EOR of Sour Oil Field Through CO2 Miscible Gas Injection: De-Bottlenecking Challenges for Surface Facilities

The cluster of fields under the scope of the study are located in South of Oman. Most of the fields are located within a salt basin. The fields were discovered in different periods and all are under production. The study was focused on the largest two fields in the area that are currently under Miscible Gas Injection (MGI) as means of Enhanced Oil Recovery (EOR). Both of the fields have been under MGI for over 10 years, with sour gas produced from the two fields, among other fields, is re-injected into the reservoir. A small fraction of the produced sour gas is treated and exported as sales gas to a nearby pipelines. The sales gas is mostly used for power generation. The re-injected gas used for MGI consists of a significant gas bubbles that is currently used for EOR purposes. If the current EOR scheme continues, the gas bubble cannot be commercialized until most of the oil reserves are produced. The objective of the study was to assess the feasibility of Carbon Dioxide (CO2) utilization for EOR of the oil fields through additional oil miscibility by replacing sour natural gas injection with acid gas injection (i.e. CO2 injection). The study also intended to quantify the amount of natural gas that can be displaced with CO2 injection, and the overall economics of the project.