A few assumptions suggested by the mechanism of anthropogenic land settlement due to fluid withdrawal lead to the development of a simplied subsidence model relying on one anisotropic diusion equation for the vertical displacement only. The model can be used in a generally heterogeneous porous medium, possibly with a non linear or plastic mechanical behavior, and subject to an arbitrary pore pressure variation. The present communication investigates the conditions under which such a model provides an outcome of comparable accuracy with respect to the solution of the classical equilibrium equations. The results show that the diusion model of subsidence gives a good prediction above the producing eld especially in case of a thin depleted reservoir embedded within weakly heterogeneous porous media with a Poisson ratio between 0.20 and 0.30, i.e. the vast majority of real applications. The above model allows also for a novel interpretation of the volumetric locking phenomenon occurring for a Poisson ratio close to its limiting value of 0.50 and helps gain a new insight in terms of equivalent mechanical conductivities into the propagation of the deep compaction to the land surface.

A diffusion model for land subsidence

FERRONATO, MASSIMILIANO;GAMBOLATI, GIUSEPPE;PUTTI, MARIO;TEATINI, PIETRO
2006

Abstract

A few assumptions suggested by the mechanism of anthropogenic land settlement due to fluid withdrawal lead to the development of a simplied subsidence model relying on one anisotropic diusion equation for the vertical displacement only. The model can be used in a generally heterogeneous porous medium, possibly with a non linear or plastic mechanical behavior, and subject to an arbitrary pore pressure variation. The present communication investigates the conditions under which such a model provides an outcome of comparable accuracy with respect to the solution of the classical equilibrium equations. The results show that the diusion model of subsidence gives a good prediction above the producing eld especially in case of a thin depleted reservoir embedded within weakly heterogeneous porous media with a Poisson ratio between 0.20 and 0.30, i.e. the vast majority of real applications. The above model allows also for a novel interpretation of the volumetric locking phenomenon occurring for a Poisson ratio close to its limiting value of 0.50 and helps gain a new insight in terms of equivalent mechanical conductivities into the propagation of the deep compaction to the land surface.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2444921
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact