Petroleum Geology and Resources of the North Caspian Basin, Kazakhstan and Russia By Gregory F. Ulmishek U.S. Geological Survey Bulletin 2201-B U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director Version 1.0, 2001 This publication is only available online at: http://geology.cr.usgs.gov/pub/bulletins/b2201-b/ Manuscript approved for publication May 24, 2001 Published in the Central Region, Denver, Colorado Graphics by Susan Walden and Gayle M. Dumonceaux Photocomposition by Gayle M. Dumonceaux Edited by L.M. Carter Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Contents Foreword ....................................................................................................................................... 1 Abstract ......................................................................................................................................... 1 Introduction .................................................................................................................................. 2 Province Overview ....................................................................................................................... 2 Province Location and Boundaries ................................................................................ 2 Tectono-Stratigraphic Development.............................................................................. 8 Present-Day Structure ...................................................................................................... 8 Total Petroleum System.................................................................................................... 8 North Caspian Paleozoic Total Petroleum System ................................................................. 9 Overview.............................................................................................................................. 9 Discovery History...............................................................................................................9 Petroleum Occurrence...................................................................................................... 9 Stratigraphy of Subsalt Upper Paleozoic Rocks........................................................... 9 North and West Basin Margin................................................................................ 10 East-Southeast Basin Margin................................................................................. 10 South Basin Margin.................................................................................................. 10 Source Rocks...................................................................................................................... 17 Reservoir Rocks .................................................................................................................19 Seal Rocks........................................................................................................................... 19 Traps .................................................................................................................................... 21 Assessment Units .............................................................................................................. 21 Assessment Unit 10160102, North and West Margin Subsalt Barrier Reefs ............................................................................................................. 21 Assessment Unit 10160101, North and West Margin Subsalt Pinnacle Reefs .......................................................................................................... 21 Assessment Unit 10160103, East and Southeast Margin Subsalt..................... 22 Assessment Unit 10160104, South Margin Subsalt ............................................. 22 Assessment Unit 10160105, Basin Center Subsalt .............................................. 23 Assessment Unit 10160106, Suprasalt................................................................... 23 References Cited ......................................................................................................................... 23 Figures 1. Map showing petroleum system and assessment units of North Caspian basin ...................................................................................................... 3 2. Structural map of North Caspian basin...................................................................... 7 3–6. Cross sections: 3. Through north basin margin ................................................................................... 11 4. Through Karachaganak carbonate buildup......................................................... 12 III 5. Through east basin margin .................................................................................... 13 6. Of Karaton-Tengiz zone ........................................................................................... 14 7. Sketch map showing areas of carbonate buildups of northern Caspian Sea .... 15 8. Cross section of Astrakhan arch................................................................................. 16 9. Events chart of North Caspian Paleozoic Total Petroleum System ...................... 18 10. Tectonic map of northern part of east basin margin and adjacent Ural foldbelt .................................................................................................................... 20 Table 1. North Caspian basin, province 1016 assessment results summary— allocated resources...................................................................................................... 4 IV Petroleum Geology and Resources of the North Caspian Basin, Kazakhstan and Russia By Gregory F. Ulmishek Foreword Region, single digit 3 Province, three digits to the right of region code 3162 Total petroleum system, two digits to the right of This report was prepared as part of the World Energy province code 316205 Project of the U.S. Geological Survey. In the project, the world Assessment unit, two digits to the right of petroleum was divided into 8 regions and 937 geologic provinces. The system code 31620504 provinces have been ranked according to the discovered oil and The codes for the regions and provinces are listed in U.S. Geo- gas volumes within each (U.S. Geological Survey World Energy logical Survey World Energy Assessment Team (2000). Assessment Team, 2000). Then, 76 “priority” provinces (exclu- Oil and gas reserves quoted in this report are derived sive of the U.S. and chosen for their high ranking) and 26 from Petroleum Exploration and Production database (Petro- “boutique” provinces (exclusive of the U.S. and chosen for their consultants, 1996) and other area reports from Petroconsult- anticipated petroleum richness or special regional economic ants, Inc., unless otherwise noted. importance) were selected for appraisal of oil and gas resources. A map, figure 1 of this report, shows boundaries of the The petroleum geology of these priority and boutique provinces total petroleum system and assessment units; it was compiled is described in this series of reports. using geographic information system (GIS) software. Political The purpose of this effort is to aid in assessing the quanti- boundaries and cartographic representations were taken, with ties of oil, gas, and natural gas liquids that have the potential to permission, from Environmental Systems Research Institute’s be added to reserves within the next 30 years. These volumes ArcWorld 1:3 million digital coverage (1992), have no political either reside in undiscovered fields whose sizes exceed the significance, and are displayed for general reference only. Oil stated minimum-field-size cutoff value for the assessment unit and gas field centerpoints, shown on this map, are reproduced, (variable, but must be at least 1 million barrels of oil equivalent) with permission, from Petroconsultants, 1996. or occur as reserve growth of fields already discovered. The petroleum system constitutes the basic geologic unit of the oil and gas assessment. The total petroleum system includes all genetically related petroleum found in shows and accumula- Abstract tions (discovered and undiscovered) that has been generated by a pod or by closely related pods of mature source rock. This The North Caspian basin is a petroleum-rich but lightly petroleum exists within a limited mappable geologic space, explored basin located in Kazakhstan and Russia. It occupies together with the essential mappable geologic elements (source, the shallow northern portion of the Caspian Sea and a large reservoir, and seal) that control the fundamental processes of plain to the north of the sea between the Volga and Ural Rivers generation, expulsion, migration, entrapment, and preservation and farther east to the Mugodzhary Highland, which is the of petroleum. southern continuation of the Ural foldbelt. The basin is An assessment unit is a mappable part of a total petroleum bounded by the Paleozoic carbonate platform of the Volga-Ural system in which discovered and undiscovered fields constitute a province to the north and west and by the Ural, South Emba, single relatively homogeneous population such that the chosen and Karpinsky Hercynian foldbelts to the east and south. The methodology of resource assessment based on estimation of the basin was originated by pre-Late