Page 26 - Reservoir Formation Damage

Chapter 2

Mineralogy and
Mineral Sensitivity

of Petroleum-Bearing
Formations*

Summary

The origin, mineralogy, and mineral sensitivity of petroleum-bearing for-
mations are reviewed. The mechanisms of mineral swelling, alteration, and
fines generation are described. The models for mineral sensitive properties
of rock and the methods for interpretation of experimental data are presented.

Introduction
Among others, Ohen and Civan (1993) point out that fines migration
and clay swelling are the primary reasons for formation damage measured
as permeability impairment. Poorly lithified and tightly packed formations
having large quantities of authigenic, pore filling clays sensitive to aque-
ous solutions, such as kaolinite, illite, smectite, chlorite, and mixed-layer
clay minerals, are especially susceptible to formation damage (Amaefule
et al., 1988). Formation damage also occurs as a result of the invasion
of drilling mud, cements, and other debris during production, hydraulic
fracturing, and workover operations (Amaefule et al., 1988).
This chapter describes the mineral content and sensitivity of typical sedi-
mentary formations, and the relevant formation damage mechanisms involv-
ing clay alteration and migration. Analytical models for interpretation and
correlation of the effects of clay swelling on the permeability and porosity
of clayey porous rocks are presented (Civan, 1999). The parameters of the

* Parts of this chapter have been reprinted with permission of the Society of Petroleum
Engineers from Civan (1999).

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