Experimental Reproduction of Wettability for Core Analysis


Panagiotis Aslanidis


core analysis, wettability, fluid flow, porous media, reservoir sandstone


The ideal scenario when core samples are retrieved from the field to the lab is to start the experiment immediately without any treatment. Due to a decrease in pressure and temperature from reservoir to standard conditions, fluid expansion occurs. The depressurized cores will not have a correct fluid saturation and need to be restored prior to laboratory core experiments. To achieve representative reservoir data from these tests, the restored core wettability needs to be close to reservoir conditions.

Wettability dictates the fluid flow in porous media, and the restored wettability will dramatically influence the results on capillary pressure, relative permeability, and oil recovery tests in laboratory experiments. Therefore, wettability should be preserved in-between restoration processes.

The wettability of a core retrieved in the lab can be affected during cleaning and restoration procedures. A wide range of cleaning techniques are followed in laboratories including different solvents, experimental set-ups, methods, etc. The same applies in core restoration, where the restoring protocol differs from one lab to another including establishing initial water saturation, crude oil exposure, the aging process, etc.

In this project, several reservoir sandstone and outcrop carbonate cores, underwent a series of experiments in regard to wettability. The solvents utilized during core cleaning and the amount of crude oil exposed to the core during core restoration were the study's major emphasis. In this work, two cleaning procedures were compared: a mild approach (kerosene and heptane) and a more rigorous industrial standard used (toluene/methanol). Amount of, 1, 5, and 11 pore volumes (PV) of crude oil was utilized to evaluate the effect of crude oil exposure in the wettability of a system. Finally, an adsorption test on a sandstone reservoir core was performed to provide more thorough monitoring of the influence of crude oil in the sandstone rock surface.

The findings indicated that mild cleaning followed by an uncontrolled quantity of crude oil exposure might have a substantial influence on the wettability of the system, causing it to become less water-wet. A more comprehensive adsorption test on the reservoir sandstone core demonstrated that polar organic components (POC) continue to adsorb on the mineral surface even after many PV injections. However, the use of more rigorous solvents resulted in the reverse situation, resulting in more water-wet conditions. Finally, the use of mild solvents with just 1 PV of crude had no effect on the wettability of the systems between restorations.

In conclusion, this doctoral thesis proposes an efficient core cleaning and restoration process in which the wettability of the cores is replicated from one restoration to the next.

Author Biography

Panagiotis Aslanidis

PhD fellow
Faculty of Science and Technology
Department of Energy Resources
University of Stavanger


Aghaeifar, Z., Strand, S., Austad, T., Puntervold, T., Aksulu, H., Navratil, K., Storås, S., & Håmsø, D. (2015). Influence of Formation Water Salinity/Composition on the Low-Salinity Enhanced Oil Recovery Effect in High-Temperature Sandstone Reservoirs. Energy & Fuels, 29(8), 4747-4754.


Aghaeifar, Z., Strand, S., & Puntervold, T. (2019). Significance of Capillary Forces during Low-Rate Waterflooding. Energy & Fuels, 33(5), 3989-3997.


Al-Maamari, R. S. H., & Buckley, J. S. (2000). Asphaltene Precipitation and Alteration of Wetting: Can Wettability Change during Oil Production? Paper presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, Oklahoma.


Amott, E. (1959). Observations Relating to the Wettability of Porous Rock. Transactions of the AIME, 216(01), 156-162.


Andersen, P. Ø., Wang, W., Madland, M. V., Zimmermann, U., Korsnes, R. I., Bertolino, S. R. A., Minde, M., Schulz, B., & Gilbricht, S. (2018). Comparative Study of Five Outcrop Chalks Flooded at Reservoir Conditions: Chemo-mechanical Behaviour and Profiles of Compositional Alteration. Transport in Porous Media, 121(1), 135-181.


Anderson, W. (1986). Wettability Literature Survey- Part 1: Rock/Oil/Brine Interactions and the Effects of Core Handling on Wettability. Journal of Petroleum Technology, 38(10), 1125- 1144.


Anderson, W. (1986). Wettability Literature Survey- Part 2: Wettability Measurement. Journal of Petroleum Technology, 38(11), 1246- 1262.


Anderson, W. (1986). Wettability Literature Survey-Part 3: The Effects of Wettability on the Electrical Properties of Porous Media. Journal of Petroleum Technology, 38(12), 1371-1378.


Anderson, W. (1987). Wettability Literature Survey- Part 4: Effects of Wettability on Capillary Pressure. Journal of Petroleum Technology, 39(10), 1283-1300.


Anderson, W. (1987). Wettability Literature Survey Part 5: The Effects of Wettability on Relative Permeability. Journal of Petroleum Technology, 39(11), 1453-1468.


Andersson, M. P., Hem, C. P., Schultz, L. N., Nielsen, J. W., Pedersen, C. S., Sand, K. K., Okhrimenko, D. V., Johnsson, A., & Stipp, S. L. S. (2014). Infrared Spectroscopy and Density Functional Theory Investigation of Calcite, Chalk, and Coccoliths-Do We Observe the Mineral Surface? The Journal of Physical Chemistry A, 118(45), 10720-10729.


API. (1998). Recommended Practices for Core Analysis (Vol. SECOND EDITION): API Publishing Services.

Aslanidis, P., Strand, S., Pinerez Torrijos, I. D., & Puntervold, T. (2021). Reproducing wettability in sandstone reservoir core material in laboratory core restorations. Journal of Petroleum Science and Engineering, 109531.


Austad, T., Rezaeidoust, A., & Puntervold, T. (2010). Chemical Mechanism of Low Salinity Water Flooding in Sandstone Reservoirs. Paper presented at the SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, USA.


Bertolino, S., Zimmermann, U., Madland, M., Hildebrand-Habel, T., Hiorth, A., & Korsnes, R. (2013). Mineralogy, geochemistry and isotope geochemistry to reveal fluid flow process in flooded chalk under long term test conditions for EOR purposes. Paper presented at the XV International Clay Conference, Brasil.

Blatt, H. T. R. J. (2001). Petrology : igneous, sedimentary, and metamorphic. New York, NY: Freeman.

Block, A. a. S., B.B. (1967). Desorption and Exchange of Adsorbed Octadecylamine and Stearic Acid on Steel and Glass. J. Colloid Interface Sci, 514-518.


Borre, M. K., & Coffey, B. P. (2014). Multi-stage Cleaning for Routine Core Analysis in Heavy Oil-bearing Carbonates, Campos Basin, Brazil.


Bovet, N., Yang, M., Javadi, M. S., & Stipp, S. L. S. (2015). Interaction of alcohols with the calcite surface. Physical Chemistry Chemical Physics, 17(5), 3490-3496.


Brady, P. V., Bryan, C. R., Morrow, N. R., & Fogden, A. (2015, 2015- 10-01). pH and the low salinity effect, United States.

Buckley, Liu, Y., & Monsterleet, S. (1998). Mechanisms of Wetting Alteration by Crude Oils. SPE Journal, 3(01), 54-61.


Buckley, J. (1995). Asphaltene Precipitation and Crude Oil Wetting. SPE Advanced Technology Series, 3(01), 53-59.


Buckley, J. (1995). Crude oils can alter rock wettabilitu with or without precipitation of asphaltenes. SPE Advanced Technology Series, Vol. 3, No. 1, 53-59.


Buckley, J., & Liu, Y. (1998). Some mechanisms of crude oil/brine/solid interactions. Journal of Petroleum Science and Engineering, 20(3), 155-160.


Buckley, J., & Morrow, N. R. (1990). Characterization of Crude Oil Wetting Behavior by Adhesion Tests. Paper presented at the SPE/DOE Enhanced Oil Recovery Symposium.


Buckley, J., Takamura, K., & Morrow, N. R. (1989). Influence of Electrical Surface Charges on the Wetting Properties of Crude Oils. SPE Reservoir Engineering, 4(03), 332-340. doi:10.2118/16964-PA


Castellan, G. W. (1979). Physical Chemistry. Reading, Massachusetts: Addison-Wesley Publishing Company.

Clayfield, E. J., & Smith, A. L. (1970). Adhesion and detachment of solid colloidal particles in aqueous ionogenic surfactant media. Environmental Science & Technology, 4(5), 413-416.


Conley, F. R., & Burrows, D. B. (1956). A Centrifuge Core Cleaner. Journal of Petroleum Technology, 8(10), 61-62.


Crocker, M. E., & Marchin, L. M. (1988). Wettability and Adsorption Characteristics of Crude-Oil Asphaltene and Polar Fractions. Journal of Petroleum Technology, 40(04), 470-474.


Cuiec. (1975). Restoration of the Natural State of Core Samples. Paper presented at the Fall Meeting of the Society of Petroleum Engineers of AIME, Dallas, Texas.


Cuiec. (1984). Rock/Crude-Oil Interactions and Wettability: An Attempt To Understand Their Interrelation. Paper presented at the SPE Annual Technical Conference and Exhibition.


Dean, E. W., & Stark, D. D. (1920). A Convenient Method for the Determination of Water in Petroleum and Other Organic Emulsions. Journal of Industrial & Engineering Chemistry, 12(5), 486-490.


Donaldson, E., & Alam, W. (2008). Wettability. Houston: Gulf Publishing Company.


Fabricius, I. L., & Borre, M. K. (2007). Stylolites, porosity, depositional texture, and silicates in chalk facies sediments: Ontong Java Plateau - Gorm and Tyra fields, North Sea. Sedimentology, 54, 183-205.


Fan, T., & Buckley, J. S. (2007). Acid Number Measurements Revisited. SPE Journal, 12(04), 496-500.


Fatemi, S. M., Sohrabi, M., Jamiolahmady, M., & Ireland, S. (2012). Recovery Mechanisms and Relative Permeability for Gas/Oil Systems at Near-miscible Conditions: Effects of Immobile Water Saturation, Wettability, Hysteresis and Permeability. Paper presented at the SPE Improved Oil Recovery Symposium.


Fathi, S. J., Austad, T., & Strand, S. (2010). "Smart Water" as a Wettability Modifier in Chalk: The Effect of Salinity and Ionic Composition. Energy & Fuels, 24(4), 2514-2519.


Fathi, S. J., Austad, T., & Strand, S. (2011). Water-Based Enhanced Oil Recovery (EOR) by "Smart Water": Optimal Ionic Composition for EOR in Carbonates. Energy & Fuels, 25(11), 5173-5179.


Fernø, M. A., Grønsdal, R., Åsheim, J., Nyheim, A., Berge, M., & Graue, A. (2011). Use of Sulfate for Water Based Enhanced Oil Recovery during Spontaneous Imbibition in Chalk. Energy & Fuels, 25(4), 1697-1706.


Frykman, P. (2001). Spatial variability in petrophysical properties in Upper Maastrichtian chalk outcrops at Stevns Klint, Denmark. Marine and Petroleum Geology, 18(10), 1041-1062.


Gant, P. L., & Anderson, W. G. (1988). Core Cleaning for Restoration of Native Wettability. SPE Formation Evaluation, 3(01), 131-138.


Gaudin, & Chang, A. M., and C.S. (1952). Adsorption on Quartz, From an Aqueous Solution, of Barium and Laurate Ions. AIME-Mining Engineering, 193-201.

Gaudin, & Fuerstenau, D. (1955). Quartz flotation with Anionic Collectors. AIME-Mining Engineering, 66-72.

Grist, D. M., Langley, G. O., & Neustadter, F. L. (1975). The Dependence of Water Permeability On Core Cleaning Methods In the Case of Some Sandstone Samples. Journal of Canadian Petroleum Technology, 14(02).


Guedez, A., Govindarajan, S., Lambert, D., Keyes, S., Patterson, R., Mickelson, W., Mitra, A., Aldin, S., Gokaraju, D., Thombare, A., & Aldin, M. (2020). An Integrated Geomechanical, Petrophysical and Petrographical Study to Evaluate the Efficacy of a Plug Cleaning Technique for Ultra-Low Permeability Rocks. Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Virtual.


Gupta, & Mohanty, K. K. (2008). Wettability Alteration of Fractured Carbonate Reservoirs. Paper presented at the SPE Symposium on Improved Oil Recovery.


Gupta, Rai, C., Tinni, A., & Sondergeld, C. (2017). Impact of Different Cleaning Methods on Petrophysical Measurements. Petrophysics- The SPWLA Journal of Formation Evaluation and Reservoir Description, 58(06), 613-621.

He, L., Lin, F., Li, X., Sui, H., & Xu, Z. (2015). Interfacial sciences in unconventional petroleum production: from fundamentals to applications. Chemical Society Reviews, 44(15), 5446-5494.


Hjuler, M. L., & Fabricius, I. L. (2009). Engineering properties of chalk related to diagenetic variations of Upper Cretaceous onshore and offshore chalk in the North Sea area. Journal of Petroleum Science and Engineering, 68(3), 151-170.


Hodder, K. J., & Nychka, J. A. (2019). Silane Treatment of 3D-Printed Sandstone Models for Improved Spontaneous Imbibition of Water. Transport in Porous Media, 129(2), 583-598.


Hopkins, P. (2017). Water-Based EOR and Initial Wettability in Carbonates. (Doctorate Ph.D. thesis). University of Stavanger, Stavanger. (329)

Hopkins, P., Omland, I., Layti, F., Strand, S., Puntervold, T., & Austad, T. (2017). Crude Oil Quantity and Its Effect on Chalk Surface Wetting. Energy & Fuels, 31.


Hopkins, P., Walrond, K., Strand, S., Puntervold, T., Austad, T., & Wakwaya, A. (2016). Adsorption of Acidic Crude Oil Components onto Outcrop Chalk at Different Wetting Conditions during Both Dynamic Adsorption and Aging Processes. Energy & Fuels, 30(9), 7229-7235.


Hopkins, P. A., Strand, S., Puntervold, T., Austad, T., Dizaj, S. R., Waldeland, J. O., & Simonsen, J. C. (2016). The adsorption of polar components onto carbonate surfaces and the effect on wetting. Journal of Petroleum Science and Engineering, 147, 381-387.


Jahanbakhsh, A., Shahverdi, H., & Sohrabi, M. (2016). Gas/Oil Relative Permeability Normalization: Effects of Permeability, Wettability, and Interfacial Tension. SPE Reservoir Evaluation & Engineering, 19(04), 673-682.


Jennings, H. Y., Jr. (1957). Effect of Laboratory Core Cleaning on Water-Oil Relative Permeability.


Jiang, Y., Lian, J., Jiang, Z., Li, Y., & Wen, C. (2020). Thermodynamic analysis on wetting states and wetting state transitions of rough surfaces. Advances in Colloid and Interface Science, 278, 102136.


Johansen, R. T., & Dunning, H. N. (1959). Relative wetting tendencies of crude oils by the capillarimetric method. Producers Monthly, 23(11), 20-22.

Kaminsky, R., & Radke, C. J. (1997). Asphaltenes, Water Films, and Wettability Reversal. SPE Journal, 2(04), 485-493.


Mamonov, Kvandal, O. A., Strand, S., & Puntervold, T. (2019). Adsorption of Polar Organic Components onto Sandstone Rock Minerals and Its Effect on Wettability and Enhanced Oil Recovery Potential by Smart Water. Energy & Fuels, 33(7), 5954-5960.


Mamonov, A. (2019). EOR by Smart Water Flooding in Sandstone Reservoirs-Effect of Mineralogy on Rock Wetting and Wettability Alteration. (Doctorate PhD Thesis). University of Stavanger, Stavanger. (468)

Mamonov, A., Puntervold, T., Strand, S., Hetland, B., Andersen, Y., Wealth, A., & Nadeau, P. H. (2020). Contribution of Feldspar Minerals to pH during Smart Water EOR Processes in Sandstones. Energy & Fuels, 34(1), 55-64.


McCaffery, F. G. a. M., N. (1970). Contact Angle and Interfacial Tension Studies of Some Hydrocarbon-Water-Solid systems. J. Cdn. Pet. Tech., 185-196.


Megawati, M., Madland, M. V., & Hiorth, A. (2015). Mechanical and physical behavior of high-porosity chalks exposed to chemical perturbation. Journal of Petroleum Science and Engineering, 133, 313-327.


Morrow, N. R. (1990). Interfacial Phenomena. New Mexico: MARCEL DEKKER, INC.

Newgord, C., Garcia, A. P., & Heidari, Z. (2019). A New Workflow for Joint Interpretation of Electrical Resistivity and NMR Measurements to Simultaneously Estimate Wettability and Water Saturation. Paper presented at the SPWLA 60th Annual Logging Symposium.


Pinerez, I. D. (2017). Enhanced oil recovery from Sandstones and Carbonates with "Smart Water". (Doctor of Philosophy). University of Stavanger, Stavanger, Norway. Retrieved from https://uis.brage.unit.no/uis-xmlui/handle/11250/2453447 (978-82-7644-708-8)

Puntervold, T., Mamonov, A., Aghaeifar, Z., Frafjord, G. O., Moldestad, G. M., Strand, S., & Austad, T. (2018). Role of Kaolinite Clay Minerals in Enhanced Oil Recovery by Low Salinity Water Injection. Energy & Fuels, 32(7), 7374-7382.


Puntervold, T., Mamonov, A., Piñerez Torrijos, I. D., & Strand, S. (2021). Adsorption of Crude Oil Components onto Carbonate and Sandstone Outcrop Rocks and Its Effect on Wettability. Energy & Fuels.


Puntervold, T., Strand, S., & Austad, T. (2007). Water flooding of carbonate reservoirs: effects of a model base and natural crude oil bases on chalk wettability. Energy & Fuels, 21(3), 1606-1616.


Rao, D. N. (1999). Wettability Effects in Thermal Recovery Operations. SPE Reservoir Evaluation & Engineering, 2(05), 420-430.


RezaeiDoust, A. (2011). Low Salinity Water Flooding in Sandstone Reservoirs-A Chemical Wettability Alteration Mechanism. Stavanger: University of Stavanger.

RezaeiDoust, A., Puntervold, T., & Austad, T. (2011). Chemical Verification of the EOR Mechanism by Using Low Saline/Smart Water in Sandstone. Energy & Fuels, 25(5), 2151-2162.


Røgen, B., & Fabricius, I. L. (2002). Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea. Petroleum Geoscience, 8(3), 287-293.


Schlumberger. (1998, 2022). Oilfield Glossary. Retrieved from https://glossary.oilfield.slb.com/

Shariatpanahi, F., Strand, S., Austad, T., & Aksulu, H. (2012). Wettability Restoration of Limestone Cores Using Core Material From the Aqueous Zone. Petroleum Science and Technology - PET SCI TECHNOL, 30, 1082-1090.


Skovbjerg, L. L., Hassenkam, T., Makovicky, E., Hem, C. P., Yang, M., Bovet, N., & Stipp, S. L. S. (2012). Nano sized clay detected on chalk particle surfaces. Geochimica et Cosmochimica Acta, 99, 57-70.


Skovbjerg, L. L., Okhrimenko, D. V., Khoo, J., Dalby, K. N., Hassenkam, T., Makovicky, E., & Stipp, S. L. S. (2013). Preferential Adsorption of Hydrocarbons to Nanometer-Sized Clay on Chalk Particle Surfaces. Energy & Fuels, 27(7), 3642- 3652.


Speight, J. G. (1999). The Chemistry and Technology of Petroleum: CRC Press.


Springer, N., Korsbech, U., & Aage, H. K. (2003). Resistivity index measurement without the porous plate: A desaturation technique based on evaporation produces uniform water saturation profiles and more reliable results for tight North Sea chalk. Paper presented at the Paper presented at the International Symposium of the Society of Core Analysts Pau, France.

Standnes, D. C., & Austad, T. (2000). Wettability alteration in chalk. 1. Preparation of core material and oil properties. Journal of Petroleum Science and Engineering, 28(3), 111-121.


Standnes, D. C., & Austad, T. (2003). Wettability alteration in carbonates: Interaction between cationic surfactant and carboxylates as a key factor in wettability alteration from oil-wet to water-wet conditions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 216(1), 243-259.


Strand. (2005). Wettability alteration in chalk. Stavanger: University of Stavanger.

Strand, & Puntervold, T. (2019). Recent Updates on Smart Water EOR in Limestone. Paper presented at the Offshore Technology Conference Brasil.


Strand, Standnes, D. C., & Austad, T. (2006). New wettability test for chalk based on chromatographic separation of SCN- and SO42-. Journal of Petroleum Science and Engineering, 52, 187-197.


Strand, S., Hjuler, M. L., Torsvik, R., Pedersen, J. I., Madland, M. V., & Austad, T. (2007). Wettability of chalk: impact of silica, clay content and mechanical properties. Petroleum Geoscience, 13(1), 69.


Stumm, W. a. M., J.J. (1970). Aquatic Chemistry. New York City: J. Wiley and Sons.

Wang, W., & Gupta, A. (1995). Investigation of the Effect of Temperature and Pressure on Wettability Using Modified Pendant Drop Method. Paper presented at the SPE Annual Technical Conference and Exhibition.


Wikipedia. (2001). Wikipedia. Retrieved from https://www.wikipedia.org/

Xie, Q., Ma, D., Wu, J., Liu, Q., Jia, N., & Luo, M. (2015). Low Salinity Waterflooding in Low Permeability Sandstone: Coreflood Experiments and Interpretation by Thermodynamics and Simulation. Paper presented at the SPE Asia Pacific Enhanced Oil Recovery Conference.


Zhang, & Austad, T. (2005). The relative effects of acid number and temperature on chalk wettability. Paper presented at the Paper SPE 92999 presented at the SPE International Symposium on Oilfield Chemistry, Houston, TX, USA.


Zhang, Tweheyo, M. T., & Austad, T. (2007). Wettability alteration and improved oil recovery by spontaneous imbibition of seawater into chalk: Impact of the potential determining ions Ca2+, Mg2+, and SO42−. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 301(1), 199-208.


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