Date of Award

5-1-1993

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Abstract

Multiphase flow is a common occurrence in the chemical and petroleum industries. The objective of this study was to apply the principles of multiphase flow to the production of petroleum fluids. A unified model was developed to predict the pressure profiles in wellbores using models available in the literature, which was then used to develop a simulator. A rigorous approach was also taken to model heat transfer and predict the temperature profiles in wellbores unde, various circumstances.

Our model is capable of predicting the pressure profiles for various channel orientation and geometries. It can handle flow in vertical, and inclined system. Countercurrent flow and flow in downward direction can also be simulated. With appropriate value for the parameters, the model applies to liquid-liquid systems in addition to the gas-liquid systems.

The temperature profile in a wellbore is important to the petroleum industry. Fluid temperature determines various properties such as viscosity, density, the extent of dissolved gases etc. The pressure profile depends on these physical properties. In addition, the temperature profile is important in many production operations in arctic regions. A prior knowledge of the temperature and pressure profile enables the operators to take preventive measures against the clogging of pipelines due to hydrate or wax formation. Accurate temperature estimation is also important during such operations as drilling, cementing etc.

Fluid temperature depends orji the extent of heat loss from the wellbore, which in turn, depends on the formation temperature. The present approach of temperature estimation assumes a constant heat flux between the wellbore and formation throughout the entire operation time. However, quite often the heat transfer rate between the formation and wellbore changes with time. We used the superposition principle to account for the gradual change of heat flux with time. Analytical solutions with the assumption of invariant and linear variation of heat flux with depth, and numerical solution of the governing differential equation were obtained.

We developed expressions for fluid temperature during production, injection and mud circulation. The results showed variation in the temperature profiles when superposition is used during oil production and in mud circulation compared to solution without superposition. The solutions of linear variation of heat flux with depth assumption were close to the numercial solutions.

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