Patent Application
20240352832
Not applicable.
Not applicable.
This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present invention. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
The present disclosure relates to the field of hydrocarbon recovery operations. More specifically, the disclosure relates to the completion of a well for the production of oil and gas. More specifically still, the inventions herein relate to a perforating gun assembly wherein the shots along the perforating guns may be selectively oriented.
In the drilling of an oil and gas well, a near-vertical wellbore is formed through the earth using a drill bit urged downwardly at a lower end of a drill string. After drilling to a predetermined depth, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular area is thus formed between the string of casing and the formation penetrated by the wellbore.
A cementing operation is conducted in order to fill or “squeeze” the annular area with cement along part or all of the length of the wellbore. The combination of cement and casing strengthens the wellbore and facilitates zonal isolation, and subsequent completion, of hydrocarbon-producing pay-zones behind the casing.
In connection with the completion of the wellbore, several strings of casing having progressively smaller outer diameters will be cemented into the wellbore. These will include a string of surface casing, one or more strings of intermediate casing, and finally a string of production casing. The process of drilling and then cementing progressively smaller strings of casing is repeated until the well has reached total depth (“TD”). In some instances, the final string of casing is a liner, that is, a string of casing that is not tied back to the surface.
Within the last two decades, advances in drilling technology have enabled oil and gas operators to “kick-off” and steer wellbore trajectories from a vertical orientation to a near-horizontal orientation. The horizontal “leg” of each of these wellbores now often exceeds a length of one mile, and sometimes two or even three miles. This significantly multiplies the wellbore exposure to a target hydrocarbon-bearing formation. The horizontal leg will typically include the production casing.
The wellbore 100 is completed with a first string of casing 120, sometimes referred to as surface casing. The wellbore 100 is further completed with a second string of casing 130, typically referred to as an intermediate casing. In deeper wells, that is wells completed 7,500 feet or more below the earth surface 105, at least two intermediate strings of casing will be used. In
The wellbore 100 is finally completed with a string of production casing 150. In the view of
It is observed that the annular region around the surface casing 120 is filled with cement 125. The cement (or cement matrix) 125 serves to isolate the wellbore from fresh water zones and potentially porous formations around the production casing 120.
The annular regions around the intermediate casing strings 130, 140 are also filled with cement 135, 145. Similarly, the annular region around the production casing 150 is filled with cement 155. However, the cement 135, 145, 155 is optionally only placed behind the respective casing strings 130, 140, 150 up to the lowest joints of the immediately surrounding casing strings. Thus, a non-cemented annular region 132 is typically preserved above the cement matrix 135; a non-cemented annular region 142 is typically preserved above the cement matrix 145; and a non-cemented annular region 152 is frequently preserved above the cement matrix 155.
In order to facilitate the recovery of hydrocarbons, particularly in low-permeability formations 115, the production casing 150 along the horizontal portion 156 undergoes a process of perforating and fracturing (or in some cases perforating and acidizing). Due to the very long lengths of new horizontal wells, the perforating and formation treatment process is carried out in multiple stages.
In one method, a perforating gun assembly 200 is pumped down the wellbore 100 towards the toe 154 at the end of a wireline 240. The perforating gun assembly 200 will include a series of perforating guns (shown at 210 in
After perforating, the operator will fracture the formation 115 through the perforations. This is done by pumping treatment fluids into the formation 115 at a pressure above a formation parting pressure. After the fracturing operation is complete, the wireline 240 will be raised and the perforating gun assembly 200 will be positioned at a new location (or “depth”) along the horizontal portion 156. A plug (such as plug 112 of
The process of setting a plug, perforating the casing, and fracturing the formation is repeated in multiple stages until the wellbore 100 has been completed, that is, the wellbore 100 is ready for production. The shots create clusters of perforations to create fracture complexity and to enhance fluid communication with the formation 115. The result is that multiple plugs 112 are set along the horizontal wellbore 156 during the completion process.
In order to provide perforations for the multiple stages without having to pull the perforating gun after each detonation, the perforating gun assembly 200 employs multiple guns 210 in series.
Each perforating gun 210 represents various components. These typically include a “gun barrel” 212 which serves as an outer tubular housing. An uppermost gun barrel housing 212 is supported by an electric wire (or “e-line”) 240 that extends from the surface 105 and that delivers electrical energy down to the perforating gun assembly 200. Each perforating gun 210 also includes an explosive initiator, or “detonator” (shown in phantom at 229).
In addition, each perforating gun 210 comprises a detonating cord (shown at 545 in
The perforating gun assembly 200 may include short centralizer subs 220. In addition, tandem subs 225 may be used to connect the gun barrel housings 212 end-to-end. Each tandem sub 225 comprises a metal threaded connector placed between the gun barrels 210. Typically, the gun barrel housings 212 will have female-by-female threaded ends (such as end 412 in
Further, an insulated connection member 230 connects the e-line 240 to the uppermost gun barrel 210. The e-line 240 extends upward to a control interface (not shown) located at the surface 105.
The perforating gun assembly 200 and its long string of gun barrels (the housings 212 of the perforating guns 210) are carefully assembled at the surface 105, and then lowered into the wellbore 100 at the end of the e-line 240. After the casing 150 has been perforated and at least one plug 112 has been set, the setting tool 160 and the perforating gun assembly 200 are taken out of the wellbore 100, and a ball (not shown) is dropped into the wellbore 100 to close the plug 112. When the plug 112 is closed, a frac slurry (e.g., a mixture of water, sand, and surfactant) is pumped by a pumping system down the wellbore 100 for fracturing purposes. For a formation fracturing operation, the pumping system will create downhole pressure that is above the formation parting pressure.
It is observed that when the operator sends the detonation signals downhole, the directions to which the shots are fired into the formation cannot be controlled; instead, only the depth at which the shots are fired is controllable. In this respect, when the operator releases a perforating gun string into the wellbore 100, the perforating gun assembly 200 may (and likely will) rotate as it gravitationally falls into the wellbore 100. As the assembly 200 is pumped across the heel 153 and through the horizontal portion 156, additional rotational movement may occur. However, the operator may desire that shots be fired not only at selected depths, but also at a selected orientation about the central axis of a generally horizontal wellbore. Specifically, operators may prefer that the perforations be formed vertically upward (a 0° orientation) or downward (a 180° orientation) perpendicular from the central axis of the wellbore. Alternatively, operators may prefer that the perforations be formed laterally outward (90° or 270° orientation) from the central axis of the wellbore. This urges the fractures to propagate outwardly from the wellbore 100 in the direction of the perforations.
A need exists for an improved perforating gun assembly with orienting capability allowing perforations in any desired orientation from 0° to 360° about the central axis of the wellbore. Further, a need exists for an improved method of aligning charges along a perforating gun assembly for use in a wellbore. Still further, a need exists for a method of avoiding frac hits by shooting aligned perforations in a specific desired direction which may be away from a parent wellbore.
A novel perforating gun assembly is first provided herein. The perforating gun assembly is arranged to enable the operator the ability to select the orientation in which shots may be fired downhole.
In one aspect, the perforating gun assembly first includes a gun barrel housing. The gun barrel housing has a first end, a second end, and a bore extending between the first and second ends. Thus, the gun barrel housing defines a tubular body.
The perforating gun assembly also includes a pair of tandem subs. Specifically, a tandem sub is placed at each of the opposing ends of the gun barrel housing. Each tandem sub has a pair of male threaded ends and a bore extending therein. The tandem subs are threadedly connected to the respective ends of adjacent gun barrel housings.
The perforating gun assembly also includes a rail system. The rail system resides within the gun barrel housing. The rail system comprises:
Uniquely, the perforating gun system provides for a bearing connection. In this respect, a first bearing member resides at a distal end of the first ballast while a second bearing member resides at a distal end of the second ballast. Each ballast member engages and rotates within the bore of a respective tandem sub. Thus, when the perforating gun assembly is pumped into the horizontal leg of a wellbore, the ballasts will rotate into a downward position, placing the shaped charges into desired orientations.
Beneficially, the rail system may be used to support the charges in lieu of using a so-called “charge carrier tube.” The charges may be inserted into the respective receptacles along the rail from either a forward side or a rearward side of the frame. Additionally, the ballasts may be connected to the rail at varying angles relative to the frame. In this way, shots may be fired within the horizontal section of a wellbore in a pre-selected orientation relative to the central axis of the wellbore.
A perforating gun system is also provided herein. The perforating gun system also includes a gun barrel housing. The gun barrel housing has a first end, a second end opposite the first end, and a bore extending from the first end to the second end of the gun barrel housing. Thus, the gun barrel housing defines a tubular body.
The perforating gun system also comprises a rail. The rail defines an elongated frame having a plurality of receptacles. Each receptacle is configured to receive a charge (such as a shaped charge). Each of the shaped charges may be received within a respective receptacle from either side of the frame. In this way, the charges may face opposite directions relative to each other within the wellbore, or the charges may all face in the same direction.
In one aspect, the rail comprises one to five receptacles, meaning one to five charges are received. Preferably, the rail is fabricated from aluminum, an aluminum alloy, or a rigid polymeric material. In one aspect, two rails may be connected end-to-end, effectively forming a single, longer rail with additional receptacles.
A first flange resides at a first end of the rail. Similarly, a second flange resides at a second end of the rail. Each flange includes a plurality of through-openings spaced equi-radially around a perimeter.
The perforating gun system also includes a pair of tandem subs. A first tandem sub is threadedly connected to the first end of the gun barrel housing, while a second tandem sub is threadedly connected to the second end of the gun barrel housing. Each of the first and second tandem subs comprises a first end, a second end opposite the first end, and a bore extending from the first end to the second end.
Preferably, each of the first tandem sub and the second tandem sub comprises male threaded ends. At the same time, the first and second opposing ends of the gun barrel housing each comprises female threads, forming a female-by-female tubular body. In one aspect, each tandem sub houses an addressable switch.
Additionally, the perforating gun system includes a pair of ballasts. These represent a first ballast and a second ballast. Each of the first and second ballasts comprises a weighted body. The first ballast comprises a proximal end connected to the first flange, and a distal end bearingly abutting the first tandem sub. At the same time, the second ballast comprises a proximal end connected to the second flange, and a distal end bearingly abutting the second tandem sub. The weighted bodies reside between the proximal and distal ends of each of the ballasts.
The perforating gun system takes advantage of a pair of bearing connections. In this respect, the system offers a first bearing member supported by the first ballast at the distal end of the first ballast. The system then offers a second bearing member supported by the second ballast at its respective distal end. The first bearing member interfaces with and rotates within the bore of the first tandem sub, while the second bearing member interfaces with and rotates within the bore of the second tandem sub. The result of these interfaces is that the perforating gun system allows for relative rotation between the ballasts and the first and second tandem subs. This, in turn, allows for relative rotation of the rail and supported shaped charges within the gun barrel housing.
The shaped charges may be placed within respective receptacles along the frame to fire at orientations of any of 0 degrees, 90 degrees, 180 degrees, or 270 degrees within the horizontal portion of the wellbore, depending on the direction in which the charges are inserted into the respective receptacles, and depending on the angle at which the ballasts are secured to the flanges of the rail. Intermediate angles (such as 45 degrees, 135 degrees, 225 degrees, and 315 degrees) may be selected at the operator's preference.
In one aspect, a first electrically conductive contact pin resides within the bore of the first tandem sub. Similarly, a second electrically conductive contact pin resides within the bore of the second tandem sub. A detonator resides within the gun barrel housing adjacent the rail and is in electrical communication with the contact pins.
A method of orienting shots in a perforating gun assembly is also provided herein. In one aspect, the method first comprises providing a perforating gun assembly. The perforating gun assembly may be arranged in accordance with any of the embodiments described above. In this respect, the perforating gun assembly includes a gun barrel housing and a pair of tandem subs. Specifically, a tandem sub is placed at each of an opposing ends of the gun barrel housing.
The method also includes providing a rail. The rail defines an elongated frame having a series of receptacles along its length. The receptacles are configured to receive respective charges. Preferably, the receptacles each have a circular profile and are equi-distantly spaced along the frame.
The method further comprises placing a charge within each of the respective receptacles along the frame. Preferably, the rail includes at least three receptacles. Beneficially, the charges may be received within a respective receptacle from either side of the frame.
The method additionally comprises threadedly connecting the first tandem sub to the first end of the gun barrel housing. The method then includes threadedly connecting the second tandem sub to the second end of the gun barrel housing.
The perforating gun system includes a pair of ballasts. These represent a first ballast and a second ballast. Each of the first and second ballasts comprises a weighted body. The first ballast comprises a distal end abutting the first tandem sub. At the same time, the second ballast comprises a distal end abutting the second tandem sub.
The method also comprises providing a first bearing connection between the first ballast and the first tandem sub. Additionally, the method comprises providing a second bearing connection between the second ballast and the second tandem sub. In this way, the first ballast, the second ballast, and the connected rail may rotate together relative to the first and second tandem subs and the connected gun barrel housing.
In one aspect, each of the first and second tandem subs comprises a first end and a second end opposite the first end. Each of the first and second tandem subs further comprises a bore extending between the first end and the second end of the respective tandem sub. The first bearing member interfaces with and rotates within the bore of the first tandem sub, while the second bearing member interfaces with and rotates within the bore of the second tandem sub. This allows for the relative rotation between the rail and the first and second tandem subs.
In one embodiment, the method also includes placing each of the shaped charges into respective charge jackets. Each charge jacket is fabricated from a compliant material, allowing the charges to be removably snapped into place. The rail further comprises slots associated with each of the receptacles. Each of the charge jackets comprises side rails configured to be received within the slots of a respective receptacle along the frame. In this way, the shaped charges are held securely in position along the frame.
The method may also include selecting a direction for each of the shaped charges within its respective receptacle along the frame. The method then includes connecting the proximal end of the first ballast to the first end of the rail, and connecting the proximal end of the second ballast to the second end of the rail.
In one embodiment, the rail comprises a first end defining a first flange, and a second end defining a second flange. The first flange comprises at least four equi-radially spaced through-openings. Similarly, the second flange also comprises at least four equi-radially spaced through-openings. The proximal end of the first ballast comprises a pair of through-openings that may be aligned with a selected pair of the at least four equi-radially spaced through-openings of the first flange. At the same time, the proximal end of the second ballast comprises a pair of through-openings that may be aligned with a selected pair of the at least four equi-radially spaced through-openings of the second flange. In this arrangement, connecting the proximal end of the first ballast to the first end of the rail, and connecting the proximal end of the second ballast to the second end of the rail, comprises:
In one aspect, the method comprises determining which of the through-openings of the first and second flanges that the connectors are to be placed. This determines the relative angle between the weighted bodies of the ballasts and the rail and supported charges. In this way, when the first and second ballasts and the connected rail rotate within a horizontal portion of the wellbore, the charges can be fired downhole at a desired (or pre-selected) orientation.
In one aspect, the charges may be placed within respective receptacles along the frame to fire at orientations of any of 0 degrees, 90 degrees, 180 degrees, or 270 degrees within the horizontal portion of the wellbore, depending on the direction in which the charges are inserted into the respective receptacles and the angle at which the ballasts are secured to the rail. In another aspect, the charges may be placed within respective receptacles along the frame to fire at intermediate angles, such as 45 degrees, 135 degrees, 225 degrees, and 315 degrees.
In one aspect, a first electrically conductive contact pin resides within the bore of the first tandem sub. Similarly, a second electrically conductive contact pin resides within the bore of the second tandem sub. A detonator resides within the gun barrel housing adjacent the rail and is in electrical communication with the first and/or second contact pins.
The method may also include the steps of:
A bearing member assembly is also provided herein. The bearing member assembly is intended to be used in a wellbore completion operation such a casing perforation operation.
In one embodiment, the bearing member assembly first comprises a tubular sub. Preferably, the tubular sub is a tandem sub connected to a gun barrel housing. The tubular sub has a first end and a second end opposite the first end. Connection threads are placed at each of the first and second ends.
An internal bore resides within the tubular sub. The internal bore extends from the first end to the second end. A first profiled shoulder resides along the internal bore at the first end. The first profiled shoulder is positioned within the tubular body around a central axis of the internal bore. The first profiled shoulder forms a first race dimensioned and configured to receive, i.e., engage, rolling elements of a bearing.
Preferably, a second profiled shoulder resides along the internal bore at the second end. The second profiled shoulder is also positioned within the tubular body around a central axis of the internal bore. The second profiled shoulder forms a second race dimensioned and configured to receive or to engage rolling elements of a bearing member.
In each instance, the profiled shoulder preferably represents a tapered profile. The tapered shoulder defines an angle relative to the central axis of the internal bore.
The bearing member assembly also comprises a bearing member. The bearing member includes a tubular support body. The tubular support body has an inner diameter forming a bore, and an outer diameter forming a race. A plurality of roller bearings (or bearing elements) are disposed along the race. The roller bearings reside at an angle that corresponds with the angle of the tapered shoulder of the tubular sub, or are otherwise configured to engage the profiled shoulder.
In one aspect, a housing is provided to secure the plurality of roller bearings against the race. In this way, the housing serves as a cage. The housing defines a frusto-conical profile that corresponds with the angle of the tapered shoulder. The housing comprises a plurality of equi-distantly spaced windows, with each window receiving a respective roller bearing.
In one embodiment, the bearing member assembly also includes a connector housing. The connector housing has a first end, a second end opposite the first end. The connector housing also has a bore residing within the connector housing. The connector housing is fabricated from a non-conductive material. Of interest, the first end of the connector housing extends into the internal bore of the tubular sub. In this embodiment, the bearing member resides between the tapered shoulder of the internal bore of the tubular sub and the connector housing.
In one aspect, a conductive pin resides within the internal bore of the tubular sub. The conductive pin is in electrical communication with a signal line, and is configured to receive a detonation signal from the surface that is sent through the signal line.
A novel tandem sub is also provided herein. The tandem sub is configured to be threadedly connected to a gun barrel housing of a perforating gun assembly. To this end, tubular body includes connection threads. The connection threads are placed at each of the opposing ends.
In one aspect, the tandem sub first comprises a tubular body. The tubular body defines a first end and a second end opposite the first end. An internal bore is formed within the tubular body, extending between the first end and the second end.
A first profiled shoulder resides along the internal bore at the first end. The first profiled shoulder is positioned within the tubular body around a central axis of the internal bore. A second profiled shoulder resides along the internal bore at the second end. The second profiled shoulder is also positioned within the tubular body around a central axis of the internal bore. Beneficially, the first profiled shoulder forms a first race dimensioned and configured to receive (or to engage) roller elements of a first bearing, while the second profiled shoulder forms a second race dimensioned and configured to receive (or to engage) rolling elements of a second bearing.
In one aspect, roller bearings are integral to, or built into, the tandem sub. This represents a plurality of roller bearings disposed along the first race, and a plurality of roller bearings disposed along the second race. A first cage secures the roller bearings against the first race. At the same time, a second cage secures the roller bearings against the second race. Preferably, each of the first cage and the second cage defines a frusto-conical profile.
The roller bearings against the first race are at an angle that corresponds with an angle of the first tapered shoulder. At the same time, the roller bearings against the second race are at an angle that corresponds with the angle of the second tapered shoulder. Preferably, these angles are the same.
The first cage comprises a plurality of windows, with each window receiving a respective bearing member. Similarly, the second cage also comprises a plurality of windows, with each window receiving a respective bearing member. Each of the bearing members extends partially through its respective window.
In one embodiment, the tandem sub further comprises a conductive pin. The conductive pin resides within the internal bore of the tubular sub. In this arrangement, the conductive pin is in electrical communication with a signal line, and is configured to receive a detonation signal from the signal line.
So that the manner in which the present inventions can be better understood, certain illustrations, charts, and/or flow charts are appended hereto. It is to be noted, however, that the drawings illustrate only selected embodiments of the inventions and are therefore not to be considered limiting of scope, for the inventions may admit to other equally effective embodiments and applications.
For purposes of the present application, it will be understood that the term “hydrocarbon” refers to an organic compound that includes primarily, if not exclusively, the elements hydrogen and carbon. Hydrocarbons may also include other elements, such as, but not limited to, halogens, metallic elements, nitrogen, carbon dioxide, and/or sulfuric components such as hydrogen sulfide.
As used herein, the terms “produced fluids,” “reservoir fluids,” and “production fluids” refer to liquids and/or gases removed from a subsurface formation, including, for example, an organic-rich rock formation. Produced fluids may include both hydrocarbon fluids and non-hydrocarbon fluids. Production fluids may include, but are not limited to, oil, natural gas, pyrolyzed shale oil, synthesis gas, a pyrolysis product of coal, nitrogen, carbon dioxide, hydrogen sulfide and brine.
As used herein, the term “fluid” refers to gases, liquids, and combinations of gases and liquids, as well as to combinations of gases and solids, combinations of liquids and solids, and combinations of gases, liquids, and solids as a slurry.
As used herein, the term “surface” refers to a location on the earth's surface. The surface may be a land surface or a water surface.
As used herein, the term “subsurface” refers to geologic strata occurring below the earth's surface.
As used herein, the term “formation” refers to any definable subsurface region regardless of size. The formation may contain one or more hydrocarbon-containing layers, one or more non-hydrocarbon containing layers, an overburden, and/or an underburden of any geologic formation. A formation can refer to a single set of related geologic strata of a specific rock type, or to a set of geologic strata of different rock types that contribute to or are encountered in, for example, without limitation: (i) the creation, generation, and/or entrapment of hydrocarbons or minerals; and (ii) the execution of processes used to extract hydrocarbons or minerals from the subsurface region.
As used herein, the term “wellbore” refers to a hole in the subsurface made by drilling or insertion of a conduit into the subsurface. A wellbore may have a substantially circular cross-section, or other cross-sectional shape. The term “well,” when referring to an opening in the formation, may be used interchangeably with the term “wellbore.” A wellbore may be formed for the purpose of producing hydrocarbon fluids. Alternatively, a wellbore may be completed for the purpose of producing steam in connection with a geothermal project.
The terms “upstream” and “downstream” may be used to indicate the relative position of tools or components within a wellbore.
As used herein, the term “sub” generally refers to a cylindrical body. The sub may have opposing threaded ends and is used to connect tubular bodies in series.
Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment.
The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements.
The following detailed description does not limit the presently disclosed subject matter of this application. Instead, the scope of the invention is defined by the appended claims.
The tandem sub 225 defines a short tubular body having a first end 202 and a second opposing end 204. The tandem sub 225 may be, for example, 1.00 inches to 5.5 inches in length, with the two ends 202, 204 being mirror images of one another. Preferably, the tubular body forming the tandem sub 225 is portless.
The tandem sub 225 includes externally machined threads 206. The threads 206 are male threads dimensioned to mate with female threaded ends of a gun barrel housing. A gun barrel housing is shown at 410 in
Intermediate the length of the tandem sub 225 and between the threads 206 is a shoulder 216. The shoulder 216 serves as a stop member as the tandem sub 225 is screwed into an end 412 or 414 of a gun barrel housing 410. Stated another way, the shoulder 216 serves as a limiter to the tightening of the tandem sub 225 into the gun barrel housing 410. Optionally, grooves 217 are formed equi-radially around the shoulder 216. The grooves 217 removably engage with a tool (not shown) used for applying a rotational force to the tandem sub 225 without harming the rugosity of the shoulder 216. U.S. Pat. No. 11,559,875 describes a socket driver that may be used to connect the tandem sub 225 to the gun barrel housing 212 or 410. The '875 patent is titled “Socket Driver, and Method of Connecting Perforating Guns” and is incorporated herein by reference in its entirety.
The tandem sub 225 includes a central bore 235. As will be described in greater detail below, the bore 235 is dimensioned to receive a bulkhead (shown at 475 of
The contact pin 550 defines an elongated body that is fabricated from brass or a metal alloy comprised at least partially of brass. Thus, the contact pin 550 is electrically conductive.
Circular grooves 212 are formed along the tandem sub 225. Specifically, a pair of circular grooves 212 is provided on opposing sides of the shoulder 216. The grooves 212 are dimensioned and configured to receive respective O-rings (not shown). The O-rings preferably define elastomeric seals that closely fit between an outer diameter of the tandem sub 225 and an inner diameter of the surrounding gun barrel housing 410. The O-rings provide a pressure seal for the gun barrel housing 410 when in the wellbore and prior to charges 540′, 540″ being detonated.
It is noted that the O-rings on the outside diameter (O.D.) of the tandem sub 225 protect an interior of the gun barrel (charges, wires, etc.) from wellbore fluid/pressure. Once the charges are detonated, the interior of the gun barrel floods. The bulkhead 475 and O-rings on the bulkhead 475 protect the upstream gun from flooding when the gun below is flooded from firing.
The gun barrel housing 410 is dimensioned to house components of any known perforating gun. Such components include a detonator and a detonator cord (shown in
It is noted that in
It is believed that the banana terminal 556 arrangement provides better electrical connectivity than the so-called “pin-on-seat” arrangement presently used in many perforating gun systems. The pin-on-seat arrangement relies on a spring-loaded connection that may not always function properly. In the current electrical system, a small, brass female banana plug 558 resides within a connector housing 580. A wire 585 is then crimped or soldered to the banana plug terminal 558.
The contact pin 550 resides within the bulkhead 475. The contact pin 550 includes an enlarged outer diameter portion 555. The enlarged outer diameter portion 555 is arranged with a series of grooves machined into its profile. The grooves (not numbered) cooperate with mating grooves (also not numbered) along an inner diameter of the bulkhead 475. Such an arrangement is described in greater detail in co-owned U.S. Pat. No. 10,914,145 entitled “Bulkhead Assembly for a Tandem Sub, and an Improved Tandem Sub,” which is incorporated herein in its entirety by reference.
Skipping over to
The bulkhead 475 includes a portion 478 having an enlarged inner diameter. This portion 478 accommodates the corresponding enlarged outer diameter portion 555 of the contact pin 550. O-rings 476 are shown along the outer diameter of the enlarged inner diameter portion 478. The O-rings 476 and the enlarged inner diameter portion 478 limit the transmission of fluid and pressure when a downstream perforating gun is detonated.
Returning to
Below the threaded castle nut 275 is a connector housing 580. The connector housing 580 secures a wire 585 extending from the female banana plug terminal 558 and into the gun barrel housing 410. The wire 585 serves as a signal transmission wire, transmitting detonation signals to perforating gun assemblies 400 downhole, from gun-to-gun. Those of ordinary skill in the art will understand that addressable switches 610 residing along the gun barrel housings 410 will watch for a detonation signal addressed to a particular perforating gun assembly 400, causing a detonation signal to be sent into a detonator wire. Thus, the wire 585 from the banana plug terminal 558 extends to the addressable switch 610.
It is noted that wire 585 connects to the addressable switch 610. The addressable switch 610, in turn, connects to a detonator 560 as well as a wire on the female banana plug at an opposing end of the rail/ballast assembly.
In
It is observed that in
In the typical carrier tube arrangement, charges are spaced apart radially and longitudinally along a tubular body. This allows shots to be fired in all radial directions through the production casing 150. However, in the arrangement of
As noted above, it is also desirable to be able to control the orientation at which the shots are fired from the perforating gun assembly 400. To enable the operator to direct the orientation of the shots fired from the charges 540′, 540″, a novel rail system is provided herein. The rail system is shown at 600 and described in connection with
The rail 630 has a first end 632 and a second end 634 opposite the first end 632. Each end 632, 634 represents a circular member, or flange, having a plurality of equi-radially positioned through-openings 612. Preferably, each end 632, 634 comprises at least four, and more preferably eight, through-openings 612.
The through-openings 612 are dimensioned and configured to receive a bolt or screw or other securing member (shown at 629 in
It is understood that the first 632 and second 634 flanges may be located on the distal ends of the two ballasts 620. In this case, the through-openings 622 would be positioned on opposing ends of the rail 630. Thus, the use of flanges 632, 634 for connecting the rail 630 to the ballasts 620 is not limited to the location of the flanges 632, 634. In lieu of flanges 632, 634 and through-openings 622, a clocking mechanism may also be used to adjust the relative rotational positions of the ballasts 620 and the intermediate rail 630.
Each of the ends 632, 634 of the rail 630 comprises a central opening 615. The central openings 615 are dimensioned to receive the detonator cord 545. This allows the detonator cord 545 to pass from the detonator 560, through the central opening 615, into the rail 630, and on to the respective charges 540′, 540″.
The rail 630 further comprises a series of receptacles 635. The receptacles 635 are preferably equi-distantly spaced along a length of the rail 630. The receptacles 635 are uniquely configured to receive respective charge jackets 670. In one aspect, each receptacle 635 has radial edges 631 to accommodate the typically-circular shaped charges 540.
The charge jacket 670 comprises a series of side rails 672. The side rails 672 are placed along opposing sides of the charge jacket 670. The side rails 672 help to support the shaped charges 540′ or 540″. The side rails 672 are also arranged to slidingly engage into cooperating grooves 632 adjacent each receptacle 635 in the rail 630. Thus, the side rails 672 play a role in holding the charges 540′, 540″ in place along the rail 630.
Returning to
As noted above, in
Beneficially, the charge jacket 670 is fabricated from a compliant (or clastic) material, allowing it to be deformed as it is inserted into respective cooperating grooves 632 along the rail 630, and then return to its original shape to remain within the receptacle 635 of the rail 630. Similarly, the charge jacket 670 may be stretched to capture the shaped charge 540, and then rebound to its original shape to hold the charge 540 securely in place.
As noted,
The second end 623 of the weighted body 624 comprises a pair of wings 626. Each wing 626 contains the through-opening 622 referenced above. When the through-openings 622 are aligned with through-openings 612 of the rail 630, a threaded connector 629 is placed through the aligned through-openings 622, 612. The threaded connectors 629 hold the ballast 620 in place relative to the rail 630 and supported charges 540′, 540″.
In an alternative arrangement, a pair of press-fit pins (not shown) are run into the flanges 632, 634 of the rail 630 to secure wings 626 to the opposing flanges 632, 634.
Intermediate the first 621 and the second end 623 of the ballast 620 is a channel 628. Consistent with the semi-circular profile of the ballast 620, the channel 628 is open. The channel 628 is dimensioned to receive a signal transmission wire, such as wire 585 of
In a preferred embodiment, eight through-openings 622, 612 are provided on the end flanges 632, 634 to allow the operator to select a desired orientation of the charges 540′, 540″. A head 1129 serves as a stop member for the connector 629 that prevents the connector 629 from moving completely through the through-openings 622, 612 during assembly. Accordingly, the head 1129 permits the connector 629 to thread into the through-openings 622, 612, secure the ballast members 620 to the rail 630, and prevent over-insertion of the connector 629 during assembly.
The bearing member 660 includes a plurality of individual roller bearings 662. The roller bearings 662 are secured within a housing 664, forming a race for the plurality of individual roller bearings 662. The bearings 662 interface with the second conical opening 270″ of the tandem sub 225, meaning that the roller bearings 662 permit the bearing member 660 to rotate within the second conical opening 270″. In this way, the bearing member 660 provides relative rotational movement between the tandem sub 225 and the ballast 620 (and its connected rail 630 and supported shaped charges 540′, 540″) within the gun barrel housing 410.
Stated another way, each bearing member 660 is designed to engage with a tandem sub 225, wherein the tandem sub 225 comprises a first end 202, a second end 204 opposite the first end 202, connection threads 206 placed at each of the first 202 and second 204 ends, an internal bore 235 within the tandem sub 225 extending from the first end 202 to the second end 202. As shown in
Each bearing member 660 comprises a first end, or shoulder 661, defining a first outer diameter. In addition, each bearing member 660 comprises a second end, or shoulder 663, defining a second outer diameter. The second outer diameter is smaller than the first outer diameter creating the frusto-conical profile. The angle of the frusto-conical profile will match the angle of the tapered shoulder 270′ or 270″.
A tubular support body 668 extends between the first shoulder 661 and the second shoulder 663. The support body 668 is dimensioned to receive the tubular support member 625 of the ballast 620 while supporting the bearing member 660.
The plurality of roller bearings 662 is disposed around the support body 664 intermediate the first shoulder 661 and the second shoulder 663. The plurality of roller bearings 662 is configured to bearingly engage the tapered shoulder 270′ along the inner bore 235 of the tandem sub 225. The roller bearings 662 are contained within the housing 664. At the same time, the housing 664 provides windows 667 for receiving respective roller bearings 662.
The position of the bearing member 660 is shown in
Of interest, the bearings 662 interface with only the inside diameter (I.D.) of the tandem subs 225. The bearings 662 do not interface with the I.D. of the surrounding gun barrel housing 410. This allows for the use of smaller bearings 662, which in turn allows for reduced cost and lower friction.
The frusto-conical, or tapered, roller bearings 662 have a high side load rating and increased durability. The tapered arrangement for the roller bearings 662 also provides an improved electrical/ground connection with a large surface area of contact to improve electrical communication. Those of ordinary skill in the art may understand that the tandem subs 225 are cleaner and offer more reliable ground surfaces than the ID's of traditional gun barrels.
In one embodiment, roller bearings are placed within a cage that is integral to the tapered surfaces 270′, 270″ along the inner bore 235 of the tandem sub 225. In this instance, the race may be an inner race that forms a portion of the inner bore 235, while the housing 664, or cage, is built onto the inner bore 235. A space is preserved between the inner race and the cage which houses the roller bearings. Each ballast 620 employs a corresponding angled, tapered surface at its first end 621. For example, the tubular support member 625 could be modified to include a tapered, or frusto-conical, surface.
In one aspect, the tapered shoulder 270′ or 270″ represents a tubular adapter, e.g., one to three inches, that is not machined directly into the sub 225, but instead simply abuts or attaches to an end of the tandem sub 225 to create the tapered surface at this location. In this instance, the tubular adapter has an outer diameter that is the same as the outer diameter of the tandem sub 225, but employs the tapered shoulder 270′ or 270″ along its inner bore. The bearing member 660 engages the tapered shoulder of an end cap. For purposes of the claims herein, the end cap essentially becomes a part of the tandem sub 225 once it is screwed on.
It is observed that in
In the arrangement of
In operation, the operator will send an electrical signal from the surface 105, down the electric wireline 240, through the body of the contact pin 550, through the female banana plug 558, to the addressable switch 610, into one of the detonator wires (such as 565P), into the detonator 560 inside of the gun barrel housing 410, and then return to ground through another one of the detonator wires (such as 565N). The detonator 560 is packed with an explosive such as RDX. When current is run through the detonator 560, a small explosion is set off by the electrically heated, internal resistor. This small explosion then sets off the detonator cord 545 along the selected gun barrel housing 410.
Of interest, the second detonator wire is connected to the ballast 620, which is fabricated from a conductive material. The ballast 620, in turn is grounded to the bearing assembly 660 and the tandem sub 225. The bearing member 660 is in electrical communication with the tandem sub 225 and then the gun body 410 through the bearing members 662. In this way, the bearing member 660 plays a role in grounding the perforating gun assembly 400.
In practice, a gun barrel housing 410 may have a tandem sub 225, a bearing member 660, a ballast 620, and a rail 630 (or explosive charge holder) at its first 412 end and, optionally, also at its second 414 end. In this instance, a grounding wire (such as wire 565N) is in electrical communication with the gun barrel housing 410 through the bearing members 660 at both ends 412, 414. The benefit is that each end (412 may be the upstream end and 414 may be the downstream end) is part of the same ground circuit. In the unlikely event that one ground fails (such as through dirt on the roller bearings 662 of one bearing member 660 or because a ground wire 565N becomes disengaged), the perforating gun assembly 400 remains grounded through the other bearing member 660. In other words, the ground path is redundantly designed.
The bearing connection (including bearing members 662) provided between the tandem sub 225 and the ballast 620 also provides the operator with at least some measure of control concerning the orientation (or altitude) of charges 540′, 540″ fired into the surrounding formation 115. In this respect, once the perforating gun assembly 400 (that is, the tandem subs 225, the gun barrel housing 410, and the rail system 600 within the gun barrel housing 410) enters the horizontal leg 156 of the wellbore 100, the weighted bodies 624 of the ballasts 620 will roll downward. Because the ballasts 620 are secured to the ends 632, 634 of the rail 630, the rail 630 and its supported charges 540″, 540″ will rotate with the ballasts 620. The rail 630 is symmetrically balanced to be “neutral,” allowing the conductive ballasts 620 to fully dictate the direction the charges 540′, 540″ will face.
Beneficially, no charge carrier tubes are required for placement within the gun barrel housing 410. In this respect, the rail system 600 supports the charges 540′, 540″ along the gun barrel housing 410 rather than the charge carrier tube. In addition, no metal end plates are required at the ends 202, 204 of the tandem subs 225. Instead, the ballasts 620 and rail 630 provide structural support for the detonator 560 and associated charges 540′, 540″.
Based on the tandem subs 225, the eccentric ballasts 620, and the unique bearing connection between the tandem subs 225 and the ballasts 620 within the gun barrel housing 410, a method of orienting shots during a formation fracturing operation is provided herein.
In one embodiment, the method 1400 first comprises providing a gun barrel housing. This is shown in Box 1410 of
The method 1400 also includes providing a rail. This is seen in Box 1415. The rail is configured to support charges (such as shaped charges) along a frame. Specifically, receptacles are provided along the frame in a preferably equi-distantly spaced array in order to receive the shaped charges. The rail may be in accordance with rail 630 shown in
The method 1400 additionally comprises connecting ballasts to ends of the rail. This is offered in Box 1420. The ballasts are connected using threaded cutting screws that are run into aligned through-openings. In an alternate embodiment, the ballasts may be connected via screws (such as connector 629 of
In operation, the ballasts are connected to opposing ends of the rail. The ballasts are connected such that when the gun barrel housing is pumped into a horizontal leg of a wellbore, the ballasts will be gravitionally rotated into a downward position. This downward rotation of the ballasts will turn the receptacles along the rail within the wellbore at desired orientations.
The method 1400 also includes the optional step of providing charge jackets for the shaped charges. This is provided in Box 1425. Each charge jacket is dimensioned to receive and hold any “off-the-shelf” shaped charge. The charge jackets may be in accordance with charge jacket 670 of
The method 1400 also comprises the optional step of determining a location of adjacent wellbores in a hydrocarbon producing field. This is shown at Box 1430. Those of ordinary skill in the art will understand that the hydrocarbon field may, and likely will, comprise numerous wells. In connection with so-called in-fill drilling, new wells are drilled in relative proximity to existing wells. The new well is sometimes referred to as a “child wellbore” or an “offset well,” while an existing adjacent well may be referred to as a “parent wellbore.”
In this instance, the operator may desire that shots be fired not only horizontally, but also in one direction only, that is, away from a parent wellbore. This assists the service company in generating and propagating fractures in a particular part of the formation to avoid frac hits. Those of ordinary skill in the art will appreciate that frac hits are generally a by-product of in-fill drilling. Frac hits are also, of course, a by-product of tight well spacing, that is, wells spaced in close proximity to one another in the same field. Ultimately, however, frac hits are the result of the operator being unable to control or “direct” the propagation of fractures within the pay-zone. By firing shots away from a direction of a parent well, the likelihood of a frac hit occurring is reduced.
The method 1400 further includes the optional step of placing the shaped charges into the charge jackets. This is provided at Box 1435. Thereafter, the charge jackets are inserted into receptacles (such as receptacles 635) provided along the rail. This is shown at Box 1440.
It is noted that in lieu of charge jackets, the operator may simply clip the shaped charges onto the receptacles. What is important is that the charge jackets are inserted in select directions. Depending on the placement of the charges along the rail and the angle at which the ballasts are secured to the rail, charges may be shot at a variety of orientations. Examples may be 90-90-90, 270-270-90, 0-90-180, etc.
Beneficially, this allows the operator to orient charges away from a known pressure sink in the formation, such as a pressure sink caused by a parent wellbore in the same field. To facilitate this, the charge jackets are run into the rail from only one direction, e.g., 0-0-0, 90-90-90, 180-180-180, or 270-270-270. This minimizes the chances of a frac hit occurring during formation fracturing.
Optionally, charge jackets may be placed along the rail in a way that charges will fire vertically, e.g., 0-180-0. This too may minimize the chances of a frac hit occurring during formation fracturing. Of course, the rail may be connected to the ballasts at any angle and the charges may be inserted into the rail receptacles from either direction, providing a high degree of pre-selection for the orientation of the charges.
The method 1400 additionally includes connecting the charges to a detonator cord. This is offered in Box 1445. The operator then positions the rail and the supported charges within the gun barrel housing. This is seen in Box 1450 of
As discussed above, the novel perforating gun assembly described herein offers a bearing connection within the gun barrel housing. Thus, in Box 1455 the method includes the step of providing a bearing member at an end of each ballast. Each of the bearing members may be in accordance with the bearing member 660 of
The method 1400 next includes threadedly connecting each end of the gun barrel housing to a tandem sub. This is seen in Box 1460. Upon connection, the bearing members engage an inner diameter of the respective tandem subs. Together, the tandem subs, the gun barrel housing, the roller bearings (or bearing members), the ballasts, the rail, and the charges form a novel perforating gun assembly.
As an alternative, at least one bearing member is connected to an end plate, which in turn is connected to a gun barrel housing. The end plate comprises a short tubular body, such as one to three inches, that screws onto or otherwise attaches to the second end of the gun barrel housing. In this case, an opposite end of the end plate may screw into the first end of an adjoining gun barrel housing, or onto a setting tool for a plug, as the case may be.
The method 1400 may also include running the perforating gun assembly into a wellbore. This is provided at Box 1465. This step is typically done by running the perforating gun assembly into the wellbore at the end of an electric wireline (such as wireline 240 of
Once the perforating gun assembly is positioned within the horizontal portion of the wellbore, the ballasts are allowed to rotate into a downward position. This occurs automatically in response to the gravitational force acting on the weighted bodies. This step is shown in Box 1475. This rotation takes place through the bearing members. The result is that the shaped charges are oriented at a desired angle and/or direction within a surrounding formation.
It will be appreciated by the petroleum engineer that the size and orientation of a fracture, and the amount of hydraulic pressure needed to part the rock along a fracture plane, are dictated by the formation's in situ stress field. This stress field can be defined by three principal compressive stresses which are oriented perpendicular to one another. These represent a vertical stress, a minimum horizontal stress, and a maximum horizontal stress. The magnitudes and orientations of these three principal stresses are determined by the geomechanics in the region and by the pore pressure, depth, and rock properties.
According to principles of geomechanics, fracture planes will generally form in a direction that is perpendicular to the plane of least principal stress in a rock matrix. Stated more simply, in most wellbores, the rock matrix will part along vertical lines when the horizontal section of a wellbore resides below 3,000 feet, and sometimes as shallow as 2,000 feet, below the surface. In this instance, hydraulic fractures will tend to propagate from the wellbore's perforations in a vertical, elliptical plane perpendicular to the plane of least principal stress. If the orientation of the least principal stress plane is known, the longitudinal axis of the horizontal leg 156 is ideally oriented parallel to it such that the multiple fracture planes will intersect the wellbore 100 at, or near, orthogonal to the horizontal leg 156 of the wellbore 100.
The method 1400 may finally include sending an actuation signal down the electric line to initiate charges and to create perforations in a direction that is generally opposite from a direction of the parent wellbore, thus avoiding a frac hit in the hydrocarbon producing field while optimizing the creation of a fracture network within the formation. This may be a part of the step of Box 1475.
Further, variations of the novel tandem sub for a perforating gun assembly and of methods for using the tool within a wellbore may fall within the spirit of the claims, below. It will be appreciated that the disclosures provided herein are susceptible to other modifications, variations and changes without departing from the spirit thereof.
This application is filed as a continuation-in-part of U.S. Ser. No. 18/586,504. That application was filed on Feb. 25, 2024 and was entitled “Roller Bearing Assembly, and Method of Grounding a Perforating Gun Assembly.” This '504 application, in turn, was filed as a continuation-in-part of U.S. Ser. No. 18/435,553. That application was filed on Feb. 7, 2024 and was entitled “Orienting Perforating Gun System, and Method of Orienting Shots in a Perforating Gun Assembly.” The parent application claimed the benefit of U.S. Ser. No. 63/497,305. That application was filed on Apr. 20, 2023 and was entitled “Orienting Perforating Gun System, and Method of Orienting Shots in a Perforating Gun Assembly.” The parent application also claimed the benefit of U.S. Ser. No. 63/511,903. That application was filed on Jul. 5, 2023 and was entitled “Orienting Perforating Gun System, and Method of Orienting Shots in a Perforating Gun Assembly.” The '504 application was filed as a continuation-in-part of U.S. Ser. No. 29/920,858 filed Dec. 13, 2023. That application is titled “Tandem Sub for a Roller Bearing.” The '504 application was also filed as a continuation-in-part of U.S. Ser. No. 29/920,815 filed Dec. 13, 2023. That application is titled “Roller Bearing for a Tandem Sub.” Each of these filings is incorporated herein in its entirety by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63497305 | Apr 2023 | US | |
| 63511903 | Jul 2023 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18586504 | Feb 2024 | US |
| Child | 18642127 | US | |
| Parent | 18435553 | Feb 2024 | US |
| Child | 18586504 | US | |
| Parent | 29920858 | Dec 2023 | US |
| Child | 18435553 | US | |
| Parent | 29920815 | Dec 2023 | US |
| Child | 29920858 | US |
