Complete set of electric heating device in self-injection (gas) well
From the upper end of the Christmas tree (the place where the blowout preventer or the wax removal pipe was originally installed), the hollow sucker rod is vertically connected. The length of the hollow sucker rod is equal to the required heating depth, and enters the well through the wax removal gate valve and the main valve Tubing. A centralizer is installed on the top of the hollow sucker rod. All the dynamic and static sealing operation requirements will be reliably completed by oilfield professional technicians.
Pass the metal MI heating cable into the hollow sucker rod, and the hollow sucker rod bears its own weight, and the gap is filled with heat-conducting oil. Install wellhead fixings and flexible cables to connect to power sockets. The flexible cable is connected to the installed electric control box. When the metal MI heating cable is connected to the power supply, 100% of the heat generated by it is released in the tubing, so the thermal efficiency is very high.
Selection of heating cable model
Gas well information:
Goal—Relieve ice block in the 500m section under the Christmas tree (regular heating)
Gas production volume — 12,000 cubic meters/day, without sulfide.
Water production—0.7 cubic meters/day
Well pressure - 20Mpa
Core diameter=1.78mm; insulation=1.3; sheath=1.3 ; outer diameter=10.6mm;
3-core; copper sheath; thermal resistance=0.0069; weight 230Kg; the overall breaking force of the test is greater than 1000Kg;
The surface temperature of the cable sheath under working conditions (downhole) is above +80℃;
(Inoue) The surface temperature of the cable sheath is below +90℃;
Technical solution description:
The electric heating system in the blowout well that is finally installed is as shown in Figure 1
Figure 1 Electric heating system in the well
The project has three determined priorities:
Provide high-quality metal MI heating cable and component manufacturing.
The oilfield completes a tight and effective hollow sucker rod pressure-bearing sealing device.
Safe and reliable heating cable installation or extraction process.
General technical requirements for electric heating in blowout wells:
Self-blowout wellhead pipe pressure ≤20 MPa; metal MI heating cable hanging point breaking force greater than 10000N; hollow sucker rod inner diameter ≥Φ22mm; metal MI heating cable outer diameter Φ6~15mm; L≤ 1000m;
Heating depth 200--1000; Well exit temperature ≤80℃; Heating power 30--120Kw; Power supply voltage Three-phase 380/220 VAC; 660/380 VAC;
Use the metal MI heating cable to be dense and seamless, add a wellhead connector to the wellhead Christmas tree, and place the three-core metal MI heating cable single-point suspension into the hollow sucker rod in the tubing. The metal MI The evenly generated heat energy per meter of heating cable heats the oil (gas) medium in the oil pipe.
On-site installation and operation process
1. Site preparation
(1) The wellhead construction approval document has been issued;
(2) The construction site is leveled and closed. Idlers cannot enter and meet HSE standard requirements;
(3) The power supply connection point is completed;
(4) Security system access;
(5) All equipment arrives at the scene;
2. Construction preparation
(1) Inventory and inspection of equipment and tools;
(2) Place and anchor the turret on the metal heating cable reel;
(3) Erection of temporary scaffolds or operating platform ladders at the well head; (the roof of the well head can be used as the operating platform)
(4) Positioning and installation of temperature control box;
(5) Hollow sucker rod installation pup joints and installation joints are normal, and there is no obvious leakage. The working position of the Christmas tree is normal.
(6) Put the φ20mm steel ball head and steel cable slowly into the hollow sucker rod until the bottom of the hollow sucker rod. In
Make a mark on the exposed steel cable to measure the total actual depth in the rod and check it with the actual length of the supplied cable.
3. Construction and installation
(1) Check all installation parts and sealing materials.
(2) Install metal MI heating cable wellhead seals, wellhead brackets, and pulleys.
(3) Carry out a comprehensive linkage inspection of all operating instruments.
(4) The person in charge of the construction site of the owner issues an order to start the formal construction operation.
(5) Release the metal heating cable to the wellhead through the wellhead pulley, and thread all other parts at the end of the metal heating cable according to the sequence shown in Figure 2.
(6) Install the “wellhead connector”.
(7) Install special accessories “MI seal holder” (pay attention to add O-ring seal).
(8) A fixed amount of heat transfer oil is poured into the hollow sucker rod.
(9) Put in the sealed semi-hard fluorine rubber ring and the sealing copper gasket, and first tighten the MI sealing bundle head, and feel that the metal MI heating cable can still move up and down.
(10) Check the linkage of the metal heating cable into the fixture of the installer and the cable reel.
(11) The electrical performance data of the metal MI heating cable is qualified.
(12) Slowly feed the metal MI heating cable into the hollow sucker rod.
(13) Note: When the metal heating cable enters the hollow sucker rod for about 100m, an operator must be guarded by the cable reel to prevent and prevent the metal heating cable from being dragged into the well, and it should be damped under the control of external force The cable continues to enter slowly.
(14) When the predetermined metal MI heating cable has entered, and the cable body obviously releases its weight, it indicates that the design depth defined in the hollow sucker rod has been reached.
(15) Fasten the MI seal head, compression ring, and lock nut in place.
(16) Disassemble other installation aids, and complete the installation of the metal MI heating cable wellhead fixing assembly.
(17) Test the electrical performance data of the metal MI heating cable as qualified, and make a record.
(18) The final wellhead hollow sucker rod installation fixture is shown above:
(19) Connect the metal power socket, and lay the cold-resistant power cable buried in the steel pipe into the temperature control box to realize the power input preparation.
(20) Check again and there is no abnormality, put on the wellhead anti-damage protective cap, the installation process is completed, and you can enter the power transmission and debugging stage.