Multiphase flow application to ESP pump design program

The exploitation of a hydrocarbon reservoir may involve the flow of liquids and gases together. The simultaneous flow of these fluids is called multiphase flow. During the production process, the produced fluids are submitted to changes in pressure and temperature. As a result of these changes in pressure and temperature, the fluids physical properties change. The changes in volume of the liquid systems are due to gas liberation, reduction in pressure, and reduction in temperature. Viscosity, surface tension, and other physical properties are functions of pressure and temperature. Therefore, these properties are different for different conditions.

The design of well artificial lifr systems and well completion strings involves the calculation of pressure gradients. The determination of these pressures gradients requires the use of in-situ rates and the knowledge of the different fluid physical properties. Finding the value of the pressure gradients for multiphase flow is not easy. The reason for this is that the simultaneous flow of gases and liquids involves slippage between the phases. This slippage involves transfer of energy from gases to liquids and to the surroundings. An analytical solution does not exist. Therefore, the use of empirical correlations is necessary. Additionally, the PVT analysis from the fluids is not always available, and again, the use of empirical correlations for the determination of these properties is necessary.

ESPs are designed to lift water. Operators and pump companies do not account for the estimation of pressure losses for multiphase flow nor the in-situ volumetric flow rates for the selection design of these pumps. The purpose of this thesis is the application of correlations for estimation of pressure losses in multiphase flow and the use of in-situ volumetric flow rates for the calculations of selection design for ESPs. A computer program that contains these correlations was translated from FORTRAN to Basic.

Three topics in the literature review are covered. These topics comprise multiphase flow methods, PVT relationships and generalities about ESPs. Chapter 2 is a review of multiphase flow correlations. The methods by Hagedom and Brown, Duns and Ros, Beggs and Brill, and Orkiszewski are discussed. Chapter 3 covers the different fluid physical properties. PVT correlations are presented. A set of references about the different correlations is provided. Chapter 4 covers information of ESPs. This information is about the ESP system, typical installation, ESP system components, selection data and method, and troubleshooting. Chapter 5 presents information about the computer program that was translated. Information such as some small changes in the original program, a flow diagram for the determination of pressure traverse, why the change from FORTRAN to BASIC was made, problems in the translation, and results are covered. Chapter 6 finishes with some conclusions about the project in general and presents some recommendations for future work.