Blocks 3&4

Tethys Oil acquired interest in the licence for Blocks 3&4 in 2007. The blocks cover an area of 29,130 km2 in the central eastern part of Oman. Tethys Oil, through its wholly owned subsidiary Tethys Oil Block 3 & 4 Ltd, has a 30 percent interest in Blocks 3&4. Partners are Mitsui E&P Middle East B.V. with 20 percent and the operator CC Energy Development S.A.L. (Oman branch) holding the remaining 50 percent.

In 2012, the Field Development Plan for Blocks 3&4 was approved and the exploration and production terms for the licence were extended until 2040. Production has been launched in three areas on the blocks: Farha South, Saiwan East and Shahd production areas. Since an early production system was launched in August 2010, Tethys Oil’s share of the production (before government take) has increased from some 200 bopd per day to around 12,000 bopd in 2017. In 2017, three new discoveries were made: Erfan, Ulfa and Samah.

Farha South production area
The main producing layer at the Farha South area is the Barik sandstone at depth of about 1,600 metres. The oil of the Farha South is not trapped in one large continuous reservoir. It is instead trapped in a large number of smaller, usually adjacent fault blocks. These faults are relatively small and 3D seismic has been essential in the mapping of drillable fault blocks. The low content of gas combined with the absence of a water drive in the Barik layer make pumps and water injection necessary. Water is injected into the reservoir via injection wells in order to increase the pressure and thereby stimulate production. The oil from the Barik layer is of high quality, more than 40 degrees API and does not contain any sulphur.

Shahd production area
At the Shahd area, oil is extracted mainly from the Lower Buah carbonate at 2,000 metres but also from the Khufai carbonate and the Lower al Bashir sandstone. The oil from the Lower Buah layer holds a quality of approximately 38 degrees API. Like the Farha South field, this area is also highly faulted and the Lower Buah layer in the field is not one large continuous reservoir. The oil is instead trapped in separate structures.

Saiwan East production area
At the Saiwan East, the oil is produced from the Khufai carbonate at depths ranging from 1,700 to 2,400 metres. This reservoir was previously unknown as an oil producer in Oman. The oil from the Khufai layer holds a quality of approximately 32 degrees API.

New areas
In 2017, four exploration wells were drilled which resulted in the three new discoveries Erfan, Ulfa and Samah. These three discoveries have added more than 17 mmbo of 2C contingent resources and the majority of some five mmbo of 2P reserves added in 2017. Development of the Contingent Resources in the new discoveries will be contingent on the ongoing appraisal programme and also a work programme and budget to access these resources.

About Tethys Oil

Tethys Oil is a Swedish oil company with focus on onshore areas with known oil discoveries. The company’s core area is the Sultanate of Oman, where it holds interests in Blocks 3&4, Block 49, Block 56 and Block 58. Tethys Oil has net working interest 2P reserves of 26.1 mmbo and net working interest 2C Contingent Resources of 13.5 mmbo and had an average oil production of 12,832 barrels per day from Blocks 3&4 during 2019. The company’s shares are listed on Nasdaq Stockholm (TETY). Website: