Comprehensive Piloting Strategy to De-Risk First CO2 EOR Development in Sultanate of Oman
Authors: Nasralla Ramez , Gavnholt Jeppe , Al Baloshi Sameer , Amrani Reda , Aljiroudi Fadi , Borner Nicholas , Al Bulushi Nabil 
Published: February 2024

Petroleum Development Oman (PDO) possesses a substantial volume of hydrocarbons that are trapped in tight (&lt;5mD), thin reservoirs within their portfolio. In order to unlock these valuable resources and mitigate greenhouse gas emissions, PDO has devised a comprehensive strategy to employ Carbon Dioxide Enhanced Oil Recovery (CO2 EOR) techniques in these reservoirs. This paper outlines PDO's strategy to de-risk the CO2 EOR development by implementing a dedicated field trial of CO2 EOR.

The primary objective of the trial project is to address the key technical uncertainty surrounding CO2 injectivity in the tight-thin reservoirs. Conventional waterflood methods have proven ineffective due to poor injectivity, necessitating the exploration of alternative solutions. Additionally, since the project involves a green field development, the trial also aims to address uncertainties related to macroscopic sweep efficiency and potential recovery factor, which are crucial in evaluating the project's economic feasibility.

This paper discusses the concept, design, and execution strategy of the pilot project, which seeks to evaluate the technical and economic viability of CO2 EOR. The pilot project consists of two phases: a short-term trial to mitigate injectivity risks, followed by an extended trial to assess the sweep efficiency of CO2, contingent upon the success of the initial phase. Thus, these 2 phases can evaluate the technical and economic feasibility of CO2 EOR development. To ensure effective implementation of the plan, an innovative surface injection solution was devised, taking into account the complex challenges associated with the CO2 supply chain, including Health, Safety, and Environment (HSE) considerations, operational requirements, logistics, and procurement challenges. The integration of these crucial factors played a pivotal role in designing a well-suited CO2 EOR de-risking strategy for PDO.

In conclusion, PDO's pilot project represents a significant milestone in the development of tight and thin reservoirs using CO2 EOR. The findings and insights presented in this paper offer valuable knowledge and practical guidance for the industry. The systematic approach adopted to expedite PDO's inaugural CO2 pilot project highlights the potential of CO2 EOR as an effective method for maximizing hydrocarbon recovery while simultaneously contributing to greenhouse gas reduction. Moreover, the success of this pilot project will pave the way for unlocking similar oil reservoirs facing similar challenges, thereby expanding the application of CO2 EOR techniques, and further enhancing environmental benefits. Notably, the CO2 used in the development project is planned to be captured from a nearby gas processing plant, resulting in reduced CO2 emissions by safely storing it in the target reservoirs. This emphasizes the broader significance of PDO's commitment to advancing sustainable practices within the oil and gas sector.