Technology of pumping production of high-viscosity oil with injection of coolant to the bottom through hollow rodsShamil Mingulov, Vyacheslav V. Mukhametshin, Lyubov Kuleshova, Alina Gizzatullina and Ruslan GilyazetdinovE3S Web Conf., 498 (2024) 03004DOI: https://doi.org/10.1051/e3sconf/202449803004