ABSTRACT :
The injected fluid may not be compatible with the native pore fluid during treatment of reservoirs or
waterflooding. This incompatibility results in chemical none equilibrium in the porous system. Ions in the
source water may react with ions in the reservoir fluids to form solid precipitates downstream in the
porous system to plug pore throats or to deposit onto pore walls resulting in porosity reduction.
Precipitation of mineral scales causes many problems in oil and gas production operations such as
formation damage, production losses, increased workovers in producers and injectors, poor injection
water quality, and equipment failures due to under-deposit corrosion. The most common mineral scales
are sulphate and carbonate-based minerals. However, scale problems are not limited to these minerals
and there have recently been reports of unusual scale types such as zinc and lead sulfides (Collins and
Jordan, 2003).