Monitoring an appropriate set of performance metrics is an essential part of a reservoir management strategy that seeks to maximize the efficiency of CO2-EOR floods, and benchmark the performance of the reservoir to other fields in the region. While a number of studies have outlined various options for evaluating the performance of the reservoir, many are not applicable to depleted oilfields that are commonly encumbered with limited data availability. As interest in CO2-EOR grows beyond giving new life to old fields, into a means of reducing anthropogenic CO2 emissions, metrics that enable the analyst to assess the storage capacity of the reservoir in addition to oil recovery efficiency have also become increasingly desirable. This paper will present a streamlined set of metrics that meet these objectives, along with their implementation in a dashboard-style presentation. These metrics provide complementary and non-redundant information, and crucially, are still applicable where a paucity of pressure data exists. The analyst is equipped with four groups of critical information. These are (A) flow rate and cumulative production data; (B) EOR performance trends (incremental oil recovery efficiency, CO2 storage efficiency, and net CO2 utilization factor); (C) operational performance trends (voidage replacement ratio and producing CO2-oil ratio); and (D) storage performance trends (incremental oil recovery factor vs. CO2 storage and CO2 storage capacity vs. voidage). To facilitate comparison, all metrics are normalized to percentage of original hydrocarbon pore volume (HCPV) injected.
The utility of the selected set of metrics is demonstrated with data obtained from CO2-EOR activities in depleted oilfields of the Midwest Regional Carbon Sequestration Partnership (MRCSP) region. First, a nine-panel dashboard is populated using the metrics discussed for the D-33 reservoir, and will be shown to be useful in: quantifying CO2 storage capacity, highlighting reservoir performance parameters (CO2 breakthrough, oil recovery, voidage-related pressure changes during EOR etc.) and identifying CO2-flood maturity. Second, a four-panel dashboard is displayed as a comparative tool across all reservoirs in the region in order to highlight best and worst performing reservoirs and establish representative ranges for reservoir performance. Both dashboards will be useful when comparing performance against averages published in literature.
This work's novelty is attributed to presenting an ideal set of performance metrics by streamlining the numerous options available. A unique dashboard-style presentation is suggested as a means of rapidly assessing oil recovery and CO2-storage performance, and collectively yielding useful insights.
Natural fractures affect both the oil recovery from the enhanced oil recovery (EOR) process and the associated CO 2 storage during and after EOR. The main objective of this study is to evaluate two performance parameters: (1) oil recovery during CO 2 and water alternating gas (WAG) injection, and (2) CO 2 storage, during and after EOR, in a fractured oil reservoir of the Appalachian basin. While previous studies have shown the potential of CO 2-EOR to enhance oil recovery in the Appalachian basin, this work investigates WAG performance in comparison to continuous CO 2-EOR. A compositional numerical modeling approach was used to quantify the incremental oil recovery stemming from incorporating natural fractures. History matching of primary production and CO 2 huff-and-puff pilot test for a well producing from a depleted oil field in Ohio was used to assign the fracture network parameters in the dual continuum model. The scenarios modeled include continuous CO 2 and WAG injection under two injection pore volumes. Each scenario is followed by a CO 2 storage phase. These simulations help evaluate the performance of different scenarios in terms of oil recovery and CO 2 storage. Simulation results show how oil recovery and CO 2 storage vary significantly as a function of operational parameters. The results also show the amount of CO 2 stored during WAG injection is significantly lower than that stored during the storage phase at the end of oil recovery. In addition, the operational parameters during WAG affect the amount of CO 2 stored at the end of following storage phase.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.