What are the methods for replacing and repairing oil and gas wellheads?

With the continuous improvement of process technology, there are more and more models of oil production. Due to the different structure and models of oil production trees, workover methods and steps are also different. In order to improve the development effect and realize the development policy of oil production with pressure, it is often implemented to use oil production trees with top threaded flanges instead of oil production trees without top threaded flanges. According to the different types and methods of on-site repair and replacement of oil production trees, there are mainly the following two repair methods for oil production and gas wellheads:

1. Restoration method of oil tree without top wire flange

The main difference between the top wire flange production pair and the non-top wire flange oil production tree is that it can be combined with the wellhead device that does not kill the well and does not blow out to form a well killing facility, which can perform well killing operations, while the latter does not kill the well and blow out. The wellhead device cannot perform well killing operations. The repair and replacement methods of the non-top wire flange oil production tree are determined according to the specific conditions of the well and the material conditions of the field equipment. Generally, the following two methods are used.

(1) Killing blowout prevention replacement method.

This method is to use the function of well killing to obtain smooth construction conditions. The specific oil production and gas wellhead step is to remove and replace the wellhead at the killing well. The high-pressure liquid in the well is stable and reliable, and the use of well killing fluid to kill well is not prone to blowout accidents, but its disadvantage is that the well killing fluid is used, especially the high-density well killing fluid, which not only causes a large amount of material consumption, but also easily injects pollutants into the oil layer. Reduce oil production and water injection after plugging the oil flow channel to repair the well or water well.

(2) Replacement method of packer seal.

The principle of using this method to replace the oil tree is to use the sealing function of the packer, and the oil and gas production wellhead cooperates with the interior and wellhead to temporarily prevent the oil and gas in the wellbore section from being ejected, thereby replacing the pressure operation to replace the wellhead oil tree.

2. Oil tree repair method with threaded flange on top

(1) Carry out oil and gas production wellhead construction design. According to the specific situation of the construction well and the content that needs to be repaired, the specific construction content, methods and steps are compiled according to the construction purpose and requirements, and protective measures are formulated at the same time.

(2) Run the YouTube plug. First close the main gate of the oil tree, put the plug into the well with the cooperation of the sewage pipe, and press the pressure with a high-pressure cleaning truck. Only after confirming that the YouTube pass is blocked can the next process be carried out.

(3) Lift the wellhead. After confirming that the plug is sealed, try to release the overflow observation. When there is no spray at the wellhead, hurry up and remove the oil tree. Remove the oil tree with the wellhead screws.

(4) Repair or welding. Repair work according to engineering construction requirements.

(5) Install the oil tree. After the wellhead components and equipment are repaired, the oil tree should be installed in time. Pay attention to tightening the screw jack on the screw jack flange to prevent YouTube blockage caused by high pressure in the well.

(6) Salvage plug. After the wellhead fault is repaired, the plug in the well is salvaged with power equipment and put into production again.