Concept selection and initial design of deepwater subsea production systems can have a profound
impact on the evaluation of the commercial viability of a discovery. Although detailed design comes
later in the process, the decisions made at this early stage of a project will generally provide the
template that is carried through to construction and operation. Scale management can be a significant
factor in deciding the outcome of the concept selection phase, particularly for fields that are expected to
require seawater injection at some stage in their design life. Early in a project it is common to have
information from only one or two exploration wells and where water samples are often not available, are
heavily contaminated, or have been gathered from locations away from the main production targets.
This paper outlines the difficulties faced when evaluating the various scale management techniques
available to deepwater operators at the early stages of the project design process and in providing fit
for purpose design recommendations that are not overly conservative but that still account for the risk
posed by having only limited supporting information available. An approach is presented that addresses
these risks and uncertainties by applying scale modeling along with a simple heuristic strategy to
support the selection of appropriate scale management techniques for deepwater subsea fields.
Several comparative examples for projects in the Gulf of Mexico are provided to explain the different
outcomes that can result from this process.
Key words: Deepwater, Risk Management, Scale, Subsea, Water Injection