Addressing the desertic carbonate CCUS monitoring challenge: lessons learnt from a case study from Sultanate of Oman

Paper presented at the SEG Workshop – Recent Advances in Geophysical Reservoir Characterization and Monitoring of CO₂ Sequestration in Carbonate Reservoirs held in Abu Dhabi, UAE, 21-23 May 2024 and presented by Mohamed Messamah.

Written by: Mohamed Messamah¹, Saif Azri², Habib Al Khati¹– 1 SpotLight, 2 PDO

Introduction:

Seismic monitoring of geological CO2 storage in desert environments dominated by carbonate reservoirs faces two critical challenges: seismic repeatability and 4D subtle signal. Repeatability is challenged by the complex and time-varying nature of the near surface in these environments, which generates strong surface waves and low-repeatable seismic signals over time (Smith et al., 2019). This noise, coupled with the weak 4D signal expected from injection into a stiff carbonate reservoir, makes mapping the time lapse signal very challenging (Smith et al, 2018).
To mitigate the near-surface effects and generate a clear seismic image, an increasing number of seismic sensors are required. To increase further the seismic repeatability, permanent buried receivers and extremely precise source positioning (Smith et al, 2018) coupled with a dedicated complex processing sequence appear to be mandatory to provide 4D images. However, deploying such a setup is costly, logistically challenging and environmentally unfriendly. If the economics of CCUS may justify such investment, it is not applicable for CCS. This is where innovative technology comes into play.
A first deployment of focused seismic monitoring, applied on a heavy oil field in central Oman, utilizes a light and cost-effective focused monitoring solution. The implementation of this technology has allowed for the identification of necessary adaptations and operational limits specific to carbonate reservoirs. Understanding these nuances is crucial for tailoring effective monitoring strategies in such challenging geological contexts. By reducing costs and adapting to surface conditions, this technology could enable CCS monitoring in desert environments.

Download: Abstract_SEG