Ghost Ranch Field, Nevada: New Discovery from Combined 3-D Seismic and Well Log Data

Ghost Ranch field was discovered in 1996 on the basis of a 3-D (three-dimensional) seismic survey guided by analysis of log data from nearby existing wells. The 7 mi² (18 km²) survey had the initial goal of identifying infill opportunities in Eagle Springs field and led to the drilling of a series of new producers. Results from this activity, combined with log data from nearby Kate Spring field, enabled the mapping of an oil-bearing Paleozoic slide-block mass between the two fields. A structural high with four-way closure, roughly 40–50 ac (16–20 ha) in size, was identified and successfully drilled to open Ghost Ranch field. Ghost Ranch produces from fractured Devonian dolomites at depths of about 4350–4400 ft (1326–1342 m). The field has a strong water drive, an oil column of 100 ft (30 m), and estimated original oil in place (OOIP) of 2 million bbl. Production through January 1999 was 216.7 mbbl (11% OOIP) from three wells. Success at Ghost Ranch suggests that the updip margins of the productive slide-block mass define an excellent target for future exploration.