| Fracture scenarios and their predictions for CO2 mobility |
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One of the highlights of our 2009 Technology Meeting is in Wednesday Session 3 - CCS and rad-waste focus with keynote speaker Sean Kelly (Lead Geologist, Maersk Oil).
Midland Valley have already opened their CO2 portfolio working on the In Salah CO2 storage project for the StatoilHydro, BP, Sonatrach joint venture. Over 3 million tonnes of CO2 have been injected at the site since 2004. The joint venture and partners are running a series of monitoring and evaluation projects designed to prove through short term monitoring the long term feasibility of an industrial scale CO2 storage site. These projects include InSAR analysis, 4D seismic, micro-seismics, tiltmeters, experimental rock deformation and more. Midland Valley are analysing the evolution of the reservoir structure by combing regional information from 2D seismic lines and well data with local 3D seismic. Understanding the evolution of the structure through time will allow Midland Valley to create scenarios for fracture generation in the reservoir and to use these scenarios to predict fluid flow. Once the final structural model has been created and validated through restoration the structural evolution is forward modelled. During the forward modelling strain is captured in the reservoir volume and used as one of several potential inputs for fracture density and orientation in the fracture modelling. Multiple fracturing scenarios are created by changing the assumptions of the controlling factors such as the dominance of the in situ stress field and the influence of early structures on fracturing. These fracture scenarios and their predictions for CO2 mobility will then be tested against well injection data and information collected from the other monitoring projects including InSAR and 4Dseismic.
The image shows part of a restored reservoir surface with strain intensity colour mapped (hot colours = high intensity). This strain information can be used as a proxy to determine fracture intensity in potential CO2 storage sites.  |