The largest gas field in the Pattani Basin is Erawan, operated by Unocal. This field is a large structure in a basin-center location. The structure is antiformal but pervasively faulted. A story about this field illustrates the structural and stratigraphic complexity of this basin. After the field had been discovered and delineated, the first development well was a dry hole. A major 3-D seismic effort followed (one of the first in the world) and resulted in a very successful development.