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RESULTS OF A COGCC-SPONSORED BASELINE ENVIRONMENTAL DATA SURVEY RATON BASIN, COLORADO

RESULTS OF A COGCC-SPONSORED BASELINE ENVIRONMENTAL DATA SURVEY RATON BASIN, COLORADO. Anthony W. Gorody, Ph. D., CPG-9798. THIS STUDY ADDRESSES WATER & GAS-RELATED ENVIRONMENTAL ISSUES ASSOCIATED WITH COALBED GAS DEVELOPMENT. METHANE SEEPS DISSOLVED METHANE IN GROUNDWATER

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RESULTS OF A COGCC-SPONSORED BASELINE ENVIRONMENTAL DATA SURVEY RATON BASIN, COLORADO

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  1. RESULTS OF A COGCC-SPONSORED BASELINE ENVIRONMENTAL DATA SURVEY RATON BASIN, COLORADO Anthony W. Gorody, Ph. D., CPG-9798

  2. THIS STUDY ADDRESSES WATER & GAS-RELATED ENVIRONMENTAL ISSUESASSOCIATED WITH COALBED GAS DEVELOPMENT • METHANE SEEPS • DISSOLVED METHANE IN GROUNDWATER • NATURAL GROUNDWATER QUALITY • POTENTIAL IMPACT TO SHALLOW AQUIFERS • WATER QUALITY • GROUNDWATER LEVELS • SCREENING METHODS, FORENSIC TOOLS, & QUALITY CONTROLS AND PROTOCOLS

  3. COGCC Survey SeaCrest ESN Rocky Mtn. Isotech KLT PETROGLYPGH COGCC Survey Seacrest ESN Rocky Mtn. Apogee Scientific USGS WSP 2288 APPLIED ECO. CEDAR RIDGE AMOCO EVERGREEN MULTIPLE DATA SETSUSED IN STUDY PRODUCED WATER DATA SEEP & GROUNDWATER DATA COAL MINE INVENTORY • COGCC Survey

  4. OBJECTIVES OF COGCC BASELINE STUDY • COLLECT, COMPILE, AND ANALYZE A VARIETY OF ENVIRONMENTAL BASELINE INFORMATION • MAKE DATA AVAILABLE TO STAFF, INDUSTRY & PUBLIC • PROVIDES DATA FOR ADDRESSING POTENTIAL ENVIROMENTAL CONCERNS ABOUT SHALLOW GROUNDWATER RESOURCES • EXAMINE DOMESTIC AND PRODUCED WATER QUALITY • IDENTIFY AREAS WITH COALBED GAS OPERATIONS THAT MAY REQUIRE FURTHER INVESTIGATION • RECOMMEND PROTOCOLS FOR FUTURE MONITORING, SAMPLING, AND ANALYSIS

  5. FROM USGS PP 1625-A

  6. COAL MINE INVENTORY DIGITIZED:Lewicki & Associates • 465 MINES IDENTIFIED • 328 MINE BOUNDARIES DIGITIZED • MINE PORTALS AND OTHER FEATURES THAT MAY EMIT METHANE DIGITIZED • LOCATION OF 1411 CORE HOLES DIGITIZED

  7. DISTRIBUTION OF DIGITIZED FEATURES

  8. EXAMPLE DEGREE OF DETAIL DIGITIZED

  9. METHANE SEEPS & DISSOLVED METHANEDOCUMENTING BASELINE CONDITIONS • SURFACE SURVEY FOR METHANE SEEPS • RECOMMENDATIONS FOR ADDITIONAL SURVEYS • DISSOLVED METHANE IN WATER WELLS • DISTRIBUTION OF DISSOLVED METHANE • METHOD USED TO IDENTIFY METHANE SOURCE

  10. GPS IRS GC Ground Level Air Intake Ports C1, CO2, Heavy HC APOGEE SCIENTIFIC GAS SEEP DATA ACQUISITION EQUIPMENT METHANE SEEPS QUANTIFIED

  11. 170 ppm in air 2,749 LINE MILES SURVEYED (Red Lines): 67 SEEPS DETECTED- WITHIN THE PURGATOIRE RIVER DRAINAGE AREA

  12. SEEPS OCCUR WITHIN AND AROUND THE OUTCROP LIMITS OF THE COAL-BEARING RATON FORMATION COAL MINES • FORMATION CONTACT • UNDER ALLUVIUM • IN STREAM VALLEYS

  13. SEEPS OCCUR IN ISOLATED PATCHES, CLUSTERS, & IN ASSOCIATION WITH MINING FEATURES ISOLATED PATCH TRINIDAD RESERVOIR MINE- RELATED HISTORIC SEEP CLUSTER EDGE PRODUCTION FAIRWAY MINE- RELATED

  14. SEEPS ASSOCIATED WITH COAL SEAM OUTCROPS

  15. SEEPS RELATED TO MINES

  16. SUMMARY OF SEEP CHARACTERISTICS ANTHROPOGENIC ORIGIN • Mine-related features • Water wells • Pipeline right-of-ways • Other utility Infrastructures • Gas production • Historic NATURAL ORIGIN • Within outcrop trace of coal-bearing formation • Formation contacts • Dominant in NW & NE-trending linear stream valley traces • Outcrop buried under shallow alluvial fill • Historic

  17. IRS IS A GOOD SCREENING TOOLCOVER A LOT OF AREA IN SHORT TIME • RECOMMENDATIONS • EXTEND IRS SURVEY TO OUTCROP BELT NEAR RECHARGE AREA OF SOUTH FORK PURGATOIRE • FOLLOW UP SCREENING TOOL WITH WALKING SURVEY USING PORTABLE FID • LOCATE AND DESCRIBE CHARACTERISTICS OF SPECIFIC SITES : CLASSIFY SOURCE • SAMPLE GAS FROM LARGER SEEPS FOR LABORATORY ANALYSIS & COMPARE TO PRODUCTION WHERE NEEDED • DETERMINE NEED FOR LONG TERM SOIL GAS FLUX MONITORING

  18. DISSOLVED METHANE IN GROUNDWATER QUANTIFIED Number of samples

  19. LARGE DISSOLVED METHANE OCCURRENCES DISTRIBUTED LIKE SEEPS ALONG CUCHARA-RATON CONTACT & WITHING RATON FM OUCTROP

  20. Isotope 12C 13C 14C Protons 6 6 6 Neutrons 6 7 8 Abundance 98.98% 1.11% trace Type Stable Stable Unstable WHAT IS A STABLE ISOTOPE? STABLE ISOTOPES ARE USEFUL TOOLSUSED TO DETERMINE THE ORIGIN OF FLUIDS AND GASES. Many elements can exist in different forms known as isotopes. They differ in the number of neutrons in the nucleus but do not differ in the number of protons. Stable isotopes are not radioactive. Carbon Isotopes: Hydrogen Isotopes

  21. LARGE RANGE IN STABLE C AND H ISOTOPES IN PRODUCED METHANE IS DIAGNOSTIC OF MIXED BIOGENIC AND THERMOGENIC SOURCES BIOGENIC THERMOGENIC

  22. DISTRIBUTION OF STABLE CARBON ISOTOPES IN METHANE AMONG ALL SAMPLES (Del 13C CH4) SPATIAL VARIABILITY SUFFICIENT FOR DIAGNOSTIC ANALYSIS

  23. DISTRIBUTION OF DEUTERIUM IN METHANE AMONG ALL SAMPLES (Del D CH4) SPATIAL VARIABILITY SUFFICIENT FOR DIAGNOSTIC ANALYSIS

  24. COMBINED, STABLE ISOTOPES OF METHANEPROVIDE EXCELLENT FORENSIC TOOL HISTORIC SEEP CLUSTER PURGATOIRE RIVER T34S-65W 1 FAIRWAY LIMIT

  25. SUMMARY DISSOLVED METHANE • DISSOLVED METHANE OCCURS WITHIN OUTCROP BOUNDARY OF RATON FORMATION • REGULAR MEASURMENT OF DISSOLVED METHANE IN WATER WELLS RECOMMENDED • STABLE ISOTOPES USEFUL FOR DETERMINING METHANE SOURCE AND FOR COMPARISON WITH GAS FROM PRODUCING WELLS

  26. COMPARING SHALLOW GROUNDWATER & PRODUCED WATER QUALITY

  27. HYDROGEOLOGIC FRAMEWORK FROM USGS PP 1625-A

  28. EXTREME HETEROGENEITY IN SEDIMENTS OF GEOLOGIC COLUMN 0-2500’ 0-1700’ 0-500’ 30-250’ From: Cornelius,C., 2002, 4th Unconventional Gas Symposium, Calgary

  29. GOOD COVERAGE OF SHALLOW GROUNDWATER IN PRODUCING AREA 300 SAMPLES FROM 266 SITES MEET CHARGE BALANCE REQUIREMENTS OF +/-10%

  30. COGCC KLT PRODUCTION PETROGLYPH SOURCE AND DISTRIBUTION OF PRODUCING WELLS SAMPLED REASONABLY REPRESENTATIVE SAMPLE SET

  31. SAMPLES COLLECTED FROM A VARIETY OF SOURCES

  32. SURFACE & SHALLOW GROUNDWATER PRINCIPALLY COMPOSED OF VARIABLE MIXTURES: Ca,Mg(HCO3)2 & Na2SO4 (SHALLOW) NaHCO3 (INTERMEDIATE) % ALKALINITY & % Na + K GOOD MAP PARAMETERS FOR GROUNDWATER

  33. PRODUCED WATER COMPOSITION MIXED NaCl & NaHCO3 WATER TYPES %CHLORIDE & TDS MAPPING PARAMETERS

  34. GENERALIZED HYDROLOGIC CYCLE FOR PURGATOIRE Ca(HCO3)2 STIFF DIAGRAMS Na2SO4 NaHCO3 NaCl 4 MAIN WATER TYPES IN THE BASIN OCCUR AS MIXTURES ADAPTED: USGS WSP 2288

  35. GROUNDWATER CHEMISTRY NOT STATIC CHANGES DUE TO MIXED SOURCES & CHEMICAL REACTIONS 1994-1996

  36. ADDRESSING COMMUNICATION BETWEEN SHALLOW AQUIFERS AND GAS PRODUCING ZONES • PUBLIC CONCERN THAT PRODUCING WATER FROM COAL IS IMPACTING AVAILABILITY OF WATER FROM SHALLOW AQUIFERS • NO REGIONAL, SYSTEMATIC MONITORING OF SHALLOW GROUNDWATER LEVELS ESTABLISHED IN THE BASIN • NEED TO DEVELOP SCREENING METHODS USING AVAILABLE DATA THAT IDENTIFY AREAS WHICH MAY BE AT RISK OF CROSS-AQUIFER COMMUNICATION

  37. APPROACH USED TO DEVELOP SCREENING TOOLS • MAP AREAS WHERE WATER WELLS AND PRODUCING WELL COMPLETIONS ARE IN CLOSE VERTICAL AND LATERAL PROXIMITY • IDENTIFY DIAGNOSTIC PARAMETERS THAT DIFFERENTIATE SHALLOW GROUNDWATER AND PRODUCED WATER • MAP KEY PARAMETERS • IDENTIFY HOW THEY VARY ACROSS THE BASIN • IDENTY HOW THEY CHANGE WITH TIME • DETERMINE WHICH PARAMETERS IN PRODUCED WATER MAY INDICATE POSSIBLE CONNECTION WITH SHALLOW AQUIFERS

  38. MOST DOMESTIC WATER WELLS ARE SHALLOW IN THE BASIN (DATA FROM SEO, AMOCO)

  39. IN SOME AREAS THERE IS CLOSE LATERAL AND VERTICAL PROXIMITY BETWEEN DOMESTIC WATER WELL & PRODUCING WELL COMPLETIONS AREAS IN GREEN: PRODUCING WELLS & GROUNDWATER WELLS COMPLETED WITHIN 100 VERTICAL FEET OF ONE ANOTHER T34S-65W DISTANCE (FT) BETWEEN COMPLETIONS

  40. ORIGIN OF BICARBONATE COMMON TO PRODUCED AND SHALLOW WATER CAN BE DETERMINED (DEL 13C DIC) GROUNDWATER SAMPLES DISTINCTLY DIFFERENT FROM PRODUCED WATER SAMPLES

  41. PRINCIPAL REACTION DUE TO LOSS OF SULFATERELATIVE SULFATE CONTENT DECREASES WITH DEPTH MIXED Na2SO4-Ca,Mg(HCO3)2 MIXED Na2SO4 -NaHCO3

  42. SULFATE USEFUL AS A SCREENING TOOL: % SULFATE CONTENT IN PRODUCING GAS WELLS

  43. PRODUCED WATER TDS EXHIBITS TWO POPULATIONS: EACH OCCUPIES A DISTINCT REGION

  44. HIGH CHLORIDE REGIONS CORRESPOND TO HIGH TDS REGIONS AMONG PRODUCING WELLS (DEEP WATER DISCHARGE)

  45. EXCESS BROMINE SEAWATER DILUTION LINE CHLORIDE- BEARING PRODUCED WATER IN HUERFANO CO. NOT DILUTE SEAWATER – DEEP SOURCE?

  46. SPATIAL AND TEMPORAL STUDY OF KLT PRODUCING WELLS: VISUALIZING AQUIFER RESPONSE • 95 PAIRS OF SAMPLES EVALUATED • AVERAGE LAG TIME BETWEEN SAMPLES 3 YRS. FROM 1999 - 2002 • EARLY DATA SET CONTAINS ALL MAJOR IONS • LATE DATA SET CONTAINS LIMITED DATA INCLUDING DISSOLVED CHLORIDE & BICARBONATE CONTENT • DATA USEFUL TO EXAMINE • COMMUNICATION WITH SURFACE • PRODUCTION COMPARTMENTATION • REGIONAL FLOW RATE BOUNDARIES • LOCAL FLOW RATE BOUNDARIES

  47. KLT WELLS COMPLETED IN VERMEJO FORMATION • MULTIPLE THIN COAL SEAM COMPLETIONS • SEAMS HAVE VARIABLE COMPOSITION • REQUIRE ENHANCEMENT TO PRODUCE • WATER AND GAS PRODUCTION RATES NOT CONSIDERED FOR THIS ANALYSIS 150’

  48. T33S-R66W T33S-R65W 18 CUTOUTS LENSES PINCHOUTS Adapted From: Cornelius,C., 2002, 4th Unconventional Gas Symposium NEARBY CROSS SECTION SHOWS VARIABILITY IN VERMEJO COAL CONTINUITY

  49. MIXED NaCl-NaHCO3 WATER TYPES PRODUCED KLT WATER COMPOSITION %CHLORIDE OR % BICARBONATE & TDS GOOD MAPPING PARAMETERS

  50. % CHLORIDE DIFFERS ACROSS PURGATOIRE RIVER EVIDENCE OF REGIONAL GROUNDWATER DIVIDE 1ST AND 2ND QUANTILE 3RD AND 4TH QUANTILE

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