Well performance under solutions gas drive
A fully implicit black-oil simulator was written to predict the drawdown and buildup responses for a single well under Solution Gas Drive. The model is capable of handling the following reservoir behaviors: Unfractured reservoir, Double-Porosity system, and Double Permeability-Double Porosity model of Bourdet. The accuracy of the model results is tested for both single-phase liquid flow and two-phase flow. The results presented here provide a basis for the empirical equations presented in the literature. New definitions of pseudopressure and dimensionless time are presented. By using these two definitions, the multiphase flow solutions correlate with the constant rate liquid flow solution for both transient and boundary-dominated flow. For pressure buildup tests, an analogue for the liquid solution is constructed from the drawdown pseudopressure, similar to the reservoir integral of J. Jones. The utility of using the producing gas-oil ration at shut in to compute pseudopressures and pseudotimes is documented. The influence of pressure level and skin factor on the Inflow Performance Relationship (IPR) of wells producing solution gas drive systems is examined. A new definition of flow efficiency that is based on the structure of the deliverability equations is proposed. This definition avoids problems that result when the presently available methods are applied to heavily stimulated wells. The need for using pseudopressures to analyze well test data for fractured reservoirs is shown. Expressions to compute sandface saturations for fractured systems are presented.
- Research Organization:
- Tulsa Univ., OK (USA)
- OSTI ID:
- 6987622
- Country of Publication:
- United States
- Language:
- English
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