Regional Trends in Coalbed Gas Composition and Thermal Maturation in Eastern Kansas: Implications for Predicting Quality and Location of Coalbed Gas

Transcription

1 Regional Trends in Coalbed Gas Composition and Thermal Maturation in Eastern Kansas: Implications for Predicting Quality and Location of Coalbed Gas K. David Newell and L. Michael Magnuson Kansas Geological Survey, University of Kansas, Lawrence, KS

2 25 mi 25 km known coal bed gas projects NUMBER of WELLS DRILLED for COALBED GAS by county (through mid-23) Cowley Pottawatomie Butler Morris Marion 1 Elk 8 3 est City B 9 1 Bourbon Arch 5 22 Cherokee Bas Wabaunsee Chase Greenwood Chautauqua Nemaha Brown Jackson Shawnee Osage Coffey Woodson Wilson Montgomery 3 Atchison 4 Jefferson Douglas Franklin 6 1 Doniphan Anderson Allen 17 Neosho 234 Labette 51 Leavenworth 9 Miami Linn Wyandotte Johnson Bourbon 2 Crawford Cherokee 1 N

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4 ESTIMATED MAXIMUM PRODUCIBLE METHANE CONTENT BY DEPTH AND RANK (after Eddy, 1982; Saulsberry and others (1996)) gas content (scf/ton) gas content (cc/g).. anthracite low-vol bituminous 25 5 medium-vol bituminous high-vol Abituminous high-vol B bituminous high-vol C bituminous subbituminous C depth (feet) depth (meters) Eastern Kansas Coals 75

5 BTU/scf desorption gas (Bostic et al., 1993) BTU content for eastern KS Pennsylvanian gases (projected onto a north-south crossplot) 5S 1S 15S 2S 25S 3S 35S 25 mi. North desorption gas CBM production gas TOWNSHIP 16 BTU/scf 1% methane 95 BTU/scf 9% methane Douglas, Shawnee Lansing, Kansas City, Pleasanton Cherokee, Marmaton desorption gas (Nebraska) (Oklahoma)

6 Helium content for eastern KS Pennsylvanian gases (projected onto a north-south crossplot) 2. % Helium desorption gas (Bostic et al., 1993) desorption gas production gas 5S 1S 15S 2S 25S 3S 35S 25 mi. North TOWNSHIP Douglas, Shawnee Lansing, Kansas City, Pleasanton Cherokee, Marmaton desorption gas (Nebraska) (Oklahoma)

7 COAL RANK (color-coded to coal rank) Cherokee & Marmaton Gps. APPROXIMATE RANK VITRINITE. REFLECT. (R o %) HEATING VALUE (BTU/lb) (dry, ash-free) lignite A increasing rank subbituminous high-volatile bituminous A C B C B A ,3 9,5 1,5 11,5 13, 14, 14,25 15, 1.11 medium-volatile bituminous

8 ft T max for Pennsylvanian strata (Forest City basin) average T max ( ) and range ( ) oil window for Tmax

9 T max maturity for eastern KS strata (projected onto a north-south crossplot) Douglas, Shawnee Depth (ft) S 25 mi. North oil window 1S 15S 2S 25S 3S 35S TOWNSHIP Lansing, Kansas City, Pleasanton Cherokee, Marmaton Rock-Eval T max (Nebraska) (Oklahoma) from Hatch et al., 1989 Barker et al., 1992 Hatch and Newell, 1999

10 VITRINITE REFLECTANCE (color-coded to coal rank) Cherokee & Marmaton Gps. APPROXIMATE RANK VITRINITE. REFLECT. (R o %) HEATING VALUE (BTU/lb) (dry, ash-free) lignite A increasing rank subbituminous high-volatile bituminous A C B C B A ,3 9,5 1,5 11,5 13, 14, 14,25 15, 1.11 medium-volatile bituminous after Newell (1997)

11 STABLE ISOTOPES (R x -R std ) δ(x) = * 1 (R std ) where R x is the isotopic ratio of the heavy, rare isotope versus the light, abundant isotope of the sample (i.e., 13 C/ 12 C, or deuterium / hydrogen) vs. that of the standard (R std ) usually reported in parts per mil ( ) if R x < R std, then δ(x) is negative if R x > R std, then δ(x) is positive EXAMPLE: if a methane has a δ( 13 C) of -65, then it is isotopically lighter than another methane that has a δ( 13 C) of -4

12 δd METHANE ( ) EXAMPLE: if a methane has a δ( 13 C) of -58, then it is isotopically "lighter" in carbon than another methane that has a δ( 13 C) of if a methane has a δ(d) of -23, then it is isotopically "lighter" in hydrogen -24 than another methane that has a δ(d) of δ13c METHANE ( )

13 1 WETNESS (%) L'worth Co. (Riverton) mixing Pomona Pomona McLouth NW THERMOGENIC GAS L'worth Co. (Mineral) L'worth Co. (Riverton) maturation δd METHANE ( ) MICROBIAL GAS? MICROBIAL GAS???? Cass Co. (Tebo & Neutral) MIXED GAS Montgomery Co. (Croweburg) maturation? δ 13 C METHANE ( ) SOURCE ROCK MATURITY (Ro %) THERMOGENIC GAS eastern KS conventional gas (from Jenden et al., 1988) coalbed desorption gas (Leavenworth Co. data from Bostic et al., 1993)

14 MICROBIAL GAS BY: CO 2 reduction CO 2 + 4H 2 CH 4 + 2H 2 O * CO 2 present is dominantly as HCO 3 dissolved in formation waters * methanogenic bacteria preferentially reduce 12 CO 2, so 13 C-enriched CO 2 and 12 C-enriched CH 4 results * microbes do not produce higher-molecular-weight hydrocarbons other than methane acetate fermentation CH 3 COOH CH 4 + CO 2 methyl group reduction by dissimilation of acetate CH 3 COO - + H + CH 4 + CO 2 * δd more negative than -3 * surrounding water provides only 1 of the 4 hydrogen atoms incorporated in methane

15 oil oil & gas gas GEOGRAPHIC DISTRIBUTION of ISOTOPIC ANALYSES of GASES AGE U. PENN NAME OF FIELD Mill Creek, Schrader OIL & GAS FIELDS N 25 mi M. PENN MSSP Silver City, Thayer, Brewster, Elk City, Mapleton NE, Neosho Falls, Olathe, Clinesmith, Easton, McLouth NW, Pomona, Sallyards, Welch-Mohr Kingston, Brewster, Irish Valley, Neosho Falls, Paola-Rantoul, Tucker. Cass Co. L. ORD Logsden eastern KS conventional gas (from Jenden et al., 1988) coalbed desorption gas GREEN = BIOGENIC BLUE = MIXED MAROON = THERMOGENIC Montgomery Co.

16 . Methane Carbon Isotope vs. Depth (subsurface) Cherokee Basin and Forest City Basin -7 δ 13 C METHANE ( ) Depth (feet) CONVENTIONAL GAS Douglas, Shawnee Gps. Lansing, Kansas City, Pleasanton Gps. Cherokee, Marmaton Gps. Mississippian, sub-mississippian CBM GAS Leavenworth Co. Cass Co. Montgomery Co. 25 3

17 Wetness of Gas vs. Depth (subsurface) Cherokee Basin and Forest City Basin Wetness (%) Depth (feet) CONVENTIONAL GAS ANALYSES Douglas, Shawnee Gps. Lansing, Kansas City, Pleasanton Gps. Cherokee, Marmaton Gps. Mississippian, sub-mississippian CBM GAS ANALYSES Leavenworth Co. Cass Co. Montgomery Co. }undiff. 2 25

18 oil oil & gas gas GEOGRAPHIC DISTRIBUTION of ISOTOPIC ANALYSES of GASES AGE U. PENN NAME OF FIELD Mill Creek, Schrader OIL & GAS FIELDS N 25 mi M. PENN MSSP Silver City, Thayer, Brewster, Elk City, Mapleton NE, Neosho Falls, Olathe, Clinesmith, Easton, McLouth NW, Pomona, Sallyards, Welch-Mohr Kingston, Brewster, Irish Valley, Neosho Falls, Paola-Rantoul, Tucker. Cass Co. L. ORD Logsden eastern KS conventional gas (from Jenden et al., 1988) coalbed desorption gas GREEN = BIOGENIC BLUE = MIXED MAROON = THERMOGENIC Montgomery Co.

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21 oil oil & gas gas GEOGRAPHIC DISTRIBUTION of ISOTOPIC ANALYSES of GASES AGE U. PENN NAME OF FIELD Mill Creek, Schrader OIL & GAS FIELDS N 25 mi M. PENN MSSP Silver City, Thayer, Brewster, Elk City, Mapleton NE, Neosho Falls, Olathe, Clinesmith, Easton, McLouth NW, Pomona, Sallyards, Welch-Mohr Kingston, Brewster, Irish Valley, Neosho Falls, Paola-Rantoul, Tucker. Cass Co. L. ORD Logsden eastern KS conventional gas (from Jenden et al., 1988) coalbed desorption gas GREEN = BIOGENIC BLUE = MIXED MAROON = THERMOGENIC Montgomery Co.

22 oil oil & gas gas GENERALIZED REPRESENTATION of a TRANSITION ZONE in CAMBRIAN-ORDOVICIAN ARBUCKLE GP. WATERS (from Macfarlane and Hathaway, 1987) OIL & GAS FIELDS N 25 mi brine transition 2,5 mg/l isochore eastern KS conventional gas (from Jenden et al., 1988) coalbed desorption gas GREEN = BIOGENIC BLUE = MIXED MAROON = THERMOGENIC brine?? transition fresh

23 CONCLUSIONS maturation increases southward in Forest City and Cherokee basins gas content likely increases southward also, perhaps westward into th some coalbed gases have biogenic component biogenesis more important in updip areas separate thermogenic and biogenic production fairways are possible

24 Regional Trends in Coalbed Gas Composition and Thermal Maturation in Eastern Kansas: Implications for Predicting Quality and Location of Coalbed Gas K. David Newell and L. Michael Magnuson Kansas Geological Survey, University of Kansas, Lawrence, KS