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New representations of wettability of oil and gas reservoirs

UDK: 622.276.031
Key words: microstructure, reservoir, hydrocarbons, wettability, capillary pressure, disjoining pressure
Authors: N.N. Mikhailov (Gubkin Russian State University of Oil and Gas, RF, Moscow), I.P. Gurbatova (PermNIPIneft Branch of LUKOIL-Engineering LLC in Perm, RF, Perm), K.A. Motorova (Lomonosov Moscow State University, RF, Moscow), L.S. Sechina (Oil and Gas Research Institute of RAS, RF, Moscow)
This paper discusses a wide range of physical and geological factors that determine the wettability of oil and gas reservoirs. Wettability is an important parameter in oil recovery as it affects relative permeability characteristics, capillary pressure, electrical properties and other characteristics of the reservoir. Neglecting the effects of wetting causes erroneous distribution of saturation in geological modeling and development of substandard forward-looking indicators in simulation. Existing types of wettability and their applications were analyzed: strongly water-wet, strongly oil-wet, neutrally wet and fractional wettability. The phenomenon of hydrophobic pore surface by adsorption of surfactants (polar) oil components in the natural hydrophilic mineral surfaces was considered. On the basis of modern ideas about the physics of microscopic processes in porous media and stages of the geological formation of deposits substantiates a type of fractional wettability –microstructural wettability in which the oil-wet and water-wet surfaces of pores and capillaries have various wettability. Hydrophobization at pores and channels forms microstructural wettability, since pores of different size, shape and mineral composition different hydrophobized and therefore have different wettability. In the process of water repellency decreases the amount of free long oil takes a different size pores and in various forms (film, meniscus, contact), change the configuration of the pore space (in the presence of hydrocarbons configuration smoothed). These phenomena lead to the need for a detailed study of the physics of water-repellency at the micro level. There is connection between pore space structure and pores form of the rock and wettability of all pores size range. Along with the identified patterns of adsorption of hydrocarbons, depending on the shape, size and distribution of pores, they also investigated the effect of mineralogical composition (composition and particle size, the presence of clay) pore surface adsorption of water and oil phases. The conclusions from these studies are that the composition of the rock also significantly affects the adsorption processes.
1. Kuz'min V.A., Mikhaylov N.N., Skibitskaya N.A., Gurbatova I.P., Motorova
K.A., Results of the electron-microscopic research on the impact
of microstructural factors of reservoir space on the oil saturation
pattern (In Russ.), Geologiya nefti i gaza = The journal Oil and Gas Geology,
2015, no. 3, pp. 34–44.
2. Mikhaylov N.N., Ostatochnoe neftenasyshchenie razrabatyvaemykh
plastov (Residual oil saturation of developed reservoirs),
Moscow: Nedra Publ., 1992, 270 p.
3. Mileshina A.G., Kalinko M.K., Safonova G.I., Izmenenie neftey pri fil'-
tratsii cherez porody (Oil change when filtering through the rocks),
Moscow: Nedra Publ., 1983, 174 p.
4. Mikhaylov N.N., Sechina L.S., Rol' adsorbirovannykh flyuidov pri otsenke
effektivnosti metodov povysheniya nefteotdachi plastov (Role
of adsorbed fluid in the evaluation of the effectiveness of enhanced
oil recovery), Proceedings of IV International Scientific Symposium
“Teoriya i praktika primeneniya metodov uvelicheniya nefteotdachi
plastov” (Theory and practice of application of enhanced oil recovery
methods ), 18–19 September 2013, Moscow: Publ. of VNIIneft',
2013, Part 2, pp. 14–17.
5. Mikhaylov N.N., Semenova N.A., Kol'chitskaya T.N., Modelling the
impact of heterogeneous wettability of reservoir to block of hydrocarbon
reserves (In Russ.), Burenie i neft', 2004, no. 4, pp. 18-20.
6. Mikhaylov N.N., Ermilov M.O., Sechina L.S., Eksperimental'noe issledovanie
smachivaemosti i analiz ee vliyaniya na fil 'tratsionno-emkostnye
svoystva produktivnykh kollektorov Neokomskoy zalezhi Novo-
Urengoyskogo i Yamburgskogo mestorozhdeniy (Experimental study
of the wettability and the analysis of its impact on reservoir properties
of productive collectors of Neocomian deposits of Novo-Urengoy
and Yamburg fields), Novosibirsk: Publ. of SB RAS, 2012, 58 p.
7. Mikhaylov N.N., Sechina L.S., Savochkina K.A., Rol' glini stykh mineralov
v obrazovanii adsorbtsionno-svyazannoy nefti (The role of clay
minerals in the formation of absorbing-bonded oil), Proceedings of International
Conference “Gliny, glinistye mineraly i sloistye materialy”
(The clays, clay minerals and laminates), Zvenigorod, 21-25 September
2009, p. 243.
8. Mikhaylov N.N., Ermilov O.M., Sechina L.S., Physicochemical peculiarities
of absorbed oil in core samples of gas condensate deposit (In
Russ.), Doklady Akademii nauk = Doklady Earth Sciences, 2016, V. 466,
no. 3, pp. 319-323.
9. Mikhaylov N.N., Dzhemesyuk A.V., Kol'chitskaya T.N., Semenova
N.A., Izuchenie ostatochnogo neftenasyshcheniya razrabatyvaemykh
plastov (The study of residual oil saturation of developed reservoirs),
Moscow: Publ. of VNIIOENG, 1990, 59 p.
10. Akhmatov A.S., Molekulyarnaya fizika granichnogo sloya (Molecular
physics of the boundary layer), Moscow: Fizmatgiz Publ., 1963,
472 p.
11. Garoff S.E., Sirota B., Sinha S.K., Stanley H.B., Chem.Phys J., The effects
of substrate roughness on ultrathin water films, 1989, V. 90 (12),
pp. 7505-7515.
12. Semenova N.A., Sechina L.S., The role of microstructural wettability
in the filtration properties of productive layers changes (In Russ.),
Vestnik TsKR Rosnedra, 2008, no. 2, pp. 44-49.
13. Al-Yousef H.Y., Lichaa P.M., Al-Kaabi A.U., Alpustun H., Wettability
Evaluation of a carbonate reservoir rock from core to pore level,
29885-MS SPE Conference Paper, 1995.
14. Mitchell A.G., Hazell L.B., Webb K.J., Wettability determination:
pore surface analysis, 20505-MS SPE Conference Paper, 1990.

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