Post-salt trapping mechanism of south-east Pre-Caspian and its application to petroleum exploration

Abstract

The Kungurian saliferous sediments of the Pre-Caspian sedimentary basin represented by thick stratum of rock salt with interlayered lenses of anhydrites, terrigenous and carbonate rocks. Initial thickness of these sediments estimated as 4000–4500 m at the center of the depression and 1000–2000 m on the edges of the basin. The processes of halokinesis led to formation of more than 1200 salt dome structures represented by salt diapirs and walls, ridges and salt pillows. Number of salt dome related structures of Mesozoic clastic deposits revealed by seismic exploration carried out in 70–90′s of last century are quite common on the south-eastern part of the Pre-Caspian Sedimentary basin. Most of hydrocarbon pools in post-salt clastic rocks have been discovered on fault-related anticline prospects which are derived from salt tectonics morphologically variable (Munyithya et al. Petrol Explor Prod Technol 10: 2257–2267. https://doi.org/10.1007/s13202-020-00917-1, 2020). Other potential traps anticipated in the area are stratigraphic traps, pinch-out and unconformity-related traps, trapped by salt domes and walls or by salt overhang, etc.

Prospect evaluation based on integrated petroleum system analysis: Block E case study, south-eastern edge of Precaspian Basin (Kazakhstan)

“…The thick Kungurian diapiric salt section contains internal anhydrites, shales, carbonates, initial thickness of salts estimated as 1000-2000 m within the study area (Akhmetzhanov et al 2020). Salt tectonics has led to the The seismic reflector V (Fig.…”

“…No hydrocarbon accumulations have been identified in the inter-dome depressions yet. Cretaceous, Jurassic and Upper Triassic strata have been penetrated, logged and cored by numerous dedicated exploration and production wells and carefully characterized (Dalyan et al 1993;Kukhtinov and Crasquin-Soleau, 1999;Barde et al 2002;Zholtayev et al 2019;Akhmetzhanov et al 2020).…”

Some Features of Structural Interpretation of CDP 3d Seismic Data Under Conditions of the Bezymyannoye Field

“…The discovery of the Kenkiyak, Karatobe, Zhanazhol, Urikhtau, Karachaganak, Tortai and other oil fields in the subsalt complex led to the tendency to consider only subsalt deposits as promising for this area. However, during the last twenty years almost 15 oil and gas fields have been discovered, oil and gas content of which is mainly connected with the Mesozoic rock complex (Akhmetzhanov et al, 2020(Akhmetzhanov et al, :2653Kunin et al, 1978:29). The largest of the newly discovered fields is Kenbai, the productivity of which is associated with terrigenous sediments of the middle Triassic (1,050-1,386 m).…”

“…Sandy reservoirs are porous, terrigenous with an open porosity of 17.8%. The reservoir is topped by claystone with a thickness of 15 to 50 m (Akhmetzhanov et al, 2020(Akhmetzhanov et al, :2653Bekzhanov et al, 2000:395;Kunin et al, 1978:29).…”