oa Biosteering in Margham Field, Onshore Dubai - A Case Study on Significant Updating of the Static Model During a UBCTD Campaign

Following successful introduction to the Middle East of underbalanced, coil tubing drilling, with biosteering (use of microfossils from cuttings samples to identify individual layers within the reservoir succession by reference to field-specific zonation schemes) as the geosteering method of choice, a campaign was planned for 2006 in the Margham Field, onshore Dubai. The field, discovered in 1982, had been developed by means of conventional drilling of 17 vertical and 2 deviated wells into Lower Cretaceous carbonate reservoirs over a period of more than 20 years. From the outset, it had been understood that the field was tectonically and structurally complex, forming part of the arc of thrustaffected structures that occur to the west of the Oman Mountains. Conventional biostratigraphy had assisted in early interpretation of major faulting in the Tertiary and Upper Cretaceous sections above the reservoirs, but seismic resolution was unable to clarify any degree of faulting within the Lower Cretaceous.