Геофизический журнал (Apr 2024)
Prospectivity of Pliocene-Miocene deposits of the Khasilat field of the Absheron oil and gas bearing region according to surface and well seismic data
Abstract
The article begins with a history of commercial hydrocarbon production in the Absheron Peninsula, which is one of the oldest oil and gasbearing regions in the world. Despite the long exploitation of hydrocarbons here, this region has a strong industrial potential, especially in the lower Pliocene and underlying sediments. A lithological-stratigraphic boundary separating the Qala Suite of the Productive Series into two parts has been delineated by a Well Logging complex. The lower part is most likely represented by sandstones deposited during the transgressive phase of development of this part of the peninsula, while the upper part is characterized by complete and incomplete regressive cycles. The boundary of stratigraphic unconformity was marked, and also the boundary of thermobaric system change can be synchronously connected with it. As for the older sediments, their prospectivity is indicated by commercial production of hydrocarbons in the adjacent areas. An indirect indication of oil and gas prospects of the underlying fields is the identification of a zone of Abnormal Formation Pressure in the Khasilat field according to the Vertical Seismic Profiling results of two wells. The results of reinterpretation of 3D seismic data are widely reported in the article. Temporal thickness maps suggest a large river delta in the area during the formation of the Qala Suite deposits. Obviously, the appearance of numerous deltaic channels and straits was associated with gentle slopes and shallow depths of the coastal part of the basin where the delta was formed. Based on the constructed map of temporal thicknesses between the seismic horizon confined to the QaS-2 and SH-IV strata, which in the conventional time scale represents the paleorelief at the start of the formation of the Qala Suite deposits, the most favorable areas for the accumulation of sandy sediments were determined.
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