Pipeline filling method and system for cement paste filling without cleaning

Abstract

The present invention provides a method and system for filling a pipeline filled with cement paste without cleaning, wherein the pipeline includes a ground filling main pipe and a downhole filling main pipe, and a first stop valve is provided between the ground filling main pipe and the downhole filling main pipe, and a second stop valve is provided at the end of the downhole filling main pipe; the filling method includes: configuring cement paste and non-cement paste; using cement paste to sequentially transport to a to-be-filled area through the ground filling main pipe and the downhole filling main pipe, and when filling is completed, starting to transport non-cement paste and ensuring that the downhole filling main pipe is entirely filled with non-cement paste; closing the second stop valve and the first stop valve in sequence, and then draining and cleaning the ground filling main pipe; when filling next time, first pumping new non-cement paste, and then pumping cement paste after the old non-cement paste is completely discharged. The present invention does not require cleaning of the pipeline and can solve the problem of the impact of the old non-cement paste accumulated in the pipeline on the pumping safety and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of filling engineering, and in particular to a pipeline non-cleaning filling method and a filling system for filling with cement paste. Background Art

[0002] The proportion of the paste for coal mine gangue paste filling is generally composed of coal gangue + cement + fly ash + water. The coal mine paste filling system generally builds the filling station on the ground. The entire filling pipeline system has a one-time conveying length of 1000m to 6000m and the pipeline direction is basically a negative slope. In order to ensure the safety of pipeline transportation, it is generally required that the filling material should not be separated or leak water within the pumpable time, and the slump should meet the requirements. It is required to ensure that the pipeline paste is full in the early stage of filling to avoid water hammer damage to the pipeline. At the same time, it is required to push out the residual paste in the pipeline at the end of filling and clean the pipeline to facilitate the next filling cycle. Therefore, each filling cycle wastes about 100m of water. 3 ~500m 3 , 30m of filling material wasted 3 ~200m 3 Each production cycle has an ineffective working time of 3 to 5 hours. Replacing the filling with a non-cementing paste is an effective method, but the significant performance differences between non-cementing and cementing pastes result in significant pressure fluctuations in the filling pipeline. Therefore, the use of non-cementing pastes places higher demands on the process parameters for the next filling cycle. Without adaptive improvements, it will be difficult to ensure pipeline safety, thereby reducing its service life.

[0003] To this end, the present invention proposes a pipeline filling method and filling system for cement paste filling without cleaning to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for filling a pipeline with adhesive paste without cleaning. By pumping non-adhesive paste at the end of filling, and first pumping new non-adhesive paste and then pumping adhesive paste during the next filling, the problem of the impact of old non-adhesive paste accumulated in the pipeline on pumping safety and stability is solved while ensuring that the pipeline is not cleaned.

[0005] To achieve the above-mentioned object, the present invention provides a method for filling a pipeline with cement paste without cleaning, wherein the pipeline includes a surface filling trunk pipe and a downhole filling trunk pipe, a first stop valve is provided between the surface filling trunk pipe and the downhole filling trunk pipe, and a second stop valve is provided at the end of the downhole filling trunk pipe; the filling method comprises:

[0006] S1. Prepare cementing paste and non-cementing paste;

[0007] S2. The cement paste is sequentially transported through the surface filling main pipe and the downhole filling main pipe to the area to be filled. When the filling is completed, the non-cement paste is transported and the downhole filling main pipe is ensured to be entirely filled with non-cement paste.

[0008] S3. Sequentially close the second stop valve and the first stop valve, then exclude and clean the ground filling main pipe;

[0009] S4. When the next filling is to be carried out, new non-cemented paste is pumped in first. After the old non-cemented paste is completely discharged to the area to be filled, the cemented paste is pumped in again to achieve cyclic filling without cleaning.

[0010] Furthermore, the cementitious paste includes coal gangue or aeolian sand, fly ash, silicate cement and water; the non-cementitious paste includes coal gangue or aeolian sand, fly ash, suspending agent and water.

[0011] Furthermore, the suspending agent includes one or more of polyacrylamide, polyvinyl alcohol and sodium lauryl sulfate.

[0012] Furthermore, the mass concentration of the cementitious paste is 70% to 82%, and the mass concentration of the non-cementitious paste is 75% to 80%; the particle size of the gangue aggregate is ≤10mm, of which the gangue powder with a particle size of less than 0.08mm accounts for ≥30%, and the amount of the fly ash is ≤100kg / m 3 .

[0013] Furthermore, the amount of the suspending agent is 5 to 10 kg / m 3 The non-cementitious paste has a pumpable time of not less than 24 hours and a slump of 240 mm to 260 mm.

[0014] Furthermore, in step S4, the pumping and filling includes:

[0015] S41 before restarting the pumping, first start the downhole filling main pipe hydraulic spiral stirrer, the non-cemented paste is stirred and dispersed;

[0016] S42. Prepare the non-cemented paste again, and the slurry volume is greater than or equal to the volume of the trunk pipeline;

[0017] S43. Open the first stop valve and the second stop valve, and make the second stop valve open to 1 / 2, and start pumping the slurry; the pumping capacity reaches 50m 3 / h, fully open the second stop valve;

[0018] S44. After all the old non-cemented paste is discharged and the pressure at each pressure monitoring point of the pipeline is normal, start preparing the cemented paste and carry out the normal filling cycle.

[0019] Further, in step S43, the first 3m of pumping 3 The pumping capacity is 10~30m 3 / h, pulping reaches 20m 3 When the pumping capacity is increased to 120-150m 3 .

[0020] The present invention also provides a filling system for the above-mentioned cement paste filling method without cleaning the pipeline, comprising a surface slurrying system and a downhole filling and conveying system; the surface slurrying system comprises a slurrying module and a surface filling trunk pipe, and the downhole filling and conveying system comprises a downhole filling trunk pipe connected to the surface filling trunk pipe and a hydraulic spiral agitator provided on the downhole filling trunk pipe;

[0021] A first stop valve is provided between the surface filling trunk pipe and the downhole filling trunk pipe, and the end of the downhole filling trunk pipe is connected to the filling area and is provided with a second stop valve.

[0022] Furthermore, a hydraulic spiral agitator is provided on the downhole filling trunk pipe at intervals of 1000 m.

[0023] Furthermore, the pulping module includes a solid material feeding unit, a liquid material feeding unit, a mixing unit, a filling pump and a switching valve; the switching valve is connected to the first stop valve; the switching valve is also connected to a sewage tank for cleaning and treating the ground filling trunk pipe;

[0024] The liquid material feeding unit comprises a suspension agent adding tank, a filling pump, a flow meter solenoid valve and a water weighing hopper which are connected in sequence; the water weighing hopper is connected to the mixing unit.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention provides a method and system for filling a pipeline without cleaning by filling it with a cement paste. After filling is completed, a non-cement paste is filled in the underground filling trunk pipe. The non-cement paste is used to flow, so that the paste will not be blocked by cement in the underground filling trunk pipe, so there is no need to consume a large amount of clean water to clean the pipeline. At the same time, the paste can also play a filling role in the filling area, so that the non-cement paste is discharged into the filling area at the beginning of the circulation filling, reducing paste waste, reducing the amount of cement, and saving costs. Moreover, a new non-cement paste is used for transition at the beginning of the filling, reducing the pipeline fluctuation problem caused by excessive slurry differences. At the same time, it is also convenient to form a stable transition in the filling area, improving the stability of the filling interface.

[0027] The present invention reduces the difference between the two pastes by designing the aggregate types of the cementitious paste and the non-cementitious paste, which helps to improve the transportation transition stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a structural schematic diagram of the pipeline non-cleaning filling system of the cement paste provided by the present invention.

[0030] Reference numerals:

[0031] 10-ground pulping system; 11-solid material feeding unit; 12-liquid material feeding unit; 121-suspending agent adding tank; 122-filling pump; 123-flow meter solenoid valve; 124-water weighing hopper; 13-mixing unit; 14-filling pump; 15-switching valve; 16-first stop valve; 17-ground filling trunk pipe; 18-sewage tank; 20-underground filling and conveying system; 21-underground filling trunk pipe; 22-hydraulic spiral agitator; 23-second stop valve; 24-filling area. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] See also Figure 1As shown, the present invention first provides a pipeline non-cleaning filling system for cement paste, including a surface slurrying system 10 and a downhole filling and conveying system 20; the surface slurrying system 10 includes a slurrying module and a surface filling main pipe 17, and the downhole filling and conveying system 20 includes a downhole filling main pipe 21 connected to the surface filling main pipe 17 and a hydraulic screw agitator 22 arranged on the downhole filling main pipe 21. A first stop valve 16 is provided between the surface filling main pipe 17 and the downhole filling main pipe 21. The end of the downhole filling main pipe 21 is connected to the filling area 24 and is provided with a second stop valve 23. With this arrangement, the paste is prepared on the ground and then gradually conveyed to the filling area 24 through the surface filling main pipe 17 and the downhole filling main pipe 21. The first stop valve 16 and the second stop valve 23 are used to control the opening and closing of the paste conveying, so as to facilitate the control of the conveying of different pastes and the conveying amount. The hydraulic spiral stirrer 22 facilitates stirring and dispersing the non-cemented paste in the downhole filling trunk pipe 21 to prevent it from settling and affecting the transportation in the pipeline and the filling performance after entering the filling area 24.

[0034] Specifically, hydraulic spiral agitators 22 are installed every 500-1000 meters along the downhole filling mainline 21. These agitators are hydraulically driven, and a centralized surface control and monitoring system facilitates comprehensive monitoring of downhole operations. Downhole filling mainline 21 typically ranges from 1000 to 6000 meters in length and has a diameter of 100-500 mm.

[0035] The pulping module includes a solid material feed unit 11, a liquid material feed unit 12, a mixing unit 13, a filling pump 14, and a switching valve 15. The switching valve 15 is connected to a first shut-off valve 16. The switching valve 15 is also connected to a sewage tank 18 for cleaning and treating the surface filling main line 17. The solid material feed unit 11 is used to add aggregates such as coal gangue, aeolian sand, fly ash, and Portland cement. The switching valve 15 switches the line between flowing underground or to the sewage tank 18, facilitating filling pumping and cleaning of the surface pulping system 10.

[0036] The liquid material feeding unit 12 includes a suspending agent addition tank 121, a filling pump 122, a flowmeter solenoid valve 123, and a water weighing hopper 124, which are connected in sequence. The water weighing hopper 124 is connected to the mixing unit 13. The suspending agent is added to the water weighing hopper 124 of the ground paste preparation system through a pumped pipeline and measured by a flowmeter. The metering signal is connected to the ground filling centralized monitoring system.

[0037] Furthermore, the present invention provides a method for filling a pipe with a cement paste without cleaning, comprising the following steps:

[0038] S1. Prepare cementing paste and non-cementing paste;

[0039] S2. Use cementing paste to transport it to the area to be filled 24 through the ground filling trunk pipe 17 and the underground filling trunk pipe 21 in sequence. When the filling is completed, start transporting non-cementing paste and ensure that the underground filling trunk pipe 21 is filled with non-cementing paste. Generally, before the first filling, the volume of the paste trunk pipe is calculated based on the inner diameter and length of the filling pipe, so as to facilitate the control of the pumping volume of the non-cementing paste.

[0040] S3. Close the second stop valve 23 and the first stop valve 16 in sequence, and then drain and clean the ground filling main pipe 17; clean the ground filling main pipe 17 to reserve a certain pipeline space for the next circulation pumping, thereby improving the stability of the paste pumping and preventing the old non-cemented paste from causing large fluctuations when the pumping is started directly, affecting the stability of the pipeline.

[0041] S4. When the next filling is to be carried out, new non-cementing paste is pumped in first. After all the old non-cementing paste is discharged to the area to be filled 24, the cementing paste is pumped in again, thus realizing the cyclic filling without cleaning.

[0042] In this way, after the filling is completed, the non-cementing paste is filled in the underground filling trunk pipe 21. The non-cementing flowable characteristics of the paste are used to prevent the paste from being blocked in the underground filling trunk pipe 21, so there is no need to consume a large amount of clean water to clean the pipeline. At the same time, the paste can also play a filling role in the filling area 14, so that the non-cementing paste is first discharged into the filling area 24 at the beginning of the circulation filling, reducing the waste of the paste and the amount of cement, thus saving costs. Moreover, the old non-cementing paste forms the initial base layer in the filling area 24, the new non-cementing paste forms the transition layer, and finally the cementing paste forms the high-strength support layer. The filling process formed in this way can not only ensure the strength of the filling area 24, but also avoid pipeline cleaning, reduce resource waste, save filling time, and realize continuous and uninterrupted filling of multiple filling areas, thereby improving filling capacity. In addition, since the dispersion uniformity and stability of the old non-cementitious paste will change during the circulation waiting process, in order to prevent it from affecting the stability of the pipeline flow, the present invention first pumps the same non-cementitious paste at the beginning of the circulation to achieve the transition of cementitious paste pumping, thereby reducing the pipeline fluctuation problem caused by excessive slurry differences.

[0043] In particular, in step S4, pumping and filling includes:

[0044] S41 before restarting the pumping, first start the downhole filling main pipe on the hydraulic spiral stirrer 22, the non-cemented paste is stirred and dispersed;

[0045] S42. Prepare the non-cement paste again, and the volume of the paste should be greater than or equal to the volume of the trunk pipeline, for example, equal to or 1-5m larger. 3The purpose is to completely discharge the old non-cemented paste to facilitate the formation of a stable pumping transition.

[0046] S43. Open the first stop valve 16 and the second stop valve 23, and make the opening degree of the second stop valve 23 1 / 2, and start pumping the slurry; 3m before pumping 3 The pumping capacity is 10~30m 3 / h, pulping reaches 20m 3 When the pumping capacity is increased to 120-150m 3 / h; when the pumping capacity reaches 50m 3 / h, fully open the second stop valve 23; in this way, by controlling the opening degree of the second stop valve 23 during the pumping process, the pumping stability is regulated.

[0047] S44. After all the old non-cemented paste is discharged and the pressure at each pressure monitoring point of the pipeline is normal, start preparing the cemented paste and carry out the normal filling cycle.

[0048] The cementitious paste of the present invention uses the same aggregates as the non-cementitious paste: gangue or aeolian sand, and fly ash. Specifically, the cementitious paste of the present invention preferably comprises gangue or aeolian sand, fly ash, Portland cement, and water. The cementitious paste has a mass concentration of 70% to 82%, the gangue aggregate particle size is generally less than or equal to 10 mm, and the mass ratio of the components is approximately 6:1:1:2. The cementitious paste can be pumped for 2 to 4 hours after standing.

[0049] The non-cemented paste is composed of coal gangue or aeolian sand, fly ash, suspending agent and water. The mass concentration of the non-cemented paste is 75% to 80%; the particle size of the coal gangue aggregate is generally less than or equal to 10mm, of which the proportion of gangue powder with a particle size of less than 0.08mm is not less than 30%, and the amount of fly ash is not more than 100kg / m 3 , the dosage of suspension agent is 5~10kg / m 3 The non-cemented paste should be pumpable for at least 24 hours and have a slump of 240mm to 260mm. Suspending agents include one or more of polyacrylamide, polyvinyl alcohol, and sodium lauryl sulfate. Suspending agents slow the settling rate of the non-cemented paste aggregate, ensuring safe delivery of the paste after the system restarts after the designed settling time.

[0050] The present invention reduces the difference between the two pastes by designing the same type of aggregate for the cementitious paste and the non-cementitious paste, which helps to improve the stability of the conveying transition; moreover, after entering the filling area 24, the transition layer formed by the non-cementitious paste facilitates the formation of a high-strength support layer with the cementitious paste to achieve a high-strength interface bonding, thereby improving the filling stability.

[0051] After the system and process of the present invention are put into operation, the filling time of each time is effectively shortened by 3 hours, the filling air, water, electricity and material inputs are reduced, continuous and uninterrupted filling of multiple filling areas can be achieved, and the filling capacity is improved.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for filling a pipe with a cement paste without cleaning, characterized in that: The pipeline includes a ground filling trunk pipe and a downhole filling trunk pipe, and a first stop valve is provided between the ground filling trunk pipe and the downhole filling trunk pipe, and a second stop valve is provided at the end of the downhole filling trunk pipe; the filling method includes: S1. Prepare cementing paste and non-cementing paste; S2. The cement paste is sequentially transported through the surface filling main pipe and the downhole filling main pipe to the area to be filled. When the filling is completed, the non-cement paste is transported and the downhole filling main pipe is ensured to be entirely filled with non-cement paste. S3. Sequentially close the second stop valve and the first stop valve, then exclude and clean the ground filling main pipe; S4. When the next filling is to be carried out, the new non-cemented paste is pumped in first. After the old non-cemented paste is completely discharged into the area to be filled, the cemented paste is pumped in again, thus achieving a cycle filling without cleaning. Specifically include: S41. Before resuming pumping, start the hydraulic spiral agitator on the downhole filling main pipe to stir and disperse the old non-cemented paste; S42. Prepare a new non-cemented paste again, and the slurry volume must be greater than or equal to the volume of the trunk pipeline; S43. Open the first stop valve and the second stop valve, and make the second stop valve open to 1 / 2, and start pumping the slurry; the pumping capacity reaches 50m 3 / h, fully open the second stop valve; S44. After all the old non-cemented paste is discharged and the pressure at each pressure monitoring point of the pipeline is normal, start preparing the cemented paste and perform a normal filling cycle.

2. The method for filling a pipe with cement paste without cleaning according to claim 1, characterized in that: The cementitious paste comprises coal gangue, fly ash, silicate cement and water; the non-cementitious paste comprises coal gangue, fly ash, suspending agent and water; Alternatively, the cementitious paste comprises aeolian sand, fly ash, silicate cement and water; and the non-cementitious paste comprises aeolian sand, fly ash, suspending agent and water.

3. The method for filling a pipe with cement paste without cleaning according to claim 2, characterized in that: The suspending agent includes one or more of polyacrylamide, polyvinyl alcohol and sodium lauryl sulfate.

4. The method for filling a pipe with cement paste without cleaning according to claim 2, characterized in that: The mass concentration of the cementitious paste is 70% to 82%, and the mass concentration of the non-cementitious paste is 75% to 80%; The particle size of the coal gangue aggregate of the non-cementitious paste is ≤10mm, of which the proportion of gangue powder with a particle size less than 0.08mm is ≥30%, and the amount of fly ash used in the non-cementitious paste is ≤100kg / m 3 .

5. The method for filling a pipe with cement paste without cleaning according to claim 2, characterized in that: The dosage of the suspending agent is 5-10 kg / m 3 The non-cementitious paste has a pumpable time of not less than 24 hours and a slump of 240 mm to 260 mm.

6. The method for filling a pipe with cement paste without cleaning according to claim 1, characterized in that: In step S43, the first 3m of pumping 3 The pumping capacity is 10~30m 3 / h, pulping reaches 20m 3 When the pumping capacity is increased to 120~150m 3 .

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