A large-scale laboratory for testing a wide range of petroleum recovery and geomechanical processes has been designed and built to provide a test bed for understanding processes before proceeding to field-scale trials of new technology. The system, dubbed LARGE for Large-scale Apparatus for Reservoir and Geomechanical Experimentation, is centered around a 50 ton, 2100 psi rated pressure vessel that allows testing of processes on a “physical model” of the reservoir that is 210 cm in diameter and up to 50 cm thick. Key specifications for the system include an “overburden” spacer to mimic the deformation of the real overburden on the reservoir, pumps and “feed” vessels to simulate injection and production in up to 10 wells, over 450 sensors to measure and image real-time the progress of processes occurring in the vessel, a cooling and heating system to control the temperature of the sandpack between -30 ºC and +90 ºC, and a computer-controlled lab control system to automatically run most processes and collect and process huge amounts of data. They system can be used for a wide range of processes but early work will focus on reservoir processes in shallow, heavy oil reservoirs and overpressured unconsolidated sand reservoirs.
Laboratory testing of petroleum reservoir processes, especially under full geomechanical conditions, is often confined to the core-scale (1” to 4” diameter). Limited information can be gained by testing processes and systems at the sub-meter scale for the understanding of processes that operate at the 10-1000 m scale in the field. As such many have tried to increase the scale at which tests can be done in the laboratory before proceeding to field testing concepts and processes (Block et al., 2000; Casas et al. 2006; Guo et al., 2000; Holder et al, 1993; Kosar and Been, 1989; Suarez-Rivera et al, 2002). Although several large-scale (1 m and up) apparatus have been constructed for studying various phenomena, they are most often limited by several factors: the range of reservoir conditions they can reproduce (especially stresses and temperatures), the geometry of system and boundary conditions they simulate (long rectangular geometries for studying perforating, one-dimensional fluid flow in long core floods, half- circle geometries for near-wellbore sand flow), or the degree they can reproduce the reservoir conditions (generally, the larger they system, the lower the stresses and pressures it can operate at). Geometry, boundary conditions, and cost often limit the number of sensors and overall instrumentation that accompany large-scale lab systems. However, the need remains to better understand a range of reservoir processes and the impact of geomechanics at the large-scale in the laboratory before proceeding to test in the field. Two of the most critical needs are the ability to test flow and deformation processes in threedimensions at full reservoir conditions (including stress) with sufficient instrumentation to fully understand the process and the ability to test at a large enough scale so that reasonable geologic heterogeneity can be incorporated in the “physical model” of the reservoir.
