Petroleum Provinces of the Paratethyan Region

Abstract

Initial crustal collision between Africa and Eurasia in the middle Eocene – early Oligocene enclosed a semi‐restricted Paratethyan seaway of linked basins and platforms across a region stretching from the Eastern Alps to the South Caspian Sea. As the African Plate continued to advance north during the later Neogene, the seaway shrank into a series of more isolated basins separated by the rising Alpine – Carpathian – Caucasus fold‐thrust belts. Organic‐rich oil‐prone Paratethyan source rocks of middle Eocene (Kuma Formation and equivalents) and Oligocene – early Miocene (Maikop and Menilite Beds) ages, and more gas‐prone post‐orogenic mid‐upper Miocene shales, subsequently charged over 2500 accumulations across the region with combined recoverable reserves of 95 billion brl oil‐equivalent (B boe). These accumulations are clustered in discrete petroleum provinces, each with a distinct tectono‐stratigraphic architecture and comprised of one or more petroleum systems. The provinces can be grouped into five broad categories: Average Reserves Average Field Sizes Fold‐thrust Provinces60,980 MMboe2–590 MMboeSub‐thrust Provinces255 MMboe3.4 MMboeForeland Provinces18,671 MMboe2–77 MMboeIntermontane Provinces13,122 MMboe1–40 MMboeBlack Sea back‐arc Province> 1391 MMboe>33 MMboe The productivity of each province (estimated very approximately from the number of barrels oil equivalent / square kilometre) is extremely variable, and its relationship with the geological factors controlling hydrocarbon entrapment and retention is complex. The most critical of these factors appears to be the quality and distribution of source rocks and post‐charge structural modification.

The Oligocene–miocene Menilite Formation in the Ukrainian Carpathians: A World‐class Source Rock

“…The Boryslav-Pokuttya petroleum system (sensu Boote et al, 2018) is located within the frontal part of the flysch belt ( Fig. 1b) which is the main oil-bearing area in the Ukrainian Carpathians.…”

“…1b) which is the main oil-bearing area in the Ukrainian Carpathians. The area hosts more than forty oil and condensate accumulations with total recoverable reserves estimated at 2249 MM boe (Boote et al, 2018). Structural traps consist of stacked duplexes; Paleogene and Miocene deep-water reservoir sandstones are sealed by the overlying Miocene molasse (Kotarba and Koltun, 2006).…”

“…The Skole-Skyba and Silesian-Krosno petroleum systems extend from Poland into western Ukraine. However, with estimated total recoverable reserves of only 200 MMboe (Boote et al, 2018), these systems are economically less important than the Boryslav-Pokuttya petroleum system. More than 80 relatively small oil and gas fields (most of them located in Poland) are hosted by Upper Cretaceous -Paleocene, Eocene and Oligocene sandstones within complex, faulted antiformal structures.…”

“…The Ukrainian Carpathians are one of the oldest petroleum-producing provinces in the world (Boote et al, 2018). Petroleum production began in 1854 with the discovery of the Boryslav oil field, one of the largest onshore oilfields in Europe (Kotarba et al, 2007).…”

Biomarker Geochemistry of Crude Oils and Neogene Bituminous Shales in the Yeniköy Area, Ereğli‐ulukișla Basin, Central Anatolia, Turkey

“…A combination of intense tectonic activity and a sea level fall resulted in isolation of the Paratethys at the Eocene -Oligocene boundary, with the subsequent episodic development of anoxic conditions (Popov et al, 2004). This resulted in the deposition of organicrich Oligo-Miocene sediments which are source rocks for hydrocarbons in several Paratethys regions including the Alpine Foreland basin, Carpathian Foredeep, Black Sea, Caucasus Foredeep and South Caspian Sea (Zeigler and Roure, 1999;Kotarba and Koltun, 2006;Sachsenhofer et al, 2015Sachsenhofer et al, , 2018Boote et al, 2018).…”