DE-FE0000847

Goal
The goal of this project is to identify a reliable and cost-effective pre-treatment methodology for use in processes employed to treat and re-use field-produced brine and fracture flowback waters. The objective is to develop a mobile, multifunctional water treatment capability designed specifically for “pre-treatment” of field waste brine by conducting a side-by-side comparison between this new technology and that already existing in field operations.

Performers
Texas A&M University
Argonne National Laboratory
Los Alamos National Laboratory
Houston Advanced Research Center
Sam Houston State University
Rensselaer Polytechnic Institute

Collaborators
New York State Research Development Authority (NYSERDA)
MI SWACO

Background
Shale gas development relies heavily on the hydraulic fracturing process in order to maximize the economic viability of each new well. Many new wells are horizontal wells that require up to 5 million gallons of water (typically fresh water) for each frac job. Not all regions of the country possess sufficient unallocated fresh water resources to fulfill the “new water” requirements needed for each frac job. Additionally, there are numerous regulatory agency/community questions and concerns, particularly with respect to the safety of the hydraulic fracturing process and its potential to harm the environment, regarding the development of these new areas. It is clear that the human dimension of the challenge of developing Marcellus gas resources cannot be neglected.

The challenge is to identify technologies and approaches for treating the frac water that returns to the surface following a frac job (frac flowback water) for beneficial re-use in other applications, thereby conserving other local freshwater supplies. One important application would be to treat the water so that it could be reused in subsequent frac jobs. The demonstration of such technologies in field applications is needed to provide industry, policy makers, and the public with the information they need to make better decisions regarding the development of critical energy resources.

Technologies must:

• Be technically practical (e.g., work in remote field settings, offer dependable performance over extended time periods, and be easily moved from one site to another)
• Be acceptable to regulatory agencies (e.g., do not create unacceptable environmental impacts)
• Create water with chemical and physical properties that allow for good frac performance (remove contaminants and make end-product water suitable for use at a range of geochemical conditions)
• Be affordable (keeping the cost of treating water and managing any byproduct residuals as low as possible)

This project consists of eight tasks that demonstrate frac water pre-treatment technology in field operations. Successful completion of these tasks will prove this technology’s ability to remove constituents from the high salinity flowback water and produced brines encountered in the Marcellus region—and accomplish this with minimal chemical usage and no adverse environmental impact.

Impact
Re-use of frac flowback water and produced brine is a key to the successful development of shale natural gas resources. The recovery of more than 50 TCF of potential natural gas reserves found in the Marcellus Shale hinge on finding environmentally acceptable solutions to frac flowback and produced water management issues. Successful completion of the project would provide a system to cost-effectively treat and reuse flowback water in future hydraulic fracture operations to meet most future water supply requirements for shale gas wells.

The ability to cost-effectively treat and reuse flowback water for future frac jobs would greatly mitigate problems associated with fresh water usage in shale gas wells. Further, pre-treatment of frac flowback brine is essential in the Marcellus Shale region due to the limited availability of deep well disposal facilities for handling discharged brine. The specific benefits of this project will be realized when field evaluations employing different, highly-mobile pre-treatment technologies, demonstrate the ability to convert highly saline flowback water to a moderate salinity.

Accomplishments
Seven types of water treatment technology were tested as a shakedown test at the Eagle Ford Shale. The components and the analytical sampling scheme along the process train are shown in Table 1. Oil removal (Mycelx, Polymer Ventures, ABS), Microfilter (hollow fiber, ceramic, stainless steel), and Nanofilters (spiral wound) were the optional treatment technologies. Reverse Osmosis membranes and the chemical cleaning system were not evaluated during the trial run. The analysis plan shows how a particular analytical method is being used to evaluate the functionality of each step in the process train. The analytical tests were performed on-site or collected in vials for later analysis at an environmental laboratory.

Table 1. Process Train Schematic

Field operations were performed in the following manner. The first test series (Tests 1 and 2) measured the ability of different materials to selectively remove hydrocarbons and other petroleum components from frac pond brine. Test 2 flowed 2 gpm through the media filters. Initial frac pond brine was pumped through a sock filter (10 micron nominal), then Mycelx media filter, and then ABS BETEX removal. Filtrate (permeate) was collected in an oil free brine tank for subsequent micro filtration. Test 2B repeated the first test using a Polymer Ventures filter instead of the Mycelx filter. Test 3 evaluated the effectiveness of the micro-filters to remove total suspended solids (TSS) after hydrocarbon (oil, grease, and BETEX) removal. Test 3A evaluated TSS removal with a ceramic filter. This filter utilizes cross flow filtration at high pump rates to reject solids greater than 0.2 micron in size. Oil-free brine was pumped across the filter and permeate collected for turbidity measurements. Test 3B was conducted in the same manner as Test 3A with the substitution of the Graver stainless steel micro-filter. Test 3C was conducted in the same manner as Tests 3A and 3B using a hollow fiber micro-filter for solids rejection. The last test series (Test 4) measured the ability of the nano-filter to remove certain dissolved solids (salts) from the solids-free brine.

Identification of pretreatment technologies for field operations deployment has been completed. Tests have validated performance of the pre-filtration process train to determine operating cost, separation efficiency, and product water quality.

The chief accomplishment has been the development of a “chemicals free” methodology of removing contaminants from highly saline oil field produced brine. This accomplishment holds promise of a more environmentally friendly way to manage produced and frac water flowback from Marcellus gas shale drilling.

A preliminary engineering model has been developed to provide early indications of the capital and operating costs. This model-derived data is being used as a template for evaluating the efficiency of field units having varying configurations. Toward the end of the initial phase, a field test plan was developed for deploying the mobile unit to each field test site. This plan includes the selection and sequence of the field tests.

Current Status (November 2011)
Laboratory and pilot plant testing is continuing.

A mobile field laboratory has been constructed and is being outfitted with each of the process train components. Flow testing is underway to verify correct operations.

Specific site assessments and pilot plant brine sampling tests are planned for the coming months.

Results of preliminary tests performed in the field to identify the most promising types of technology for treating hypersaline brine are being analyzed and new types of methodologies are being planned. The site of these preliminary field tests, Boonville Texas (Boonville Chert Field), offered a convenient location, high salinity brine (110,000 TDS), and a willing operating company (YD Operating Company).

A three day mobile unit trial run with produced brine water was conducted in May, 2011 at Texas A&M’s Riverside facility to test changes made in the mobile unit after the initial Eagle Ford field trial conducted in February. The field unit was used at a Herkimer Site in September. Data analysis is pending. Tests are planned at two Marcellus sites during the spring of 2012.

Project Start: October 1, 2009
Project End: June 30, 2012

DOE Contribution: $466,665
Performer Contribution: $450,000

Contact Information:
NETL - John Terneus (John.Terneus@netl.doe.gov or 304-285-4254)
Texas A&M University - Dave Burnett(burnett@pe.tamu.edu or 979-845-2274)
If you are unable to reach the above personnel, please contact the content manager.

Additional Information:

Technology Status Assessment [PDF-75KB]