Page 366 - Reservoir Formation Damage

346 Reservoir Formation Damage

Water Analyses

Although the analyses of the various Jo Mill Unit produced waters
were available from the Inorganic Laboratory of Texaco EPTD, Schneider
(1997) considered only the analyses of waters from the wells at five
locations that did not make any appreciable amount of water. Therefore,
for all practical purposes, these locations preserved their original water
compositions. He also considered the analyses of the Mule Shoe Ranch
and Canyon Reef waters that can be used for drilling and waterflooding
operations. The analyses of these waters are presented in Table 13-1 by
Schneider (1997).
Schneider (1997) used the SOLMINEQ.88 software to simulate the
potential interactions and adverse affects of the formation minerals and
aqueous phase. He assumed equilibrium conditions for conservative
predictions of the rock-fluid interactions and water compatibility.

Saturation Index Charts

The compatibility of foreign water with the JMU reservoir connate
water is investigated in this section using the saturation index charts.
Saturation Indices of the JMU Reservoir Waters

Schneider (1997) determined the saturation indices of the carbonates
and sulfates, given in Table 13-2 for the JMU #7231 water using the
SOLMINEQ.88 program. The saturation index values reported with
positive and negative signs in Table 13-2 indicate conditions of super-
saturation and under-saturation, respectively, for various minerals. The
only unexpected result is the unusually low predicted siderite under-
saturation of the water. However, in general, the saturation indices of the
various minerals calculated by the SOLMINEQ.88 program is consistent
with the mineralogy of the JMU sandstone formation. This is a further
confirmation of the accuracy of the geochemical model (Schneider, 1997).

Mixing Paths on the Mineral Stability Charts

Effects of mixing foreign and reservoir waters on mineral stability are
best realized by constructing mixing paths on the mineral stability charts.
Schneider (1997) investigated the compatibility of the JMU #7231 well
connate water with the Mule Shoe Ranch and Canyon Reef waters
considered for potential use in drilling and/or water flooding operations.
The analyses of these waters are given by Schneider (1997) in Table
13-1. It is apparent that the Mule Shoe water has a higher CO^ 1 and