Steamflooding Heavy Oil in a Naturally Fractured Carbonate Reservoir in Sultanate of Oman: A Case Study

Abstract

Since the discovery of the Khuff and Kahmah reservoirs at Mukhaizna field in 2010, Oxy Oman has faced a number of challenges in producing heavy oil (8000-20,000 cP) from these carbonate reservoirs. These large, low-productivity reservoirs have few analogues in the world, so Oxy has had to find our own way, pioneering new approaches to bring these reserves to market. In addition to the complicated geology of these naturally fractured, vuggy, and dolomitized carbonate reservoirs, identifying the right steam injection method and selecting the best artificial lift system were critical to the success of the project. This paper covers the staged field development methodology, which we found to be beneficial for reducing both geological and reservoir engineering uncertainties. We will share our analysis and evaluation of various development concepts, including steamflooding, sequential steam injection, and scheduling cyclic steam stimulation across the field to optimize overall field production rates. Our focus on data gathering and analysis has enabled us to optimize both our completion design and artificial lift selection, which has reduced downtime and lowered operating costs by nearly 50%. Persistent efforts by our engineers during the past two years have resulted in peak oil production this year – without any significant drilling activity.