How was the long-distance pipeline built?

When we like to watch the rolling "oil dragon" and "gas dragon" galloping in the pipeline, have you ever thought about how every steel pipeline is built?

When an oil transportation or gas transmission pipeline project is determined, the route selection is to select the route through which the pipeline passes before the designer designs the pipeline. Its basic trend, distance and complexity of ground conditions (whether there are deserts, rivers, mountains and rivers, swamps, etc. ) Determine the workload, material consumption and construction difficulty of oil transportation or gas transmission pipeline project. Secondly, reconnaissance, go to the selected route (select several possible route schemes on appropriate scale map and aerial photography) and inspect its geography, landform and geology on the spot. Used to use old instruments, the workload was heavy, the labor intensity was high, and the task was quite hard. With the development of new technology, surveyors can obtain accurate and detailed data with the help of powerful technical means such as aerial remote sensing, remote sensing and computer, which provides a guarantee for choosing the best route. For example, in the design of natural gas pipeline from west to east, the "3S" technology, which integrates satellite remote sensing (RS), geographic information system (GIS) and global positioning system (GPS), was applied to the route selection design stage of pipeline engineering for the first time, and the traditional route selection and alignment method was improved, so that the pipeline route avoided the complex terrain along the route as much as possible, effectively reducing the difficulty of engineering construction and improving the work efficiency and data accuracy. Through the comparison and optimization of pipeline route, the line length is shortened from 4 167 km to 3900 km, saving investment of 2.7 billion yuan.

After the pipeline design is completed, the construction drawings will be handed over to the construction party (such as Western Pipeline Company), and the construction party will select the oil and gas pipeline construction team-Oilfield Engineering Construction Company to carry out the construction according to the drawings.

Desert often contains oil and natural gas, such as Tazhong Oilfield in Taklimakan Desert, Xinjiang. The main problem of pipeline crossing desert is that sand dunes move with the wind, and the pipeline may be blown away, resulting in large suspension, which will cause deformation and even fracture. There are two main preventive measures: choose the route direction-avoid the pipeline in the same direction as the local wind frequently, and avoid the mountain pass with strong wind; In addition, measures should be taken to prevent wind and fix sand. Sand-fixing belt-grass squares, sand barriers, planting sand plants, etc. It should be buried properly to prevent the pipeline from being blown away by the wind. In Karamay Oilfield, the principles and methods of pipeline route selection with characteristics in desert, Gobi, desert and general sections have been formed. Characteristic technologies such as Gobi gully erosion, seasonal river crossing, hydraulic protection in Gobi area, wind prevention and sand fixation in desert area have been formed.

If the area where the pipeline passes is in mountains and swamps, it can only be forced through. So what methods can be taken to ensure the safe construction and operation of pipelines in these areas?

When the pipeline passes through the mountainous area, it is necessary to choose a relatively flat area to pass through. The pipeline should be "settled" on hillsides and hilltops (to ensure long-term safety), and each position should be relatively flat with little slope. When the pipeline climbs, it usually climbs directly along the slope, because there is pressure in the pipeline and it is straight. When the pipeline is dug and buried, some slope protection, retaining wall, stone dam and cement pier shall be made at the same time. Should be set to stabilize the position of the pipeline. If the pipeline route is to be bypassed far away, it is necessary to tunnel (commonly known as karst cave) at a suitable location and take a shortcut to shorten the length of the pipeline.

The surface of the swamp area is water and the bottom is silt. To ensure that the pipeline passes through such an area, it is necessary to press concrete blocks, sandbags and other heavy objects on the pipeline, or directly bury the pipeline in the dense soil layer below the silt.

Pipeline construction carried out by oilfield engineering construction companies generally includes the following contents:

(1) survey and setting out: determine the location of the center line of pipeline installation on site and delimit the construction area; (2) Line sweeping: clean up the construction operation area along the line, and establish the site conditions for transportation and installation for pipeline installation; (3) Trench excavation: the earthwork excavation of the buried pipeline is completed; (4) Pipeline transportation: transporting steel pipes to the construction site; (5) Prefabricated elbows: according to the design requirements and site conditions, prefabricated elbows with various curvatures and angles; (6) Pipe laying: arranging steel pipes one by one on the installation line; (7) Pipeline assembly: align and weld steel pipes as required; (8) pipeline welding: welding a single steel pipe into a pipeline; (9) Weld flaw detection: check the quality of weld on site by various means; (10) Anti-corrosion and heat preservation: coat the outer wall (inner wall) of the pipeline with anti-corrosion and heat preservation; (1 1) joint coating: anti-corrosion insulation layer should be made at the girth weld of the pipeline; (12) Leak detection and repair: check the damaged parts of pipeline anticorrosion and thermal insulation layer and repair them according to the requirements of specifications; (13) Trenching: hang the welded pipe in the specified position in the trench; (14) Backfill: bury the pipeline in place in the ditch; (15) pressure test: add specified pressure into the pipeline with liquid or gas, and check the strength (bearing capacity) and tightness (check for leakage) of the pipeline; (16) ball-passing and line-sweeping: use water or compressed air to push the pig ball through the pipeline to remove the dirt inside; (17) landform restoration: clean up the site and restore the original landform along the line.

In this way, a pipeline was paved and a pipeline project was completed. The crude oil "oil dragon" and natural gas "gas dragon" in Karamay Oilfield reached Dushanzi and Urumqi, and the crude oil and refined oil "oil dragon" continued to extend to Lanzhou.