Offset flange and angled shim flowline fittings

Abstract

Flowline components are assembled into high-pressure fluid transportation systems by a flange union. The flowline component comprises a body defining a substantially cylindrical central conduit. The conduit extends between first and second flat union faces and is adapted to conduct fluids through the body. The union faces are adapted to provide a mating surface for a flange union between the component and another flowline component. Accordingly, the union faces have a plurality of holes adapted to accommodate threaded connectors for forming the flange union. The holes are arranged in a defined array extending angularly around the conduit. Importantly, the array of holes on the first union face and the array of holes on the second union face are offset angularly relative to each other by an angle . It will be appreciated that such components may allow changes in the direction of a flow line.

Claims

1. A flowline component adapted for assembly into a high-pressure fluid transportation system, said flowline component comprising: (a) a body defining a substantially cylindrical central conduit, said conduit extending between first and second union faces and adapted to conduct fluids through said body; (b) said union faces being adapted to provide a mating surface for a flange union between said component and another flowline component; (c) said union faces having a plurality of holes adapted to accommodate threaded connectors for forming said flange union; and (d) said holes being arranged in a defined array extending angularly around said conduit; (e) wherein said array of holes on said first union face and said array of holes on said second union face are offset angularly relative to each other by an angle .

2. The flowline component of claim 1, wherein said arrays of holes comprise 16 holes spaced angularly at 22.5 and said offset angle is 11.25 or 7.5.

3. The flowline component of claim 1, wherein said arrays of holes comprise 12 holes spaced angularly at 30 and said offset angle is 15 or 10.

4. The flowline component of claim 1, wherein said arrays of holes comprise 8 holes spaced angularly at 45 and said offset angle is 22.5 or 15.

5. The flowline component of claim 1, wherein said component is a pipe having flanges and said flanges on said pipe provide said union faces and said holes accommodate the passage of said threaded connectors through said flange.

6. A flow line for a high-pressure fluid transportation system, said flow line comprising the flowline component of claim 5 assembled into said flow line by flange unions.

7. A high-pressure fluid transportation system, said system comprising the flow line of claim 6.

8. The high-pressure fluid transportation system of claim 7, wherein said system is a frac system.

9. The high-pressure fluid transportation system of claim 7, wherein said system is a frac system comprising: (a) a plurality of pumping units each having discharge lines; (b) a well head; and (c) a single said flow line connected to each of said pump discharge lines and to said well head, whereby all fluid discharged from said pumps is conveyed by said single flow line to said well head.

10. The flowline component of claim 1, wherein said component is a block fitting and said holes are bottomed holes accommodating engagement with said threaded connectors.

11. A flow line for a high-pressure fluid transportation system, said flow line comprising the flowline component of claim 1 assembled into said flow line by flange unions.

12. A high-pressure fluid transportation system, said system comprising the flow line of claim 11.

13. The high-pressure fluid transportation system of claim 12, wherein said system is a frac system comprising: (a) a plurality of pumping units each having discharge lines; (b) a well head; and (c) a single said flow line connected to each of said pump discharge lines and to said well head, whereby all fluid discharged from said pumps is conveyed by said single flow line to said well head.

14. The high-pressure fluid transportation system of claim 13, wherein said well head comprises a zipper manifold.

15. The high-pressure fluid transportation system of claim 12, wherein said system is a frac system.

16. A method of assembling a flow line for a high-pressure fluid transportation system, said method comprising assembling the flowline component of claim 1 into said flow line by connecting said flowline component to other flowline components by a flange union.

17. A directional flowline fitting, said fitting being adapted for assembly into a flowline segment providing a single conduit in a fluid transportation system to provide a change of direction in said single-conduit segment; said fitting comprising: (a) a prismatic body having a single conduit therein consisting of first and second intersecting straight line bores, said first bore providing an inlet and said second bore providing an outlet; (b) said bores extending from, respectively, a first union face and a second union face on said body, said union faces being adapted for connection to a flowline component by a flange union; (c) wherein the extended planes of said first and second union faces intersect at an interior angle less than approximately 90.

18. The flowline fitting of claim 17, wherein said angle is approximately 45 or approximately 60.

19. A flowline segment providing a single conduit in a high-pressure fluid transportation system, said single-conduit segment comprising the fitting of claim 17 assembled into said single-conduit segment by flange unions, whereby said single-conduit segment is provided with a change of direction greater than 90.

20. A high-pressure fluid transportation system, said system comprising the single-conduit flowline segment of claim 19.

21. The high-pressure fluid transportation system of claim 20, wherein said system is a frac system comprising: (a) a plurality of pumping units each having discharge lines; (b) a well head; and (c) a single flow line incorporating said single-conduit flowline segment and connected to each of said pump discharge lines and to said well head, whereby all fluid discharged from said pumps is conveyed by said single flow line to said well head and said single-conduit flowline segment provides a change in direction of said flowline.

22. The frac system of claim 21, wherein said single flow line does not comprise a swivel joint.

23. A method of assembling the flow line for a high-pressure fluid transportation system, said method comprising assembling a flowline segment of claim 17 into said flow line.

24. The flowline fitting of claim 17, wherein said body is a truncated solid rectangle.

25. A flowline segment providing a single conduit in a high-pressure fluid transportation system, said single-conduit segment comprising the fitting of claim 24 assembled into said single-conduit segment by flange unions, whereby said single-conduit segment is provided with a change of direction greater than 90.

26. A high-pressure fluid transportation system, said system comprising the single-conduit flowline segment of claim 25.

27. The high-pressure fluid transportation system of claim 26, wherein said system is a frac system.

28. The high-pressure fluid transportation system of claim 26, wherein said system is a frac system comprising: (a) a plurality of pumping units each having discharge lines; (b) a well head; and (c) a single flow line incorporating said single-conduit flowline segment and connected to each of said pump discharge lines and to said well head, whereby all fluid discharged from said pumps is conveyed by said single flow line to said well head and said single-conduit flowline segment provides a change in direction of said single flow line.

29. A flowline segment providing a single conduit in a high-pressure fluid transportation system, said single-conduit segment having a change in direction and comprising: (a) an offset component assembled into said segment by flange unions, said offset component comprising: i) a body defining a substantially cylindrical central conduit, said conduit extending between first and second union faces and adapted to conduct fluids through said body; ii) said union faces having a plurality of holes accommodating threaded connectors for said flange unions; and iii) said holes being arranged in a defined array extending angularly around said conduit; iv) wherein said array of holes on said first union face and said array of holes on said second union face are offset angularly relative to each other by an angle ; and (b) a directional fitting assembled into said segment by flange unions, said directional fitting comprising: i) a prismatic body having a single conduit therein consisting of first and second intersecting straight line bores; and ii) said bores extending perpendicularly from a first union face and a second union face on said body; iii) wherein the extended planes of said first and second union faces intersect at an interior angle less than approximately 90.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 (prior art) is a schematic view of a system for fracturing a well and receiving flow back from the well, which system includes various high-pressure flow lines, such as flow lines 12 and 14.

(2) FIG. 2 is a schematic view of a frac system incorporating a first preferred embodiment 100 of the flow lines of the subject invention, which flow line 100 provides a single high-pressure conduit between pumps 10 and zipper manifold 16.

(3) FIG. 3 is an isometric view of novel flow line 100.

(4) FIG. 4 is an elevational view of flow line 100 shown in FIG. 3,

(5) FIG. 5 is a top plan view of flow line 100 shown in FIGS. 3-4.

(6) FIG. 6 is an isometric view of a first preferred embodiment 120 of a block junction which may be used, for example, in flow line 100, which junction 120 provides an offset cross junction in flow line 100.

(7) FIG. 7 is a cross-sectional view of offset cross junction 120 shown in FIG. 6.

(8) FIG. 8 is a cross-sectional view of a second preferred embodiment 220 of a block junction which may be used, for example, in flow line 100. Junction 220 is substantially identical to offset cross junction 120 shown in FIGS. 6-7 except that it incorporates wear sleeves 222 and 226.

(9) FIG. 9 is a cross-sectional view of a third preferred embodiment 320 of a block junction which may be used, for example, in flow line 100. Junction 320 is substantially identical to offset cross junction 120 shown in FIGS. 6-7 except that it incorporates wear sleeves 322 and 326.

(10) FIG. 10 is an isometric view of a second preferred embodiment 420 of a block junction which may be used, for example, in flow line 100, which junction 420 provides an offset lateral cross junction in flow line 100.

(11) FIG. 11 is a cross-sectional view of offset lateral cross junction 420 shown in FIG. 10.

(12) FIG. 12 is an isometric view of a third preferred embodiment of a block junction 520 which may be used, for example, in flow line 100, which junction 520 provides a right-angle cross junction in flow line 100.

(13) FIG. 13 is a cross-sectional view of right-angle cross junction 520 shown in FIG. 12.

(14) FIG. 14 is an isometric view of a block cross junction 20 used in flow line 100.

(15) FIG. 15 is a cross-sectional view of cross junction 20 shown in FIG. 14.

(16) FIGS. 16-17 are isometric views of a first preferred embodiment 140 of the angled shims of the subject invention which may be used, for example, in flow line 100.

(17) FIG. 18 is a cross-sectional view of novel angled shim 140 shown in FIGS. 16-17.

(18) FIG. 19 is a cross-sectional view of a second preferred embodiment 240 of the angled shims of the subject invention which may be used, for example, in flow line 100. Angled shim 240 is substantially identical to angled shim 140 shown in FIGS. 16-18 except that it incorporates wear sleeves 248.

(19) FIG. 20 is a cross-sectional view of a third preferred embodiment 340 of the angled shims of the subject invention which may be used, for example, in flow line 100. Angled shim 340 is substantially identical to angled shim 140 shown in FIGS. 16-18 except that it incorporates wear sleeves 348.

(20) FIG. 21 is an isometric view of a first preferred embodiment 130 of the offset spools of the subject invention which may be used, for example, in flow line 100.

(21) FIG. 22 is an end plan view of the novel offset spool 130 shown in FIG. 21.

(22) FIG. 23 is a cross-sectional view of offset spool 130 shown in FIGS. 21-22.

(23) FIG. 24 is a cross-sectional view of a second preferred embodiment 230 of the offset spools of the subject invention which may be used, for example, in flow line 100. Offset spools 230 is substantially identical to offset spool 130 shown in FIGS. 21-23 except that it incorporates wear sleeves 238.

(24) FIG. 25 is a cross-sectional view of a third preferred embodiment 330 of the offset spools of the subject invention which may be used, for example, in flow line 100. Offset spools 330 is substantially identical to offset spool 130 shown in FIGS. 21-23 except that it incorporates wear sleeves 338.

(25) FIG. 26 is an isometric view of a first preferred embodiment 160 of the skids of the subject invention showing a flowline subassembly 101 supported thereon.

(26) FIG. 27 is a side elevational view of skid 160 shown in FIG. 26.

(27) FIG. 28 is a top plan view of skid 160 shown in FIGS. 26-27.

(28) In the drawings and description that follows, like parts are identified by the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional design and construction may not be shown in the interest of clarity and conciseness.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(29) The invention, in various aspects and embodiments, is directed generally to fluid transportation systems and flow lines used in those systems, and especially to flow lines and flowline components that are used to convey abrasive, corrosive fluids under high pressure. Various specific embodiments will be described below. For the sake of conciseness, all features of an actual implementation may not be described or illustrated. In developing any actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve a developers' specific goals. Decisions usually will be made consistent within system-related and business-related constraints, and specific goals may vary from one implementation to another. Development efforts might be complex and time consuming and may involve many aspects of design, fabrication, and manufacture. Nevertheless, it should be appreciated that such development projects would be a routine effort for those of ordinary skill having the benefit of this disclosure.

(30) The novel flowlines and flowline components typically will be used to connect process or flow units for temporary fluid transportation systems. They are particularly useful for temporary installations that must be assembled and disassembled on site. Such systems are common in chemical and other industrial plants, on marine dredging vessels, strip mines, and especially in the oil and gas industry. Frac systems, such as those shown in FIG. 1, are a very common application where temporary high-pressure flow lines are routinely used to provide fluid conduits between process or flow units.

(31) The novel flow lines and flowline components are particularly suited for use in frac systems such as the system shown in FIG. 1. For example, a first preferred embodiment 100 of the flow lines of the subject invention is shown schematically in FIG. 2. In many respects the novel frac system shown in FIG. 2 is identical to the frac system of FIG. 1. It will be noted, however, that the frac system of FIG. 1 incorporates a pair of relatively small diameter missiles 13 in frac manifold 9. Missiles 13 receive the discharge from pumps 10. That system also has four relatively small diameter high-pressure flow lines 14 which feed into goat head 15. In contrast, the novel system shown in FIG. 2 incorporates a novel frac manifold 109 which is part of a single flow line 100. Flow line 100 carries the entire discharge from pumps 10 and runs from discharge lines 12 of pumps 10 to a junction head 115 of zipper manifold 16.

(32) Flow line 100 is shown in greater detail in FIGS. 3-5. As seen therein, flow line 100 generally comprises block offset cross junctions 120, spools 30, block cross junctions 20, valves 51 and 52, angled shims 140, and offset spools 130. It will be noted that for the sake of simplification, FIGS. 3-5 shows connections for 10 pumps 10 instead of 12 pumps 10 as shown in FIG. 2. Flow line 100 also is connected to a single well head 17 whereas in FIG. 2 flowline is illustrated as feeding into junction head 15 of zipper manifold 16.

(33) Well head 17 comprises a block tee connector 60 and a pair of manual gate valves 51. In accordance with common industry practice, many other components may be assembled into well head 17. Such components also are not illustrated for the sake of simplicity. It also will be appreciated that in the context of novel flow lines which are adapted to deliver fluid from a plurality of pump discharges to a well head, the well head not only will be considered to include such conventional well head assemblies, but also zipper manifolds and the like which may selectively divert flow into a plurality of individual well heads.

(34) Offset cross junctions 120a-120e are connected to an array of pumps 10 (not shown in FIGS. 3-5). More specifically, each offset cross junction 120a-120e is connected to two pumps 10 positioned on opposite sides of flow line 100, and are interconnected by spools 30a-30d. Offset cross junctions 120 are shown in greater detail in FIGS. 6-7. As seen therein, offset cross junctions 120 have a somewhat elongated solid rectangular body 121 having a main bore 122. Bore 122 provides the primary conduit through which slurry passes as it is conveyed towards well head 17. Bore 122 extends between opposing flat surfaces or union faces 123 on body 121. The center of bore 122 may be viewed as defining the central axis of offset cross junction 120.

(35) As appreciated from in FIG. 6, union faces 123 are provided with, for example, 16 bottomed holes 124. Holes 124 typically are threaded to accept standing bolts or other threaded connectors (not shown). Alternately, holes 124 may be adapted to receive threaded studs (not shown). Holes 124 are arranged angularly about conduit 122. When provided with studs or other threaded connectors, holes 124 allow mating components, such as spools 30 to be joined to offset cross junctions 120 by a flange-type union. More or fewer holes 124 and connectors may be provided depending upon the size of the union between the components and the pressures for which the union will be rated. Typically, union faces 123 will be provided with a metal seal (not shown) which is disposed in a groove, such as annular groove 125 extending around conduit 122. A seal is generally required to avoid leakage at union faces 123.

(36) Offset cross junctions 120 also are provided with a pair of bores 126 which provide conduits for feeding discharge from an individual pump 10 into primary bore 122. Bores 126 extend perpendicularly from opposing flat union faces 127 on body 121 and lead into and intersect with main bore 122. It will be noted that bores 126 intersect with main bore 122 at right angles as may be seen in FIG. 7. Bores 126, however, intersect with main bore 122 at axially offset junctions. As discussed further below, offsetting the junctions between feed bores 126 and primary bore 122 will help to minimize areas of concentrated erosion in cross junctions 120.

(37) Like primary union faces 123, feed union faces 127 comprise a plurality of holes is 128, in this case 8. Holes 128 allow mating components, such as pump discharge lines 12 to be joined to offset cross junctions 120 by threaded studs or other threaded connectors. Feed union faces 127 also will have a metal seal (not shown) disposed in an annular recess 129. Like union faces 123, feed union faces 127 may be varied in accordance with common practice in the art.

(38) Offset cross junctions 120a-120e are joined by spools 30a-30d. Spools 30 are conventional spools. As such they comprise a pipe which provides a conduit for conveying fluid between fittings in flow line 100, such as between cross junctions 120 and between angled shims 140a and 140b. A pair of flanges are provided at each end of the pipe. The outer flat surfaces of the flanges provide union faces. Each of the flanges is provided with, for example, 16 bolt holes extending through the flanges. The holes are adapted to accommodate the passage of threaded connectors, such as threaded studs or bolts. The holes allow spools 30 to be joined, for example, to cross junctions 120 in flow line 100. The flanges also are provided with a metal seal. The union faces on spools 30, however, may be varied as desired in accordance with common practice in the art.

(39) Offset cross junctions 120a-120e and spools 30a-30d may be viewed as a subassembly 113 of flow line 100. Though not shown in FIGS. 3-5 for the sake of simplification, it will be appreciated that flowline segment 113 typically will be mounted on a skid or trailer as part of frac manifold 109. Frac manifold 109 also may include at least one low-pressure line 8, to which will be connected low-pressure suction hoses 11 for feeding slurry to pumps 10.

(40) Discharge lines 12 of pumps 10 feed into flowline segment 113 of frac manifold 109. They may be connected to offset cross junctions 120 by various conventional unions. Discharge lines 12 may terminate in a flanged sub allowing them to be connected directly to cross junctions 120 at feed union faces 127. Alternately, a flanged, female sub 71 of a hammer union may be connected to feed union faces 127 as shown in FIGS. 3-5. Discharge lines 12 of pumps 10 then may be connected to cross junctions 120 by hammer unions.

(41) Thus, in contrast to conventional frac manifold 9, which has two relatively small manifolding missiles 13 which themselves are manifolded, novel frac manifold 109 comprises a single, larger, straight segment 113 of flowline 100 which receives the discharge from all pumps 10. That is, in conventional frac systems, such as those shown in FIG. 1, pumps 10 will be lined up on both sides of frac manifold 9. Pumps 10 on one side of frac manifold 9, as represented schematically in FIG. 1, typically will feed into the missile 13 running along that side of frac manifold 9. Pumps 10 which are lined up on the other side will feed into the missile 13 running on the other side of frac manifold 9. Missiles 13 are manifolded by a section of pipe which connects their downstream ends at right angles. The combined discharge from missiles 13 then is distributed into four high-pressure flow lines 14 which run to goat head 15.

(42) As shown schematically in FIG. 2, pumps 10 from both sides of frac manifold 109 all feed into flowline segment 113. Offset cross junctions 120 allow two pumps 10 to feed into flow line 100 from opposite sides of flowline 100. Frac manifold 109, therefore, will have a simpler, less cluttered design. It may be assembled more easily, and when in service, will allow greater access to manifold components for hook up and service. More importantly, however, novel frac manifolds incorporating a single, larger flow line section, such as segment 113, should provide better wear resistance and a longer service life than conventional frac manifolds incorporating multiple missiles.

(43) That is, the slurry flowing through flow lines is highly abrasive and corrosive, moves at relatively high velocities under high pressure, and is quite turbulent in many areas. Consequently, flowline components tend to suffer material loss which can weaken the part and shorten its service life. The material loss results from a number of different dynamics, including ductile erosion and brittle erosion, both of which are exacerbated by corrosion.

(44) Ductile erosion results from entrained sand and other particles dragging along the inner walls and cutting or ploughing into the walls. The angle of impingement typically is small, less than 30. Ductile erosion is the primary dynamic in relatively straight sections of flow lines. Brittle erosion results from entrained sand impinging on the walls at near normal to the surface, the impact causing tiny radial cracks in the wall. Brittle erosion is the primary dynamic in turbulent areas of the flow line or where the flow line changes direction.

(45) It also will be appreciated that corrosion generally tends to weaken material in the part. The part, therefore, is more susceptible to both ductile and brittle erosion. Moreover, since flowline components typically are fabricated from relatively hard steels, brittle erosion from near normal impacts caused by more turbulent flow typically plays a larger role than ductile erosion resulting from more laminar flow.

(46) For example, turbulence and brittle erosion is the primary dynamic in the area where pump discharge lines 12 feed into missiles 13 of conventional frac manifold 9. Fluid from discharge lines 12 immediately hits the other side of missile 13, which is only a few inches away. More specifically, the inner diameter of high-pressure missiles in conventional frac manifolds typically will be sized such that they cumulatively provide the required flow rates (up to 100 bbl/minute) without excessively high fluid velocity through the missiles. The upper limit, often referred to as the erosional fluid velocity, generally is about 40 ft/sec. Thus, missiles in conventional frac manifolds typically will be made up from 3 or 4 components having, respectively, inner diameters of 2.75 and 3.5.

(47) In contrast, novel flow lines having comparable flow rates and velocities will incorporate 5 or 7 1/16 components having, respectively, inner diameters of 5.13 and 7.06. Thus, for example in novel flowline segment 113, it will be appreciated that fluid entering primary bore 122 of offset cross junctions 120 from feed bores 126 will have more room to spread. The quantity and velocity of particles impinging on the other side of primary bore 122 at near normal angles will be less than experienced by smaller diameter pipes, such as missiles 13 in conventional frac manifold 9.

(48) Moreover, offsetting the junctions between feed bores 126 and primary bore 122 will help to minimize areas of concentrated turbulence and erosion in cross junctions 120, Turbulence created by fluid entering primary bore 122 from an upstream feed bore 126 will tend to diminish, and the flow will become more laminar as fluid travels down primary bore 122. Feed bores 126, therefore, preferably are spaced at sufficient distances to allow turbulence to substantially subside. For example, feed bores 126 may be offset a distance at least approximately equal to the diameter of feed bores 126, and more preferably, at a multiple thereof. Feed bores 126 as illustrated in FIGS. 6-7, for example, are offset by a factor of approximately 7 relative to their diameters.

(49) Moreover, the novel flow lines preferably, as does flow line 100, incorporate block cross junctions and other block fittings, that is, junction and directional fittings having prismatic or solid rectangular bodies. As compared to the tubular fittings from which missiles in conventional frac manifolds traditionally are assembled, block fittings, such as offset cross junction 120, provide additional thickness in conduit walls. Block fittings can tolerate more erosion before reaching a point where the integrity of the fitting is compromised.

(50) Block junctions also may easily incorporate wear sleeves. For example, offset cross junctions 220 shown in FIG. 8 is substantially identical to offset cross junction 120 except that has wear sleeves 222 and 226. Likewise, offset cross junction 320 shown in FIG. 9 is substantially identical to offset cross junction 120 except that it has wear sleeves 322 and 326. As discussed further below, such wear sleeves can provide additional resistance to erosion and wear, especially when provided in areas subject to turbulent flow. Wear sleeves also may be replaced after a period of service, thus avoiding the need to scrap an entire part.

(51) Finally, frac manifolds usually are mounted on a skid or trailer so that they may be transported easily to and from a well site. That is a significant advantage. The need to transport the manifold over roads and highways without special permits, however, limits the size of the skid or trailer platform and can create significant spatial constraints in the design and layout of the manifold. Frac manifolds having two or more missiles, such as frac manifold 9, require very sharp turns in the flow line and often more junctions. For example, each missile typically will make a right turn, or it will tee into a manifolding pipe. Such turns and junctions are particularly susceptible to erosion. They are eliminated in the novel flow lines, such as flowline segment 113, which provide a single straight flow line accepting discharge from both sides of the segment.

(52) While offset cross junctions 120 of flowline segment 113 provide many advantages, it will be appreciated that other junctions accepting feed from two or more pumps may be incorporated into the novel flow lines. For example, offset lateral cross junction 420 shown in FIGS. 10-11 may be connected to two pumps 10. Offset lateral cross junction 420 has a body 321. The main portion of body 421 has a generally cuboid shape with trapezoidal prism shaped arms extending from opposite faces. Body 421 has a main bore 422. Bore 422 provides the primary conduit through which slurry passes as it is conveyed towards well head 17. Bore 422 extends between opposing flat surfaces or union faces 423 on body 421.

(53) Offset lateral cross junctions 420 also are provided with a pair of bores 426 which provide conduits for feeding discharge from an individual pump 10 into primary bore 422. Bores 426 extend perpendicularly from flat union faces 427 on body 421 and lead into main bore 422. Primary union faces 423 and feed union faces 427 are substantially identical to union faces 123 and 127 in offset cross junction 120.

(54) It will be noted that bores 426 of offset lateral cross junction 420 intersect with main bore 422 at an interior angle, for example, 45 as shown in FIG. 11. Bores 426 also intersect with main bore 422 at axially offset junctions. Thus, it is expected that lateral cross junction 420 will provide further improvements in wear resistance and service life. Fluid entering primary bore 422 of lateral cross junctions 420 from feed bores 426 will not only have more room to spread, but will enter primary bore 422 at an angle. Particles impinging on the other side of primary bore 422 on average will impact at much shallower angles, further reducing the effects of brittle erosion.

(55) Consistent therewith, the intersection angle between feed bores 426 and primary bore 422 may be varied. Preferably, it will be less than 90. Little benefit will realized at angles near 90. More preferably, the intersection angle will be from about 30 to about 60. It also will be appreciated, as compared to the offset between feed bores 126 in offset cross junction 120, feed bores 426 in lateral cross junction 420 may be offset to a lesser degree. Since fluid is entering primary bore 422 at a shallower angle, turbulence in primary bore 422 will diminish more rapidly, and assume a more laminar flow than in primary bore 122 of offset cross junction 120.

(56) Right-angle cross junction 520, which is shown in FIGS. 12-43, also may be incorporated into flow line 100 and connected to two pumps 10. Right-angle cross junction 520 has a generally cubic body 521 having a main bore 522. Bore 522 provides the primary conduit through which slurry passes as it is conveyed towards well head 17. Bore 522 extends between opposing flat surfaces or union faces 523 on body 521.

(57) Right-angle cross junctions 520 also are provided with a pair of bores 526 which provide conduits for feeding discharge from an individual pump 10 into primary bore 522. Bores 526 extend perpendicularly from adjacent flat union faces 527 on body 521 and lead into main bore 522. Primary union faces 523 and feed union faces 527 are substantially identical to union faces 123 and 127 in offset cross junction 120.

(58) It will be noted that bores 526 in right-angle cross junctions 520 are perpendicular to each other and intersect with main bore 522 and each other at right angles. Right-angle cross junctions 520, therefore, may make it easier to assemble pump discharge lines 12 from pumps 10 on either side of cross junction 520. Consistent therewith, it will be appreciated that the angle between bores 526 may be varied. The angle may be somewhat greater or lesser than 90 and still facilitate connection of pump discharge lines 12 from pumps staged on opposite sides of cross junction 520. Bores 526 also may be offset along main bore 522, similar to offset cross junction 120, may intersect with main bore 522 at an angle, similar to offset lateral cross junction 420, or may incorporate both such features.

(59) The portion of flow line 100 extending from offset cross junction 120e to well head 17 may be viewed as a subassembly 114. Flowline segment 114, as illustrated, may incorporate additional or fewer spools 30 of varying lengths running from flowline segment 113 to make up the distance between frac manifold 109 and junction 115 of zipper manifold 16. The novel flow lines also may incorporate other conventional flow line components, units, and subassemblies. For example, flowline segment 114 incorporates cross junctions 20. Cross junctions 20 may be used to allow additional flowline components or segments to be added, such as pressure relief valves or bleed-off lines. The novel flow lines also may incorporate, for example, gauges and other monitoring equipment, as well as control devices such as shut off, plug, check, throttle, pressure release, butterfly, and choke valves. For example, flow line 100 is provided with valves 50 and 51. Valve 50 is a conventional manual gate valve. Valve 51 is a conventional hydraulic valve which may be controlled remotely.

(60) Cross junctions 20 are shown in greater detail in FIGS. 14-15. As seen therein, cross junction 20 has a generally cubic body 21 having a main bore 22. Bore 22 provides the primary conduit through which slurry passes as it is conveyed towards well head 17. Bore 22 extends between opposing flat surfaces or union faces 23 on body 21. Cross junctions 20 also are provided with a pair of bores 26 which provide conduits for feeding discharge from an individual pump 10 into primary bore 22. Bores 26 extend from opposing flat union faces 27 on body 21 and lead into and intersect with main bore 22. Primary union faces 23 and feed union faces 27 are substantially identical to union faces 123 and 127 in offset cross junction 120.

(61) It will be noted that bores 26 are aligned along their central axes and intersect with main bore 22 at right angles. Thus, it will be appreciated that cross junctions 20 may be more suitable for diverting flow from a main flow line, such as flow line 100. They may be used to connect pumps 10, but opposing high-pressure, high-velocity flows, such as the discharge from pumps 10, may create undesirable harmonics in the system and lead to excessive vibration.

(62) Flow lines necessarily must change course as flow is split or combined. Ideally, however, those portions of a flow line extending between junction fittings, would extend in a straight line. Unfortunately, that rarely, if ever, is possible. For example, as best appreciated from FIGS. 3-5, in flowline 100 junctions 120 are all aligned and extend in a straight line. Junctions 120, however, are not aligned with well head tee connector 60, nor is it necessarily practical to position pumping units 10, frac manifold 113, and other frac equipment such that they are aligned. There is a large amount of equipment at a well site, especially during fracturing operations. The flow line must be able to accommodate whatever spatial constraints are present at a site.

(63) Thus, as discussed further below, the novel flow lines may incorporate various combinations of angled shims, standard spools, and offset spools to change the direction or course of the flow line as required for a specific well site. For example, as shown in FIGS. 3-5, flow line 100 runs straight along the x-axis between offset cross junction 120a and angled shim 140a. The heading of flow line 100 may be changed by incorporating various combinations of angled shims 140, standard spools 30, and offset spools 130. Specifically, angled shims 140a-140b and offset spools 130a and 130b have been used to provide changes in the heading of flow line 100 along all three axes x, y, and z to accommodate the position of frac manifold 109 relative to well head 17.

(64) Angled shims 140 are shown in greater detail in FIGS. 16-18. As seen therein, angled shim 140 has a body 141 shaped generally like a truncated or beveled cuboid or a trapezoidal prism. Body 141 has intersecting bores 142. Bores 142 provide the primary conduit through which slurry passes as it is conveyed towards well head 17. Bores 142 extend perpendicularly inward from flat surfaces or union faces 143 and interest within body 141.

(65) As appreciated from in FIGS. 16-17, union faces 143 are provided with, for example, 16 bottomed holes 144. Holes 144 typically are threaded to accept standing bolts or other threaded connectors (not shown). Alternately, holes 124 may be adapted to receive threaded studs (not shown). Holes 144 are arranged angularly about bores 142. When provided with studs or other threaded connectors, holes 144 allow mating components, such as spools 30 to be joined to angled shims 140 by a flange-type union. More or fewer holes 144 and connectors may be provided depending upon the size of the union between the components and the pressures for which the union will be rated. Typically, union faces 143 also will be provided with a metal seal (not shown) which is disposed in a groove, such as an annular groove 145 extending around conduit 142. A seal is generally required to avoid leakage at unions at union faces 143.

(66) It will be appreciated that, like offset cross junction 120, the novel angled shims also may incorporate wear sleeves. For example, angled shim 240 shown in FIG. 19 is substantially identical to angled shim 140 except that it has wear sleeves 248. Angled shim 340 shown in FIG. 20 also is substantially identical to angled shim 140 except that is has wear sleeves 348. As discussed further below, such wear sleeves can provide resistance to erosion and increase the service life of the components.

(67) The novel angled shims are adapted to provide varying changes in the direction of flow lines by varying the angle between union faces. The extended planes of union faces 143 of angled shims 140, for example, intersect at an angle where is 45 as may be seen in FIG. 18. In other words, union faces are angled 45 relative to each other. Thus, angled shims 140 can provide a 45 turn in flow line 100. For example, as shown in FIGS. 3-5, flow line 100 extends along the x-axis up to angled shim 140a . Angled shims 140a and 140b are coupled by spool 30i and allow flow line 100 to first veer right (45) and then to veer right again (45) such that flow line 100 now heads along they-axis. In simple terms, angled shims 140a and 140b have allowed flow line 100 to make a right turn.

(68) The angle between the union faces of the novel angled shims may be varied as desired. For example, angle may be 30 or 22.5 to provide more gradual changes in direction. Angle may be, but typically will not be greater than 45 as such angles produce more severe changes in direction.

(69) It will be appreciated that angled shims 140, as well as block junctions 120, 220, and 520, have been described as having a prismatic shape, or as cuboid, solid-rectangular and the like. Angled shims 140 in fact have a generally prismatic profile, a common geometric definition of the term being a solid geometric figure whose two end faces are similar, equal, and parallel rectilinear figures, and whose sides are parallelograms. Such geometric terms as used herein are intended to describe generally the shape of such block fittings and to distinguish them from fittings which have a pipe-like or generally cylindrical body. The terms are not intended to be limited to the precise geometric definitions. For example, such components would never be fabricated without rounds along the edges, nor is it necessarily essential that opposing faces be exactly parallel or exactly the same. The precise shape may be varied consistent with the purposes described herein.

(70) Offset spools 130 are shown in greater detail in FIGS. 21-23. As seen therein, offset spools 130 comprise in large part a pipe 131 which provides a conduit 132 for conveying fluid between junction and directional fittings in flow line 100, such as between angled shims 140b and 140c and between angled shim 140d and block tee junction 60 in well head 17. A pair of flanges 133 are provided at each end of pipe 131. The outer flat surfaces of flanges 133 provide union faces. Each flange 133 is provided with, for example, 16 bolt holes 134 extending through flanges 133. Holes 134 are adapted to accommodate the passage of threaded connectors, such as threaded studs or bolts. Holes 134 are arranged angularly on flanges 133 about conduit 132, and thus allow offset spools 130 to be joined to other flowline components, such as shims 140d and block tee junction 60 in flow line 100.

(71) Though described as flat herein and appealing to the casual observers as such, typically flanges 133 will have a very shallow annular boss extending around the pipe conduit. Upon careful inspection, the annular boss may be seen in FIG. 23. A metal seal (not shown) is disposed in an annular groove 135 extending around conduit 132 on the shallow, annular boss. Annular boss will help ensure that the abutment between mating union faces is properly loaded when the union is made up. The designs and features of union faces in particular and flange unions in general are well known, however, and the union faces on flanges 133 may be varied in accordance with common practice in the art.

(72) In such respects, offset spools 130 are identical to conventional spools 30. Unlike conventional spools, however, bolt holes 134 on each flange 133 are offset from each other. That is, in conventional spools the bolt holes on one flange are aligned angularly with the bolt holes on the other flange. In other words, if there are 16 bolt holes, the bolt holes on each flange will be spaced radially at 22.5 increments starting at 0.

(73) Bolt holes 134 on flanges 133 of offset spools 130 also are spaced angularly at 2.5. As best appreciated from FIG. 22, however, the array of bolt holes 134a (shown in phantom) on flange 133a and the array of bolt holes 134b on flange 133b are offset relative to each other by an angle . In offset spool 130 angle is 11.25, thus offsetting bolt holes 134a and 134b by 11.25. Thus, the array of holes 134a on flange 133a will start at 0, and the array of holes 134b on flange 133b will start at 11.25.

(74) It will be appreciated, therefore, that offset spools 130 also may be used to provide a change of direction in flow line 100. As appreciated best from FIGS. 3 and 5, angled shims 140b and 140c are joined by offset spool 130a . Offset spool 130a allows angled shim 140c to be rotated 11.25 off of the z-axis relative to angled shim 140b . Shim 140c , therefore, will allow flow line 100 not only to veer up (approximately 45), but to veer left (11.25).

(75) Further down flowline segment 114, angled shim 140d is connected to angled shim 140c by conventional spools 30j and 30k. The bolt holes in conventional spools 30j and 30k are not offset. Thus, angled shim 140d also is rotated 11.25 off of the z-axis, and the studs on angled shim 140d will be offset relative to those on tee junction 60. Offset spool 130b will allow angled shim 140d to be connected to tee junction 60, and angled shim 140d will allow flow line to veer down (approximately 45) and to veer right (11.25).

(76) Flowline segment 114 thus returns to its prior heading along the y-axis (between angled shims 140b and 140c ), but at a higher elevation equal to that of tee junction 60. More simply, angled shims 140c and 140d and offset spools 130a and 130b allow flowline segment 114 to deviate up and to the left and then down and to the right to establish a flow line between angled shim 140b and tee junction 60.

(77) The novel offset spools of the subject invention will allow greater control over the angular alignment of components in a flowline and, therefore, over the direction (or heading) and course (or track) of a flowline. Conventional spools have been used to provide relative rotation of components connected to opposite ends of the spool. Relative rotation can be achieved simply by rotating the array of bolts on the second component relative to its normal position. For example, if a component has 16 studs passing through 16 holes on the spool, relative rotation may be achieved in increments of 22.5.

(78) If used in combination with offset spools, however, relative rotation may be achieved in finer increments. When used in combination with conventional 16-bolt spools, offset spools 130 will allow relative rotation in increments of 11.25. A component may be rotated a factor of 22.5 or 45, for example, by using a standard spool. An offset spool 130 may be used to rotate the component by a factor of 22.5 plus or minus 11.25, for example 11.25, 33.75, or 56.25. Thus, by selectively using either a standard or an offset spool 130, components connected to the ends of the spool may be provided with relative rotation in increments of 11.25.

(79) It will be appreciated that the novel spools may be offset by varying degrees. For example, and again using a conventional 16-bolt spool as the frame of reference, the offset angle may be 7.5. By selectively using combinations of standard and offset spools, relative rotation may be provided in increments of 7.5. A component may be rotated a factor of 22.5 by using a standard spool. An offset spool may be used to rotate the component by a factor of 22.5 plus or minus 7.5, or two offset spools may be used to rotate the component by a factor of 22.5 plus or minus 15.

(80) Likewise, offset spools may be provided with different numbers of bolt holes as is common for standard spools, such as 8, 10, or 12 holes. For example, using a 12-bolt spool as the frame of reference where the holes are spaced at 30, the offset angle may be, for example, 15 or 10. Using an 8-bolt spool with 45 spacing as the frame of reference, the offset angle may be, for example, 22.5, 15, 11.25, or 7.5. It also will be appreciated that other flanged components or block fittings having union faces may be offset. For example, bottomed holes 144 on union faces 143 of angled shims 140 may be offset relative to each other. Relative rotation between components connected to angled shims 140, therefore, may be achieved as with offset spools 130. Similarly, cross junction 20 and tee connector 60 may be provided with offset connector holes. For inventory purposes, however, it may be less desirable to offset other flow line fittings and components.

(81) It will be appreciated that the novel flowline components have been exemplified largely in the context of assembling flow lines through flange unions. That is, block fittings such as offset cross junction 120 and angled shim 140 have been exemplified as having union faces adapted for connection to another flowline component by a flange union. If desired, however, other types of unions may be used in the novel flow lines. Flanged hammer union or clamp union subs may be joined to a block fitting by a flange union, allowing additional components to be joined by a hammer union or a clamp union. A hammer union sub or a clamp union sub also may be provided integrally on the novel block fittings if desired, although as noted below, various advantages may be gained by assembling the novel flow lines with flange unions.

(82) The flowline components of the subject invention may be fabricated by methods and from materials commonly used in manufacturing flow iron components. Given the extreme stress and the corrosive and abrasive fluids to which flowline components are exposed, especially those designed for high-pressure, high-velocity flow lines, suitable materials will be hard and strong. For example, offset cross junctions 120, spools 30, offset spools 130, and angled shims 140, except for their seals, may be fabricated from 4130 and 4140 chromoly steel or from somewhat harder, stronger steel such as 4130M7, high end nickel alloys, and stainless steel. The components may be made by any number of conventional techniques, but typically and in large part will be made by forging, extruding, or mold casting a blank part and then machining the required features into the part.

(83) As noted above, however, the flow through the high-pressure side of frac systems can be quite turbulent, especially at the unions between flowline components. The flowline components, therefore, may incorporate a wear sleeve. As noted above, offset cross junctions 220 and 230 have, respectively, wear sleeves 222/226 and 322/326. Angled shims 240 and 340 have, respectively, wear sleeves 248 and 348. Lateral cross junctions 420, right-angle cross junctions 520, and cross junctions 20 also may be provided with wear sleeves. Offset spool 130 is provided with wear sleeves 138, as may be standard spools 30.

(84) Offset spool 130 provides a more specific example of how such wear sleeves may be incorporated into the novel components. Wear sleeves 138 of offset spool 130, as their name implies and as may be seen in FIG. 23, have an open cylindrical shape. Wear sleeves 138 are carried in annular recesses in conduit 132 of offset spool 130. They extend axially rearward from the union faces of flanges 133.

(85) Wear sleeves 138 define in part bore 132 extending through offset spool 130, but will be fabricated from more wear resistant materials than those used elsewhere in offset spool 130. For example, wear sleeve 138 may be fabricated from tungsten carbide steel alloys, borided steel, carburized steel, stainless steel, or diamond coated steel.

(86) Wear sleeves 138 may be mounted within offset spool 130 in various ways. For example, they may be relatively loose fitting, and elastomeric O-rings may be provided between wear sleeve 138 and the recess if desired. They may be more closely dimensioned to the recess such that wear sleeves 138 are held securely within offset spool 130 by an interference fit. A tighter interference fit may be provided by shrink fitting sleeves 138 within the recesses. Sleeves 138 also may be welded or brazed into the recesses. Preferably, however, they will be installed in spools 130 such that they may be replaced after a period of service and thereby extend the overall service life of spools 130.

(87) Wear sleeves 138 may extend through the major areas of bore 132 of offset spool 130 where turbulent flow occurs. The precise length of wear sleeves 138 in conduit 132, as well as the length and extent of wear sleeves in other novel components, therefore, may be varied.

(88) For example, angled shim 240 shown in FIG. 19 has a pair of wear sleeves 248. Wear sleeves 248 are similar in many respects to wear sleeves 138 of offset spools 130. They are fabricated from more wear resistant materials and may be mounted therein in similar ways. The inner ends of wear sleeves 248, however, are provided with mating bevels such that wear sleeves 248 extend through the entire course of the bores in angled shim 240. Other flowline components, such as offset cross junctions 120, offset lateral cross junctions 420, tight-angle cross junctions 520, and cross junctions 20, also may be provided with wear sleeves extending the length of their primary bores. Given the typical length of spools, it may not often be the case, but offset spools 130 and standard spools 30 also may be provided with wear sleeves along their entire conduit.

(89) It also will be appreciated that turbulence created in one component may extend into another component to which it is joined. The novel flow line components, therefore, also may be provided with wear sleeves that extend across unions between components. For example, as shown in FIG. 20, angled shim 340 is provided with a pair of wear sleeves 348a and 348b. Wear sleeves 348 may be fabricated and installed as are wear sleeves 248 in angled shim 240. Like wear sleeve 248a in angled shim 240, angled shim 348a in angled shim 340 extends along the length of its bore. Wear sleeve 348b, however, extends beyond its bore and the corresponding union face 143 in angled shim 340. When angled shim 340 is joined, for example, to an offset spool 130 (shown in phantom), wear sleeve 348b will extend into a recess provided in spool 130. Spool 130, therefore, is provided with protection from turbulence generated within angled shim 340.

(90) Other flowline components also may be provided with wear sleeves which span the union with other flowline components. For example, offset spools 230 shown in FIG. 24 are provided with a wear sleeve 238 which extends across the union between them. Wear sleeve 238 may be carried in offset spools 230 in the same fashion as in angled shim 240. Offset cross junctions 220 and 320 shown, respectively, in FIGS. 8 and 9 also incorporate, respectively, wear sleeves 222 and 322 which can span the union with other flowline components. Lateral cross junctions 420, right-angel cross junctions 520, cross junctions 20, and spools 30 also may incorporate spanning wear sleeves.

(91) Such spanning wear sleeves, however, offer other options for incorporating them into flow line components. For example, offset spools 330 shown in FIG. 25 are provided with a spanning wear sleeve 338. Like wear sleeve 238 in offset spools 230, wear sleeve 338 in offset spools 330 spans the union between them. In contrast, however, wear sleeve 338 has an integral annular metal seal 339 which extends radially from the midsection thereof. Metal seal 339 has a thinned-out portion around which extends the seal portion. Metal seal 339 is sized to fit into mating annular grooves 335 in flanges 133 which extend around conduit 132 on a shallow, annular boss. Metal seal 339, like wear sleeve 338, will be fabricated from harder materials than those used elsewhere in offset spools 330. Thus, s the softer metal from spools 330 will deform and seal against seal 339. Similar wear sleeve designs may be incorporated into other flowline components designed for flange unions.

(92) It also will be appreciated that turbulence is created at unions with feed bores in block junctions. Thus, the feed bores in block junctions such as offset cross junctions 120, lateral cross junctions 420, right-angle cross junctions 520, and cross junctions 20 may be provided with wear sleeves. For example, wear sleeves 226 are provided in feed bores of offset cross junction 220 shown in FIG. 8. Offset cross junction 320 shown in FIG. 9 also has wear sleeves 326 in its feed bores. It will be noted that wear sleeves 226 and 326 in, respectively, offset cross junctions 220 and 320 are designed to span the union with, e.g., the discharge hoses 12 of pumps 10.

(93) As is apparent from the exemplified embodiments shown in FIGS. 8-9 and 19-25, the various design features incorporated into the wear sleeves may be varied extensively and combined in various ways. It also will be appreciated that such design features are not limited to the preferred, exemplified embodiments. They are generally suited for use in other flowline components joined by flange unions. In any event, it will be appreciated that by incorporating wear sleeves as exemplified herein, erosion of the novel flowline components may be reduced. Service life of the components also may be increased by periodically replacing the wear sleeves.

(94) Though the course of a particular flow line will vary greatly depending on the equipment used and the well site, it also will be appreciated that the novel flow lines may provide a single, relatively large flowline over much of the high-pressure side of a frac system. Flow line 100, for example, runs from pump discharges lines 12 all the way to well head 17. Such flow lines offer various advantages.

(95) First, the overall layout at a well site is greatly simplified. Simplification of the frac system can create space to access other portions of the system and reduce confusion among workers at the site. Moreover, by replacing multiple lines with a single line, the total number of components in the system may be reduced. Fewer components mean fewer junctions and fewer potential leak and failure points in the system. Fewer components also means less assembly time at a well site.

(96) Second, exposed elastomeric seals are a potential source of leaks. They also increase turbulence through a conduit and, therefore, erosion resulting from the flow of abrasive slurry through the flow line. The novel flow lines, however, preferably are assembled using flange unions. Flange unions do not have any exposed elastomeric seals. They have internal metal seals situated between the union faces. Thus, preferred block fittings, such as offset cross junctions 130 and angled shims 140, have union faces adapted for flange unions, and flow line 100 does not have any exposed elastomeric seals other than those that necessarily may be present in components such as control valves.

(97) It will be noted in particular that preferred flow lines, such as flow line 100, are able to accommodate changes in direction without conventional directional fittings such as elbows, but especially without using swivel joints. Swivel joints are expensive. They incorporate elastomeric seals and packings. They also have sharp turns which are particularly susceptible to erosion. Moreover, they are particularly susceptible to bending stress caused by vibrations in the flow line. Such strain can lead to failure. In any event, it means that swivel joints have a relatively shorter service life than many flow line components. Thus, swivel joints not only are a big component of the overall cost of a flow line, but they are a primary source of potential leaks and failure.

(98) The relatively large inner diameter of the novel flowlines such as flow line 100 can help minimize erosion and failure in other ways. As the diameter of a conduit increases, drag on the fluid passing through the conduit increases, but not as rapidly as the volume of fluid. Thus, proportionally there is less drag, and flow through the conduit is more laminar. Moreover, by replacing multiple smaller lines with a single larger line, overall drag on fluid conveyed through the system is reduced. For example, a single 7 1/16 line may replace six 3 lines. The drag through the larger line will be less than half the cumulative drag through the six smaller lines. More importantly, less drag means less erosion.

(99) In addition, the novel flow lines, such as flow line 100, may incorporate more gradual changes in directions. Swivel joints and other conventional fittings have relatively sharp turns and changes in direction. The gradual turns of flow line 100, for example, will tend to reduce the angle of impingement of abrasive particles on the conduit walls. The flow line, therefore, will tend to suffer less brittle erosion.

(100) Perhaps most importantly, the relatively large diameter of, and the more gradual turns in the novel flow lines such as flow line 100, may create the opportunity for on-site inspection. That is, there are various conventional systems which allow inspection of the inside of pipelines used to transport oil and gas. Such pipelines typically have larger internal diameters and fewer turns, especially sharp turns, than are present in frac systems. Such in-line inspection (ILI) systems include cameras which are deployed into a conduit to visually inspect the internal walls for defects. The capabilities of visual ILI systems may be enhanced by using penetrating dyes. Magnetic-flux leakage, magnetic particle, and electromagnetic acoustic transducer ILI systems also may be deployed to detect electromagnetic anomalies caused by corrosion and erosion. Pit gauges, calipers, or 3-D laser (LIDAR) systems also may be deployed to map the surface of the conduit.

(101) Many of those systems and techniques are used to inspect components at off-site production or certification facilities. The use of conventional ILI systems on site, however, is extremely limited or nonexistent in conventional flow lines used in frac systems. Conventional frac systems typically employ too many relatively small flow lines having a relatively high number of relatively sharp turns. It is difficult or impossible to run conventional ILI equipment through much, if not all of the system.

(102) By using a single, relatively large flow line with more gradual bends, however, various embodiments of the invention make such in-line inspection techniques possible. For example, flow line 100 has a single, relatively large diameter flow line running all the way from discharge lines 12 of pumps 10 to well head 17. Typically, flow line 100 will be made up of nominal 7 1/16 or 5 components having, respectively, inner diameters of 7.06 and 5.13. The bends in flow line 100 between hydraulic valve 51 and well head 17 are gradual. There are no 90 turns. Thus, many conventional in-line inspections systems may be run into flow line 100 as assembled at a well site.

(103) The novel single line frac system preferably will be installed within and supported by a modular skid system. The skids are designed to restrict movement of flowline components if the union between the components fail. In addition, the skids are adjustable. Components carried within the skid may be adjusted along three axes to allow easy and precise positioning to facilitate assembly of the flow line. The skids are modular, and may be interconnected to facilitate transportation of the flow line in pre-assembled. subassemblies to the site.

(104) A preferred embodiment 160 of the skids of the subject invention is shown in FIGS. 20-22. As shown therein, a flowline subassembly 101 has been loaded within skid 160. Subassembly 101 generally comprises two cross junctions 20 which are connected by a spool 30. Flanged female subs 71 of a hammer union sub are connected to feed union faces 27 of cross junctions 20. Subassembly 101 will be installed in flow line 100 as described further below.

(105) Skid 160 generally comprises a base 161, a carriage 162, an assembly stand 163, a lift 164, and a cage 165. Base 161 is a rugged, heavy a frame-like structure comprising various lateral and cross members fabricated, for example, by welding steel tubing, bars, or other structural members together. It serves a primary purpose of providing a foundation for skid 160. Consistent with that purpose, it may have a variety of design configurations. Generally, it will have a frame-like structure, but it may be a solid plate. A base also may be provided by separate feet having a sufficiently large footprint to support the substantial weight of skid 160 and flowline subassemblies, such as subassembly 101.

(106) Carriage 162 is illustrated as a plate-like part, but it can have a frame-like structure. It is supported on base 161 by four linear actuators 166. Preferably, linear actuators are hydraulic cylinders, and it will be appreciated that hydraulic lines and other conventional components of hydraulic systems have been omitted from FIGS. 26-28 for the sake of clarity. Frac sites are not always level or graded to specification. Actuators 166, therefore, preferably may be controlled by conventional control systems to level carriage 162. In any event, actuators 166 may be controlled to raise and lower carriage 162 over base 161 and, thereby, to raise and lower subassembly 101 relative to grade. It will be appreciated, however, that other linear actuators, such as electric motors, may be used if desired.

(107) Carriage 162 also comprises bearing surfaces which allow subassembly 101 to be moved horizontally across carriage 162 along at least two intersecting axes so that subassembly 101 to be positioned anywhere on carriage 162. Subassembly 101 typically will be quite heavy, and therefore, the bearing surface should have a sufficiently low coefficient of friction so that subassembly 101 may be moved manually across carriage 162 by workers on site. Thus, for example, carriage 162 is provided with a plurality of ball transfer units 167 that allow free and easy movement of subassembly 101. A variety of conventional ball transfer units are known and commercially available and may be mounted to carriage 162 by conventional means. Raceways also may be machined into the bottom plate of carriage 162 and ball bearings packed therein. Other types of bearings may be provided as well. Given that subassembly 101 will be moved about carriage 162, carriage 162 preferably is provided with a rim, as seen best in FIG. 25, or tabs or some other interfering structure to limit movement of subassembly 101 across carriage 162.

(108) Subassembly 101 preferably, as seen best in FIG. 26, is supported on an assembly stand 163. Assembly stand 163 has a plate-like base 168 from which extend a pair of frame pedestals 169. Subassembly 101 is supported on pedestals 169 well above carriage 162.

(109) Lift 164 comprises a beam 171 and a pair of semi-circular, conventional bearing races 172 mounted at each end thereof. Beam 171, as its name implies, is an elongated support member. It provides support or a base upon which bearing races 172 may be mounted. Thus, its precise design and configuration may be varied considerably. Bearing races 172 generally conform to and are aligned with the flanges on spool 30 so that, as described below, they may engage the flanges and support subassembly 101. Bearing races 172 may be, for example, needle roller bearings.

(110) Lift 164 also comprises a linear actuator 173. Linear actuator 173 is mounted between assembly stand base 168 and lift beam 171, and may be actuated to raise or lower lift 164 relative to assembly stand 163. It will be appreciated that as shown in FIGS. 26-27, lift 164 is in a lower position in which it is at least minimally below subassembly 100 on stand 163. More specifically, bearing races 172 preferably will be at least slightly below the flanges on spool 30. The weight of subassembly 101 thus will be supported by assembly stand 163 and unnecessary wear and tear on bearing races 172 will be avoided. When lift 164 is raised, however, bearing races 172 will engage the flanges of spool 30, allowing subassembly 101 to be lifted well above assembly stand 163. Subassembly 101 then may be rotated on bearing races 172.

(111) Preferably, as does skid 160, the novel skids also will be provided with an upper cage which allows access to subassembly 101 but, in the event of severe, unexpected movement or disruption of flow line 100, will at least partially limit movement of subassembly 101 off and away from skid 160. Thus, cage 165 of skid 160 extends upward from base 161 and over subassembly 101. In particular, frame members 174 are connected to and extend vertically from base 161. Horizontal frame members 175 extend across the top ends of vertical frame members 174. Thus, cage 165 allows a substantial degree of freedom in adjusting the position of subassembly 101 within skid 160, but will significantly restrict violent movement of subassembly off of skid 160.

(112) Horizontal frame members 175 preferably are releasably connected to vertical frame members 174. For example, vertical frame members 174 and horizontal frame members 175 may be provided with mating holes and secured together by pins 176. The releasable connection allows horizontal frame members to be temporarily disassembled from skid 160 to provide greater access to subassembly 101. For example, removing horizontal frame members 175 will allow subassembly 101 to be raised high enough to allow rotation of subassembly 101. At the same time, when assembled into skid 160, horizontal frame members 175 allow cage 165 to significantly restrict movement of subassembly off of skid 160.

(113) Many other cage designs and configurations may be adopted, however, consistent with such purposes. For example, the horizontal frame members may curve over the top of subassembly 101. Horizontal and vertical are used in describing the cage feature because in large part straight frame members are more easily fabricated and assembled. The terms should be understood, however, as including frame members which extend over and on each side of a subassembly carried on the skid.

(114) The novel skids preferably are modular, and thus will be provided with features which facilitate transportation of the skids and assembly with other skids. Skid 160, for example, is provided with loading ears 177 on horizontal frame members 175. Loading ears 177 allow a lift to connect to, pick up, and move skid 160 about as required to transport skid 160 to and from a site and to assemble and disassemble flow line 100. Skid 160 also has connection tabs 178 extending laterally away from base 161. Connection tabs 178 are provided with holes. Thus, skids 160 may be assembled together by aligning tabs 178 with tabs 178 on an adjacent skid 160, and inserting a retaining pin (not shown) in the holes. Tabs 178 and pins provide a simple, reliable system for easily coupling and uncoupling a series of skids, but other designs may be used. Similarly, skids 160 may be connected via linkages, including linkages which may be adjustable to accommodate variation in the relative positions of the skids.

(115) It will be appreciated, therefore, that skids 160 can allow flow line 100 to be assembled more efficiently, effectively, and at lower overall cost. Like any conventional skid system, skids 160 allow most components of flow line 100 to be assembled into subassemblies off site. Assembly of the components may be managed, controlled, and systemized more easily in an off-site facility, and usually much closer to specification. Unlike many conventional skid systems, however, the novel systems allow for easy assembly of the flow line on site.

(116) Flow line 100, for example, may be designed off site to meet the requirements of a particular fracturing system and operation. The required parts will be determined as will the layout of flow line 100. Most of the required components, such as offset cross junctions 120, spools 30, angled shims 140, and offset spools 130, then may be assembled into subassemblies and loaded onto skids 160. Once transported to the site, skids 160 will be laid out generally in the required order, but they do not have to be located with a high degree of precision. Even with modern lifting equipment, that is a difficult task. Skids 160, however, allow subassembly 101 to be adjusted in any direction. It may be leveled, raised, lowered, and moved across carriage 162 as needed to make up flow line 100.

(117) As noted previously, skid 160 also allows flowline subassemblies to be rotated. Erosion and general wear is not symmetrically distributed through a flow line. The bottom portions of a flow line will experience greater wear over its service life than the upper portions. Thus, the novel skids, such as skid 160, will allow a flow line to be rotated periodically without disassembling the entire flow line. Erosion may be distributed more evenly through the components, thus allowing the service life of the components to be extended.

(118) It will be appreciated, of course, that the novel skids provide additional advantages in applying the novel flow lines and components. They may be used, however, in the context of conventional flow lines. Similarly, the novel flow lines and components have been described in the context of frac systems. While frac systems in particular and the oil and gas industry in general rely on temporary flow lines, the novel unions are not limited to such applications or industries. Suffice it to say that the novel flow lines and components have wide applicability in those fluid transportation systems where temporary flow lines have been conventionally applied.

(119) While this invention has been disclosed and discussed primarily in terms of specific embodiments thereof, it is not intended to be limited thereto. Other modifications and embodiments will be apparent to the worker in the art.