Mangistau Basin SW Kazakhstan – General Geology
The Mangistau Sub-basin is located in western Kazakhstan bordering the Caspian Sea. It has an onshore component which is 300 km long and 100 km wide.
It is a large unpopulated Asian steppe with little vegetation due to low rainfall. Temperatures are extreme, ranging from +40 to -40 degrees Celcius. The surface conditions for seismic and field development however are ideal due to easy terrain with a tiny cultural and environment footprint.
The Petroleum Geology can be simplified to a Triassic failed NW-SE rift forming horsts and grabens and a syn-rift Jurassic clastic sequence topped by a Tertiary to Cretaceous shale cover.
Fig 1 – Overview of the Mangistau Sub-Basin, Kazakhstan
Fig 2 – USGS Regional Cross Section highlighting the Zhetybai Area
Petroleum production and future prospectivity is almost exclusively in the Triassic horsts and the draping Jurassic sandstones.
Fig 3 – Stratigraphic Chart showing the Active Petroleum System
Total reserves for the basin is in excess of 5 Billion barrels including two giant oil fields Uzen and Zhetybay. Remaining potential is estimated by Jupiter and the USGS at 10-100 mmstb per discovery.
In the past wells were located on 2D seismic which was very successful in finding the simple 4 way dip domes in the Jurassic but did not fully define the more structurally complex Triassic fault blocks. Recent 3D surveys have revolutionized the knowledge base and led to many new oil discoveries and the revitalization of many old oil fields.