Modular fluid delivery system with vertically oriented valve stacks for continuous fracturing operations

Abstract

A fluid delivery system for continuous hydraulic fracturing operations includes a main fluid distribution line and a plurality of fluid inlet paths. Each inlet path features a vertically oriented valve stack with at least two isolation valves arranged in series along a vertical flow path. This vertical orientation utilizes gravity to reduce proppant accumulation and abrasive wear within the valves, enhancing system reliability. The system is configured to allow fluid conduits connecting pump clusters to the top of the valve stacks to be oriented at a variety of user-selectable, non-orthogonal angles, providing flexibility for equipment layout on a constrained well pad. A bleed-off circuit located between the isolation valves enables the safe isolation and depressurization of individual pump clusters for maintenance without interrupting the overall pumping operation. The system can be deployed with a traditional missile line or connected directly to a zipper trunk line to reduce cost and complexity.

Description

BACKGROUND OF THE INVENTIONField of the Invention

[0001] The present invention relates generally to systems and methods for high-pressure fluid delivery in the field of oil and gas well stimulation. More specifically, the invention pertains to an improved manifold apparatus for connecting multiple high-pressure pumping units to a main fluid distribution line, such as a missile or a zipper manifold, for use in continuous hydraulic fracturing operations.Description of the Related Art

[0002] Hydraulic fracturing is a well-stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of fracturing fluid into a wellbore to create cracks in deep-rock formations. To deliver the immense volumes of fluid at the required high pressures, large fleets of high-horsepower pumping units are assembled on the well site. Key components in modern fracking operations include "missile lines" and "zipper lines," which are central to the efficient and continuous delivery of fracturing fluids to the wellbore.

[0003] Surface pressures can range from a few thousand to over 15,000 pounds per square inch (psi). These pressures are necessary to overcome the natural stresses of the rock formations deep underground. The fluid is pumped down the well at impressive velocities, with flow rates for a single well typically ranging from 80 to 120 barrels per minute (BPM). In larger operations, manifold systems are designed to handle aggregate flow rates that can exceed 160 BPM.

[0004] In modern multi-well pad operations, a method known as "zipper fracturing" is often employed. A zipper line is the final high pressure distribution manifold or line located near the wellheads on a multi-well pad. It is used specifically for "zipper fracturing" operations, where stimulation jobs are alternated between two or more adjacent wells to increase efficiency. The "zipper manifold" is the key piece of equipment that facilitates this rapid switching of the high-pressure fluid stream. It is a more complex manifold system with a series of high-pressure valves that can quickly divert the flow from the missile to different wellheads. The zipper line contains the necessary valves and crossovers to rapidly switch the high-pressure fluid flow from the main feed (like a missile) to one well while the other well is being prepared for the next stage, and vice versa. It is the component that directly "zips" the treatment back and forth between wells.

[0005] The main lines of a zipper manifold are comparable in size to the missile's main bore, typically in the 5 to 7 1 / 16-inch range to handle the full flow of the frac fleet. The individual lines branching off to each wellhead are also of a similar substantial diameter. The entire system is comprised of the same high-pressure "frac iron" used throughout the high-pressure side of the operation. As with the missile manifold, the components of a zipper manifold are made from high-strength forged steel alloys capable of withstanding the demanding conditions of high-pressure, abrasive fluid flow. The integrity of these components is paramount to the safety and efficiency of the entire fracking operation.

[0006] In a typical multi-pump fracking setup, the "missile" or "missile manifold" serves as the central distribution hub or main high pressure distribution line. It's a large, robust manifold that receives the high-pressure discharge from multiple frac pumps and directs the combined, high-volume flow stream towards the wellhead. The main bore of a missile manifold is typically in the range of 5 to 7 1 / 16 inches in diameter. The individual inlet lines from each pump, often referred to as "frac iron" or "treating iron," may be the same or smaller, commonly with diameters of 3 to 4 inches. This "iron" is not cast iron but rather a collection of high-pressure steel pipes, swivels, and fittings designed to withstand the extreme operational parameters.

[0007] Given the immense pressures and the abrasive nature of the sand-laden fracturing fluid, the materials used for missile manifolds and associated piping are critical. They are constructed from high-strength, forged steel alloys, such as AISI 4130 or similar grades, which are specifically designed for high-pressure and erosive service.

[0008] A missile (or missile line) is a large-diameter, high-pressure, horizontal pipe that acts as the central "spine" or main distribution manifold on a hydraulic fracturing site. Its primary function is to: collect high-pressure fluid from multiple frac pumps or pump clusters and convey that combined fluid stream to a single point before it is directed to the wellheads (often via a zipper manifold).

[0009] This system requires a robust fluid distribution system capable of handling high flow rates and high pressures to supply abrasive, proppant-laden fluids to the wellbore being treated. The current industry standard for this fluid distribution involves a large, central, high-pressure conduit, commonly referred to as a "missile" or "trunk line". This missile acts as a spine, receiving fluid from multiple inlet branches that are connected to clusters of fracturing pumps. Each inlet branch is typically equipped with isolation valves that allow a specific cluster of pumps to be taken offline for service or maintenance while the other pumps continue to operate, enabling "continuous pumping".

[0010] The prior art includes U.S. Patent Nos. 9,932,800 and 10,385,645 that disclose a fracturing system. In one embodiment, the fracturing system includes a fracturing manifold for routing fracturing fluid to multiple wells. The fracturing manifold can be coupled via fluid conduits to fracturing trees installed at the wells. In some cases, each fracturing tree that is coupled to the fracturing manifold is coupled by at least one rigid fluid conduit. The fracturing manifold can include a trunk line that provides fracturing fluid to multiple outlet branches, which can include valves for controlling flow of fracturing fluid to wells downstream of the valves. Additional systems, devices, and methods are also disclosed.

[0011] U.S. Patent Application Publication No. 2024 / 0026765 discloses an illustrative modular manifold system that includes, among other things, two or more modular pump manifolds, a low-pressure header, and a main high-pressure manifold. Modular pump manifolds may include a low-pressure manifold for supplying fracturing fluid or water to pumps, a high-pressure manifold for supplying fracturing fluid or water to one or more wells and a bleed-off / prime-up manifold. Each modular pump manifold of the modular manifold system is configured to be fluidly isolatable from the other modular pump manifolds. Each isolated modular pump manifold is configured to be flushed with water, bled off and primed up independently of the other modular pump manifolds. After the bleed off, maintenance procedures may be performed on pumps associated with the isolated modular pump manifold. The modular pump manifolds that are not isolated may continue in active fracking stage operations while a modular pump manifold is isolated.Problems of the Prior Art

[0012] While functional, these conventional systems, which are typically arranged in a horizontal or planar layout, suffer from several significant operational and economic drawbacks.

[0013] Sand Accumulation: A primary issue is sand accumulation. During pauses in pumping, proppant (sand) settles out due to gravity and accumulates in the bottom of the valve bodies. This accumulation is believed to lead to the possibility of severe abrasive wear that may cause catastrophic failure.

[0014] Inflexible Footprint: Another significant limitation is the physical layout, or "footprint," of the equipment on the well pad. Conventional manifold systems are rigid, typically offering only fixed 90-degree or 45-degree connections. Well pads are often congested, creating "footprint challenges" that make it difficult to position the pumps and piping optimally. To accommodate these constraints, operators are often forced to use long runs of flexible high-pressure hose to create the necessary bends and connections.

[0015] High Cost and Equipment Wear: The central missile itself represents a substantial operational cost. This large and specialized piece of equipment is often rented, with rental costs cited to be as high as $90,000 per month. The use of flex hoses for "curve corrections" also increases wear and tear on the overall system.

[0016] Therefore, a need exists in the art for a fluid delivery system that inherently mitigates sand accumulation, especially in the isolation gate valves, and provides flexibility in equipment layout, maintains continuous pumping capabilities, and reduces operational cost.SUMMARY OF THE INVENTION

[0017] The present invention provides a modular fluid delivery system and method for continuous hydraulic fracturing operations that overcomes the limitations of the prior art. The system is designed to improve reliability, reduce maintenance, increase operational flexibility, and lower costs.

[0018] One embodiment of the invention is a system that utilizes vertically oriented valve stacks to connect frac pumps to a main fluid line. Each fluid inlet path comprises a vertically oriented valve stack that includes at least two large-bore isolation valves arranged in series along a vertical axis, creating a vertical flow path. This vertical orientation uses gravity to ensure proppant and debris are effectively cleared from the valve bodies, preventing the accumulation and wear seen in horizontal valves. By large bore valve it is meant the valve bore corresponds in size to the missile or zipper line e.g. which may typically be between five and seven or eight inches. As used herein terms such as “vertical” and “horizontal” refer to the orientation with respect to the ground plane.

[0019] Another key innovation is the system's flexibility in accommodating rig site layouts. The design allows rigid pipes from the pumps to be connected to the top of each valve stack at various user-selectable acute, obtuse, or right angles. This gives operators the ability to adapt to well pad constraints and create more efficient layouts without the need for failure-prone flexible hoses.

[0020] With more reliable higher rated rigid pipes, the system maintains the critical capability for continuous pumping, allowing individual pumps to be isolated for maintenance via the dual isolation valves and a dedicated bleed-off circuit, all while the rest of the operation continues uninterrupted.

[0021] In a particularly advantageous embodiment, the vertical valve stacks can be connected directly to the zipper trunk line at the wellheads. This configuration completely eliminates the need for the large, expensive missile line, thereby dramatically reducing rental costs, the number of connections, and the overall system footprint.

[0022] a. Implementations may include one or more of the following features: the fluid delivery system where each of said plurality of fluid inlet paths further may include a fluid conduit connecting the fluid source to a top of said vertically oriented gate valve stack, and where said fluid conduit is selectively connectable to said top at a plurality of different angles, said plurality of different angles including non-orthogonal angles. Each said vertically oriented gate valve stack further may include a bleed-off circuit fluidly coupled to the vertical flow path at a location between the first isolation gate valve and the second isolation gate valve, said bleed-off circuit including a bleed valve. The main fluid distribution line is a missile line configured to supply the high-pressure fracturing fluid to a zipper manifold. The main fluid distribution line is a zipper trunk line configured to supply the high-pressure fracturing fluid directly to a plurality of wellheads. Said first isolation gate valve and second isolation gate valve are large-bore gate valves. Implementations of the described techniques for operating hydraulic controls during a fracking operation may include hardware, a method or process, or computer software on a computer-accessible medium.

[0023] Another general aspect includes a fluid delivery system for hydraulic fracturing operations. A main high pressure fluid distribution line may include a steel pipe for conveying a high-pressure fracturing fluid. The fluid delivery system also includes a plurality of modular valve assemblies fluidly coupling a plurality of fluid sources to said main high pressure fluid distribution line. The system also includes each of said plurality of modular valve assemblies is mountable to said main high pressure fluid distribution line and each modular valve assembly may include a top connector, where said top connector on each of said modular valve assemblies receives a fluid conduit may include a steel pipe from one of said fluid sources at a user-selectable angle relative to a longitudinal axis of said main high pressure fluid distribution line, where said user- selectable angle may include orthogonal and non-orthogonal angles, thereby allowing for a flexible equipment layout on a well pad.

[0024] Implementations may include one or more of the following features: the fluid delivery system where each of said modular valve assemblies may include a vertically oriented gate valve stack defining a vertical flow path. Each modular valve assembly further may include a bleed-off circuit fluidly coupled to a location between a first isolation valve and a second isolation valve, said bleed-off circuit including a bleed valve. Said first isolation valve and said second isolation valve are large-bore gate valves. Each of said plurality of fluid sources may include a pump cluster. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0025] One general aspect includes a fluid delivery system for continuous fracturing operations connecting a plurality of pump clusters directly to a steel zipper trunk line, said steel zipper trunk line being connected to a plurality of wellbores through a plurality of valves, a plurality of vertically oriented gate valve stacks, each of said plurality of vertically oriented gate valve stacks configured to be directly coupled to said steel zipper trunk line at a distinct connection point. The fluid delivery system also includes a plurality of supply fluid conduits, each of said plurality of supply fluid conduits connecting one of said pump clusters to a corresponding one of said plurality of vertically oriented gate valve stacks. The system also includes where the fluid delivery system facilitates fluid delivery from the pump clusters to a plurality of wellheads via said steel zipper trunk line without an intermediary missile line.

[0026] Implementations may include one or more of the following features: the fluid delivery system where said plurality of valves may include a respective vertically oriented gate valve stack connected to said steel zipper trunk line to supply frac fluid for each of said plurality of wellbores, an upper horizontally oriented pipe mounted to a top of each respective vertically oriented gate valve stack that leads to a corresponding of said plurality of wellbores. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0027] For use in controlling frac operations a system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, hydraulics or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0029] FIG. 1 is a perspective view of an embodiment of the fluid delivery system, showing four vertically oriented gate valve stacks connected to a missile line.

[0030] FIG. 2 is a perspective view of another embodiment of the fluid delivery system, illustrating the angular flexibility of the steel pipes in the legs of the frac fluid feed lines relative to the axis of the missile line.

[0031] FIG. 3 is a top-down plan view of the embodiment shown in FIG. 2.

[0032] FIG. 4 is a perspective view of an embodiment of the system, wherein the vertical valve stacks are connected directly to a zipper trunk line, thereby replacing the missile line.

[0033] FIG. 5 is a top-down plan view of the embodiment shown in FIG. 4.

[0034] FIG. 6 is a perspective view of an alternative configuration of the embodiment connected directly to a zipper trunk line.

[0035] FIG. 7 is a top-down plan view of the embodiment shown in FIG. 6.

[0036] FIG. 8 is an elevational cross-sectional internal view of a gate valve that may be used as an upper or lower isolation valve in the vertical valve stacks.DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention provides a system and method for an improved fluid delivery interface between high-horsepower pumping units and a main fluid distribution line for hydraulic fracturing operations. The system, referred to herein as a vertical continuous stimulation system, is scalable and may be configured with two or more fluid inlet paths to meet the horsepower requirements of a given operation. A first innovation lies in the vertical orientation of the isolation valve assemblies, which confers significant advantages in reliability, operational flexibility, and cost-effectiveness over conventional, horizontally-oriented systems.

[0038] The system is referred to as "modular" for several key reasons related to its flexibility and design:

[0039] Adaptable Layout: The system is not fixed to a rigid layout. Its components, specifically the legs supplying frac fluid to the vertical valve stacks, can be arranged to connect to pump conduits at various orthogonal and non-orthogonal angles (acute, obtuse, or right angles). This adaptability allows the system to fit onto congested well pads with physical constraints.

[0040] Scalability: The design is scalable and not limited to a specific number of connections. It can be configured with two, four, six, or more vertical valve stacks (which may also be referred to herein more generally as modular valve assemblies) depending on the horsepower requirements of a given operation.

[0041] Interchangeable Use Cases: The system can be deployed in different configurations depending on the need. It can be used to improve an existing setup by connecting to a traditional missile line, or it can be used in a different configuration to replace the missile entirely by connecting directly to the zipper trunk line.

[0042] Embodiment 10A (FIG. 1) Referring to FIG. 1, a first embodiment of the system, designated 10A, is shown for use with a conventional missile line 51. The missile line 51 is a large-bore, typically rigid conduit that serves as the main fluid distribution line. It is configured to receive high-pressure fracturing fluid from a plurality of sources and direct it toward a connection point 120, which in turn leads to a zipper manifold and ultimately to one or more wellheads. For example, flex hose 66 that contains the total frac fluid flow from all sources might connect to the end of zipper line 280 in FIG. 7 whereby the other sources of frac fluid shown in FIG. 7 may or may not be present or in use. Continuing to look at the zipper line 280 in FIG. 7, it will be appreciated that the frac- directing valve stacks thereon can be used to relatively quickly and selectively direct frac fluid to any of six wells connected by pipes and valve stacks to the zipper lines.

[0043] The FIG. 1 embodiment 10A configuration utilizes four orthogonally oriented rigid steel pipe legs with respect to missile 51 that act as supply fluid conduits to supply frac fluid to the missile. In this case, the legs are connected at right angles to the missile. High-pressure fluid is supplied by pump clusters 12, 14, 16, and 18 and travels through respective steel pipe legs 13, 15, 17, and 19. The rigid legs are coupled preferably to and include steel rigid curved pipes 24, 25, 27, 29 that might also be flex pipe which lead to connectors 26, 28, 46, 56 at the top of each valve stack. Each valve stack includes at least a top gate valve (upper isolation valve), such as valves 30, 32, 48, and 58, and a lower gate valve (lower isolation valve), such as valves 36, 38, 52, 62. The stacks connect to and feed a central missile 51. A connector 33, 34, 50, or 60 in each valve stack is positioned between the upper and lower gate valves and also connects to the main bleed-off line 44. A three inch valve 35 (for example in valve stack 95) leads through line 37 to line 44.

[0044] The main bleed-off line 44 routes pressure to a bleed-off assembly 42 for safe depressurization.

[0045] The vertical gate valve stacks 80, 85, 90, 95 are an inventive feature of the system 10A. Each stack is a vertically oriented assembly of gate valves and connectors. Each stack comprises multiple connectors that can connect pipes to multiple sides, a lower isolation valve, and an upper isolation valve. The valves are preferably large-bore gate valves arranged in series along a vertical axis, creating a continuous vertical flow path for the fluid. These valves are preferably of a robust, greaseless design with enhanced sealing elements, capable of withstanding the highly abrasive and high-pressure environment of fracturing operations. US Patent No 11,435,001 discloses an exemplary embodiment of a suitable gate valve and is incorporated herein by reference.

[0046] This vertical orientation of the gate valves is a departure from the prior art. By orienting the flow path vertically, the system utilizes gravitational forces to assist in keeping the valve internals clear of proppant. During operation, the flow of fluid naturally carries sand and debris through the valves. In any instance of flow reduction or stoppage, gravity encourages any settling proppant to fall back down and out of the valve bodies, rather than accumulating in critical sealing areas as occurs in horizontal valves. This design feature significantly reduces abrasive wear, extends the operational life of the valves, and improves the reliability of the entire system.

[0047] Referring to FIG. 8, which shows a type of gate valve 800 that could be utilized with the invention. The gate valves shows a passageway 802 through the gate valve. By vertical orientation of the gate valves, it is meant that the passageway 802 of each gate valve is oriented vertically to obtain the reliability and operational life advantages discussed above.

[0048] Vertical valve stacks 80, 85, 90, 95 are each connected to the high pressure missile 51 by bottommost connector blocks 39, 40, 54, 64. Lower isolation valves 36, 38, 52, 60 are connected to a middle connector block, such as blocks 33, 60 that supports the bleed off circuits. Upper isolation valves 30, 32, 56, and 48 connect to the middle connector blocks and to an upper or top connector block such as connectors 26, 28, 46, and 56. The top connectors are positioned above the upper isolation valve and connect to rigid legs 13, 15, 17 and 19.

[0049] In this case, the missile 51 connects to the zipper line (not shown in FIG. 1) via flexible hose 66 and connector 68.

[0050] Embodiment 10B (FIGS. 2 and 3) Referring now to FIGS. 2 and 3, an alternative missile-based configuration, designated 10B, is shown. This embodiment highlights the system's angular flexibility. Pressurized frac fluid is supplied by pump clusters 102, 104, 106, and 108. The fluid travels through rigid steel pipe legs 158, 160, 162, and 164, which may be non-orthogonally oriented with respect to the missile 122. There is a wide range of angles to which the rigid legs can be safely connected to the missile. Essentially the legs can be oriented 360 degrees around each vertical valve stack in many different positions and to any range within this span. It will be appreciated that the mounting flanges with multiple fastener holes will permit this arrangement due to the vertical orientation of the valve stacks and the ease which the flanges can be connected in many different orientations.

[0051] As shown perhaps more clearly in the top view such as FIG. 3, 5 and 7, it will be appreciated that the legs that supply fluid are essentially straight, comprise rigid steel pipes, and revolve around the top connection to the vertical valve stacks.

[0052] The multi-angled connection of leg pipes to curved lines 126, 128, 130, and 132 is made via connectors with support stands 114, 116, 118, and 120. The curved pipe lines lead to the top connectors, such as top connector 134 on stack 150, of the vertically oriented missile feed gate valve stacks 150, 152, 154, and 156.

[0053] The valve stacks feed the high-pressure frac fluid into the missile 122, which in turn delivers it to the zipper or well, shown schematically as 124. Each valve stack is connected to a main bleed-off line 110 which is part of a bleed-off system 115 that safely vents pressure via pipe 112 to a mud pit or container.

[0054] Accordingly, the design of the connector and its connection to the fluid conduit through the gate valve stack allows the rigid conduit legs to be oriented at a wide range of user-selectable angles relative to the longitudinal axis of the missile line 122. Unlike conventional systems limited to 45 or 90-degree angles, the present invention allows the fluid conduits 158, 160, 162, 164 to be positioned at various acute, obtuse, or right angles as needed to accommodate the specific layout of the well pad. This angular flexibility provides operators with the ability to create more compact, efficient, and safer equipment layouts, working around existing wells or other obstacles without resorting to long, cumbersome, and failure-prone flex hoses.

[0055] Referring to FIG. 2, as shown in vertical gate valve stack 150, each vertical gate valve stack further includes a bleed-off circuit 138 that include a connector block, bleed off valve 139 and bleed off conduit 141 leading to bleed off manifold 110 and bleed off skid 115 that discharges to line 112 that may lead to a mud pit or other collection device. This circuit comprises conduit 141 that branches off from the main vertical path at a point between the lower isolation valve 140 and the upper isolation valve 136.

[0056] If desired, this arrangement allows for the safe depressurization of the vertical gate valve stack 150 and the pump cluster 102 after they have been isolated from the high-pressure missile line 122 by the closure of valves 136 and 140. The stacks may also be equipped with auxiliary ports for the installation of monitoring equipment, such as pressure transducers, or safety devices like pressure relief valves, depending on operational requirements.

[0057] Missile 122 is connected to the zipper and corresponding wellbores 124 via flexible line 117.

[0058] It will be appreciated that controls, computers, hydraulic lines to hydraulically operate valves and so forth are present but not shown for clarity.

[0059] Referring now to FIGS. 4-7, a second and particularly advantageous embodiment of the invention is shown. This embodiment realizes the goal of completely replacing the traditional missile line, thereby achieving significant cost savings and system simplification.

[0060] Embodiment 10C (FIGS. 4 and 5) Referring to FIGS. 4 and 5, a "Mipper Missile replacement" embodiment, designated 10C, is shown. The Mipper is the name given to this pipeline configuration because it combines benefits of the high pressure missile line and zipper line into one configuration. This configuration eliminates the missile by connecting the feed stacks discussed previously directly to the zipper line.

[0061] In this example, the system utilizes five legs fed by pump clusters 202, 204, 206, 208, and 210. Fluid flows through rigid steel legs 220, 222, 224, 225, and 226 through connectors such as connectors 212, 214, 216, 218. The connectors connect with curved pipes 228, 230, 232, 234, and 235 that lead to the top connectors on the vertical gate valve zipper feed stacks 280, 284, 290, 294 and 296. These feed stacks are mounted directly on the zipper line 200 and control the flow of frac fluid into it.

[0062] The zipper trunk line 200 is the main manifold that distributes fracturing fluid to a series of individual wells. As in the first embodiment, each vertical valve stack receives high-pressure fluid from a pump cluster (e.g., 202) via a fluid conduit (e.g., 220).

[0063] The zipper line itself is assembled with zipper line outlet valve stacks 282, 286, 292, and 298 that control flow from the zipper line to the individual wellbore valve stacks 268, 270, 272, and 274. A zipper line outlet valve stack, such as stack 282, is comprised of a bottom connector 252 for the zipper line, a bottom gate valve 250, and a top gate valve 248. This vertical zipper outlet stack 282 then connects via an upper horizontal pipe or "dog bone" to the final wellbore valve stack or Christmas tree 268. Horizontal pipe 254 illustrates such a connection between vertical zipper outlet stack 286 and individual wellbore valve stacks 270.

[0064] Each vertical input valve stack comprises a lower isolation valve, an upper isolation valve, and a bleed-off circuit with a bleed valve and bleed-off line. The principle of operation is identical to previously discussed vertical input valve stacks: the vertical orientation of the lower isolation and upper isolation valves prevents sand accumulation, and the dual-valve arrangement provides a secure method for isolating the associated pump cluster for maintenance while continuous pumping proceeds through the other stacks. The angular flexibility for connecting the fluid conduits is also retained, allowing for adaptable layouts even in the immediate vicinity of the wellheads.

[0065] By integrating the isolation and control functions directly onto the zipper line, this embodiment eliminates the need for the separate, large, and expensive missile. This reduces the monthly equipment rental cost (cited at $90,000 / month) to zero, shortens the overall length of the high-pressure piping, reduces the number of high-pressure connections (a primary source of leaks and safety risks), and further shrinks the required operational footprint on the well pad. FIGS. 6 and 7 show an alternative arrangement of this embodiment with different spacing and component layout, illustrating the modularity and adaptability of the design.

[0066] This embodiment eliminates the separate missile, saving significant rental costs, shortening the high-pressure piping, reducing connections, and shrinking the operational footprint.

[0067] Embodiment 10D (FIGS. 6 and 7) Referring to FIGS. 6 and 7, another missile replacement embodiment, designated 10D, is shown. This version uses four orthogonal legs to feed a zipper line connected to six wells. Pump clusters 300, 302, 304, and 306 are fluid sources that supply feed frac fluid through rigid pipe legs 301, 303, 305, and 307. The fluid then flows through curved pipes to the respective tops of gate valve zipper feed stacks 328, 334, 340, and 346, which are mounted onto the zipper line with suitable connectors. A representative zipper feed stack, 346, consists of a lower gate valve 348, a connector 350 with a bleed off assembly, an upper gate valve 352, and an upper connector 354 that connects to leg 301 fed by pump cluster 300.

[0068] The zipper line distributes as desired and controlled by valves the frac fluid to six wellbores via their respective wellbore stacks or Christmas trees 316, 318, 320, 322, 324, and 326. The connection is made through zipper line outlet valve stacks (e.g., 342) and a dog bone pipe 356. A representative zipper line valve stack, 342, includes an upper gate valve 358 and a lower gate valve 360.

[0069] Representative Gate Valve (FIG. 8) Referring to FIG. 8, a representative gate valve 800 suitable for use in any of the feed stacks or wellbore stacks is shown. The valve is designed to be installed such that its main passageway 802 is oriented vertically. A gate 804 moves perpendicularly to this vertical passageway to open or close the valve. The gate is moved by an operator shaft 806, which can be connected to a manual or hydraulic actuator. Flanges 808 and 810 are used for connecting the gate valve intoMethod of Operation

[0070] The system of the present invention enables a method for continuous fluid delivery during a hydraulic fracturing operation, allowing for pump maintenance without shutting down the entire job. The procedure is described below with reference to the components of embodiment 10B (FIGS. 2-3), though the principles apply equally to all embodiments.Procedure for Taking a Pump Cluster Offline

[0071] Reduce Pump Rate: The rate of the pump cluster to be serviced (e.g., pump cluster 102) is gradually reduced to zero. If possible, the lines may be flushed with clean fluid to minimize proppant in the system.

[0072] Primary Isolation: The lower isolation valve, such as valve 140, within the corresponding vertical feed gate valve stack (e.g., stack 150) is closed. This action isolates the pump cluster from the live, high-pressure missile 122.

[0073] Bleed Down Pressure: The bleed-off system 115 is utilized by opening the bleed valves e.g. in bleed off assembly 139, connected to the main bleed-off line 110. This allows trapped pressure in the fluid line to be safely vented through outlet pipe 112.

[0074] Secondary Isolation: Once pressure is confirmed at zero, the upper isolation valve e.g. 136 within the vertical feed gate valve stack 150 is closed. This establishes a dual-barrier pressure isolation which is a critical safety feature and industry standard, ensuring the line is de-energized for maintenance.

[0075] Continuous Pumping: Throughout this procedure, the other pump clusters 104, 106, and 108 remain operational, continuously pumping fracturing fluid through their respective valve stacks into the missile 122 through their respective valve stacks into the missile and down the well. This minimizes non-productive time and maintains the efficiency of the fracturing operation.Procedure for Bringing a Pump Cluster Back Online

[0076] Prepare System: After maintenance is complete, the bleed valves connected to the bleed-off system 115 are closed.

[0077] Prime Pumps: The pumps in cluster 102 are primed to fill their corresponding fluid lines with fluid and remove any air from the line.

[0078] Equalize Pressure: Pressure is equalized across the isolation valves within stack 150.

[0079] Open Isolation Valves: The isolation valves are opened to reconnect the fluid path to the missile 122, typically with the upper valve opened first, followed by the lower valve.

[0080] Resume Pumping: The pumps in cluster 102 are brought back online to rejoin the continuous pumping operation.

[0081] This method, enabled by the unique structure of the vertical valve stacks, provides a safe, efficient, and reliable means of managing high-horsepower pumping assets during a fracturing job, directly contributing to the overall effectiveness and economic viability of the well stimulation process.

[0082] The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and it will be appreciated by those skilled in the art that various changes in the size, shape and materials as well as in the details of the illustrated construction or combinations of features of the various elements may be made without departing from the spirit of the invention. Moreover, the scope of this patent is not limited to its literal terms but instead embraces all equivalents to the claims described.

Claims

1. A fluid delivery system for hydraulic fracturing operations, comprising: a main fluid distribution line comprising a high pressure steel pipe for conveying a high-pressure fracturing fluid;a plurality of fluid inlet paths fluidly coupled to the main fluid distribution line, each fluid inlet path configured to receive the high-pressure fracturing fluid from a fluid source;wherein each of said plurality of fluid inlet paths comprises a vertically oriented gate valve stack, each said vertically oriented gate valve stack defining a vertical flow path and comprising a first vertical flow path through a first isolation gate valve and a second vertical flow path through a second isolation gate valve; andsaid first isolation gate valve and said second isolation gate valve being arranged in series along said vertical flow path wherein a first gate in said first isolation gate valve and a second gate in said second isolation gate valve move orthogonally to said vertical flow path.

2. A fluid delivery system for hydraulic fracturing operations, comprising: a main high pressure fluid distribution line comprising a steel pipe for conveying a high-pressure fracturing fluid;a plurality of modular valve assemblies fluidly coupling a plurality of fluid sources to said main high pressure fluid distribution line;each of said plurality of modular valve assemblies is mountable to said main high pressure fluid distribution line and each modular valve assembly comprises a top connector, wherein said top connector on each of said modular valve assemblies receives a fluid conduit comprising a steel pipe from one of said fluid sources at a user-selectable angle relative to a longitudinal axis of said main high pressure fluid distribution line; andwherein said user- selectable angle comprises orthogonal and non-orthogonal angles, thereby allowing for a flexible equipment layout on a well pad.

3. A fluid delivery system for continuous fracturing operations connecting a plurality of pump clusters directly to a steel zipper trunk line, said steel zipper trunk line being connected to a plurality of wellbores through a plurality of valves, comprising: a plurality of vertically oriented gate valve stacks, each of said plurality of vertically oriented gate valve stacks configured to be directly coupled to said steel zipper trunk line at a connection point;a plurality of supply fluid conduits, each of said plurality of supply fluid conduits connecting one of said pump clusters to a corresponding one of said plurality of vertically oriented gate valve stacks; andwherein the fluid delivery system facilitates fluid delivery from the pump clusters to a plurality of wellheads via said steel zipper trunk line without an intermediary missile line.

4. The fluid delivery system of claim 1, wherein each of said plurality of fluid inlet paths further comprises a fluid conduit connecting the fluid source to a top of said vertically oriented gate valve stack, and wherein said fluid conduit is selectively connectable to said top at a plurality of different angles, said plurality of different angles including non-orthogonal angles.

5. The fluid delivery system of claim 1, wherein each said vertically oriented gate valve stack further comprises a bleed-off circuit fluidly coupled to the vertical flow path at a location between the first isolation gate valve and the second isolation gate valve, said bleed-off circuit including a bleed valve.

6. The fluid delivery system of claim 1, wherein the main fluid distribution line is a missile line configured to supply the high-pressure fracturing fluid to a zipper manifold.

7. The fluid delivery system of claim 1, wherein the main fluid distribution line is a zipper trunk line configured to supply the high-pressure fracturing fluid directly to a plurality of wellheads.

8. The fluid delivery system of claim 1, wherein said first isolation gate valve and second isolation gate valve are large-bore gate valves.

9. The fluid delivery system of claim 2, wherein each of said modular valve assemblies comprises a vertically oriented gate valve stack defining a vertical flow path.

10. The fluid delivery system of claim 2, wherein each modular valve assembly further comprises a bleed-off circuit fluidly coupled to a location between a first isolation valve and a second isolation valve, said bleed-off circuit including a bleed valve.

11. The fluid delivery system claim 10, wherein said first isolation valve and said second isolation valve are large-bore gate valves.

12. The fluid delivery system of claim 2, wherein each of said plurality of fluid sources comprise a pump cluster.

13. The fluid delivery system of claim 3, wherein said plurality of valves comprise a respective vertically oriented gate valve stack connected to said steel zipper trunk line to supply frac fluid for each of said plurality of wellbores, an upper horizontally oriented pipe mounted to a top of each respective vertically oriented gate valve stack that leads to a corresponding said plurality of wellbores.

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