Statistical analysis of the relative position of the rod hanger and the wellhead

Keywords: downhole rod pumping unit, balancer, eccentricity, Rayleigh distribution


One of the leading methods of exploitation of oil fields is oil production with the help of downhole rod pumping units (DRPU). Over 80 % of the operating well stock of Azneft PA is equipped with deep well pumps and about 30 % of oil is produced in the country with their help.

The widespread use of DRPU is associated with a fairly high maturity of installations, simplicity of its design and maintenance, repair in field conditions, ease of adjustment, the possibility of servicing the installation by unskilled workers, a small effect on the operation of DRPU of the physical and chemical properties of the pumped liquid, as well as high efficiency.

However, along with the high efficiency of the applied DRPU, there are also complaints regarding the need to increase the reliability and resource of wellhead equipment, including in order to improve the environmental situation in the oil fields.

One of the conditions for ensuring high reliability of the ground equipment of the DRPU is to ensure the tightness of the wellhead rod-wellhead stuffing box assembly, the violation of which is not only a failure of the installation, but also leads to environmental pollution.

This is facilitated by inaccuracies in the assembly and installation of DRPU at the wellhead. When mounting the pumping unit, for many reasons, the tolerance of the wellhead rod with the suspension point of the rod string to the balancer head is not ensured.

In this regard, in the requirements for the accuracy of mounting the pumping unit at the point of application, a certain mismatch of the axes within the circular coordinates is allowed. So, for widely used pumping units of the CK8 type, the permissible mismatch between the axis of the wellhead rod and the suspension point of the rods is determined by the conditions under which the projection of the suspension point of the rods onto the plane of the base of the pumping unit at any position of the balancer is allowed within a circle with a diameter of 25 mm.


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Author Biographies

Ibrahim Habibov, Azerbaijan State Oil and Industry University

Department of Industrial Machines

Sevinc Abasova, Azerbaijan State Oil and Industry University

Department of Industrial Machines

Vusala Huseynova, Azerbaijan State Oil and Industry University

Department of Industrial Machines


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How to Cite
Habibov, I., Abasova, S., & Huseynova, V. (2022). Statistical analysis of the relative position of the rod hanger and the wellhead. EUREKA: Physics and Engineering, (2), 82-90.