Oil & Natural Gas Projects
Exploration and Production Technologies
Zero Discharge Water Management for Horizontal Shale Gas Well Development
Last Reviewed 5/31/2011
The objective of the project is to develop an on-site multi-media
filtration system. The five-stage modular design will permit efficient
system operation and treatment of flowback water at conditions that vary
West Virginia University
Shale gas development in the Marcellus gas play in the northern
Appalachian Basin requires large volumes of water to fracture the
formation and stimulate production. Known as “frac return water”, it
and produced water are highly saline and currently require either
disposal or treatment. Both options are expensive. Produced water that
cannot be readily treated for local disposal (e.g., land application)
could be hauled to an injection well for disposal. These are EPA Class
II wells permitted under the federal Safe Drinking Water Act and are
carefully controlled and monitored. Disposal costs are well established.
In Texas, haulage and disposal costs average $1.47 per barrel. In the
more populated East, the costs range from $1.68 to $2.10 per barrel. As
an alternative to deep well disposal, produced water has been processed
at municipal or commercial treatment plants (especially in
Pennsylvania) but this practice is being re-evaluated. While this
treatment removes some contaminants, it does not address salinity and
throughput is limited by plant limitations and the ability to dilute the
effluent to meet water quality standards. This is a costly alternative
that will be less likely to be used in the future as small towns and
cities find that their standard treatment is inadequate and that they
lack the necessary existing capacity.
The more cost-effective alternative is on-site treatment of the
produced water to the degree needed for re-use as frac water. Produced
water has been successfully treated using Reverse Osmosis (RO) as the
primary treatment technology. However, extension of the RO technology to
the treatment of flow back from hydraulic fracture operations has
required pre-treatment technologies designed to extend the life of the
RO unit. RO protection is especially important during the initial frac
water return period when it will have the maximum suspended solids and
minimum dissolved solids.
Re-use technologies are just now being implemented, and as
reported in a recent overview (GWPC, April 2009): “Current levels of
interest in recycling and reuse are high, but new approaches and more
efficient technologies are needed to make treatment and re-use a
wide-spread reality.” The FilterSure multi-media filter technology
offers a new, cost-effective approach ideally suited for removing
suspended solids associated with frac return water while promising an
order of magnitude improvement in operating efficiency. The filter is
expected to replace all of the pre-treatment steps now being examined
under the DOE contract, dramatically reducing the costs and enhancing
the attractiveness of water re-use.
The successful development of an advanced FilterSure technology for
clean-up and re-use of frac return water will advance shale gas
exploitation and development through improved economics and resolution
of environmental issues. Improved economics will be achieved by the
reduction of frac return water trucking and disposal costs. By reusing
the frac return water for subsequent fractures, the need for new, fresh
frac water for future wells will be reduced by 30% to 50% depending on
the percentage of injected water that is returned after the frac. There
will be an additional cost savings due to reduced freshwater hauling and
labor costs will be minimized because the mobile unit will operate
continuously with little or no need for an attendant. Significant
environmental benefits will be derived from this technology as well.
Less fresh water will be needed for future fractures, thus lowering the
demand stress on local streams. Fewer trips with water trucks will cause
less damage to local roads, reduce fugitive dust and engine exhaust
emissions, and reduce mud and muddy water which potentially could
pollute streams. These derived environmental benefits will also provide
indirect economic benefits through reduced cost of road repairs, and
less need for local stream remediation. Perhaps the most important
benefit from cleaner and less disruptive drilling will be the “good
will” of all stakeholders affected by the shale gas development process.
Preliminary laboratory results from a recent scale test show that the 150 GPM unit is feasible.
The Design of the 30 gallon per minute (GPM) Mobile Treatment
Unit (MTU) has been completed. WVU has requested to change the MTU
design to a 150 GPM throughput unit for use during field testing.
During a recent laboratory test using actual frac return water
from a site similar to the upcoming test site, WVU concluded that the
new filter unit captured particulate at and greater than 3 microns.
Current industry requests are equal to or greater than 20 microns,
showing that even at the high throughput the filter unit exceeds current
No Naturally Occurring Radioactive Materials (NORMs), have been
found in any of the field samples of frac return water received
to-date. Any heavy metals will be removed via insoluble complexes for
Heavy metals and radioactive elements/compounds, if any, were
contained in the EC-mobilized solids removed by filtration and managed
as a part of the commercial process. Tests on the filter backwash
waters following treatment of each sample showed “non-detect” levels for
As, Cd, Cr, Pb, Se, Ag, and Hg. Barium was detected in amounts ranging
from 1.61 to 5.33 mg/l, well below the MCL of 100 mg/l set for Ba.
One 20-gallon sample of Marcellus frac return water was shipped
to a provider of Electrical Coagulation (EC) technology for testing as a
potential pre-treatment option. The EC-treated water was returned to
WVU for evaluation. The results show that the EC technology had a major
impact on the distribution of the solids. Specifically, the EC
technology caused the distribution of solids to shift from a few microns
in size to larger solids having a single bell-shaped distribution.
Three applications of the FilterSure PDU on Marcellus Shale
frac return water reduced the suspended solids by 76%, removing all
suspended solids greater than 3 microns in size, a good result when
compared to the most strict industry requirement of 5 microns. Other
industry operators report a 5 to 10 micron requirement or standard sand
filtration with no absolute size requirement.
Results of economic analyses indicate that the plausible system
resulting from this project will be very cost competitive with any
other system for achieving the ultimate objective of zero-discharge of
frac return water. Preliminary estimates place the cost at $0.80 to
Suspended solids in the EC treated water were easily removed
with the FilterSure technology resulting in an effluent that was
visually clear without particulates. The combination EC and FilterSure
PDU treatment system removed 99.4% of all particles.
Electrical Coagulation (EC) shifted the distribution of the
suspended particles, creating larger size particles compared with the
raw water sample.
Industry Contact Group members have provided five flowback frac
water samples. The WVU Radiation Safety Department tested all samples
for radioactivity and found all to be at or below background values. WVU
analyzed particle size distribution for all frac return water samples.
A commercial laboratory and WVU measured the water chemistry of all
samples. Tests of Marcellus water samples showed the FilterSure process
development unit (PDU) removed 100% of the frac water suspended solids
larger than three microns and 40% of particles larger than 1.5 microns.
Responses to a questionnaire developed for this project are
providing engineering information on volumes of flowback water and water
chemistry requirements for recycling of flowback water.
An Industry Contact Group was created to obtain representative water flowback samples and information on operating parameters.
Current Status (May 2011)
The design phase of the 150 GPM unit has been completed. Testing of the
6GPM MTU in the laboratory has shown that the 150GPM throughput unit
can be reached for the upcoming field test.
Project Start: October 1, 2009
Project End: September 30, 2011
DOE Contribution: $609,619
Performer Contribution: $390,381
NETL - William Fincham (email@example.com or 304-285-4268)
WVU - Dr. Paul Ziemkiewicz (firstname.lastname@example.org or 304-293-2867x5441)
Technology Status Assessment [PDF-122KB]
Quarterly Progress Report [PDF-284KB] October - December 2009
Quarterly Progress Report [PDF-279KB] January - March 2010
Quarterly Progress Report [PDF-792KB] April - June 2010
Quarterly Progress Report [PDF-678KB] July - September 2010