The original anti-corrosion insulation structure of a single well pipeline for heavy oil injection and production in an oil field is coated with high-temperature anti-corrosion coating on the outer wall of the pipeline. The insulation material is made of double-layer composite silicate tile, and the outer sheath is made of asphalt glass cloth or elastic polyurethane coating. Due to the large number of joints in the original insulation structure, the outer sheath is easily damaged when the steam is injected at high temperature, which causes the water in the outer sheath to enter, and the combination of high water content and corrosive ions in the buried pipeline area causes the original The anti-corrosion insulation structure fails quickly, and the pipeline corrosion heat leakage is serious. In response to this situation, a new type of anti-corrosion insulation structure has been developed. The new thermal insulation structure makes up for the shortcomings of the original thermal insulation structure with many seams and poor water resistance. It only needs to be repaired on the spot, which reduces the workload and improves the working efficiency.
1Structure design 1.1 Straight pipe section insulation structure design The outer wall of the pipe is coated with high temperature and anticorrosive paint, and the insulation layer is made of soft silicate composite silicate insulation material. The soft thermal insulation material is a composite silicate thermal insulation felt, and the hard material is a hard support ring compressed by the composite silicate thermal insulation felt, which can support the outer sheath and the pressure resistance in the thermal insulation structure. The outer sheath is made of polyvinyl chloride double-walled hollow corrugated pipe (hereinafter referred to as PVC corrugated pipe). Direct pipe section insulation structure shows advice.
1 one outer double wall hollow bellows: 2 soft composite silicate insulation material; 3 - hard composite silicate support ring; 4 an anti-corrosion coating; 5 working tube straight pipe section insulation structure schematic 1.2 The rubber bellows is filled, and its structure is seen.
4 rubber corrugated pipe; 5 - hard thermal insulation material; 6PVC corrugated pipe joint structure to indicate the specific construction steps of the mouth is as follows: (1) before the working pipe is welded, the rubber bellows is sleeved at one end.
(2) Welded and polished to ST3 level within 50mm of both sides of the working tube, and coated with high temperature anticorrosive paint after dust removal.
(3) After the coating is cured, the insulation is carried out, and the insulation material and structure are the same as the soft section of the straight pipe section.
(4) At least two or more grooves of the rubber bellows and the PVC corrugated pipe are overlapped and overlapped. In the overlapping groove of the PVC bellows, the silicone glass sealant is applied circumferentially. The top of the sealant should be higher than the groove of the PVC pipe. The top is 2mm or more.
(5) The inner ring of the outer surface of the rubber bellows overlaps with the PVC bellows and is tightly sealed with a tightening hoop.
2 Field application and effect test 2.1 Construction effect evaluation All the insulation pipelines in the new insulation structure can be used in the factory pre-water hammer elimination device Renhehai Xu Shiqin Zhongyuan Oilfield Design Institute Road System, a series of rapid hydraulic impact caused by sudden changes in water flow rate . Stopping the pump water hammer is extremely threatening to the pump house and pipeline. It is simple and effective to set up the water hammer to eliminate the tank to reduce the water hammer of the pump. Using the HAMMER software, it is calculated that each pump station needs to be equipped with a water hammer to eliminate 4 sets of water hammers in order to effectively eliminate the impact of water hammer. The water hammer elimination tank has the advantages of flexible application, safety and reliability, and convenient maintenance, and is worthy of promotion in domestic and foreign projects.
In recent years, the Zhongyuan Oilfield Design Institute has designed more and more international long-distance water transport projects, such as the Sudan Port Water Supply Project, the Nyala Water Supply Project and the Saudi Ministry of Agriculture Water Pipeline Project. These long-distance, high-lift, multi-undulating pressurized water delivery systems have complex transient hydraulic characteristics, and the comprehensive protection of water hammers in pumping stations and pipelines is a subject worthy of consideration and research. Therefore, the design of the water pipeline should fully consider the various water hammer phenomena that may occur in the actual operation of the project, so as to take corresponding technical measures.
1 water hammer formation cause water hammer, he called water hammer refers to a series of sharp changes caused by sudden changes in water flow rate in the pump and piping system due to sudden power failure or other reasons caused by sudden power failure or sudden stop of the pump unit Hydraulic impact phenomenon. Stopping the pump water hammer is extremely threatening to the pump house and pipeline.
The size of the pump-stop water hammer is related to the specific arrangement of the pump and the water pipeline in the pump house. Therefore, it should be filled when designing the pump room and the water pipeline, and only the joints are connected at the site, which is less affected by the environment and simple in construction. High efficiency and construction quality are more easily guaranteed.
2.2 Evaluation of heat preservation effect In this test, a temperature probe is pre-embedded on the outer wall of the pipeline, and the temperature probe wire is led to the ground during backfilling for measurement. After 1 year of installation, the field test was carried out. The test data is shown in Table 1. Table 1 Pipe outer wall temperature test data Well number Test position Test result / C Remarks Three-way straight pipe section Bent pipe wellhead temperature: 77 °C Station temperature: 68 ° C Elbow wellhead three-way straight pipe section elbow wellhead temperature: 86 °C station temperature: 79 °C elbow wellhead From the test results, the highest temperature of the outer wall of the pipeline is the wellhead or tee, the lowest temperature is the bend, it can be seen The temperature of the outer wall of the pipeline is basically the same as the soil temperature of the buried pipeline. There is no obvious heat leakage, and the heat preservation effect of the pipeline is better.
At the same time, the wellhead and the station temperature test were carried out on the pipeline of the original insulation structure. The test results show that the oil temperature in the 80-station oil well temperature is 60C, the temperature difference between the well stations reaches 20 C, and the temperature difference of the well station of the new insulation structure is less than 10 C. Under the condition of the well station distance, the insulation effect of the new insulation structure is good. In the original insulation structure.
3 Conclusion For the particularity of heavy oil buried injection pipeline, a new type of double-wall corrugated pipe anti-corrosion insulation structure was developed. The structural insulation pipe can be used for factory prefabrication except for the other processes. The new insulation structure has been tested by field application. The temperature in the station is 79C at the well oil temperature of 86C and the ambient temperature is 4.5C. The maximum temperature of the outer wall of the buried pipeline is at the wellhead or tee, and the lowest temperature is the bend. There is insulation structure, the new insulation structure can reduce the pipeline temperature by 10C, the temperature inside the station is increased by 10C, and the heat preservation effect is good.
Zhang Yanjun: Graduated from Tianjin University in 2003, majoring in industrial catalysis, and now works at China Petroleum Group Engineering Technology Research Institute.
(The column is hosted by Fan Yuhua)
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