Iranian Scientists Find Secret of Unconventional Oil Reservoirs
A research team from the Faculty of Geology at the University of Tehran has succeeded in discovering a key mechanism in unconventional hydrocarbon reservoirs in the Abadan Plain area.
The research, led by Hamzeh Mehrabi, an Associate Professor at the University of Tehran, in collaboration with Elham Talebi, a PhD student at the Faculty of Geology, was published in the prestigious international journal Facies.
“The results of this research showed that although these rocks have high porosity, the bottlenecks between these pores are extremely narrow. This is as if the reservoir has imprisoned the oil in millions of tiny chambers that are very narrow and cannot be moved or extracted,” Mehrabi said.
“It was found that the quality of the reservoir is strongly influenced by the type of rock texture and the chemical changes that the rocks have experienced deep in the earth over millions of years, and that rocks that have been affected by dissolution by groundwater in the past have more open bottlenecks and are more suitable for extraction,” he added.
“These findings will help oil companies to significantly increase the extraction efficiency of these unconventional reserves by focusing on identified areas and using reservoir stimulation techniques tailored to the micropore characteristics (such as advanced hydraulic fracturing),” Mehrabi said.
Unconventional oil reservoirs are hydrocarbon accumulations in low-permeability rocks like shale, tight sandstones, and oil sands, where oil or gas is trapped by strong capillary forces rather than a distinct impermeable caprock.
Extraction requires specialized technologies, primarily horizontal drilling and hydraulic fracturing, to stimulate flow from the tight rock matrix into a productive wellbore. Examples include tight oil (oil in low-permeability formations), shale oil (oil within organic-rich shales), and heavy oil or oil sands (thick, high-viscosity oil trapped in sand).
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