raise the mill 10 pulling the snorkel tube 30 up with the mill 10 as shown in
The top end of the snorkel tube 30 of assembly 100D includes a profile 32 as shown in
After removal of the snorkel tube 30 up the drill string 4 via the wireline 7, the mill 10 may then be actuated to start rotating. The drill string 4 may then be lowered while pumping fluid down the drill string 4 and out the bore 11 of the mill 10. The mill 10 will be lowered until the mill 10 engages the deflection surface 22 of the whipstock 20, which causes the mill 10 to travel towards the edge of the wellbore 1 instead of traveling in a strictly downwards direction. The deflection surface 22 of the whipstock 20 causes the mill 10 to create a sidetrack 6 in the wellbore 1 as shown in
Although this invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art, including embodiments that do not provide all of the features and advantages set forth herein, are also within the scope of this invention. Accordingly, the scope of the present invention is defined only by reference to the appended claims and equivalents thereof.