################################################################################ MODELLING THE BRITTLE-DUCTILE TRANSITION. PROBLEM 3A -------------------------------------------------------------------------------- Last update on 22.02.2020 Program Version: 2019.B01 We simulate the problem using the BINMIXT module with CO2-H2O equation of state. The concentration of CO2 is set to 0. Thus it does not influence the simulation results. A small CO2 concentration can be specified in order to track the fluid. ################################################################################ RUNSPEC ################### RUNSPEC section begins here ###################### In this section, the general options and parameters of the simulation are specified. We enable HCROCK - heat conduction DUCTILE - ductile behavior of rocks DYNFRACK - hydrofracturing METRIC ^^^^^^^^^^^^^^^^^^^^^ We use METRIC units ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST We use FAST option. GRID ##################### GRID section begins here ####################### In this section, we must define the geometrical and logical structures of the reservoir (computational grid, boundaries, faults, wells, point sources, etc.). The grid is specified within brackets MAKE-ENDMAKE MAKE <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< -- cartesian We select Cartesian gridding -- grid nx ny nz option and specify the number of CART 72 1 24 / grid blocks along every axis. The grid is 72*1*24 blocks. If better resolution is needed then increase the number of grid blocks to e.g. 150*1*50. XYZBOUND -- xmin-xmax ymin-ymax zmin-zmax We specify the domain extent in meters. -18000 18000 -0.5 0.5 0 12000 / The domain width is 36000 meters and its depth is 12000 meters. BOUNDARY We create the auxiliary blocks for 2 6* 'K-' 5* INFTHIN 4* 1 2 / - the top boundary (with FLUXNUM=2); 3 6* 'K+' 5* INFTHIN 4* 1 2 / - the bottom boundary (with FLUXNUM=3). / Parameters in all these blocks are constant over time (ACTNUM=2). SRCSPECG We place the point source at MAGMA 3* 0.0 0.0 10000 / x=0km, y=0km, z=10km. The source name / is MAGMA. ENDMAKE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> REGALL ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The following operations are applied to all grid blocks including the auxiliary blocks created with the BOUNDARY keyword. OPERAREG -- -------- -------- -------- -------- -------- -------- -------- -------- PORO DEPTH SATNUM 1 CRUSTPOR -0.65 -0.1 0.0019 / PERMX DEPTH 2* CRUSTPER 1.0 3.2 1000 / HCONDCFX 1* 2* EQUALS 2.8 / PRESFAIL DEPTH 2* MULTA 2 0.11 / PRESLITH DEPTH 2* MULTA 2 0.27 / -- -------- -------- -------- -------- -------- -------- -------- -------- / We specify: 1. PORO=10^(-0.65-0.1*DEPTH/1000+0.0019*(DEPTH/1000)^2) (see DOI: 10.1134/S1069351314040181) 2. lg(PERMX)=min(1.0-3.2*lg(DEPTH/1000),1000) (see DOI: 10.1029/97JB00552) 3. We equate heat conductivity (HCONDCFX) to 2.8 W/m/K 4. PRESFAIL=2+0.11*DEPTH (failure pressure) 5. PRESLITH=2+0.27*DEPTH (lithostatic pressure) COPYREG -- -------- -------- -------- -------- We copy in all grid blocks PERMX PERMZ TYPENUM 1 / - PERMX to PERMZ HCONDCFX HCONDCFZ SATNUM 1 / - HCONDCFX to HCONDCFZ -- -------- -------- -------- -------- / OPERAREG -- -------- -------- -------- -------- -------- -------- -------- -------- PERMXFR PERMX TYPENUM 1 COPY / PERMXFR 1* 2* MULTIPLY 5 / PERMZFR PERMXFR 2* COPY / -- -------- -------- -------- -------- -------- -------- -------- -------- / We specify in all permeable grid blocks (TYPENUM=1): 1. PERMXFR=5*PERMX 2. PERMZFR=PERMXFR i.e. maximum fractures permeability is 5 times the matrix permeability. RPTGRID DEPTH PORO PERMX PERMZ HCONDCFX HCONDCFZ PRESFAIL PRESLITH PERMXFR PERMZFR / We report these parameters from the GRID section. The parameters are saved in BDT-PROBLEM-3A.GRID.SUM and BDT-PROBLEM-3A.GRID.vtu. PROPS ##################### PROPS section begins here ###################### In this section, we must define the thermophysical properties of the fluid, host rock as well as the relative permeability curves. Rock properties are specified within brackets ROCK-ENDROCK ROCK <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< / ROCKDH We specify that 2700 1.0 / - rock density is 2700 kg/m3 - rock heat capacity is 1.0 kJ/kg/K. DUCTTAB -- ---------- ---------- ---------- ---------- -- T units Temp_b Temp_d -- ---------- ---------- ---------- ---------- C 360 430 500 / <<< temperature T -- ---------- ---------- ---------- ---------- (degree C) 0.0 0.5 1.0 / <<< eta(T) function -- ---------- ---------- ---------- ---------- -- -log(D) -log(D) -log(D) -- lambda at 360 C at 430 C at 500 C -- ---------- ---------- ---------- ---------- 1.0 0.0000 0.0000 0.0000 / 0.9 0.0000 0.8622 1.7245 / 0.8 0.0000 1.5918 3.1837 / 0.7 0.0000 2.1888 4.3776 / 0.6 0.0000 2.6531 5.3061 / 0.5 0.0000 2.9847 5.9694 / <<< log(D) as function of 0.4 0.0000 3.1837 6.3673 / <<< lambda and T. 0.3 0.0000 3.2500 6.5000 / 0.2 0.0000 3.2500 6.5000 / 0.1 0.0000 3.2500 6.5000 / 0.0 0.0000 3.2500 6.5000 / -- ---------- ---------- ---------- ---------- / With the DUCTTAB keyword we specify parameters of the rocks creep, i.e. functions eta(T) and D(lambda,T). The transition from brittle to ductile behavior begins at TempB=360 C. eta(T)=0 if T<360 C and eta(T)=1 if T>500 C. DYNFRTAB -- pore-fluid fractures -- factor (lambda) productivity (F) 0.5 -0.00025 / 0.6 -0.00016 / 0.7 -0.00009 / 0.8 -0.00004 / 0.9 -0.00001 / 0.99 -0.0000001 / 1.0 0.00000 / 1.01 0.0000001 / 1.1 0.00001 / 1.2 0.00004 / 1.3 0.00009 / 1.4 0.00016 / 1.5 0.00025 / / With the DYNFRTAB keyword we specify parameters of the hydrofracturing, i.e. the function F(lambda). ENDROCK >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LOADEOS '../../INCLUDE/CO2H2O_V3.0.EOS' / We load the CO2-H2O mixture properties file. The relative permeabilities are specified within brackets SAT-ENDSAT SAT <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< / SATTAB -- swat krwat krvap 0.0 0.0 1.0 / The relative permeability for water and 1.0 1.0 0.0 / vapor are specified here. They do not / influence the simulation results because phase partitioning does not occur. ENDSAT >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> INIT ####################### INIT section begins here ##################### In this section, we must define the initial and boundary conditions. We must define the required number of parameters for every cell associated with the simulation. REGALL ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The following operations are applied to all grid blocks including the auxiliary blocks created with the BOUNDARY keyword. OPERAREG -- This is applied to all grid blocks. -- -------- -------- -------- -------- -------- -------- -------- -------- PRESSURE DEPTH SATNUM 1 MULTA 1 0.27 / TEMPC DEPTH SATNUM 1 MULTA 20 0.055 / COMP1T 1* 2* EQUALS 0 / -- -------- -------- -------- -------- -------- -------- -------- -------- / We specify: 1. PRESSURE=1+0.27*DEPTH (Initial pressure is 1 bar less than the lithostatic pressure. The pressure of 1 bar is maintained at the top boundary.) 2. TEMPC=20+0.055*TEMPC (We impose linear distribution of temperature vs depth. Initial temperature gradient is 5.5 C per 100 m and temperature of 20C is maintained at the top boundary.) 3. COMP1T=0 (CO2 concentration is 0.) OPERAREG -- -------- -------- -------- -------- -------- -------- -------- -------- PRES 1* FLUXNUM 3 ADD -75 / -- -------- -------- -------- -------- -------- -------- -------- -------- / We reduce the pressure at the bottom boundary by 75 bar. This pressure is maintained at the bottom boundary. EQUALNAM -- -------- -------- -------- PRES 3000 MAGMA / We specify the temperature of injected TEMPC 680 / fluid is 680C at 3000 bar. In order to COMP1T 1E-6 / track the fluid we specify a small -- -------- -------- -------- concentration of CO2. / RPTSUM DEPTH DENT PRES TEMPC DCTTMULT PFLDFACT FLUXI#T FLUXK#T PHST COMP1T PRESLITH PRESFAIL PRESFDYN TRANMULT TRANFRMT / We specify the properties which are saved at every report time (in the files BDT-PROBLEM-3A.####.SUM (.vtu)). SCHEDULE #################### SCHEDULE section begins here #################### REPORTS NOTHING / No reports to the LOG-file. <<<<<<<<<<<<<<<<<<<<<<<< These are numerical algorithm setups <<<<<<<<<<<<<<<<<<< VARS -- -------- -------- -------- We specify that in every simulation cell PRES MAXV 3500 / - maximum pressure is 3500 bar; PRES DMAX 500 / - maximum pressure change is 500 bar; TEMP MAXV 1373.15 / - maximum temperature is 1373.15 K; TEMP DMAX 100 / - maximum temperature change is 100 K. -- -------- -------- -------- (The change is in one iteration of the / Newton method). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> TUNING We specify that the maximum time step 1* 10000 2*0.0001 / is 10000 days. TSTEP We advance simulation to t=30000 years. 3*3652500 / TUNING We increase the maximum time step to 1* 100000 / 100000 days. TSTEP We advance simulation to t=250000 years 22*3652500 / reporting simulation data every 10000 years. SRCINJE MAGMA MASS 1* 3500 1* 1 1000 10 / Here injection begins. The injection / rate is 1 ton/day with the pressure threshold of 3500 bars that is actually not reached in the simulation. TUNING We increase the maximum time step to 1* 2500 1 / 2500 days. TSTEP We advance simulation to t=275000 years 25*365250 / reporting simulation data every 1000 years. POST ####################### POST section begins here ##################### CONVERT We convert the output to ParaView compatible format. END #######################################################################