Analysis of horizontal directional drilling construction technology for oil pipeline
With the development of science and technology, horizontal directional drilling technology also has rapid development, in terms of the actual situation, this paper takes horizontal directional drilling construction technology as the background of the study, and also makes a scientific analysis of its principle, and then summarizes the characteristics of horizontal directional drilling construction technology for oil pipelines, to provide some reference for the application of horizontal directional drilling construction technology in oil pipelines.
1. The working principle and introduction of horizontal directional drilling
The principle of horizontal directional drilling is to guide and detect the measured area with the aid of a directional drilling rig and a guide instrument. The directional drilling rig has a very high guiding effect, and when the drill bit reaches the required depth for construction, the wedge-shaped drill bit can be switched to a conical reamer device to achieve the construction requirements more precisely. Horizontal directional drilling rig is a tool for laying utilities underground without digging up the surface of the ground. It is widely used for special geological situations such as sandy soil and clay, but it is not applicable to strata with high water table, etc. In China, most areas can be constructed using horizontal directional drilling technology. The construction environment temperature can be carried out from -15 – 45℃. The current development trend is also diversified development, such as: large-scale, miniaturization, ultra-depth guided monitoring, etc., so the application of horizontal directional drilling will be more and more widely.
2. Characteristics of horizontal directional drilling construction
- (1) Nowadays, when we talk about construction, people have the impression that the construction site is noisy. However, when horizontal directional drilling construction, it will not cause obstruction to the traffic, nor will it cause damage to the vegetation at the construction site, nor will it affect the normal living order of the people around. In this mode, the noise of traditional construction mode will not appear, and the impact on the surrounding environment is minimized. For example, when burying pipes in cities and encountering underground riverbeds, horizontal directional drilling technology can cause no damage to the surrounding environment.
- (2) As the horizontal directional drilling bit reaches the corresponding depth, you can switch the bit to continue the operation, modern construction equipment construction accuracy is very high, more convenient for the laying and adjustment of the pipeline, better to meet the needs of construction, and can make the pipeline more scientifically around the underground obstacles.
- (3) Horizontal directional drilling technology is also not affected by the season, and compared to traditional construction methods, the labor required is less, the operating process is much higher than the traditional mode, and due to the extremely high precision and accuracy of the instrument, the success rate of construction is high, and less safety hazards after completion.
- (4) Horizontal directional drilling construction method in and out of the site required a short time, high efficiency, and can be flexible according to the actual construction site fine-tuning, it requires a relatively low cost compared to other modes, not only to achieve the purpose of cost savings, but also to improve construction efficiency.
- (5) After the survey of the construction geology is completed, the pre-expansion holes installed by the horizontal directional drill can be drilled to the expected size of the construction according to 1.3-1.5 times of the pipe diameter.
3. The defects of horizontal directional drilling construction
- (1) Because the horizontal directional drilling construction is a new technology combined with the traditional construction technology, so this technology is not fully mature, and there is no unified technical reference standard. Therefore, it is difficult to accept and identify its works.
- (2) Because the horizontal directional drilling is not backfilled like the traditional trenching and laying construction, so this has extremely high requirements for the construction metal material settlement, making it a certain risk in the actual use.
4. Characteristics of oil and gas pipelines in China
Because of the complex landscape in China, different regions have different geological features, so the characteristics of oil and gas pipelines in China are also more tedious. By March 2020, the length of oil and gas pipelines in China has been 150,000km, new natural gas pipelines amounted to more than 30,000km, while new crude oil pipelines amounted to 10,000km. according to this development trend, the construction of oil and gas pipelines is still a top priority. Since the country has continuous investment in oil and gas construction, many new construction technologies have emerged. In the process of technology development, it is not only the innovation of technology, but also the qualitative improvement of China’s oil construction technology. Today, the efficiency of pipeline transportation in China has increased by 20 points compared with the efficiency of traditional pipelines in the past. Although the transportation of China’s pipelines has been developing continuously, there is a small gap with the world’s top powers, so China should continue to improve the innovation of technology, and more quickly let China’s oil and gas pipelines into the ranks of the world’s top.
5. The basic application of horizontal directional drilling in oil pipelines
- (1) The first thing is to analyze the directional hole drilling to ensure that the drilling process can not appear the situation of drilling offset, to ensure the accuracy of drilling, so as not to affect the progress of the whole oil pipeline arrangement.
- (2) In the process of construction, reaming technology is an integral part of it, because the entire technical main link needs to be carried out, so when carrying out reaming, pay extra attention to details, so that construction can be carried out well. The choice of drill bit should also be operated in accordance with the required specifications to ensure the accuracy of the drill bit.
- (3) Pipeline backstopping is also an operation that occurs in actual construction, and it is based on horizontal directional drilling. This technique can well prevent the wall from being affected to some extent by the long exposure time of the borehole. In the process of back-towing, the borehole is allowed to reach the required cleanliness while also making the wall smoother, which will allow the whole project to proceed smoothly and also contribute to the safety and security of the construction personnel.
6. Horizontal directional drilling in oil pipeline projects need to pay attention to the problems
To explore the problems displayed above, first of all, the relevant construction personnel can choose the following ways: the same hole laying can be used to advance, which is mainly based on the actual operation related to the oil main and optical cable casing, and it can make the effect of back-dragging laying be improved in the actual construction. For the general construction method, the use of the same hole laying not only can save costs and can shorten the construction period, but in the expansion diameter and crossing distance is easy to be limited. Moreover, the winding between the oil main and the fiber optic cable casing can also increase the dragging back resistance and even make the cable break. Therefore, when operating in this way, a comprehensive survey of the construction area’s geomorphology should be done and a precise plan should be developed to carry out the construction. In addition to laying in the same hole, the construction can also be carried out in the way of laying separately. This way focus on the construction effect of the oil main and optical cable pipeline interval, so as to reduce the resistance of the oil main back drag, so that the construction is more secure. In the actual process of construction, the construction metal materials are also particularly important, because the construction metal materials determine the quality of the entire project. In the selection of pipeline materials, let the relevant professionals make purchases to ensure coordination with the fiber optic cable materials, while also ensuring that the materials can properly carry out propulsion operations in the actual construction, and to determine the construction metal materials while also carrying out cost-effective work, so that the project can achieve both cost savings while ensuring project quality. In the time of pipe back dragging, there are corresponding solutions to the problem of back dragging resistance. In general, the direct drag back to the silicon core pipe and drag back to the steel pipe, will certainly be too small diameter of the pipe to lead to the relative tension bad situation. Therefore, it is very important to ensure the smooth operation of the work and to achieve the best results. Currently, the way to reduce the drag resistance is usually by forming a hole. Because this step is very important, the relevant construction personnel must follow the operation standards and use scientific and reasonable operation methods to assist the operation, so that the pipe dragging can reach the expected situation, and then the whole pipeline project can be carried out smoothly and improve the quality of the project.
7. Horizontal directional drilling construction process steps
- (1) Measure and place the line. ① Marking pile: mark the starting and ending position of the required crossing according to the designed standard. ②Boundary pile: At the time of construction, the boundary lines on both sides of the temporary occupation area need to be laid out and marked, with 50m as the unit for interval. The boundary between the axial pile and the temporary occupation should also be set up with a 100m marker, which can be marked with ropes, etc., so that it is staggered from the gray and white line to complete the laying of the pipeline line. After the completion of the placement, the obstacles should be removed and then the data should be recorded.
- (2) Site selection and layout of pipelines. After determining the rig site and pipe-laying site, the actual situation should be analyzed before determining the entry point to ensure that the rig can proceed smoothly. The pipe-laying site is often narrow and long, usually requiring about 80m across the pipe-laying site, and there are certain requirements for width, so do not choose a straight line as long as you can choose a bend.
- (3) Pipeline welding. Before pipe welding, make sure that there is no excessive foreign matter in the pipe mouth, welding to each group of good control of the welding time, to prevent the need to clean the pipe mouth again because of the excessive time. When using the pipe cleaner, choose a soft substance so that it can fully contact the pipe wall to a near-perfect degree. Also, it is important to fight when welding is performed.
- (4) Pre-drilling inspection. Before drilling, the welding and anticorrosive aspects are inspected to ensure that the subsequent works can be carried out properly, thus improving the quality of the whole pipeline project.
- (5) Installation of drilling rig. When installing the drilling rig, ensure that the location of the rig is in the best position, and then carry out the inspection of the whole system to ensure that there is no instability in the process of rig operation to affect the process.
- (6) Drilling rig test drilling. After the rig is installed and the system is commissioned, test drilling of the rig is carried out to ensure its stability. At this time, professional technicians should accept the data, the test drilling depth is generally 40m, and the data parameters will be counted to make sure the data is stable before drilling.
- (7) Drill pilot holes. When drilling the pilot hole, test it to ensure that the traversing curve has reached the technical standard, and once the problem occurs, it should be solved in time. Since the pilot hole will directly affect the final hole formation, the operation should be carried out strictly in accordance with the marked track that has been planned. Also do a good job of data recording so that the drilling rig can proceed precisely. Through the data to do a good job of adjusting each detail, so that the guide hole is carried out to optimize.
- (8) Clear the hole. After the reaming is completed, the hole should be cleared. The selection and parameters of mud should be well studied, and the operator should keep a high tension at all times to record the data and parameters to ensure the quality and ensure that the actual construction can be carried out normally. (9) When the pipe is towed back, the preparatory work is done well in advance and the sending trench is cleaned up. Prepare enough materials such as patching and professional equipment when back-towing. In order to avoid collapse and damage to the integrity of the wall, two cranes can be used at the same time. After the pipe is back-dragged, the water is drained and backfilled in time.
In conclusion, the country’s economic development is getting faster and faster, and the pipeline projects are increasing. Horizontal directional drilling, as an advanced technology in recent years, has allowed China to make significant improvements in oil pipeline technology, but this technology still needs to be slowly improved in practice, so that China’s oil pipeline engineering technology can be qualitatively improved and the transportation efficiency of pipelines can be improved.
Source: China Oil Pipelines Manufacturer – Yaang Pipe Industry Co., Limited (www.ugsteelmill.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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