PREDICT is a new generation software tool that addresses one of the most significant in corrosion evaluation, i.e., assessment of corrosion rates in steels exposed to corrosive environments. PREDICT, a by-product of years of corrosion research and modeling, puts to good use application of state-of-the-art software technology to provide access to a comprehensive knowledge on corrosion decision-making.

It's easy-to-use graphical tool integrates the effects of a complex set of environmental parameters to provide a corrosion rate assessment based on extensive literature data, lab testing and field experience. Figure 2 shows a flow chart detailing how Predict estimates corrosion rates.

Characteristics

• PREDICT performs a rigorous evaluation of corrosive environments and provides assessment of corrosion rates.
• Incorporates comprehensive and accurate corrosion modeling to account for the effects of a number of critical parameters
• Helps in the determination of system pH for typical oil and gas environments
• Provides decision-making rules for corrosion characterization on the basis of a corrosion model that accounts for the interaction of different critical parameters.
• Determines annualized and present worth cost as a means to conducting cost analyses to compare different material choices.
• Includes an intuitive, graphical, easy-to-use interface.

Benefits

• Microsoft® Windows based tool that can run on most common personal computers
• Easy to use graphical interface makes using the system a simple task.
• Extensive on-line help assists the user in understanding the significance different corrosion evaluation parameters
• Cost analysis module facilitates comparison of project cost when using different materials
• Can be easily installed on any stand-alone or network system compatible with Windows/Windows NT/Windows for Work groups/Windows-95, 98 operating system
• Can lead to significant reduction in time spent assessing corrosion and can be a means for obtaining cost-effective automated solutions
• Access to extensive consulting and development support from InterCorr in using/customizing PREDICT
• Network and Y2K Compliant.

Consulting Predict

Consulting PREDICT is designed to be an intuitively simple task. The user can specify data for any of the parameters and watch the effect of that parameter on the corrosion rate in the system. The system starts with a set of default values and calculates a corrosion rate based on any changes to the displayed values on an as-you-see-it basis. While PREDICT uses a complex computational model for determining the corrosion rate, the ease-of-use in applying the system to obtain meaningful answers is apparent. However, the answers displayed obviously reflect data input by the user. Figure 2 shows a flow chart that depicts the reasoning in Predict.

In the following paragraphs, we will go through a typical consultation in a step-by-step manner:

1. Specification of pH related data: At the outset, PREDICT determines a corrosion rate only if you have an acidic environment. So, if your environment has no acid gases or there is sufficient buffering (read "bicarbonates") to produce a pH higher than 7.0, the system will PREDICT zero or very low corrosion rates. So, the first step in consulting PREDICT involves specification of the acid gas (H₂S and CO₂) partial pressures as well as the bicarbonate content of the environment. If you do not have partial pressures available and instead have a ppm or a percent, use the on-line help in PREDICT. It tells you how to convert between different unit systems or methods of measuring presence of a certain element in an environment.

2. Temperature/Gas-Water ratios: Temperature has a strong effect on corrosion rates. Corrosion rates significantly increase with increasing maximum temperature. The minimum temperature in PREDICT has only one role. It is to determine whether there is any condensed water in the system for gas wells. If the Gas to Oil Ratio is more than 5000 scf/bbl (which denotes a gas well), the system uses the water to gas ratio and the dew point as means to determine availability of an aqueous medium to measure corrosion. So, depending on the value entered for the Gas to Oil Ratio, the system will let you specify the relevant water-related parameters. If the Gas to Oil Ratio is less than 5000 scf/bbl (which denotes an oil well), the system uses the water cut and oil persistency to determine the wetness effect (in which case the minimum temperature has no role).

3. Chlorides/aeration/sulfur: These parameters typically make corrosion worse if the process has been initiated by the presence of acid gases. Their role, while not as critical as that of H₂S or CO₂, is significant because these parameters can significantly increase corrosion rates in mildly corrosive systems.

4. Velocity/Type of flow: Flow parameters are very critical in both determining and controlling corrosion effects. Erosion corrosion as well as the protection (or the lack of it) from corrosion films is very much a function of fluid velocity.

5. Inhibition/corrosion allowance: Inhibition choices in PREDICT allow the user to select applicable methods of inhibition for vertical or horizontal flow and determine the extent of corrosion mitigation. In some cases, the system might provide no protection due to inhibition because of high velocities or chloride concentrations. PREDICT has in-built rules to assess the appropriate method of inhibition for a given set of conditions and can also determine whether a specified method of inhibition is applicable or not to the specified conditions.