Exploration in the Ukraine is turning toward the northwest shelf of the Black Sea and to the Sea of Azov. Initial hydrocarbon resources of the Sea of Azov are assessed at 343.8 million tons oil equivalent (2.3 BBOE). Two new fields have been discovered in the study area: Severo- Kazantip in the Sea of Azov and Bezymyan in the Black Sea. Also, a new gas-condensate pool has been found in Shmidt field in the Black Sea.
The Indolo-Kuban downwarp extends across the southern part of the Sea of Azov and into Kerchen Peninsula. Its Oligocene-Neogene basin fill is estimated at 8 km, and thickness of the Oligocene-Miocene Maykop as much as 5 km.
Severo-Kazantip is one of four structures in the Indolo-Kuban down- warp that have been prepared for driling. Three wells have now been drilled on this structure. Testing of wells 1 and 2 disclosed three gas- condensate pools in the upper Maykop. Well 1 bottomed at 1115 m and was tested in the 1026-1112 m interval, where gas was recovered at 84.5 thousand cu m (3 million cu ft) per day. Well 2 was drilled to a depth of 1400 m and disclosed two additonal productive horizons. This well yielded a gas-condensate mixture at 56 to 91 thousand cu m per day. Well 3 drilled in 1999 to 2600 m penetrated Neogene and upper and middle Maykop rocks, where geophysical logging indicates presence of the three upper horizons and in addition three prospective horizons associated with stratigraphic pinch out of Maykop beds.
The Oligocene-lower Miocene sediments (Maykop) consist of clays with members of sandy siltstone and sandstone. The reservoirs have porosity of 19-29 percent and permeability of 9-3450 md.
Gas resources of Severo-Kazantip field are assessed at 40 billion cu m (1.4 tcf).
Bezymyan gas field is located in the northwest part of the shelf of the Black Sea, where water depth is 37-39 m. It is on the northwest flank of Kiliy-Zmein high.
The Bezymyan structure was prepared for deep drilling on the lower Paleocene and middle Eocene sediments by seismic surveys in 1996. On Horizon IIIa at the top of the Paleogene this high is an anticline cut by a fault of northwest trend. On the closed -1175 m structure contour this high measures 6.5 by 3 km and has a closure of 25 m. Its area is 14.6 sq km. Gas resources are assessed at 2.92 billion cu m (102 bcf).
Exploration drilling began on Bezymyan structure in 1997. Well 1 bottomed at 1185 m, well 2 at 2258 m, and well 3 at 2055 m. Gas pays were found in the middle Eocene and lower Paleocene.
Testing of limestones in the lower Paleocene yielded flows of gas at 98, 79, and 96 thousand cu m per day from wells 1, 2, and 3, respec- tively. Methane content is 95 percent. Formation pressure at depth of 1081 m is 11.72 MPa.
Testing of the middle Eocene yielded flows of gas at 146 and 111 thousand cu m per day from wells 1 and 2, respectively. The gas is 97 percent methane.
It is now quite clear that the Ukrainian economoc zone of the Black
Sea and Sea of Azov has significant petroleum potential. (Taken from
Yevdoshuk and others, 2000; digested in Petroleum Geology, vol. 34,
no. 4, p. 342-346, 4 maps, in press)
Copyright 2000 James Clarke. You are encouraged to print out this
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