The invention relates to an oil
recovery method of closed circulation and
viscosity breakback of hot oil in a
viscous oil well and a device; the method comprises the following steps of: putting the
crude oil into a
heating system of a special device, adopting two sets of systems with burning of
coal or gas or a single
system with burning of
coal or gas, being capable of adopting one well with one
system or a plurality of wells with one
system, and heating and injecting the
crude oil into the well for closed circulation. The device comprises a
heating system, a buffering tank, an injecting circulating system and an oil pumping system; the circulating system comprises a telescoped central
pipe and a telescoped outer sleeve; the telescoped central
pipe is sleeved into the telescoped outer
pipe, an opening of the lower end thereof is a free end and the upper end thereof is connected with a circulating valve, an injecting pipe, a surface flow pipe, a boosting pump, the buffering tank and the outlet of the
heating system in sequence; the lower end of the telescoped outer pipe is connected with the oil-well pump and the upper end thereof is connected with a polished rod, a drain pipe and the inlet of a heating system in sequence by a polished rod sealer; and the upper end of the circulating valve is connected with a polished rod eye of an oil pumping unit. The invention has the characteristics of good heat exchange performance, good
viscosity breakback, high pump efficiency, and the like and is widely applied in
viscous oil recovery technology.