An international research group, which included scientists from the Perm Polytechnic University, presented a unique domestic composition of polymer gel, which will increase the completeness of oil reserves production.
Professor of the Missouri University of Science and Technology (USA) Baojan Bai and specialists of the NefteProm Service enterprise also took part in the work of the international research group. The research results are published in the peer-reviewed Russian scientific journal "Notes of the Mining Institute". The development has no analogues in the world.
“Now at many fields where oil has been producing for a long time, wells are flooded: the water content in the production exceeds the norm. According to the audit of the Volga-Ural oil and gas fields, 75% of the reserves account for more than half of water. Meanwhile, for high-water-cut wells, a decrease in the water cut of even 5% can increase oil production by one and a half times. This is a tremendous technological effect,”says the Dean of the Mining and Petroleum Faculty of PNRPU, Doctor of Geological and Mineralogical Sciences, Professor Sergei Galkin.
Over the past two decades, the world has been using PPG technology - preformed particle gel to increase oil production. A suspension based on particles of a preliminary "crosslinked" polymer is pumped into the well. It is based on acrylamide, which absorbs water, increases in volume and makes the substance elastic. During filtration, the polymer particles are compressed and torn in narrow intervals between the beds. They form a "plug" that redistributes filtration flows, "displaces" oil and increases its production.
The author of the method, Professor of the Missouri University of Science and Technology (USA) Baojan Bai, has successfully carried out more than 4000 well operations in the fields of China, Central and North America. For domestic deposits, this technology is still practically not used. Only in Western Siberia there is very limited experience of its application in the conditions of high-temperature reservoirs (60 °) with low salinity of formation water. However, for the territory of the Volga-Urals, at low reservoir temperatures (less than 30 °) and increased water salinity, the compositions developed to date do not absorb water well.
Therefore, experts from PNRPU and the NefteProm Service enterprise have synthesized a unique domestic composition. It was created on the basis of polyacrylamide by block polymerization. The gel completely absorbs water even at temperatures below 30 ° C. In comparison with the known technologies, the Permian gel swells at least twice as much, filling the channels washed with water, in which there is no longer any oil.
"The difference between the polymer developed by Perm scientists is its crosslinking method by thermal imidization, as a result of which the polymer can absorb more water even at low temperatures and increased mineralization of formation water," notes Sergey Galkin.
Scientists conducted experiments on rock samples from a well. Tests have shown that swollen gel particles can penetrate cracks 20 times smaller in diameter. As the viscosity of the gel increases, its strength increases. The substance “cements” the channels from which oil has already been produced and through which water flows intensively; as a result, water flows are redistributed and water displaces oil from the still undeveloped intervals.
“The technology, in my opinion, is not only capable of providing a significant increase in oil production, but also has good commercial prospects, as it is focused on the vast territory of the Volga-Ural oil and gas province. In addition, this domestic technology, and, accordingly, the subsoil user in this case is insured against unexpected reversals of foreign partners in the context of political sanctions,”said Pavel Ilyushin, head of the Perm REC“Rational Subsoil Use”, Ph. D.