Isamgeo Finite Element Simulator
For most of the geomechanical services, Isamgeo team uses the Isamgeo FE Simulator, state-of-the-art, proprietary software developed by Isamgeo researchers. The simulator has been used in numerous finite element geomechanical studies for the petroleum industry. Main applications are full field compaction and subsidence studies as well as well bore stability analyses, with special focus on the stability of multilateral well (MLW) junctions. Its code has several important characteristics that make it suitable especially to fulfill the requirements of the oil&gas industry, in particular:
It is equipped with libraries of iterative solvers for symmetric and non-symmetric matrices, designed to solve efficiently the scattered large systems that typically arise from the integration with finite elements of partial differential equations (PDEs) on three-dimensional domains. Several preconditioning techniques are also implemented, specifically designed for nonlinear problems in geomechanics, ensuring considerable speed-up that allow fast analyses on particularly refined grids (orders of magnitude of 106 degrees of freedom). Multifrontal parallel direct solvers are also available for hill-conditioned systems, such as those arising in coupled analysis and modelling of shear failure (shear strain localization).
It assembles the nodal forces generated by the change of pressure in the reservoir and aquifers in manners that ensure that the pressure variation is contained within the cells that are actually depleted, not involving the nearby layers with spurious deformation effects;
It has the capability of managing over-consolidated states in formations and/or regions of the computational domain using appropriate constitutive laws.
It implements a large number of stress-strain models and failure criteria, suitable to model a variety of materials (including clastic formations, high porosity chalk, salt domes, etc.).
It implements the Cosserat numerical approach, a higher order method which can be used to simulate shear strain localization and the formation of breakouts. The Cosserat approach is important for modelling discontinuities (faults, fractures, caprock integrity), wellbore stability and the back analysis of some lab tests.
The code has the option to solve the single-phase fluid flow using a fully coupled approach, an important feature for wellbore stability studies and possibly also useful at the field scale.
The ISAMGEO code also implements rate-dependent models, which are able to reproduce the apparent visco-plastic behavior observed in some chalk and sand/sandstone formations.
The code covers standard stress strain relationships, such as the Modified Cam-Clay, standard Mohr-Coulomb and Drucker-Prager models, as well as specific constitutive relationships developed either as part of R&D projects for the petroleum industry or in the course of major reservoir studies. Leading-edge visco-elasto-plastic rheological laws are in particular available for clastic rocks, shales, chalk and rock salt.
The validity of the available code and modeling approach that the RTI follows is internationally recognized by various publications and proceedings of international conferences [e.g. Plischke, 1994; Plischke and Bulgakov, 1998; Willson et al., 1999; Christensen et al., 2004; Plischke et al., 2004; Plischke and Cassiani, 2005; Kristiansen and Plischke, 2010; Cassiani et al., 2017; ].
Please contact one of our experts to discover more about the Isamgeo FE Simulator and its unique capabilities.