Course objectives: By taking the exam, the student will be able to use the PVT report, will know the methods and procedures of collecting PVT data and laboratory PVT analysis. Based on the above, they will be able to create a PVT model using PVT simulation software and prepare PVT data for further analytical and simulation models.

Course content: 

• Measurement, processing and application of pVT data for the purpose of reservoir engineering:
  • Methods of sampling certain types of fluids;
  • PVT experiments (by type of fluid);
  • Theory of real gas equations used in reservoir engineering;
  • Parameters of the respective equations;
  • Correlations of acentric factors, definition and meaning of binary interaction parameters, volume shift; 
  • Initial assumptions of (Ki) phase equilibrium;
  • Muscat & Mcdowell (Rachford and Rice) calculation of fluid composition during separation (two-phase range or saturation pressure boundary conditions);
  • Creating a spreadsheet (MS Excel) or creating a computer code for the equation of Peng and Robinson (PR) and Soave-Redlich-Kwong (SRK); 
  • Mixing rules; Mixing rule algorithms for individual parameters of the state equation;
  • Comparison of analytically determined values with the results in PVT simulator;
  • Calculation of PVT properties by real gas equations (made PR and SRK) for mixtures, applying RR calculations, mixing rules and equations of state;
  • Pseudoization methods (splitting plus fractions), statistical distribution in the composition of plus fractions;
  • Algorithm for Whitson's splitting method;
  • Examples of different phase diagrams, depending on the type of fluid (display of phase diagrams based on typical compositions in PVT simulator);
  • Adjustment of volume factor correlation parameters according to laboratory analysis data (development of a new correlation).
• Calculation of the equation of state (using computer language Python):
  • Development of computer code for phase equilibria calculation;
  • Development of computer code for calculation of real gas volume by van der Waals method;
  • Development of computer code for calculation of real gas volume by SRK method; 
  • Development of computer code for calculation of real gas volume by PR method;
  • Creating computer code for mixing rules; 
  • Development of computer code for calculation of phase equilibrium (quantities and component compositions of liquid and gas phase), by real gas equation;
  • Solving convergence problems when calculating fugacity coefficients (for phase equilibrium); 
  • Development of computer code to assess the conditions of hydrate formation;
  • Other equations (PC SAFT, BWR);
  • Calculation of CO₂ emissions by hydrocarbon combustion, based on the previously calculated composition;
• PVT simulation:
  • Introduction to pVT simulation (Schlumberger pVTi, IPM PVTp);
  • The usual sequence of procedures for adjusting the equation of state;
  • Adjustment of the equation of state, ie parameters of plus fraction using pVT simulator;
  • Simulation of pVT experiments;
  • Comparison of the results obtained by spreadsheets in Excel and the results obtained by a pVT simulator (Schlumberger pVTi) for a one-component fluid;
  • Comparison of results obtained by spreadsheets in Excel and results obtained by pVT simulator (Schlumberger pVTi) for binary system;
  •  Comparison of Schlumberger pVTi simulator and Petroleum Experts pVTp simulator in the calculation of the phase diagram of different given binary compositions;
  • Input of laboratory analyses in pVT simulator (oil, condensate, gas);
  • Characterization of the oil system by pVT simulator - harmonization of the equation of state with real laboratory analyzes (saturation pressure, p-V isotherm, DL test);
  • Characterization of the gas system by pVT simulator - matching of the equation of state with real laboratory analyzes (dew point pressure, pV isotherm);
  • Characterization of the condensate system by a pVT simulator - harmonization of the equation of state with real laboratory analyzes (dew point pressure, pV isotherm, CVD test);
  • Simulation of PVT experiments based on adjusted equations of state;
  • An example of making "Black Oil" table for application in a reservoir simulator;
  • Exporting the equation of state for usage in a compositional reservoir simulator - an example of initialization of fluid properties for reservoir simulators;
  • Simulation of a slim-tube test for the purpose of determining multi-contact mixing pressure;
  • Predictive model of hydrate formation conditions and simulation determination of required inhibitor amount.

Learning outcomes at the level of the course:

• Calculate volumetric changes of real fluids by iterative procedures;
• Identify the advantages and disadvantages of individual methods of obtaining pVT data;
• Explain the physical relations of the parameters of cubic pVT equations of state for a real fluid;
• Show the procedure of mathematical splitting and grouping of hydrocarbon plus fractions;
• Devise a procedure for adjusting the parameters of the gas equation of state with a numerical pVT simulator (Schlumberger pVTi);
• Show the structure and method of preparing and writing pVT reports;
• Propose the method of obtaining, processing and application of pVT data on reservoir fluids for the needs of reservoir engineering;
• Prepare the input data for the pVT simulation and modify the equation of state.