Sensitivity analysis and model type evaluation for subsidence above offshore gas reservoirs
conference paper
This paper describes the results of a sensitivity study conducted to understand how the prediction of subsidence due to gas extraction from offshore gas fields depends on a few key parameters, such as connection to the adjacent aquifers and material mechanical properties. The analysis has been performed using an axi-symmetric FE-model. A specific gas production field, the Naomi-Pandora gas field in the Northern Adriatic basin, has been assessed in detail. For each of the layers considered in the stratification a low value, an intermediate and a high value for the stiffness was applied, as determined from oedometer tests, radioactive markers and vertical seismic profiling respectively. The reservoir constitutive behavior has been modeled using different approaches, namely: a linear-elastic, a power law and a Modified CamClay model. The study has been performed for different pressure scenarios representing different levels of interaction with adjacent aquifers. The results show the sensitivity of the subsidence bowl as a result of the imposed conditions. These results are compared with the predictions obtained using 3D non-linear elastic and hypoplastic subsidence models of the same gas fields, demonstrating a good agreement.
TNO Identifier
504653
Source title
Proceedings of the 7th International Symposium on Land Subsidence, SISOLS 2005, Shanghai, China, 23-28 October 2005
Editor(s)
Barends, F.B.J.
Carbognin, L.
Gambolati, G.
Steedman, R.S.
Carbognin, L.
Gambolati, G.
Steedman, R.S.
Collation
14 p.
Pages
65-78
Files
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