Patent ID: 12196046

DEFINITIONS

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 water.

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 shapes. The term “well,” when referring to an opening in the formation, may be used interchangeably with the term “wellbore.”

As used herein, the term “sub” generally refers to a tubular 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.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

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 invention; instead, the scope of the invention is defined by the appended claims.

The present invention relates to a roller sub useful for moving a downhole tool through a horizontal (or otherwise deviated) portion of a wellbore. The roller sub generally comprises two components: (1) a tubular body (seen at300inFIGS.3A and3B), and (2) a roller body (seen at500inFIG.5A). Together, the tubular body300and the roller body form a roller sub (shown at600inFIG.6B).

FIG.3Ais a perspective view of the tubular body300referenced above. The tubular body300forms a portion of the roller sub600. The tubular body300serves two purposes. First, the tubular body300provides support for holding the roller body500along a tool string. Second, the tubular body300offers threaded ends312,314used to connect two perforating guns end-to-end, forming a tool string.

FIG.3Bis a cut-away view of the tubular body300ofFIG.3A. Here, an inner bore315of the tubular body300is shown. The tubular body300will be discussed with reference toFIGS.3A and3Btogether.

The tubular body300defines a generally tubular body having a first end312and an opposing second end314. Each end312,314represents a threaded connector. Threads are shown inFIG.3Bat311. Preferably, each end312,314defines female threads311for receiving male threads from an adjoining wellbore tool or connector sub (such as tandem sub225ofFIG.2). In addition, each of the first and second ends312,314has a first outer diameter D1.

The first312and second314ends, with their threads311, form couplings317. In one aspect, each coupling317extends inward from the threads about one to four inches. Flat surfaces (or “flats”)313may be placed around the couplings317for use in connecting and subsequently tightening (i.e., “torquing”) the sub300onto an adjoining tandem sub (as shown at225ofFIG.4).

The tubular body300also comprises an elongated shaft316. The elongated shaft316extends between the first312and the second ends314forming a part of the tubular body. Of interest, the shaft316has a second outer diameter that is smaller than the first outer diameter. The outer diameter (or O.D.) minimum is limited by the bending stress applied when picking up the tool string400from horizontal to vertical.

The shaft316and opposing couplings317may be fabricated from a high strength steel. Alternatively, the shaft316and couplings317may comprise titanium, beryllium, or copper. Combinations of these materials, forming an alloy, may also be used. Preferably, the shaft316, or more specifically the material comprising the shaft316, has a modulus of elasticity that allows the shaft316to deform as it is pumped across or pulled out of the heel153of a wellbore100, and allowing the shaft316to return to its original shape.

The tubular body300optionally comprises a pair of transition sections318. Each transition section318resides between the shaft316and the opposing first312or second end314. Each transition section318is about one to four inches in length. Preferably, the shaft316represents 40% to 70% inclusive of the end-to-end length of the tubular body300. The remaining length is the couplings317, that is, the transition sections318and the ends312,314.

The tubular body300is configured to slidably receive a data cable or an electrical wire340for the transmission of signals, data or power. In this regard, the bore315of the tubular body300has a bore315configured to receive the cable or wires340. A smaller inside diameter for bore315is preferred to closely hold the cable or wires340.

The tubular body300is designed to reside along an otherwise rigid string of tools, such as the gun barrel assembly200ofFIG.2. In a preferred embodiment, the flexible tubular body300is threadedly placed between two perforating guns, such as perforating guns210ofFIG.2. Traditional gun barrels (the rigid housings212of the perforating guns210) are female-by-female, with the connecting tandem subs225being male-by-male, meaning that each end of a tandem sub225has male threads. With this in mind, the tubular sub300may be used as an in-line replacement for any typical gun barrel by using the same female-by-female threaded ends.

Of course, the same ends312,314of the tubular sub300may be made with any combination of threads, such as male-by-female. Instead of replacing just a gun barrel, the operator may instead replace both a gun barrel and a sub together and then use a tubular sub300having male-by-female threaded ends. However, with the female-by-female design, no additional insulators, conductors, contact pins, or springs are required, as the design may utilize the existing gun wire and bulkheads to pass electrical continuity through the bore315downhole as the replaced gun barrel would.

FIG.4is an exploded, side view of the tubular body300ofFIGS.3A and3B. Here, the tubular body300is shown between opposing tandem subs225of a perforating gun assembly400. The perforating gun assembly400may be in accordance with the perforating gun assembly200as shown inFIG.2. In this instance, the perforating gun assembly400comprises tandem subs225, perforating guns210, and the tubular body300. Of course, the perforating gun assembly400may comprise additional elements when used downhole, such as additional tandem subs225and perforating guns210to form a complete tool string.

In this view, the tandem subs225are shown in greater illustrative detail and are exploded away from the tubular body300, revealing male threaded ends227. The male threaded ends227thread directly into respective female threaded ends312,314(or couplings317) of the tubular body300.

In addition to the tandem subs225, perforating guns210are shown in an exploded view away from opposing ends of the tubular body300. In this arrangement, the tubular body300is connected to the perforating guns210by means of the tandem subs225.

Each tandem sub225has a male threaded end227on each end of the tandem sub225. One male end227of a tandem sub225connects to a female end, e.g., end312, of the tubular body300, while the other male end227of the tandem sub225connects to a female end217of the perforating gun210. In essence, the tubular body300serves as a flexible, “blank” perforating gun in a perforating gun assembly.

The tubular body300preferably has a length of between five and twelve inches. In one aspect, the tubular body300has an overall length that matches or approximates the length of the gun barrels210used in the perforating gun assembly (i.e., tool string)200. For example, if there are 16-inch long gun barrels being used, the tubular body300will also be 16 inches from end312to end314. Of course, the length of the tubular body300may be longer or shorter than the gun barrels210. However, the longer the length of the tubular body300, the more flex/deviation the body300will offer, allowing the operator to navigate through more highly deviated wellbores100.

As noted above, the inner bore315of the tubular body300serves as an internal chamber that permits wires and/or data cables340to travel down the tool string200en route to a next perforating gun210downhole. The wires or data cables340extend through the perforating gun assembly400, transmitting detonation signals one perforating gun210at a time. When a detonation signal is received from the wireline240, electronics inside the tandem sub225initiate the detonation of the immediately-upstream perforating gun210.

In one unique embodiment, certain electronics are stored in the tandem sub225rather than in the perforating gun housing (i.e., gun barrel)212. The adjoining tandem sub225holds a seal mechanism (not shown) that is designed to pressure seal the downstream end of the bore of the sub225. In this way, detonation of the shaped charges of a downstream perforating gun210does not damage the electronics inside the tandem sub225. An illustrative arrangement for a seal mechanism is presented in co-owned U.S. Pat. No. 11,402,190. This patent is entitled “Detonation System Having Sealed Explosive Initiation Assembly” and is incorporated herein in its entirety by reference.

FIG.5Ais a perspective view of the roller body500of the present invention, in one embodiment. Here, opposing halves510,520of the roller body500have been placed together, forming a cylindrical body.FIG.5Cis a cut-away view of the roller body500ofFIG.5A. The roller body500has been cut through a vertical axis, leaving half of each of the opposing halves510,520. The roller body500will be discussed further with reference toFIGS.5A and5Ctogether.

The opposing halves510,520may be referred to herein as an upper half510and a lower half520. The upper half510is comprised of a series of semi-circular discs512placed side-by-side. Similarly, the lower half520is comprised of a series of semi-circular discs522placed side-by-side. Residing between the semi-circular discs512of the upper half510are bearing members516. Reciprocally, residing between the semi-circular discs522of the lower half520are bearing members526. Together, the bearing members516,526permit relative rotational movement between the elongated shaft316and the surrounding roller body500.

Semi-circular end plates518are placed at opposing ends of the upper half510of the roller body500. Similarly, semi-circular end plates528are placed at opposing ends of the lower half520of the roller body500. Pins519,529extend through longitudinal lengths of the upper half510and the lower half520in order to secure the semi-circular discs512,522together and in place.

It is understood that other equally effective bearing arrangements may be used in place of the small rollers shown as bearing members516,526. For example, one or more of the semi-circular discs512,522could be configured to rotate within the roller body500. In this arrangement, such semi-circular discs would have a smaller I.D. than the other semi-circular discs.

It is necessary to secure the upper half510of the roller body500to the lower half520. To this end, bolts (shown at530in the translucent views ofFIGS.7A and7B) may be placed within openings within the roller body500. Openings514are placed within the upper half510of the roller body500. Likewise, openings524are placed within the lower half520of the roller body500. Openings514and524are aligned in order to receive the bolts530.

FIG.5Bis a perspective view of the roller body500ofFIG.5A. In this arrangement, weights have been placed along threads that are part of a downhole tool (such as tool810ofFIG.8A). The one or more weights are eccentric to, or decentralized from, the downhole tool810. Weights540′ are placed upstream of the roller body500, while weight540″ is placed downstream of the roller body500.

When the downhole tool810resides between two roller bodies500, the downhole tool810will rotate, or swing, into a position where the one or more weights reside at the bottom of the horizontal section156of the wellbore100. Where the downhole tool810is a perforating gun, the one or more weights may be an elongated orienting weight bar. More preferably, the weight bar is a separate body threadedly connected in series with the tool string800.

FIG.6Ais a side, perspective view of a tubular body300′ in an alternate arrangement. The tubular body300′ has a first end312′ and an opposing second end314′.

Here, opposing halves of the roller body500have been removed from opposite sides of the elongated shaft316of the tubular body300′.

FIG.6Bis another side view of the tubular body300′ ofFIG.6A. Here, opposing halves510,520of the roller body500have been connected to each other, surrounding the elongated shaft316. Together, the tubular body300′ and the roller body500form a roller sub600.

FIG.7Ais another perspective view of the roller body500ofFIG.5A. Here, the upper half510of the roller body500is transparent, revealing connective hardware.

FIG.7Bis an end view of the roller body500ofFIG.5A. Both halves510,520of the roller body500are transparent, revealing connective hardware.

FIG.8Ais a perspective view of a tool string800. The tool string800defines a series of downhole tools810. The tools810inFIG.8Aare shown as being generic. However, it is understood that the tools810may be any tool, such as a perforating gun that is run into a horizontal section of a wellbore, such as wellbore100ofFIG.1. In the arrangement ofFIG.8A, four gun strings may be visualized as the downhole tools810.

Along the tool string800are two roller bodies500. The roller subs600are placed in series between the downhole tools810. The roller bodies500are intended to be in accordance with the roller sub500ofFIG.5A. In this respect, the roller bodies500include bearing members516,526that permit the semi-circular discs512,522to rotate about a fixed elongated shaft such as elongated shaft316ofFIG.3A.

It is observed that the downhole tools810have a first outer diameter, shown as D1. The ends312,314of the roller body300create shoulders having the first outer diameter D1. The roller bodies500have a second outer diameter, shown as D2. The second outer diameter D2is greater than the first outer diameter D1. The second outer diameter D2is configured to closely reside within the inner diameter of the horizontal portion156of the production casing150.

FIG.8Bis an enlarged view of a portion of the tool string800ofFIG.8A. One of the roller bodies500is shown with greater clarity. The roller bodies500permit the overall tool string800to twist within the horizontal section156of the production casing150without becoming bound up, or torqued. Stated more simply, the roller bodies500reduce the rotational friction of the tool string800within the horizontal section156. More importantly, the ability of the tool string800to rotate relative to the roller bodies500and the surrounding casing150keeps the working string (such as wireline240) from becoming torqued.

The larger O.D. of the roller body500can be seen relative to the adjacent downhole tools810. This allows the weight of the tool string800to be placed on the roller bodies500when the tool string800is horizontal.

In one aspect, a full tool string800may look like:Orienting Weight Bar→Roller Sub Assembly→Orienting Weight Bar→Roller Sub Assembly→Cable Head→Casing Collar Locator→Perforating Gun1→Roller Sub Assembly→Perforating Guns2and3→Roller Sub Assembly→etc.

Using the tubular body300and the roller body500(together roller sub600), a method of running a tool string into a wellbore is provided. The method first comprises providing a wellbore. The wellbore has a deviated section such as the horizontal leg156of the wellbore100ofFIG.1. The term “providing” may mean that a service company accesses a wellbore that has been drilled by a drilling company and has been at least partially completed by a separate service company.

The method also includes running a tool string into the wellbore. The tool string may comprise:a first downhole tool810;a second downhole tool810; anda roller sub600residing intermediate the first downhole tool and the second downhole tool.

The roller sub has a tubular body comprising an elongated shaft. The elongated shaft has a first end and an opposing second end. Additionally, the elongated shaft defines a bore extending between the first and second ends. The bore is dimensioned to receive an electrical wire or data cable. Preferably, the elongated shaft is fabricated from steel, titanium, beryllium copper, or a metal alloy thereof.

First threads are provided at the first end of the tubular body for engaging the first downhole tool. Similarly, second threads are provided at the opposing second end for engaging the second downhole tool.

A first shoulder resides proximate the first end of the elongated shaft of the tubular body. Additionally, a second shoulder resides proximate the second end of the elongated shaft of the tubular body. Each of the first shoulder and the second shoulder defines a first outer diameter.

The roller sub also includes a roller body. The roller body is releasably clamped onto the elongated shaft of the cylindrical body between the first shoulder and the second shoulder. The roller body has a second outer diameter that is greater than the first outer diameter, and comprises at least two bearing members. The bearing members permit relative rotational movement between the roller body and the tubular body.

The method further comprises passing the tool string through at least a portion of the deviated section.

In a preferred arrangement, the roller body comprises an upper portion and a lower portion. In one aspect, the upper portion is an upper half portion while the lower portion is a lower half portion. Each of the upper portion and the lower portion comprises a series of semi-circular disks placed in series. Additionally, each of the upper portion and the lower portion comprises a series of openings, with the openings in the upper portion being aligned with the openings in the lower portion. Finally, the roller sub further may comprise a plurality of bolts configured to be received within the openings in the upper portion and the lower portion, and to secure the upper portion to the lower portion.

The method then further comprises clamping the upper portion and the lower portion onto and around the elongated shaft between the first shoulder and the second shoulder. In this way, the roller body is releasably clamped onto the elongated shaft between the two shoulders. The tool string is preferably run into the wellbore at the end of an electric wireline. In this instance, passing the tool string through the deviated section comprises pumping the tool string downhole using hydraulic pressure.

In a preferred embodiment, each of the first and second downhole tools is a perforating gun. In this instance, the tool string is a perforating gun assembly. Each of the first and second downhole tools defines a third outer diameter formed by a respective gun barrel housing, wherein the second outer diameter is also larger than the third outer diameter.

Where the tool string is a perforating gun assembly, the first threads constitute female threads configured to be threaded onto an end of a first male-by-male tandem sub. Similarly, the second threads constitute female threads configured to be threaded into an end of a second male-by-male tandem sub.

In one aspect, a second end of the first male-by-male tandem sub is connected to a first perforating gun. The second threads constitute female threads configured to be threaded into a second end of a second male-by-male tandem sub. Additionally, a second end of the second male-by-male tandem sub may be connected to a second perforating gun.

The disclosed embodiments provide methods and systems for preventing electronics located inside a switch sub from being damaged by detonation of an adjacent perforating gun. It should be understood that this description is not intended to limit the invention; on the contrary, the exemplary embodiments are intended to cover alternatives, modifications, and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth to provide a comprehensive understanding of the claimed subject matter. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.

Further, variations of the detonation system and of methods for using the detonation system within a wellbore may fall within the spirit of the claims, below. It will be appreciated that the inventions are susceptible to other modifications, variations, and changes without departing from the spirit thereof.