Page 59 - Reservoir Formation Damage

Mineralogy and Mineral Sensitivity of Petroleum-Bearing Formations 43

Lynn and Nasr-El-Din (1998) classified reservoir formations having less
than 1 wt. % total clay and permeability higher than one Darcy as the
high quality, and the low quality vice versa. Amaefule et al. (1993) mea-
sured the formation quality by the reservoir quality index defined as:

(2-40)

Hayatdavoudi Hydration Index (HHI)

The Hayatdavoudi hydration index (HHI=[O/OH]) is defined as the
ratio of the oxygen atoms to hydroxyl groups in clays and it controls the
enthalpy or free energy of the clays available for the work of swelling

SMECTTT E GROUP & VI RMICOUTC-*
/
/
ILUTEOf OUP&ATTAP M.GITE/
~s
s
(a)
/I
/
S
tf£ — K/ OLJN1TEGRO IP&CHLORTT
1.5
LN "HP SCALE

(b)

LN "HH" SCALE
Figure 2-28. Hayatdavoudi clay hydration charts: (a) measured enthalpy
versus hydration index and (b) theoretical free energy versus hydration
index for various clays (after A. Hayatdavoudi, ©1999 SPE; reprinted by per-
mission of the Society of Petroleum Engineers).