The X-mass tree is a wellhead device used to extract oil from wells and machine wells. It is the main equipment for controlling and regulating oil and gas production in the upper part of oil and gas wells. It mainly consists of casing head, tubing head and oil (gas) X-mass tree body.
The X-mass tree is a component that opens to the top opening of the well, including valves for measurement and repair, safety systems, and a range of monitoring instruments. The X-mass tree connects the production and outflow pipes from the downhole and serves as an important barrier to the isolation of the top of the well from the external environment. It includes a number of valves that can be used to regulate or prevent the production of crude oil vapors, natural gases and liquids from the well. The X-mass tree is connected to the production manifold system through a submarine pipeline.
There are many types of X-mass tree in the production X-mass tree. According to the application area, it is divided into water X-mass tree (placed on the platform deck) and underwater X-mass tree (placed on the seabed); according to the installation position, it is divided into vertical (or vertical) X-mass trees and levels ( Or horizontal) X-mass tree, plug-in (or caisson) X-mass tree; divided into dry X-mass tree, wet X-mass tree and dry/wet X-mass tree according to structure; divided into satellite well X-mass tree and chassis well according to well arrangement Christmas X-mass tree.
Open well (self-injection well):
Ensure that the production system is complete and the flow is smooth and the fluid after opening the well can be accepted.
All valves on the X-mass tree are in the correct state of switching and control the nozzle (adjustable nozzle).
Check the state of the wellhead oil pressure and safety equipment.
Shut the well (from the well):
Close the nozzle.
Close the wing valve.
Close the ground safety valve if necessary.
Close the main valve if necessary.
In some downhole operations, the operation steps of the X-mass tree valve are as follows:
1. Close the well (oil nozzle, wing valve, wax cleaning valve, ground safety valve and main valve) before entering the downhole tool.
2. Open the X-mass tree cap, install the riser, blowout preventer, and then stand the test.
3. Open the ground safety valve and lock the ground safety valve with a blown threaded cap on the safety valve. In the open position, test the reliability of the locking screw cap.
4. Lock the hydraulic control circuit of the tubing downhole safety valve and test its reliability.
5. Open the main valve and open the clear wax valve.
6. Put labels on the main valve, clear wax valve and safety valve lock to prevent other personnel from moving the valve.
7. Go down to the underground working tool.
8. After the downhole work tool refers to the riser, close the main valve and clear the wax valve.
9. After the blowout preventer rises and is removed, install the X-mass tree cap.
10. Remove the locking screw cap of the ground safety valve, open the hydraulic lock valve of the tubing safety valve, and remove the tag.
11. Open well production according to the instructions.
The components of the X-mass tree are mainly composed of tubing heads, tubing hangers, flanges and some valves. The valve mainly has a grease nipple (throttle valve), a production wing valve, a wax cleaning valve, a main valve and a casing valve;
The tubing head is mounted on the uppermost casing head for supporting the tubing string gravity and sealing the annulus between the tubing and the casing. Tubing head working pressure: 1000, 2000, 3000, 5000, 10000, 15000, 20000 psi. The rated temperature is -18 ° C - 121 ° C. When the completion is completed, the rated working pressure of the tubing head is generally selected as the formation fracture pressure, and is matched with the rated working pressure of the tubing.
The tubing hangs the fuel tubing string in the cone seat of the tubing head and provides a means of sealing between the tubing and the cone. Generally, there are conical oil pipe hanging, eccentric oil pipe hanging with cable through hole, self-sealing oil pipe hanging and double oil pipe hanging. There is a BIW cable crossing on the tubing, two 1/4inNPT hydraulic control pipeline crossings, and a 3/8in NPT chemical injection port. The tubing is attached to the 4-1/2 inEUE threaded port.
The upper flange is between the tubing head and the tubing cross. The lower flange has 1inLP pressure tap and 1inLP injection hole.
The tubing cross is composed of a clear wax valve, a main valve and a production wing valve. It is an integral oil X-mass tree, and the lower flange is connected to the upper part and the oil X-mass tree cap is connected thereto.
The X-mass tree cap is installed on the top of the X-mass tree to clear the wax valve, which is used to provide quick access to the tubing space from the longitudinal direction. If the wire operation, coiled tubing operation, production test, switch sleeve, loading and unloading back pressure valve are performed, first Remove the X-mass tree cap. The bottom of the X-mass tree cap is an API flange or thread.
The X-mass tree has the following effects:
(1) Connect the casings of the underground wells, seal the annular space of each layer of casing, and bear the weight of the casing.
(2) Suspending the oil pipe and the downhole tool, supporting the weight of all the fuel pipe columns in the well, and sealing the annular space between the oil pipe and the casing.
(3) Control and regulate the production of oil wells.
(4) Ensure the construction of various underground operations, facilitate the construction of well operations, start-up operations, etc., and carry out daily production management such as pressure measurement and wax removal.
(5) Record oil pressure and casing pressure data.
The X-mass tree is also called the Christmas X-mass tree. A wellhead control device for oil and gas testing after oil (gas) well completion, or for oil recovery from wells and machine wells. It consists of a tubing hang and many gates and tees or crosses that are mounted directly on the casing head. Only one side of the oil X-mass tree with a fuel pipe, called a single-wing X-mass tree; both sides have a fuel pipe, called a two-wing X-mass tree. The X-mass tree is equipped with a grease nipple (nozzle) that controls the production of oil and gas by replacing the nipples of different internal diameters.