Yangtze University's submersible pump unit diagnostic project passed expert appraisal

At the appraisal meeting organized by the Science and Technology Department of Hubei Province in mid-March, the Yangtze University's “Diagnostic Technology for Comprehensive Working Conditions of Submersible Electric Pump Units” was identified by the expert group. Professor Huang Xuhua, an academician of the Chinese Academy of Engineering, and other experts believe that this innovative achievement is of great significance for promoting the technological advancement of the petroleum industry.

In the past, the traditional method of diagnosing the fault of submersible electric pump at home and abroad was limited to the unilateral diagnosis of the underground electric pump, that is, the multi-stage centrifugal pump. When the well condition changes (such as the reduction of the output liquid discharge, the electric pump is pumped dry). The sudden increase of formation gas displacement causes a series of faults such as electric pump air plugs. Traditional diagnostic methods cannot accurately judge or even determine the cause of failure. This problem plagues scientists in the petroleum field.

Prof. Feng Ding from the School of Mechanical Engineering of Yangtze University has taken a unique approach, taking the submersible motor, cable, protector and submersible electric pump as a whole, taking full account of the working parameters of the electric pump unit, the well trajectory, the physical and chemical properties of the produced liquid, Under the conditions of formation conditions and other factors, the concept and method of comprehensive diagnosis are proposed, and a comprehensive diagnosis model is established. Since 2004, this comprehensive diagnostic method and model has been used in 430 oil wells in Bohai Oilfield and Jianghan Oilfield, with an average shortening of the pumping cycle of 60 days, an increase of 435,000 barrels of crude oil, and a cumulative direct economic benefit of more than 300 million yuan.

Generally, in the case of shallow wells, relatively simple working conditions, and good well trajectory, the use of conventional pumping units is more efficient. However, when the working conditions are more complicated, the pump is deeper, and the well trajectory is more complicated, the conventional pumping unit cannot work normally. Since the beginning of the 1980s, foreign countries have begun to use submersible electric pumps to extract oil. Because of its ability to be used in complex well conditions, especially horizontal wells, directional wells, deep vertical wells, and with large displacement and flexibility, applications The effect is good, the application range and market share are gradually improved.

At present, the market share of foreign submersible electric pumps is about 30%. China's use of submersible electric pumps for oil production is only a matter of nearly a decade. The current market share has reached 27%, making it the second largest lifting equipment for oil exploration.

The working environment of the submersible electric pump is extremely complicated. In addition to petroleum, the production fluid extracted from the ground contains a large amount of water, gas, sand and corrosive medium, and the ambient temperature increases with the increase of the well depth. These harsh environments It often causes the submersible electric pump unit to malfunction, which seriously affects oil production.

At present, the comprehensive working condition diagnosis technology of this submersible electric pump unit is being promoted and applied in Daqing Oilfield, Dagang Oilfield and Shengli Oilfield. The Canadian Petroleum Corporation also plans to introduce this new technology.