The wellhead is the production hub of the oil well, and it is the part of the surface that forms the entire oil well. Whether it is a self-blowing wellhead device or a pumping well device, their main function is to suspend the tubing string and bear the weight of all tubing strings in the well; seal the annular space of tubing and casing to ensure the smooth progress of various downhole operations and control and adjust the production and admission data And daily management. Therefore, the performance of the wellhead device is of great importance to the oil well. With the increase of oilfield development time, due to natural conditions, external and human factors, the wellhead equipment will be damaged to varying degrees. In order to maintain the normal production of the oil well, find out the cause of the damage to the oil wellhead, analyze the influencing factors, and repair in time , Is an important work for workover.

Due to the different types of wellheads, there are many types of wellhead devices, and the specific conditions of each well are different, so there are many types of wellhead failures. However, wellhead failures can be summarized by the words "thorn", "leakage", "bad" and "dead". The main phenomena are as follows:

1. thorn

The manifestation of this kind of old-fashioned phenomenon is that the gate, the flange and the joint are pierced with oil or water. Generally, there are less on oil wells and more on water wells. This is because the pump pressure on the ground is very high when water injection is performed. Therefore, the performance and pressure requirements of the equipment are very strict. If some parts of the wellhead device are not well sealed or the gasket is damaged, it is easy to cause wellhead thorns. In some cases, long-term high-pressure water injection causes serious corrosion of equipment, loss of function of sealing parts, and thorn phenomenon, which prevents normal production of oil and water wells.

2. (seepage) leakage

This kind of failure is due to the seepage or oil (or water) dripping of the wellhead equipment components, due to the deterioration of the long-term performance of the equipment, or because the threaded parts are damaged during maintenance, and there is no tightening. Or leak out. This phenomenon not only pollutes the environment, is inconvenient to manage, and affects the normal production of oil wells, but it is also unsafe and prone to major accidents.

3. Bad

Damage to equipment or components will reduce the function of the wellhead device and fail. The main reasons for the damage to the wellhead device (or equipment) are accidental damage during production and maintenance, as well as damage during downhole workover. Because of improper management system or violation of operating procedures, wellhead equipment will also be damaged.

4. Die

This kind of failure phenomenon is equipment inflexibility or necrosis, the reason is due to knocking, or loss of maintenance and lubrication and rust to death, but also due to pollution and corrosion liquid caused by not clean. It makes the operation of the wellhead device inflexible, and even loses its function, which affects the smooth progress of production and operation. If the gate of the wellhead gate falls off, the threaded buckle is bent and rusted, it cannot be used normally.