Produced gas-oil ratio, abbreviated as GOR, is used in the petroleum industry to measure the volume of gas produced in relation to the volume of oil produced from a reservoir. The GOR is used for understanding the behavior of a reservoir and for making decisions regarding production strategies and reservoir management.
Key Points about gas-oil ratio
- GOR Types
- Solution GOR - The gas that is dissolved in the oil under reservoir conditions and comes out of solution as pressure decreases.
- Producing GOR - The actual ratio measured at the surface during production.
- Importance
- Reservoir Characterization - Helps in understanding the nature of the reservoir fluid. High GOR can indicate a gas cap above the oil column or the depletion of oil and breakthrough of gas.
- Production Strategy - Affects decisions regarding well completion, production facilities, and artificial lift requirements.
- Economic Analysis - Impacts the economic viability of a reservoir. Gas can be a valuable byproduct or a challenge if there is no market for it or if handling is expensive.
- Factors Influencing GOR
- Reservoir Pressure - As pressure decreases, more gas comes out of solution, increasing GOR.
- Production Rate - High production rates can lead to higher GOR due to greater pressure drops.
- Reservoir Characteristics - Heterogeneity, permeability, and fluid properties also impact GOR.
Applications of gas-oil ratio
- Well Testing - Helps in evaluating the performance of a well and predicting future production.
- Reservoir Simulation - Used in models to simulate reservoir behavior and predict future production scenarios.
- Enhanced Oil Recovery - Decisions on gas injection or other EOR techniques can be influenced by the GOR.