Kazakh Exploration Well Flows Commercial Oil

April 18, 2011

BOZOI, KAZAKHSTAN, Apr 18, 2011 (MARKETWIRE via COMTEX) —

Tethys Petroleum Limited (“Tethys” or the “Company” (TSX: TPL) today provided an operational update on its activities in Kazakhstan.

HIGHLIGHTS

-- Exploration well AKD03 well tests commercial oil in secondary target -- Sandstone unit in Upper Jurassic opens up a new play within the Greater Doris area -- Doris appraisal wells AKD04 and AKD05 progressing as planned with AKD04 expected to reach total depth by early May 2011 and AKD05 by the end of May 2011. These are the first wells to be drilled based on the new 3D seismic dataset -- Kul-Bas exploration well KBD01 to reach total depth in June/July 2011

The AKD03 (“Dione”) exploration well, which is located approximately 10 km to the south-west of the AKD01 Doris discovery well (on a separate prospect), reached its total depth of 3,975 metres in January 2011. A comprehensive testing program commenced in March 2011 upon approval by the Kazakh State. Recent testing of a sandstone unit within the Upper Jurassic of AKD03 flowed at rates of over 400 barrels of oil per day (“bopd”) of 43 degree API oil over the interval 2,506-2,520 metres on a 12mm choke with no water being produced on test and no depletion observed. This interval was not included in the recent reserves report produced by McDaniel and has opened up a new play within the Greater Doris area that will form an additional target in current and future exploration and appraisal wells, including AKD04 and AKD05.

The well is now being prepared to test the Upper Jurassic carbonate interval that flowed on the original AKD01 Doris Discovery well, with results expected in early May 2011. This test will be followed by the testing of the good quality potentially oil bearing Cretaceous sandstone interval (which is similar to the main reservoir zone in the AKD01 well) and which shows the best reservoir properties of the zones being tested.

The AKD04 (“Dero”) well is located to the east of the Doris crest in order to test the continuation of the structure there. The well is currently at a depth of 1,665 metres and is drilling ahead with a planned total depth of approximately 2,550 metres expected to be reached by early May at which time a full suite of electric logs will be run and casing set, prior to testing.

The AKD05 Doris appraisal well is being drilled immediately up-dip of the AKD01 well and will be targeting both the Lower Cretaceous (Aptian) sandstones and Jurassic carbonates that were successfully tested in AKD01, as well as a possible third, overlying, horizon in the Middle Cretaceous (Albian) sandstone horizon. The well is at a current depth of 568 metres and is drilling ahead. Drilling will continue to a planned total depth of 2,500 metres, which should be reached in the latter part of May.

The KBD01 (“Kalypso”) exploration well is located approximately 50 km to the north-west of the Doris oil discovery. The well is drilling ahead after recently setting casing at a depth of 1,398 metres. The planned total depth of this well is approximately 4,000 metres, which is expected to be reached at the end of June / early July.

This well targets potential reservoirs at several stratigraphic levels from the Cretaceous to the Permo-Carboniferous. The KBD01 well is the first deep exploration well to be drilled by the Company on the Kul-Bas Block, which also contains several other attractive prospects.

The Upper Jurassic carbonate intervals in both the AKD02 (“Doris NW”) appraisal well and the G6RE (“Dodone”) exploration well await testing with the application of radial drilling technology which is forecast to be in June 2011 when the equipment arrives on site. Further testing of these wells will be dependent on the results of the radial drilling.

An application has now been made to the Kazakh government for the next well to be drilled after AKD04, which is planned to be located on the Doto prospect south-west of Doris.

Drilling and testing operations have been delayed somewhat by prolonged Spring breakout and extremely muddy and poor road conditions. These conditions have particularly affected the disposal of drill cuttings that until last week were being transported a significant distance to a disposal site in order to conform to Kazakh environmental regulations. Now with the recent completion of a third party environmental disposal facility for drill cuttings located much closer to the drill sites, the efficiency of the disposal process has greatly improved and also therefore the efficiency of the drilling operations. The facility is now operational and weather conditions have also significantly improved.

Despite the recent poor road conditions, work is proceeding well on the Doris Pilot Oil Production Project, aimed at significantly increasing oil production from the field with the initial target to be producing some 3,000 bopd by the end of June 2011.

In addition Tethys has now been informed by the Ministry of Oil and Gas of the Republic of Kazakhstan (“MOG”) that it has included Tethys’ Kazakh subsidiaries, TethysAralGaz LLP and Kul-Bas LLP, on its list of subsoil users which comply with the recent new rules on Kazakh content. Tethys has worked hard with the appropriate Kazakh authorities to ensure compliance with these rules and is very pleased to be one of the few subsoil users who currently comply.

Tethys is focused on oil and gas exploration and production activities in Central Asia with activities currently in the Republics of Tajikistan, Kazakhstan and Uzbekistan. This highly prolific oil and gas area is rapidly developing and Tethys believes that significant potential exists in both exploration and in discovered deposits.

This press release contains “forward-looking information” which may include, but is not limited to, statements with respect to our operations. Such forward looking statements reflect our current views with respect to future events and are subject to certain risks, uncertainties and assumptions. See our Annual Information Form for the year ended December 31, 2010 for a description of risks and uncertainties relevant to our business, including our exploration and development activities. Test production rates may vary from sustained production rates when developing a well or a deposit. The commerciality of any discovery can be affected by many factors including product prices, operating costs, capital costs, government take and sustained production levels and ultimate recovery of hydrocarbons.

Contacts: Tethys Petroleum Limited Sabin Rossi Vice President Investor Relations +1 416 572 2065 +1 416 572 2201 (FAX) info@tethyspetroleum.com www.tethyspetroleum.com Tethys Petroleum Limited TD Canada Trust Tower 161 Bay Street, 27th Floor Toronto N5J 2S1, Canada Mobile site: http://m.tethyspetroleum.com In Asia-Pacific: Quam IR Anita Wan Associate Director + (852) 2217-2999 + (852) 2217-2999 (FAX) anita.wan@quamgroup.com
SOURCE: Tethys Petroleum Limited

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