HYDROCARBON HABITAT OF THE DNIEPR-DONETS DEPRESSION

The Dniepr-Donets Depression forms part of the Pripyat-Dniepr-Donets-D onbass-Karpinsky aulacogen that evolved as a Devonian rift. The post-r ift subsidence of this basin was interrupted during the late Early Per mian when its southeastern parts were partly inverted. Further inversi on pulses straddle the Jurassic-Cretaceous and the Cretaceous-Tertiary boundaries. The Dniepr-Donets Depression hosts the most important hyd rocarbon province of the Ukraine. At the beginning of 1994, ultimate r ecoverable reserves in established accumulations (past production and remaining reserves) amounted to about 170 x 10(6) t of oil and gas-con densate and 980 x 10(9) m(3) gas. The bulk of oil and gas accumulation s is contained in Carboniferous to Early Permian post-rift series. Sou rce-rocks occur in Devonian syn-rift and Carboniferous post-rift serie s; these attained maturity prior to basin inversion. Hydrocarbon accum ulations are characterized by multiple reservoir-seal pairs. The matur e syn-rift Devonian and the immature post-inversion series contain onl y minor hydrocarbon accumulations. Oil and gas accumulations are mainl y trapped in syn-rift, salt-induced and inversion-related structures. The latter received their hydrocarbon charge mainly due to inversion-i nduced destruction of pre-existing accumulations and ensuing re-migrat ion of hydrocarbons. Basin inversion, depending on its intensity, can enhance the trapping potential of a basin or causes destruction of maj or hydrocarbon resources. Post-inversion subsidence, depending on its magnitude and the amount of syn-inversion erosion, can induce a second phase of hydrocarbon generation and the charging of inversion structu res. However, this mechanism, which contributed, for instance, to the hydrocarbon habitat of inverted basins in the Southern North Sea, was not effective in the Dniepr-Donets Basin. (C) 1998 Elsevier Science Lt d. All rights reserved.