Potential evaluation of CO2 EOR and storage in oilfields of the Pearl River Mouth Basin, northern South China Sea

The Pearl River Mouth Basin (PRMB) is the largest petroliferous sedimentary basin in the northern South China Sea. It is near the coastal economic zone of Guangdong province where a large number of CO2 emission sources are located. Carbon dioxide enhanced oil recovery (EOR) represents an opportunity to promote offshore carbon capture, utilization and storage (CCUS) deployment because CO2 flooding offers a method to recover additional oil while simultaneously sequestering anthropogenic CO2. In this paper, a comprehensive multiparameter ‘quick look’ and potential evaluation method was proposed to screen and assess offshore CO2 EOR potential. A screening scheme for the CO2 EOR potential of reservoirs of the PRMB was also proposed using additional parameters, including reservoir properties and engineering design incorporating a dimensionless screen model and calculations. The results show that the suitability of reservoirs for CO2 EOR and storage varies and could be categorized into four priority grades. Approximately 30 of the oil reservoirs from 10 oilfields were preferentially identified by applying the screening method for reservoirs with predicted higher ultimate recovery potentials. It was predicted that 3227 × 104 t of additional oil could be produced from these reservoirs and that 3617 × 104 t of CO2 could be simultaneously stored. The sensitivity analysis shows that injection pressure (Pinj) would be more sensitive than production pressure (Pp) and well distance (L) on the CO2 EOR and storage efficiency, indicating that EOR operations with higher Pinj may improve oil production. The prospective reservoirs include those candidates with suitability grades of I and II from the Lufeng (LF) and Huizhou (HZ) oilfield clusters, where 1164 × 104 t of additional oil could be produced and 1464 × 104 t of CO2 stored with CO2 EOR. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

Sensitivity Analysis Of The Dimensionless Parameters In Scaling A Polymer Flooding Reservoir

A set of scaling criteria of a polymer flooding reservoir is derived from the governing equations, which involve gravity and capillary force, compressibility of water, oil, and rock, non-Newtonian behavior of the polymer solution, absorption, dispersion, and diffusion, etc. A numerical approach to quantify the dominance degree of each dimensionless parameter is proposed. With this approach, the sensitivity factor of each dimensionless parameter is evaluated. The results show that in polymer flooding, the order of the sensitivity factor ranges from 10(-5) to 10(0) and the dominant dimensionless parameters are generally the ratio of the oil permeability under the condition of the irreducible water saturation to water permeability under the condition of residual oil saturation, density, and viscosity ratios between water and oil, the reduced initial oleic phase saturation and the shear rate exponent of the polymer solution. It is also revealed that the dominant dimensionless parameters may be different from case to case. The effect of some physical variables, such as oil viscosity, injection rate, and permeability, on the dominance degree of the dimensionless parameters is analyzed and the dominant ones are determined for different cases