`CO2SOL`

Recognised by the OPM Flow parserRUNSPEC

The CO2SOL keyword activates dissolved carbon dioxide (CO2) in the water phase, where CO2 is represented by the SOLVENT pseudo component, using the simulator’s CO2-Brine PVT model. This keyword is a compositional keyword in the commercial simulator but has been implemented in OPM Flow’s black-oil model.

The CO2SOL keyword can be used when modelling CO2 injection in depleted hydrocarbon reservoirs. See also the CO2STORE keyword in the RUNSPEC section which can be used when modelling CO2 injection in saline aquifers.

The CO2-Brine PVT model computes the PVT properties such as density, viscosity, and enthalpy internally as functions of pressure, temperature, and composition by using analytic correlations and models from the literature rather than by interpolation of tabulated values in the input deck. These values are transformed to the standard black-oil equivalent PVT tables internally by the simulator. A full description of the underlying PVT models is described by Sandve et al.1 Tor Harald Sandve1, Sarah E. Gasda, Atgeirr Rasmussen, and Alf Birger Rustad. Convective dissolution in field scale CO2 storage simulation using the OPM Flow simulator. Submitted to TCCS 11 – Trondheim Conference on CO2 Capture, Transport and Storage Trondheim, Norway – June 21-23, 2021.. Note that the CO2-Brine PVT properties depend on the temperature and salinity and these must therefore be entered in the PROPS section. The reservoir temperature can be defined using, e.g., the RTEMP keyword. Region based salinity can be provided using the SALINITY keyword.

Tor Harald Sandve1, Sarah E. Gasda, Atgeirr Rasmussen, and Alf Birger Rustad. Convective dissolution in field scale CO2 storage simulation using the OPM Flow simulator. Submitted to TCCS 11 – Trondheim Conference on CO2 Capture, Transport and Storage Trondheim, Norway – June 21-23, 2021.

The CO2SOL keyword must be used together with the SOLVENT keyword in the RUNSPEC section. The SOLVENT keyword activates the four component black-oil model: oil, water and gas, plus a solvent (in this case CO2).

The DISGASW keyword in the RUNSPEC section can be used to model dissolution of CO2 in the Brine. Note that hydrocarbon gas is not allowed to dissolve in the Brine (this is considered a reasonable assumption for most hydrocarbon gases).

The hydrocarbon reservoir fluid properties should be set up as normal apart from the water PVT properties, which will be defined by the simulators’ CO2-Brine PVT model, so the water PVT keywords (e.g. PVTW) are not required. The CO2 PVT properties will also be defined by the CO2-Brine PVT model so the solvent PVT keywords (e.g. SDENSITY, PVTSOL) are also not required.

The oil-water and gas-water saturation functions should be set up as normal. The CO2 and gas miscible relative permeability tables should be defined using the SSFN keyword in the PROPS section.

The initial CO2 saturations in the model can be specified by enumeration using the SSOL keyword in the SOLUTION section.

The CO2 fraction in a well’s injection stream can be defined using the WSOLVENT keyword in the SCHEDULE section.

There is no data required for this keyword and there is no terminating “/” for this keyword.

Records: No records — the keyword stands alone

Example

The example shows the usage of CO2SOL to model CO2 injection in a live-oil reservoir. The RUNSPEC section includes the CO2SOL keyword, which activates dissolved carbon dioxide (CO2) in the water phase. The SOLVENT keyword activates the solvent pseudo component, which represents CO2. The DISGASW keyword has been used to activate dissolved CO2 in the brine.
-- ==============================================================================
--
-- RUNSPEC SECTION
--
-- ==============================================================================
RUNSPEC
-- ------------------------------------------------------------------------------
-- FLUID TYPES AND TRACER OPTIONS
-- ------------------------------------------------------------------------------
--
-- ACTIVATE DISSOLVED CO2 IN WATER (OPM FLOW KEYWORD)
--
CO2SOL
--
-- SOLVENT PHASE IS PRESENT IN THE RUN
--
SOLVENT
--
-- DISSOLVED CO2 IN WATER IS PRESENT IN THE RUN (OPM FLOW KEYWORD)
--
DISGASW
The second part of the example covers the additional data required in the PROPS section, in which the CO2-gas miscible relative permeabilities are defined using the SSFN keyword. The initial temperature and salinity are defined using the RTEMP and SALINITY keywords. The oil and gas PVT properties should be defined in the normal way. No water PVT data is required.
-- ==============================================================================
--
-- PROPS SECTION
--
-- ==============================================================================
PROPS
--
-- RESERVOIR
-- TEMPERATURE
-- -----------
RTEMP
80.0 / RESERVOIR TEMP
--
-- SET SALINITY FOR ALL CELLS (OPM FLOW KEYWORD)
--
SALINITY
0.7 /
--
-- SOLVENT RELATIVE PERMEABILITY TABLES
--
SSFN
-- SGAS KRGT KRST
-- FRAC
-- -------- -------- --------
0.0000 0.0000 0.0000
1.0000 1.0000 1.0000 /
The third part of the example covers initialising the model in the SOLUTION section. Here the EQUIL keyword is used as normal to equilibrate the oil, gas and water phases, and the SSOL keyword to specify that there is initially no CO2 present in the gas phase.
-- ==============================================================================
--
-- SOLUTION SECTION
--
-- ==============================================================================
SOLUTION
--
-- DATUM DATUM OWC PCOW GOC PCGO RS RV N E300 RVW
-- DEPTH PRESS DEPTH ---- DEPTH ---- OPT OPT OPT OPT OPT
EQUIL
2000.0 200.0 1900.0 0.00 2000.0 0.00 1* 1* 1* 2* 1* /
--
-- DEFINE INITIAL EQUILIBRATION SOLVENT SAT VALUES FOR ALL CELLS IN THE MODEL
-- BASED ON NX = 100, NY = 100 AND NZ = 3
--
SSOL
30000*0.0 /
For the summary section, the CO2 storage quantity can be tracked using the solvent injection and production volumes as shown below.
-- ==============================================================================
--
-- SUMMARY SECTION
--
-- ==============================================================================
SUMMARY
--
-- EXPORT STANDARD SUMMARY VARIABLE VECTORS TO FILE
--
ALL
--
-- FIELD SOLVENT INJECTION RATE
FNIR
--
-- FIELD SOLVENT PRODUCTION RATE
FNPR
--
-- FIELD SOLVENT INJECTION TOTAL
FNIT
--
-- FIELD SOLVENT PRODUCTION TOTAL
FNPT
The final part of the example covers the SCHEDULE section. The WSOLVENT keyword is used to specify the injected solvent fraction (in this case pure CO2).
-- ==============================================================================
--
-- SCHEDULE SECTION
--
-- ==============================================================================
SCHEDULE
--
-- RESTART CONTROL BASIC = 1 (LAST REPORT TIME ONLY)
--
RPTRST
'BASIC=1' 'ALLPROPS' /
--
-- DEFINE GAS INJECTION WELL SOLVENT FRACTION
--
-- WELL SOLVENT
-- NAME FRACTION
-- --------
WSOLVENT
GI01 1.0000 /
/

Manual source: parts/chapters/subsections/5.3/CO2SOL.fodt