corrosive species and scaling in wells at olkaria ... - Orkustofnun

Peeled off part on coupon
# 17 at retention tank
Well
NJ-14
Retention
tank
After heat
exchangers
Re-injection
well
Well
NJ-22
FIGURE 32: Photograph of coupons after a 13 week test period
A
B
Weight gain after 29
weeks. Coupon # 18
Weight gain after 29
weeks. Coupon # 19
FIGURE 33: Photos showing deposition of scale on test coupons at, a) The retention tank;
and b) The injection well
Of coupons removed from the retention tank and heat exchangers after 13 weeks, there was some scale
on one coupon that peeled off slightly while it was being removed so that the measured weight gain is
low for this coupon. The coupons after 13 weeks in the test environment are shown in Figure 32. In
Figures 33 there are shown photographs of test coupons at the entry to the retention tank and at the
injection well, respectively.
7.3.1 Binocular microscope descriptions
Coupon # 16 (After heat exchangers): Fine grained dark grayish deposits observed on the coupon. The
deposit formed thin sheets that indicated signs of peeling off. Dark grey deposits on the edges. There
appeared to flow banding on the edges.
34