Fingerprinting and biomarker analysis of oil from Akshabulak group for determining oil types

Abstract

This article presents the results of fingerprinting of 128 oil samples derived from all production wells of three Akshabulak group fields to determine the types of oils. Based on the results of this analysis, four groups of oils were identified: The first group includes oils (red) of the lower hydrocarbon pay zones (III-IV-V) in Akshabulak Central, the upper zones of the I southern dome of Akshabulak Central and all pay zones of the northern dome at Akshabulak South. The second group of oils (green) was identified in the wells exploiting pay zone I in the northern dome of Akshabulak Central, while oils (blue) in the productive horizons of Akshabulak East and paleochannel sediments of Akshabulak Central form the third group. The fourth group includes one oil sample with different genesis from well № 37, which penetrates paleo-channel № 13 at South Akshabulak. Biomarker analysis was carried out for 39 oil samples, according to which the oils were formed in terrigenous (clayey) organic matter, deposited in lacustrine environment. In terms of thermal parameters, the oils of the Eastern Akshabulak are less mature than the oils of the Central Akshabulak and the South Akshabulak, despite their relative deeper depths. Based on the work performed, the conclusion presents the prospective hydrocarbon accumulation zones suitable for increasing hydrocarbon resources and reserves in the future. However it should be noted that the results of the studies performed provide valuable information only when integrated with the corresponding geological and seismic data.