Capillary Pressure and Wettability Indications of Middle Bakken Core Plugs for Improved Oil Recovery
- Somayeh Karimi (Colorado School of Mines) | Hossein Kazemi (Colorado School of Mines) | Gary Simpson (Hess Corporation)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- February 2019
- Document Type
- Journal Paper
- 310 - 325
- 2019.Society of Petroleum Engineers
- Oil Recovery, Capillary Pressure, Preserved Middle Bakken Cores, Molecular diffusion, Nuclear Magnetic Resonance
- 21 in the last 30 days
- 322 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
Understanding reservoir-rock characteristics and the forces that mobilize oil in unconventional reservoirs is critical in designing oil-recovery schemes. Thus, we conducted laboratory experiments for three preserved Middle Bakken cores using centrifuge and nuclearmagnetic-resonance (NMR) instruments to understand oil-recovery mechanisms in the Bakken. Specifically, we measured capillary pressure, pore-size distribution (PSD), and oil and brine saturations and distributions.
A series of oil/brine-replacement experiments (drainage and imbibition) were conducted for the preserved cores using a high-speed centrifuge. T2 time distribution and 1D saturation-profile measurements were obtained using a 2-MHz NMR instrument before and after centrifuge experiments. Moreover, PSD was determined from mercury-intrusion capillary pressure (MICP) and nitrogen-gas-adsorption experiments. We conducted scanning-electron-microscope (SEM) imaging on polished cubical cores to determine pore shapes and mineralogy of pore walls using a field-emission SEM (FE-SEM).
Our measurements show that these three preserved Middle Bakken cores show mixed-wet characteristics. Water resides in smaller pores and oil resides in larger pores in all experiments. Using a low-salinity synthetic brine of 50,000 ppm to surround Bakken cores of much-higher salinity, we produced up to 6.33% [of pore volume (PV)] oil from two higher-porosity (approximately 8%) cores, and 10.72% (of PV) oil from one lower-porosity (approximately 2%) core in a spontaneous-imbibition (SI) experiment. Up to 6.62% (of PV) oil from the two higher-porosity cores and 11.23% (of PV) oil from the lower-porosity core were produced in a forced-imbibition (FI) experiment as well. These experiments indicate that molecular diffusion/capillary osmosis overrides the wettability effects in low-permeability Middle Bakken cores. The new observations regarding molecular diffusion/capillary osmosis have altered our classical notion of capillary imbibition in low-permeability reservoirs.
|File Size||2 MB||Number of Pages||16|
Al Hinai, A., Rezaee, R., Esteban, L. et al. 2014. Comparisons of Pore Size Distribution: A Case from the Western Australian Gas Shale Formations. J. Unconven. Oil Gas Resour. 8 (December): 1–13. https://doi.org/10.1016/j.juogr.2014.06.002.
Amyx, J. W., Bass, D. M. Jr., and Whiting, R. L. 1960. Petroleum Reservoir Engineering—Physical Properties. TorontoMcGraw-Hill.
Anderson, W. G. 1986. Wettability Literature Survey—Part 2: Wettability Measurement. J Pet Technol 38 (11): 1246–1262. SPE-13933-PA. https://doi.org/10.2118/13933-PA.
Ayappa, K. G., Davis, H. T., Davis, E. A. et al. 1989. Capillary Pressure: Centrifuge Method Revisited. AIChE Journal 35 (3): 365–372. https://doi.org/10.1002/aic.690350304.
Barrett, E. P., Joyner, L. G., and Halenda, P. P. 1955. The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations from Nitrogen Isotherm. J. Am. Chem. Soc. 73 (1): 373–380. https://doi.org/10.1021/ja01145a126.
Butler, J. P., Reeds, J. A., and Dawson, S. V. 1981. Estimating Solution of First Kind Integral Equations With Non-Negative Constraints and Optimal Smoothing. SIAM J. Numer. Anal. 18 (3): 381–397. https://doi.org/10.1137/0718025.
Carr, H. Y. and Purcell, E. M. 1954. Effects of Diffusion on Free Precession in Nuclear Magnetic Resonance Experiments. Phys. Rev. 94 (3): 630–638. https://doi.org/10.1103/PhysRev.94.630.
Coates, G. R., Lizhei, X., and Prammer, M. G. 1999. NMR Logging Principles and Applications. Houston: Halliburton Energy Services Publication.
Donaldson, E. C., Thomas, R. D., and Lorenz, P. B. 1969. Wettability Determination and its Effect on Recovery Efficiency. SPE J. 9 (1): 13–20. SPE-2338-PA. https://doi.org/10.2118/2338-PA.
Dunn, K.-J., La Torraca, G. A., Warner, J. L. et al. 1994. On the Calculation of NMR Relaxation Time Distributions. Presented at SPE 69th Annual Technical Conference and Exhibition, New Orleans, 25–28 September. SPE 28367-MS. https://doi.org/10.2118/28367-MS.
Forbes, P. L. 1994. Simple and Accurate Methods for Converting Centrifuge Data into Drainage and Imbibition Capillary Pressure Curves. The Log Analyst 35 (4): 31–53. SPWLA-1994-v35n4a3.
Hagoort, J. 1980. Oil Recovery by Gravity Drainage. SPE J. 20 (3): 139–150. SPE-7424-PA. https://doi.org/10.2118/7424-PA.
Hassler, G. L. and Brunner, E. 1945. Measurements of Capillary Pressure in Small Core Samples. Trans. AIME 160 (1): 114–123. SPE-945114-G. https://doi.org/10.2118/945114-G.
Karimi, S. and Kazemi, H. 2017. Characterizing Pores and Pore-Scale Flow Properties in Middle Bakken Cores. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 9–11 October. SPE-187076-MS. https://doi.org/10.2118/187076-MS.
Kenyon, W. E. 1997. Petrophysical Principles of Applications of NMR Logging. The Log Analyst 38 (2): 21–43. SPWLA-1997-v38n2a4.
Lawson, C. L. and Hanson, R. J. 1974. Solving Least Squares Problems. Englewood Cliffs, New Jersey: Prentice-Hall.
Looyestijn, W. J. and Hofman, J. 2006. Wettability-Index Determination by Nuclear Magnetic Resonance. SPE Res Eval & Eng 9 (2): 146–153. SPE-93624-PA. https://doi.org/10.2118/93624-PA.
Meiboom, S. and Gill, D. 1958. Modified Spin-Echo Method for Measuring Nuclear Relaxation Times. Rev. Sci. Instrumen. 29 (8): 668–691. https://doi.org/10.1063/1.1716296.
Morrow, N. R. 1990. Wettability and its Effect on Oil Recovery. J Pet Technol 42 (12): 1476–1484. SPE-21621-PA. https://doi.org/10.2118/21621-PA.
Rajan, R. R. 1986. Theoretically Correct Analytical Solution for Calculating Capillary Pressure-Saturation from Centrifuge Experiments. Presented at SPWLA 27th Annual Logging Symposium, Houston, 9–13 June. SPWLA-1986-J.
Revil, A., Woodruff, W. F., Torres-Verdin, C. et al. 2013. Complex Conductivity Tensor of Anisotropic Hydrocarbon-Bearing Shales and Mudrocks. Geophysics 78 (6): D403–D418. https://doi.org/10.1190/GEO2013-0100.1.
Schmitt, M., Fernandes, C. P., da Cunha Neto, J. A. B. et al. 2013. Characterization of Pore Systems in Seal Rocks Using Nitrogen Gas Adsorption Combined With Mercury Injection Capillary Pressure Techniques. Mar. Petrol. Geol. 39 (1): 138–149. https://doi.org/10.1016/j.marpetgeo.2012.09.001.
Sonnenberg, S. A. 2014. The Upper Bakken Shale Resource Play, Williston Basin. Oral presentation given at the AAPG Rocky Mountain Section Meeting, Denver, 20–22 July.
Teklu, T. W., Alharthy, N., Kazemi, H. et al. 2014. Phase Behavior and Minimum Miscibility Pressure in Nanopores. SPE Res Eval & Eng 17 (3): 396–403. SPE-168865-PA. https://doi.org/10.2118/168865-PA.
van Domselaar, H. R. 1984. Exact Equation to Calculate Actual Saturations from Centrifuge Capillary Pressure Measurements. Rev. Tec. INTEVEP 4: 55–62.
Venkataramanan, L., Hurlimann, M. D., Tarvin, J. A. et al. 2014. Experimental Study of the Effect of Wettability and Fluid Saturation on Nuclear Magnetic Resonance and Dielectric Measurements in Limestone. Petrophysics 55 (6): 572–586. SPWLA-2014-v55n6a3.
Wang, D., Butler, R., Zhang, J. et al. 2012. Wettability Survey in Bakken Shale With Surfactant-Formulation Imbibition. SPE Res Eval & Eng 15 (6): 695–705. SPE-153853-PA. https://doi.org/10.2118/153853-PA.