Petrophysical Signatures of the Liquid-Steam Phase Transition in - - PowerPoint PPT Presentation

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Jun 25, 2023 48 likes •88 views

Petrophysical Signatures of the Liquid-Steam Phase Transition in Geothermal Reservoir Rocks BRUHN, David; MILSCH, Harald; SPANGENBERG, Erik GFZ Potsdam, Germany FLVENZ, lafur; KRISTINSDTTIR, Lney Halla; Icelandic Geosurvey (SOR),

SLIDE 1

Petrophysical Signatures of the Liquid-Steam Phase Transition in Geothermal Reservoir Rocks

BRUHN, David; MILSCH, Harald; SPANGENBERG, Erik GFZ Potsdam, Germany FLÓVENZ, Ólafur; KRISTINSDÓTTIR, Líney Halla; Icelandic Geosurvey (ÍSOR), Reykjavík, Iceland JAYA, Makky Freie Universität Berlin, Germany.

SLIDE 2

Sample characterisation

Sample 3A 58 Ftbl Rock type Hyaloclastite Basalt Sandstone Origin/Well no. Ölkelduháls ÖJ-1 Krafla KH-1 Fontainebleau Depth (m) 795 187

Porosity (%)

20.7 20 7.5 Density (g/cm3) 2.15 2.37 2.45 Fluid conductivity (mS/cm) 0.81 0.78 10.8 Pore pressure (bar) 80 19 50

Conf. Pressure (bar)

175 50 100

SLIDE 3

The apparatus

1 & 5: Downstream and upstream pumps (Pmax: 50 MPa, flow rate: <15 l/h) 2: Reservoir for chemical fluid analysis 3: Pressure vessel and heater (Pmax: 140 MPa, Tmax.: 250C) 4: Confining pressure pump (Pmax: 140 MPa oil) 6: Fluid reservoir (10 l)

SLIDE 4

The liquid-steam transition

Sample 58 4 8 12 16 20 500 1000 1500 time (min.) pore pressure (bar) 0,5 0,6 0,7 0,8 0,9 1

conductivity (mS/cm) Sample 58 5 10 15 20 500 1000 1500 time (min.) pore pressure (bar) 10 12,5 15 17,5 20 pump volume (cm3)

0,1 0,2 0,3 0,4 0,5 0,6 50 100 150 200 250 300 350 Time [hours] Conductivity [mS/cm]

20 40 60 Pore pressure [bar]

Release of pore fluid reduces pore pressure => vaporisation Conductivity decreases gradually

Pore pressure cycling in sandstone