CO2 flooding is known to be one of the most applied miscible EOR process in E&P industry given its ability to mix with reservoir oil and form a miscible flood at relatively low reservoir pressures. CO2 EOR pilots' locations selection, configurations and design are key for success of an EOR piloting scheme. This goes without withstanding detailed compositional simulation to replicate components exchange under the MCM process as well as potential implications on existing well completions and surface facilities.
A structured workflow was established to rank and prioritize all reservoir units in terms of their suitability for miscible EOR. A thorough scrutiny of pilot locations, configuration as well as pilot design as a whole was undertaken. This was aimed to short-list preferred pilot locations and configurations that address most of remaining uncertainties. It was also intended to establish a list of expected deliverables from the pilots. Numerous pilot configurations were analyzed and ranked based on the size of EOR prize, uncertainties reduction as well as capturing synergies and common objectives across the reservoir units.
Detailed compositional simulation studies are being undertaken. This included one-dimensional models for the purpose of examining the displacement process; 2D mechanistic models to assess the impact of heterogeneity on the displacement process as well as fine grid pilot models for the purpose of optimizing the pilot design. A probabilistic production forecast of each pilot is also considered aiming to capture a range of possible outcomes and identify key uncertainties to be acted upon.
A tailored monitoring program is being designed to acquire key performance data including production and saturations monitoring, fluid sampling and pressures. This will feed inputs to sector model calibration as well as the evaluation of pilot performances.
Results from this study are expected to assist ADCO to plan and implement the EOR road map while accounting for all related issues such as flow assurance and asphaltene deposition, reservoir pressure maintenance, CO2 strip-out and re-injection as well as its impact on existing facilities.