Installation method of inclined directional long drill hole grouting casing pipe under unconsolidated formation

Abstract

The invention discloses a method for installing a grouting sleeve for an inclined directional long drill hole under a loose formation, which adopts the measures of advanced connection of a plurality of grouting sleeves, floating descending of the sleeves, suspension of a plurality of cranes, back planing and descending of an excavator and the like, and effectively solves the problems of drill jamming, centering, hole collapse and deviation in the prior art. According to the long drill hole floating type descending method, it is guaranteed that the resistance of the grouting casing pipe is small in the descending process, and the descending stability and the construction speed of the casing pipe are remarkably improved. Besides, through high-pressure grouting consolidation and secondary grouting consolidation of the built-in wear-resistant super-long oil casing, the stability and durability of the whole structure are enhanced, the construction efficiency and safety are effectively improved, and the construction method is suitable for large-scale industrial use and popularization.

Description

Technical Field

[0001] The invention relates to the field of grouting transformation, and in particular to an installation method of an inclined directional long-drilled grouting casing under a loose layer. Background Art

[0002] As coal resources in eastern mines in my country become increasingly scarce, the proportion of western mining areas in my country's coal production capacity is increasing. Coal seams in western mining areas are shallowly buried and water resources are scarce. Mine water is mainly roof aquifer water. Water must be drained before mining. In order to achieve water-saving coal mining, it is necessary to grout the roof water of the coal seam. Due to the particularity of hydrogeological conditions, the grouting interception layer in some western mining areas is the bedrock weathering zone aquifer, and the upper strata of the bedrock weathering zone are loose layers. The specific method of grouting interception in the bedrock weathering zone is to drill the horizontal section of the inclined flat hole along the layer, and carry out local grouting transformation of the bedrock weathering zone. During the implementation, the grouting guide hole needs to first pass through the loose layer at a small angle to enter the bedrock weathering zone, and then put in the grouting casing. Due to the small angle of the opening section of the inclined flat hole, the length of the grouting casing is much longer than the length of the vertical hole, and the length reaches more than 300m under some formation conditions.

[0003] A loose layer refers to a stratum that is mainly composed of uncemented or weakly cemented granular materials. The geological conditions of the loose layer have the following characteristics: (1) The loose layer is composed of loose sand, silt or clay particles. The bonding force between the particles is weak and they are easily moved or deformed under the action of external forces. (2) The loose layer usually has a high porosity, and water can easily move in it, which also leads to poor stability of the stratum. (3) Due to the insufficient bonding force between the loose particles, the hole wall is prone to collapse during the drilling or casing lowering process, resulting in a hole collapse phenomenon, which increases the difficulty of construction. (4) The loose layer has a low bearing capacity, and foundation settlement or uneven deformation is prone to occur during heavy machinery construction.

[0004] In the prior art, the commonly used method for installing grouting casing in loose layers is the forward push method of the drilling rig. This method directly uses wear-resistant petroleum casing and uses the drilling rig to push the casing to a predetermined depth for grouting consolidation. Due to the above characteristics of the loose layer, the prior art usually faces the following problems when installing grouting casing under loose layer geological conditions: (1) The rigidity of the single-layer casing is large. Due to the large depth of the inclined hole, the drilling trajectory in the loose layer will bend to a certain extent, so the loose layer may push the casing. The casing is stuck in the stratum and cannot be lowered, and the casing will be stuck in the borehole. (2) The casing is open-end, and the casing is directly pushed forward. It is easy for the casing to sink to the bottom of the borehole and penetrate into the loose layer and get stuck. (3) When multiple single-tube continuous entry is performed during direct forward push, multiple welding must be performed. One end of the added casing is welded to the casing in the borehole, and the other end is connected to the short section on the drilling rig. It is difficult to align the casing axis during suspended construction. (4) The forward push method is used for multiple welding operations, which takes a long time and easily results in hole collapse during the pipe lowering process. After the hole collapses, the casing cannot be pushed forward normally.

[0005] In summary, the existing drilling rig forward push grouting pipe method has many problems under loose geological conditions, resulting in low construction efficiency and poor construction safety. Summary of the invention

[0006] The purpose of the present invention is to provide a method for installing an inclined directional long borehole grouting casing under a loose layer, so as to solve the problems of low construction efficiency and poor construction safety when installing the grouting casing under the existing loose layer geological conditions.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0008] A method for installing an inclined directional long drilling grouting casing under a loose layer comprises the following steps:

[0009] Step 1, determining the total length of the grouting casing required according to the length of the downward directional drilling hole that has been completed in the loose layer;

[0010] Step 2, multiple short-section grouting sleeves are fixedly connected end to end in sequence until the length reaches the required total length of the grouting sleeve to form a long borehole grouting sleeve;

[0011] Step 3, constructing a sloped soil platform in front of the completed downward directional drilling hole, making the slope of the soil platform consistent with the downward directional drilling hole and making the soil platform and the downward directional drilling hole collinear;

[0012] Step 4, plugging the front end of the long drilling grouting casing;

[0013] Step 5, multiple cranes are arranged along the axial direction of the long borehole grouting casing, and the long borehole grouting casing is suspended by the multiple cranes together so that the long borehole grouting casing does not deform;

[0014] Step 6, using multiple cranes to float the long drilling grouting casing into the borehole until the front end of the long drilling grouting casing is lowered into the bottom of the borehole;

[0015] Step 7, using a drilling rig to lower a drill rod into the long borehole grouting casing to the front end of the long borehole grouting casing, performing hole sweeping on the front end of the long borehole grouting casing, and recovering the drill rod after the hole sweeping is completed;

[0016] Step 8, using a positive circulation grouting method, injecting slurry into the long borehole grouting casing until the slurry fills the annular space between the long borehole grouting casing and the wall of the downward inclined directional borehole and then returns from the ground, then stops grouting and waits for the slurry to solidify to form a consolidation layer;

[0017] Step 9, insert another oil casing of matching specifications into the inner wall of the long borehole grouting casing, and repeat step 8 again after the oil casing reaches the bottom of the downward inclined directional drilling hole to complete the installation of the long borehole grouting casing.

[0018] The present invention also has the following features:

[0019] Further, in step 2, the plurality of short-section grouting sleeves are divided into two groups of equal number, and the two groups of short-section grouting sleeves are respectively connected end to end to form two grouting sleeves, so that the two groups of grouting sleeves can be connected end to end to form a long borehole grouting sleeve;

[0020] In step 4, one end of the first grouting sleeve is used as the front end of the long borehole grouting sleeve to block the front end of the long borehole grouting sleeve;

[0021] In step 5, a plurality of cranes are used to jointly suspend the first grouting sleeve so that the first grouting sleeve does not deform;

[0022] Step 6, using multiple cranes to float the first grouting casing into the downward inclined directional borehole, until most of the first grouting casing enters the borehole, multiple cranes move to the corresponding position of the second grouting casing, lift the second grouting casing and coaxially fix the second grouting casing to the rear end of the previous grouting casing to form a long borehole grouting casing;

[0023] Continue to float down the long borehole grouting casing until the front end of the long borehole grouting casing reaches the bottom of the downward inclined directional borehole.

[0024] Furthermore, in step 6, multiple cranes are used to float the first grouting casing into the downward inclined directional borehole until two-thirds of the first grouting casing enters the downward inclined directional borehole, and then the second grouting casing is coaxially fixedly connected to the rear end of the first grouting casing to form a long borehole grouting casing.

[0025] Furthermore, in step 4, a hemispherical or arc-shaped plug is used to seal the front end of the long borehole grouting casing.

[0026] Further, in step 6, in the process of floatingly pushing the casing into the downward inclined directional drilling hole with the cooperation of multiple cranes, each time the sling lifted by a crane reaches the hole mouth of the downward inclined directional drilling hole, the corresponding sling is untied; when the sling lifted by the last crane reaches the bottom of the hole, the corresponding sling is not untied;

[0027] In step 7, after the hole sweeping is completed, when the slurry liquid level in the long borehole grouting casing is restored to the same level as the slurry liquid level outside the long borehole grouting casing, the sling corresponding to the last crane is untied and the drill rod is recovered.

[0028] Furthermore, in step 6, an excavator is set at the mouth of the downward inclined directional drilling hole. In the process of floatingly pushing the casing into the downward inclined directional drilling hole with the cooperation of multiple cranes, the excavator is used to continuously back-scrape the long drilling grouting casing to assist in pushing the long drilling grouting casing.

[0029] Furthermore, in step 6, before the grouting casing is floated into the downward inclined directional borehole using multiple cranes, a lubricant is injected into the downward inclined directional borehole.

[0030] Furthermore, in step 9, the oil casing adopts API oil casing.

[0031] Compared with the prior art, the present invention has the following technical effects:

[0032] The present invention discloses a method for installing a grouting casing for a long inclined directional borehole in a loose layer, which adopts measures such as advance connection of multiple grouting casings, floating downward movement of casings, suspension by multiple cranes and back-digging and lowering by excavators, thereby effectively solving the problems of drill sticking, centering, hole collapse and deviation existing in the prior art.

[0033] The long-borehole floating descending method proposed by the method of the present invention ensures that the resistance of the grouting casing is small during the lowering process, and significantly improves the casing lowering stability and construction speed. In addition, through high-pressure grouting consolidation and secondary grouting consolidation of the built-in wear-resistant ultra-long petroleum casing, the stability and durability of the overall structure are enhanced, the construction efficiency and safety are effectively improved, and it is suitable for large-scale use and promotion in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1is a schematic diagram of an overall construction device in one embodiment of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of a long borehole grouting casing in one embodiment of the present invention;

[0036] Figure 3 It is a schematic diagram of a long borehole grouting casing floating downward in one embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of grouting consolidation in one embodiment of the present invention;

[0038] Figure 5 The present invention is a schematic diagram of setting a petroleum casing on the inner wall of a long borehole grouting casing in one embodiment of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that, unless otherwise specified, all components in the present invention are components known in the prior art. For example, the grouting sleeve is a known and commonly used grouting sleeve.

[0040] All methods in the present invention, unless otherwise specified, are methods known in the prior art, such as the positive circulation method, which is a known method in the prior art.

[0041] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0042] A method for installing an inclined directional long drilling grouting casing under a loose layer comprises the following steps:

[0043] Step 1, according to the length of the downward directional drilling hole that has been completed in the loose layer, determine the total length of the grouting casing required; the total length of the grouting casing is determined by technical personnel in this field according to actual needs.

[0044] Optionally, the total length of the grouting sleeve is equal to the length of the 10m section of the borehole from the opening to the entry into the weathered bedrock. In addition, those skilled in the art have the ability to further select the total length of the grouting sleeve according to actual needs.

[0045] Step 2, connecting multiple short-section grouting casings end to end in sequence until the length reaches the required total length of the grouting casing to form a long borehole grouting casing;

[0046] It should be noted that the downward inclined directional borehole that has been completed in the loose layer is a bare hole. At this time, the borehole is filled with mud and other slurries. On the one hand, it reduces the time for welding section by section and saves time when the subsequent long borehole grouting casing is lowered. It can be completely lowered before the mud in the borehole solidifies. On the other hand, it reduces the difficulty of centering and reduces the risk of the long borehole grouting casing getting stuck during the lowering process.

[0047] Step 3, build a sloped soil platform in front of the completed borehole mouth, make the slope of the soil platform consistent with the borehole and make the soil platform and the borehole collinear.

[0048] Before drilling, build a sloped soil platform with the slope side of the platform facing the borehole. The slope is consistent with the inclination of the borehole and can be connected in a straight line. Place the front end of the long borehole grouting casing on the slope to facilitate the long borehole grouting casing to go down along the slope.

[0049] Step 4, seal the front end of the long borehole grouting casing; the purpose is to isolate the inside and outside of the long borehole grouting casing, so that a hollow area can be generated inside the long borehole grouting casing, making it easier for the long borehole grouting casing to float, preparing for subsequent steps.

[0050] Step 5, multiple cranes are arranged along the axial direction of the long borehole grouting casing, and the long borehole grouting casing is suspended by the multiple cranes together, so that the long borehole grouting casing does not deform, and it is also beneficial to reduce the friction of the long borehole grouting casing when it is lowered.

[0051] Step 6, use multiple cranes to float the long drilling grouting casing into the borehole until the front end of the long drilling grouting casing is lowered into the bottom of the borehole.

[0052] In the previous steps, there is a hollow area inside the long borehole grouting casing, which makes it easier for the long borehole grouting casing to float in the mud in the borehole, maintain a certain buoyancy and smoothness during the lowering process, reduce the friction between the casing and the hole wall, prevent the sediment below the inclined hole from affecting the lowering pipe, and avoid slow lowering of the casing causing hole collapse and the casing piercing the hole wall.

[0053] Step 7, use a drilling rig to lower a drill rod into the long borehole grouting casing to the front end of the long borehole grouting casing, sweep the front end of the long borehole grouting casing, and recycle the drill rod after the sweeping is completed; the sweeping operation is a conventional operation in the prior art, and the purpose is to remove the plug at the front end of the long borehole grouting casing to release the blockage at the front end of the long borehole grouting casing.

[0054] Step 8, using a positive circulation grouting method, injecting slurry into the long borehole grouting casing until the slurry fills the annular space between the long borehole grouting casing and the borehole wall and then returns from the ground, then stops grouting and waits for the slurry to solidify to form a consolidation layer;

[0055] Step 9, insert another oil casing of matching specifications into the inner wall of the long borehole grouting casing, and repeat step 8 again until the oil casing reaches the bottom of the borehole to further enhance the stability and durability of the overall structure; complete the installation of the long borehole grouting casing.

[0056] As a preferred solution, in step 2, multiple short-section grouting casings are divided into two groups of equal number, and the two groups of short-section grouting casings are connected end to end to form two grouting casings, so that the two groups of grouting casings can be connected end to end to form a long borehole grouting casing.

[0057] The purpose of this step is to reduce the welding operation time during the lowering of the short section grouting casing. Before the casing is lowered, the finished short section casing needs to be welded into a long tube on the ground. Due to site limitations, in this embodiment, the short section grouting casing to be lowered is welded into two grouting casings in advance, and the grouting casings are placed along the direction of the directional drilling, and the casing close to the hole mouth is placed along the soil slope.

[0058] In step 4, one end of the first grouting sleeve is used as the front end of the long borehole grouting sleeve to block the front end of the long borehole grouting sleeve;

[0059] In step 5, a plurality of cranes are used to jointly suspend the first grouting sleeve so that the first grouting sleeve does not deform;

[0060] Step 6, using multiple cranes to float the first grouting sleeve into the borehole, until most of the first grouting sleeve enters the borehole, multiple cranes move to the corresponding position of the second grouting sleeve, lift the second grouting sleeve and coaxially fix the second grouting sleeve to the rear end of the previous grouting sleeve to form a long borehole grouting sleeve;

[0061] Continue to lower the long drilling grouting casing until the front end of the long drilling grouting casing reaches the bottom of the borehole.

[0062] During actual construction, after multiple cranes complete the lowering operation of the first grouting sleeve in sequence, they move to the corresponding position of the second grouting sleeve in sequence, so that the two grouting sleeves do not deform when connected and do not affect the centering effect of the grouting sleeve in the borehole. Technical personnel in this field are capable of making adaptive adjustments based on actual conditions, including but not limited to adjusting the number of cranes and the position of lifting the grouting sleeve, which will not be repeated here.

[0063] Further preferably, after two-thirds of the first grouting sleeve enters the borehole, the second grouting sleeve is coaxially fixedly connected to the rear end of the first grouting sleeve to form a long borehole grouting sleeve. This setting is a preferred operation, and the first grouting sleeve has mostly entered the borehole, and the connection at this time can ensure the connection effect of the two grouting sleeves.

[0064] As a preferred solution, in step 4, a hemispherical or arc-shaped plug is used to seal the front end of the long drilling grouting casing.

[0065] The hemispherical or arc-shaped plug is conducive to the advancement of the long drilling grouting casing in the borehole. In order to facilitate the drilling tool to sweep away the plug during the subsequent pipe fixing, the plug can be made of wood or plastic.

[0066] As a specific implementation method, in step 5, three cranes are evenly arranged along the axial direction of the long borehole grouting casing;

[0067] At the same time, use slings to tie the long drilling grouting casing to the corresponding positions of the three cranes, use the crane to lift the corresponding slings, and then lift the long drilling grouting casing.

[0068] As a preferred solution, in step 6, when multiple cranes are used to float the long drilling grouting casing into the borehole, each time the sling lifted by a crane reaches the borehole mouth, the corresponding sling is untied; when the sling lifted by the last crane reaches the bottom of the hole, the corresponding sling is not untied;

[0069] In step 7, after the hole sweeping is completed, when the slurry liquid level in the long borehole grouting casing is restored to the same level as the slurry liquid level outside the long borehole grouting casing, the sling corresponding to the last crane is untied and the drill rod is recovered.

[0070] After the long borehole grouting casing is lowered to the bottom of the hole, in order to prevent the long borehole grouting casing from floating out of the hole under the action of buoyancy, the last crane cannot immediately untie the sling. A drilling rig should be used immediately to drill from the mouth of the long borehole grouting casing, and the plug of the long borehole grouting casing should be cleared. The sling can be untied only when the mud level in the long borehole grouting casing recovers to the same level as the mud level outside the long borehole grouting casing, and the drill tool lowered into the long borehole grouting casing can be pulled out.

[0071] As a preferred solution, in step 6, an excavator is set at the borehole mouth. In the process of using multiple cranes to float the long borehole grouting casing into the borehole, the excavator is used to continuously back-plane the long borehole grouting casing to assist in pushing the long borehole grouting casing.

[0072] In actual use, this setting is an optimal solution, allowing on-site construction workers to enter the borehole by hand with the casing head, and use the excavator to assist the long drilling grouting casing to slowly move and push the long drilling grouting casing into the borehole.

[0073] This setting took into account a variety of construction site equipment, and ultimately chose an excavator for assistance. Since the excavator can provide auxiliary propulsion to the long drilling grouting casing at multiple angles, and the excavator is a commonly used equipment on the construction site, using an excavator for assistance is the best choice during construction.

[0074] As a preferred solution, in step 6, before the long borehole grouting casing is lowered into the borehole in a floating manner using multiple cranes, lubricant is injected into the borehole, making it easier to lower the long borehole grouting casing into the borehole.

[0075] As a preferred solution, in step 9, the oil casing adopts API oil casing.

[0076] The method of the present invention has been applied in the production process of a certain enterprise. A specific embodiment is given below:

[0077] The top of the coal seam bedrock in a Jurassic coalfield in northern Shaanxi has been weathered to varying degrees, with loose structure, large porosity, developed cracks, strong water-richness and permeability, and abundant replenishment. Because the coal seam is shallowly buried, the mining cracks after the working face is mined can directly communicate with the bedrock weathering zone. The weathered bedrock aquifer is the main aquifer for mine water filling, and many coal mine roof water inrush incidents are related to this aquifer.

[0078] Through the method of advance grouting of the weathered bedrock aquifer, the voids and cracks in the weathered bedrock are sealed, the weathered bedrock aquifer is transformed, and its water richness and permeability are reduced to ensure safe mining at the working face.

[0079] The advance grouting of the weathered bedrock aquifer adopts a segmented forward grouting method based on directional drilling, that is, through a downward directional long borehole arranged on the ground, the borehole inclination is adjusted after reaching the bedrock weathering zone to ensure that the borehole trajectory is always in the weathered bedrock. The weathered bedrock aquifer is grouted through directional drilling, with every 50m as a grouting section. After the slurry solidifies, the drill bit is lowered from the hole mouth to sweep the hole to the bottom of the hole, drill 50m, lift the drill, and then grout from the hole mouth. This process is repeated to complete the grouting operation of a borehole.

[0080] The bedrock of the Jurassic coalfield in northern Shaanxi is covered with loose layers such as red soil, loess and aeolian sand. During directional drilling, it is necessary to lower the casing from the hole mouth into the bedrock, and use cement slurry to fix the pipe to ensure that the grouting pressure can be transmitted to the weathering zone of the bedrock during the grouting process. Since the loose layer is thick and the directional drilling is a downward drilling at a small angle, the casing length is generally large. Casing in the loose layer becomes a major difficulty in this type of project. When grouting the casing in the loose layer, the method of this embodiment is used to operate.

[0081] Step 1: In this embodiment, the length of the borehole from the opening to the 10m section entering the weathered bedrock is 288m, so the total length of the proposed grouting casing is 288m.

[0082] Step 2, in order to reduce the welding operation time during casing lowering, before casing lowering, the finished short section grouting casing needs to be welded into a long tube on the ground. Due to site limitations, in this embodiment, the casing to be lowered is welded into two grouting casings with a length of 144m, and the grouting casings are placed along the direction of the directional drilling.

[0083] In this embodiment, the diameter of the directional drilling hole is φ480 mm, and the outer diameter of the casing is φ377 mm.

[0084] Step 3, after drilling the downward sloping directional borehole with mud positive circulation until it enters the weathered bedrock for at least 10m, all drilling tools are removed, and the borehole wall can remain stable for a short time under the action of the mud wall protection in the hole. During this period of time, the grouting casing must be lowered immediately. Since the downward sloping directional borehole is a downward sloping borehole, in order to facilitate the grouting casing to adjust the angle of entering the borehole, a soil slope is constructed at the borehole mouth, and the slope angle of the soil slope is close to the downward angle of the directional borehole. The operation of setting the soil slope is a conventional operation in this field and will not be described in detail here.

[0085] Step 4, use a hemispherical plug to seal the front end of the long drilling grouting casing, wherein the hemispherical plug is made of wood or plastic.

[0086] Steps 5 and 6: The 144m grouting casing in this embodiment is constructed simultaneously by three cranes, which are respectively located at 40m, 80m and 120m from the front to the back of the grouting casing. After the crane suspends the grouting casing in the air, the on-site construction workers hold the grouting casing head by hand and use the excavator to assist the casing to move slowly, pushing the grouting casing into the borehole.

[0087] In addition, before lowering the long borehole grouting casing, a lubricating substance can be added to the mud in the borehole to reduce the friction between the casing and the hole wall and facilitate the lowering of the long borehole grouting casing. In this embodiment, a large amount of detergent is used for lubrication.

[0088] When the first grouting casing enters the hole for about 100m, the second 144m long grouting casing is immediately welded to the first grouting casing to form a long bored hole grouting casing. At the same time, the front crane is tilted to the rear and the casing is lifted with a sling, and so on to complete the lowering of the long bored hole grouting casing.

[0089] Step 7. After the long drilling grouting casing is lowered to the bottom of the borehole, in order to prevent the long drilling grouting casing from floating out of the borehole mouth under the action of buoyancy, the last crane cannot immediately untie the sling. The drilling rig should be used immediately to drill from the long drilling grouting casing, burn the plug in front of the long drilling grouting casing, and wait until the slurry level in the long drilling grouting casing recovers to the same level as the slurry level outside the casing before untying the sling and taking out all the drilling tools in the long drilling grouting casing.

[0090] Step 8, after the long borehole grouting casing is lowered, a grouting gate valve is installed at the pipe mouth of the long borehole grouting casing, and cement slurry is injected into the long borehole grouting casing until the cement slurry returns to the hole mouth from the outer wall of the casing, and the grouting is stopped and waited for solidification.

[0091] Step 9: Since the segmented progressive grouting based on directional drilling requires frequent drilling and drilling, the single-layer casing is easily damaged during the repeated drilling and drilling process, causing the grouting slurry to enter the loose layer. In order to ensure the reliability of the casing during grouting, a layer of wear-resistant casing is required to be inserted into the inner wall of the casing to protect the wall. In this embodiment, petroleum wear-resistant casing is selected.

[0092] Before lowering the wear-resistant casing, you need to use a drilling rig to sweep away the solidified cement from the original casing to the bottom of the hole, and then remove all drilling tools. The lowering and fixing method of the wear-resistant casing is the same as that of the original casing, so it will not be repeated here.

[0093] The wear-resistant casing used in this embodiment is an API petroleum casing with an outer diameter of Φ219.08 mm and a wall thickness of 4.2 mm.

[0094] At this point, the installation of the inclined directional long drilling grouting casing under the loose layer is completed. According to the actual results on site, the method of this embodiment effectively solves the problems of drill sticking, centering, hole collapse and offset, and significantly improves the casing lowering stability and construction speed. Through high-pressure grouting consolidation and secondary grouting consolidation of built-in wear-resistant ultra-long oil casing, the stability and durability of the overall structure are enhanced, the construction efficiency and safety are effectively improved, and it is suitable for large-scale use and promotion in industry.

Claims

1. A method for installing an inclined directional long drilling grouting casing under a loose layer, characterized in that: The following steps are involved: Step 1, determining the total length of the grouting casing required according to the length of the downward directional drilling hole that has been completed in the loose layer; Step 2, multiple short-section grouting sleeves are fixedly connected end to end in sequence until the length reaches the required total length of the grouting sleeve to form a long borehole grouting sleeve; Step 3, constructing a sloped soil platform in front of the completed downward directional drilling hole, making the slope of the soil platform consistent with the downward directional drilling hole and making the soil platform and the downward directional drilling hole collinear; Step 4, plugging the front end of the long drilling grouting casing; Step 5, multiple cranes are arranged along the axial direction of the long borehole grouting casing, and the long borehole grouting casing is suspended by the multiple cranes together so that the long borehole grouting casing does not deform; Step 6, using multiple cranes to float the long drilling grouting casing into the borehole until the front end of the long drilling grouting casing is lowered into the bottom of the borehole; Step 7, using a drilling rig to lower a drill rod into the long borehole grouting casing to the front end of the long borehole grouting casing, performing hole sweeping on the front end of the long borehole grouting casing, and recovering the drill rod after the hole sweeping is completed; Step 8, using a positive circulation grouting method, injecting slurry into the long borehole grouting casing until the slurry fills the annular space between the long borehole grouting casing and the wall of the downward inclined directional borehole and then returns from the ground, then stops grouting and waits for the slurry to solidify to form a consolidation layer; Step 9, insert another oil casing of matching specifications into the inner wall of the long borehole grouting casing, and repeat step 8 again after the oil casing reaches the bottom of the downward inclined directional drilling hole to complete the installation of the long borehole grouting casing.

2. The installation method of the inclined directional long drilling grouting casing under the loose layer according to claim 1 is characterized in that: In step 2, the plurality of short-section grouting sleeves are divided into two groups of equal number, and the two groups of short-section grouting sleeves are connected end to end to form two grouting sleeves, so that the two groups of grouting sleeves can be connected end to end to form a long borehole grouting sleeve; In step 4, one end of the first grouting sleeve is used as the front end of the long borehole grouting sleeve to block the front end of the long borehole grouting sleeve; In step 5, a plurality of cranes are used to jointly suspend the first grouting sleeve so that the first grouting sleeve does not deform; Step 6, using multiple cranes to float the first grouting casing into the downward inclined directional borehole, until most of the first grouting casing enters the borehole, multiple cranes move to the corresponding position of the second grouting casing, lift the second grouting casing and coaxially fix the second grouting casing to the rear end of the previous grouting casing to form a long borehole grouting casing; Continue to float down the long borehole grouting casing until the front end of the long borehole grouting casing reaches the bottom of the downward inclined directional borehole.

3. The method for installing the inclined directional long drilling grouting casing under the loose layer according to claim 2 is characterized in that: In step 6, multiple cranes are used to float the first grouting casing into the downward inclined directional borehole until two-thirds of the first grouting casing enters the downward inclined directional borehole, and then the second grouting casing is coaxially fixedly connected to the rear end of the first grouting casing to form a long borehole grouting casing.

4. The method for installing the inclined directional long drilling grouting casing under the loose layer according to claim 1 is characterized in that: In step 4, a hemispherical or arc-shaped plug is used to seal the front end of the long borehole grouting casing.

5. The method for installing the inclined directional long drilling grouting casing under the loose layer according to claim 1 is characterized in that: In step 6, in the process of floatingly pushing the casing into the downward inclined directional drilling hole with the cooperation of multiple cranes, each time the sling lifted by a crane reaches the hole mouth of the downward inclined directional drilling hole, the corresponding sling is untied; when the sling lifted by the last crane reaches the bottom of the hole, the corresponding sling is not untied; In step 7, after the hole sweeping is completed, when the slurry liquid level in the long borehole grouting casing is restored to the same level as the slurry liquid level outside the long borehole grouting casing, the sling corresponding to the last crane is untied and the drill rod is recovered.

6. The method for installing the inclined directional long drilling grouting casing under loose layer according to claim 1 is characterized in that: In step 6, an excavator is set at the mouth of the downward inclined directional drilling hole. In the process of floatingly pushing the casing into the downward inclined directional drilling hole with the cooperation of multiple cranes, the excavator is used to continuously back-scrape the long drilling grouting casing to assist in pushing the long drilling grouting casing.

7. The method for installing the inclined directional long drilling grouting casing under loose layer according to claim 1, characterized in that: Step 6: Before floating the grouting casing into the downward inclined directional borehole using multiple cranes, inject lubricant into the downward inclined directional borehole.

8. The method for installing the inclined directional long drilling grouting casing under loose layer according to claim 1 is characterized in that: In step 9, the oil casing adopts API oil casing.

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