Use of Gas Phase Tracers for Monitoring CO 2 Injection at the Frio Test Site

Transcription

1 Use of Gas Phase Tracers for Monioring CO 2 Injecion a he Frio Tes Sie GCCC Digial Publicaion Series #05-04r K. Pruess B. Freifeld M. Kennedy C. Oldenburg T. J. Phelps M. C. van Soes Keywords: Gas Phase Tracers, Phase-Pariioning Tracers, Brine Displacemen, Reardaion Facor, Tracer Travel Time Cied as: Pruess, K., Freifield, B., Kennedy, M., Oldenburg, C., Phelps, T.J., and van Soes, M.C., Use of gas phase racers for monioring CO2 injecion a he Frio Tes Sie: presened a he Naional Energy Technology Laboraory Fourh Annual Conference on Carbon Capure and Sequesraion, Alexandria, Virginia, May 2-5, GCCC Digial Publicaion Series #05-04r, pp

2 Use of Gas Phase Tracers for Monioring CO 2 Injecion a he Frio Tes Sie Karsen Pruess 1, Barry Freifeld 1, Mack Kennedy 1, Cur Oldenburg 1, Tommy J. Phelps 2 and M.C. van Soes 1 1 Earh Sciences Division, Lawrence Berkeley Naional Laboraory 2 Oak Ridge Naional Laboraory Fourh Annual Conference on Carbon Capure and Sequesraion Alexandria, VA, May 2 5, 2005

3 Ouline Phase-pariioning racers Issues for CO 2 injecion ino brine aquifers Tracer migraion and analysis Tes design Resuls Concluding Remarks

4 Phase-Pariioning Tracers (I) Chemical species ha are boh waer soluble and volaile non-condensible gases (O 2, CO 2, CH 4 ) noble gases SF 6 ; volaile organic chemicals (e.g., halogenaed hydrocarbons) Henry s law racer P gas CO 2 Tracer Brine racer = K h x aq deermine reservoir processes and condiions (phase sauraions, boiling, fracure-marix ineracion) find fas preferenial flow pahs

5 Phase-Pariioning Tracers (II) Typical applicaion is for muliphase sysems, wih one mobile and one or more immobile fluid phases. Tracer migraion is rearded (slowed) relaive o an iner (insoluble) racer by pariioning ino immobile phases. The raio of ravel imes is he reardaion facor, R = PPT / iner. R is given by he (local) raio of oal racer invenory o racer invenory in he mobile phase. From known phase pariioning behavior (solubiliy, volailiy), observaions of racer reardaion can be used o infer he average volume fracions of differen fluid phases along he flow pah. Applicaions of phase-pariioning racers have been made for differen purposes, including: deerminaion of residual oil in peroleum reservoirs esimaion of non-aqueous phase liquid (NAPL) conaminaion characerizaion of rapped gas in groundwaer sysems deerminaion of boiling processes in geohermal reservoirs

6 Displacemen of Brine by CO 2 (I) CO2 CO2 sauraion CO2 R R uniform displacemen (Buckley-Levere) graviy override

7 Displacemen of Brine by CO 2 (II) CO2 R non-uniform sweep formaion heerogeneiy hydrodynamic insabiliies

8 Issues in Displacemen of Brine by CO 2 how does CO 2 invade and occupy he pore space? where does he CO 2 go, and how much brine is lef behind? geomery of he displacemen process uilizaion of subsurface space available sorage capaciy

9 Gas Tracers Tracer ranspor in single-phase gas condiions φc g = divc g vg + divφτd g Cg wih φ = porosiy = racer concenraion in gas (parial densiy; kg/m 3 ) C g v g = gas velociy τ = oruosiy D g = racer diffusiviy Tracer ranspor in wo-phase condiions wih immobile liquid φ S g C g + S a C [ a ] = div C g vg +div φτ g D g Cg R is he reardaion facor, given by R = S g C g + S a C [ a ] = 1 + S a ζ S g C g 1 S a = φr S g C g wih ζ = C a C g an aqueous-gas disribuion coefficien (solubiliy)

10 Reardaion Facor From a known (observed) reardaion facor, aqueous phase sauraion can be calculaed: R S a = 1 R 1 + ζ R is he raio of racer ransi (or ravel) ime for a phase-pariioning racer o ha for a hypoheical insoluble racer i R = i all racers are soluble o some exen, so i is no observable, and neiher is R from wo differen phase-pariioning racers and u, obain and u hen have wo equaions for he unknowns i and S a eliminaing i gives aqueous phase sauraion as S a = 1 u 1 u + ζ u u ζ

11 Advanages of Noble Gas Tracers no significan subsurface sinks or sources chemically iner, non-hazardous abundance can be measured wih grea precision Henry s coefficien as funcion of emperaure Henry s law: P = K H x Helium Neon Argon lines: Croveo e al. (1982) symbols: Smih (1986) He Ne Kr Xe Isoope Parial pressure in air, Pa Dissolved mass fracion in waer a T = 10 deg-c Henry s coefficien, Pa T = 10 deg-c T = 65 deg-c 22Ne e e e Ar e e e9 84Kr e e e9 2 Krypon 132 Xe 2.370e e e e Xenon Daa from Croveo e al., 1982 Temperaure (ÞC) T = 65 deg-c

12 Field Equipmen for Gas Tracer Tess Gas samples colleced using he U-Tube sampling sysem Gas-phase was sampled off op of high pressure sample cylinders Sample gas processed in realime using quadrupole mass specromeer Complee collecion and analysis cycle occurred every 11 minues once sample sream became self-lifing

13 Gas Tracer Observaions Componen Mass Injeced Injecion Time (Rel. ime hr.) CO 2 3 kg/s * 4 Oc 11:34 ( / - 2.0) PMCH, PTCH 3.1 kg 4 Oc 13:26 (1.87) PMCP, PDCH 0.3 kg 8 Oc 18:19 (102.75) PMCH, 0.3 kg 9 Oc 11:37 PTCH (120.05) SF 6 < 200g 9 Oc 11:37 (120.05) Kr 83.8 g 9 Oc 12:39 (121.08) Injecion Duraion (hr) Arrival Time (Rel. ime hr.) N/A 6 Oc 14: / Oc 14: / Oc 15:32 (147.97±0.5) Oc 11:42 (168.13±0.5) Oc 10:26 (166.87±0.5) Oc 10:37 (167.05±0.5) Peak Time (Rel. ime hr.) Travel ime (hr.) N/A / Oc 15:20 (51.8±0.9) 10 Oc 22:52 (155.3±0.5) 11 Oc 18:36 (175.03±0.5) 11 Oc 18:22 (174.80±0.5) 11 Oc 20:01 (176.45±0.5) 48.0± ± ± ± ±0.5

14 Observed Tracer Breakhrough Curves SF 6 : SF6 = hr ± 1 % Shifed Time Plo of SF6 & Kr SF6 C/Cmax Kr C/Cmax PFT C/Cmax Kr: Kr = hr ± 1 % Time shif from iniial injecion: PFT 30 min Kr 66 min SF6 17 min All imes shifed o correc for mean injecion ime. C/Cmax /10/04 0:00 10/11/04 0:00 10/12/04 0:00 10/13/04 0:00

15 Analysis S a = 1 u 1 u + ζ u u ζ SF6 / Kr = 52.63/53.47 = ± 1 % racer Solubiliies a T = 65 deg-c brine* molaliy Henry's coefficien (Pa) solubiliy ζ Kr e e e e-2 SF e e-3 Inferred aqueous phase sauraions (differen assumpions for solubiliies) Kr SF 6 S a 1.55 m brine pure waer 45.2 % 1.55 m brine insoluble 40.0 % pure waer pure waer 31.8 % * modeled as pure NaCl

16 Uncerainy in Breakhrough Time SF6 / Kr = ± 1 %; range: assume 1.55 m NaCl brine for Kr solubiliy; SF 6 insoluble SF6 / Kr = 0.975; ==> S a = 51.2 % SF6 / Kr = 0.993; ==> S a = 22.4 % ===> small uncerainy in relaive racer arrival imes ranslaes ino large uncerainy for aqueous phase sauraion

17 Concluding Remarks Conduced successful gas racer ess a Frio sie. More waer-soluble racer (krypon) is rearded relaive o less soluble SF 6. From krypon reardaion relaive o SF 6, esimae in siu waer sauraion in CO 2 plume of approximaely 40 %. Inerpreaion (concepual model) is no unique: analysis assumes simples model: phase-pariioning according o local equilibrium how abou non-equilibrium dissoluion and subsequen diffusion in aqueous phase? pariioning ino addiional phases? (oil phase, sorpion on solids) Ambiguiies may be reduced by using several differen racers Addiional daa analysis is underway.

18 Deermining Tracer Travel Time SF6 C/Cmax Krypon C/Cmax PFT C/Cmax C/Cmax Measured Concenraion SF hr Oc Oc Oc Oc-04 Kr hr Daa Time Correced 0.5 and Peak Fi wih a Third Order Polynomial 0 C/Cmax SF6 C/Cmax Kr C/Cmax Poly. (Kr C/Cmax) Poly. (SF6 C/Cmax) Time (hours)