Monitoring, Measurement and Verification MMV: A Critical Component in Making the CO2 Sequestration Success

Abstract

The increasing atmospheric concentration of carbon dioxide (CO₂), a greenhouse gas (GHG) is creating environmental imbalance and affecting the climate adversely due to growing industrialization. Global leaders are emphasizing on controlling the production of GHG. However, growing demands of natural gas, industry is embarking on the development of high CO₂ contaminant gas fields to meet supply gap. Development and management of contaminated hydrocarbon gas fields add additional dimension of sequestration of CO₂ after production and separation in project management. CO₂ sequestration is a process for eternity with a possibility of zero-degree failure. Monitoring, measuring and verification (MMV) of injected CO₂ volume in sequestration is critical component along with geological site selection, transportation, storage process. The present study discusses all the impacting parameters which makes whole process environment friendly, economically prudent and adhering to national and international regulations. The migration of injected CO₂ plume in the reservoir is uncertain and its monitoring is equally challenging. The role of MMV planning is critical in development of high CO₂ contaminant fields of offshore Sarawak. It substantiates that injected CO₂ in the reservoir is intact and safely stored for hundreds of years after injection and possesses minimum to no risk to HS&E. The deployment of Multi-Fiber Optic Sensor System (M-FOSS) promises a cost-effective solution for monitoring the lateral & vertical migration of CO₂ plume by acquiring 4D DAS-VSP (Distributed Acoustic Sensor – Vertical Seismic Profile) survey and for the well integrity by analyzing DAS/DTS (Distributed Temperature Sensor)/DPS (Distributed Pressure Sensor)/DSS (Distributed Strain Sensor) data. Simulation results and injectivity test at laboratory for in-situ CO₂ injection has demonstrated the possibility of over 100MMscfd/well injection in aquifer to meet the total CO₂ injection of 1.2Bscfd for full field development while maintaining the reservoir integrity. Uncertainty & risk analysis shows possible presence of seismically undistinguished fractures and minor faults, an early breakthrough of injected CO₂ cannot be ruled out. The depleted reservoir storage study divulges the containment capacity of identified carbonate reservoirs as well as conformance of potential storage sites. The fault-seal analysis and reservoir integrity studies determine the robustness of the long-term security of the CO₂ storage. Injectivity study demonstrates the optimum and maximum possible rates of CO₂ injection into these depleted gas reservoirs. VSP simulation results show that a subsurface coverage of 3-4 km² per well is achievable, which along with simulated CO₂ plume extent help to determine the number of wells required to get maximum monitoring coverage for the MMV planning. The deployment of M-FOSS technology is novel and proactive approach to monitor the CO₂ plume migration and well integrity. First ever development of MMV Planning for CO₂ Sequestration in offshore Sarawak, Malaysia using novel and cutting-edge M-FOSS technology for proactive monitoring of CO₂ plume migration and well integrity.