I an not sure what you are looking for exactly. Note that $\sup$ and $\inf$ are included as operators in the language so any Skolemization would need to have them.
BenyacovBenYaacov et al. give some quantifier elimination results for continuous logic theories in the following paper:
- BenYaacov, Berenstein, Henson, and Usvyatsov, "Model theory for metric structures", 2008.
Here is an alternative view that I personally find easier to work with and might be helpful:
theories in continuous logic can be thought of as theories in first-order rational Pavelka logic $RPL\forall$, which is in turn a conservative extension of classical first-order logic.
We use this to construct Henkin models for CL in the following paper:
- Didehvar, Ghasemloo, and Pourmahdian, "Effectiveness in RPL, with Applications to Continuous Logic", 2010
The reference to learn more about $RPL\forall$ is
- Hajek, "Metamathematics of Fuzzy Logic", 1989.
You may want to also check:
- Chang and Keisler, "Continuous Model Theory", 1966.
- Metcalfe, Olivetti, and Gabbay, "Proof Theory for Fuzzy Logics", 2009.