(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2014/0352968 A1
`Pitcher et al.
`(43) Pub. Date:
`Dec. 4, 2014
`
`US 20140352968A1
`
`(54) MULTI-WELL SIMULTANEOUS
`FRACTURING SYSTEM
`
`(71) Applicant: Cameron International Corporation,
`Houston, TX (US)
`(72) Inventors: Jason L. Pitcher, The Woodlands, TX
`(US); Edward L. Ganzinotti, III,
`Houston, TX (US); Jay P. Painter,
`Webster, TX (US)
`
`(21) Appl. No.: 13/908,869
`(22) Filed:
`Jun. 3, 2013
`Publication Classification
`
`(51) Int. Cl.
`E2IB 43/12
`
`(2006.01)
`
`
`
`(52) U.S. Cl.
`CPC ...................................... E2IB 43/12 (2013.01)
`USPC .......................................... 166/308.1: 166/67
`
`(57)
`
`ABSTRACT
`
`A system for simultaneously fracturing multiple wells is pro
`vided. In one embodiment, the system includes fracturing
`trees installed at multiple wells. A fracturing manifold is
`connected to the fracturing trees and includes output valves to
`independently control flow of fracturing fluid from the mani
`fold to each of multiple wells. The system may also include a
`controller connected to the output valves so that the controller
`can remotely operate the output valves to simultaneously
`fracture the multiple wells and independently control the
`volume of fracturing fluid entering each of the wells from the
`fracturing manifold. Additional systems, devices, and meth
`ods are also disclosed.
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`PROCESSOR
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`MEMORY
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`INSTRUCTIONS
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`I/O INTERFACE
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`I/O DEVICES
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`F.G. 6
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`US 2014/0352968 A1
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`Dec. 4, 2014
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`MULT-WELL SIMULTANEOUS
`FRACTURING SYSTEM
`
`BACKGROUND
`0001. This section is intended to introduce the reader to
`various aspects of art that may be related to various aspects of
`the presently described embodiments. This discussion is
`believed to be helpful in providing the reader with back
`ground information to facilitate a better understanding of the
`various aspects of the present embodiments. Accordingly, it
`should be understood that these statements are to be read in
`this light, and not as admissions of prior art.
`0002. In order to meet consumer and industrial demand for
`natural resources, companies often invest significant amounts
`of time and money in finding and extracting oil, natural gas,
`and other Subterranean resources. Particularly, once a desired
`Subterranean resource is discovered, drilling and production
`systems are often employed to access and extract the
`resource. These systems may be located onshore or offshore
`depending on the location of a desired resource. Further, Such
`systems generally include a wellhead assembly through
`which the resource is extracted. These wellhead assemblies
`may include a wide variety of components, such as various
`casings, valves, fluid conduits, and the like, that control drill
`ing or extraction operations.
`0003. Additionally, such wellhead assemblies may use a
`fracturing tree and other components to facilitate a fracturing
`process and stimulate production from a well. As will be
`appreciated, resources such as oil and natural gas are gener
`ally extracted from fissures or other cavities formed in various
`Subterranean rock formations or strata. To facilitate extraction
`of Such resources, a well may be subjected to a fracturing
`process that creates one or more man-made fractures in a rock
`formation. This facilitates, for example, coupling of pre-ex
`isting fissures and cavities, allowing oil, gas, or the like to
`flow into the wellbore. Such fracturing processes typically
`include injecting a fracturing fluid-often a mixture or slurry
`including sand and water into the well to increase the well's
`pressure and form the man-made fractures.
`
`SUMMARY
`0004 Certain aspects of some embodiments disclosed
`herein are set forth below. It should be understood that these
`aspects are presented merely to provide the reader with a brief
`Summary of certain forms the invention might take and that
`these aspects are not intended to limit the scope of the inven
`tion. Indeed, the invention may encompass a variety of
`aspects that may not be set forth below.
`0005 Embodiments of the present disclosure generally
`relate to simultaneous fracturing of multiple wells. In at least
`Some instances, pumping fluid into two or more wells simul
`taneously to fracture those wells reduces total pumping time
`for fracturing wells at a pad site. In one embodiment, a frac
`turing system includes a manifold having valves to indepen
`dently control flow rates of fracturing fluid to multiple wells.
`Fracturing fluid can be pumped through the manifold and into
`the multiple wells simultaneously, and the valves can be
`operated to balance the volume of fluid pumped into each
`well. A controller can also be used with the system to
`remotely actuate the manifold valves and control flow rates
`based on measured parameters and stored data.
`0006 Various refinements of the features noted above may
`exist in relation to various aspects of the present embodi
`
`ments. Further features may also be incorporated in these
`various aspects as well. These refinements and additional
`features may exist individually or in any combination. For
`instance, various features discussed below in relation to one
`or more of the illustrated embodiments may be incorporated
`into any of the above-described aspects of the present disclo
`Sure alone or in any combination. Again, the brief Summary
`presented above is intended only to familiarize the reader
`with certain aspects and contexts of some embodiments with
`out limitation to the claimed Subject matter.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0007. These and other features, aspects, and advantages of
`certain embodiments will become better understood when the
`following detailed description is read with reference to the
`accompanying drawings in which like characters represent
`like parts throughout the drawings, wherein:
`0008 FIG. 1 generally depicts a fracturing system for
`simultaneously fracturing multiple wells in accordance with
`one embodiment of the present disclosure;
`0009 FIG. 2 is a block diagram of various components of
`the fracturing system of FIG. 1 in accordance with one
`embodiment;
`0010 FIGS.3 and 4 are flow charts representative of meth
`ods for simultaneously fracturing multiple wells in accor
`dance with certain embodiments of the present disclosure;
`0011 FIG.5 generally depicts two horizontal wells having
`fracturing Zones in accordance with one embodiment;
`0012 FIG. 6 is a block diagram of a programmable con
`troller for operating the fracturing system of FIGS. 1 and 2 in
`accordance with one embodiment; and
`0013 FIGS. 7-10 depict various fracturing manifolds in
`accordance with certain embodiments of the present disclo
`SUC.
`
`DETAILED DESCRIPTION OF SPECIFIC
`EMBODIMENTS
`0014. One or more specific embodiments of the present
`disclosure will be described below. In an effort to provide a
`concise description of these embodiments, all features of an
`actual implementation may not be described in the specifica
`tion. It should be appreciated that in the development of any
`Such actual implementation, as in any engineering or design
`project, numerous implementation-specific decisions must be
`made to achieve the developers specific goals, such as com
`pliance with system-related and business-related constraints,
`which may vary from one implementation to another. More
`over, it should be appreciated that such a development effort
`might be complex and time consuming, but would neverthe
`less be a routine undertaking of design, fabrication, and
`manufacture for those of ordinary skill having the benefit of
`this disclosure.
`0015. When introducing elements of various embodi
`ments, the articles “a,” “an,” “the and “said are intended to
`mean that there are one or more of the elements. The terms
`“comprising.” “including,” and “having” are intended to be
`inclusive and mean that there may be additional elements
`other than the listed elements. Moreover, any use of “top.”
`“bottom,” “above,” “below, other directional terms, and
`variations of these terms is made for convenience, but does
`not require any particular orientation of the components.
`0016 Turning now to the present figures, an example of a
`fracturing system 10 is provided in FIG. 1 in accordance with
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`one embodiment. The fracturing system 10 facilitates extrac
`tion of natural resources (e.g., oil or natural gas) fromwells 12
`and 14. Particularly, by injecting a fracturing fluid into the
`wells 12 and 14, the fracturing system 10 increases the num
`ber or size of fractures in a formation 16 to enhance recovery
`of natural resources present in the formation 16.
`0017. The fracturing fluid may, for example, include water
`(or another liquid) mixed with sand or some other proppants.
`The fracturing fluid is pumped into the formation 16 to extend
`fractures and fill them with the proppants, which operate to
`hold open the fractures after pumping has stopped to allow
`formation fluids to be more easily produced via the wells 12
`and 14. In at least Some embodiments, fracturing fluids used
`in the wells 12 and 14 also include other additives. For
`example, the fracturing fluid can include polymers or other
`agents to increase the viscosity of the fracturing fluid (which
`aids in carrying the proppants down the wells). And in some
`instances, the fracturing fluid includes acid (e.g., hydrochlo
`ric acid) that initiates fissures in the formation 16.
`0018. Although generally depicted as horizontal wells
`extending through the formation 16, the wells 12 and 14 could
`take other forms (e.g., vertical wells). In the presently illus
`trated embodiment, the wells 12 and 14 are surface wells
`formed at a common pad 20 and accessed through wellhead
`assemblies 18 installed at the wells. It will, of course, be
`appreciated that natural resources can be extracted from other
`types of wells, such as platform or Subsea wells.
`0019. The fracturing system 10 also includes a fracturing
`supply system 22 coupled to the wellhead assemblies 18 by
`conduits 24 and 26 so as to provide fracturing fluid to the
`wells 12 and 14 via the conduits. In one embodiment, the
`fracturing Supply system 22 includes various components
`depicted in block diagram 30 of FIG. 2. As here illustrated,
`each of the wells 12 and 14 has a fracturing tree 32 (part of the
`wellhead assembly 18 of FIG. 1) installed on a wellhead 34.
`The fracturing trees 32 include valves to control flow of
`fracturing fluids through the wellheads 34 and into their
`respective wells. The wells 12 and 14 include sliding sleeves
`38, which can be run into or as part of casing strings in the
`wells. When actuated, the sliding sleeves 38 move to expose
`ports in the casing strings, allowing fracturing fluid pumped
`down the wells 12 and 14 to reach the formation 16 via the
`ports. The wells 12 and 14 can be divided into multiple
`fracturing Zones (also referred to as fracturing stages) and
`sliding sleeves 38 can be used to isolate the fracturing Zones
`to allow sequential fracturing of each Zone.
`0020. In at least some embodiments, such as that depicted
`in FIG. 2, the sliding sleeves 38 are ball-actuated sliding
`sleeves and the fracturing system includes one or more ball
`launchers 40 to drop balls 42 (which may also be referred to
`as packer balls or frac balls) into the wells 12 and 14. For
`instance, at least Some of the sliding sleeves 38 are con
`structed with seats or baffles for receiving packer balls 42.
`When the packer ball engages the seat, the ball inhibits flow
`through the seat and fluid pressure (e.g., from the pumping of
`fluid down a well behind the ball) increases and causes the
`ball to push the sliding sleeve 38 open. The sliding sleeve 38
`can be retained in place by a shearpin or some other device so
`the ball does not move the sleeve 38 until the pressure on the
`ball exceeds a threshold amount.
`0021. The various sliding sleeves 38 of each well can be
`constructed for actuation by differently sized packer balls 42
`and generally have seats with apertures that allow Smaller
`balls 42 to pass through without actuating the sleeve. More
`
`specifically, the sliding sleeves 38 can be arranged in the wells
`in sequence by the size of the balls 42 used to actuate the
`sleeves, with the sleeves operated by the smallest balls pro
`vided furthest from the surface and the sleeves operated by the
`largest balls provided closest to the Surface. In this arrange
`ment, the Smallest ball can dropped into a well and pass
`through the apertures in other sleeves before reaching (and
`actuating) the sleeve furthest from the surface. Balls of
`increasing size can then be sequentially dropped to actuate
`additional sleeves in the well, with the largest ball being the
`last dropped in order to actuate the sleeve closest to the
`surface. The sliding sleeves 38 can be placed between adja
`cent fracturing Zones in the wells So that, as each ball 42
`engages the seat of a corresponding sliding sleeve 38, the ball
`inhibits flow through the seat and isolates the fracturing Zone
`associated with that actuated sleeve from other fracturing
`Zones further down the well. To facilitate the sequential actua
`tion of the sleeves 38, the conduits (e.g., conduits 24 and 26)
`connecting the ball launchers 40 to the wells 12 and 14 can be
`provided as single high-pressure lines (one to each well)
`having bores of sufficient size to allow the largest packer balls
`42 to pass from the ball launchers 40 to the wells.
`0022. The system depicted in FIG. 2 also includes a frac
`turing manifold 44 for controlling the flow of fracturing fluids
`to both well 12 and well 14. Fluid conduits 24 and 26 (FIG. 1)
`generally connect the fracturing manifold 44 to the wells 12
`and 14. This allows fluid to be routed from the manifold to
`either or both of the wells 12 and 14 via one or more manifold
`output valves 48. The output valves 48 can include any suit
`able valves (e.g., chokes orgate valves) that facilitate separate
`and independent control of the flow of fluid from the fractur
`ing manifold 44 to each of the wells 12 and 14. In some
`embodiments the ball launchers 40 are provided separately
`from the fracturing manifold 44 (as depicted in FIG. 2), while
`in others the ball launchers 40 are integrated into the manifold
`44 (see, e.g., FIGS. 7-10).
`0023 Various components, collectively denoted with ref
`erence numeral 46 in FIG. 2, cooperate to provide fracturing
`fluid to the manifold 44. In the depicted embodiment, such
`components include pumps 50, fluid tanks 52, and blenders
`54. The pumps 50 can be provided by pumping trucks or in
`Some other manner, and these pumps are used to route fluid
`from the fluid tanks 52 to the manifold 44 and, ultimately, to
`the wells. Though often water-based, any suitable fracturing
`fluids can be stored in the fluid tanks 52. In at least some
`embodiments, the fracturing fluid stored in the fluid tanks is
`gelled or crosslinked for increased viscosity, thereby enhanc
`ing the ability of the fluid to transport proppants to the for
`mation.
`0024. One or more blenders 54 are used to mix additives
`58 into the fracturing fluid. While some other embodiments
`include a single blender 54, the system depicted in FIG. 2
`includes two blenders. One of the blenders 54 can be used to
`mix an additive 58 of sand or some other proppant into the
`fracturing fluid routed from the fluid tanks 52 so that the
`proppants can be injected into the formation 16 to maintain
`fissures created or extended during fracturing. The other
`blender 54 can be used to mix an additive 58 of acid that
`initiates the creation of new fissures or the extension of old
`fissures in the formation 16. In some instances, the fracturing
`fluid with acid is provided for an initial period to promote
`fissures and then followed with proppant-laden fracturing
`fluid to inhibit closing of these fissures once fracturing is
`completed. Given its role in initiating fissures in the formation
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`16, the mix of fracturing fluid and acid can be referred to as a
`“fracturing spear.” As noted above, a single blender 54 could
`instead be used for mixing additives into the fracturing fluid.
`For example, a single blender 54 could add acid to the frac
`turing fluid for a given period, after which the blender 54
`could be converted to then add a proppant to the fracturing
`fluid for another time period. But having two blenders 54 may
`be more efficient in some instances by avoiding conversion of
`a single blender to mix different additives into the fracturing
`fluid at different times. And while two blenders 54 are pres
`ently depicted, it is noted that additional blenders 54 could
`also be provided.
`0025. In those embodiments having multiple blenders 54,
`and as illustrated in FIG. 2 by way of example, the manifold
`44 can include input valves 56 for controlling which fractur
`ing fluid is routed to the output valves 48 at a given time. For
`instance, one of the input valves 56 can be opened to allow the
`fracturing spear into the manifold 44 (that is, the fracturing
`fluid mixed with acid by one of the blenders), while another of
`the input valves 56 is closed to inhibit flow of proppant-laden
`fracturing fluid (mixed by a different blender) into the mani
`fold 44. Once a desired amount of spear fluid is received by
`the manifold 44 (which can be routed to one or both wells 12
`and 14), the input valves 56 can be operated to stop flow of the
`spear fluid into the manifold 44 and to allow the fracturing
`fluid with proppants to enter the manifold 44 and pass to the
`wells 12 and 14. Like the output valves 48, the input valves 56
`can include chokes, gate valves, or any other Suitable valves.
`0026. Although any or all of the ball launchers 40, the
`output manifold valves 48, and the input manifold valves 56
`could be actuated manually, in at least Some embodiments
`these components are operated remotely by a controller. In
`FIG. 2, for example, a controller 60 is connected to the ball
`launchers 40, the valves 48, and the valves 56 to control
`fracturing of the wells 12 and 14. More specifically, the con
`troller 60 can operate the valves 48 to independently control
`the flow of fracturing fluid to each of the wells 12 and 14 (e.g.,
`with a separate valve 48 for each of the wells). One or more
`sensors 62 (e.g., flow meters, pressure gauges, and densim
`eters) are connected downstream from the output valves 48 to
`measure operational parameters (e.g., flow rate and pressure).
`And as discussed in greater detail below, these measured
`parameters can then be provided as input to the controller 60
`to facilitate operation of the fracturing system. The controller
`60 can also operate the valves 56 to select a fracturing fluid to
`be provided to the wells (e.g., one with a high acid concen
`tration or one carrying proppants) and operate the ball launch
`ers 40 to drop balls into the wells 12 and 14 (e.g., to engage
`sliding sleeves 38 and select fracturing Zones). Still further,
`the controller 60 of some embodiments can also control
`operation of other devices, such as the blenders 54 and the
`pumps 50.
`0027. To reduce the amount of time needed to fracture
`wells on a shared pad, at least some embodiments of the
`present technique enable multiple wells to be fractured simul
`taneously. That is, fracturing fluid may be pumped into two or
`more wells at the same time to fracture rock Surrounding the
`wells and stimulate well productivity. This is in contrast to
`other techniques, such as sequential fracturing of each well or
`other fracturing processes (e.g., Zipper fracturing) in which
`two wells alternate between being prepared for fracturing and
`actually being fractured. The simultaneous fracturing tech
`niques disclosed herein can be used to reduce, in some
`instances significantly, the amount of pumping time and asso
`
`ciated costs for injecting fluid to fracture multiple wells com
`pared to Some previous approaches.
`0028. With this in mind, two processes for fracturing mul
`tiple wells (e.g., wells 12 and 14) are generally represented by
`flow charts 70 and 90 in FIGS. 3 and 4 in accordance with
`certain embodiments. These processes are described below in
`the context of the fracturing system and various components
`described above with respect to FIGS. 1 and 2, but it will be
`appreciated that the methods could be readily applied to other
`systems.
`0029. In the embodiment generally represented in FIG. 3,
`the wells 12 and 14 are connected to the fracturing manifold
`44 (block 72). The wells 12 and 14 can be connected in any
`Suitable manner, but in at least some instances each of the
`wells 12 and 14 are connected to the manifold 44 via a conduit
`with a bore diameter sufficient to pass any packer balls 42 to
`be dropped within the well (e.g., a conduit with a four-inch
`bore in one embodiment). Once the wells 12 and 14 are
`connected to the fracturing manifold, fracturing fluid can be
`pumped into the manifold (block 74) and then routed out of
`the manifold (block 76) into the wells 12 and 14 such that they
`receive fracturing fluid concurrently. Pumping of the fractur
`ing fluid into each of the wells continues so that the wells 12
`and 14 can be fractured simultaneously (block 78) to stimu
`late productivity of the wells. Post-fracturing production can
`commence (block 80) at any desired time after fracturing is
`complete (e.g., soon after flowback testing or after a pro
`longed shut-in period).
`0030 Fracturing multiple wells simultaneously reduces
`the amount of pumping time (and expense) needed to com
`plete fracturing of wells at a pad. In at least Some instances,
`operation of the fracturing system can be improved by con
`trolling the individual flows of fracturing fluid to each well
`from the fracturing manifold 44. By way of example, the
`process generally represented in FIG. 4 includes pumping
`fracturing fluid into multiple wells simultaneously (block92)
`and monitoring one or more fluid parameters for each well
`(block 94). Examples of the monitored fluid parameters
`include flow rate, flow Volume, density, and pressure, and
`these parameters can be measured via any suitable devices
`(e.g., sensors 62) downstream from the output valves 48. The
`method also includes operating valves of the fracturing mani
`fold 44 (e.g., output valves 46 and input valves 56) to control
`the fracturing fluid entering each of the wells connected to the
`manifold (block 96) based on fluid parameters monitored for
`each well. Additionally, in this embodiment the method
`includes dropping balls (block 98) in the wells 12 and 14 to
`actuate sliding sleeves 38 and isolate a selected fracturing
`stage from preceding stages deeper in the wells.
`0031. The operating of the valves and dropping of balls
`represented by blocks 96 and 98 may be better understood
`with reference to FIG.5. As here depicted, the wells 12 and 14
`have lateral (here horizontal) portions extending through the
`formation 16. The lateral portions of these wells can have
`lengths 102 and 112 of thousands offeet measured heel to toe,
`and these lengths may be equal to or different from one
`another. The lateral portions of the wells 12 and 14 can be
`divided into multiple fracturing Zones. In FIG. 5, the well 12
`includes fracturing Zones or stages 104, 106, 108, and 110.
`and the well 14 includes fracturing Zones or stages 114, 116,
`118, and 120. Although only a handful of fracturing Zones are
`depicted herein for the sake of explanation, it is noted that the
`wells 12 and 14 could include any number of desired fractur
`ing Zones. Further, each well could be divided into fracturing
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`Zones of equal size or of different size, and the Zones of the
`different wells could also be sized similarly or differently
`compared to one another. The fracturing Zones in some
`embodiments are divided by sliding sleeves 38 to facilitate
`sequential isolation and fracturing of these Zones.
`0032. In at least some embodiments, including the process
`represented in FIG. 4, the fluid distribution between the
`simultaneously fractured wells is controlled to reduce total
`pumping time for fracturing the wells. The amount of frac
`turing fluid used for each well (and for each fracturing Zone in
`the well) can vary depending on the characteristics of the well
`(e.g., length of well or porosity of the formation). But absent
`leaks in the system, fluid distribution from the fracturing
`manifold 44 can be described by:
`
`0033 in which V is the volume of fracturing fluid output
`from the fracturing manifold 44, n is the number of wells
`being simultaneously fractured (two in the presently
`described embodiment, although a different number of wells
`may be simultaneously fractured in other embodiments), and
`V is the volume of fracturing fluid pumped into an individual
`well i. Given the relationship of flow volume to flow rate, the
`fluid distribution from the manifold 44 is also described by:
`
`wherein Q, is the volumetric flow rate for well i.
`0034. In a simple case in which the wells 12 and 14 are
`identical in length, number of fracturing Zones, and wellbore
`length of the fracturing Zones, and also in which each frac
`turing Zone is to receive the same amount of fracturing fluid,
`the fracturing fluid in the manifold 44 could be divided evenly
`by the output valves 48 so that each well 12 and 14 receives
`fracturing fluid at the same rate. Such as twenty-five barrels
`(approximately 2980 liters) per minute, for an identical
`amount of time. More specifically, a desired amount of frac
`turing spear fluid (e.g., fifty barrels) can be provided to each
`well 12 and 14 simultaneously, Such as by opening an input
`valve 56 to allow the spear fluid to enter the manifold 44 and
`opening output valves 48 Such that equal amounts of the spear
`fluid enters each well. The input valves 56 can then be oper
`ated to stop flow of the spear fluid into the manifold and to
`permit flow of a proppant-laden fracturing fluid into the wells
`12 and 14 in equal amounts. Once a given Zone has been
`fractured, the next fracturing Zone can be selected by drop
`ping balls 42 into each of the wells to activate sliding sleeves
`38 and the spear fluid and the proppant-laden fluid can be
`routed in the same way to the next fracturing Zone. This may
`be repeated until all of the fracturing Zones have been frac
`tured.
`0035. But in practice there will typically be variation in
`one or more well or fracturing parameters (e.g., wells of
`different lengths or differences in fracturing Zones). In Such
`instances, fluid flow to the individual wells from the fractur
`ing manifold 44 can be controlled through operation of the
`output valves 48. For example, if the well 12 were longer than
`
`the well 14, pumping fracturing fluid at the same rate into
`each well to fracture the lowest Zones in each well (i.e., Zones
`104 and 114) and then dropping balls 42 into each well at the
`same time to select the next fracturing Zones (i.e., Zones 106
`and 116) for each well would cause a greater volume of
`fracturing fluid to be pumped into the fracturing Zone 104
`than into the fracturing Zone 114 (due to the increased volume
`of fracturing fluid in the well 12 compared to that in well 14
`when the balls 42 are dropped).
`0036. In some embodiments, however, the volumes of
`fracturing fluid pumped into Zones 104 and 114 are balanced
`by operating the output valves 48 to independently control
`flow to the wells and change the comparative flow rates of
`fracturing fluid into the wells 12 and 14. As noted above, the
`Volume of fracturing fluid pumped into each well is equal to
`the product of the volumetric flow rate and the amount of time
`the fluid flows at that rate. Thus, the volume of fracturing fluid
`pumped into each well can be controlled by adjusting either
`the flow rate or the amount of time that the fluid is pumped.
`The greater volume of the well 12 (due to its increased length)
`can be accounted for as an offset to the amount of fluid that is
`to be pumped into well 12 from the manifold 44 to fracture
`Zone 104 before dropping a ball 42 to select the next fractur
`ing Zone. For instance, if a casing string of the well 12 receiv
`ing the fracturing fluid has a Volume that is greater than that of
`a similar casing string of well 14, the manifold output valves
`48 can be operated to slow the flow (and reduce the volume)
`to the well 12 from the manifold 44 compared to the flow (and
`volume) to the well 14. Further, full flow (e.g., twenty-five
`barrels per minute) can be provided to the well 14 and a
`desired fracturing time for a given Zone can be calculated
`based on:
`
`the volume of fracturing fluid to pump into the
`where V,
`fracturing Zone, Q is the volumetric flow rate at which fluid is
`pumped into the well 14 from the fracturing manifold 44, t is
`the desired fracturing time for the zone, and V is the volume
`of the passageway (i.e., fluid conduit) from the ball launcher
`40 (of the well 14) to the far end of the Zone being fractured.
`0037 Accordingly, in one embodiment a manifold valve
`48 is opened to allow full flow of fracturing fluid, and the
`Volumetric flow rate is measured via a sensor 62 (e.g., a flow
`meter) and input to the controller 60. The desired fracturing
`volume is provided to the controller 60 as initial data, and the
`Volume of the passageway can also be provided as (or calcu
`lated from) initial data to the controller 60. Once the desired
`fracturing time is determined for Zone 114, that time can be
`input into the same formula to calculate the appropriate flow
`rate (the only remaining variable) from the manifold 44 to the
`well 12 while fracturing the Zone 104. (It is noted that the
`fracturing and passageway Volumes for Zone 104 can also be
`determined from initial data provided to the controller 60, but
`may differ from those for Zone 114.) The manifold valve 48
`that controls flow to the well 12 can then be adjusted to set the
`flow rate (which can be measured by a sensor 62) to the
`calculated amount. Once the desired fracturing time has
`elapsed, the ball launchers 40 may be activated to drop balls
`42 into the wells 12 and 14 to isolate the next fracturing stages
`for stimulation. Each fracturing stage of corresponding pairs
`of stages (e.g., Zones 106 and 116, Zones 108 and 118, and
`Zones 110 and 120) can be fractured at the same rate and for
`the same duration if desired, although the rates and durations
`
`IWS EXHIBIT 1021
`
`EX_1021_012
`
`

`

`US 2014/0352968 A1
`
`Dec. 4, 2014
`
`could also be varied (e.g., if it is intended that the Zones are to
`receive different volumes of fracturing fluid).
`0038 Although the above example describes balancing
`fluid distribution by slowing the flow rate into one well com
`pared to another, in other embodiments the flow rates of both
`wells may be kept the same while the fracturing time is varied.
`For example, rather than slowing the flow rate of fluid from
`the manifold 44 to the well 12 for fracturing Zone 104, the
`fracturing time could be reduced. That is, a valve 48 of the
`manifold could be closed once a desired volume of fracturing
`fluid has been pumped into the well 12 while additional
`fracturing fluid is pumped into well 14.
`0039 Various functionality described above (including,
`for example, determining desired flow rates and times for
`multiple wells