A reservoir/wellbore model for multiphase injection and pressure transient analysis
A transient three phase (oil, water, gas) wellbore flow treatment based on the mixture flow model is developed and incorporated into a three phase reservoir flow model in a fully implicit simultaneous solution scheme of both reservoir and wellbore variables at each time step. The coupled reservoir/wellbore model permits either injection or production rates to be assigned at the surface and internally calculates sand-face rates between the wellbore and the reservoir. A variable bubble-point pressure capability is provided for both the wellbore and the reservoir flow. Model results for the injection case showed that current techniques used to handle phase injectivities at the reservoir/wellbore interface are not consistent with the equations governing flow in the wellbore. A new model to define the phase injectivities was proposed. Its results agreed reasonably well with laboratory results reported in the literature. This new model was also compared with a field stream injection case where it showed only a fair agreement. For multiphase production/buildup analysis, the reservoir/wellbore model was used to generate production/buildup data. Model calculations showed that it may take from less than an hour to up to a day to overcome wellbore storage effects. It is demonstrated that the model is also useful for obtaining the shut-in pressure behavior of the reservoir/wellbore system provided that there is no appreciable backflow of fluids from the wellbore into the reservoir, a phenomenon which causes an anomalous (humping) pressure buildup behavior reported in the literature for some gas-oil wells. The two-fluid well flow model was included in order to allow the simulation of these anomalous tests and to be able to check whether or not a well might be expected to exhibit such a behavior.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 6674766
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020300* -- Petroleum-- Drilling & Production
ASSOCIATED GAS
BOREHOLES
CAVITIES
ENERGY SOURCES
ENGINEERING
ENHANCED RECOVERY
FLOW MODELS
FLUID FLOW
FLUID INJECTION
FLUIDS
FOSSIL FUELS
FUELS
GASES
HYDROGEN COMPOUNDS
INJECTION WELLS
MATHEMATICAL MODELS
MULTIPHASE FLOW
OIL WELLS
OXYGEN COMPOUNDS
PETROLEUM
PRESSURIZING
PRODUCTION
RECOVERY
RESERVOIR ENGINEERING
RESERVOIR PRESSURE
TESTING
WATER
WELLS