Page 134 - Fundamentals of Enhanced Oil and Gas Recovery

122 Pouria Behnoudfar et al.

of different reservoir parameters on CO 2 EOR efficiency by carrying a comprehensive
simulation out. They achieved a set of optimum values for reservoir and oil properties,
which are best suited for CO 2 EOR operation. Based on this table, weighting factors
indicate the relative importance of each parameter.

4.8 CORROSION
4.8.1 Facility and Corrosion

One of the main challenges to oil industry has always been CO 2 -related problems on
facilities. In addition, its great impact on economic aspects of projects is remarkable.
For instance, CO 2 may cause severe corrosion on pipelines, well tubing, and pumping
equipment [86]. Effect of CO 2 injection on the reservoir formation and reservoir fluid
should also be taken into account. One example of these impacts is solid deposition
caused by CO 2 mixing with reservoir fluids, such as scale formation and asphaltene
precipitation. For offshore projects, possible problems are related to platforms, well
completion, and pipelines to handle CO 2 , such as extra weight on injection and pro-
duction platforms, and hydrate formation [87].
By increasing CO 2 injection operations and also the fact that its stages are taken
place in different locations, numerous technological and engineering advances made
over the past 35 years in CO 2 injection were well designed, including [88,89]:
• Corrosion-resistant materials such as stainless and alloy steels [316 SS, nickel, Monel,
corrosion resistant alloy (CRA), etc.] for piping and metal component trim,
• Swell-resistant elastomer materials such as Buna-N and Nitrile rubbers for down-
hole packers, and Teflon or Polytetrafluoroethylene (PTFE) and Nylon for seals,
• Fiberglass lined (GRE) and internally plastic coated (IPC) pipe (phenolics, epoxies,
urethanes, and novolacs) tubing strings to retard corrosion,
• Acid-resistant cements containing latex, pozzolan, alumina, and other additives,
• Automatic control systems that not only regulate flows but also provide real-time
monitoring which is capable of initiating well shutdowns in an unsafe condition.
Various innovations in tools and hardware are also manufactured which have had
an important role in development of operational and safety practices, including [88]:
• Use of corrosion protection of the casing strings via impressed and passive currents
and chemically inhibited fluid (oxygen, biocide, corrosion inhibitor) in the
casing tubing annulus,
• Use of special procedures for handling and installing the production tubing to pro-
vide gas tight seals between adjacent tubing joints and to avoid coating damage or
liner damage,