Cost-efficient CO2 monitoring technology (Task 12)

One of the keys for safe CO2 storage is that industry operators comply with monitoring regulations. Monitoring the storage site is potentially very expensive. The main ambition is to develop and demonstrate monitoring technology which will enable safe operation in compliance with laws and regulations in the most cost-efficient manner.

One of the keys for safe CO2 storage is that industry operators comply with monitoring regulations. Monitoring the storage site is potentially very expensive. The main ambition of this Task is to develop and demonstrate monitoring technology which will enable safe operation in compliance with laws and regulations in the most cost-efficient manner. This will benefit our industry partners, like Shell, Statoil, Total and others.

To ensure optimal industry relevance and the highest possible relevance for the Northern Lights project (Statoil, Shell and Total's carbon storage project) on the Norwegian Continental Shelf at Smeaheia, the industry will be closely involved thorough the lifetime of the Task. Involvement of vendors with expertise from oil and gas monitoring will also be important, and we will seek to have a dialogue with regulators.

Most of the monitoring activities in this Task are related to both Deployment Cases, since similar geophysical monitoring technologies are expected to be used in both cases.

Main results 2019

Reliable monitoring of a CO2 storage site is essential for safe and efficient operation, as well as for public acceptance. By carefully monitoring the site before, during, and after CO2 injection, the risk for very costly intervention, remediation, or site closure is significantly reduced. Such surveillance can potentially be very expensive. The main ambition of Task 12 is to develop and demonstrate monitoring technology which will enable safe operation in compliance with laws and regulations in the most cost-efficient manner.

During the year, we applied a newly developed approach for reservoir parameter estimation with uncertainty quantification (Bayesian Rock Physics Inversion) to Sleipner 2008 seismic data. We demonstrated how important reservoir parameters, such as CO2 saturation and reservoir pressure, can be estimated with a simultaneous assessment of uncertainty, providing essential operational information to the storage site owner. Initial studies also showed how the estimated reservoir parameters can be used to constrain and calibrate reservoir simulations of the Sleipner injection. This calibration enables improved prediction of the future behaviour of the storage site.

The development and testing of a compressive sensing technique for enhanced geophysical data acquisition and interpretation continued in 2019. This technique, which can help to reduce the need for dense (and expensive) seismic surveys, was succesfully verified for sparse subsets of Sleipner data.

Reliable and cost-efficient monitoring will be essential for the Northern Lights project. Task 12 developments like the ones described above will support the design of an optimal monitoring scheme. Another such example is how the research and development of Controlled Source Electro-Magnetics (CSEM), as a complement to seismic, could provide a more cost-efficient and accurate approach for quantitative CO2 monitoring. Based on synthetic Smeaheia data, a quantitative CSEM inversion study was successfully concluded in 2019 (see the figure). Results show that CSEM can be used to give accurate volume estimates.

For any future storage project, there is also a great value in the research efforts on value-of-information, which offer new ways for an operator to analyse and select optimal geophysical monitoring strategies. During 2019, a conceptual Smeaheia case was used to demonstrate how a novel method for value-of- information analysis, based on machine learning, can be used to determine the optimal way of detecting potential leakage from CO2 storage.

In 2019, we also initialised two spin-off projects (EM4CO2 and Tophole) for more detailed studies of two important topics. EM4CO2 investigates the use of electro-magnetic methods as a complement to seismic for more quantitative reservoir monitoring information. Tophole studies how the integrity of plugged and abandoned wells can be cost-effectively monitored to enable CO2 storage in regions with existing wells.

CO2 volume estimations from CSEM inversion results. Left: True model, Middle: Result with unconstrained inversion, Right: Result with constrained inversion.

Results 2018

Main Results

  • Smeaheia baseline geophysical models and rock physics models built using Gassnova seismic data (Fig. 1)
  • Sensitivity test of CO2 injection on seismic observables at Smeaheia
  • Initial sensitivity studies for use of CSEM at Smeaheia (Fig. 1)
  • Demonstration of joint rock physics inversion approach at Sleipner using CSEM and seismic 2008 datasets
  • Validation of compressive sensing strategy for improved cost-efficient imaging
  • New survey optimization strategy tested
  • Work on combined modelling-monitoring and "history matching" initiated
  • Evaluation of cost-saving potential of NCCS CO2 monitoring developments

Impact and innovations

  • First application of FWI to get most out of Gassnova's 3D seismic data at Smeaheia could become useful for Northern Lights project for reservoir seal characterization and monitoring planning
  • The compressive sensing approach can help to reduce the need for dense (and expensive) seismic surveys
  • Survey optimization technique and combined modelling-monitoring workflow will help to find cost-efficient ways of confirming site conformance during injection
Selected results from Task 12 in 2018. [top left] P-wave interval velocity model in depth for a subset of the Inline 1024 from Gassnova's seismic cube GN1101. [top right] P-wave velocity model derived from FWI for the subset of Inline 1024 (from Dupuy et al. 2018, to be published). [middle left] 2.5D true resistivity models for simulated injection at Smeaheia until 2045. [middle right] CSEM inversion results. [bottom] A survey optimization strategy was developed and tested for synthetic Sleipner CSEM case. Circles representing optimal lateral source position and sensitivity (area). Each source is used together with all five receivers (represented by red triangles).

Results 2017

The task focused on setting up synthetic Smeaheia geophysical models, on developing new approaches for efficient use of available data for quantitative CO2 monitoring, and on using a statistical value-of-information concept for cost-minimization of CO2 monitoring.

For Smeaheia, Statoil's CO2 injection simulations were used to build synthetic models of the subsurface acoustic velocity, resistivity, and density at different times during and after the injection. These models together with Smeaheia data provided by Gassnova will serve as very important input for targeted Smeaheia monitoring studies in the years to come in NCCS.

Work on quantitative CO2 monitoring at Sleipner led to promising results that was presented at several workshops and conferences and published in several journals. In total, six publications were produced.

Industry partners Statoil, Shell and Total, as well as vendor Quad Geometrics have contributed to the task and participated in a workshop in September. Late in 2017, EMGS confirmed that they want to join the task as a vendor.

Journal Publications

2018:

2017: 

 

Conference Publications

2018:

  • Bandlimited optimal AVO inversion for improved quantitative imaging of the CO2 Plume - A. Ghaderi, B. Dupuy, E. Querendez, P. Eliasson. GHGT-14, Melbourne
  • Estimating the impact of large-scale and sub-scale structural trapping on long-term CO2 plume migration in the Gassum Formation using seismic line data - O. Andersen, H.M. Nilsen, U. Gregersen, A. Sundal. GHGT-14, Melbourne
  • Optimized geophysical survey design for CO2 monitoring - A synthetic study - A. Romdhane, P. Eliasson. GHGT-14, Melbourne
  • Smeaheia baseline geophysical models - B.Dupuy, E. Querendez, A. Ghaderi, A. Romdhane, P. Eliasson. GHGT-14, Melbourne
  • Uncertainty quantification for CO2 monitoring methods applied to Sleipner and Smeaheia data - P. Eliasson, A. Romdhane. GHGT-14, Melbourne

 

Task leader