Discovery of new petroleum district on north-western slope of Aldansky syneclise (Siberian platform)

The paper presents the results of seismic surveys and wildcat drilling in the Biryuksky and Mukhtinsky license areas. The works were conducted within the framework of the Vostochny (Eastern) Gas Program and had the purposes of searching for oil and gas pools, updating petroleum potential of the Cambrian, Vendian, and Riphean deposits. Seismic exploration has for the first time identified a promising oil and gas accumulation zone situated along the tectonic boundary of the Berezovsky depression and the north-western slope of the Aldansky anteclise, which is represented by a group of anticlinal structures. Wildcat drilling on two prepared local structures (Ust’-Biryuksky in the south and Mukhtinsky in the north of the mentioned zone) has confirmed the commercial gas bearing capacity of the zone. In the Biryukskaya-646-2ПБ well drilled on the Ust’-Biryuksky structure, gas influx was obtained from the Vendian-Cambrian deposits of the Osinsky and Yuryuakhsky horizons. Drilling data of the Mukhtinskaya-647-1ПМ well confirmed productivity of horizons of the Charsky Formation. The new Petroleum District was discovered. The results of prospecting and appraisal works support the concept of high potential and chances of commercial gas pool discovery in the Riphean deposits (Alekseevsky, Chekurdakhsky formations). In the Vendian deposits, Telgespitsky horizon is still considered promising, and high content of gas dissolved in formation water obtained in testing is an indirect evidence of this fact. Structural and tectonic as well as lithological indicators are key drivers for the accumulation occurrence. Presence of the closed stratigraphic (anticline) trap is an exploration lead