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Thursday, March 6 • 4:30pm - 6:30pm
Poster: An Efficient Numerical Algorithm for Flash Calculations with Graphic Processor Units (GPU) in Compositional Reservoir Simulations, Guan Qin, University of Houston

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Light oil and gas condensate reservoirs, as well as some enhanced oil recovery processes, usually exhibate complicated phase behavior that invovles the significant changes in fluid compositions through their production life cycle. Numerical modeling of such reservoirs requires compositional simulation that solves coupled problem of multi-phase and multi-component flow and mass exchanges among different phases. Equation of State (EOS) based flash calculation is usually employed for the calculation of phase partition of the fluid compostion in compositional simulation and could consume up to 40% of the total simulation time. Such a significant computational cost should be considered and mitigated in the implementation of the compositional simulation in parallel computing architectures. The recent breakthrough in the utilization of graphical processing unit (GPU) as a highly parallel programmable processor provides a low-cost high performance parallel computing platform. In this paper, we have proposed and developed a GPU-based algorithm for the EOS based flash calculation to improve the numerical efficiency of compositional simulations. EOS based flash calculations involve various types of data and operations. By exploiting dataflow nature of the flash calculation algorithm, the number of external references can be reduced due to better caching behavior and data reusability, and the memory bandwidth bottleneck can be alleviated. We first optimized the simulation code to reduce the overall operation counts. In addition, a new data structure was designed and implemented to achieve coalesced access to the global memory. Further optimization work was done for better utilizing the constant memory, the shared memory and the registers on GPUs, based on data characteristics. Three compositional simulation cases, including refined SPE3 and SPE5 cases, were tested. We achieved speedup factors from 15.4 to 24.9 for the flash calculation and successfully reduces the cost of the flash calculations to a trivial level, 1%~2% of the total computational time.


Thursday March 6, 2014 4:30pm - 6:30pm PST
BRC Exhibit Hall Rice University 6500 Main Street at University, Houston, TX 77030