Development of technologies for the pour point depressant treatment of an annular near-wall layer of oil pumped through a main pipelineM.D. Bisengaliev, A.T. Zholbasarova, A.R. Togasheva, R.Y. Bayamirova and M.D. SarbopeevaE3S Web Conf., 288 (2021) 01005DOI: https://doi.org/10.1051/e3sconf/202128801005