Research On The Auxiliary Balance For Beam Pumping Unit Based On CNC System

As one of the main oil production equipment, pumping unit has been working for the oilfield more than one hundred years. Although the new type of pumping unit appears constantly, and new production equipment and technology update constantly. The beam pumping unit is still the mainstay of oil extraction equipment because of its simple structure and convenient operation. In spite of this, the prominent problem of energy consumption of beam pumping unit is still unable to solve effectively for a long time. Especially the international crude oil is dropping in price recently, which affects the oil production profit of enterprise seriously. Many companies are forced to pay more attention to lower costs of production, and find a much more cost-effective method for petroleum exploration and development activities. Among them, the most important thing is to solve the problem of energy consumption of pumping unit.There are many factors that can affect energy consumption of pumping unit. The main reason causing beam pumping unit excessive consumption is imbalance. That is to say, the balance weight block of pumping unit is not enough to matched load torque completely generated by the load. It has to do with the complex borehole conditions, and also affected by the structure characteristics of the pumping unit four-bar linkage. There is no effective measure to improve the downhole condition. But it is feasible to improve the counterbalance effect of pumping unit by adding auxiliary equipment. It’s a higher requirement for the mechanical device to cope with the complex downhole conditions in real-time and accurately. The existing balance adjustment way of pumping units is gathering data, then carrying out the adjustment measures according to the empirical formula or other method. The test method is not accurate. The measure is difficult to operate and hard to ensure the effect of equilibrium. And it also can’t be adapt to changes of downhole conditions. The adjustment of pumping unit still requires regular inspection. It wastes time and energy. Most of the energy-saving reconstruction by variable frequency technology and other controller is still can’t be popularized and applied because of the low degree of automation, poor reliability and large modification cost is insufficient.With the progress of science and technology, and the domestic numerical control technology is developing rapidly. To improve the innovation ability and efficiency of mechanical products in our country, the national MIT wants to promote the application of numerical control technology in various industrial areas during "the 12th Five-Year", namely" CNC generation "project. It provides a good opportunity to realize the transformation and upgrading of oil field equipment for our country. In view of the bad counterbalance effect of the existing beam pumping unit.This research designed a set of beam pumping unit auxiliary balance control system. The system can analyze the balanced state and adjust the balance device of pumping unit regularly and automatically. The innovation point of this article is that:choosing the HuaZhong numerical control system whose technology is relatively mature to apply to the balance of pumping unit for the first time. By the powerful motion control ability, it can control several sets of pumping unit balance device at the same time, and realizes the remote monitoring and management. The auxiliary balance control system can effectively solve the problem of pumping unit need artificial adjustment on a regular basis. The control mode of "one-to-many" can reduce the reconstruction of the pumping unit costs except the high adjustment accuracy and counterbalance effect.The project aims at realizing the balance of beam pumping unit automatically and precisely. This article analyze the basic theory of beam pumping unit, including the structure composition of the pumping unit, working principle, the characteristic of four bar linkage, the motion law of polished rod, and the polished rod load. Based on this, the three balance principle is used to deduce the formula for the adjustment of the pumping unit auxiliary balance. With the powerful mathematical processing ability of VB, the balance calculation software of the pumping unit is completed. Combining with the calculated formula, this paper discusses the complexity of two types of auxiliary balance mode, and confirms that the beam auxiliary way is the best one. According to this, the hardware and software of control system are designed. By the method of upper machine, the HuaZhong HNC-808M CNC system is selected as the control core and the HSV-160U series servo drives and servo motor are the basic equipment. In VC environment, the remote operation and management of control system is realized with the aid of the secondary development function of the numerical control device.The debugging and test of the whole system is completed on the pumping unit in the laboratory. Through the comparative analysis of laboratory data, the results conform to theory, and show good counterbalance effect. It’s confirmed that the oil machine auxiliary balance control system scheme is feasible. The test environment and conditions is less complex than the oil field, but the test is still has reference value and guiding significance for actual application.