THE DEVELOPMENT OF A FRACTURED RESERVOIR MODEL FOR THE PALM VALLEY GAS FIELD

Abstract

A fractured reservoir model has been developed for the Palm Valley gas field, located WSW of Alice Springs, in the Amadeus Basin, NT. Definition of this complex, naturally fractured, Ordovician gas reservoir has required an integrated approach involving multiple studies to develop the geological model that has formed the basis for reservoir simulation and the rationale for the location of new wells. In addition, new seismic data provided fundamental input to the structure/fracture model of the field. Results suggest a primary, northsouth compression for the origin of structures in the basin and that Palm Valley resulted from a single, balanced folding phase. The seismic data show that Palm Valley is not an arcuate anticline as previously mapped, but is an elongate WSW to ENE trending, doubly plunging anticline with an offset crest and minor reverse faults at reservoir level. Investigations have shown that the majority of fractures in the reservoir outcrop are extremely ordered and there is definite structural control of the fracture spacing in the brittle reservoir rocks. Fracture trajectory and fracture intensity maps have been constructed, the latter providing the mechanism for distribution of fracture parameters around the field. The orientation of fractures measured at depth in the reservoir match exactly the fractures predicted from the structure/fracture model. This is the first time a fractured reservoir model that has been developed for Palm Valley, and it will form the basis for the further study and future development of the field.