| A strong and stable flow of gas with condensate content, together with the current geophysical data, indicate a field discovery in the Shyrak-1 exploration well. |
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| Own release | |
| 23.08.2011 | |
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The Management Board of PETROLINVEST S.A. (the “Company”) announces that on 23 August 2011 the Company was informed by TOO OilTechnoGroup, a Kazakh law company controlled by the Company (“OTG”), that OTG is effectively terminating works aimed at restoring the pressure balance and stabilizing the Shyrak 1 exploration well after a strong and continuous flow of natural gas with condensate content. The flow occurred at a depth of 6,597.1 meters, i.e. at the final depth of the well, of which the Company informed in current report no. 77/2011 dated 16 August 2011. At the time of gas flow the well was filled with drilling mud of a specific weight of 1.77 g/cm3. When the flow was discovered, the blowout preventer was closed, and then, for the time necessary to prepare heavier drilling mud, mud circulation were performed aimed at washing out as much natural gas and condensate as possible. During the mud circulation, gas inflowing into the well caused a decrease of drilling mud weight up to over 0.50 g/cm3. The amount of gas was so high that it had to be separated and combusted on the flare. On 21 August 2011, heavier drilling mud of 1.9 g/cm3 was inlaid to the well at a volume equal to the full capacity of the well, thus removing the drilling mud saturated with natural gas and condensate. After completing a full cycle of mud circulation, the pumping was stopped periodically and the blowout preventer was closed to enable the pressure check, which demonstrated a pressure of 104.3 atmospheres. On this basis, the formation pressure at the bottom of the well was estimated at about 1,360 atmospheres, and the required equivalent mud weight should be at least 2.05 g/cm3. The detected gas flow was exceptionally strong. Apart from gas, the drilling mud also contains traces of liquid hydrocarbons. Earlier, the Company informed the public that analyses showed the presence of heavy gases in the natural gas composition (n-butane, iso-butane and pentane), which are components of the condensate. Also, the nature of natural gas combustion indicates the presence of a large admixture of condensate or crude oil, and the results of additional physicochemical analyses are required to confirm the presence of the latter. Results of drilling, shows observed in the process of drilling, especially those occurring now, and the results of the interpretation of logs indicate the discovery of a field. Well rate and size of the reserves will be determined based on the results of testing. Pressure (104.3 atmospheres) recorded on the blowout preventer with the drilling mud weighing 1.9 g/cm3 and 6,597.1 meters deep gas inflow, confirms very high formation pressure. Currently, the Company and OTG carry out analyses and discussions on how to effectively examine the drilled lower part of condensate gas field while maintaining all safety requirements regarding the well. |