Tethys Encouraged by Akkulka Well's Flow Rate in Kazakhstan
Tethys Petroleum announced that the lower zone of the AKD01 Exploration well in Kazakhstan has flowed at over 2,800 barrels per day ("bpd"), with 1,373 barrels of oil per day ("bopd") after acidization.
Graham Wall, Vice President Technical of Tethys commented, "We are extremely pleased by the success of the acidization on this well. The well is flowing strongly with increasing pressures and flow as it continues to clean up following the acidisation. A temporary suspension of testing is necessary for us to prepare storage for the volumes of fluid being produced and also to evaluate the test data gathered to date. This is, we believe, the first test of oil in this part of Kazakhstan and opens up an area of substantial potential in our Akkulka and Kul-Bas blocks. Reservoir quality in this zone appears good as does the quality of the produced oil which bodes well for the ultimate development of this reservoir. It is still too early to assess the full potential of this exploration oil discovery but the initial results are very encouraging."
Well AKD01 encountered two zones of potential moveable hydrocarbons, a lower zone interpreted as being a Jurassic dolomite sequence and an upper zone interpreted as a Cretaceous sandstone. The initial testing of the lower zone yielded light oil to surface but analysis of the test data indicated a reduction in permeability immediately proximal to the wellbore and which should be improved by acidisation. The international oil service company Schlumberger carried out the acidization with the CleanSWEEP solvent system, which data indicated proceeded successfully. Treatment was conducted with Schlumberger surface equipment and through its downhole packer system.
Following the acidization, testing of the well continued and the well has now been flowed at rates of up to 2,803 bpd on a 24 mm (60/64") choke with a flowing tubing head pressure of 14.2 atmospheres (209 psig) and with the well still cleaning up. Currently approximately 50% of the flow is a 45 degree API crude oil, the remainder being hyper-saline brine and spent acid. It is possible that this fluid may be a mixture of completion fluid and formation brine, coming from a zone below the oil bearing dolomite although this is not currently clear and production logs are to be run to help clarify the situation. Pressure build ups suggest that the reservoir has a good productivity index (PI). The oil bearing dolomite zone is interpreted to have 8.2 metres (27 feet) of net pay with a porosity of 16.9% and appears to be regionally extensive. Current mapping indicates that the AKD01 well is in a downdip location on the prospect (named "Doris") with approximately 56 meters (184 feet) of elevation updip of the well and covering a most likely area of some 60 km2 (14,826 acres).
The well is being tested in sub-zero conditions in a remote desert location distant from existing infrastructure and with limited storage capacity for oil and with time required to install further capacity and move the oil which is currently stored on site. As such it is planned to suspend testing of the well until the oil has been shipped and additional tankage installed, this expected to take until early January 2010.
The upper sandstone interval which is interpreted to have approximately 9 metres (29 feet) of net pay with a porosity of 23% and a hydrocarbon saturation of 76% has not yet been tested.
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Company: Tethys Petroleum Limited more info
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