Page 249 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

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Gas
Production well Emulsions
biocides Oil Injection well
F Primary
separation G Water Produced water Sea water
Well head reinjection Injection
Environment Water
limits quality

E A

B
D C
Figure 5.2 Offshore production and injection system with possible scaling locations.
(A) Injection wellbore, (B) near injection wellbore region, (C) formation, (D) near pro-
duction wellbore region, (E) production wellbore, (F) wellhead, and (G) separator.

and within the wellhead and Christmas trees. If scaling occurs along the
wellbore, it will have a significant impact on well performance, integrity,
and operability, and may eventually even lead to the cessation of produc-
tion. Cases such as perforation scale off, gravel pack or screen blockages,
tubing blockage, safety valve, or choke failure have been reported in liter-
ature due to inorganic deposition in reservoir and near wellbore location.
Options for scaling prevention and mitigation are available in practice.
Chemical methods such as injecting scaling inhibitors and mechanical
methods can be used if necessary. However, the operator should focus on
preventing scaling deposition rather than remediation efforts, which are
usually more time consuming and costly. Remediation and mitigation
actions should be used as the last resort to overcome scale issues.

5.2 TYPES OF SCALES IN FORMATION DAMAGE

Many types of solid particles can precipitate when brine conditions
change. Here, we classify them into three categories: Carbonate scales,
Sulfates scales, and others.