Self-Scaling in producer by PHREEQC

[trungka]

Dear Sirs,
I'm a newbie of Phreeqc. Can someone help me to write a code for my problem? I would like to calculate the scale tendency from reservoir to wellhead of a producer.
I have a production water composition, gas composition and oil composition. All data were analysed at 25oC. Firstly, I want to saturated the water, gas, and oil to reservoir condition and SI with Calcite = 0. Then I change the T,P condition to see the SI of Calcite from bottom hole to wellhead. The following is my procedure (key word only):
- SOLUTION 1 (Define production water, including pH and Alkalinity);
- GAS PHASE 1 (Define gas composition, CO2 and CH4 only);
- USE SOLUTION 1;
- USE GAS PHASE 1;
- EQUILIBRIUM PHASE
temperature 120 oC
Pressure 200 atm
Calcite 0
- SAVE SOLUTION 1
- USE SOLUTION 1
REACTION TEMPERATURE
115 oC (Change to bottomhole condition)
REACTION PRESSURE
150 atm (Change to bottomhole condition)

So, please help me to fix the above procdure. Thank you very much

[dlparkhurst]

Maybe something like

Code: [Select]

SOLUTION 20C, 1 atm
END
EQUILIBRIUM_PHASES
CO2(g)  log pressure
CH4(g)  log pressure
Calcite   0
REACTION_TEMPERATURE
REACTION_PRESSURE