Simulation and visualization of near-well flow

The ability to understand and optimize the exact circumstances by which fluids enter the wellbore is increasingly crucial to achieving effective and economic production. The well completion, the connection to the reservoir, must be designed and operated in accordance with the true physics of the near well flow environment. The ability to visualize such flows, then parameterize and extrapolate the results with realistic simulation models, affords a powerful advantage in creating well completions that are simple to install, reliable to operate, and, of course, deliver all the flow the reservoir is capable of yielding. This paper illustrates the use of advanced visualization in this process. Two examples are presented, featuring detailed images of flow through complex sand control completions hardware (gravel pack) and of flow through wormholes in acid-stimulated carbonate rock. For the first case, a new approach is presented for the non-invasive visualization of flow patterns in a modeled a gravel pack completion using magnetic resonance imaging (MRI) with a whole-body clinical 3-Tesla scanner. Advanced MRI pulse sequences for structural imaging and for flow visualization were utilized to measure flow velocities in the gravel pack model. Its geometry was men visualized by three-dimensional surface reconstruction methods and the highly resolved three-dimensional velocity field allowed for the calculation of flow streamlines through the entire completion. Thus, the effect of each component of the completion can be fully characterized and a redesign of the completion hardware targeting flow optimization can be envisioned. Beyond the importance of opening a novel window on the fluid dynamics research of completion hardware, this application also demonstrates a successful technological synergy between the energy industry and the medical research, as well as a recognition of the value of the Pumps and Pipes workshop with the Methodist DeBakey Heart & Vascular Center, under which this interdisciplinary collaboration was originated. For the second case, a combination of experimental, imaging, and computational modeling techniques is employed to better understand the structures and fluid flow impacts of wormhole networks formed during carbonate matrix acidizing. Large-scale acidizing experiments have been conducted on quarried carbonate rock samples including variation of several system characteristics such as completion type, saturating fluid, rock type, and acid injection rate. Here, a subset of these experiments are referenced to explain the process of obtaining detailed digital visualization of the internal void space structure formed during acidizing. The discussion then extends to utilization of this digital image data for Computational Fluid Dynamics (CFD) modeling of fluid flow associated with the wormhole networks.