Hydrate Formation and Gas Production from Hydrates by CO 2 Injection - PowerPoint PPT Presentation

U N I V E R S I T Y O F B E R G E N Institute of Physics and Technology Hydrate Formation and Gas Production from Hydrates by CO 2 Injection By Lars Petter Øren Hauge uib.no

Institute of Physics and Technology Natural gas hydrate • Crystalized structure consisting of water and a guest molecule (e.g. methane) – resembles ice • High pressure (>30 bar) and low temperature (<10 °C) • Permafrost regions and off-shore Ota et al. (2005) uib.no

Institute of Physics and Technology Estimates of Total Gas Hydrate Amount Most confident estimate by Claudia and Sandler 2005 Proven Crude Oil 2010 estimate by EIA (1358 BBOe) uib.no

Institute of Physics and Technology Hydrate Reservoir strategies • Production scenarios • Pressure reduction • Temperature increase • Chemical additive • Exchange with CO 2 uib.no

Institute of Physics and Technology Hydrate Injection of CO 2 to produce methane Pros Cons • Integrity of hydrate • Requires permeability structure remains intact • Risk of hydrate formation • Sequestration of CO 2 from free water • No temperature increase • Relatively slow rate of exchange • Increased stability • Investment cost uib.no

Institute of Physics and Technology Experimental set up Pressure regulator Flow control valve Back pressure valve MFM Bypass valve GC High pressure pumps 1/8’’ Pressure Gas supply tubing transducer Sandstone core Safety ISCO pump pressure valve Thermocouple Cooling jacket/bath Refrigerator bath Confinement buffer Circulating antifreeze Model made by Christian Hågenvik uib.no

Institute of Physics and Technology Experimental conditions • Porous media – Bentheim sandstone – High permeable (1.1 D) – 20-25% porosity – Homogeneous (99% quartz) • Brine saturation 0.4 – 0.7 • Brine salinity 0.1 – 3.5 wt% NaCl • Pressurized with CH 4 to 83 barg/1200 psi • Temperature reduced from ~23 °C to 4 °C uib.no

Institute of Physics and Technology Methane Hydrate formation EXPERIMENTAL RESULTS uib.no

Institute of Physics and Technology Same initial conditions (system not dissasembled, only reformed) uib.no

Institute of Physics and Technology Hydrate formation uib.no

Institute of Physics and Technology Water saturation based on mass balance and resistivity uib.no

Institute of Physics and Technology Post Hydrate formation Limiting factor: lack Limiting factor: Mass transport – water trapping of water uib.no

Institute of Physics and Technology Post Hydrate formation Higher hydrate saturation for Swi ≈ 0.6 Limiting factor: lack Limiting factor: Mass transport – water trapping of water uib.no

Institute of Physics and Technology CO 2 induced methane production EXPERIMENTAL RESULTS uib.no

Institute of Physics and Technology Experimental procedure • A back pressure valve maintains constant production pressure of approximately 85 barg. • CO 2 , or a CO 2 /N 2 mix, is injected at a constant flow rate of 1.2 ml/h for all experiments. • Injection pressure, production pressure, gas fraction and mass produced is monitored and later used to calculate differential pressure and fluids produced. uib.no

Institute of Physics and Technology Fraction of Methane during Production Measured by GC uib.no

Institute of Physics and Technology Production during CO 2 injection Resistivity, gas produced and differential pressure Pressure build up uib.no

Institute of Physics and Technology Remediation of plugged core by use of N 2 Second CO2 injection Inital CO2 injection N2 pressure buildup uib.no

Institute of Physics and Technology CO-injection of CO 2 and N 2 (25/75 mol% resp.) N2 pressure Co-injection of Injection of buildup CO2 and N2 pure CO2 uib.no

Institute of Physics and Technology CO-injection of CO 2 and N 2 (25/75 mol% resp.) Pure CO 2 injection starts Injected N 2 fraction Injected CO 2 fraction uib.no

Institute of Physics and Technology Methane recovery Free gas in porous media included uib.no

Institute of Physics and Technology