Deposition of asphaltenes and resins in production strings of oil wells is a widespread and objective phenomenon at some oilfields. Deposits are formed due to the change of pressure and temperature conditions of oil: in the production string temperature and pressure drop to the critical level, paraffins start to crystalize and deposit on the production string walls. Unfortunately, for some types of oils it is impossible to choose an adequate inhibitor out of the whole range of chemicals available in Russia. Such problematic wells are treated with the solvent of asphalt, resin and paraffin deposits.

Coiled tubing is considered to be the most advanced treatment technology. Coiled tube is run into the well via the production string or annulus. In the latter case CT is run to reach a downhole pump, then the needed volume of solvent is injected through the CT and subsequently pumped into the production string with the help of downhole pump.

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