SPWLA Distinguished Lecturer: Salinity Effect on CO2 Solubility in Live Formation Water Under Reservoir Conditions

Join the McDougall School of Petroleum Engineering to hear from senior reservoir engineer Jie Wang talk about salinity effect on CO2 solubility in live formation water under reservoir conditions.

CO2 can dissolve in fresh/saline water under typical reservoir pressure and temperatures with solubility dependent on pressure, temperature, and salinity. The typical assumption in open literature regarding CO2 solubility studies—that saline water or fresh water is considered a liquid without any pre-dissolved gases under pressures and temperatures—is not true because any formation water contains appreciable dissolved gases for all pressure and temperature conditions. An example of gas-water ratio (GWR) can be ~1 scf/stb for a saline aquifer and ~5 to 6 scf/stb for the formation of water in an oil reservoir. The first set of experiments evaluated the CO2 solubility in live formation water. The second set of experiments evaluated how variation in the live brine salinity affected CO2 solubility. These experiments involved a synthesis of the brine with three different salinities (low, medium, and high), recombination of live formation water, CO2 addition in a high-pressure and high-temperature pressure-volume-temperature (PVT) visual cell, and determination of bubble-point pressure within the PVT cell. The results showed that CO2 solubility in live formation water is significantly less than that in “dead” water under reservoir conditions. The CO2 solubility vs. pressure curve has a much steeper slope, which indicates that CO2 can no longer be dissolved in the live brine once it reaches a certain solubility. In addition, the brine salinity affects CO2 solubility in live formation water by further reducing CO2 solubility with increasing live brine salinity. Understanding CO2 dissolution in live saline water is essential for future carbon capture and sequestration (CCS) evaluation and execution.

SPEAKER INFO:

Jie Wang joined Intertek Westport Technology Center in March 2021 as a senior reservoir engineer. She is currently a PhD candidate in petroleum engineering at the University of Houston. Jie has worked in the oil & gas industry for more than 25 years focusing on reservoir engineering, including reservoir fluid characterization (PVT test and EOS modeling), special core analysis (SCAL test and numerical analysis), reservoir simulation, as well as enhanced oil recovery (EOR) for both laboratory EOR test evaluation and subsequent reservoir simulation studies.