Monitoring oil displacement processes with k-t accelerated spin echo SPI

作者：Li Ming; Xiao Dan; Romero Zeron Laura; Balcom Bruce J^*

来源：Magnetic Resonance in Chemistry, 2016, 54(3): 197-204.

DOI：10.1002/mrc.4362

• MRI
• H-1
• oil displacement
• k-t SE-SPI
• water saturation profile
• T-2 distribution
• pore scale fluid behavior
• enhanced oil recovery

Magnetic resonance imaging (MRI) is a robust tool to monitor oil displacement processes in porous media. Conventional MRI measurement times can be lengthy, which hinders monitoring time-dependent displacements. Knowledge of the oil and water microscopic distribution is important because their pore scale behavior reflects the oil trapping mechanisms. The oil and water pore scale distribution is reflected in the magnetic resonance T-2 signal lifetime distribution. In this work, a pure phase-encoding MRI technique, spin echo SPI (SE-SPI), was employed to monitor oil displacement during water flooding and polymer flooding. A k-t acceleration method, with low-rank matrix completion, was employed to improve the temporal resolution of the SE-SPI MRI measurements. Comparison to conventional SE-SPI T-2 mapping measurements revealed that the k-t accelerated measurement was more sensitive and provided higher-quality results. It was demonstrated that the k-t acceleration decreased the average measurement time from 66.7 to 20.3min in this work. A perfluorinated oil, containing no H-1, and H2O brine were employed to distinguish oil and water phases in model flooding experiments. High-quality 1D water saturation profiles were acquired from the k-t accelerated SE-SPI measurements. Spatially and temporally resolved T-2 distributions were extracted from the profile data. The shift in the H-1 T-2 distribution of water in the pore space to longer lifetimes during water flooding and polymer flooding is consistent with increased water content in the pore space.

• 出版日期2016-3