The Orassin distortion field was an area of very dense spatial anomalies generated by the first sphere encountered by the Enterprise NX-01 in the Delphic Expanse.

The field was used as a hunting ground by Osaarian pirates, who would attack and raid any ship which was disabled by the anomalies. They attacked Enterprise in this manner, stealing a number of resources and supplies from the Starfleet vessel. (ENT: "The Xindi", "Anomaly")