Reservoir Characterization of the Pliocene Red Series, Lam Field and Surrounding Areas, Offshore Western Turkmenistan

Abstract

The sedimentology, petrography and reservoir potential of Pliocene sandstones within the Upper Red Series in the offshore LAM field, Western Turkmenistan, have been examined. Depositional settings are interpreted within the framework of the Red Series palaeoenvironments across the entire Turkmen sector of the Apsheron-Prebalkhan uplift zone, including its onshore extension to the east.Examination of 81 m of core from three separate intervals suggests that the Red Series in the LAM field is the product of a fluvial-dominated delta system with associated floodplain deposits, periodically flooded by the saline waters of the South Caspian Lake. Relatively thick sandstones, up to around 5 m thick, are interpreted as channel and pointbar deposits of a meandering river system, with thinner and finer-grained sandstones and siltstones inferred to be crevasse-splay and interdistributary floodplain deposits. Floodplain mudstones display signs of desiccation, soil formation, plant rootlets and occasional thin layers of anhydrite. Intervals with marine trace-fossil assemblages record incursions of saline-lake waters. Conglomeratic layers at the base of thicker mudstone intervals may be associated with abrupt transgressions of the lake. The best reservoir qualities are associated with the fluvial channel and point-bar sandstones. Crevasse-splay and other overbank sandstones are of poorer quality, while intercalated floodplain to lacustrine claystone/siltstone units may constitute local seals.Eighteen sandstone plug samples from the cored intervals were examined in thin-section and by XRD and SEM to assess how mineralogy, grain size and diagenesis affect reservoir quality. The samples consist predominantly of lithic arkoses and feldspathic litharenites; higher porosities, and therefore better reservoir potential, are associated with the feldspathic litharenites. Primary controls on porosity include compaction, clay-matrix content and calcite cementation. XRD data reveal the presence of illite, illite-smectite and chlorite. The presence

Experimental Investigation of a Self-adaptive Thickening Polymer Performance under High-Temperature–High-Salinity Reservoir Conditions

“…The geological background and reservoir characterization of the targeted field have been well summarized by Qi et al 18 and Rabbani et al 19 Based on field data, representative core plugs cut from Gray Berea sandstone outcrops were chosen for the polymer core-flood experiments. Sixteen core plugs (batch 1) were used for the formation damage test, and 10 core plugs (batch 2) were used for the polymer core-flood oil displacement efficiency study.…”

The Arabia – Eurasia Collision Zone in Iran: Tectonostratigraphic and Structural Synthesis

“…To the NW, this fault zone passes into the Apsheron-Balkhan uplift (or "sill"), a positive structure (e.g. Rabbani et al, 2023) which in the west constitutes the northern boundary of the South Caspian Basin (Lyberis and Manby 1999;Brunet et al, 2003). Further south, the western Kopeh Dagh foldbelt merges with the eastern Alborz (Figs 1 and 7c).…”

A Synthesis of the Geology and Petroleum Geology of the Iranian Portion of the South Caspian Basin and Surrounding Areas

“…1), and consists of a string of en échelon anticlines which host oil and gas fields. Reservoir rocks in fields in the Turkmenistan sector of the Apsheron-Pribalkhan Zone are dominated by the Pliocene Red Series which are equivalent of the Productive Series, Cheleken Formation and Brown Beds in other parts of the South Caspian Basin (Rabbani et al, 2023). Berberian (1983) estimated that as many as five fields may be discovered in the Iran Onshore-Nearshore portion of the South Caspian Basin on the basis of palaeogeographic maps showing the extent of the Maikop Group source rocks in the subsurface.…”