Methods and systems for fracing

Abstract

A frac plug with a flapper positioned within a shearable housing. More specifically, embodiments are directed towards an upper portion of the shearable housing that is configured to be separated from an insert responsive to flowing back through the frac plug.

Claims

1. A downhole tool comprising: a shearing housing positioned within a mandrel with an upper portion and a lower portion; stress points positioned between the upper portion and the lower portion along a longitudinal axis of the mandrel, the stress points coupling the upper portion and the lower portion and having a smaller diameter than the mandrel; an object being configured to isolate a first area above the shearing housing from a second area below the shearing housing, the object being positioned across and within the shearing housing before the object and the shearing housing are positioned within a hole, the object being positioned between the upper portion of the shearing housing and the lower portion of the shearing housing along the longitudinal axis of the mandrel, the upper portion being configured to be sheared from the lower portion based on applied pressure to the stress points via the object being greater than a stress threshold, the object being coupled to the shearing housing via a pin extending into the object; wherein the first area and the second area are isolated from each other before and after the lower portion and the upper portion are sheared from each other.

2. The downhole tool of claim 1, wherein a lower surface of the object is configured to be seated on the lower portion of the shearing housing.

3. A downhole tool, comprising: a shearing housing with an upper portion and a lower portion, the shearing housing being positioned within a mandrel, the upper portion of the shearing housing being configured to be sheared from the lower portion of the shearing housing based on applied pressure to stress points via an object being greater than a stress threshold, the object being positioned between the upper portion and the lower portion along a longitudinal axis of the mandrel, wherein the stress points are positioned between the upper portion and the lower portion along the longitudinal axis of the mandrel, the stress points coupling the upper portion and the lower portion and having a smaller diameter than the mandrel; a first area above the shearing housing; a second area below the shearing housing, the object being positioned within the shearing housing before being positioned within a hole, the object extending across the housing to isolate a first area from the second area; wherein the first area and the second area are isolated from each other before and after the lower portion and the upper portion are sheared from each other; a downhole tool having a ledge and a tapered sidewall, the tapered sidewall being configured to receive the lower portion of the shearing housing after the lower portion of the shearing housing being sheared from the upper portion of the shearing housing, and the upper portion of the shearing housing is configured to be positioned on the ledge before and after the lower portion of the shearing housing and the upper portion of the shearing housing are sheared from each other.

4. The downhole tool of claim 3, wherein the upper portion of the shearing housing is configured to flow towards a proximal end of the downhole tool responsive to flowing fluid towards the proximal end of the downhole tool after the upper portion of the shearing housing is sheared from the lower portion of the shearing housing to allow communication between the first area and the second area.

5. The downhole tool of claim 4, further comprising: locking outcrops positioned on an outer diameter of the shearing housing, the locking outcrops having a first diameter which is greater than a second diameter associated with a distal end of the downhole tool, wherein the locking outcrops are configured to restrict the movement of the lower portion of the shearing housing towards the proximal end of the downhole tool when the upper portion of the shearing housing is flowing towards the proximal end of the downhole tool.

6. The downhole tool of claim 3, wherein the downhole tool is an insert, and the insert is configured to be positioned between an outer diameter of the shearing housing and an inner diameter of the mandrel.

7. The downhole tool of claim 3, further comprising: pin slots within the downhole tool, the pin slots are configured to receive a pin associated with the object, the pin slots being configured to allow the object to be free floating.

8. The downhole tool of claim 3, wherein the tapered sidewall of the downhole tool is configured to limit movement of the lower portion of the shearing housing towards a distal end of the downhole tool.

9. The downhole tool of claim 3, wherein at least one of the downhole tool and the shearing housing is formed of a dissolvable material.

10. A downhole tool comprising: a shearing housing with an upper portion and a lower portion, the upper portion of the shearing housing being configured to be sheared from the lower portion of the shearing housing within a mandrel based on applied hydraulic pressure to stress points via an object being greater than a stress threshold, the object being positioned between the upper portion and the lower portion of the shearing housing before being positioned within a hole; a first area above the shearing housing; a second area below the shearing housing, the object extending across the shearing housing to isolate a first area from the second area; wherein the first area and the second area are isolated from each other before and after the lower portion and the upper portion are sheared from each other; the stress points positioned between the upper portion and the lower portion along a longitudinal axis of the mandrel, wherein the upper portion of the shearing housing is configured to be sheared from the lower portion of the shearing housing via the stress points; gaps that are radially positioned between the stress points to control a width of the stress points, the object being coupled to the shearing housing via a pin extending into the object and the gaps.

11. A method comprising: shearing an upper portion of a shearing housing and a lower portion of the shearing housing based on applied pressure to the shearing housing via an object being greater than a stress threshold, the object being positioned between the upper portion and the lower portion, the object being run in hole extending across the shearing housing to isolate a first area above the shearing housing from a second area below the shearing housing; isolating the first area above the shearing housing and the second area below the shearing housing before and after the lower portion and the upper portion are sheared from each other; moving the upper portion towards a proximal end of a downhole tool responsive to flowing fluid towards the proximal end of the downhole tool after the upper portion has been sheared from the lower portion; allowing communication between the first area and the second area.

12. The method of claim 11, further comprising: restricting the movement of the lower portion of the shearing housing towards the proximal end of the downhole tool when the upper portion of the shearing housing is flowing towards the proximal end of the downhole tool.

13. The method of claim 11, wherein the shearing housing is configured to be positioned on an insert, and positioning the insert between an outer diameter of the shearing housing and an inner diameter of a mandrel, wherein an upper surface of the object and a lower surface of the object are positioned within the shearing housing.

14. The method of claim 13, wherein at least one of the downhole tool and the shearing housing is formed of a dissolvable material.

15. The method of claim 11, further comprising: positioning a pin associated with the object within pin slots, the pin slots being configured to allow the object to be free floating.

16. A downhole tool comprising: a shearing housing with an upper portion and a lower portion; an object being positioned between the upper portion and the lower portion, the object being configured to be positioned within a hole extending across and within the shearing housing to isolate a first area above the shearing housing from a second area below the shearing housing, the upper portion being configured to be sheared from the lower portion based on applied pressure to the shearing housing via the object in a first direction being greater than a stress threshold; wherein the first area and the second area are isolated from each other before and after the lower portion and the upper portion are sheared from each other until fluid is flowed in a second direction that separates the upper portion and the object from the lower portion, wherein the first direction and second direction are opposite directions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

(2) FIG. 1 depicts a downhole tool, according to an embodiment.

(3) FIG. 2 depicts a downhole tool, according to an embodiment.

(4) FIG. 3 depicts a downhole tool, according to an embodiment.

(5) FIGS. 4 and 5 depict a perspective view of an insert and housing, according to an embodiment.

(6) FIG. 6 depicts an operation sequence for shearing a housing with a flapper, according to an embodiment.

(7) FIG. 7 depicts a downhole tool, according to an embodiment.

(8) Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present disclosure. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present disclosure.

DETAILED DESCRIPTION

(9) In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present invention. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present invention.

(10) FIG. 1 depicts a downhole tool 100, according to an embodiment. Downhole tool 100 may be a frac plug that is configured to isolate areas of a geological formation. Downhole tool 100 may include a mandrel 110, insert 120, and housing 130.

(11) Mandrel 110 may be a shaft, cylindrical, rod, etc. that is configured to form a body of downhole tool 100. Mandrel 110 may include a profile 112 that reduces an inner diameter of mandrel 110 that limits the movement of insert 120 in a first direction. Profile 112 may be a ledge that is perpendicular to a central axis of downhole tool 100 or may be a tapered sidewall that gradually and incrementally decreases the inner diameter of mandrel 110.

(12) Insert 120 may be a tool formed of composite material, or any desired material. Insert 120 may be configured to be mounted on an inner diameter of mandrel 110 of downhole tool 100. Insert 120 may include ledge 122, sloped sidewall 124, distal end 126, and pin slots 128. Insert 120 may be threaded, glued or pinned or fixed to Mandrel 110 using any other method.

(13) Ledge 122 may decrease an inner diameter across insert 120, which may be configured to act as a stopper, no-go, etc. to restrict the movement of an upper portion of housing 130 in a first direction, wherein the first direction may be downhole. More specifically, ledge 122 may be configured to receive a projection 142 of upper portion 140 of the housing 130. Responsive to positioning projection 142 of upper portion 140 on ledge 122, movement of housing 130 in the first direction may be restricted when upper portion 140 and lower portion 150 are coupled together. However, when upper portion 140 and lower portion 150 are decoupled, ledge 122 may not restrict the movement of lower portion 150 in the first direction.

(14) Sloped sidewall 124 may be configured to gradually decrease the inner diameter of the insert 120. Sloped sidewall 124 may be configured to receive lower portion 150 of housing 130 to restrict the movement of lower portion 150 in the first direction responsive to decoupling upper portion 140 and lower portion 150. In embodiments, an angle of the sloped sidewall may correspond to the tapered sidewall of mandrel 110. Furthermore, a seal may be formed between an outer diameter of lower portion 150 and an inner diameter of insert 120 when lower portion 150 and upper portion 140 are de-coupled.

(15) The distal end 126 of the insert 120 may project away from an inner diameter of the mandrel 110 to create a lower shelf. Distal end 126 may be configured to interface with elements locking outcrops 154 of lower portion 150 to limit the movement of lower portion 150 in a second direction. In certain embodiments, tool 100 may not include an insert 120 and housing 130 may be directly mounted on mandrel 110, wherein mandrel 110 may have a similar inner profile as that described above.

(16) Pin slots 128 may be holes, slots, indentations, etc. positioned through insert that are configured to selectively receive flapper pin 137. Specifically, pin slots 128 may have a first end that is positioned on the proximal end of insert 120 and extend towards a distal end of insert 120. Pin slots 128 may extend in a linear path with a larger length than that of flapper pin 137, which may allow flapper pin 137 to be free floating within pin slots 128. The proximal end of pin slots 128 may be configured to be contained between the upper portion 140 and lower portion 150 of housing 130 when upper portion 140 and lower portion 150 are coupled together. After flapper pin 137 is disengaged from pin slots 128 it may be unlikely that flapper pin 137 can reengage with pin slots 128 downwell.

(17) Housing 130 may be formed of brass, composite, aluminum, cast iron or any other material that can dissolve over time due well fluid and temperature. Housing 130 may be configured to be positioned within insert 120 when run in hole, wherein elements of housing 130 may all be coupled together when run in hole. The housing 130 may include a flapper 135, upper portion 140, and lower portion 150. In other embodiments, the flapper 135 and flapper pin 137 may be replaced by disc or any geometrical shape.

(18) Flapper 135 may be a rotatable disc formed of brass, composite, aluminum, cast iron or any other material that can dissolve over time due well fluid and temperature. Flapper 135 may be configured to rotate from a position blocking an inner diameter of the tool 100 to a position allowing fluid to flow around flapper 135. When flapper 135 extends across an annulus within tool, flapper 135 may be configured to be positioned on a flapper seat 158 within the lower portion of housing. When flapper 135 is positioned on flapper seat 158, whether upper portion 140 and lower portion 150 are coupled or decoupled from each other, a first area on a first side of flapper 135 may be isolated from a second area on a second side of flapper 135. However, if flapper 135 is rotated to not extend across the annulus within tool 100 and/or upper portion 140 is not positioned within insert 120, then the first area and second area may not be isolated from each other. Flapper 135 may be a free floating component that is mounted inside the housing 130 via a flapper pin 137 and insert 120. Flapper 135 may be configured to apply forces when pressure or forces are applied to flapper 135 from above against stress points 146 within housing 130 to separate upper portion 140 and lower portion 150 of housing.

(19) Flapper pin 137 may be a free floating, which enables flapper 135 to move along a linear axis confined by pin slots 128. Flapper pin 137 configured to extend across an entirety of the diameter of housing and have ends that are configured to be inserted into pin slots 128. When flapper pin 137 is inserted into the pin slots 128, flapper 135 may be couple housing 130 and insert 120. In embodiments, flapper pin 137 may be an integral portion of flapper 135 or may be removably coupled to flapper 135, such that flapper pin 137 may slide out of flapper 135.

(20) Upper portion 140 of housing 130 may be configured to be selectively coupled to lower portion 150 of housing 130 based on a pressure applied across housing 130 and a direction of fluid flowing within tool 100. Upper portion 140 may include projection 142 and stress points 146. In other embodiments, upper portion 140 and lower portion 150 may be two elements connected together via weak point 146 which can be a shear screw.

(21) Projection 142 may be positioned on a proximal end of upper portion 140 and project away from a central axis of housing 130 to increase an outer diameter of upper portion 140. Projection 142 may be configured to slide onto and sit on ledge 122. Responsive to positioning projection 142 on ledge 122, movement of upper portion 140 in the first direction may be limited.

(22) Stress points 146 may be positioned between upper portion 140 and lower portion 150 of housing 130. Stress points 146 may be weak points where upper portion 140 becomes disconnected from lower portion 150. In embodiments, stress points 146 may be configured to receive a force from flapper 135 against flapper seat 158 responsive to moving the free floating flapper 135 to be positioned on flapper seat 158. More specifically, when fluid is flowing through the inner diameter of tool 100, flapper 135 may receive forces created by the flowing fluid/pressure. This may allow flapper 135 to seat on the lower portion 150 of the housing 130, and cause flapper 135 to apply a pressure against the stress points 146. When flapper 135 applies a pressure greater than a stress threshold of stress points 146, stress points 146 may break causing upper portion 140 and lower portion 150 to become detached and separated. Then, lower portion 150 of housing may move in the first direction towards the distal end of the housing 130 with the flapper 135 and flapper pin 137.

(23) Lower portion 150 of housing 130 may be configured to be selectively coupled to upper portion 140 of housing 130. Lower portion 150 may include seal 152, locking outcrops 154, and tapered sidewall 156. Seal 152 may be configured to be positioned between an outer diameter of the lower portion 150 and an inner diameter of inset 120. Seal 152 may not allow communication through a gap between insert 120 and housing 130 when lower portion 150 is still connected to the upper portion 150 of the housing 130, and when flapper 135 is positioned on flapper seat 158. Locking outcrops 154 may be positioned on the distal end of lower portion 150 below the distal end 126 of insert 120.

(24) Locking outcrops 154 may increase an outer diameter of the lower portion 150 such that a diameter of locking outcrops 154 is larger than that of distal end 126. Due to locking outcrops 154 being larger in size than that of the outer diameter of the distal end 126 and internal diameter of the lower end of insert 120, locking outcrops 154 may restrict the movement of lower portion 150 in a second direction relative to insert 120, wherein the second direction is an opposite position from the first direction. This may assist in the disengaging the upper portion 140, flapper 135 and flapper pin 137 from the lower portion 140 when there is a flow back through tool 100. Further, by restricting lower portion 150 from moving in the second direction using locking outcrops 154 and the first direction using ledge 122, the lower portion 150 can be milled with the frac plug as an integral piece. Hence facilitating milling operation if needed.

(25) Tapered sidewall 156 may be a slanted sidewall that is configured to be positioned on slanted sidewall 124 of insert 120 after lower portion 150 is sheared from upper portion 140.

(26) Flapper seat 158 may be positioned between stress points 146 and locking outcrops 154. Flapper seat 158 may be configured to reduce the inner diameter across lower portion 150, such that flapper 135 may be positioned on flapper seat 158. Responsive to flapper 135 receiving pressure above the flapper 135 in the first direction, flapper 135 may translate these forces to lower portion 130 through flapper seat 158, which may shear stress points 146.

(27) FIG. 2 depicts a downhole tool 100, according to an embodiment. Elements depicted in FIG. 2 may be described above, and for the sake of brevity a further description of these elements is omitted. Once tool 100 is set at a desired depth with flapper 135 being in the closed position, a pressure above flapper 135 may increase past the stress threshold. Responsive to pressure in a first direction, flapper 135 may apply a pressure against stress points 146 that is greater than a stress threshold. This may cause stress points 146 to break. When stress points 146 break, upper portion 140 and lower portion 150 may become decoupled.

(28) When the pressure is applied stress points 146 via flapper 135, to decouple upper portion 140 and lower portion 150, lower portion 150 may slide in the first direction. However, due to the restriction created by ledge 122, upper portion 140 may not be able to move in the second direction.

(29) Furthermore, lower portion 150 may slide downhole creating a gap between upper portion 140 and lower portion 150. Yet, because of sloped sidewall 124 the movement of lower portion 150 in the first direction may be limited. As such, after stress points 146 break, both upper portion 140 and lower portion may be separated from each other but still retained within insert 120. Further, flapper 135 will continue to isolate pressure above from pressure below as it will continue to be seated on flapper seat 158.

(30) FIG. 3 depicts a downhole tool 100, according to an embodiment. Elements depicted in FIG. 3 may be described above, and for the sake of brevity a further description of these elements is omitted. After upper portion 140 and lower portion 150 are decoupled from each other and there is fluid flowing through tool 100 in the second direction, upper portion 140, flapper 135 and flapper pin 137 may be removed from insert 120.

(31) When flapper 135, flapper pin 137 and upper portion 140 move in the second direction, lower portion 150 may remain within insert 120 due to locking outcrops 154.

(32) In embodiments, based on the geometry of flapper 135, flapper pin 137 and upper portion 140 it will be extremely unlikely or not statistically possible for flapper 135 and flapper pin 137 to be reinserted into pin slots 128 and seal on flapper seat 158. Furthermore, because flapper 135 may be formed of a dissolvable material over time it may become impossible for flapper 135 to seal across housing 130 due to its decrease in size.

(33) FIGS. 4 and 5 depict a perspective view of insert 120 and housing 130, according to an embodiment. Elements depicted in FIGS. 4 and 5 may be described above, and for the sake of brevity a further description of these elements is omitted. As depicted in FIGS. 4 and 5 pin slots 128 within insert 120. Pin slots 128 may extend from an upper end of insert 120 towards the lower end of insert. However, when upper portion 140 is coupled with lower portion 150, upper portion 140 may restrict the upward movement of pin 137 of flapper 135, such that flapper 135 may remain within insert until upper portion 140 is decoupled from lower portion 150.

(34) Furthermore, as depicted in FIGS. 4 and 5, housing 130 may include a series of windows/gaps that separates stress points 146 from each other's. These gaps may be used to control the width of the stress points 146, which may control the threshold of its shearing/failing, further these windows may allow flapper pin 137 to be inserted through housing 130 and into pin slots 128 which is part of insert 120. In other embodiments, slot 128 may be directly engraved into mandrel 100.

(35) FIG. 6 depicts an operation sequence for shearing a housing with a flapper, according to an embodiment. The operational sequence presented below is intended to be illustrative. In some embodiments, operational sequence may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of operational sequence are illustrated in FIG. 6 and described below is not intended to be limiting.

(36) At operation 610, a frac plug may be run in hole and set at desired depth. The frac plug may be run in hole with a flapper being in a closed position across a housing.

(37) At operation 620, the pressure above the flapper may be increased past a stress threshold by applying pressure in a first direction, wherein the first direction may be downhole. This pressure translates forces to stress points via the flapper.

(38) At operation 630, based on the stress threshold and pressure applied to the stress points via the flapper, an upper portion of the housing may be decoupled from the lower portion of the housing while both the upper portion and the lower portion are encompassed by an insert. While both the upper portion and the lower portion are encompassed by the insert, an area above the flapper may still be isolated from an area below the flapper even after the upper portion and the lower portion are decoupled from each other.

(39) At operation 640, fluid may flow or pressure increase in the second direction and interface with the flapper positioned within the insert.

(40) At operation 650, based on the fluid flowing in the second direction the flapper, the flapper pin and the upper portion of the housing may flow in the second direction and no longer be engaged or interfaced with the insert. This may allow fluid to flow through the insert and the lower portion of the housing stay engaged with the insert.

(41) FIG. 7 depicts a downhole tool 700, according to an embodiment. Elements depicted in FIG. 7 may be described above, and for the sake of brevity a further description of these elements is omitted.

(42) As depicted in FIG. 7, downhole tool 700 may be a frac plug with upper slips 710, upper cone 720, packing element 730, lower cone 740, and lower slips 750. In other embodiment slips 710 may be eliminated.

(43) The upper slips 710 may be configured to radially expand/break based on the movement of the upper cone 720. The upper cone 720 may be positioned between the upper slips 710 and the packing element 730. The upper cone 720 may be configured to engage with the upper slips 710 to radially expand/break the upper slips 710. In embodiments, the upper cone 720 may be coupled to the mandrel via breakable threads or any other breakable coupling mechanism. The threads on the upper cone may be configured to directly couple the upper cone 720 with the mandrel of the frac plug to maintain the upper cone 720 in a non-deployed state even with incidental movement from the packing element 730.

(44) The packing element 730 may be a packer/rubber/elastic material that is configured to compress and radially expand across the wellbore. The packing element 730 may be configured to compress based on a pressure differential/forces across the packing element 730 caused by the upper cone 720 and the lower cone 740 trapping these pressures/forces during frac plug setting and/or while fracing operation above the frac plug after setting.

(45) The lower cone 740 may be positioned between the packing element 730 and the lower slips 750. The lower cone 740 may be configured to engage with the lower slips to radially expand or break the lower slips. In embodiments, the lower cone 740 may be coupled to the mandrel via breakable threads or any other breakable coupling mechanism. The threads on the lower cone 740 may be configured to directly couple the lower cone 740 with the mandrel of the frac plug to maintain the lower cone 740 in a non-deployed state even with incidental movement from the lower slips 750 or packing element 730.

(46) The lower slips 750 may be positioned adjacent to the lower cone 740 and cap 760. The lower slips 750 may be configured to radially expand or break based on the movement of the lower cone 740. In embodiments, the lower slips 750 may be coupled to the mandrel via breakable threads or any other breakable coupling mechanism, The threads on the lower slips 750 may be configured to directly couple the lower slips 750 with the mandrel of the frac plug to maintain the lower slips 750 in a non-deployed state even with incidental movement from the lower cone 740.

(47) As further depicted in FIG. 7, insert 120, housing 130, and flapper 135 may be configured to be mounted on a proximal end of downhole tool 100, between the proximal most end of downhole tool 700 and upper slips 710. This may allow the elements of downhole tool 700 to not be activated until communication is established across housing 130. In other embodiments, insert 120, housing 130, and flapper may be configured to be mounted on a distal end of the downhole tool 100.

(48) Although the present technology has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred implementations, it is to be understood that such detail is solely for that purpose and that the technology is not limited to the disclosed implementations, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present technology contemplates that, to the extent possible, one or more features of any implementation can be combined with one or more features of any other implementation.

(49) Reference throughout this specification to “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, “one example” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it is appreciated that the figures provided herewith are for explanation purposes to persons ordinarily skilled in the art and that the drawings are not necessarily drawn to scale.