During drilling production, when crude oil transfers from the reservoir through the tubing and the pipeline to the gathering station, due to heat loss, the crude oil temperature is lower than the critical temperature for its thick, wax, hypercoagulability and other poor physical properties, which will cause the flow of wax deposition, sudden increasing viscosity, flow pressure reduction, resulting in mining problems. “Thermal recovery” uses the ides that during the infusion process, heat resource conducts heat exchange with crude oil (heavy, wax, condensation) through the carrier so as to supplement heat loss, overcome the above problems and achieve the purpose of smooth mining.
1.As it is with constant power, high-power, high energy consumption, adjustment of gradient heating is not allowed along with the change of downhole temperature. Therefore, large-scale promotion will be inappropriate except for increase of secondary cost.
2.As constant power products cannot overcome irrational structure design, it has short service life, usually no more than six months, which means maintenance or replacement, and the actual economic benefit is not significant.
3.The complex control device has more problems, inconvenient to operate. controling the temperature by power on and off, and because of limited on-off times, one time failure could easily lead to cable overheating, even major accidents (especially gas well).
4.All equipment are complicated, inconvenient to install, construct and maintain.
5.Long-term use of thermo-chemical oil recovery is expensive and will pollute the crude oil, increase subsequent production costs, which is only suitable for one-time processing.