The drilling programme onshore the Sultane of Oman has continued with the testing of the Saiwan East -4 well (SE-4) on Block 4. SE-4 was drilled in the summer of 2010, but was not tested at the time. Results from the testing suggest that the oil in this part of Block 4 is of a different quality from the oil encountered in previous Saiwan wells. The data also suggests that considerably larger parts than previously believed of the more than 400 metres thick Khufai section could contain oil of various qualities. The oil encountered in SE-4 could range in density from the 33 degree API oil produced from SE-2 and SE-3 to the heavy oil encountered above the Khufai in these wells.

In the previous Saiwan wells, SE-2 and SE-3, oil was only confirmed in the upper parts of the Khufai section. The extensive log and core data obtained from SE-4 last summer has now been expanded by data from six production tests spanning more than 400 metres of separate intervals principally in the Khufai limestone. No flows were established and some hole conditions resulted in encountering water bearing fractures in the top part of the Khufai interfering with test data from this zone. The actual production capability of SE-4 therefore remains undetermined.

The SE-4 results will however prompt a reevaluation of the data obtained from SE-2 and SE-3 as regards the potential for oil also in the lower parts of these wells. Further analysis will also be done in SE-4 and the well will remain suspended to allow for additional production tests at a later date.

Immediate focus will now be on drilling the next Saiwan well, designated SE-6 which is being drilled 2.4 kilometres north of SE 3 to appraise the northern part of the Saiwan area.

"The Saiwan are continues to surprise us. Last summer we encountered way better flow rates than expected in SE-3 when this well flowed more than 10,000 BOPD of 33 degree oil from the upper parts of the Khufai. In SE-4 we seem to have encountered unexpectedly large quantities of oil with different gravities and viscosities than previously believed possible. We will have to wait and see what impact this will have on the resource calculation, but indications are that yet a new play concept may have opened up. The results underscore the complexity, but also the potential, of Block 4 in general and the Saiwan area in particular," says Magnus Nordin, Managing Director of Tethys Oil AB.

Tethys has a 30 per cent interest in Blocks 3 and 4. Partners are Mitsui E&P Middle East B.V. with 20 per cent and the operator CC Energy Development S.A.L. (Oman branch) holding the remaining 50 per cent.

Tags: Tethys Oil