Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR PROVIDING PRESSURE FOR WELL
TREATMENT OPERATIONS
FIELD OF THE INVENTION
The present invention relates generally to well operations, and more
particularly to
methods and apparatuses for manufacturing well treatment fluid so as to
conserve labor,
infrastructure, and environmental impact.
BACKGROUND
In the production of oil and gas in the field, it is often required to
stimulate and treat
several well locations within a designated amount of time. Stimulation and
treatment
processes often involve mobile equipment that is set up and put in place at a
pad and then
moved by truck from pad to pad within short time periods. Only during non-
stimulation
activities, such as water flood operations, can some operations occur
simultaneously.
This movement of equipment and personnel can involve complex logistics. The
servicing and stimulation of wells can require a series of coordinated
operations that begin
with the supply by truck of equipment, supplies, fixel, and chemicals to the
wellhead. The
equipment is then set up and made ready with proppant and chemicals. After
completion of
the well services, equipment must be broken down and made ready for transport
to the next
pad for service. Often, the next pad will be less than 500 feet away from the
previously
treated pad. In addition, due to the limited storage capacity of the moving
equipment for
chemicals and equipment, additional trucks are often required to resupply and
reequip an
existing operation. This movement of equipment and supplies has environmental
impacts,
and the exposure of mobile equipment to adverse weather conditions can
jeopardize well
treatment operations and worlcer safety.
SUMMARY
In general, an apparatus for providing, pressure for a well fracturing
operation is
disclosed. The apparatus can include one or more docking areas for docking one
or more
pumping units to a pressure manifold wherein the one or more docking areas are
operable to
provide access between one or more pumping units, and a structure operable to
enclose
the one or more docking areas and pumping units. The apparatus can also
include a crane
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system, a central lubrication systein connected to the one or more pumping
units for
providing lubrication fluid to the one or more pumping units, and a central
power system
connected to the one or more pumping units for starting the one or more
pumping units. The
central power system can include a hydraulic power system. The apparatus can
include a
central cooling system connected to the one or more pumping uzzits for cooling
the one or
more puinping units. The central cooling system can include a cooling tower.
The at least
one of the one or more-doclcing areas can extend outside of the structure. The
apparatus can
include a ventilation systein. The apparatus can include a central fueling
system connected to
the one or more pumping units for supplying fuel to the one or more pumping
units. The
central fueling system supplies one or more fuels from the group consisting
of: diesel,
gasoline, natural gas, or electricity. The structure can include one or more
structures from the
group consisting of a supported fabric structure, a collapsible structure, a
prefabricated
structure, a retractable structure, a composite structure, a temporary
structure, a prefabricated
wall and roof structure, a deployable structure, a modular structure, a
preformed structure, a
mobile accommodation structure, and combinations thereof. The one or more
docking areas
can include walkways. The one or more docking areas can include one or
more.lubrication
connections, coolant connections, fuel connections, power connections, and
pressure
connections. The one or more pumping units can include heaters.
An apparatus for providing pressure for a well fracturing operation is
disclosed. The
apparatus can include one or more pumping units, a central fueling system
connected to the
one or more pumping units, a central power system connected to the one or more
pumping
units, a central lubrication system connected to the one or more pumping
units, and a central
cooling system connected to the one or more pumping units. The central power
system can
include a hydraulic power system. The central cooling system can include a
cooling tower.
The apparatus can include a ventilation system. The central fueling system
can. supply one or
more fuels from the group consisting of: diesel, gasoline, natural gas, or
electricity.
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A method for operating one or more pumping units for a well fracturing
operation
from a central land based location is disclosed. The method includes providing
fuel to the
one or more puinping units fiom the central location, providing lubrication to
the one or more
pumping units from the central location, providing power to the one or more
pumping units
from the central location, and providing coolant to the one or more pumping
units from the
central location. The power can be provided from a hydraulic power system. The
coolant
can be provided from a cooling tower. The method can include providing
ventilation to the
one or more pumping units. The fuel can include of one or more fuels from the
group
consisting of: diesel, gasoline, natural gas, or electricity. The method can
also include
enclosing the one or more pumping units in a structure.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present disclosure and advantages thereof
may
be acquired by referring to the following description taken in conjunction
with the
accompanying drawings. The drawings illustrate only exemplary embodiments and
are not
intended to be limiting against the invention.
Figure 1 is a diagram of a centralized well treatment facility.
Figure 2 is a flow diagram of a centralized well treatment facility.
Figure 3 is a flow diagram of central manifold used to treat wells and recover
production fluid.
Figure 4 is a diagram of a multiple manifold well treatment system.
Figure 5 is a schematic of a manifold apparatus for directing treatment fluid.
Figure 6 is a schematic of a manifold apparatus for directing treatment fluid.
Figure 7 is a schematic of a simultaneous fracturing method.
Figure 8 is an aerial view of the pumping grid apparatus.
Figure 9 is an aerial view of a structure that can enclose the pumping grid
apparatus.
Figure 10 is a side view of the pumping grid apparatus.
Figure 11 is an aerial view of the fracturing operations factory and a remote
pumping
grid apparatus.
Detailed Description
The details of the methods and apparatuses according to the present invention
will
now be described with reference to the accompanying drawings.
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In reference to Figure 1, in one embodiment, a well treatment operations
factory 100
includes one or more of tlie following: a centralized power unit 103; a
pumping grid 111; a
central manifold 107; a proppant storage system 106; a chemical storage system
112; and a
blending unit 105. In this and other embodirrients, the well treatment factory
may be set upon
a pad from which many other weliheads on other pads 110 may be serviced. The
well
treatment operations factory may be connected via the central manifold 107 to
at least a first
pad 101 containing one or more wellheads via a first connection 108 and at
least a second pad
102 containing one or more wellheads via a second connection 109. The
connection may be
a standard piping or tubing known to one of ordinary skill in the art. The
factory may be
open, or it may be enclosed at its location in various combinations of
structures including a
supported fabric structure, a collapsible structure, a prefabricated
structure, a retractable
structure, a composite structure, a temporary building, a prefabricated wall
and roof unit, a
deployable structure, a modular structure, a preformed structure, or a mobile
accommodation
unit. The factory may be circular and may incorporate alleyways for
maintenance access and
process fluid flow. The factory, and any or all of its components can be
climate controlled,
air ventilated and filtered, and/or heated. The heating can be accomplished
with radiators,
heat plumbing, natural gas heaters, electric heaters, diesel heaters, or other
kn.own equivalent
devices. The heating can be accomplished by convection, radiation, conduction,
or other
known equivalent methods.
In one einbodiment of the centralized power unit 103, the unit provides
electrical
power to all of the subunits within the well operations factory 100 via
electrical connections.
The centralized power unit 103 can be powered by liquid fuel, natural gas, or
other equivalent
fuel and may optionally be a cogeneration power unit. The unit may comprise a
single trailer
with subunits, each subunit with the ability to operate independently. The
unit may also be
operable to extend power to one or more outlying wellheads.
In one embodiment, the proppant storage system 106 is connected to the
blending unit
105 and includes automatic valves and a set of tanlcs that contain proppant.
Each tank can be
monitored for level, material weight, and the rate at wliich proppant is being
consumed. This
information can be transmitted to a controller or control area. Each tank is
capable of being -
filled pneumatically and can be emptied through a calibrated discharge chute
by gravity.
Gravity can be the substantial means of delivering proppant from the proppant
tank. The
tai-Acs may also be agitated in the event of clogging or unbalanced flow. The
proppant tanks
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can contain a controlled, calibrated orifice. Each tank's level, material
weight, and calibrated
orifice can be used to monitor and control the amount of desired proppant
delivered to the
blending unit. For instance, each tanlc's orifice can be adjusted to release
proppant at faster
or slower rates depending upon the needs of the formation and to adjust for
the flow rates
measured by the change in weight of the taizlc. Each proppant tank can contain
its own air
ventilation and filtering. In reference to Figure 8, the tanlcs 106 can be
arranged around each
blending unit 105 within the enclosure, with each tanlc's discharge chute 803
located above
the blending unit 105. The discharge chute can be connected to a surge hopper
804. In one
embodiment, proppant is released from the proppant storage unit 106 through a
controllable
gate in the unit. When the gate is open, proppant travels from the proppant
storage unit into
the discharge chute 803: The discharge chute releases the proppant into the
surge hopper. In
this embodiinent, the surge hopper contains a controlled, calibrated orifice
or aperture 807
that releases proppant froni the surge hopper at a desired rate. The aniount
of proppant in the
surge hopper is maintained at a substantially constant level. Each tank can be
connected to a
pneumatic refill line 805. The tanks' weight can be measured by a measurement
lattice 806
or by weight sensors or scales. The weight of the tanks can be used to
determine how much
proppant is being used during a well stimulation operation, how much total
proppant was
used at the completion of a well stimulation operation, and how much proppant
remains in
the storage unit at any given time. Tanks may be added to or removed from the
storage
system as needed. Empty storage tanks may be in the process of being filled by
proppant at
the same time full or partially full tanks are being used, allowing for
continuous operation.
The tanks can be arranged around a calibrated v-belt conveyor. In addition, a
resin-coated
proppant may be used by the addition of a mechanical proppant coating system.
The coating
system may be a Muller System.
In one embodiment, the chemical storage system 112 is connected to the
blending unit
and can include tanks for breakers, gel additives, crosslinkers, and liquid
gel concentrate.
The tanks can have level control systems such as a wireless hydrostatic
pressure system and
may be insulated and heated. Pressurized tanks may be used to provide positive
pressure
displacement to move chemicals, and some tanks may be agitated and circulated.
The
chemical storage system can continuously meter chemicals through the use of
additive pumps
which are able to meter chemical solutions to the blending unit 105 at
specified rates as
determined by the required final concentrations and the pump rates of the main
treatinent
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fluid from the blending unit. The chemical storage tanks can include weight
sensors that can
continuously monitor the weight of the taiilcs and deterinine the quantity of
chemicals used by
mass or weight in real-time, as the chemicals are being used to manufacture
well treatment
fluid. Chemical storage tanlcs can be pressurized using coinpressed air or
nitrogen. They can
also be pressurized using variable speed pulnps using positive displacement to
drive fluid
flow. The quantities and rates of chemicals added to the main fluid stream are
controlled by
valve-metering control systems. The valve-metering can be magnetic mass or
volumetric
mass meters. In addition, chemical additives could be added to the main
treatment fluid via
aspiration (Venturi Effect). The rates that the chemical additives are
aspirated into the main
fluid stream can be controlled via adjustable, calibrated , apertures located
between the
chemical storage tank and the main fluid stream. In the case of fracturing
operations, the -
main fluid strean may be either the main fracture fluid being pumped or may be
a slip stream
off of a main fracture fluid stream. In one embodiment, the components of the
chemical
storage system are modularized allowing pumps, tanks, or blenders to be added
or removed
independently.
In reference to Figure 2, in one embodiment, the blending unit 105 is
connected to the
chemical storage system 112, the proppant storage system 106, a water source
202, and a
pumping grid 111 and may prepare a fracturing fluid, complete with proppant
and chemical
additives or modifiers, by mixing and blending fluids and chemicals at
continuous rates
according to the needs of a well fonnation. The blending unit 105 comprises a
preblending
unit 201 wherein water is fed from a water supply 202 and dry powder (guar) or
liquid gel
concentrate can be metered from a storage tank by way of a screw conveyor or
pump into the
preblender's fluid stream where it is mixed with water and blended with
various chemical
additives and modifiers provided by the chemical storage system 112. These
chemicals may
include crosslinlcers, gelling agents, viscosity altering chemicals, PH
buffers, modifiers,
surfactants, breakers, and stabilizers. This mixture is fed into the blending
unit's hydration
device, which provides a first-in-first-out laminar flow. This now near fully
hydrated fluid
stream is blended in the mixer 202 of the blending unit 105 with proppant from
the proppant
storage system to create the final fracturing fluid. This process can be
accomplished at
downhole puinp rates. The blending unit can modularized allowing its
components to be
easily replaced. In one embodiment, the mixing apparatus is a modified
Halliburton Growler
mixer modified to blend proppant and chemical -additives to the base fluid
without destroying
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the base fluid properties but still providing ample energy for the blending of
proppant into a
near fully hydrated fracturing fluid. The fiiial fluid can be directed to a
pumping grid 111 and
subsequently directed to a central manifold 107, which can connect and direct
the fluid via
coluiection 109, 204, or 205 to multiple wells 110 simultaneously. In one
embodiment, the
fracturing operations factory can comprise one or more blending units each
coupled to one or
more of the control units, proppant storage system, the chemical storage
system, the pre-gel
blending unit, a water supply, the power unit, and the pumping grid. Each
blending unit can
be used substantially simultaneously with any other blending unit and can be
blending well
treatment fluid of the saine or different composition than any other blending
unit.
In one embodiment, the blending unit does not comprise a pre-blending unit.
Instead,
the fracturing operations factory contains a separate pre-gel blending unit.
The pre-gel
blending unit is fed from a water supply and dry powder (guar) can be metered
from a storage
tank into the preblender's fluid stream where it is mixed with water and
blended and can be
subsequently transferred to the blending unit. The pre-gel blending unit can
be modular, can
also be enclosed in the factory, and can be connected to the central control
system.
In one embodiment, the means for simultaneously flowing treatment fluid is a
central
manifold 107. The central manifold 107 is connected to the pumping grid 111
and is
operable to flow stimulation fluid, for example, to multiple wells at
different pads
simultaneously. The stimulation fluid can comprise proppant, gelling agents,
friction
reducers, reactive fluid such as hydrochloric acid, and can be aqueous or
hydrocarbon based.
The manifold 107 is operable to treat simultaneously two separate wells, for
example, as
shown in Figure 2 via coimections 204 and 205. In this example, multiple wells
can be
fractured simultaneously, or a treatment fluid can be flowed simultaneously to
multiple wells.
The treatment fluid flowed can be of the same coinposition or different. These
flows can be
coordinated depending on a well's specific treatment needs. In addition, in
reference to
Figure 3, the connection 109 between the central manifold 107 and a well
location can be
used in the opposite direction as shown in Figure 2 to flow a production
fluid, such as water
or hydrocarbons, or return the well treatment fluid 301 from the well location
to the manifold.
From the central manifold 107, the production fluid can be directed to a
production system
303 where it can be stored or processed or, in the case of the returning well
treatment fluid, to
a reclaination system that can allow components of returning fluid to be
reused. The
manifold is operable to receive production fluid or well treatment fluid from
a first well
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location 101 wliile simultaneously flowing treatment fluid 302 using a second
connection 108
to a second well location 102. The central manifold 107 is also operable to
receive
production fluid from botli the first well location and the second well
location
simultaneously. In this einbodiment, the first and second well locations can
be at the same or
different pads (as shown in Figure 3). The manifold is also operable to extend
multiple
connections to a single well location. In reference to Figure 2, in one
embodiment, two
connections are extended from the manifold to a single well location. One
connection 109
may be used to deliver well treatment fluid to the well location while the
otlier connection
203 may be used to deliver production fluid or return well treatment fluid
from the well
location to the central manifold 107.
In reference to Figure 4, in one embodiment, the central manifold 107 can be
connected to one or more additional manifolds 405. The additional manifolds
are operable to
connect to multiple well locations 401-404 and deliver well treatment fluids
and receive
production fluids via connections 406-409, respectively, in the sanie way as
the central
manifold 107 described above in reference to Figures 2 and 3. The additional
manifolds can
be located at the well pads.
In reference to Figure 5, in one embodiment, the central manifold has an input
501
that accepts pressurized stimulating fluid, fracturing fluid, or well
treatment fluid from a
pump truck or a pumping grid 111. The fluid flows into input 501 and througli
junctions 502
and 503 to lines 504 aild 505. Line 504 contains a valve 506, a pressure
sensor 507, and an
additional valve 508. The lineis connected to well head 101.- Line 505
contains a valve 511,
a pressure sensor 512, and an additional valve 513. These valves may be either
plug valves
or check valves and can be manually or electronically monitored and
controlled. The
pressure sensor may be a pressure transducer and may also be manually or
electronically
monitored or controlled. Line 504 is connected to well head 101 and line 505
is connected to
well head 102. This configuration allows wells 101 and 102 to be stimulated
individually and
at a higher rate, by opening the valves along the line to the well to be
treated while the valves
along the other line are closed, or simultaneously at a lower rate, by opening
the valves on
both lines at the saine time. As showri in Figure 5, this architecture can be
easily expanded to
accommodate additional wells by the addition ofjunctions, lines, valves, and
pressure sensors
as illustrated. This architecture also allows monitoring the operations of the
manifold and
detecting lealcs. By placing pressure sensors 507 and 512 between valves 506
and 508 and
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valves 511 and 513 respectively, the pressure of lines 504 and 505 can be
readily deterniined
during various phases of operation. For instance, when the manifold is
configured to
stimulate only well 101, valves 511 and 513 are closed. Pressure sensor 507
can detect the
pressure within the active line 504, and pressure sensor 512 can be used to
detect if there is
any leakage, as it would be expected that the pressure in line 505 in this
configuration would
be minimal. In another embodiment, only a single valve is used along each of
lines 504 and
505. This einbodiment can be used to stimulate wells siinultaneously or singly
as well.
Furthermore, as described in reference to Figure 4, the manifold of this
embodiment can also
worlc in reverse and transfer fluid from the wellhead back through the
manifold and to the
central location. In this conflguration, input 501 can be connected to a
production system or
reclaination system, for example, and the valves along the line connected to
the wellhead in
which it is desirable to recover fluid are open. The valves along the other
lines may be open
or closed depending on whether it is desirable to recover fluids from the
weliheads connected
to those lines. Production fluid or stimulation fluid can be returned from the
wellhead to
those systems respectively. This manifold can be located at the central
location or at a
remote pad.
In reference to Figure 6, in one embodiment, the central manifold contains two
inputs
601 and 602 that accept pressurized stimulating fluid, fracturing fluid, or
well treatment fluid
from pump trucks or a pumping grid 111. Inputs 601 and 602 can accept fluid of
different or
the same coinpositions at similar or different pressures and rates. The fluid
pumped through
input 602 travels through junctions 603 and 605. The junctions are further
connected to lines
610 and 611. The fluid pumped through input 601 travels through junctions 604
and 615.
The junctions are further connected to lines 609 and 612. Lines 609, 610, 611,
and 612 may
each contain a valve 606, a pressure sensor 607, and an additional valve 608,
or may contain
only a single valve. These valves may be either plug valves or check valves
and can be
manually or electronically monitored and controlled. The pressure sensor may
be a pressure
transducer and may also be manually or electronically monitored or controlled.
When, for
example, the fluid from input 602 is desired to be delivered to well 101 only,
the valves on
line 610 are open and the valves on line 611 are closed. When the fluid from
input 601 is
desired to be delivered to well 101 only, the valves on line 609 are open and
the valves on
line 612 are closed. When it is desired that fluid from both inputs 601 and
602 are to be
delivered to well 101 -oiAy, the valves on lines 609 and 610 are open and the
valves on lines
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611 and 612 are closed. Lines 609 and 610 are coupled to wellhead 101 through
junction
616. When it is desired that fluid from input 602 be delivered to both wells
101 and 102
simultaneously, the valves on lines 610 and 611 are both open. Fluid from
iiiput 601 can be
delivered to well 101 and fluid from input 602 can be delivered to well 102
simultaneously
by closing the valves on lines 610 and 612 and opening the valves on lines 611
and 609. The
delivery of fluid to well 102 works analogously. As shown in Figure 6, the
manifold can be
easily expanded to include additional wells through additional junctions,
lines, and valves.
Fui-thermore, as described in reference to Figure 4, the manifold of this
embodiment can also
worlc in reverse and transfer fluid from the wellhead back through the
manifold and to the
central location. In this configuration, either or both inputs 601 and 602 can
be coimected to
a production system or reclamation system, for example, and the valves along
the line
connected to the wellhead in which it is desirable to recover fluid are open.
The valves along
the other lines may be open or closed depending on whether it is desirable to
recover fluids
from the wellheads connected to those lines. Production fluid or stimulation
fluid can be
returned from the wellhead to those systems respectively. This manifold can be
located at the
central location or at a remote pad.
In reference to Figure 7, in one embodiment, multiple manifold trailers 701
and 702
may be used at the central location where the stiniulation fluid is
manufactured and
pressurized. The manifold trailers themselves are well known in the art. Each
manifold
trailer is connected to pressurized stimulating fluid through pump trucks 703
or a pumping
grid 111. A line from each manifold trailer can connect directly to a well
head to stimulate it
directly, or it can further be connected to the manifolds described that are
further comlected
to well locations.
In one embodiment, of the pumping grid system 111, pumping modules can be
hauled
to the fracturing operation factory site by truck, and pinned or bolted or
otherwise located
together on the ground. Pumping equipment grid modules can be added or talcen
away to
accommodate the number of pumping units to be used on site. The pressure
manifold will
interface with the puinping equipment grid modules and support a crane. The
grid system
can be configured with various piping or electrical connections that each
pumping unit may
require for power, fuel, cooling, and lubrication. The grid system would
incorporate space to
allow access to the puinping units' main components for easy maintenance. In
reference to
Figure 8, in one embodiment of the pumping grid 111, the grid comprises one or
more punlps
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801 that can be electric, gas, diesel, or natural gas powered. The grid can
also contain spaces
or docks 810 operable to receive equipment, such as pumps and other devices,
modularized to
fit within such spaces. The pumping grid 111 can include walkways 807 that
provide access
to pumps or any other equipment doclced in the grid spaces. The grid's spaces
or docks 810
can be prewired and prepluinbed and can contain lube oil, fueling, power, and
cooling
capabilities and connections for the pumps 801 to manifold 107 (shown in
Figure 10). The
pumps 801 that connect to the grid 111 can be freestanding such as pumps 801,
or the pumps
809 can be attached to trucks 808. Pumps 809 can each contain its own fueling,
cooling,
lubrication, and power sources. Pumps 801 can rely on centralized fuel,
coolant, lubrication,
and power sources. The fuel for the pumps 801 can be supplied to the pumps 801
from a
single central fu.eling system 803 through piping or tubing well known in the
art. The pumps
801 can include hydraulic starting mechanisms. Hydraulic power for the
starting
mechanisms can be supplied to the pumps 801 from a single central power system
804 using
tubing or piping well known in the art. In the event electric pumps are used,
the power
system 804 can provide electricity to the pumps via wires. The lubrication of
the pumps 801
can also be centralized. Lubrication fluid can be supplied from a central
lubrication system
805 to the pumps 801 using tubing or piping well known in the art. Coolant for
the pumps
can be provided from a central source such as a coolant or water tower that
can generate less
noise than local fans. The grid is operable to accept connections to proppant
storage and
metering systems, chemical storage and metering systems, and blending units.
The pumping
grid can also have a crane 806 that can assist in the replacement or movement
of pumps,
manifolds, or other equipment. In reference to Figure 9, the pumping grid 111
can be
enclosed in a structure 901. The structure can be a supported fabric
structure, a collapsible
structure, a prefabricated structure, a retractable structure, a composite
structure, a temporary
structure, a prefabricated wall and roof structure, a deployable structure, a
modular structure,
a preformed structure, a mobile accommodation structure, and combinations
thereof. The
pumping grid 111 can also be partially enclosed by structure 901 and partially
exposed, as
shown by puinp trucks 808, which are connected to the pumping grid outside of
the structure
901. The puinping grid 111 can also include a ventilation system 902 that can
release
exhaust from the pLUnps and/or ventilate the inside of the structure 901.
Figure 10 shows the
pumping grid 111, the crane 806, the pressure manifold 107, and the enclosing
structure 901.
A central manifold 107 can accept connections to wells and can be connected to
the pumping
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grid. In one embodiment, the central maiufold and pumping grid are operable to
simultaneously treat both a first well head connected via a first connection
and a second well
head connected via a second connection with the stimulation fluid manufactured
by the
factory and connected to the pumping grid.
In reference to Figure 11, in some embodiments, the pumping grid can be
located at a
different pad miles away from the fracturing operations factory 100. An
auxiliary pumping
system 1102, which itself can include pumping trucks, manifold trailers 703
shown in Figure
7, or standalone pumps, can pump fracturing fluid from the fracturing
operations factory 100
through connection 1101 to the pumping grid 111. The pumping grid 111 can next
pump the
fluid to production site 101, for example. lii this way, the operations of the
fracturing factory
100 can be extended to remote pads through assembly and reassembly of the
pumping grid
111 and connection 1101.
In some embodiments, the operations of the chemical storage system, proppant
storage system, blending unit, pumping grid, power unit, and manifolds are
controlled,
coordinated, and monitored by a central control system. The central control
system can be an
electronic computer system capable of receiving analog or digital signals from
sensors and
capable of driving digital, analog, or other variety of controls of the
various components in
the fracturing operations factory. The control system can be located within
the factory
enclosure, if any, or it can be located at a remote location. The central
control system may
use all of the sensor data from all units and the drive signals from their
individual
subcontrollers to determine subsystem trajectories. For example, control over
the,
manufacture, pumping, gelling, blending, and resin coating of proppant by the
control system
can be driven by desired product properties such as density, rate, viscosity,
etc. Control can
also be driven by external factors affecting the subunits such as dynamic or
steady-state
bottlenecks. Control can be exercised substantially simultaneously with both
the
determination of a desired product property, or with altering external
conditions. For
instance, once it is determined that a well treatment fluid with a specific
density is desired, a
well treatment fluid of the specific density can be manufactured virtually
simultaneously by
entering the desired density into'the control system. The control system will
substantially
simultaneously cause the delivery of the proppant aiid chemical components
comprising a
well treatment fluid with the desired property to the blendiing unit where it
can be
iiiunediately puinped to the desired well location. Well treatnient fluids of
different
CA 02648265 2008-10-01
WO 2007/113528 PCT/GB2007/001189
13
compositions can also be manufactured substantially simultaneously with one
another and
substantially simultaneously with the determination of desired product
properties through the
use and control of multiple blending units each connected to the control unit,
proppant
storage system, chemical storage system, water source, and power unit. The
central control
systein can include such features as: (1) virtual inertia, whereby the rates
of the subsystems
(chemical, proppant, power, etc.) are coupled despite differing individual
responses; (2)
backward capacitance control, whereby the tub level controls cascade backward
through the
system; (3) volumetric observer, whereby sand rate errors are decoupled and
proportional
ration control is allowed without steady-state error. The central control
system can also be
used to monitor equipment health and status. Simultaneously with the
manufacture of a well
treatment fluid, the control system can report the quantity and rate usage of
each component
comprising the fluid. For instance, the rate or total amount of proppant,
chemicals, water, or
electricity consumed for a given well in an operation over any time period can
be
immediately reported both during and after the operation. This information can
be
coordinated with cost schedules or billing schedules to immediately compute
and report
incremental or total costs of operation.
The present invention can be used both for onshore and offshore operations
using
existing or specialized equipment or a combination of both. Such equipment can
be
modularized to expedite installation or replacement. The present invention may
be enclosed
in a permanent, semipermanent, or mobile structure.
As those of ordinary skill in the art will appreciate, the present invention
can be
adapted for multiple uses. By way of example only, multiple well sites may be
treated,
produced, or treated and produced sequentially or simultaneously from a single
central
location. The invention is capable of considerable additional modification,
alteration, and
equivalents in form and function, as will occur to those ordinarily slcilled
in the art having the
benefit of this disclosure. The depicted and described embodiments of the
invention are
exemplary only, and are not exhaustive of the scope of the invention.
Consequently, the
invention is intended to be limited only by the spirit and scope of the
appended claims.
