U.S. patent application number 13/533632 was filed with the patent office on 2012-12-27 for process and system for treating produced water and flowback water from oil and gas operations.
Invention is credited to Benjamin R. Earl, Stephen W. Olson, Daniel N. Ziol.
Application Number | 20120325469 13/533632 |
Document ID | / |
Family ID | 47360738 |
Filed Date | 2012-12-27 |
United States Patent
Application |
20120325469 |
Kind Code |
A1 |
Olson; Stephen W. ; et
al. |
December 27, 2012 |
PROCESS AND SYSTEM FOR TREATING PRODUCED WATER AND FLOWBACK WATER
FROM OIL AND GAS OPERATIONS
Abstract
A system and method for treatment of flowback water and produced
water at an oil or gas wellhead includes a modular treatment
facility that may be installed at a well site. The modular
treatment facility includes separate and interchangeable modules
that remove undesirable contaminants. The modules may be removed
and replaced with similar modules when they are no longer effective
at removing the contaminants. The spent modules may be transported
to a regeneration center to be regenerated and transported back to
a modular treatment facility.
Inventors: |
Olson; Stephen W.;
(Pasadena, CA) ; Earl; Benjamin R.; (Laguna Beach,
CA) ; Ziol; Daniel N.; (Pasadena, CA) |
Family ID: |
47360738 |
Appl. No.: |
13/533632 |
Filed: |
June 26, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61501643 |
Jun 27, 2011 |
|
|
|
Current U.S.
Class: |
166/267 ;
166/75.12 |
Current CPC
Class: |
C02F 2101/203 20130101;
C02F 2303/16 20130101; C02F 9/00 20130101; E21B 43/40 20130101;
C02F 1/5245 20130101; C02F 1/42 20130101; C02F 2101/32 20130101;
C02F 2101/101 20130101; C02F 2103/10 20130101; C02F 1/66 20130101;
C02F 2101/006 20130101; C02F 2201/007 20130101; C02F 2101/206
20130101 |
Class at
Publication: |
166/267 ;
166/75.12 |
International
Class: |
E21B 43/40 20060101
E21B043/40; E21B 21/06 20060101 E21B021/06 |
Claims
1. A method for treating water discharged from oil and/or gas
drilling and/or fracturing operations at a well site, the method
comprising: providing a docking station at the well site; mounting
a plurality of replaceable processing modules to the docking
station; providing the discharged water to the docking station; and
processing the discharged water by passing it through the
processing modules for reducing contaminants from said discharged
water.
2. The method as recited in claim 1, further comprising: removing
the used processing modules from the docking station; and
reconditioning said used modules.
3. The method as recited in claim 2, wherein removing the used
processing modules comprises removing the used processing modules
periodically.
4. The method as recited in claim 2, wherein removing the used
processing modules comprises removing the used processing modules
after they have been used to process a certain amount of the
discharged water.
5. The method as recited in claim 2, further comprising replacing
said removed used processing modules with reconditioned
modules.
6. The method as recited in claim 1, wherein providing said docking
station comprises transporting the docking station to the well
site.
7. The method as recited in claim 1, further comprising processing
said discharged water through two organic removal treatment
modules, two metals removal treatment modules and two sealant and
selective salts removal modules.
8. The method as recited in claim 1, wherein processing the
discharged water comprises processing the discharged water by
passing it through at least some of the processing modules in
series.
9. The method as recited in claim 8, wherein processing the
discharged water further comprises processing the discharged water
by passing it through at least some of the processing modules in
parallel.
10. The method as recited in claim 1, wherein processing the
discharged water comprises processing the discharged water by
passing it through at least some of the processing modules in
parallel.
11. The method as recited in claim 1, wherein said processing
modules are modular filters.
12. The method as recited in claim 1, further comprising re-using
the water after processing in oil and/or gas drilling and/or
fracturing operations.
13. A system for treating water discharged from oil and/or gas
drilling and/or fracturing operations at a well site, comprising: a
docking station for receiving the discharged water; and a plurality
of replaceable processing modules mounted to the docking station
for receiving the discharged water from the docking station, each
module configured to reduce one or more contaminants from the
discharged water.
14. The system as recited in claim 13, wherein the docking station
is transportable to the well site.
15. The system as recited in claim 13, wherein at least some of the
plurality of replaceable processing modules are coupled to each
other in series.
16. The system as recited in claim 13, wherein at least some of the
plurality of replaceable processing modules are coupled to each
other in parallel.
17. The system as recited in claim 16, wherein at least some of the
plurality of replaceable processing modules are coupled to each
other in series.
18. The system as recited in claim 13, wherein each module is a
modular filter.
19. The system as recited in claim 13, further comprising a module
regeneration facility configured for regenerating used modules.
20. The system as recited in claim 13, comprising two organic
removal treatment modules, two metals removal treatment modules and
two scalant and selective salts removal modules.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The above referenced application claims priority to and is
based upon U.S. Provisional Application No. 61/501,643 filed on
Jun. 27, 2011, the contents of which are fully incorporated herein
by reference.
BACKGROUND
[0002] Hydraulic fracturing has significantly increased access to
and production of oil and natural gas in various locations
throughout the United States. Shale deposits approximately two
miles deep can be accessed by drilling vertically and then
horizontally to the shale deposit which contains oil and/or natural
gas once the vertical well bore has been drilled. The drilling
operation is then redirected horizontally and subsequently drilled
one to two miles through the center of the shale deposit. Once the
well bore is drilled, the horizontal portion is perforated using
explosive charges staged along the horizontal well bore.
[0003] After the well bore has been perforated, a significant
amount of water (for example, up to 5,000,000 gallons) carrying
chemicals, sand, ceramic beads, and gels are injected at very high
pressure to create fissures in the shale deposit. These fissures
are propped open by the sand and ceramic beads. This allows gas and
oil to be released from the fissures. Following injection of the
liquid, approximately 20% of the liquid returns to the surface in
the first 7 to 14 days. This water (known as "flowback water") has
concentrations of organics (oil and grease), metals (iron and
manganese), sealants (calcium and sulfates) and salts. After the
initial discharge of flowback water, the well continues to produce
oil and "produced water" which is similar in composition to
flowback water, but higher in concentration of salts.
[0004] Well drillers often import water from fresh water sources in
120 barrel tanker trucks (approximately 5,000 gallon capacity).
Because of the weight of trucks and the fragile road conditions,
trucks are often only allowed to transport at 50% load capacity.
While distance from water source to well site varies, one-way trips
in excess of 30 miles are not uncommon. There can also be
significant wait time when both loading and unloading the trucks. A
typical hydraulic fracturing operation consumes 4 million gallons
of water or 1,600 to 2,000 tanker trucks at 50% capacity.
[0005] Once the well has been drilled and hydraulically fractured,
flow back is produced at the well, and is about 20% of the input
volume. The flow back water (and later, the produced water) is
collected and transported offsite to an injection well (e.g.,
disposal well), typically 30 or more miles away. In addition to
wells created by fracturing, other oil and gas wells also release
produced water. The flowback water and produced water are generally
not treated prior to transportation, and thus, are filled with
contaminants, making transportation more hazardous. Prior to
injection, the water is often treated with biocides and scale
inhibitors so that the water does not clog or contaminate the
disposal well site. This current model is expensive, as trucking
costs are expensive, is destructive to existing roads, and is
potentially dangerous because of traffic incidents and the
potential of hazardous spills.
SUMMARY
[0006] Embodiments of the present invention include a system and
method for treatment of both flowback and produced water at the
wellhead of oil and gas operations so that the treated water may be
used by the drillers to drill new wells, for capping or shutting in
a well, etc., thus reducing the amount of fresh water required. The
system and method include a modular treatment facility that may be
installed at the well site. Separate and interchangeable modules
that remove undesirable contaminants (e.g., organics, metals,
sealants, salts, and radionuclides) are placed in the onsite
treatment facility and removed and replaced with similar modules.
After water flows through the modular treatment, it will be
suitable for reuse in a future hydraulic fracturing operation. This
will significantly reduce or eliminate the usual transportation of
contaminated liquids to an injection well or remote treatment
facility. The modular design allows for continuous operation at the
well site, as the treatment modules may be replaced and the spent
modules may be transported to a central treatment location to be
regenerated and transported back to another well site. This
significantly reduces or eliminates the necessity of transporting
contaminated liquids or liquid chemicals. The process can rely
solely on well head pressure for operational energy, thus reducing
or eliminating the need for a separate power source and reducing
the potential of spark induced explosions.
[0007] In an exemplary embodiment a method for treating water
discharged from oil and/or gas drilling and/or fracturing
operations at a well site is provided. The method includes
providing a docking station at the well site, mounting a plurality
of replaceable processing modules to the docking station, providing
the discharged water to the docking station, and processing the
discharged water by passing it through the processing modules for
reducing contaminants from the discharged water. In another
exemplary embodiment, the method further includes removing the used
processing modules from the docking station, and reconditioning the
used modules. In yet another exemplary embodiment, removing the
used processing modules includes removing the used processing
modules periodically. In a further exemplary embodiment, removing
the used processing modules includes removing the used processing
modules after they have been used to process a certain amount of
the discharged water. In yet a further exemplary embodiment, the
method also includes replacing the removed used processing modules
with reconditioned modules. In one exemplary embodiment, providing
the docking station includes transporting the docking station to
the well site. In another exemplary embodiment, the method also
includes processing the discharged water through two organic
removal treatment modules, two metals removal treatment modules and
two sealant and selective salts removal modules. In yet another
exemplary embodiment, processing the discharged water includes
processing the discharged water by passing it through at least some
of the processing modules in series. In a further exemplary
embodiment, processing the discharged water includes processing the
discharged water by passing it through at least some of the
processing modules in parallel. In yet a further exemplary
embodiment, processing the discharged water includes processing the
discharged water by passing it through at least some of the
processing modules in parallel and at least through some of the
modules in series. In an exemplary embodiment, the processing
modules are modular filters. In a further exemplary embodiment, the
method also includes re-using the water after processing in oil
and/or gas drilling and/or fracturing operations.
[0008] In another exemplary embodiment, a system for treating water
discharged from oil and/or gas drilling and/or fracturing
operations at a well site is provided. The system includes a
docking station for receiving the discharged water, and a plurality
of replaceable processing modules mounted to the docking station
for receiving the discharged water from the docking station. Each
module is configured to reduce one or more contaminants from the
discharged water. In yet another exemplary embodiment, the docking
station is transportable to the well site. In a further exemplary
embodiment, at least some of the plurality of replaceable
processing modules are coupled to each other in series. In another
exemplary embodiment, at least some of the plurality of replaceable
processing modules are coupled to each other in parallel. In yet
another exemplary embodiment, at least some of the plurality of
replaceable processing modules are coupled to each other in series
and at least some of the plurality of replaceable processing
modules are coupled to each other in parallel. In one exemplary
embodiment, each module is a modular filter. In another exemplary
embodiment, the system also includes a module regeneration facility
configured for regenerating used modules. In yet a further
exemplary embodiment, the system includes two organic removal
treatment modules, two metals removal treatment modules and two
sealant and selective salts removal modules.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic view of an exemplary modular treatment
facility.
[0010] FIG. 2 is a schematic view of another exemplary modular
treatment facility.
[0011] FIG. 3 is a top view of an exemplary modular treatment
facility with the modules removed.
[0012] FIG. 4 is a flow chart depicting a method of the present
invention.
DETAILED DESCRIPTION
[0013] Embodiments of the present invention include a system and
method for treatment of both flowback and produced water at the
wellhead of oil and gas operations so that the treated water may be
used by the drillers to drill new wells, for capping or shutting in
a well, etc., thus reducing the amount of fresh water required. The
system and method include a modular treatment facility that may be
installed at the well site. The modular treatment facility includes
separate and interchangeable modules that remove undesirable
contaminants (e.g., organics, metals, sealants, salts, and
radionuclides). The modules are containers that are configured to
remove particular contaminants. The modules may be removed and
replaced with similar modules when they are no longer effective at
removing the contaminants. The spent modules may be transported to
a central treatment location to be regenerated and transported back
to a modular treatment facility.
[0014] The modular treatment facility is a semi-permanent treatment
skid or docking station that can be placed on a well site between
the producer's separator (which separates the oil or gas and water)
and storage tanks (which stores the flowback and produced water).
However, the modular treatment facility may be placed in any
suitable location near the wellhead. The water discharged from the
separator is piped to the treatment skid. The treatment skid has
ports to hold treatment modules, each of which is self-contained,
and each of which can be removed and replaced. Each treatment skid
can contain any number of treatment modules as desired. It may be
preferable to have multiple similar treatment modules to allow for
redundancy and to allow for online hot transfer (i.e., one module
may be transferred for another like module without stopping the
flow through the treatment skid). Depicted in FIG. 1 is an
exemplary modular treatment facility 10. The modular treatment
facility 10 includes a docking station 12, an inlet 14 at one end,
and an outlet 16 at another end. The shown exemplary modular
treatment facility 10 includes two treatment modules for each of
three treatment processes. In FIG. 1, the modular treatment
facility 10 includes two organics removal treatment modules 20 and
22 (e.g., oil removal modules), two metals removal treatment
modules 24 and 26 (e.g., iron removal modules), and two sealant and
selective salts removal modules 28 and 30 (e.g., sulfate removal
modules). As shown in FIG. 1, the treatment modules may be
connected in series, however, they may also be connected in
parallel.
[0015] For example, as shown in FIG. 1, the treatment skid may
include six modules in series: two organics removal treatment
modules, two metals removal treatment modules, and two scalant and
selective salts removal modules. Alternatively, as shown in FIG. 2,
the treatment skid 112 may include two parallel systems, e.g., each
including an organics removal treatment module 120 and 122, a
metals removal treatment module 124 and 126, and a scalant and
selective salts removal module 128 and 130. The parallel system
increases the flow capacity of the system. Additionally, flow
capacity can be improved by sequentially expanding the size of the
modules in series.
[0016] The treatment skid may be passive, i.e., no outside power is
required. In this instance, the treatment skid operates off the
pressure produced by the well. That is, the flowback water and
produced water exit the well under high pressure, thus when they
are piped to the treatment skid, they are still under pressure.
This pressure pushes the water through each treatment module,
enabling the system to operate. The passive nature of the treatment
skid reduces the possibility of fire due to sparks and reduces
cost.
[0017] Each treatment skid may be optimized for a particular site.
That is, the modules may be manufactured such that elements are
selectively removed. For instance, it may be desirable to have some
elements remain in the water after treatment, and the modules may
be designed to remove most contaminants and remove some of or none
of a particular element or compound (e.g., chlorine). Additionally,
the modules may be optimized to remove the particular contaminants
found at a site.
[0018] The modules may be formed to have minimal chemical usage,
unlike conventional flowback treatment systems which often require
extensive use of chemicals. As will be described below, in an
embodiment of the present invention, chlorine tablets for use in a
metal contaminant module (to oxidize the metal), may be the only
hazardous chemicals used. However, chlorine tablets are relatively
stable for transit and thus are safer than other chemicals used for
water treatment. In addition, the modules may be closed modules.
Therefore, no chemical handling is required on site. Rather, the
modules may be manufactured and closed to prevent or reduce
mishaps. In addition, the modules may be designed to enable dry
unit transportation. That is, the modules, whether regenerated or
spent, are substantially dry during transit. The dry modules reduce
or eliminate spill risk as the contaminants are bound inside the
modules.
[0019] The exemplary docking station has a multi-slot design as
shown in FIG. 3. As shown in FIG. 3, the docking station 212
includes a slot 240 for each of the six modules shown in FIG. 1.
However, a docking station can also include additional slots so
that additional modules could be added as desired. The multiple
slots allows for including multiples of each module, which enables
online hot transfer, i.e., when two of the same modules are
included, the spent module can be removed and replaced without
stopping the flow, as the flow could, e.g., bypass the slot where
the module has been removed. The modules could be replaced when
used up using a spare module stored on site, or the modules could
be replaced periodically. The docking station may be built so that
the piping, aside from the inlet and outlet, is fully contained
within the structure. Therefore, all pipes connecting modules may
be fully enclosed within the station, for example, under the top
surface of the skid. The docking station can be fully enclosed.
This makes the system more secure from tampering. Additionally, an
enclosed docking station protects the system from changing weather
conditions. The system may also optionally include an alarm system.
The alarm could be configured to make a notification when a module
is used, when there is an error in a module, or when there is an
error in the system. The alarm could be built into the docking
station, or alternatively, built into individual modules.
[0020] The treatment modules could include modules for removing
organics, metals, salts and scalants, radionuclides, and any other
contaminants as desired. The modules may be separated or combined,
e.g., separate modules for each type of contaminant, or a single
module could be used for metal, salts, and scalants removal.
Additionally, two different modules for salts and scalants removal
could be used to remove different classes of contaminants.
[0021] Exemplary treatment modules include an organics module, a
metals module, a salts and scalants module, and a radionuclides
module. The organics module could be configured to remove oil using
various absorptive media. Suitable absorptive media includes
activated clay, activated carbon (e.g., granular activated carbon),
and diatomaceous earth. The metals module could be configured to
remove various metals, such as iron, aluminum, and other heavy
metals using an oxidation process. The metals could be oxidized
(e.g., using chlorine tablets) and then removed from the water
using Greensand, manganese Greensand, or other suitable filtering
methods. When the metals module is used subsequent to the organics
module, chlorine is not added until after oil and other are
removed, thus reducing chemical demand. The salts and scalants
removal could be configured to selectively remove salts and
scalants such as (sulfates and bicarbonates) using, e.g., pellet
crystallization. The pellet crystallization occurs in a closed
reactor, i.e., the closed module, and is a passive process that
does not ordinarily require controls. In pellet crystallization,
seed pellets are placed in the reactor and water containing like
materials flows over the pellets and creates larger crystals. The
salts and sealants removal could be designed to allow some salts or
other compounds to remain in the water. For example, the chlorine
added in the metals module could be allowed to remain in the water,
thus providing water including chlorine, which could be used to
arrest bacterial growth. The radionuclides module could be used to
remove, e.g., radium, strontium, and other nuclides using
conventional precipitation methods (e.g., yellow caking) or ion
exchange methods (e.g., using fluorine based resins).
[0022] Once treatment modules have achieved optimal absorption at
the well site, or are otherwise removed, they can be replaced with
new or regenerated modules. Prior to removal from the well site,
the modules may be dewatered by using air to blow out the water.
For instance, the flow to the modular treatment facility may be
shut down momentarily while air from a compressor (e.g., a
compressor on a transport truck) is sent through the line,
displacing the water. This results in modules that are
substantially dry, enabling safer and more economical
transportation. The removed modules are then transported to a
centralized regeneration facility where they can be treated in a
contained environment. The regeneration facility could be a large
regeneration factory serving a large number of well sites, or
alternatively, a smaller processing plant (e.g., a processing plant
contained in a trailer) could be used to serve a single or small
group of well sites. The regeneration facility has several
benefits. Such a facility can operation in all weather conditions,
and additionally, contains contaminants from release into the
environment. The regeneration facility allows for bulk handling of
materials and byproducts and reduces the number of critical staff
required, all of which help to reduce cost. The regeneration
facility also reduces permitting requirements. Compared to trucking
large amounts of water to well sites and from well sites to
disposal, a centralized regeneration facility significantly reduces
transportation exposure. One truck or other vehicle can carry
multiple modules from multiple sites, reducing the number of times
a vehicle must return to the regeneration facility. These
simplifications reduce the net number of highway miles that must be
traveled to handle produced well water byproducts. In addition, the
regeneration facility reduces risk to the environment and personnel
and enhances recovery ability. Generally, no (or minimal) site
cleanup is required at the well site, as the used modules may
simply be removed and transported to the facility. Personnel at the
well site are generally not exposed to hazardous byproducts, as the
docking station and modules are contained. The online hot transfer
capability of the system reduces or eliminates the amount of down
time at the well site. The modules may then be rehabilitated at the
central plant in a controlled environment, thus the materials and
chemicals are contained in a secure environment. In addition, the
modules may be formed to include salvageable materials, i.e., the
materials themselves may be regenerated so they can be used again
in another module. A smaller on-site processing plant has many of
these benefits, but has a reduced capacity.
[0023] The various modules described above may be regenerated using
known methods. For instance, for the above described organics
module, a kiln may be used to remove the volatile organics from the
absorptive media. Minimum start-up fuel is required, at which
point, combustion of the volatile organics is self-powered. The
waste heat that is generated may be reused. In addition, contrary
to conventional organics removal which requires the use of
chemicals and creates a type of sludge, the above regeneration
method uses less chemicals (e.g., it uses a small amount of fuel to
start up and maintain combustion) and results in a solid byproduct.
For the above described metals module, the Greensand may be
reconditioned by backwashing, i.e., pressurized water is directed
over the used Greensand. The backwashing could occur either inside
or outside of the module. The water used for backwashing could then
be filtered and pressed to remove the metal oxides by using known
filtration methods, such as gravity filtration. After being
filtered, the water could be reused for backwashing Greensand or
other purposes. For the above described salts and sealants module,
the grown crystals can simply be removed and replaced with seed
crystals. The grown salt crystals can then be resold. For the above
described radionuclide module, the process could be disposable or
regenerative. For example, the ion exchange resin could be
regenerated through known means. The radionuclide byproduct may
then be disposed of using conventional disposal (e.g., placed in
brine and left in a dead well).
[0024] An exemplary method of treating water from a well site is
shown in FIG. 4. The method includes obtaining water from a
contaminated source, such as an oil or gas well 310. Next, the
contaminated water is run through the above described modular
treatment facility 320. Water that is cleaned through the modular
treatment facility may then be used in fracturing operations, be
used for capping or shutting in a well, or for other purposes 330.
Modules may be removed from the modular treatment facility and sent
to a regeneration facility 340. At the regeneration facility,
modules are regenerated 350. The modules are then sent back for use
in a modular treatment facility.
[0025] Although the present invention has been described and
illustrated in respect to exemplary embodiments, it is to be
understood that it is not to be so limited, since changes and
modifications may be made therein which are within the full
intended scope of this invention as hereinafter claimed.
* * * * *