Note: Descriptions are shown in the official language in which they were submitted.
I.
A BLENDER HOPPER CONTROL SYSTEM FOR
MULTI-COMPONENT GRANULAR COMPOSITIONS
FIELD OF THE INVENTION
[0001] The present invention relates to systems and methods for
controlling the
entry rate into a hopper and the exit rate of materials from the hopper at a
remote
blending site for large quantities of multi-component granular compositions.
In
particular, the present invention relates to a system for regulating the
delivery rate of a
blend mixture into a blender hopper, regulating the exit rate of the blended
mixture from
the blender hopper, and coordinating the flow of materials into and out of the
blender
hopper.
BACKGROUND
[0002] Granular materials, such as sand. are used in bulk quantities in a
number of
applications. For example. mining companies sometimes make use of a technique
termed
"hydraulic fracturing'' to aid in the extraction of fossil fuels from well
sites. Hydraulic
fracturing is the propagation of fractures in a rock layer caused by the
presence of a
pressurized fluid. Hydraulic fractures form naturally, as in the case of veins
or dikes, and is
one means by which gas and petroleum from source rocks may migrate to
reservoir rocks.
[0003] In some cases, oil and gas companies may attempt to
accelerate this process
in order to release petroleum. natural gas, coal seam gas, or other substances
for extraction,
where the technique is often called "fracking" or "hydrofracking." This type
of fracturing is
done from a wellbore drilled into reservoir rock formations. The energy from
the injection of
a highly-pressurized fracking fluid creates new channels in the rock which can
increase the
extraction rates and ultimate recovery of fossil fuels. When done in already
highly-
permeable reservoirs such as sandstone-based wells, the technique is known as
well
stimulation. Operators typically try to maintain fracture width or slow its
decline following
treatment by introducing a proppant into the injected fluid. A proppant is a
material, such as
grains of sand, ceramic. or other particulates. that prevents the fractures
from closing when
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the injection is stopped. Consideration of proppant strengths and prevention
of proppant
failure becomes more important at deeper depths where pressure and stresses on
fractures
are higher.
[0004] Hydraulic fracturing, often performed in remote areas, uses
large amounts of
granular material that must be shipped into the site. The large amount of
granular material
required in a fracking operation at a well site requires that these materials
be stored close to
the well site so that they may be used as needed. Usable storage space at well
and drilling
sites is frequently very limited due to the terrain at the well sites or other
factors related to
the inaccessibility of the sites. As a result, storage space for materials
necessary for drilling
and mining operations is often at a premium. Improving the efficiency and use
of storage
space at drilling and well sites can have important economic as well as
practical benefits for
drilling and mining operations.
[0005] Typically, tractor trailer rigs are used to transport these
materials to well
sites. If no or insufficient storage space is available at the well site, it
is oftentimes necessary
to store the materials in the same tractor trailer rigs that delivered the
materials to the well
site. This is an inefficient and frequently cost-prohibitive solution to the
storage problem
because the trailers must be parked until needed. This is costly because the
drivers and their
trucks are forced to waste valuable time out of service. Thus, the efficient
storage of
materials at oil and natural gas well sites is a critical factor in the
successful implementation
of fracking operations.
[0006] In addition, to the need for an efficient on-site storage
system, there is an
existing need for a means to efficiently control the mixing of the stored
granular material to
produce a prescribed blend of materials to form the desired proppant including
systems and
methods for regulating the delivery rate of a blend mixture into a blender
hopper, regulating
the exit rate of the blended mixture from the blender hopper into the blender,
and
coordinating the flow of materials into and out of the blender hopper.
SUMMARY OF THE INVENTION
[0007] The present invention relates to systems and methods for
controlling the
entry rate into a hopper and the exit rate of materials from the hopper at a
remote
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blending site for large quantities of multi-component granular compositions.
In particular,
the present invention relates to a system for regulating the delivery rate of
a blend mixture
into a blender hopper, regulating the exit rate of the blended mixture from
the blender
hopper, and coordinating the flow of materials into and out of the blender
hopper.
[0008] Certain exemplary embodiments can provide a blending system
comprising:
(a) a hopper that blends at least two granular ingredients into a blend
mixture; (b) a blender
that lends the blend mixture received from the hopper with a liquid to form a
fracturing
fluid slurry; (c) a plurality of storage containers, wherein at least one
storage container
contains each ingredient of the blend mixture; (d) a central feeder oriented
such that a first
end of the central feeder is positioned to deliver the ingredients of the
blend mixture
directly into the hopper; (e) an ingredient feeder designated for each
ingredient in the blend
mixture, each ingredient feeder oriented to deliver the ingredient exiting
from one storage
container to the central feeder; (f) a plurality of ingredient feeder
regulators, wherein one
ingredient regulator controls the rate of delivery of each ingredient feeder
from its
ingredient feeder to the central feeder; (g) a central regulator that controls
the speed of the
central feeder and the rate of delivery of the ingredients from the central
feeder into the
hopper; (h) a hopper inflow monitor positioned at the first end of the central
feeder to
measure an amount of blend ingredients entering the hopper; (i) a variable
hopper outflow
dispenser that delivers the blend mixture into the blender; (j) a hopper
outflow regulator
that controls an exit rate of the blend mixture from the hopper by controlling
a speed of the
hopper outflow dispenser, wherein the exit rate of the blend mixture from the
hopper is
regulated based on the amount of granular material required to match the entry
rate of
liquid entering the blender to achieve a programmable setpoint of solid/fluid
ratio in the
blender, and wherein an amount of fracturing fluid slurry exiting the blender
equals the
amount of granular material and liquid entering the blender; and (k) a hopper
control
system in communication with the feeder regulators, the hopper inflow monitor,
and the
hopper outflow regulator, wherein the hopper control system matches the
delivery rate of
each of the ingredients into the hopper proportionately with the designated
percentage of
that ingredient within the blend mixture and matches the delivery rate of the
blend mixture
into the hopper with the exit rate of the blend mixture from the hopper.
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[0009] Certain exemplary embodiments can provide a blending system
comprising:
(a) a hopper that blends at least two ingredients into a blend mixture; (b) a
flat platform
positioned on a ground surface and configured for a trailer to drive upon;
(c) a plurality of storage containers, each container vertically positioned on
the platform on
a set of legs and equipped with a storage container monitoring device that
dynamically
monitors a level, mass or amount of an ingredient contained in that storage
container and
a discharge exit port oriented on a lower end of the container toward the
platform and
among the legs, wherein at least one storage container contains each
ingredient of the blend
mixture; (d) a choke gate mounted on the exit port of each container, wherein
an adjustable
opening of the choke gate controls a discharge rate of the ingredient through
the exit port
of each container; (e) a central feeder oriented proximal to and parallel to
the platform,
wherein the hopper is positioned at a first end of the central feeder such
that the central
feeder delivers the ingredients of the blend mixture into the hopper; (f) at
least one
ingredient feeder designated for each ingredient in the blend mixture, each
ingredient
feeder mounted below one container choke gate and oriented to deliver the
ingredient
exiting from the choke gate of that storage container to the central feeder;
(g) a central
regulator that regulates a variable delivery rate of the blend mixture from
the central feeder
into the hopper; (h) a plurality of ingredient regulators, with at least one
ingredient
regulator designated for each ingredient feeder, where each ingredient
regulator regulates
a variable delivery rate of the ingredient from its ingredient feeder to the
central feeder; (i)
a hopper monitor positioned proximal the first end of the central feeder
wherein the hopper
monitor measures a level, mass or amount of the blend mixture entering the
hopper or
within the hopper; (j) an adjustable hopper outflow dispenser that varies an
exit rate of the
blend mixture from the hopper to a blender, wherein the exit rate of the blend
mixture from
the hopper is regulated based on the amount of granular material required to
match the
entry rate of fluid into the blender and a programmable setpoint of
solid/fluid ratio in the
blender; (k) a hopper control system in communication with the hopper monitor,
the hopper
outflow dispenser, the storage container monitoring devices, each ingredient
feeder
regulator, and the central feeder regulator, wherein the control system is
configured to
dynamically balance the delivery rate of the blend mixture into the hopper
with the exit
rate of the blend mixture from the hopper and to regulate each ingredient
feeder regulator
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to adjust the delivery rate of each of the ingredients onto the central feeder
to equal a
designated percentage of that ingredient within the blend mixture; (1) a
blender that blends
the blend mixture received from the hopper with a liquid to form a fracturing
fluid slurry;
and (m) a blender controller in communication with a blender fluid inflow
meter, a blender
outflow meter, and the hopper control system.
[0010] Certain exemplary embodiments can provide a method for
balancing the
inflow and outflow of material into and out of a blender during a fracking job
comprising:
(a) providing a blender with a fluid inflow monitor to measure an amount of
fluid entering
the blender; (b) providing a regulatable pump to deliver the fluid into the
blender;
(c) providing a regulatable hopper outflow dispenser that delivers a blend
mixture from a
hopper to the blender; (d) calculating a mass or amount of blend mixture
required by the
blender to achieve a predetermined setpoint of solid/fluid ratio in the
blender; (c) regulating
a regulatable hopper outflow dispenser to deliver the calculated mass or
amount of blend
mixture from a hopper to the blender; (f) balancing the mass or amount of
blend mixture
and fluid entering the blender with a mass or amount of fracturing slurry
exiting the
blender.
[0011] The foregoing has outlined rather broadly several aspects
of the present
invention in order that the detailed description of the invention that follows
may be better
understood. Additional features and advantages of the invention will be
described
hereinafter which form the subject of the claims of the invention. It should
be appreciated
by those skilled in the art that the conception and the specific embodiment
disclosed might
be readily utilized as a basis for modifying or redesigning the structures for
carrying out
the same purposes as the invention. The foregoing has outlined rather broadly
several
aspects of the present invention in order that the detailed description of the
invention that
follows may be better understood.
=
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Appended Figures 1-5 depict certain non-limiting
embodiments of the
storage and blending system and related systems. The figures are not intended
to limit the
scope of the invention but, instead, are intended to provide depictions of
specific
embodiments,
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features and non-limiting characteristics of the systems described herein. The
accompanying
figures further illustrate the present invention. The components of an
embodiment shown in
the drawings are not necessarily drawn to scale, emphasis instead being placed
upon clearly
illustrating the principles of the present invention.
[0013] FIGURE 1 is a schematic illustration of one embodiment of a storage
and
blending system.
[0014] FIGURE 2 depicts a modular storage and blending system
having an
arrangement of six silos positioned vertically on two separate base platforms
with a central
conveyor between the two platforms.
[0015] FIGURE 3 is a schematic representation of one embodiment of a
storage and
blending system.
[0016] FIGURE 4 is a flowchart illustrating a process for
monitoring the content
levels within the silos.
[0017] FIGURE 5 is a flowchart illustrating one embodiment of a
blender hopper
control system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The present invention relates to systems and methods for
controlling the
entry rate of material into a hopper and the exit rate of materials from the
hopper at a
remote blending site for large quantities of multi-component granular
compositions. In
particular, the present invention relates to a system for regulating the
delivery rate of a
blend mixture into a blender hopper, regulating the exit rate of the blended
mixture from
the blender hopper, and coordinating the flow of materials into and out of the
blender
hopper.
[0019] Unless specifically defined herein, all technical and scientific
terms used
have the same meaning as commonly understood by one of ordinary skill in the
art to
which this invention belongs. The term "granular material" is used to define a
flowable
material comprising solid macroscopic particles, such as sand, gravel, or the
like. The
term "proppant" is used to define a granular material used in drilling, for
example by oil
and gas industries. Proppant comprises appropriately sized and shaped
particles which
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=
may be mixed with fracturing fluid for use in a hydraulic fracturing
treatment. A
proppant is a material such as naturally occurring grains of sand of a
predetermined size,
or engineered materials, such as resin-coated sand, ceramic materials,
sintered bauxite, or
the like.
[0020] As used
herein, the term "about" refers to a +/-10% variation from the
nominal value. It is to be understood that such a variation is always included
in a given
value provided herein, whether or not it is specifically referred to.
[0021]
As used herein, the term "component" is used interchangeably with the
term "ingredient."
[0022] One
aspect of the storage and blending system for multi-component
granular materials as described herein is schematically shown in Figure 1.
This
embodiment includes storage containers 110 for storing components or
ingredients of the
multi-component composition on-site, a primary or central feeder 130 for
feeding
materials into the blender hopper 200, and one or more secondary feeders 125
for
dispensing predetermined quantities of designated ingredients from their
storage
container 110 to the central feeder 130. The inflow of material into the
blender hopper
(also referred to herein as the hopper) 200 is monitored real time with a
hopper inflow
monitor 150. The outflow of material from the blender hopper 200 is governed
by a
regulatable outflow dispenser 240 that feeds the solid materials blended in
the blender
hopper into the blender 300. The overall coordination and control of the
inflow and
outflow of material into and out of the blender hopper 200 is managed by the
blender
hopper controller 250.
[0023]
The rate of inflow of dry material and fluids into the blender is controlled
by a blender controller 350. The rate of inflow of dry material into the
blender 300 is
based on the entry rate of fluid into the blender, as measured by a blender
fluid flow
meter 680, and a programmable setpoint of solid/fluid ratio. The blender then
blends the
incoming granular material and fluid to form a fracturing fluid slurry that is
used at the
job site (e.g., pumped into a well). The outflow of the fracturing fluid
slurry is monitored
by a fracturing slurry outflow meter 700. Thus, the blender controller 350
coordinates
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the outflow of slurry from the blender with the inflow of fluids and dry
granular materials
into the blender.
[0024] The overall coordination and control of the inflow and
outflow of material
into and out of the blender hopper 200 is important to the smooth operation of
the whole
storage and management system and is managed by the blender hopper controller
250.
The blender hopper controller 250 balances and coordinates the inflow of
material into
the blender hopper with the outflow of material from the blender hopper 200
into the
blender, which is balanced with the outflow of the blended fracturing slurry
and the
inflow of liquid materials into the blender 300.
[0025] The hopper controller is in communication with the storage container
monitoring devices, the feeder regulators that are dynamically regulated by
the hopper
control system, the hopper inflow monitor, and the hopper outflow regulator,
wherein the
hopper controller matches the delivery rate of each of the ingredients into
the hopper
proportionately with the designated percentage of that ingredient within the
blend
I 5 mixture and matches the delivery rate of the blend mixture into the
hopper with the exit
rate of the blend mixture from the hopper.
[0026] Storage of Materials at the Site
[0027] Figure 2 illustrates one embodiment of an on-site storage
system 100 that
includes six silos 110, also referred to as storage containers, arranged as
two
approximately parallel rows of three silos. Each line of three silos are
secured to a base
platform 115 with an operational section 117 at one end of each platform. A
generator or
power system 119 allows for the self contained operation of the storage and
blending
system.
[0028] Using the modular storage system 100, the storage and blending
system
can be expanded in a modular fashion to include additional silos. This modular
expansion system allows the user to expand the volume of storage for each
component
(also referred to herein as an ingredient) of a multi-component composition
(also referred
to herein as a blend mixture). For example, each modular storage system 100
added
provides an additional six silos for storage. Since each silo provides a
separate storage
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compartment, the user can house a different component or ingredient in each
silo.
Alternatively, for storing large quantities of a component, such as proppant
for a fracking
job, then each additional six silos greatly increases the on-site storage of a
component. For
example, if the user is storing proppant on-site an additional six silos
provides about
2,500,000 pounds of additional proppant storage, or a twelve silo system
enables the
pressure pumper to preload about 5,000,000 pounds of proppant or nominally one
hundred
over-the-road truckloads. This gives the pressure pumper a competitive
advantage in that
it eliminates potential delay and demurrage costs by allowing a large on-site
inventory of
proppant that is immediately available for use.
[0029] Managing the Inventory of Blend Materials at the Site
[0030] Measuring the silo contents on a real time basis is useful
for inventory
management, determining and controlling the rate of usage, and avoiding over
filling or
unexpected empty conditions. Each silo 110 may contain one or more devices for
monitoring
the level of the silo contents. The monitoring devices 315 may be sonic,
radar, optical,
inductive or mechanical level monitors.
[0031] Determining real time variations in the level, volume or
weight of the contents
of the silos and transmitting the level of component in each silo to a
programmable logic
control unit (PLC) that can automatically slow or stop the outflow of
component from a
particular silo at a pre-determined level, switch silo flows to ensure the
uninterrupted flow of
the component, or initiate the refilling of the silo to maintain the silo
level of component
within predetermined limits., The PLC orchestrates the activation,
deactivation, and
cooperation of the various components of the silo monitoring system.
[0032] The software installed on the PLC processes the data
received from a Human
Machine Interface (HMI) at its control panel, the silo level monitors, the
VFDs on the central
and secondary feeders, and a secure information processing unit (IPU).
The software
communicates information and instructions based on the processed data back to
the HMI at
the control panel, the silo level monitors, the VFDs on the primary and
secondary feeders, and
the IPU.
=
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[0033] Preferred embodiments of the PLC include diversified
communications
equipment allowing the PLC and/or the IPU to communicate with the Internet
and/or an
Ethernet. The IPU typically includes at least one of the following
communication devices: a
modem to allow the system to communicate via a "landline" internet connection
(e.g., DSL
or cable modem), a satellite antenna and/or a cellular antenna to communicate
via a cellular
. communication tower data connection The IPU communication device is designed
to
establish and maintain communications with the internet and silo technicians
that are
authorized to slow or stop the outflow of component from a particular silo at
a pre-determined
level, activate component flow from a different silo to ensure the
uninterrupted flow of the
component, or to initiate the refilling of the silo to maintain the silo level
of component within
predetermined limits.
[0034] The silos 110 may contain one or more devices 315 for
monitoring the level of
their contents. The monitoring devices may be sonic, radar, optical, inductive
or mechanical
level monitors. Measuring the contents is useful for inventory management,
determining and
controlling the rate of usage, and avoiding over filling or unexpected empty
conditions.
[0035] For example, load cells or strain gauges attached to the
silo legs 116 may be
used to weigh the contents of the silo. Another example of a monitoring device
is a pulsed
radar monitor positioned inside a silo 110 at the top portion of the silo. The
pulsed radar on
the top of the silo is used to detect the profile of the granular component in
the silo, as it takes
the angle of repose of the component into consideration and calculates an
effective level, or
weight, of the component in the silo.
[0036] As indicated in Figure 4, the silo content level may be
transmitted by a silo
level monitoring device transmitter 315 (also referred to as a silo level
transmitter) to a visual
display such as a daylight visible LED sign and/or to a human machine
interface that is visible
to the on-site operator, who can control the content level of the silo through
a programmable
logic control unit (PLC) either by slowing the discharge of component from the
silo, switching
to another silo for discharging that component, or start refilling the silo
with that component.
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=
[0037] Preferred embodiments determine real time variations in
the level, volume or
weight of the contents of the silos and transmit the level of component in the
silo to a PLC
that is programmed to automatically slow or stop the outflow of component from
a
particular silo at a pre-determined level, switch silo flows to ensure the
uninterrupted flow
of the component, or initiate the refilling of the silo to maintain the silo
level of component
within predetermined limits. This PLC-based monitoring and automatic operation
removes
the need to have visual monitoring of each silo or storage container, thereby
reducing the
number of personnel required at a given site location.
[0038] The regulation of the outflow of the component or
ingredient from a silo is
typically automated as illustrated in Figure 4. Controlling the inflow of
component, or
refilling of the silo, may be performed during the operation of the blending
system. The
silos 110 typically have one or more fill tubes or bucket elevators running up
the side of the
silo. The fill tubes or bucket elevators facilitate loading the designated
granular component
into the designated silo. A loading system such as a blower, an in-feed
elevator, conveyor,
bucket elevator, or the like, is operatively incorporated into fill tube.
[0039] Figure 4 is a flowchart illustrating a process for
controlling the content
level of components in the one or more silos in which the components are
stored. In
certain embodiments, the process may be a computer-implemented process (e.g.,
executable on the electronic control system or PLC). The electronic control
system or
PLC may implement the process by acquiring real-time operational data from the
silo
level monitors, evaluating the data against stored predetermined component
content
limits, minimal and maximal limits, and outputting appropriate control signals
in the
system.
[0040] As illustrated in Figure 4, the process includes the
step of continually
monitoring the silo contents level (block 410). The silo levels are
communicated (block
412) to a visual display (block 414) and/or to a programmable logic control
device (PLC)
(block 416). Thus, the PLC constantly acquires real-time silo content level
data from the
silo level monitors, evaluates the data against stored predetermined component
content
limits, minimal and maximal limits, and outputs appropriate control signals in
the system.
If the content level data is within the programmed prescribed limits (block
418) then the
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PLC will not initiate any change in the blending system. If on the other hand,
the silo
level contents pass outside of the prescribed limits (block 420), then the PLC
sends an
alert to the silo technician and/or the system operator. The silo technician
or the system
operator is responsible for ensuring that the situation is addressed either
manually by the
silo technician or as instructed by the PLC to initiate refilling the silo
(block 422),
slowing the discharge from the silo (block 424) by instructing the variable
frequency
drives (VFDs) of the primary and secondary feeders to slow, or to
automatically turn off
the lead or secondary feeder from the silo with a content level outside of the
prescribed
limits and to activate the discharge of that component from another silo
(block 426) .
[0041] Managing Inflow/Outflow of Blend Materials to the Blender
[0042] One embodiment of the storage system 100 for multi-
component granular
materials as described herein is shown in Figures 1-3. This embodiment
includes
multiple vertically standing storage containers for storing ingredients of the
blend
mixture on-site, a primary or central feeder 130 for feeding the ingredients
into the
hopper blender 200, one or more secondary or ingredient feeders 125 for
dispensing a
predetermined quantity of one or more different ingredients from one or more
designated
storage containers 110 to the primary feeder 130, one or more hopper blender
level
monitors that tracks the level of material in the hopper blender 200 and a
hopper blender
inflow monitor 150 that measures the exact amount of material entering the
hopper
blender 200, wherein the level of material flowing into the blender is
controlled by the
feed rate of the primary 130 and secondary feeders 125. The feed rate of the
primary
feeder 130 is controlled by a primary or central feeder regulator 135, the
feed rate of the
secondary feeders 125 is controlled by secondary or ingredient feeder
regulators 140.
The system, either in whole or in part. can be controlled either manually or
electronically.
[0043] An on-site blending system allows oil field personnel to
blend two or more
products with precision. This enables pressure pumpers to precisely blend
products for
specific well designs that call for a blend of proppants such as a coated sand
of a specific
color with another proppant, a sand that is chemically coated with a traceable
tag to allow
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the proppant to be traced down hole, or a blend of proppant and other bulk
solid additives
for tracking proppant position or performance.
[0044] Figure 2 depicts one embodiment of two rows of three silos
110 positioned
side-by-side on a base platform 115. Also depicted are shuttle conveyors 125
which are
located under the exit ports beneath each silo 110 such that the shuttle
conveyor 125 may be
used to transfer material stored in one or more silos 110 onto a dual belt
conveyor 130 or
other receiving mechanism that delivers the material to a hopper or blender
hopper 200.
[0045] The six silos 110 vertically positioned on two separate
neighboring base
platforms 115 in a "six pack" configuration. In between the two rows of three
silos is a
central conveyor system 130, or primary feeder, that is fed by the shuttle
conveyors 125,
serving as secondary feeders beneath the silos. The speed of the central
conveyor system
130 as well as the shuttle conveyors 125 may be electronically controlled
using a variable
frequency drive that allows for the remote control of variation in the speeds
of the
conveyors. The central conveyor system 130 is used to transport the material
stored in the
silos 110 into a hopper or blender hopper 200. Any number of silos can be
employed at the
site by adding additional six pack configurations.
[0046] In preferred embodiments, the blending system illustrated
in Figure 3 is
designed to maintain a constant level and supply of component (which is
adjustable) from
the one or more silos to the blender hopper 200 that feeds an on-site
operation, such as a frac
job. Since the system is designed to monitor granular solids amounts in real
time, the
system can furnish the rate at which one or more components are being removed
from one
or more silos, as well as the rate of ingredient delivery into the hopper
originating from the
one or more silos.
[0047] In order to maintain an efficient on-site operation, it is
necessary to control
the rate that the blended mixture is being removed from the blender hopper 200
and to
balance that exit rate with the total inflow rate that the various components
are being
delivered to the blender hopper. In a frac job, for example, a large amount of
the blended
proppant is continuously being pumped into the well from the blender 300 so in
order that
the frac job is not interrupted due to the availability of the blended
proppant, the rate at
which each component of the blend mixture is released from the silos and
delivered into the
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blender hopper 200 must be carefully regulated. In certain embodiments, flow
of
components from each silo is controlled using detectors and is automated by a
programmable logic control unit (PLC).
[0048] The central or primary feeder 130 and the secondary feeders
125 may be a
variety of regulatable dispensers. For example, discharge chutes, gate valves,
vibratory
dispensers, augers or conveyors having adjustable speeds that can provide a
regulatable feed
rate from zero to a predetermined maximum flow of a particular component from
a silo.
[0049] Conveyors, such as the central conveyor or shuttle
conveyors described
above, serve as preferred primary and secondary feeders since they move
material, such as
sand or other solid granular material, horizontally. This allows a lower
overall installed
height than using conventional inclined chutes or augers. Variable frequency
drives are
optionally installed to allow control of the speed of the shuttle and central
conveyors and
thus the component feed rate into the blender hopper. As illustrated in Figure
2, a shuttle
conveyor 125 is typically positioned below each silo 110 on the base platform
115. The
speed of each conveyor is remotely controlled via a digital electronic system,
providing
precise control of the discharge rate of each component of the proppant to
match the
required flow of each material at the site operation.
[0050] A preferred embodiment of the primary or central feeder 130
is a dual belt
conveyor. The dual belt conveyor and the shuttle conveyors typically have
variable
frequency drives (VFD) or other feeder regulators. The gentle transitions of
the
components from the shuttle conveyors to the dual belt conveyor limit the
sifting
segregation of the blend materials as they are dispensed from the silos 110 to
the blender
hopper 200. A thorough mixing of all of the blend materials or components is
performed
inside the blender hopper 200. Since the level of material in the blender
hopper is
important, it is continuously monitored either by a designated operator or
automatically
by a level monitor.
[0051] One or more level monitors 210 track the level of material
in the blender
hopper at all times. A top level monitor and/or a bottom monitor is used to
monitor the
level of material within the blender hopper. A top level monitor 210 is
typically
positioned at the top of the blender hopper to monitor the level of material
in the blender
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CA 3048238 2019-06-28
and communicate the level of material to a blender hopper controller 250. The
top level
monitor 210 may be a sonic, radar, optical, inductive or mechanical level
monitor.
Preferred embodiments use a level sensing laser, a guided wave radar, a non-
contact
radar, or a pulsed radar device to constantly monitor the level of material in
the blender.
Generally, a bottom level monitor TO is a mechanical level monitor such as a
load cell
that communicates the weight of the blender hopper contents (in kilograms or
tons) to a
blender hopper controller 250.
[0052] The quantity of each blend component dispensed from a silo
110 to a
secondary feeder 125 and to the primary or central feeder 130 is controlled by
regulating
the feeder regulator of the secondary feeder 140 and the feeder regulator 135
of the
primary or central feeder in order to increase or slow their output speeds.
The level
transmitter will communicate to the feeder regulators of the secondary and
primary
feeders in order to increase or slow their speeds so that the level of
material in the hopper
is adjusted and maintained within predetermined limits. To ensure that the
exact amount
of inflowing material into the hopper is measured and communicated to a hopper
control
system, the rate of inflow into the blender hopper can be measured by a
monitor 150
positioned at the end of the central feeder 130 or attached to the top of the
blender hopper
200. The hopper inflow monitor 150 monitors the exact quantity of material
that drops
into the blender hopper from the distal end of the primary conveyor into the
blender
hopper.
[0053] The hopper inflow monitor 150 may be a sonic, radar,
optical, inductive,
or mechanical monitor. Some embodiments of the hopper inflow monitor use a
visual
sensing laser, a guided wave radar, a non-contact radar, or a pulsed radar
device to
constantly monitor the amount of material entering the blender. One embodiment
of the
hopper inflow monitor 150 uses a load cell under the distal end of the central
conveyor
and a speed sensor that measures the speed of the central conveyor 130. A
blender
controller 250 determines the exact amount of material passing over the distal
end of the
conveyor into the blender from the primary shuttle load cell readings and the
speed
sensor readings by totaling the weight of material passing over the load cell
per a set time
period.
CA 3048238 2019-06-28
[0054] The rate of inflow and outflow of solid materials into and
out of the
blender hopper 200 must be carefully measured and balanced. In order to get
the exact
real time rate of outflow of material from the blender hopper, a regulatable
dispenser 240
is used to control the dispensing of solid material from the blender hopper
200 into the
blender 300. For example, discharge chutes, gate valves, vibratory dispensers,
augers or
conveyors having adjustable speeds that can provide a regulatable feed rate
from zero to a
predetermined maximum flow of material out of the blender hopper.
[0055] A blender hopper dispenser regulator 270, such as a motor
governing the
speed of the hopper dispenser 240, is used to determine real time exact
outflow rates of
solid material from the blender hopper 200 into the blender 300. The
regulatable hopper
dispenser 240 is used to measure, regulate and control the rate of outflow of
material
from the blender hopper. One embodiment of the hopper dispenser 240 is an
auger. The
hopper dispenser 240 is typically regulated by a dispenser regulator 270
having a variable
frequency drive (VFD) 275 or other regulator. For example if an auger is used
as the
hopper dispenser, the outflow rate of material from the blender hopper is
controlled by
regulating the turn rate of the auger and thus the exact rate of outflow of
material.
[0056] A blender hopper controller 250 is used to balance and
control the inflow
and outflow rates of material into and out of the hopper blender. As seen in
Figure 1, the
blender hopper controller 250 communicates with the primary and secondary
feeders 125,
130; the blender hopper inflow monitor 150; the hopper blender dispenser 240;
and the
blender controller 350. The hopper controller 250 continually balances the
inflow and
outflow of material into and out of the blender hopper.
[0057] In certain embodiments, the blender hopper control process
may be a
computer-implemented process (e.g., executable on the electronic control
system or
PLC). The blender hopper controller control system may implement the process
by
acquiring real-time operational data from the blender inflow monitor 150 and
outflow
dispenser 240, evaluating the quantity of component inflow and outflow into
and from
the blender hopper and balancing the rate of inflow of components into the
blender
hopper with the rate of outflow of the blended mixture from the blender hopper
200.
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This balancing of the inflow and outflow involves controlling the dispensing
of material
into the blender hopper and the outflow of material out of the blender hopper.
[0058] The inflow of material into the blender hopper is
controlled by the
feedback regulation of the speed of dissemination of each component from a
silo within
certain predetermined limits onto the central feeder and the real time rate of
inflow of
material from the central feeder 130 into the blender hopper 200. Thus, the
rate of inflow
of materials into the hopper is controlled by speeding up or slowing down the
primary
and secondary feeders and therefore the rate of dispensing the components into
the
blender hopper. The outflow of the blend mixture from the hopper blender is
similarly
controlled by regulating the hopper dispenser 240.
[0059] Managing Inflow/Outflow of Blend Materials to the Blender
[0060] As shown in Figure 1, the hopper outflow dispenser 240
delivers the blend
mixture directly from the hopper 200 into a blender 300 based on the liquid
flow rate into
the blender and the blender slurry flow rate exiting the blender. It is
important that there
is tight control over the exact amount of granular material entering the
blender. This is
accomplished using a variable hopper outflow dispenser and a hopper outflow
monitor
that calculates the hopper outflow based on the speed of the outflow dispenser
240 and
the amount of blend material delivered per unit of time by the hopper outflow
dispenser.
[0061] A blender controller 350 controls the speed of the hopper outflow
dispenser based on the amount of granular material required to enter the
blender per a
designated time period. The entry rate of granular material into the blender
is controlled
to match the entry rate of fluid into the blender and a programmable setpoint
of
solid/fluid ratio. The entry rate of fluid into the blender 300 is typically
controlled by a
suction pump and measured by a blender fluid flow meter 680.
[0062] Once the blend mixture and fluid enter the blender 300, the
blender blends
the granular material and fluid to form a fracturing fluid slurry. The
blending process is
typically performed by a mixing process that is designed to quickly and
thoroughly mix
the contents of the blender using a mixing device inside the blender into a
homogenous
fracturing fluid slurry. The exit rate for the fracturing slurry is controlled
by a discharge
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CA 3048238 2019-06-28
pump that provides an adequate charge pressure for the frac pump. The exit
rate of the
fracturing slurry is measured by the blender slurry flow meter 700 and is
balanced with
the inflow of the blend mixture and fluid.
[0063] Hopper Control System
[0064] Currently, most systems have the rate of delivery of solid
components into
the hopper controlled manually. During a hydraulic fracturing process, it is
important
that the level on material in the blender hopper is carefully controlled. If
solid
components are delivered too quickly to the hopper then the hopper will
overflow
causing a number of safety and environmental issues on the job site. Yet if
the solid
material is delivered too slowly, then the hopper risks running dry
diminishing the
concentration of proppant being pumped down the well and compromising the
productivity of the well. The hopper control system provides a method for
balancing the
inflow and outflow of material into and out of the hopper.
[0065] The hopper controller 250 balances the flow of material into and out
of the
blender hopper 200. One embodiment of a hopper control system is illustrated
in Figure
5. The hopper controller controls the hopper inflow (step 510) by varying the
speed of
the primary (step 530) and secondary feeders (step 540) as previously
described. The
hopper controller (step 250) controls the hopper outflow of blend material by
varying the
speed of the hopper outflow dispenser (step 570). The hopper controller varies
the speed
of the hopper outflow dispenser to balance the hopper inflow and outflow of
material
while taking into account the amount of blend material needed to enter the
blender to take
in account the inflow of fluid into and the outflow of slurry out of the
blender (step 580).
[0066] A method for balancing the inflow and outflow of material
into and out
of a hopper during a fracking job is set out herein. The method includes the
steps of (a)
providing the hopper with a hopper inflow monitor positioned proximal an
entrance to
the hopper; (b) measuring a mass or amount of granular material entering the
hopper; (c)
providing the hopper with a regulatable hopper outflow dispenser that delivers
the
granular material from the hopper to a blender: (d) measuring a mass or amount
of
granular material required by the blender to produce a set amount of
fracturing slurry to
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CA 3048238 2019-06-28
pump into a well: (e) regulating the hopper outflow dispenser to deliver the
mass or
amount of granular material required by the blender from the hopper to the
blender; (e)
balancing the mass or amount of granular material entering the hopper with the
mass or
amount of material delivered to the blender.
[0067] The monitoring and operating technology of the current invention is
PLC-
based and removes the need to have visual monitoring of the silos, primary and
secondary feeders, or the blender hopper. The PLC-based operating technology
reduces
the number of technicians required at a given site location and the costly
side effects of
potential human mistakes. Preferred embodiments of the automated storage and
blending
system only requires one technician to operate the entire system, whereas
conventional
systems require up to six on-site technicians. The PLC-based storage and
blending
system allows the on-site technician or operator to adjust and change the
blending of
components through an on-site human machine interface (HMI) to meet the
changing
needs of the on-site operation.
[0068] In certain embodiments, the process may be a computer-implemented
process (e.g., executable on the electronic control system or PLC). The PLC
may
implement the process by acquiring real-time operational data from the central
and
shuttle conveyors, the silo monitors; the hopper inflow monitor; the hopper
outflow
monitor; and the blender controller.
[0069] It will be understood that each block of the flowchart illustrations
and/or
block diagrams. and combinations of blocks in the flowchart illustrations
and/or block
diagrams, can be implemented by computer program instructions. These computer
program
instructions may be provided to a processor of a general purpose computer,
special purpose
computer, or other programmable data processing apparatus to produce a
machine, such that
the instructions, which execute via the processor of the computer or other
programmable
data processing apparatus. create means for implementing the functions/acts
specified in the
flowchart and/or block diagram block or blocks.
[0070] The foregoing provides a detailed description of the
invention which forms
the subject of the claims of the invention. It should be appreciated by those
skilled in the art
that the general design and the specific embodiments disclosed might be
readily utilized as a
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basis for modifying or redesigning the natural gas supply system to perform
equivalent
functions, but those skilled in the art should realized that such equivalent
constructions do
not depart from the spirit and scope of the invention as set forth in the
appended claims.
CA 3048238 2019-06-28
