A student of the Electrical Engineering Faculty at Perm Tech has developed technology for heating wells to reduce oil viscosity. The heater, which helps pumps to lift black gold out of the well, will work more efficient with this technology. It will allow heating oil in a more economical way. The effectiveness of its usage in one oilfield is estimated at ? 5.5 million.
“The amount of low viscosity oil in Russia is too small, that is why high-viscosity oil fields are being developed now. Primary oil recovery is the process of extracting oil via the natural rise to the surface, which depends on the natural factors. When natural pressure is not enough to drive oil out of the well, it is necessary to change the method of oil extraction. Secondary recovery techniques maintain reservoir pressure by injecting water or gas. Liquids displace oil rests toward the wellbore. When it is impossible to use these methods, oil workers use enhanced oil recovery methods in particular thermal or chemical injection,”- tells us Dmitry Pinyagin, the first-year MSc student in Electrical Engineering faculty.
In this case the most effective method is the thermal treatment of the well’s bottom-hole zone with electric heaters. As the oil temperature increases, the oil viscosity decreases. It makes the oil extraction easier.
By the way, electric centrifugal pumps, which are used in the oil well, work better if the oil viscosity is low. And it is one more reason why it is necessary to decrease oil viscosity. Pumps have viscosity limits. The heating technology is well known, but numerical calculations of method’s effectiveness were made by the student for the first time.
“Our 2D mathematical model can decrease the oil viscosity in a specific place with the help of the heater. It can notably reduce costs. Now a cable, which provide with hydrocarbon flow, is used as the heater. This cable can also decrease the oil viscosity. But it is not as effective as the heater because its installation requires significant financial investments,”- says the student.
A research team studied distribution processes of viscosity, speed and temperature on 105-meter-long field in front of the pump in the oil well. They created 3 versions of the model with 20-meter-long and 40-meter-long heaters, which laid on the depth of 80 meters and 60 meters. Researchers used ICEM CFD и Ansys Fluent programs to create these models. As a result they got viscosity, speed and temperature data in the whole oil well and found out how oil temperature depends on heater power, its sizes and depth. Developers also determined the dependence of the temperature at pump inlet on the liquid volume and the distribution of oil viscosity on the depth from the well’s bottom to the pump. It helped them to choose the most efficient way of oil extraction.
The student believes that this method can be used in oil-production enterprises, which plan to reduce financial costs by developing oilfields.