Realistic simulation of structurally complex reservoirs (SCR) is challenging in at least three ways: (1) geological structures must be represented and discretized accurately on vastly different length scales; (2) extreme ranges and discontinuous variations of material properties have to be associated with the discretized structures and accounted for in the computations; and (3) episodic, highly transient and often localized events such as well shut-in have to be resolved adequately within the overall production history, necessitating a highly adaptive resolution of time. To facilitate numerical experiments that elucidate the emergent properties, typical states and state transitions of SCRs, an application programmer interface (API) called complex systems modelling platform (CSMP++) has been engineered in ANSI/ISO C++. It implements a geometry and process-based SCR decomposition in space and time, and uses an algebraic multigrid solver (SAMG) for the spatio-temporal integration of the governing partial differential equations. This paper describes a new SCR simulation workflow including a two-phase fluid flow model that is compared with ECLIPSE in a single-fracture flow simulation. Geologically realistic application examples are presented for incompressible 2-phase flow, compressible 3-phase flow, and pressure-diffusion in a sector-scale model of a structurally complex reservoir.

Dam-break problems involve the formation of shocks and rarefaction fans. The performance of 20 explicit numerical schemes used to solve the shallow water wave equations for simulating the dam-break problem is examined. Results from these schemes have been compared with analytical solutions to the dam-break problem with finite water depth and dry bed downstream of the dam. Most of the numerical schemes produce reasonable results for subcritical flows. Their performance for problems where there is a transition between subcritical and supercritical flows is mixed. Although many numerical schemes satisfy the Rankine-Hugoniot condition, some produce solutions which do not satisfy the entropy condition, producing nonphysical solutions. This was the case for the majority of first-order schemes examined. Numerical schemes which consider critical flow in the solution are guaranteed to produce entropy satisfying solutions. Second-order schemes avoid the generation of expansive shocks; however, some form of flux or ...

In recognition of the risks associated with the catastrophic collapse of a water supply reservoir, a computer model was developed to predict the progress of the ensuing flood. The fractional-step method is used to solve the two-dimensional shallow water wave equations on an unstructured triangular grid. The finite-volume method with a first-order approximate Riemann solver is used to solve the homogeneous equations. Euler's method is used to solve the ordinary differential equation operator. Verification of the model is achieved by comparing the model results with analytical solutions as well as documented published results with very good agreement. The model is applied to a case study involving the sudden collapse of a water supply reservoir. These reservoirs are generally located in elevated positions in residential areas, and represent a potential risk to life and property. The model is conservative, robust, efficient, and capable of simulating the wetting and drying processes. It resolves shocks, simu...