What are the methods of using Christmas trees?
The methods of using Christmas trees involve many aspects, including their installation, commissioning, normal operation, maintenance and special operations such as shutting in and opening wells. The following is a detailed description of the methods of using Christmas trees:
1. Installation and commissioning
Installation:
Before installing the Christmas tree, it is necessary to inspect and accept the quantity and appearance of the product parts according to the packing list, drawings and other materials.
Refer to the drawings in the instruction manual for installation. All fasteners should be tightened symmetrically and must not be installed less or missed.
During the installation process, special attention should be paid to the position and connection of the tubing head, tubing hanger, flange and each valve to ensure sealing and stability.
Commissioning:
Before use, an overall sealing pressure test is required. The specific steps include tightening the plugs on the threaded flanges connected to the throttle valves at both ends, opening all valves, pumping the pressure to the working pressure by the pressure test flange and stabilizing the pressure for a certain period of time (such as 3 minutes), and checking whether there are leakage, sweating and pressure drop in each component and its connection.
2. Normal operation
Valve operation:
The valves on the Christmas tree mainly include nozzles (throttle valves), production wing valves, wax removal valves, main valves and casing valves. During normal oil production, the main valve and the wing valve on one side are usually in the normally open state, while the wing valve on the other side and the wax removal valve of the small four-way are in the normally closed state.
The throttle valve is used to adjust the flow rate and perform stepless speed regulation by rotating the handwheel. After adjustment, the valve stem needs to be locked to prevent loosening.
Pressure monitoring:
The Christmas tree is also equipped with a pressure gauge to monitor the oil pipe pressure. When the oil pipe pressure needs to be measured, the small handwheel can be opened to allow the working medium to enter the pressure gauge for measurement. If the pressure gauge needs to be installed or replaced, close the handwheel before operating.
3. Maintenance
Regular inspection:
Regularly check the tightness and sealing performance of each component of the Christmas tree and the abnormality of the downstream pipeline.
Regularly check whether the valve has air leakage, and check the switching performance of the Christmas tree valve in stages according to relevant operating procedures.
Cleaning and lubrication:
Clean the oil and debris on the surface of the Christmas tree and keep it clean.
Add an appropriate amount of lubricating oil (such as lithium-based lubricating oil) to the oil cup on the valve bearing seat to ensure that the bearing rotates flexibly.
Quarterly regular maintenance:
Inject sealing grease (such as 7903 sealing grease) through the sealing grease injection valve on the valve bonnet to lubricate the valve plate and valve seat and enhance the sealing performance.
IV. Special operations
Well shut-in operation:
When the well needs to be shut down, close the nozzle, wing valve, ground safety valve and main valve in a certain order. The specific operation steps may vary depending on the type of Christmas tree and actual conditions.
Well opening operation:
Before opening the well, it is necessary to ensure that the production system is complete and the process is smooth. Check whether the status of all valves on the Christmas tree is correct and control the opening of the nozzle. Then open each valve in a certain order to resume production.
V. Precautions
During the operation, the safety operating procedures and the requirements of the Christmas tree's instruction manual should be strictly followed.
It is strictly forbidden to operate or adjust the Christmas tree when it is in a half-open and half-closed state.
When performing special operations such as shutting in or opening a well, a detailed operation plan should be prepared in advance to ensure personnel safety.
Through the use and maintenance of the above methods, the normal operation of the Christmas tree can be ensured and its service life can be extended. It also helps to improve the production efficiency and safety of oil and gas wells.