Modeling of asphaltene and wax precipitation

Technical Report · Tue Jan 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/6347484· OSTI ID:6347484

Chung, F; Sarathi, P; Jones, R

This research project was designed to focus on the development of a predictive technique for organic deposition during gas injection for petroleum EOR. A thermodynamic model has been developed to describe the effects of temperature, pressure, and composition on asphaltene precipitation. The proposed model combines regular solution theory with Flory-Huggins polymer solutions theory to predict maximum volume fractions of asphaltene dissolved in oil. The model requires evaluation of vapor-liquid equilibria, first using an equation of state followed by calculations of asphaltene solubility in the liquid-phase. A state-of-the-art technique for C{sub 7+} fraction characterization was employed in developing this model. The preliminary model developed in this work was able to predict qualitatively the trends of the effects of temperature, pressure, and composition. Since the mechanism of paraffinic wax deposition is different from that of asphaltene deposition, another thermodynamic model based on the solid-liquid solution theory was developed to predict the wax formation. This model is simple and can predict the wax appearance temperature with reasonable accuracy. Accompanying the modeling work, experimental studies were conducted to investigate the solubility of asphaltene in oil land solvents and to examine the effects of oil composition, CO{sub 2}, and solvent on asphaltene precipitation and its properties. This research focused on the solubility reversibility of asphaltene in oil and the precipitation caused by CO{sub 2} injection at simulated reservoir temperature and pressure conditions. These experiments have provided many observations about the properties of asphaltenes for further improvement of the model, but more detailed information about the properties of asphaltenes in solution is needed for the development of more reliable asphaltene characterization techniques. 50 refs., 8 figs., 7 tabs.

• Research Organization: National Inst. for Petroleum and Energy Research, Bartlesville, OK (USA)
• Sponsoring Organization: DOE/FE
• DOE Contract Number: FC22-83FE60149
• OSTI ID: 6347484
• Report Number(s): NIPER-498; ON: DE91002217
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ASPHALTENES
ASPHALTS
BENCH-SCALE EXPERIMENTS
BITUMENS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON DIOXIDE INJECTION
CARBON OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
DATA
DEPOSITION
DEPOSITS
ENERGY SOURCES
ENHANCED RECOVERY
EQUATIONS
EQUATIONS OF STATE
EQUILIBRIUM
FLUID INJECTION
FLUIDS
FORECASTING
FOSSIL FUELS
FUELS
GASES
INFORMATION
LIQUIDS
MATHEMATICAL MODELS
MISCIBLE-PHASE DISPLACEMENT
MOLECULAR WEIGHT
OIL WELLS
ORGANIC COMPOUNDS
ORGANIC SOLVENTS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PARTICLE MODELS
PETROLEUM
PRESSURE DEPENDENCE
RECOVERY
RESEARCH PROGRAMS
RESERVOIR PRESSURE
RESERVOIR TEMPERATURE
SOLUBILITY
SOLVENTS
STATISTICAL MODELS
TAR
TEMPERATURE DEPENDENCE
TEST FACILITIES
THERMODYNAMIC MODEL
VAPORS
WAXES
WELL CASINGS
WELLS