A Parallel Multiblock/Multidomain Approach for Reservoir Simulation

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractOur approach for parallel multiphysics and multiscale simulation uses two levels of domain decomposition: physical and computational. First, the physical domain is decomposed into subdomains or blocks according to the geometry, geology, and physics/chemistry/biology. Each subdomain represents a single physical system, on a reasonable range of scales, such as a black oil region, a compositional region, a region to one side of a fault, or a near-wellbore region. Second, the computations are decomposed on a parallel machine for efficiency. That is, we use a multiblock or macro-hybrid approach, in which we describe a domain as a union of regions or blocks, and employ an appropriate hierarchical model on each block. This approach allows one to define grids and computations independently on each block. This local grid structure has many advantages. It allows the most efficient and accurate discretization techniques to be employed in each block. The multiblock structure of the algebraic systems allows for the design and use of efficient domain decomposition solvers and preconditioners. Decomposition into independent blocks offers great flexibility in accommodating the shape of the external boundary, the presence of internal features such as faults and wells, and the need to refine a region of the domain in space or time (by treating it as a distinct block); interfacing structured and unstructured grids; and accommodating various models of multiscale and multiphysical phenomena. The resulting grid is not suited to direct application of discretization methods. We use mortar space techniques to impose physically meaningful, mass conservative, fluxmatching conditions on the interfaces between blocks.We present numerical simulations to illustrate several of these decomposition strategies, including the coupling of IMPES and fully implicit models and upscaling by varying the number of degrees of freedom on the block interfaces.

Seine: a dynamic geometry-based shared-space interaction framework for parallel scientific applications

“…More specifically, the driving application is a subsurface simulation model, which consists of a complex interaction of fluid and rock properties that evolves with time. To achieve the desired efficiency and accuracy in the representation of the different phenomena taking place in the subsurface, the simulation provides the support for different scales (multi-scale), processes (single-phase, oil-water, air-water, threephases, compositional) and algorithms or formulations (IMPES ‡ fully implicit) through a multiblock approach [12,13]. In the simulation, the oil reservoir is discretized as a series of blocks and interfaces between blocks.…”

Enabling interactive and collaborative oil reservoir simulations on the Grid

“…The IPARS framework provides all the memory management, message passing, linear solver and nonlinear solution methods, etc. [11,12].…”

“…At the beginning of the first timestep, the wellbore density required for this purpose can be obtained from (14) Since flow rates are unknown values, wellbore density cannot be directly computed from (12). The explicit form of ρ WB can be derived by combining (11) and (13).…”

“…Total flow rates from the sink must be checked with (11) to ensure the net flow of each phase out of the formation.…”

Massively parallel simulation of flow and transport in variably saturated porous and fractured media

“…By the late 1990s, the parallel-computing reservoir simulation technology was further improved [8]. Realistic field applications of parallel techniques were demonstrated with multimillion gridblock reservoir simulations [9].…”