Numerical modeling of land subsidence above faulted reservoirs by interface elements,

The stress variation induced by the development of underground reservoirs may activate pre-existing faults. This may cause the opening or slip of the ftacture surfaceswith a possible impact on the expected land subsidencedue to the generation of mechanically weak points in the porous medium close to the producing field. Since traditional finite element models are not able to simulate such deformations, special interface elements should be used. In the present communication, a class of elasto-plastic interface elements, speciflcally designed to address the mechanical behavior of faults over a regional scale, is developed and integrated into a traditional geomechanical poroelastic model. This model is used in a realistic faulted reservoir to study the influence of fault deformations on land subsidence. It is shown that the proposed interface elements can be simply incorporated into a traditional finite element model improving the quality of the prediction made over faulted producing fields.