MUTULA HIGH AS A PRINCIPAL TARGET OF PETROLEUM EXPLORATION IN THE FRONTAL PART OF THE KYLLAKH ZONE OF THE UPPER YANA FOLD AND THRUST BELT

A. V. Migurskiy, P. N. Sobolev

Two contrast highs were discovered within the sharply-folded relief of the Kyllakh zone frontal part, the Upper Yana fold and thrust belt, which hampered westward propagation of the allochton. The larger Mutula high is situated in the Belaya River basin in the conjunction zone of the Kyllakh and Ebeike-Khayata forethrust. The second high (Khamnylyma) occurs within the through of the Nelkan fore-thrust in the Yudoma River basin. The Mutula high is covered by seismic profiles defining its amplitude (more than 300 m) based on the bottom of the Vendian Yudoma Formation. The closed isohypse of –2000 implies the size of 32×18 km and area of about 450 sq. km. The position of the Mutula high exceptionally favours accumulation of hydrocarbons. HC migration toward the high occurred from the south, east, and northeast. A positive factor is the nearby occurrence of the Riphean pinch-out line to the northwest of the high, which complicates HC migration in this direction. Rejuvenation of the Mutula high itself during the allochton movement is also a positive factor for petroleum exploration, as the trap volume increases and new fracturing systems form, which results in increase of reservoir properties. All this implies that the structure can be considered as the major promising exploration target within the Fore-Sette-Daban trough. The paper includes the appraisal of localized resources of oil and gas. Calculation of localized HC resources within the studied structure has shown that the field is large. Up to 70.8 mln tons of oil and 136.4 bln m3 of gas are predicted there. Parametric drilling to the depth of 3200 m is proposed within the high to explore the section and petroleum potential of the Riphean, Vendian, and Cambrian deposits.

Key words: overthrusting, high, lateral migration, reservoir horizons, petroleum potential, HC resources.

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