23Na and 1H NMR Relaxometry of Shale at High Magnetic Field
详细信息 查看全文
- 作者：Donghan Yang ; Ravinath Kausik
- 刊名：Energy & Fuels
- 出版年：2016
- 出版时间：June 16, 2016
- 年：2016
- 卷：30
- 期：6
- 页码：4509-4519
- 全文大小：572K
- 年卷期：0
- ISSN：1520-5029
文摘
Formation evaluation of unconventional reservoirs is challenging due to the coexistence of different phases such as kerogen, bitumen, movable and bound light hydrocarbon and water. Current low-frequency (0.05 T) nuclear magnetic resonance (NMR) laboratory and logging methods are incapable of quantitatively separating the different phases. We demonstrate the utility of high-field (9.4 T) NMR 2D T1–T2 measurements for separating hydrocarbon and the clay-interacting aqueous phases in shale based on the difference in the frequency dependence of the spin–lattice relaxation time. Furthermore, we demonstrate 23Na NMR as a promising complementary technique to conventional 1H NMR for shale fluid typing, taking advantage of the fact that sodium ions are only present in the aqueous phase. We validate high-field (9.4 T) 23Na–1H NMR relaxometry for assessing brine-filled porosity and brine salinity in various porous materials, including porous glass, conventional rocks, clays, and shale, and apply it for differentiating hydrocarbon versus aqueous components and also the clay-associated versus free water in Eagle Ford shale cores. This work lays the groundwork for developing future downhole 23Na–1H NMR logging techniques.