Patent Application
20250003304
In the oil and gas industry fracturing operations are performed to establish communication between a formation and a wellbore for production. Fracturing technology relies on pumping high volumes of highly pressurized fracturing fluid down the wellbore to the formation, where the pressure of the fracturing fluid exceeds the formation breaking pressure, creating fractures. Fractures are stress dependent, such that propagation of fractures in the formation is controlled by stress orientation. As a result, fractures may propagate in directions that bypass of some hydrocarbons in the formation thereby reducing the rate of hydrocarbon production and/or the total hydrocarbon ultimately produced. A method of fracturing that prevents or reduces the amount of bypassed hydrocarbon is therefore desirable.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In general, in one aspect, embodiments relate to a method, including lowering a laser cutting tool into a wellbore drilled into a subsurface formation; where the laser cutting tool includes a tool body, a rotating cutting head positioned along the tool body, and an optical fiber extending through the tool body to the rotating cutting head; directing a laser beam through the optical fiber at a first power level to the rotating cutting head, directing the laser beam from the rotating cutting head in a radially outward direction to cut into the wellbore, and rotating the rotating cutting head while directing the laser beam in the radially outward direction from the rotating cutting head to cut a first groove in the wellbore.
In general, in one aspect, embodiments relate to a laser cutting tool including a tool body having a central axis, an optical fiber extending through the tool body, a rotating cutting head provided coaxially along the tool body, and a motor configured to rotate the rotating cutting head about the central axis independently from the tool body. The rotating cutting head includes a laser head disposed on a side of the rotating cutting head, the laser head comprising a laser exit, a rotational optics assembly positioned coaxially with an end of the optical fiber, the rotational optics assembly including a mirror facing the end of the optical fiber at an angle, an internal laser passageway extending in a radial direction between the rotational optics assembly and the laser exit, and an optical lens mounted transversely in the internal laser passageway.
In general, in one aspect, embodiments relate to a transverse fracturing system. The system includes a laser cutting tool, and a motor operatively connected to the laser cutting tool and configured to rotate the rotating cutting head about the central axis. The laser cutting tool includes a tool body having a central axis, and an optical fiber extending through the tool body, a rotating cutting head provided coaxially along the tool body, and and a rotational optics assembly positioned coaxially with an end of the optical fiber, where the rotational optics assembly is rotatable with the rotating cutting head. The rotating cutting head is rotational about the central axis and includes a laser head disposed on a side of the rotating cutting head, the laser head comprising a laser exit, an internal laser passageway extending through the rotating cutting head to the laser exit, and an optical lens mounted transversely in the internal laser passageway.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The size and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a fracture” includes reference to one or more of such fractures.
Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
It is to be understood that one or more of the steps shown in the flowchart may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope disclosed herein should not be considered limited to the specific arrangement of steps shown in the flowchart.
In the following description of
In one aspect, embodiments disclosed herein relate to a method of creating transverse fractures within a formation using a laser cutting tool. More specifically, embodiments disclosed herein relate to using a rotating cutting head, which may emit a controlled laser beam, to create a circular, or approximately circular, transverse fracture within a formation. In another aspect, embodiments disclosed herein relate to a transverse fracturing system which may be deployed to a formation, and which may be powered from a surface location. The transverse fracturing system may include a laser cutting tool with a rotating cutting head configured to create transverse fractures in a formation.
A hydraulic fracturing operation is performed in stages and on multiple wells that are geographically grouped. A singular well may have anywhere from one to in excess of forty stages. Typically, each stage includes one perforation operation, that may generate a plurality of adjacent perforations, and one pumping operation. While a perforation operation is occurring on one well, a pumping operation may be performed on the other well. As such,
The first well (102) and the second well (104) are horizontal wells meaning that each well includes a vertical section and a diverging section. The diverging section is a section of the well that is drilled at least eighty degrees from vertical. However, fracturing operations may be performed on vertical wells and less deviated wells and the well trajectory illustrated in
The first well (102) and the second well (104) are shown as requiring four stages, as an example. Both the first well (102) and the second well (104) have undergone three stages and are undergoing the fourth stage. The second well (104) has already undergone the fourth stage perforation operation and is currently undergoing the fourth stage pumping operation. The first well (102) is undergoing the fourth stage perforating operation and has yet to undergo the fourth stage pumping operation.
The perforating operation includes installing a wireline blow out preventor (BOP) (110) onto the first frac tree (106). A wireline BOP (110) is similar to a drilling BOP; however, a wireline BOP (110) has seals designed to close around (or shear) wireline (112) rather than drill pipe. A lubricator (114) is connected to the opposite end of the wireline BOP (110). A lubricator (114) is a long, high-pressure pipe used to equalize between downhole pressure and atmosphere pressure in order to run downhole tools, such as a perforating gun (116), into the well.
The perforating gun (116) is lowered into the first well (102) using the lubricator (114), wireline (112), and fluid pressure. In accordance with one or more embodiments, the perforating gun (116) is equipped with explosives and a frac plug (118) prior to being deployed in the first well (102). The wireline (112) is connected to a spool (120) often located on a wireline truck (122). Electronics (not pictured) included in the wireline truck (122) are used to control the unspooling/spooling of the wireline (112) and are used to send and receive messages along the wireline (112). The electronics may also be connected, wired or wirelessly, to a monitoring system (124) that is used to monitor and control the various operations being performed on the hydraulic fracturing site (100).
When the perforating gun (116) reaches a predetermined depth, a message is sent along the wireline (112) to set the frac plug (118) to seal the section of the well in the stage being performed. After the frac plug (118) is set, another message is sent through the wireline (112) to detonate the explosives, as shown in
As explained above,
The frac blender (138) blends the water, chemicals, and proppant to become the frac fluid (128). The frac fluid (128) is transported to one or more frac pumps, often pump trucks (140), to be pumped through the second frac tree (108) into the second well (104). Each pump truck (140) includes a pump designed to pump the frac fluid (128) at a certain pressure. More than one pump truck (140) may be used at a time to increase the pressure of the frac fluid (128) being pumped into the second well (104). The frac fluid (128) is transported from the pump truck (140) to the second frac tree (108) using a plurality of frac lines (136).
The fluid pressure propagates and creates the fractures (142) while the proppant props open the fractures (142) once the pressure is released. Different chemicals may be used to lower friction pressure, prevent corrosion, etc. The pumping operation may be designed to last a certain length of time to ensure the fractures (142) have propagated enough. Further the frac fluid (128) may have different make ups throughout the pumping operation to optimize the pumping operation without departing from the scope of the disclosure herein.
Through the fracturing process shown in
According to embodiments of the present disclosure, fracture bypassed zones may be prevented by using a laser cutting tool disclosed herein to form relatively uniform cuts through a surrounding formation. As described in more detail below, a laser cutting tool according to embodiments of the present disclosure may include one or more rotating cutting heads designed to direct a laser beam outwardly from the rotating cutting head as the rotating cutting head rotates within a well. In such manner, the laser beam may travel linearly into a surrounding formation as the rotating cutting head rotates, thereby forming a cut into the surrounding formation along a single plane transverse to the wellbore. Thus, unlike fractures (142) formed by conventional fracturing processes (e.g., by perforation guns (116)), which extend in multiple directions according to surrounding formation characteristics (e.g., stress concentrations, heterogeneities, and physical discontinuities in the rock), cuts formed by a laser cutting tool may be controlled in a single direction. According to embodiments of the present disclosure, a laser cutting tool may be lowered into a well to form cuts through a surrounding formation in the alternative to forming conventional fractures. In some embodiments, a laser cutting tool may be used to form cuts through a surrounding formation after forming conventional fractures (142), such as in the first well (102) shown in
The tool body (302) may be connected at an axial end to a wireline or coiled tubing (301) to be lowered into a well. In one or more embodiments, the tool body (302) may be configured to withstand high temperatures and high pressures, such as those typically associated with the fracturing process at a formation (107). An optical fiber (304) extends through the tool body (302) to the rotating cutting head (306), where an end of the optical fiber (304) may be connected to and/or held within the rotating cutting head (306). The optical fiber (304) may be configured to receive a laser beam and to emit the laser beam. In one or more embodiments, the laser beam may be generated at the surface and delivered to a rotating cutting head (306) via the optical fiber (304). In other embodiments, the laser beam may be generated in-situ at a downhole location.
A mechanical gear (319) may be secured between the rotating cutting head (306) and the tool body (302) to rotate the rotating cutting head (306) relative to the tool body (302) about a central axis (404). In one or more embodiments, the mechanical gear may be rotated by a motor (317) that is hydraulically or electrically powered. In some embodiments, such motor (317) may be provided in the tool body (302) and connected to a gear assembly (including one or more gears (319)) in the rotating cutting head to rotate the rotating cutting head (306). The rotating cutting head (306) may be coaxially aligned with the tool body (302), such that the rotating cutting head (306) may rotate about the central axis (404) of the tool body (302).
Further, according to embodiments of the present disclosure, a rotational optics assembly (313), such as shown in
In one or more embodiments, a rotational optics assembly (313) may be triangularly positioned between an end of the optical fiber (304) and an optical lens (308) in the rotating cutting head (306), where the rotational optics assembly (313) is configured to direct the laser beam (311) transmitted from the optical fiber (304) at an angle to the optical lens (308). Additionally, the rotational optics assembly (313) may be fixed within the rotating cutting head (306) in an axially aligned position with the optical fiber (304), such that the laser beam (311) may be continuously directed from the optical fiber (304) to the rotational optics assembly (313) as the rotating cutting head (306) (and thus also the rotational optics assembly (313)) rotates about the central axis (404). One skilled in the art may appreciate that various types and configurations of rotational optics assemblies may be used to transmit a laser beam from an optical fiber (304) at an angle to an optical lens (308) to allow the laser beam to be directed in a radial outward direction from the rotating cutting head (306) as the rotating cutting head (306) rotates about its central axis (404).
In some embodiments, a rotating cutting head (306) may be rotated with the tool body (302) about a common central axis (404). In such embodiments, a rotational optics assembly may be provided at a point of relative rotation between the rotating laser cutting tool and the laser beam source to allow transmission of the laser beam from a non-rotating portion of the optical fiber to a rotating portion of the optical fiber (304) as the entire laser cutting tool (300) rotates. For example, a laser cutting tool may be connected at an axial end to a downhole motor, where the rotational optics assembly may be provided at the axial end of the laser cutting tool. In such embodiments, the rotational optics assembly may be positioned proximate an axial end of a non-rotating optical fiber and configured to direct a laser beam from the non-rotating optical fiber to a coaxial rotating optical fiber that extends through and rotates with the laser cutting tool. For example, a laser beam may pass through the rotational optics assembly from a non-rotating optical fiber to a coaxial rotating optical fiber. As shown in
According to embodiments of the present disclosure, a rotational optics assembly may be configured to direct a laser beam from a non-rotating optical fiber at an angle outwardly from the optical fiber central axis or coaxial with the optical fiber central axis, depending on whether a laser cutting tool is designed to have a rotating cutting head that rotates independently from the tool body, or is designed to rotate entirely (where the rotating cutting head and tool body rotate together). A rotational optics assembly may be held in the laser cutting tool to rotate with the rotating cutting head (either when the rotating cutting head rotates independently from the tool body or when the rotating cutting head rotates with the tool body). The rotational optics assembly may be allowed to rotate while also receiving a laser beam emitted from an end of a non-rotating optical fiber by holding the rotational optics assembly axially aligned with the end of the non-rotating optical fiber but disjointed from the end of the non-rotating optical fiber (e.g., disconnected but adjacent to the optical fiber end or axially spaced apart from the optical fiber end, as shown in
In one or more embodiments, the optical lens (308) may be configured to shape, size, and/or orient the laser beam (311) from the optical fiber into a controlled laser beam (310), which may be directed through an internal laser passageway (312) and out of an exit (314) (an opening) provided through a laser head (307) on the rotating cutting head (306). For example, the optical lens (308) may shape the laser beam as either collimated, where the controlled laser beam (310) may have the same diameter as the laser beam, or focused, where the controlled laser beam (310) may have a smaller diameter than the laser beam.
The internal laser passageway (312) may extend through the rotating cutting head (306) in a radial direction between the central axis (404) of the laser cutting tool (300) and the exit (314) in the laser head (307). The laser head (307) (and exit (314)) is provided around a side of the rotating cutting head (306), such that as the rotating cutting head (306) is rotated, the laser head (307) of the rotating cutting head moves circumferentially around the laser cutting tool (300).
One or more cover lenses (316) may be arranged within the internal laser passageway (312) to transverse the internal laser passageway, e.g., including an outer cover lens located relatively closer to the exit (314) and an inner cover lens located relatively farther from the exit (314) of the rotating cutting head. The one or more cover lenses (316) may be arranged perpendicular to the controlled laser beam (310). In one or more embodiments, cover lenses (316) may be spaced at least 2″ apart from one another and from the optical lens (308). In one or more embodiments, the cover lenses (316) may be configured to protect the optical lens (308) and the optical fiber (304) from back reflection, dust, and debris.
An internal purging system (318) may be integrally formed with the rotating cutting head (306) and used to cool the optical lens (308) and the one or more cover lenses (316). The internal purging system (318) may include fluid openings oriented to direct a fluid onto the optical lens (308) and the cover lenses (316). Additional fluid nozzles (320) may be directed towards the cover lenses (316). In one or more embodiments, the additional fluid nozzles (320) may inject fluid parallel to the laser beam emitted from the rotating cutting head (306). Further, the number of additional fluid nozzles (320) may be selected to produce a desired flow rate. One or more external fluid nozzles (322) may be coupled to the circular laser tool (300) and may be positioned at the exit (314) of the rotating cutting head (306). The external fluid nozzles (322) may be configured to clear a path for the controlled laser beam (310) emitted by the rotating cutting head (306). More specifically, the external fluid nozzles (322) may clear any debris from the path of the controlled laser beam (310).
In one or more embodiments, the external fluid nozzles (322) may inject a gas or a liquid. The gas used, for example, may be an inert gas, such as nitrogen. The fluid source supplying the gas or liquid may be located at the surface. A flow path from the fluid source to the nozzles (320, 322, 318) in the rotating cutting head (306) may be provided through coiled tubing (301), the tool body (302), and the rotating cutting head (306) via fluidly connected passages through the assembly. In one or more embodiments, a laser cutting tool (300) may include one or more annular flow paths, which may fluidly connect flow passages between the tool body (302) and a rotating cutting head (306) while also allowing the rotating cutting head (306) to rotate relative to the tool body (302). In some embodiments, an entire laser cutting tool (300) may rotate (rotating the rotating cutting head (306) together with the tool body (302)). In such embodiments, one or more annular flow paths may fluidly connect flow passages between the laser cutting tool (300) and the coiled tubing (301) while also allowing the laser cutting tool to rotate.
In one or more embodiments, the fluid nozzles (320) and the external fluid nozzles (322) may inject either the same fluid or a different fluid depending on the application. For example, in embodiments where different fluids are used, the fluid nozzles (320) may inject a lighter fluid which can penetrate deeper into the formation and the external fluid nozzles (322) may inject a heavier fluid to control pressure in the wellbore (202).
Turning now to
The laser cutting tool (400) may be powered from the surface (105) by a laser power generator (406). In one or more embodiments, the laser power generator (406) may be a diesel generator configured to provide electric power to generate laser energy. The laser cutting tool (400) may have more than one rotating cutting head (306) arranged along a tool body (302). In one or more embodiments, multiple rotating cutting heads (306) may be powered by the same optical fiber (304). Each rotating cutting head (306) may be separated by a spacing (402). In some embodiments, the rotating cutting heads (306) may be evenly spaced. In other embodiments, the spacing (402) may vary depending on the formation (107) and production operations. In one or more embodiments, each rotating cutting head (306) may rotate about central axis (404) of the laser cutting tool (400). In one or more embodiments, the rotating cutting heads (306) may be centrally positioned within the wellbore (202) using a centralizer (not pictured) positioned along the tool body (302). In one or more embodiments, the laser cutting tool (400) may be pushed (e.g., on coiled tubing or lowered on a wireline) or pulled (e.g., on a borehole-tractor) from one depth to another.
When positioned in a selected location of the well (303), a laser beam may be generated by the laser power generator (406) and directed through the optical fiber (304) (which may be split into one or more portions to allow rotation of part of the optical fiber) to one or more of the rotating cutting heads (306) of the laser cutting tool (400). The laser beam may be focused through the rotating cutting head (306) into a controlled laser beam (310), which may be directed in a radially outward direction from an exit (314) of the rotating cutting head (306) into the formation (107) around the well (303). The controlled laser beam (310) may be continuously emitted from the rotating cutting head (306) in the radially outward direction as the rotating cutting head (306) rotates about the central axis (404). In such manner, the controlled laser beam (310) may form a controlled cut through the formation (107) along a plane transverse to the well (303).
For example,
Once the first circular hole (504) has been created, the power of the controlled laser beam (310) may increase to a second power level greater than the first power level to create a second hole (506), as shown in
Once the desired depth has been achieved through the process shown in
Initially in step S702, a laser cutting tool (300, 400) may be suspended in a borehole or a wellbore (202). In particular, the laser cutting tool (300, 400) may be lowered from a wellhead at the surface (105) into a well (such as the first well (102) or the second well (104)) to a subsurface formation (107). Specifically, the laser cutting tool (300, 400) may be lowered down the wellbore (202) to a desired fracturing location within the formation (107). In one or more embodiments, the laser cutting tool (300, 400) may include an optical fiber (304) with a first end (305), where the first end (305) is disposed in a rotating cutting head (306).
In step S704, a groove may be cut into the wall of the wellbore (202) using the laser cutting tool (300, 400). This may involve directing a laser beam from the first end (305) of the optical fiber (304). The laser beam may be generated by a laser with a first power level, where the laser is powered by a laser power generator (406) located at the surface (105) of the earth and transmitted downhole through an optical fiber enabled coiled tubing, onto which a tool body (302) may be secured. The laser beam may be received by an optical fiber (304), which may extend through the tool body (302). In one or more embodiments, the laser power generator (406) may supply a variable power to the laser cutting tool (300, 400), such that a lower power may first be supplied, following by a higher power. The laser may be connected to a second end of the optical fiber (304) and directed toward a wall of the wellbore (202).
A controlled laser beam (310) may be created using the laser cutting tool (300, 400). The intensity of the controlled laser beam (310) may depend on the intensity of the power supplied by the laser power generator (406). In one or more embodiments, creating the controlled laser beam (310) may include emitting a laser beam from the first end (305) of the optical fiber (304) into an optical lens (308), and shaping and sizing the laser beam using the optical lens (308) to produce the controlled laser beam (310).
In one or more embodiments, the groove may be, for example, the first hole (502). More specifically, the groove may be cut by rotating the rotating cutting head (306) while directing the laser beam from the first end (305) of the optical fiber (304) against the wall of the wellbore (202). The rotating cutting head (306) may be rotated either clockwise or counter-clockwise. A 360° rotation of the rotating cutting head (306) around the central axis (404) of the laser cutting tool (300, 400) may create the first circular hole (504). The first circular hole (504) may form the beginning of a transverse fracture (602). Cutting the groove may also include, for example, focusing the laser beam on the wall of the wellbore using an optical lens (308). Additionally, fluid may be pumped through at least one external fluid nozzle (322) to flush any debris or dust particles from the groove. This fluid may be, for example, a transparent fluid.
The method may further include increasing the power of the laser from the first power level to a second power level, where the second power level is greater than the first power level. The laser beam may then be directed from the first end (305) of the optical fiber (304) towards the wall of the wellbore. As such, the groove in the wall of the wellbore may be enlarged (along the first circular hole (504) path) using the laser beam.
The method described above may be repeated until a final circular hole is created and the transverse fracture (602) reaches a desired depth, where the diameter of the final circular hole is equal to the desired depth. Transverse fractures (602) may allow for radial flow of hydrocarbons from the formation (107) into the wellbore (202). Further, transverse fractures (602) may maximize flow (64) due to a larger reservoir contact that in traditional hydraulic fractures.
Embodiments of the present disclosure may provide at least one of the following advantages. Traditional hydraulic fracturing operations are characterized by propagating fractures, the formation of which is largely dependent on stress orientation. As such, there are many bypassed zones which exist, meaning that a significant volume of hydrocarbon potential within formation is not produced. Embodiments of the present disclosure employ a laser cutting tool for the creation of circular transverse fractures. Circular transverse fractures can be created and sized to a desired depth, covering all areas within a formation, effectively eradicating any bypassed zones which may have existed with the use of traditional methods. Further, creation of circular transverse fractures may increase flow from the formation to the wellbore due to maximized reservoir contact. Use of a high power laser, such as the controlled laser beam described herein, is a non-damaging technology which provides suitable stimulation for formation rock samples. This technology is waterless, has a small footprint, and does not require any chemicals, unlike traditional fracturing operations.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. Although multiple dependent claims are not introduced, it would be apparent to one of ordinary skill that the subject matter of the dependent claims of one or more embodiments may be combined with other dependent claims.
