The present disclosure relates generally to fracturing and gravel packing systems and, more particularly (although not necessarily exclusively), to methods and assemblies for proppant placement in a pay zone of a wellbore using a controlled reverse flow.
Fracturing and gravel packing (commonly known as “frac packing”) is a technique combining a fracturing process (e.g., hydraulic fracturing) and a gravel packing process that may be used to complete a wellbore. For example, hydraulic fracturing may be used to stimulate the production of hydrocarbons from subterranean formations penetrated by a wellbore or to bypass damage near the wellbore. A fluid may be pumped through the wellbore and into a zone of a formation to be stimulated at a rate and pressure such that fractures are formed and extended into the zone. The gravel packing process following the fracturing treatment may allow for placing proppant around a screen in the wellbore to exclude formation sand from entering the wellbore along with the produced fluids. The proppant may function to prevent the fractures in the zone from closing, thereby providing conductive channels in the formation through which produced fluids can readily flow to the wellbore.
Certain aspects and examples of the present disclosure relate to systems and method for treating a pay zone adjacent to a wellbore using a reverse frac pack treatment system to control the expansion and shape of the pay zone. In some aspects, the pay zone may include formations adjacent to the wellbore including hydrocarbons. The frac pack treatment system may include a treating tube that may be positioned in a wellbore to create two passages for injecting fluid into the wellbore to fracture and expand the pay zone. In some aspects, the first of the two passages may be internal to the treating tube and the second passage may be an annulus between an external surface of the treating tube and a casing of the wellbore. The passages may be isolated from each other using one or more isolation devices (e.g., packers, plugs, etc.) to prevent fluid in one passage from leaking into the other. Fluid may be routed through one of the passages to fracture a zone adjacent to the wellbore and uphole or downhole of the pay zone. The fluid may be injected into the zone to create additional fractures such that the zone expands towards the pay zone. Fluid may be routed through the second of the two passages and injected into the pay zone, further expanding the pay zone to a desired size or shape.
Proppant may be routed through the first passage and into the expanded pay zone to deposit the proppant into the fractures created by the fluid. As the proppant is deposited into the pay zone through the first passage, the flow of the fluid through the second passage may be reversed such that the fluid injected into the pay zone may flow out of the pay zone and toward the surface of the wellbore through the second passage. The reverse flow of the fluid in the second passage may allow the placement of the proppant in the fractures of the pay zone to be controlled, thereby controlling the size and shape of the pay zone. In some aspects, a screen may be positioned across an opening of the pay zone. The screen may allow the fluid to flow out of the pay zone through the opening, but may prevent proppant in the pay zone from departing the pay zone through the opening.
The use of a reverse frac pack treatment system according to some aspects may allow for a placement of proppant in the pay zone with minimal equipment to control a flow back of the fluid in the pay zone. For example, a single treating tube may be positioned in the wellbore to create two passages, one of which may allow for a bi-directional flow of the fluid into and out of the pay zone. Additionally, the system according to some aspects may further allow control in the formation of the pay zone. For example, the system may be configured to allow the pay zone to be initially expanded from above or below the pay zone. Further, the system may allow the pay zone to be expanded from multiple points of entry into the pay zone via the passages created by the treating tube to expand the pay zone into a desired shape or geometry and place proppant in the pay zone in a desired manner.
The terms “inner,” “outer,” “internal,” “external,” “interior,” “exterior,” and “between,” as used in the present disclosure may refer to a radial orientation toward or away from the center of the wellbore unless otherwise stated. The terms “uphole,” “downhole,” “upward,” “downward,” “above,” and “below,” as used in the present disclosure may refer to an axial orientation toward or away from the surface unless otherwise stated.
Various aspects of the present disclosure may be implemented in various environments.
In some aspects, a reverse frac pack treatment system may include a treating tube 110. The treating tube 110 may include any work string or tubing string suitable to convey a treatment in the wellbore 102. The treating tube 110 may be positioned in the wellbore 102 to create passages 112, 114. The passage 112 may be internal to the treating tube 110 and the passage 114 may be external to the treating tube 110, as shown in
The reverse frac pack treatment system may also include one or more isolation devices 116. The passages 112, 114 may be isolated by an isolation device 116 to isolate the passages 112, 114 from one another. Isolation of the passages 112, 114 may allow the fluid flowing through the passage 112 to be separated from the fluid flowing through the passage 114. In some aspects, the separation of the fluid flowing in the passages 112, 114 may allow for a controlled injection or treatment of the wellbore 102. Non-limiting examples of isolation devices 116 may include packers, balls, plugs, bridge plugs, and wiper plugs. In some aspects, the isolation device 116 may be positioned in the passage 114 as shown in
The casing 106 in the downhole portion of the wellbore 102, proximate to the downhole opening of the passage 112, may include an interval having perforations 118. In some aspects, the perforations 118 may include one or more cavities or other openings in the casing 106 created by a perforation tool, such as a perforation gun. In some aspects, the perforations 118 may be positioned in the casing 106 to define an entry point for a fracturing zone in which fluid may be injected to fracture a formation adjacent to the wellbore 102. The perforations 118 are positioned below the pay zone 108 to allow the fracturing zone to be created and expanded toward to the pay zone 108 in an uphole direction. A screen 120 may be positioned uphole of the perforations 118. The screen 120 may be positioned along a cavity in the casing 106 and across an opening to the pay zone 108 created by the cavity. In some aspects, the screen 120 may include a sand control screen. In additional aspects, the screen may include a series of wire screen meshes or other material having small holes, slotted pipe, or other openings to allow certain fluids to flow between the passage 114 and the pay zone 108. The screen 120 may be positioned across the pay zone 108 as shown in
In some aspects, the passages 112, 114 may be communicatively coupled to pressure-gauge assemblies 122, 124, respectively. In some aspects, the pressure-gauge assemblies 122, 124 may be positioned in the wellbore 102. In other aspects, the pressure-gauge assemblies 122, 124 may be positioned at the surface 104 of the wellbore 102. The pressure-gauge assemblies 122, 124 may be coupled to the passages 112, 114 via one or more suitable communication lines or via a wireless connection. In one example, the pressure-gauge assemblies 122, 124 may include sensors positioned in the passages 112, 114, respectively. The sensors may be connected to a processing device positioned at the surface 104 of the wellbore 102 and configured to interpret the readings of the sensors to determine a real-time measurement of the pressure in the respective passages 112, 114. In some aspects, the pressure in the passages 112, 114 may indicate or correspond to a condition in the pay zone 108 or a stage in the frac pack treatment process.
For example,
In some aspects, the treating fluid 200 may continue to be injected into the fracturing zone 202 solely through the passage 112 to further expand the fracturing zone 202 outward, away from the wellbore 102. Alternatively, treating fluid 200 may also be routed into the pay zone 108 through the passage 114 to expand the pay zone 108 as shown in
In
In some aspects, the flow may be reversed in a manner to control the flow back of the treating fluid 200 from the pay zone 108 into the passage 114 and towards the surface. In some aspects, the flow may be reversed in any known manner, including, but not limited to manipulation of a valve or fluid pump connected to the passage 114. In additional and alternative aspects, reversing the flow of the treating fluid 200 through the passage 114 may be passively (or semi-passively) performed by discontinuing the flow of the treating fluid 200 toward the pay zone 108. The proppant 500 may be deposited into the pay zone 108 in a manner to displace the treating fluid 200 in the pay zone 108 and cause the treating fluid 200 to flow back toward the surface 104 of the wellbore 102 through the passage 114.
The pressure-gauge assembly 122 may continue to indicate a fracturing pressure in the passage 112. In some aspects, the pressure in the passage 112 may be slightly decreased in comparison to the pressure in the passage 112 during fracturing of the pay zone 108 by the treating fluid 200 as shown in
The proppant 500 may continue to be routed through the passage 112 and deposited in the fractures of the pay zone 108 as shown in
In
Although the reverse frac pack treatment process is described as expanding a pay zone from a fracturing zone below the pay zone, the process may be similarly performed by expanding the pay zone from a fracturing zone above the pay zone. For example,
The treating tube 110 may be positioned in the wellbore 102A as described with respect to
The treating tube 110 may be positioned in the wellbore 1028 to create the passages 112, 114. A downhole end of the treating tube 110 may be positioned internal to the isolation device 1010 to establish isolation between the passages 112, 114. The reverse frac packing treatment process may proceed similar to the process described with respect to
In some aspects, systems and methods may be provided according to one or more of the following examples:
A method may include positioning a treating tube in a wellbore to create a first passage and a second passage. The method may also include isolating the first passage from the second passage. The method may also include routing treating fluid through the first passage and into a fracturing zone adjacent to the wellbore to expand the fracturing zone toward a pay zone. The method may also include routing proppant through the first passage and into the fracturing zone. The method may also include reversing a direction of flow in the second passage to allow the treating fluid in the pay zone or the fracturing zone to flow into the second passage through a screen positioned adjacent to the pay zone.
The method of Example #1 may feature the first passage being internal to the treating tube and fluidly coupled to the fracturing zone through a perforation in a casing of the wellbore. The second passage may be an annulus between the treating tube and the casing of the wellbore and may be fluidly coupled to the pay zone through the screen.
The method of Example #1 may feature the first passage being an annulus between the treating tube and the casing of the wellbore and being fluidly coupled to the pay zone through the screen. The second passage may be internal to the treating tube and may be fluidly coupled to the fracturing zone through a perforation in a casing of the wellbore.
The method of Examples #1-3 may also include routing additional treating fluid through the second passage and into the pay zone to generate an expanded pay zone including the pay zone and the fracturing zone. The method may also feature reversing the direction of flow in the second passage to include allowing the treating fluid to exit the expanded pay zone through the screen.
The method of Examples #1-4 may feature isolating the first passage from the second passage to include positioning an isolation device in the second passage and uphole of a perforation in a casing of the wellbore. The method may also feature routing the treating fluid through the first passage and into the fracturing zone to include routing the treating fluid through the perforation.
The method of Example #5 may also include positioning the screen across a second perforation uphole of the isolation device. The method may also feature reversing the direction of flow into the second passage further to include allowing the treating fluid to flow into the second passage through the second perforation.
The method of Example #6 may feature positioning the screen across the second perforation to include coupling the screen to the isolation device and coupling the screen to a second isolation device positioned uphole of the second perforation.
The method of Examples #1-4 may feature isolating the first passage from the second passage to include positioning an isolation device in the first passage and downhole of a perforation in a casing of the wellbore. The method may also feature routing the treating fluid through the first passage and into the fracturing zone to include routing the treating fluid through the perforation.
The method of Example #8 may also include positioning the screen across a second perforation downhole of the isolation device. The method may also feature reversing the direction of flow into the second passage further to include allowing the treating fluid to flow from the pay zone into the second passage through the second perforation.
the method of Example #9 may feature positioning the screen across a second perforation to includes coupling the screen to the isolation device and coupling the screen to a second isolation device positioned downhole of the second perforation.
The method of Examples #1-10 may also include routing additional treating fluid through the second passage and into the pay zone at the same time that the treating fluid is routed through the first passage.
The method of Examples #1-11 may also include adjusting a pressure in the first passage to control a placement of the proppant in the fracturing zone or the pay zone.
A system may include a treating tube positionable in a wellbore to define (i) a passage internal to the treating tube and (ii) an annulus external to the treating tube. The passage may include a downhole opening positionable in the wellbore to allow a flow of treating fluid and proppant through a perforation in a casing of the wellbore downhole of a pay zone. The system may also include an isolation device positionable in the annulus to allow a bi-directional flow of additional treating fluid into the pay zone and out of the pay zone through a screen positioned across an opening of the pay zone.
The system of Example #13 may feature the isolation device being further positionable uphole of the perforation and downhole of the screen.
The system of Examples #13-14 may feature the screen being couplable to the isolation device and positionable in the annulus across the opening of the pay zone. The opening may include a second perforation in the casing of the wellbore uphole of the perforation.
The system of Examples #13-15 may feature the isolation device including a bridge plug having a valve internal to the bridge plug and closable in response to the treating tube being removed from the wellbore.
A system may include a treating tube positionable in a wellbore to define (i) a passage internal to the treating tube and (ii) an annulus external to the treating tube. The passage may include a downhole opening positionable proximate to a pay zone to allow a bi-directional flow of treating fluid into the pay zone and out of the pay zone through a screen positioned across an opening of the pay zone. They system may also include an isolation device positionable in the annulus to allow a flow of treating fluid and proppant through a perforation in a casing of the wellbore uphole of the pay zone.
The system of Example #17 may feature the isolation device being further positionable downhole of the perforation and uphole of the screen.
The system of Examples #17-18 may feature the screen being couplable to the isolation device and positionable in the annulus across the opening of the pay zone. The opening may include a second perforation in the casing of the wellbore downhole of the perforation.
The system of Examples #17-19 may also include one or more pressure-gauge assemblies communicatively coupled to the passage and the annulus to monitor pressure in the passage and the annulus.
The foregoing description of the examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the subject matter to the precise forms disclosed. Numerous modifications, adaptations, uses, and installations thereof can be apparent to those skilled in the art without departing from the scope of this disclosure. The illustrative examples described above are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts.
Filing Document | Filing Date | Country | Kind |
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PCT/US2015/058584 | 11/2/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/078667 | 5/11/2017 | WO | A |
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Number | Date | Country | |
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