Reservoir Redevelopment by CO2 Injection Using Compositional Model Simulation in Carbonate Oilfield

Abstract

1.1 Objectives/Scope
The SK field is a carbonate oil reservoir with current oil production decreased from +/- 28,000 BOEPD to around 10,000 BOPD due to highly decline rate. The objective of this study is to identify and propose CO2 Injection in order to sustain and increase the matured oilfield production & oil recovery by using the economic feasible CO2 EOR Technology. From this model and simulation study we found that this CO2 EOR Injection can be increase the recovery factor of this field by +7-9% of inplace.
1.2 Methods, Procedures, Process
The challenges of this study is to get the representative model with limited reservoir data by using some correlations. The reservoir is also quite complicated since the production data indicated that there are some fractures and permeability streak. Moreover, the well was completed with the poor quality of cementing bond and it was a challenge in the history matching process as well. EOS modelling is an essential part to build a compositional model. Being able to improve EOS model accuracy would make reservoir model more representatives. The number of component in EOS model also gives significant effect to running time of simulation and we have examined some EOS model to get the fastest running process. In development scenario, CO2 would be injected through top structure considering it's a thick reservoir and the injection pressure was set to near minimum miscible pressure to get near miscible condition.
1.3 Results, Observations, Conclusions
The result of this study by using CO, EOR compositional simulation showing the increasing of Oil Recovery by 4.03 % over the baseline (means another 11.96 MMBBL additional oil will be recovered by applying this technology to this oilfield) which is required 4 additional infill production well with 2 injection well).This paper will discuss the process of the simulation model from static modelling up to dynamic modelling through data gathering, EOS modelling, History matching up to the oil and gas forecasting by using Compositional Model. Using compositional model means the numerical computation would be more complicated than the conventional black oil simulation model and needed more running time, which will be more than triple or fourth time slower that the conventional one. Therefore, in order to boosting the running time of the simulation of this model, we are using 8 Core of the hardware of the computer to run our model. There are many interesting we found during our study by using this kind of model (Compositional Model) and by applying CO2 EOR injection with this model.