The behavior of producing gas-oil ratio (GOR) in unconventional reservoirs like liquid-rich shales (LRS) and conventional reservoirs differ. This is mainly due to major disparity in the permeability – ultra-low in unconventional reservoirs in comparison to that in conventional (higherpermeability) reservoirs. The ultra-low permeability and porosity of shales, among other factors contribute to the complex fluid flow mechanisms in these plays. Therefore, there is a need for a good comprehension of the physics of flow in liquid-rich shale reservoirs. This paper particularly investigates how various factors, ranging from critical gas saturation to compaction affect producing gas-oil ratio behavior in liquid-rich shale (LRS) reservoirs. Ten different moderately volatile and highly volatile (near-critical) oil fluid compositions were considered. Compositional reservoir simulations for a period of 30 years were run on a base case multi-fractured horizontal well (MFHW) model for each fluid type. Results showed that the different factors had varying impacts on the production performance and GOR behavior of LRS reservoirs – some more influential than others. Also, the fluid type, whether moderate or highly volatile oil, play a major role in determining how producing gas-oil ratios (GOR) behave in a LRS reservoir. A proper understanding of unconventional reservoir production mechanisms is necessary for reliable reserves estimation, production forecasting and improving oil recovery. This work contributes to this mission and provides a better understanding of the performance of liquid-rich shale plays.
The behavior of producing gas-oil ratio (GOR) in unconventional reservoirs like liquid-rich shales (LRS) and conventional reservoirs differ. This is mainly due to major disparity in the permeability – ultra-low in unconventional reservoirs in comparison to that in conventional (higherpermeability) reservoirs. The ultra-low permeability and porosity of shales, among other factors contribute to the complex fluid flow mechanisms in these plays. Therefore, there is a need for a good comprehension of the physics of flow in liquid-rich shale reservoirs. This paper particularly investigates how various factors, ranging from critical gas saturation to compaction affect producing gas-oil ratio behavior in liquid-rich shale (LRS) reservoirs. Ten different moderately volatile and highly volatile (near-critical) oil fluid compositions were considered. Compositional reservoir simulations for a period of 30 years were run on a base case multi-fractured horizontal well (MFHW) model for each fluid type. Results showed that the different factors had varying impacts on the production performance and GOR behavior of LRS reservoirs – some more influential than others. Also, the fluid type, whether moderate or highly volatile oil, play a major role in determining how producing gas-oil ratios (GOR) behave in a LRS reservoir. A proper understanding of unconventional reservoir production mechanisms is necessary for reliable reserves estimation, production forecasting and improving oil recovery. This work contributes to this mission and provides a better understanding of the performance of liquid-rich shale plays.