1.3 Distribution of residual oil of water in emptiness of hydrophilic and hydrophobic collectors

Prospects of working out of the oil deposits which have entered a late stage at high obvodnennosti extracted production of chinks, are connected, basically, with extraction of residual oil after zavodnenija.

Researches of domestic and foreign experts M.L.Surgucheva, I.L.Marhasina, J.V.Zheltova, N.N.Mihajlova, B.N.Tulbovicha, P.N.Zabrodina, A.G.Kovaleva, V.M.Berezina, V.G.Panteleeva, Tejbera, Melrouza and dr [15,37] have filled up the general representations about forms of existence of residual oil and its principles doizvlechenija.

The oil, concentrated in the intervals of a productive layer washed out by water differ the raised maintenance of the heavy acidifyed components (asphaltenes, resins, hetero-ring compounds, etc.). Two various forms of existence of this oil depending on wettability of rock Thus distinguish:

Rock is moistened with water - the hydrophilic environment;

Rock is moistened with oil - the hydrophobic environment.

If breeds hydrophilic water occupies small and subcapillary pores, and in large pores water covers a surface in the form of films. Oil remains mainly in the form of drops (globules) which occupy both large and sredchie pores, and channels. In process zavodnenija hydrophilic and hydrophobic collectors prove various image. Replacement of oil from hydrophilic collectors rather effectively since transition zones of a diphasic filtration have the insignificant sizes, petrosaturation in the washed out zone is not enough and practically invariably in time, the basic oil recovery occurs during the anhydrous period. At zakachke waters or movement of sheet water are displayed two mechanisms of extraction of oil: capillary soaking and hydraulic replacement.

For hydrophobic layers a pattern return - transition zones occupy all layer, petrosaturation of the washed out zone is great and very gradually decreases in process zavodnenija, the basic volume of oil is extracted during the aqueous period of operation.

If breed hydrophobic oil occupies small pores and channels, and in large pores is in a kind of the films, which thickness much more, than water films. Therefore many narrowings of channels are overlaped by oil and water occupies large and mean holes, but unlike a hydrophilic collector does not represent a continuous phase, and forms chains of droplets. Zakachivaemaja water squeezes out oil which in turn pushes droplets of water towards extracting chinks from narrowings of channels. Working out process is characterised by the short periods of anhydrous extraction. And process obvodnenija an extracted liquid occurs sluggishly in time. The basic oil recovery is necessary for the aqueous period of working out.

Technologies of extraction of residual oil, obviously, in strong degree depend on pore sizes of breed of its wettability. At zavodnenii oil layers with additives of various active reagents in the petrosated breed irreversible processes, such as start to develop:

Shearing and breakoff of globules of oil;

Sticking of globules and their crushing;

Oil diffusion;

Sorption of components of petroinvading fluids on a rock surface;

Mechanical changes of volume of pores of breed at increase or

Pressure reduction in liquids containing in them and gases.

According to equation Laplasa, capillary tension Rk interfering replacement of oil from pores, is equal:

PK = PH-Pe = QeJeH (1.3.1)

Where Rn-rv - hydrostatic pressure in oil and water solution;

QBH - interfacial tension on border water solution - oil, nanometer/m;

1вн - the meniscus curvature, dividing aqueous and oil phases. In a general view on phase boundaries there are the meniscuses creating capillary tensions:


Where Rr effective radiuses of curvature of meniscuses;

p - number of meniscuses.

In a motionless condition opposite directed pressure of meniscuses are compensated, but at replacement of oil by water under the influence of external pressure meniscuses distort under the elasticity law so, that there is the component of capillary tension directed counterly to a stream (effect ZHamena):

\ R> RJ j


Where Ri and Rj - effective radiuses of curvature convex and bent (to a stream) meniscuses accordingly.

Foreign experts (Tejber, Melrouz, Brander, Lefert dju Rot, Bardon and the Longeron) investigated influence of capillary number on decrease residual neftenosnosti.

Capillary number:

Where г\в - viscosity of invading water;

U - peripheral speed; t - porosity of a layer;

Q - free superficial energy of borders has undressed oil-water.

For achievement of significant decrease in a residual petrosaturation To should be not less than 1.10"3 in comparison with usual zavodneniem (1-Ю ' 6). It can be reached or interfacial tension falloff (Q) on borders oil-water (in 100 times), or sharp increase in filtration rate or at the expense of increase in viscosity of invading fluids has undressed.

For removal from a surface of breeds of the hydrophobic residual oil kept by adhesive forces, it is necessary to perform the work counted on equation Djupre:

Wa-Q + f&n-QJ (1-3)

Where Wa - work on removal of film oil from unit of a surface of pores;

Q, Qem QHn - accordingly superficial energy of partition of phases oil, water, water - breed, oil - breed.

For effective extraction of residual oil significant reduction of free superficial energy by borders is necessary oil-water and hydrophobic interactions on border oil-breed that promotes breakoff and conduction of globules of oil in a stream has undressed.

For effective extraction of film oil it is necessary to use invading fluids with high superficial activity in volumes of hydrophobic breeds, and in case of hydrophilic breeds with mobile neftjami to these requirements can satisfy effective compositions of nonionic surfactants (NPAV).

Thus, knowing about distribution of pores in the sizes, wettability and a petrosaturation of breeds can predict as a first approximation efficiency of application of technologies for extraction of residual oil. For this purpose carrying out of a complex of the physical and chemical and filtration laboratory researches allowing adequately to estimate the mechanism of formation of residual oil in concrete geologo-trade conditions and dependence of its forms from kollektorskih of properties of a layer, properties of fluids sating it is necessary, to carry out selection of effective petrosuperseding reagents and their formula.

It is necessary to notice, that physical and chemical bases of application of active chemical agents mikro residual oil are developed for extraction rather poorly. The mechanism of action of active components of petroinvading fluids is to difficult enough and difficultly giving in quantitative estimations on separate components. Till now there is no the standard theory allowing strictly enough to estimate possible effect from application of petrosuperseding reagents in concrete geologo-physical conditions of deposits.

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A source: Kozhabergenov Murat Mokanovich. Substantiation of effective technologies doizvlechenija residual oil from obvodnennyh layers on an example of XIII horizon of deposit Uzen: Dis.... A Cand.Tech.Sci.: 25.00.17. - M: RGB, 2006. 2006

More on topic 1.3 Distribution of residual oil of water in emptiness of hydrophilic and hydrophobic collectors:

  1. 1.2 Quantitative distribution of residual oil on the deposit area
  2. 1.1.4 Film residual oil
  3. 1.1.2 Is capillary-jammed residual oil
  4. 1.1.6 Residual oil at unstable replacement
  5. 4.3.4 Signs of display of properties of wettability of collectors on change of an oil recovery and obvodnenosti chinks
  6. 1.1.3 Adsorbed residual oil
  7. 1.1.5 Residual oil in deadlock pores and micronon-uniform zones
  8. 1.1 Kinds of residual oil in zavodnennyh layers
  9. 2.7 Bases of technology doizvlechenija residual oil from obvodnennyh chinks
  10. 2.6. Laboratory researches of possibility doizvlechenija micro-residual oil after zavodnenija for conditions of layers of XIII horizon of deposit Uzen