Managing Coal-Bed Methane Produced Water for Beneficial Uses, Initially Using the

San Juan and Raton Basins as a Model

Michael Hightower and Allan Sattler, Sandia National Laboratories

Partners and Parties Interested inCoal Bed Methane-Produced Water Management Project

UniversitiesNMSU NM Tech

ProducersConoco Phillips Williams ProductionBurlington Resources DJ SimmonsMerrion Production Dugan ProductionTerra E&P (CO) Aztec Well ServicesSynergy Operating Bayless Production

UsersPublic Service Co, NM Williams PipelineBasin Disposal RODI SystemsAztec Well Servicing Tri Energy

Resource ManagersUS Bureau of Land NM Oil ConservationManagement Division

Desalination Equipment - Biosource Inc.

Project Goals/Scope, Approach/Status

• Task 1: Develop a team of national laboratory, university, producer, resource management and environmental personnel to support and provide direction (Sandia, NM Tech). Completed, FY 04.

• Task 2: Determine characteristics of the San Juan and Raton Basins for CBM produced water quality (Sandia, NM Tech). Completed, FY 04.

• Task 3: Using San Juan and Raton Basin CBM produced water samples, evaluate pre-treatment technologies; and capacitive deionization to meet identified, rangeland rehabilitation standards by laboratory/bench scale testing. Assess operational performance and costs (Sandia, NMSU, BLM, Western Environmental). Completed, FY 05.

Project Goals/Scope, Approach/Status(Continued)

• Task 4: Based on the laboratory and the field rangeland rehabilitation results, conduct a pilot operation on location at an industry site. This includes cooperation with the NMSU Agricultural Research Center, and BLM on use of the treated water for rangeland rehabilitation. This will include permit approvals needed (Industry Partners, NMSU, BLM, NMOCD). To be completed FY 06/early FY 07.

• Task 5: Extend future work to other CBM Basins by including producers and users in pilot planning and testing.

Schedule

• Project Started in 3rd quarter FY 03• Remaining Work

– Complete documentation of laboratory and basin characterization, 2nd quarter, FY 06

– Plan Pilot Demo 1st , 2nd quarter, FY 06 (Scope depends on additional funding availability)

– Conduct Pilot Demo 3rd, 4th quarter, FY06– Final Documentation 1st quarter, FY 06

Benefit to Oil and Gas Industryand to the Region

• Cut disposal cost of produced water by 50% for the San Juan Basin

• Assure maintenance, expansion of CBM gas production

• Beneficial use for CBM produced water found

• Provide vehicle for rangeland rehabilitation/enhancement

• A source of “new” water created in arid CBM producing regions

• A severe environmental liability is turned into an asset

Technology Transfer

• Paper presented, published in proceedings of 2005 Solar Work Congress, Orlando, Florida, August 05.

• Published paper, New Mexico Geology, Vol. 23, No. 4, Nov. 03, pp. 95-110, • Published paper, NM Bureau of Geology and Mineral Resources quarterly, New

Mexico Earth Matters, Winter 04.• Paper published in Schlumberger Oilfield Review, Summer 04.• NMSU Ag Science Center, two statewide reports, Feb. 2004, Feb. 2005.• Papers presented at New Mexico Water Resources Research Institute annual

workshops, 2004, 5, 6.• Papers presented at annual meetings of the Groundwater Protection Council

2004,5,6.• Meetings, written updates, and oral presentations of capacitive deionization

technology to producers 2003, 4, 5. • Presentations to officials of New Mexico Bureau of Geology and Mineral

Resources’ Managers, July 05.• Poster shown at the Four Corners (Farmington, NM) Oil Show 2004 and

arrangements made for poster at 2006 Oil Show with oral presentation. • Presentation for Integrated Petroleum Consortium, Houston, November, 2005.• Paper submitted, to be presented at Libyan Conference on Desalination and

Water Purification, January 06.

Relationship toOther Research Projects

• US Bureau of Reclamation/Sandia Inland Desalination Research Facility (Bench Scale Desalination)

• US Bureau of Reclamation Pilot Study in Permian Basin (Leveraged)

• State of New Mexico Governors Water Initiative (Pilot Desal Projects)

• Sandia Desalination Program (Basic and Advanced Desalination Research)

FY 06 Funding, To Date(K$)

DOEFY 04 240FY 05 300FY 06 300

FY06 Capacitive Deionization, San Juan, Raton Basins

State of New Mexico (NMSBA) 60NMSU (in kind) ~ 35ConocoPhillips (in kind at site)~70Other Four Corners Partners (In kind) ~ 25

FY 06 Reverse Osmosis, Permian BasinWestern Environmental ~35US Bureau of Reclamation ~175Other Sandia 50State of New Mexico, County ~40

Large Cost of Water Disposal from Coal-Bed Methane Wells

• Coal-bed methane (CBM) supplies 7% of US natural gas; expected to double in next decade

• Approaching 10,000 CBM wells in San Juan Basin

• To access methane, large volumes of brackish water must be removed, a severe environmental problem

• Disposal $1-4/bbl for producers in northern NM due to remoteness, lack of infrastructure, away from the electric grid

• To lower cost, methods for treating/reclaiming water sought

Raton Basin

San Juan Basin Produced Water Salinity

• Large number of wells discharge low TDS water

• Fewer wells discharge high TDS water

• With treatment, many of these wells are good candidates for water recovery and reuse

1216189

10171911

1321

26232422202520a

43251

67

14

15

0 20000 40000 60000 80000TDS (ppm)

Typical San Juan Basin CBM Produced Water

• Total Suspended Solids collected and analyzed by SEM show high silica, calcium, and iron

• Total Dissolved Solids analyzed by ICP-MS show high levels of sodium chloride

TDS 5790Sodium 2020Potassium 14Calcium 7Magnesium 11Chloride 1360Sulfate 21Alkalinity 3400Hardness 63

Rangeland Rehabilitation and Use of CBM Produced Water

• ~4000- ~12,000 TDS untreated CBM produced water has been used to water in seedlings

• Goal: 1000-1500 TDS water desired, for rangeland improvement

Rangeland Improvement (Integral/Leveraged Activity)

• Best grass seedlings for harsh southwest environment determined.• Results of watering with ~4000, ~5000 and ~12,000 TDS produced

water – Limited irrigation, focus to establish (jump start) grasses– The Sodium Absorption Ratio (SAR) and Electrical Conductivity

(EC) of the soil rose only slightly. – Soil conductivity and Sodium Absorption Ratio values remain under

critical limits for forage production for most grasses planted • Chief Intermediate Wheatgrass, Hy-Crest Crested Wheatgrass,

and San Louis Slender Wheatgrass had best overall rating for stand establishment

• Land Management Agency Guidance, ~1500 TDS water

Reverse Osmosis vs.Capacitive Deionization

Reverse Osmosis (RO)• Mature technology• Extensive water

pretreatment• Reclaimed water always

high purity• High energy associated

with pumping is hard to reclaim

Capacitive Deionization• Incipient technology• Filtering necessary,

chemical pretreatment?• Purity of reclaimed water

can be specified• In principle, high energy

associated with capacitor charging can be partially reclaimed – compatible with photovoltaics

Objectives of Current Desalination Technology Study

• Analyze, correlate lab-scale Capacitive Deionization (CDI) results– Energy use (W-hr/gal)– Yield (gal treated/gal fed)– Selectivity for specific ions

• Couple Capacitive Deionization with photovoltaic power– Solar cell, battery size and cost– % utilization of CDI (fraction of time CDI runs)

• Estimate pilot-scale system cost– Power recovery from CDI plates– CDI material cost

–+

Lab-scale Capacitive Deionization Desalination System

• ~15 gal/hr demo unit

• Electrode materials not optimum in minimized cost or maximized capacity

• Single-stage system—limited yield at high TDS, coulombic efficiency 50%

• Recovers no power from capacitor—in principle, 70-80% may be recovered

• Tests monitored– Energy use– Flow rate of inlet, outlets– Concentration of inlet,

outlets

Results – Treated Water Yield

• Model at right based on FTC mass balance:xf = y*xD + (1-y)*xC

• Large changes in dilute stream concentration have little effect on yield

• To move these curves upwards, multiple stages required

• Membrane fouling observed at end of testing– Investigating causes– No antiscalent or biocides

used

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0 2000 4000 6000 8000 10000

Feed TDS, mg/L

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FeedTDS

Yield

DiluteTDS(500 shown)

Concentrate TDS = 16500

Lab-scale Test Results

• CDI unit appears to remove all ions in similar quantities regardless of valence or mobility

• Arsenic removed from solutions of concentration 8 to 45 ppb (separate project, not CBM)

• Membrane fouling observed at end of testing– Investigating causes– No antiscalent or

biocides used

% RemovalSO4

2- 96%Cl- 96%K+ 95%Na+ 93%Mg2+ 99%

Results – Electrode Energy Usage

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10000 TDSpredicted

Case 2

Pilot Scale System– PV Considerations

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Case 3: CDI sections engaged in morning, disengaged in afternoon(23% CDI utilization)

CDI Stack Cost

Battery charge, kW-hr (left)

Case 2: CDI runs 7 hr/day, PV has storage for day operation only(25% CDI utilization)

Case 1: CDI runs 24 hr/day, PV has storage for night/day operation(86% CDI utilization)

Usable solar, kW (right)Power demand, kW (right)

PV Cost

OtherCost

Case 1

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Conclusions(Capacitive DeionizationDesalination Technology)

• Capacitive Deionization is a promising desalination technology

• Water disposal cost for a 1st-generation system with PV is approximately $1.60 per barrel (4¢/gal)

• May be cost-effective in remote locations where disposal cost is $1-4 per barrel (2-10¢/gal)

• Will conduct pilot test in CY ’06 using multiple stages to assess and optimize performance at a CBM well site

Reverse Osmosis Studies in the Permian Basin, Leveraged Activity)

• Use of ultra filtration membranes for removal of organic material was considered highly successful or processed water during downtime.

• Planning to set up for removal of H2S to protect RO membrane

• Results show that nano filtration is efficient for removal of divalent ions. Applications where nano filtration alone sufficient to (partially) desalinate produced or generally brackish water