Improved Packer Bridge Plug with Removable/Dissolvable Ball Seat

BACKGROUND OF THE INVENTION

[001] This application claims the benefit of U.S. Provisional Application 62/052,054, filed Sep. 18, 2014, entitled "Improved Packer Bridge Plug with Removable/Dissolvable Ball Seat," which is incorporated herein by reference.

1. FIELD OF THE INVENTION [002] The present invention relates to a bridge plug packer having a ball seat and packer element for sealing one zone of a well from another, wherein the ball seat is dissolvable, resizeable, moveable or removable.

[003] In the process of fracking, it is expensive to run tools into and out of the well. It is therefore desirable to run in tools that can serve multiple purposes during the fracking process. The present invention in at least one embodiment is to a packer tool that can be used to seal a well bore and when the ball is removed presents only a small resistance to the production flow up through the plug. SUMMARY OF THE INVENTION

[001] Accordingly, it is a principal object of a preferred embodiment of the invention to provide a packer plug that can be tripped into a particular location in a well bore and set using slips or slip rings and packer elements. The plug presents little flow resistance because of its wide inner diameter throat through the mandrel. A ball seat at an upper end allows for the sealing of the interior passage. The ball can be flowed upward or dissolved, but preferably the ball seat can be dissolved or relocated to remove the seal with the ball and to allow flow through the plug.

[002] It is another object of the invention to provide a selectively sealable down hole tool that can be sealed and unsealed during the fracking process without having to trip the entire tool back up the well bore.

[003] It is a further object of the invention to a bridge plug for use with a removable ball or with a dissolvable, changeable or moveable ball seat to allow production flow through the tool without requiring removal of the tool.

[004] Still another object of the invention is to provide a down hole tool that can be set with a setting tool to set one or more bridge plugs in series to isolate a number of zones in a well bore which can be selectively unsealed to allow production flow through the tool.

[005] It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. [006] These and other objects of the present invention will be readily apparent upon review of the following detailed description of the invention and the accompanying drawings. These objects of the present invention are not exhaustive and are not to be construed as limiting the scope of the claimed invention. Further, it must be understood that no one embodiment of the present invention need include all of the aforementioned objects of the present invention. Rather, a given embodiment may include one or none of the aforementioned objects. Accordingly, these objects are not to be used to limit the scope of the claims of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[007] Fig. 1 is a cross-sectional view of a bridge plug packer and run in or setting tool according to at least one embodiment of the invention with a run in tool.

[008] Fig. 2 is a cross-sectional view of the bridge plug according to the embodiment of Figure 1 having a first, dissolvable seat.

[009] Figs. 3 and 4 are cross-sectional views of the bridge plug according to a further embodiment having an expandable seat.

[010] Fig. 3B is a top plan view of a ball seat according to at least one embodiment of the invention.

[011] Fig. 5 is a cross-sectional view of the bridge plug according to a further embodiment having expansion or slip rings.

[012] Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(s)

[013] The present invention is to a novel method of allowing a ball to pass through a bridge plug when using a non-dissolvable ball.

[014] Figure 1 shows a packer tool 1 12 connected to a setting gun 148 by an adapter 162. The adapter is attached to setting mandrel 150. The setting mandrel is attached to the packer tool 1 12 by shear ring 154 during run in. A cap 159 may be connected to the end of the tool to prevent flow therethrough during run in.

[015] The setting gun or other activator ("packer activator") allows the packer tool to be compressed when the packer tool is lowered in a well bore to the proper depth. Compression of the tool allows the slips 1 16 to engage the inner wall of the casing (not shown) surrounding the tool and to grip hold the tool in place with the frictional teeth of the slips. Further compression drives the upper cone further behind into the slips, levering the slips into further engagement with the tubing. The slips could be replaced by expansion rings ("slip rings") such as that shown in copending application 14/857,243, filed 9/17/2015 to George E. Allis, entitled "Improved Packer Bridge Plug with Slips," which is incorporated herein by reference.

[016] As the packer tool is further compressed, the packer element 1 18 is driven outwardly by rigid retaining rings 124 and by rings 120 compressing the packer element. The packer element is preferably rubber or similar material to form a fluid barrier separating the zone above the packer from the zone below the packer around the outside of the tool. This allows for separate zones within the well bore to be selectively separated from each other. Sealing of the inner chamber that runs the length of the interior of the tool is selectively sealed by ball 170 as described below. Further compression of the tool breaks the shear pins or other device attaching the shear ring to the setting tool 148. With the shear ring and friction cap 159, the setting tool may be released. Appropriate collets 152 or other devices allow the setting tool to be removed through the body of the packer tool.

[017] With the setting tool removed, the through passage of the packer tool may be selectively resealed by dropping a ball 170 (Figure 2) on top of the tool to seal the upper edge of the packer tool. With the ball in place, downward flow is prevented from passing the zone above the packer tool to the zone below the packer tool but around the tool by the packer element and through the tool by the ball. After fracking or other operations are performed, the ball preferably dissolves or is otherwise removed from the packer tool. Production may then occur by pumping fluid upwardly through the packer tool. As described above the collet arms of the packer tool also serve an additional function in that if a ball were pumped upwardly, it would rest on the fingers of the collet 14 and would still allow ample fluid between the arms of the collet.

IMPROVED BALL REMOVAL EMBODIMENT [018] According to a preferred embodiment of the present invention, the handling of the ball during production is shown by using a dissolvable, moveable, removable or expandable ball seat. Although the collet arms allow production flow past the ball through the "gaps" between the collet arms, it would be preferable not to have a ball at all to interrupt the flow during production. Currently dissolvable balls are used to remove the ball after its use is completed. However, dissolvable balls have their own problems and can be very expensive costing sometime $1500-1800 each.

[019] As shown in Figures 2-4, it would be preferable to pump the ball up instead of dissolving the ball or leaving it in place, especially when multiple packers are involved.

[020] In operation, an operator would run in a packer bridge plug ("packer tool") into place, or example using a wireline setting gun. The plug would be set and a zone would be perforated. The setting equipment would be removed from the well bore as described above and then a ball would be pumped into place to seal the zone so that fracturing could occur addressing only that interval. The process would then be repeated for as many intervals as you want to fracture in the toe of the well bore. At this point you will switch to a packer bridge plug having composite bridge plugs or coil tubing frac sleeves or any other fracking system by running in the improved bridge plugs for any added stages in the upper well bore section using for example progressively larger balls from the lowest packer tool to the highest packer tool. If composite plugs are run you will then drill them out and start flowing the well. According to the present invention, neither composite plugs or dissolvable balls are required as a moveable, expandable or dissolvable seat allows the use of normal steel or other material balls to flow downwardly or upwardly at the appropriate moment without drilling.

[021] Figure 2 shows an improved packer bridge plug with a dissolvable ball seat 214. During production ball 216 would already be removed, but a smaller ball would be flowed from the lower end upwardly until it abutted the lower part of the ball seat 214. At this point, the seat needs to be removed, dissolved, or otherwise adjusted so that the ball can continue its journey upward. The seat may be made of a dissolvable mater such as PLA or PGA dissolvable plastic. The seat may simply be shear pinned (Fig. 3) in place and flowed upward with the ball, preferably dissolving as it continues upward. However, a simple shear pinning such as this may be breached when the setting equipment is removed. The use of the term "dissolvable" in this application refers to materials that are dissolvable in a period of seconds to hours in a typical fluids such as water or hydraulic fluids.

[022] Preferably, the shear pin 21 1 is breached only after the setting tool is removed as shown in Figures 3-4. One way to accomplish this is by increasing the shear pin strength to ensure that the setting tool cannot breach the pin. The ball pumped into place for fracturing can withstand much more pressure than the setting tool is likely to put on the seat. However, these two will act in different directions on the seat. Therefore, it is preferably that the ball breach the shear pin while pressing the seat down and then pressing the seat into a first position where the seat maintains its shape. One way to do this is by having a variable wall (220, 218) in the seat as shown in Figure 2. When the wall is narrower and constricts the ball seat (i.e., in the position shown in Fig. 3), the ball seat cannot expand. When the wall is wider and does not constrict the ball seat (i.e., in the position shown in Figure 4), the ball seat can expand to have an larger inner diameter to pass a larger ball therethrough. The ball seat 1 15 can have a cut, slot or weakened area 1 19 (Figure 3B) to allow the ball seat to expand radially to fill the available area. The ball seat may start as a larger circle (or C shape) and may be compressed to the smaller size so that it "springs" outwardly when the pressure is released about the ball seat.

[023] As hydraulic pressure is increased above the ball, the ball will press the seat downward onto ledge 218, allowing the seat to shear the pin 21 1 , while not allowing the seat to expand or contract. The seat now abutting ledge 218 will thus continue to act to prevent the ball 216 from moving downward, even though the shear pin has been breached. However, now when a ball is pumped upward, the seat can either removed entirely from the plug, or is more preferably moved into a larger diameter holding area 220. A cut 1 19 (Figure 3B) in the seat ring will allow the seat to expand when the ring passes into the larger diameter bore in the tool. A smaller diameter ridge or wall at the top will prevent the ring from exiting the tool and allow it time to expand into the larger bore 220. In this way, a large diameter throat is maintained in the packer tool for production while not requiring dissolvable balls, which can cost upwardly of $1500 each. With the ball seat removed, multiple balls can be pumped sequentially downwardly or upwardly through the now open packer tool.

[024] Pressure from the ball being pumped upward through the seat may also encourage the seat to expand into the available area in bore 220. The seat may be made of cast iron, plastic or other metal. The seat may also be biased by springs or other materials into the preferred area.

[025] The seat ring is preferably a composite material. It may be made from PGA material, but can also be made from magnesium or magnesium hybrid material or magnesium proprietary material supplied by, for example, PARKER INDUSTRIES. The material can also be made from PLA or any other material that dissolves in a reasonable amount of time for standard ball drop fracturing jobs.

[026] While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains and as maybe applied to the central features hereinbefore set forth, and fall within the scope of the invention and the limits of the appended claims. It is therefore to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the