The Buzuluk depression is located in the southern part of the Volga-Ural oil-gas province. Within it the top of the basement subsides from a depth of 3.5 km in the north to 5.7 km in the south. At the base of the sedimentary cover is a Devonian clastic complex about 500 m thick. Normal faulting has broken this terrane into three large structural steps of east-west trend: North to south these are Kamelik-Chagan zone of highs, Rubezhin downwarp, and a zone of block highs. These structural steps are in turn cut by north-south faults into four blocks. From west to east they are the Vishnev, Zaykino-Rostashin, Livkin-Tsarev, and Lebyazhin-Ak'yar. In spite of extensive study and no small number of discoveries, the Middle-Upper Devonian of the Buzuluk depression remains an important exploration target. The focus of this study is largely on the Kamelik-Chagan zone of highs. The Eifelian-Frasnian clastics of this zone are classified as oil-source beds on a basis of content of organic carbon. Low values of generating potential of this organic matter indicate that maturity of the oil-generation process has already been achieved. Characteristic of the organic matter of all the tectonic blocks is similarity of quantitative and qualitative indexes of the disseminated organic matter. For example, in the bitumoids of both limestones and argillites a maximum is found in the region of n-alkanes C-15 - C-17. The ratio of pristane to phytane is 0.5-0.8. These parameters indicate a predominance of marine algae as the source of the organic matter. Hydrocarbon pools have been found in Devonian clastics in (upward in the section) Biy-Aftonin (Stratum V), Vorob'yev (Stratum IV), Ardatov (Stratum III), and Pashiy (Stratum I) Horizons. Depth to the Upper Devonian increases from 2939 m on the north to 3895 m in the south. Present formation temperature ranges from 59.5 to 80.0 degrees C, and formation pressure from 25.5 to 46.9 MPa. For the Middle Devonian pools the depth interval is 3303-5307 m, formation temperature is 75-107 degrees C, and formation pressure is 37.2-58.8 MPa. Gas saturation of the oils of Stratum I ranges from 48 to 427 cu m per ton, and density is 0.82-0.84. Somewhat better quality oils are found in Strata V and IV, where the gas saturation is 87-7532 cu m per ton and density drops to 0.767-0.842. Downward along the section there is a shift in the alkanes to a dominance of more low-molecular compounds: There is an increase in the share of n-alkanes C-13 to C-20 in comparison with C-21 to C-30. There is a systematic increase in thermal maturity of the hydrocarbon systems both down the section and from east to west for same-age strata in each block, In spite of small differences in depth of occurrence of these Devonian rocks, there is a rather broad range in phase state in Strata V, IV, and III, due to different levels of thermal maturity and intensity of tectonic movements. In Stratum V pools of gas-condensate-oil with a paraffin base can be expected on the Livkin-Tsarev block. Gas-condensate-oil and oil pools are predicted for the Lebyazhin-Ak'yar block. Light volitile oil is expected on the Zaykino-Rostashin block, and gas condensate on the Vishnev block. Stratum IV is very favorable for gas-condensate-oil pools on the Vishnev, Zaykino-Rostashin, and Livkin-Tsarev blocks and for light oil on the Zaykino-Rostashin and Lebyazhin-Ak'yar blocks. Oil pools are expected in Stratum II on all the blocks (Taken from Chakhmakhchev and others, 1998; digested in Petroleum Geology, vol 33, no. 3, 1999; 1 map and 2 geochemical diagrams). Copyright 2000 James Clarke. You are encouaged to print out this News Letter and to forward it to others. Earlier News Letters are available at: http://geocities.com/internetgeology/ Inquiries concerning the journal Petroleum Geology can be made by telephone at (703) 759-4487, or by FAX at (703) 759-3754,