In terms of structure, we mainly focus on the improvement and development of gate valve, vigorously promote the use of wellhead equipment, and carry out reliability analysis and Research on the products. Wellhead equipment refers to Christmas tree, tubing head, casing head and related accessories used to hang, support, control and adjust production equipment. As an important equipment in oil and gas production, the performance of wellhead equipment is related to the production stability of oil and gas wells. A lot of research and development have been carried out at home and abroad, but the wellhead equipment at home and abroad still lags behind the international level. The composition, installation position, working principle and function of casing head, tubing head and Christmas tree are introduced respectively.The performance of wellhead equipment is related to the production stability of oil and gas wells. The development of petroleum industry puts forward higher requirements for the reliability and control of wellhead devices and valves, which promotes the continuous improvement and development of wellhead devices. For the whole wellhead equipment, the improvement of wellhead equipment mainly focuses on the reduction of size and weight, even the portability and flexibility;Wellhead device is a conventional wellhead device, in which casing head, tubing head, hanger, valve and other components are arranged in a standard way. The standard configuration of wellhead equipment can be customized according to the specification, wellhead device and casing program.

How to operate Christmas tree of wellhead equipment1、 Well opening (flowing well): 1. Ensure that the production system is complete and the flow is smooth, and the fluid after well opening can be accepted. 2. All valves on the Christmas tree are in the correct on-off state, and the nozzle (adjustable nozzle) is controlled. 3. Check the condition of wellhead oil pressure and safety equipment.2、 Shut in (flowing well): 1. 2. Close the wing valve. 3. Close the ground safety valve if necessary. 4. Close the main valve if necessary.3、 In some downhole operations, the operation steps of Christmas tree valve are as follows:1. Shut in the well (nozzle, wing valve, wax removal valve, surface safety valve and main valve) before running downhole tools.2. Open the Christmas tree cap, install the riser and BOP, and then pressure test the riser.3. Open the ground safety valve and lock the ground safety valve with a fusing thread cap. In the open position, test the reliability of the locking threaded cap.4. Lock the hydraulic control circuit of downhole safety valve and test its reliability.5. Open the main valve, and then open the wax removal valve.6. Label the locking parts of main valve, wax removal valve and safety valve to prevent other personnel from moving the valve at will.7. Downhole tools.8. Close the main valve and wax removal valve after the downhole tools are lifted up to the riser.9. Install Christmas tree cap after pressure relief and unloading of BOP riser,10. Remove the locking screw cap of the surface safety valve, open the hydraulic locking valve of the downhole safety valve, and remove the tag,11. Open the well according to the instruction.

The Christmas tree is a component located at the opening to the top of the well, including valves for measurement and maintenance, safety system and a series of monitoring devices. The Christmas tree connects the production pipeline and outlet pipe from the well, and acts as an important barrier to isolate the top of the oil well from the external environment. It includes a number of valves that can be used to regulate or prevent the steam, natural gas and liquid from flowing out of the well. The Christmas tree is connected to the production manifold system through subsea pipelines.There are many types of Christmas trees, which can be divided into water Christmas trees (placed on the platform deck) and underwater Christmas trees (placed on the seabed) according to the application area; vertical (or vertical) Christmas trees, horizontal (or horizontal) Christmas trees, and plug-in (or caisson) oil extraction trees according to the installation position; dry Christmas trees, wet Christmas trees and dry / wet Christmas trees according to the structural forms; and The layout of wells is divided into satellite well Christmas tree and chassis well Christmas tree.Christmas tree has the following functions:(1) Connect the casing of each layer, seal the annular space of each layer of casing, and bear the weight of casing.(2) Hang tubing and running tools to support the weight of all tubing strings in the well and seal the annular space between tubing and casing.(3) Control and regulate the production of oil wells.(4) Ensure the construction of various underground operations, facilitate the construction of well killing operation, lifting operation and other measures, and carry out daily production management such as pressure measurement and wax removal.(5) Record the data of oil pressure and casing pressure.Christmas tree is also called Christmas tree. A wellhead control device for testing oil and gas after completion of an oil (gas) well, or for oil recovery from flowing wells and mechanical production wells. It is composed of tubing hanger, many gates and tee or cross, and is directly installed on the casing head. A single wing Christmas tree is called a single wing Christmas tree if there is only one side of the oil pipe; it is called a double wing Christmas tree if there are both sides. The Christmas tree is equipped with choke, which can control oil and gas production by changing nozzles with different inner diameters.