--> Shale Gas in Western Ukraine – Hype Versus Hard Facts

AAPG ACE 2018

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Shale Gas in Western Ukraine – Hype Versus Hard Facts

Abstract

Following the shale gas hype in Poland around year 2010, the southern extension of the Lublin Basin into Ukraine caught attention by local and international players. Although only limited information about the Western Ukrainian shale gas potential was available, Ukrainian authorities delineated a 6,300 square km big and elongated NNW-SSE trending license area, Oleska, just in front of the slope from Silurian/Ordovician shallow marine carbontes to deepwater shales. Gas production from the Oleska field was hoped to start by 2015, reaching volumes of 5 bcm per year, and possibly increase to as much as 10 bcm per year. Oleska’s total gas potential was estimated at 1.5 trillion cubic meters, not knowing how much of these deposits were technically recoverable.

Our study group analyzed some 100 randomly collected core samples from 21 old wells from Precambrian to Devonian shales. Main interest was focused at Ordovician to Silurian rocks in depths between 1085 and 4400 meters. Parameters studied were: total carbon content, total inorganic content, sulphur content, vitrinite reflectance measurements / random reflectivity of organic matter, mineralogic composition and illite crystallinity. Integration of all checked maturity parameters documents major lateral and vertical maturity trends. Differentiation of a super mature area from those belonging to the oil respectively gas window is possible – these trends follow narrow and slope parallel stripes from the Ukrainian / Polish border via Lviv to about Ivano Frankivsk.

TOC values range between 0.1 and 1.3 weight percent which is considered very poor to poor. Analysis of selected logs from 31 wells indicates potential for shale gas at different stratigraphic levels.

Conclusion: low TOC contents in Silurian / Ordovician mudstones suggest a limited shale gas potential, while interpretation of logs from 31 wells indicates occasional existence of ‘hot shales’. The gas window is reached in depths between 3 and 4 km in the northwestern part of the Oleska area. Although several old wells reached the ‘gas shales’ no declared ‘shale gas well’ has been drilled yet, no economic producibility has been proved. Shale gas exploration in Oleska was terminated before it really started.