Reservoir Formation Damage Episode 2 Part 8 doc

Formation Damage by Organic Deposition 407

O BEREA SANDSTONE O100 MESH)

A DICKITE (WISCONSIN)

D DOLOMITE (DOLOCRON)

OTTAWA SAND (SUPER X. >325 MESH)

O CALCtTE (DOVER CHALK)

• KAOLIN MINERAL

• (LUTE (BEAVER'S BEND)

O ALUMINA

1000 2000

EQUILIBRIUM ASPHALTENE CONCENTRATION, ppm —•>

Figure 14-33. Adsorption isotherms for asphaltenes on clay and mineral

surfaces from toluene (Dubey and Waxman, ©1991 SPE; reprinted by per￾mission of the Society of Petroleum Engineers).

Then, assuming that all oil is in contact with the porous media, the surface

excess of species i can be expressed as:

nf = n

f

(xl — ;c(

.) : i = asphaltene or oil (14-8)

They assume that the theory is applicable for both mono- and multi-layer

adsorption.

A balance of the oil and asphaltene adsorbed over the pore surface yields:

1

n m.

(14-9)

408 Reservoir Formation Damage

0 500 1000 1500 2000 2500

A8PHALT6NE EQUILIBRIUM CONCENTRATION, ppm —*•

Figure 14-34. Hysteresis of adsorption/desorption isotherms for asphaltenes

on kaolin from toluene (Dubey and Waxman, ©1991 SPE; reprinted by

permission of the Society of Petroleum Engineers).

3 00 600 900 1200

Equilibrium concentration of asphaltenes (mg/1)

3000

Figure 14-35. Adsorption isotherm for Cerro Negro asphaltenes on inorganic

material surface from toluene at 26°C (reprinted from Journal of Fuel, Vol.

74, Acevedo, S., Ranaudo, M. A., Escobar, G., Gutierrez, L, & Ortega, P.,

"Adsorption of Asphaltenes and Resins on Organic and Inorganic Substrates

and Their Correlation with Precipitation Problems in Production Well Tubing,"

pp. 595-598, ©1995, with permission from Elsevier Science).