Reproducibility has long been a cornerstone of science. Underpinning reproducibility is provenance, which has the potential to provide scientists with a complete understanding of data generated in e-experiments, including the services that were produced and consumed. This paper explores the issues of service versioning in provenance to achieve reproducibility. Current provenance model does not directly support service versioning. Therefore, this paper introduces an enhancement of a provenance model to incorporate service versioning mechanism that provides a way to access multiple versions of the same service so that researcher can compare one version to another, and understand their effects on processing data. The enhanced provenance model is able to track the changes of the same service (versions of the same service) over time and correlates versioned services with the results they generate.