Optical cable and oil and gas pipeline laying application practice Wu Ying (China Petroleum Pipeline Construction Project Manager, Beijing 100101) Wu Xiying. Application practice of laying optical cables and oil and gas pipelines in the same ditch. Oil and gas storage and transportation, 2011, 30 (7): 547-optical fiber communication was introduced into pipeline communication to meet the high reliability of oil and gas pipeline production and operation and the communication needs of broadband applications. Describes the technical position of the optical cable in the trench, design drawings and construction steps, silicon core tube protection and other technical issues; combined with Shanshan-Urumqi Gas Pipeline, West-East Gas Pipeline, Shaanxi-Beijing Second Line Gas Pipeline, Lanzhou-Zhengzhou One The application practices of the Changsha Oil Product Pipeline and the Second West-East Gas Pipeline and other projects summarized the construction methods and improvement measures of the same trench laying facilities for optical cables and oil and gas pipelines, and pointed out the current problems in construction management, organization and construction responsibilities .
The domestic optical cable and the oil and gas pipeline have been laid in the same trench for 15 years of engineering application. During this period, a total of 17574km of optical cable was laid. In the next five years, nearly 40,000km of optical cable will be laid in the same trench as the new oil and gas pipeline to transmit real-time data and Signals such as images and voice.
An oil pipeline from Trieste in Italy to Ingolstadt in Germany was put into production in 1967. A 7-group 4-core cable was laid in the same ditch as the pipeline for monitoring, telemetry and voice communication of the transmission pipeline Signal; in 1986, NKF (now Draka in the Netherlands) laid an optical cable and a cable along the 80km pipeline between Drenthe and Overissel in the Netherlands.
The above case proves the feasibility of laying the optical cable and the pipeline in the same ditch, but the joint design of the Shaanxi-Beijing first-line gas pipeline with the German PLE company denied this attempt on the grounds that the optical cable was not spared when the pipeline failed Difficult, it will lead to the loss of effective communication support during the emergency repair process. In 1993, the Shanshan-Urumqi Gas Transmission Pipeline pioneered the domestic laying of optical cables and pipelines in the same ditch, which was successfully put into production in 1995. So far, the communication method of laying optical cables in the same trench has been approved by the pipeline project. The desert oil and gas pipelines, Kushan crude oil pipelines, and wheelhouse oil and gas pipelines that have been adopted subsequently have adopted this design and construction method without exception.
1 Main technical issues 1.1 The position of the optical cable in the pipe trench According to foreign data and domestic research results, it is appropriate to lay the optical cable at the bottom of the trench. Foreign construction has strict requirements for the depth, bandwidth and project progress of the trench, but domestic Due to various reasons, it is difficult to guarantee these basic conditions. At the same time, pipeline and optical cable construction belong to different construction parties. The pipeline is the main construction, which is susceptible to terrain restrictions. The construction is often not continuous, which results in a continuous deployment of a cable (usually 2km For a set), the number of random truncation increases, which will inevitably increase the optical transmission attenuation. If the optical cable is moved to the top of the pipe, that is, after the trench is down and the backfill of fine soil is completed, the optical cable can be laid to solve the above problem. According to the design specifications, the buried depth of the optical cable should be greater than 1m, and 100mm thick fine soil or sand should be laid on the stone and semi-stone sections at the bottom of the trench and above the optical cable. GB50251-2003 clearly stipulates: the thickness of the covering soil on the top of the pipe is not less than 0.8m, the pipe trench in the rock and gravel area, the bottom of the trench is dug 0.2m deeper than the pipe trench in the soil area, and the deep excavation is cushioned with fine soil or sand and then lowered When backfilling the pipe trench, first backfill it with fine soil to 0.3m above the top of the pipe before it can be backfilled with soil, sand or gravel with a particle size of less than 100mm and compacted. Therefore, in the stone section, 300mm fine soil is still laid above the optical cable, making it basically consistent with the design requirements of the pipeline laying.
Natural landscape oil and gas storage and transportation OIL 1.2 design and construction pipeline design drawings include two types: one is to draw a longitudinal picture per kilometer in proportion, indicating the relative position of the pipeline and the natural ground, and marking the pipeline crossing the road, railway, river , The specific location of ditches or other structures, the buried depth of the pipeline, the resistivity of the soil, the location of the sign of the pipeline, etc .; the second is the general drawing, which illustrates the specific buried position of the pipeline under various typical conditions in the trench, the general wear Protection measures when crossing, design methods for large river crossings or when excavating and crossing tunnels, etc. The optical cable and the pipeline are laid in the same ditch, which is completely subject to the laying route and construction method of the pipeline. Therefore, it can be made clear: first, there is no need to draw a longitudinal design drawing per kilometer for the optical cable, the pipeline construction is in front, and the optical cable construction is in the rear, the construction party can fully grasp the routing information of the optical cable line from the pipeline construction drawing; second, make full use of The general drawing of the pipeline, the protection measures of the pipeline are also the protection measures of the optical cable, and the method of crossing and crossing is also applicable to the optical cable, for example: the pipeline is protected by a concrete sleeve when crossing the road or railway, and the optical cable can be fixed at an appropriate position in the sleeve Crossing with the pipeline at the same time; when the pipeline passes through the tunnel, the optical cable can be fixed on the tunnel wall; when the pipeline is used for water protection by the cutoff wall, the optical cable is protected with the steel sleeve and fixed together with the pipeline. For the connection of each optical cable, it can be moved to the outside of the pipe trench and the method of direct buried optical cable connection is used.
Construction steps: trench down the pipeline and backfill with fine soil-level out the optical cable trench flush with the top of the pipe on the laid fine soil-lay the optical cable and cover the optical cable with the original fine soil-lay a sign with the pipeline and cable information marked with a pipeline Backfill of the original soil. Mark the routing information of the optical cable on the sign of the pipeline, and add additional optical fiber marking piles at the crossing and turning points. In villages and densely populated areas, implement the requirements for the design of the long-distance optical cable design code; bury the electronic sign at the junction box and run Maintenance personnel can accurately find the buried position of the joint box by means of electronic sign detection.
Optical fiber communication has greatly improved the transmission capacity and transmission quality. Laying optical cables in the same trench eliminates the work of route survey, land acquisition, excavation and laying of trenches for telecommunications operators when laying optical cables. The construction cost per kilometer is only for non-common trench laying The cost of the method is 1/10. 1.3 Silicon core tube protection In 2000, Lancheng-Yu pipeline optical cable design adopted the laying method of silicon core tube protective optical cable. The silicon core tube is a high-density polyethylene plastic tube, and the inner wall is evenly coated with a silicon layer with a thickness of less than 1 mm to increase the hardness and smoothness of the inner wall of the plastic tube. During construction, first lay the silicon core tube with the pipeline in the same trench, and reserve hand holes and manholes per kilometer. Then, use a 12Pa cable blower at the hand holes and manholes to blow at both sides at a normal speed of 5070m / min. The optical cable can blow 1.5km at a time under normal circumstances. The American company Enran used this method to lay a 250km optical cable in the Ratchaburi-WangNo natural gas pipeline trench in Thailand. The advantages of this laying method: first, the silicon core tube can effectively ensure the safety of the optical cable in the trench and extend its service life; second, the silicon core tube is laid first with the pipeline, and the silicon core tube has a special connector that can be cut off at will. Connection, which greatly facilitates the construction; third, the direct buried optical cable is armored cable, and the pipeline optical cable can be selected after the silicon core tube is used. The pipeline optical cable has a layer of wrinkled steel tape less than the armored optical cable, which can save 1 / 3. Purchase cost; Fourth, multiple silicon core tubes can be laid at one time as reserved resources for future routes. Lanchengyu Pipeline has designed three silicon core pipes with the pipeline.
2 Construction Practice 2.1 The West-East Gas Pipeline Project In 2002, the West-East Gas Pipeline Project was constructed using a silicon core tube to protect the optical cable. The silicon core tube was laid along with the pipeline and completed in 2003.
Two years after the pipeline was completed and put into production, the optical cable was blown into the pre-buried silicon core tube. The silicon core tube and the optical cable were constructed in two phases.
2.1.1 Problems in construction The construction efficiency is low. There are many construction steps for optical fiber blowing and release, and due to the impact of the quality of the early silicon core pipe laying facilities, some pre-set holes (hands) have serious restrictions on the construction of optical cables. When it encounters terrain effects and artificial obstructions, it cannot be handled flexibly. , Many people (hands) hole construction points become idle points and "stuck neck" points. According to the location of the human (hand) hole on the drawing, it is difficult to measure the spacing on the site. At the same time, during the pipeline construction process, it is often affected by factors such as land acquisition, terrain difficulty, villagers ’obstruction of work, and the timely arrival of the pipe materials. Continuous welding, ditching and backfilling are not possible, which affects the measurement work of the optical cable. It cannot accurately measure and provide data to the optical cable manufacturers in time, which affects the normal production of the optical cable distribution plate.
The construction is difficult. According to the specifications and design requirements, the manhole structure is generally a semi-underground structure made of mixed materials such as brick, sand, and reinforced concrete, with an average of one per kilometer. The construction is more difficult because the construction of human (hand) holes is implemented by civil construction and national key large-scale engineering standards, the procedures are complicated, and the requirements for testing procedures and quality inspection materials are complete. When on-site construction, construction work points are scattered and human (hand) ) The concrete construction of the hole requires a maintenance cycle, which makes it impossible to provide various test blocks and other testing procedures on time, so that the human (hand) hole cannot be backfilled in time after the completion of the construction, and the optical cable cannot be blown out in time, causing the construction of the human (hand) hole and the optical cable. Seriously lagging behind pipeline construction. In the arid and water-scarce areas in the west, construction is more difficult. ) Blocking phenomenon. After the pipeline was ditched and backfilled, the landform was basically restored, and local villagers immediately planted crops, but the fiber optic cable construction needed to be re-entered. Compensation for permanent land acquisition and temporary land occupation for pipeline construction does not include compensation for re-entry of fiber optic cable construction. At the same time, some problems are left more or less in the early stage of pipeline construction, resulting in extremely serious obstruction of villagers.
2.1.2 Problems in operation and maintenance The silicon core tube (including optical cable) is buried in insufficient depth in some areas, and it has been repeatedly damaged by illegal construction by third parties. In some areas, the silicon core tube floats on the ground during the rainy season, which is not conducive to normal signal transmission and operation and maintenance.
The one-time (manual) hole building has a large one-time investment and the reuse rate is not high. Once the optical cable is dug by the third-party construction, the breakpoint will not happen to be in the reserved man (hand) hole position, and it cannot be avoided to excavate again, but it is easily damaged by the third-party construction and needs to be drained regularly, which increases the operation and maintenance. Workload. ) In densely populated and economically developed areas, it is not enough to rely on the marking piles of the pipeline for the marking of the optical cable path. Frequent earthmoving on these routes and the frequent loss and movement of the marking piles have caused many difficulties for operation and maintenance and maintenance. Therefore, it is necessary to increase the density of the fiber optic cable marking piles, and to increase the fiber optic cable warning signs at the positions where they are crossed.
2.2 Shaanxi-Beijing Second Line Gas Transmission Project During the construction of the Shaanxi-Beijing Second Line in 2003, in order to reduce the difficulty of coordinating the laying of pipelines and communication optical cables in the same ditch and speed up the construction of the pipeline, the optical cable operation was handed over to the pipeline construction party for construction Due to the mechanized construction of the pipeline, manual deployment of optical cables requires additional manpower, and the construction personnel have little knowledge of optical cables. The cable sheath is easy to be scratched during laying, which reduces the waterproof and insulating performance of the optical cable; secondly, the splice of each cable is required The communication professional mechanic completed it, and the communication construction party only guaranteed its own joint index, and was not responsible for the entire construction performance index of the optical cable. Therefore, the two construction parties pushed and criticized each other for the construction quality of the optical cable, which was not conducive to the owner's accountability.
2.3 Lan Zhengchang Refined Oil Pipeline Project made the following improvements when designing the pipeline in 2006: First, mark the position of the optical cable on the pipeline construction drawings, so that the pipeline builder can enhance the awareness of the mutual cooperation of optical cable embedding. The marking pile of the optical cable is set separately and increased to one every 250m; the second is to increase the buried depth detection process of the optical cable laying during the local construction acceptance stage, and the problems existing in the optical cable laying facilities are rectified in time; the third is to clarify the silicon core tube and oil pipeline in different sections The procedure and responsibility interface of the road crossing construction, that is, after the first fine soil backfill is completed, the pipeline builder notifies the communication builder in writing. The communication builder must arrive at the site for process acceptance within 24 hours after receiving the notification. Silicon core pipe laying facility worker. The acceptance standard is: the backfilling of fine soil in the pipe trench to a height of 300mm above the top of the pipe, the fine soil is even and flat, and the condition of laying silicon core tubes for more than 500m continuously (optical cable must have more than 1 000m continuous). The communication constructor digs a trench and lays a silicon core tube (the trench depth is 400mm, which is 100mm lower than the top of the pipeline) on the backfilled fine soil. After the cable trench is backfilled, the pipeline builder is notified in writing, and the pipeline builder lays a warning tape and a secondary backfill. Filling (large backfilling) Fourth, it is recommended that when traversing small ditches and ponds, if the pipeline and the optical cable (silicon core tube) cannot be laid simultaneously, small directional drilling can be used to implement the separate crossing of the optical cable; fifth, the silicon core tube and optical cable are constructed at the same time. Try to avoid the construction of the second station and the second compensation.
2.4 The Second West-East Gas Pipeline Project The second West-East Gas Pipeline project will be constructed and put into operation in two phases, the west and east sections. The west section is located in the west, sparsely populated, third-party damage is very small, the optical cable can be protected without a silicon core tube, and it is placed at the bottom of the pipeline and the top of the pipeline is not much different, so the design requires the buried depth of the directly buried armored optical cable in the frozen soil layer The following is enough; the eastern section passes through economically developed areas and the water network is dense, so the silicon core tube is used to protect the optical cable, while relying on the experience of laying the same ditch in the West-East Gas Pipeline, the management mode of the Lanzheng Chang pipeline is adopted, and the hand is cancelled. Hole setting. Engineering practice has proved that the above method is reasonable and effective, which can greatly save engineering investment. Only by eliminating the hand hole statistics, the investment is saved by about 2,000 yuan / km. In addition, the construction of composite manholes instead of brick manholes The investment calculation can also reduce the engineering investment, but whether it is beneficial to operation and maintenance still needs engineering practice verification.
In summary, it is technically feasible to lay the optical fiber cable and the oil and gas pipeline in the same ditch, and is gradually improving through application practice. At present, the main problems are essentially the problems of construction management, organization and construction responsibilities. The effective coordination of the two construction parties of pipeline and communication, so that they can perform their duties and work together to ensure the quality of the project, is the basic guarantee for the project contractor to submit qualified projects to the owner and the operator.
The communication major of the Oil and Gas Pipeline Workers College is currently mainly engaged in the management of the communication engineering of natural gas and oil pipeline construction projects.
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