Petroleum Development Oman (PDO) has struck oil again in one of the Sultanate’s most productive geological formations, giving a boost to the company’s exploration effort. According to ONA, the oil was discovered in the Shuaiba Formation, which lies in northwest Oman, in the Malaan area.
The Shuaiba Formation has been yielding oil for Oman for quite some time. It contains, for example, the reservoirs of the Yibal Field, which is now into its fourth decade of production. The Malaan location was first targeted in the year 2000 as a likely place to find more oil reserves in the formation. Yet the first well drilled three – Malaan1- proved a disappointment when it failed to produce oil at economic flow rates. However, perseverance and further studies of the seismic and well data uncovered an ancient shoreline stretching along the edge of the Malaan structure.
Stephen Hiebert, Senior Interpreter at PDO said “The analysis of the seismic and well date led to a revised interpretation of the geological setting, indicating a stratigraphic trap,”. A stratigraphic is a geological formation containing hydrocarbons within permeable rocks that have been sealed by impermeable sedimentary rocks deposited around it. Unlike the more common structural traps, stratigraphic traps are not characterised by folding or faulting, which can be readily detected on seismic images. In the case of the Malaan structure the stratigraphic trap was created by sedimentation around shoal rocks formed by ancient marine organisms, such as coral. As Mr lliebert further explains: “The new setting suggested that we could expect better-quality reservoirs and a higher oil content down the flank of the Malaan structure. But this theory is counter to the conventional thinking of petroleum prospectors, which holds that the most likely place for good oil production is at the crest of a geological structure.” (menareport.com)
© 2004 Mena Report (www.menareport.com)
