Patent Application
20180106129
The embodiments described herein relate to a plug having a valve that permits fluid flow in both directions through the plug, but impedes or resists the flow in one direction with respect to the flow in the other direction. The valve permits the fracturing of a portion of a wellbore without the need to pump a plug, such as a ball, down the wellbore to block fluid flow to increase pressure within the wellbore.
Natural resources such as gas and oil may be recovered from subterranean formations using well-known techniques. Wellbores, both vertical and horizontal, may be drilled into a formation. After formation of the wellbore, a string of pipe, e.g., casing, may be run or cemented into the wellbore. Hydrocarbons may then be produced from the wellbore.
In an attempt to increase the production of hydrocarbons from the wellbore, the casing is often perforated and fracturing fluid is pumped into the wellbore to fracture the subterranean formation. Hydraulic fracturing of a wellbore has been used for more than 60 years to increase the flow capacity of hydrocarbons from a wellbore. Hydraulic fracturing pumps fluids into the wellbore at high pressures and pumping rates so that the rock formation of the wellbore fails and forms a fracture to increase the hydrocarbon production from the formation by providing additional pathways through which reservoir fluids being produced can flow into the wellbore.
One method of fracturing multiple zones in a wellbore is to use multiple ported collars in combination with sliding sleeve assemblies. The sliding sleeves are installed on the inner diameter of the casing and/or sleeves and can be held in place by shear pins. In some designs, the bottom most sleeve is capable of being opened hydraulically by applying a differential pressure to the sleeve assembly. After the casing with ported collars is installed, a fracturing process is performed on the bottom most zone of the well. This process may include hydraulically sliding sleeves in the first zone to open ports and then pumping the fracturing fluid into the formation through the open ports of the first zone. After fracturing the first zone, a plug, which may be a ball, is dropped and/or pumped down the well. The ball hits the next sleeve up from the first fractured zone in the well and thereby opens ports for fracturing the second zone. After fracturing the second zone, a second ball, which is slightly larger than the first ball, is dropped to open the ports for fracturing the third zone. This process is repeated using incrementally larger balls to open the ports in each consecutively higher zone in the well until all the zones have been fractured. However, because the well diameter is limited in size and the ball sizes are typically increased in quarter inch increments, this process is limited to fracturing only about 11 or 12 zones in a well before ball sizes run out. In addition, the use of the sliding sleeve assemblies and the packers to set the well casing in this method can be costly. Further, the sliding sleeve assemblies and balls can significantly reduce the inner diameter of the casing, which is often undesirable. After the fracture stimulation treatment is complete, it is often necessary to mill out the balls and ball seats from the casing.
Additional disadvantages of the current system may exist. For example, it may take a considerable amount of time to pumping a ball to down the wellbore to open the sliding sleeve of each production zone to be fractured. A system that may be used to fracture a production zone without the use of a ball may be beneficial.
The present disclosure is directed to plug having a valve that permits fluid flow in both directions through the plug, but inhibits the flow in one direction with respect the flow in the other direction and method of use that overcomes some of the problems and disadvantages discussed above.
One embodiment is a plug comprising a body and at least one sealing element positioned on an exterior of the body, the sealing element being configured to create a seal between the body and a portion of a wellbore. The plug comprises a flow path through an interior of the body and a valve positioned along the flow path. The valve permits fluid to fluid in a first direction through the flow path and permits fluid to flow in a second direction through the flow path, wherein the valve inhibits the flow of the fluid in the second direction with respect to the flow of fluid in the first direction.
The plug may comprise at least one setting element positioned on the exterior of the body configured to engage a portion of a wellbore. The first direction may be from below the body to above the body and the second direction may be from above the body to below the body. The valve may be a solid state device. The valve may be a Tesla valve. The valve may comprises a main flow path in communication with the flow through the interior of the body, a plurality of projections along the main flow path, and a plurality of secondary flow paths in communication with the main flow path. Fluid flowing in the first direction may flow substantially along the main flow path and the plurality of projections may divert fluid flowing in the second direction to flow through the plurality of secondary flow paths.
The valve may comprise a flow path through the valve having a plurality of chambers, the chambers being in communication with each other via a plurality of openings, wherein the openings are configured to permits substantially smooth fluid flow through the flow path in the first direction and the openings are configured to create turbulent flow within the chambers in the second direction. The valve may comprises a main flow path through the valve, the main flow path including a plurality of branches, wherein fluid flowing in the second direction through the main flow path through the valve is diverted to flow through the plurality of branches to impede the flow of fluid in comparison to fluid flowing in the first direction through the main flow path through the valve. The valve may comprise an insert that may be inserted into the body of the plug. The valve may be an integral part of the flow path of the body of the plug.
One embodiment is a method comprising providing a body having an internal flow path that may be positioned within a bore of the wellbore and providing a sealing element on an exterior portion of the body, wherein the sealing element selectively creates a seal between a portion of the wellbore and the body. The method comprises providing a valve in communication with the internal flow path of the body, the valve permitting fluid to flow in a first direction through the internal flow path and permitting fluid to flow in a second direction through the internal flow path, wherein the valve inhibits the flow of fluid in the second direction with respect to the flow of fluid in the first direction.
The method may comprise providing a main flow path through the valve in communication with the internal flow path and providing a plurality of projections along the main flow path. The method may comprise providing a plurality of secondary flow paths in communication with the main flow path, wherein fluid flowing in the first direction flow substantially along the main flow path and wherein the plurality of projections divert fluid flowing in the second direction to flow through the plurality of the secondary flow paths.
The method may comprise inserting an insert into the body, wherein the valve is formed in the insert. The method may comprise manufacturing the insert on a 3D printer. The method may comprise positioning the body within a wellbore, creating a seal between the body and a tubular within the wellbore, and pumping fluid down the wellbore, wherein the valve increases a pressure within the wellbore above the body. The method may comprise hydraulically fracturing a formation of the wellbore positioned above the body by continuing to pump fluid down the wellbore.
One embodiment is a valve for a plug comprising an inserted to be inserted into a plug body, the insert having a flow path in communication with a flow path through the body, wherein the insert flow path permits fluid to flow in a first direction through the insert flow path and permits fluid to flow in a second direction through the insert flow path, wherein the insert flow path inhibits the flow of fluid in the second direction with respect to the flow of fluid in the first direction.
The insert flow path may comprise a main flow path, a plurality of projections along the main flow path, and a plurality of secondary flow paths in communication with the main flow path. Fluid flowing in the first direction may flow substantially along the main flow path and the plurality of projections may divert fluid flowing in the second direction to flow through the plurality of the secondary flow paths. The insert may be a 3D printed part. The insert may comprise a flow path having a plurality of chambers, the chambers being in communication within each other via a plurality of openings, wherein the openings are configured to permit substantially smooth fluid flow through the flow path in the first direction and the openings are configured to create turbulent flow within the chambers in the second direction.
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 plug 100 may be, but is not limited to, a frac plug used to hydraulically fracture a wellbore formation. The plug 100, hereinafter referred to as a frac plug, includes a body 110 with a bore, internal flow path, or inner flow path 120, hereinafter referred to an internal flow path, which permits fluid to flow through the body 110 of the frac plug 100. The frac plug 100 includes a valve 200 having a main flow path 220 that is in fluid communication with the internal flow path 120 to permit fluid to flow through the frac plug 100 in a first direction, indicated by arrow A on
The frac plug 100 may include a slips 130 and cones 140 used to secure the frac plug 100 at a desired location within the wellbore. The slips 130 may be configured to engage a tubular, such as casing or a production tubular, positioned within a wellbore. As discussed above, the plug 100 may also be a packer configured to be positioned in an openhole wellbore. The frac plug 100 may include a sealing element 150 connected to the exterior of the body 110. The sealing element 150 may be actuated to create a seal between the exterior of the body 110 and a portion of the wellbore. When set within a wellbore with the sealing element 150 actuated, fluid may pass the frac plug 100 only through the internal flow path 120 of the frac plug 100 and the main flow path 220 of the valve 200. The number, configuration, and location of the slips 130, cones 140, and sealing element 150 are shown for illustrative purposes and may be varied depending on the application as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure.
The valve 200 of the frac plug 100 is configured to impede or provide higher resistance for the fluid flowing in one direction through the main bore 220 with respect to fluid flowing in the other direction through the main bore 220. For example, the valve 200 may be a Tesla valve that is configured to provide an increase flow resistance in one direction. As shown in
The increase in total distance traveled by fluid to exit the plug 100 in the second direction B may not be the only factor for having an increased flow resistance. For example, the secondary flow paths 240 may be designed so that the return portion 241 of the secondary flow path 240 creates turbulent flow within the main flow path 220. The return portion 241 may be designed to return the fluid to the main flow path 220 at an orientation opposing the direction of flow as shown in
The valve 200 may be an integral part of the frac plug 100. Alternatively, the valve 200 may be manufactured as an insert that may be inserted into the internal flow path 120 of the frac plug 100.
The second opening 422 may be configured to be larger in comparison to the first opening 421. The larger opening 422 in combination with the sloped interface with the first chamber 450A may cause the fluid flow to expand outward as it enters the chamber 450A. The outer recessed portions 452A of the chamber 450A in combination with the opening 455A may create turbulent flow within the valve 400 thus increasing the fluid flow resistance. The opening 455A between chamber 450A and chamber 450B may include an edge or protrusion 451A that diverts fluid flowing towards the first opening 421, but does not divert fluid flowing toward the second opening 422. Likewise, the other chambers 450B, 450C, and 450D may include recess portions 452B, 452C, and 452D also configured to cause turbulent flow. The leading edges 452B, 452C, and 452D may also divert a portion of fluid flowing towards the first opening 421, but not divert fluid flowing towards the second opening 422. The narrow main flow path 420 in combination with the smaller diameter of the first opening 421 may tend to form a smooth narrow flow of fluid flowing towards the second opening 422 as it enters the valve the valve 400 from the first opening 421. The smooth narrow flow of fluid may pass through the openings 455A, 455B, 455C, and 455D without substantial turbulence. Thus, the valve 400 may provide for fluid flow in both directions through the valve 400, but with one direction having a higher fluid flow resistance.
A first frac plug 100A is positioned below a first set of perforations 10A in the casing 6. Likewise, a second frac plug 100B is positioned below a second set of perforations 10B in the casing 6 and a third frac plug 100C is positioned below a third set of perforations 10C in the casing 6. Fluid may be pumped down the wellbore with the frac plugs 100A, 100B, and 100C in place to hydraulically fracture the wellbore formation 5 adjacent each of the perforations 10A, 10B, and 10C.
The higher resistance of fluid flow down of the third or upper frac plug 100C permits the pumping of fluid down the wellbore 1 to create a pressure increase above the frac plug 100C. Fluid can continue to be pumped down the wellbore 1 until the pressure is adequate to hydraulically fracture the formation 5 though the perforations 10C in the casing 6. Thus, the formation 5 may be hydraulically fractured without the need to pump a plug, such as a ball or dart, down the wellbore to be seated to create a seal or inhibit fluid flow, which potentially reduces the time required to fracture each zone. Further, the valve 200 of the frac plug 100C does permit the fluid to flow down through the frac plug 100C so that the formation 5 at second zone may be fractured through perforations 10B in the casing 6 due to the placement of the second frac plug 100B. Likewise, the placement of the first frac plug 10A permits the fracturing of the formation 5 via the perforations 10A. As discussed herein, the valves 200 in each of the frac plugs 100A, 100B, and 100C permits the flow of fluid upwards through the frac plugs 100A, 100B, and 100C. Thus, production of fluids from zones beneath each of the frac plugs 100A, 100B, and 100C may flow up the wellbore 1. The frac plug of the present disclosure may also be used to re-fracture a location that has been previously hydraulically fractured, if necessary.
The frac plug 100 having a valve 200, 300, or 400 of the present disclosure provides a solid state device that may permit the fracturing of a wellbore formation 5 without the need to drop a plug, such as a ball, down the wellbore or actuate a valve. The frac plug 100 having a valve 200, 300, or 400 of the present disclosure permits the production of fluids while positioned within the wellbore. Further, the pressure of a zone below a frac plug 100 having the valve 200, 300, or 400 of the present disclosure will not build up as the pressure will be release due to the upward flow of fluid through the frac plug 100. The number, location, and configuration of the frac plugs 100A, 100B, and 100C of
Although this disclosure 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 disclosure. Accordingly, the scope of the present disclosure is defined only by reference to the appended claims and equivalents thereof.
