CN114737900A - A static cyclone well flushing device and method for cleaning ground immersion boreholes - Google Patents

Abstract

The invention relates to the technical field of in-situ leaching and uranium mining, in particular to a static cyclone well flushing device and method for cleaning in-situ leaching boreholes. The device includes: the air compressor is connected with the gas delivery hose, and the gas delivery hose is connected with the steel pipe through a transition joint; the inner end of the steel pipe is provided with a swirl piece, and the swirl piece includes a guide cone and a cylinder welded to its bottom surface. The guide cone is a cone, and the swirl vanes are welded to the side of the cylinder at intervals; the thickness of the swirl vanes is narrow at the top and wide at the bottom; the top of the guide cone faces the end of the conversion joint. The method is as follows: put the steel pipe down into the filter or the sand settling tube at the bottom of the casing in the well; turn on the air compressor, gas enters the casing in the well through the gas transmission hose and the steel tube, and start the well cleaning; measure the sand settling tube in the well Record the sand settling height or borehole flow rate, turn off the air compressor after the well flushing requirements are met, lift the gas delivery pipe out of the wellhead, and the well flushing is completed. The invention has high well cleaning efficiency, simple operation and convenient manufacture.

Description

A static cyclone well flushing device and method for cleaning ground immersion boreholes

technical field

The invention relates to the technical field of in-situ leaching and uranium mining, in particular to a static cyclone well flushing device and method for cleaning in-situ leaching boreholes.

Background technique

In-situ leaching of uranium is a uranium mining and metallurgy process that selectively extracts and recovers uranium metal from sandstone uranium ore bodies with certain permeability under natural burial conditions by drilling with chemical solutions. In this process, the leaching agent needs to be injected into the ground, seepage along the ore bed, and leaching the uranium in the ore to form a leaching solution and be lifted out of the surface. After hydrometallurgical treatment, the metal uranium in the leaching solution is separated and recovered. During the mining process, under the action of the hydraulic gradient, the fine particles of mud and silt in the ore layer migrate to the direction of the pumping well, causing mechanical blockage; the leaching agent reacts with the ore to generate calcium, magnesium, iron, aluminum, etc. Chemical precipitation, causing chemical blockage. The pumping well filter and its surrounding formations are the most severe locations for mechanical and chemical blockages. Over time, part of the fine particles and chemical deposits entering the wellbore through the filter will remain on the inner wall of the filter, and some will be deposited in the sand tube at the lower part of the filter, and even part of the filter section will be buried, making the wellbore dirty. . The above phenomenon will lead to the reduction of the drilling fluid volume and the uranium concentration in the leachate, which will greatly affect the normal production and operation of the mine. In view of this, well washing has always been the most arduous daily work in in-situ leaching uranium mines, and the well-washing process is also an important research topic in the field of in-situ leaching uranium mining technology.

Generally, there are two types of well cleaning methods, chemical methods and physical methods. The chemical method requires the injection of chemical reagents into the blockage site to dissolve fine particles and chemical deposits through chemical reactions. However, the chemical reagents used often change the pH environment of the formation at the filter site, and then bring in some new impurity ions, which will adversely affect the hydrometallurgical processes such as leaching and subsequent adsorption, leaching, and precipitation. In addition, in a strict sense, the chemical method only plays the role of dissolution, and the blockage is not discharged from the wellhead, so it is necessary to supplement the physical method to discharge the blockage to the surface to achieve the purpose of dredging the filter and the pore channels of the surrounding formation. . The physical method of well flushing is to use the negative pressure shock, vibration, scouring and other effects generated by the well flushing equipment to dredge the pore channels of the filter and its surrounding formations and clean the sand settling tube at the bottom of the filter, such as the wall-breaking gun method, piston method, Compressed air method, gas-liquid mixed injection method and gas foam flushing method, etc. Among them, the most classic and most practical well cleaning method is the compressed air method.

The compressed air method means that the high-pressure air generated by the air compressor is sent into the drilling casing to a certain depth through the air transmission pipeline, and a gas-liquid mixture is formed in the annular space between the air pipe and the casing. The mixture moves upward, the specific gravity of the gas-liquid mixture changes from large to small from the bottom to the top, and the bubbles change from small to large. The bubbles burst when near the wellhead, and the gas and liquid are separated and ejected from the wellhead at the same time. At this time, the formation water will flow continuously and rapidly to the filter, into the wellbore, and then mixed with the compressed air to form a continuous gas-liquid mixture flowing out of the wellhead. The fine particles and chemical sediments in the filter and its surrounding formations, and the mud and sand in the sand settling tube are brought out of the surface with the gas-liquid mixture, so as to achieve the effect of well cleaning.

Although the compressed air method can achieve the purpose of cleaning drilling holes, there are still some shortcomings, mainly reflected in the following aspects:

(1) The cleaning of ground immersion drilling usually uses PE hose as the air transmission pipe. Since the density of the PE hose is slightly lighter than that of water, the air is sealed in the pipe during the lowering process. Therefore, it is often difficult to lower the air transmission pipe to the filter at one time. In the case of deep boreholes or near the sand surface, especially when the borehole is deep and the groundwater level of the ore-bearing layer is shallow, it is necessary to run down the air duct while cleaning the well. Even so, it is difficult for part of the borehole air supply pipe to be lowered to the filter part or the bottom end of the sand settling tube, and the sand settling in the sand settling tube cannot be completely cleaned, and the well cleaning work is laborious and time-consuming.

(2) The high-pressure fluid from the formation only impacts the blockage in the normal direction of the filter, and then flows out of the wellhead along the axial direction of the casing. Although the impact force on the blockage in the normal direction is great, the cleaning efficiency of the chemical precipitation that has been scaled on the inner wall of the filter (the wall between the filter holes) and the mud sand deposited in the sand settling tube is low.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a static swirling well cleaning device and method for cleaning ground immersion boreholes, which has high well cleaning efficiency, simple operation and convenient manufacture.

The invention provides a static swirling well flushing device for cleaning ground immersion boreholes, comprising: an air compressor, an air hose, a conversion joint, and a steel pipe;

The air compressor is connected with an air hose, and the air hose and the steel pipe are connected by a conversion joint;

The inner end of the steel pipe is provided with a swirl piece, the swirl piece includes a flow guide cone and a cylinder welded to its bottom surface, the flow guide cone is a cone, and the swirl blades are welded to the side of the cylinder at intervals ; The thickness of the swirl blade is a narrow upper and a lower wide gradually expanding type;

The top end of the guide cone faces the end of the adapter.

Preferably, the bottom of the cylinder is flush with the bottom end face of the steel pipe.

Preferably, the swirling element is welded to the inner end of the steel pipe.

Preferably, the diameter of the steel pipe is the same as the diameter of the gas delivery hose, and the steel pipe and the gas delivery hose are threadedly connected with a conversion joint, and the conversion joint is a steel-plastic conversion joint with a metal clamp.

Preferably, the diameter of the bottom end face of the guide cone is 0.35-0.65 times the inner diameter of the steel pipe, the height-diameter ratio of the guide cone is in the range of 1.5-3.5, and the height-diameter ratio of the cylinder is in the range of 1.5 to 3.5. 1.5 to 3.5.

Preferably, the swirl blades are composed of a plurality of helical blades, the number of which is even and at least 4, the blades are evenly arranged on the side of the cylinder, and the height of the swirl blades is consistent with the height of the cylinder .

Preferably, the ratio of the thickness of the upper end of the swirl vane to the diameter of the cylinder is in the range of 0.05-0.35, and the ratio of the thickness of the lower end to the thickness of the upper end is in the range of 1.5-3.0.

Preferably, the helix angle of the swirl vane ranges from 30° to 60°.

Preferably, the swirl member is made of 316L stainless steel or 304 stainless steel.

The invention provides a static swirling well flushing method for cleaning ground immersion boreholes, comprising the following steps:

Putting the steel pipe of the static cyclone well washing device for cleaning the ground immersion drilling described in the above technical solution into the filter or the sand settling pipe part of the bottom end of the casing in the well;

Turn on the air compressor, the gas enters the well casing through the gas delivery hose and the steel pipe, and starts to clean the well;

Measure and record the sand settling height of the sand settling tube in the well or the flow rate of the borehole. After the well flushing requirements are met, the air compressor is turned off, and the gas delivery tube is lifted out of the wellhead to complete the well flushing.

Compared with the prior art, the static swirl well washing device for cleaning ground immersion boreholes of the present invention adopts a diversion cone and a swirl blade to construct a swirl, and the coupled centrifugal force "introduces swirl, strengthens turbulence, and strengthens pulse". It has a compact structure and is not easy to be damaged; it adopts a gradually expanding blade with varying thickness to construct a tapered flow channel, which increases the fluid dynamic pressure and can form a high-speed swirl; the stainless steel with built-in metal guide cone and swirl vane is used. The pipe is suitable for the complex fluid environment of in-situ leaching of uranium, and can increase the self-weight of the gas delivery pipe, which is convenient for one-time lowering to the filter part or near the grit surface. The device design concept is clear, the method is easy to operate, and the well cleaning performance is excellent.

Description of drawings

Fig. 1 shows the structure schematic diagram of the static cyclone well flushing device for cleaning ground immersion boreholes;

Fig. 2 shows the schematic diagram of selecting fluid structure;

Figure 3 shows a schematic diagram of the flow of the blockage;

Figure 4 shows a schematic diagram of a single blade;

In the figure,

1- Air compressor, 2- Air hose, 3- Adapter, 4- Steel pipe, 5- Swirl piece, 6- Diversion cone, 7- Swirl vane, 8- Wellhead, 9- Casing, 10- tapered flow channel, 11- filter, 12- grit tube.

Detailed ways

In order to further understand the present invention, the embodiments of the present invention are described below with reference to the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the present invention.

The embodiment of the present invention discloses a static swirling well flushing device for cleaning in-situ immersion boreholes, as shown in FIG.

The air compressor 1 is connected with an air hose 2, and the air hose 2 and the steel pipe 4 are connected through a conversion joint 3;

The inner end of the steel pipe 4 is provided with a swirl piece 5, preferably, the swirl piece is welded to the inner end of the steel pipe, and the bottom of the cylinder is flush with the bottom end face of the steel pipe,

As shown in Figures 2 and 3, the swirling member 5 includes a diversion cone 6 and a cylinder welded to its bottom surface. The diversion cone 6 is a cone, and its function is to guide the gas to enter the swirl vanes uniformly 7 flow passages; swirl blades 7 are welded to the side of the cylinder at intervals to form a swirl passage; the essence of the swirl passage between the swirl blades is to change the axial flow fluid into a swirl fluid, that is, the fluid From linear motion to tangential motion, the coupled centrifugal force produces high-speed swirl to scour blockages and mud sand at the bottom of the well.

The top end of the guide cone 6 faces the end of the adapter.

The diameter of the steel pipe 4 is the same as the diameter of the gas delivery hose 2 , and the steel pipe 4 and the gas delivery hose 2 are threadedly connected with the conversion joint 3 , and the conversion joint 3 is a steel-plastic conversion joint with a metal clamp.

The diameter of the bottom end face of the guide cone 6 is 0.35-0.65 times the inner diameter of the steel pipe, the height-diameter ratio of the guide cone is in the range of 1.5-3.5, and the height-diameter ratio of the cylinder is in the range of 1.5- 3.5.

The swirl vanes 7 are composed of a plurality of helical vanes, the number of which is even and at least 4, the vanes are evenly arranged on the side of the cylinder, and the height of the swirl vanes is consistent with the height of the cylinder.

The thickness of the swirl blade 7 is narrow at the top and wide at the bottom, and the ratio of the thickness of the upper end to the diameter of the cylinder ranges from 0.05 to 0.35, and the ratio of the thickness of the lower end to the thickness of the upper end ranges from 1.5 to 3.0. The swirl vane of this design increases the fluid velocity and the fluid dynamic pressure by reducing the cross-sectional area of the flow channel, thereby constructing a high-speed swirl.

The bottom end of the swirl vane 7, that is, the bottom end of the cylinder is flush with the bottom end of the steel pipe, so that the formed high-speed swirl flow immediately enters the annular space between the gas delivery pipe and the casing in the well. .

The helix angle of the swirl blades 7 ranges from 30° to 60°.

The swirl member 5 is made of 316L stainless steel or 304 stainless steel. Appropriate selection should be made according to the acidity of the reagent used in in-situ leaching of uranium. For acid immersion, the material is 316L stainless steel; for neutral immersion, the material is 304 stainless steel.

The embodiment of the present invention also discloses a static swirling well flushing method for cleaning in-situ immersion boreholes, comprising the following steps:

Putting the steel pipe of the static cyclone well washing device for cleaning the ground immersion drilling described in the above technical solution into the filter or the part of the sand settling pipe at the bottom end of the casing in the well;

Turn on the air compressor, the gas enters the well casing through the gas delivery hose and the steel pipe, and starts to clean the well;

Measure and record the sand settling height of the sand settling tube in the well or the flow rate of the borehole. After the well flushing requirements are met, the air compressor is turned off, and the gas delivery tube is lifted out of the wellhead to complete the well flushing.

Its working principle is: the air is blown out by the air compressor 1 and enters the air hose 2, and enters the casing 9 through the wellhead 8. The air flows along the air hose 2 to the steel pipe 4 , and the connection between the air hose 2 and the steel pipe 4 can be through the steel-plastic conversion joint 3 . The airflow continues to flow downward along the steel pipe 4, and is evenly led by the guide cone 6 to the tapered flow channel 10 formed by the swirl vanes 7. At this time, the airflow changes from axial motion to tangential motion and enters the air hose 2. The annular space between the steel pipe 4 and the casing 9 forms a gas-liquid swirl mixture. Driven by high-pressure air, the gas-liquid mixture rotates and moves upward. From the bottom to the top, the specific gravity of the gas-liquid mixture changes from large to small, and the bubbles change from small to large. When the bubble bursts near the wellhead 8, the gas and liquid are separated and ejected from the wellhead at the same time. At this time, a huge pressure difference is formed between the casing 9 and the formation water, and the formation water quickly flows into the casing 9 through the filter 11, and forms gas with the gas from the gas hose 2 and the steel pipe 4 again. The liquid swirl mixture, the gas-liquid swirl mixture further agitates the sand settling in the sand settling tube 12 at the bottom of the well, flushes the channel and inner wall of the filter 11 and the inner wall of the casing 9, and rotates upward to carry the blockage out of the wellhead 8, so as to achieve Purpose of well cleaning.

For chemical scaling on the inner wall of the filter, providing tangential shear force is more conducive to removing the scaling; at the same time, a swirl field and a turbulent flow field are formed near the sand settling surface in the filter or casing, which is conducive to stirring the bottom sand settling. The upward movement can make the drilling cleaning work more efficient and thorough.

In addition, in the swirl field, the tangential velocity is distributed along the radial direction of the casing or filter as a "double vortex", that is, a quasi-forced vortex near the side wall and a quasi-free vortex near the center, and its maximum tangential velocity is the incident vortex. The distribution of tangential velocity is caused by the distribution of pressure in the swirl field. Compared with no swirl, the pulse effect of formation water entering the filter can be enhanced.

Compared with the compressed air method, the present invention introduces centrifugal force, which not only makes it easier to strengthen the turbulent flow in the well to drive the blockage to move, but also constructs a tangential force for dredging the downhole filter, flushing the inner wall of the filter, stirring the sand and flushing the inside of the casing. The wall provides a new technical support; at the same time, the use of the swirl outlet of the flow channel tapered can construct a high-speed swirl, and the faster the swirl speed, on the one hand, it is easier to wash the filter, sand settling tube and casing, on the other hand On the one hand, it is easier to carry the blockage to flow; also because of the swirl effect, the pressure inside the casing will be redistributed, which can enhance the pulse effect of the formation water entering the filter; Greater tolerance and less resistance when applied. Therefore, the present invention can greatly improve the effect of the existing well cleaning device without changing the original compressed air method installation method and without occupying additional space.

In order to further understand the present invention, the static cyclone well flushing device for cleaning in-situ immersion boreholes provided by the present invention will be described in detail below with reference to the embodiments, and the protection scope of the present invention is not limited by the following embodiments.

Example 1

Uranium leaching well in a certain area of Erlian Basin, Inner Mongolia

The depth of the uranium mine is more than 300m, the inner diameter of the pumping hole casing is DN 128mm; the design pressure of the fan is 5Mpa, the actual work is about 3.5MPa, the inner diameter of the air conveying pipe is DN 25mm, and the length of the steel pipe is 1m; The diameter of the circle is 9mm; the number of swirl blades is 6, that is, the blade rotation angle is 60° (360°/6=60°), the helix angle is set to 60°, the vertical height is 25mm, and the width is 7mm. The diameter of the cylinder is 9mm, which facilitates the welding of the blade and the inner wall of the gas delivery pipe. The thickness of the top of the blade is 1mm and the thickness of the bottom is 2mm, as shown in Figure 3.

According to the results of measuring the height of the sand in the sand tube, two wells with similar heights of sand were selected, with a height of about 6m. Connect the test device and run down the gas pipe to start cleaning the well. The test results show that the gas delivery pipe can be lowered into place at one time. Under the same operating parameters, when the sand settling height of the two wells is the same (sand settling height is less than 1m, it is 0.5-0.6m), the compressed air method is used. The time is about 2.5 hours, and the time used in the present invention is about 1.5 hours, and the efficiency is improved by 40%. It can be seen that, on the premise that the well flushing effect is equivalent, the present invention can save the well flushing time, indicating that the well flushing effect can be significantly improved after coupling centrifugal force.

Example 2

A uranium leaching well in a certain place in the Yili Basin, Xinjiang, is an in-situ leaching uranium uranium well that has been in operation for many years. During normal production, the pumping volume is generally greater than 4m ³ /h. When the pumping volume drops below 2m ³ /h, it is considered that the downhole blockage is serious. At this time, the purpose of well flushing is to increase the pumping volume.

The depth of the uranium mine is more than 350m, the inner diameter of the pumping hole casing is DN 128mm; the design pressure of the fan is 5MPa, the actual working is about 3.5MPa, the inner diameter of the air conveying pipe is DN 25mm, and the length of the steel pipe is 1m; the height of the guide cone is 20mm, and the bottom The diameter of the circle is 9mm; the number of swirl blades is 8, that is, the blade rotation angle is 45° (360°/8=45°), the helix angle is set to 50°, the vertical height is 25mm, and the width is 7mm. The diameter of the cylinder is 9mm, which is convenient for the welding of the blade and the inner wall of the gas delivery pipe, the thickness of the top of the blade is 1mm, and the thickness of the bottom is 1.5mm.

Through downhole television observation and sampling analysis, it was found that the casing and filter were seriously blocked, and the blocking species were mainly fine sand, flocculent coagulation and colloidal sedimentation. Two wells with pumping volume below 2m ³ /h were selected and named as Well A and Well B respectively. The pumping volume of Well A was about 1.85m ³ /h, and the pumping volume of Well B was about 1.80m ³ /h. Use the compressed air method to clean well A, and use the patent of the present invention to clean well B. Connect the test device and run down the gas pipe to start cleaning the well. The test results show that the gas delivery pipe can be lowered into place at one time. Under the same operating parameters, for Well A, when the pumping volume reaches 4.0 m ³ /h, the well cleaning time is about 4 hours; for Well B, when the pumping volume reaches 4.0 m 3 /h The volume reaches 4.0m ³ /h, and it takes about 3 hours to clean the well. Further, when the pumping volume reaches 4.0m ³ /h, continue to clean the well for 2 hours: for Well A, the pumping volume reaches 4.5m ³ /h; for Well B, the pumping volume reaches 5.2m ³ /h ( At this time, the sand settling heights of Well A and Well B are both lower than 1 m).

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A static cyclonic well cleaning apparatus for cleaning an earth-immersed borehole, comprising: the air compressor, the gas transmission hose, the adapter and the steel pipe;

the air compressor is connected with the air delivery hose, and the air delivery hose is connected with the steel pipe through the adapter;

the tail end of the interior of the steel pipe is provided with a rotational flow piece, the rotational flow piece comprises a flow guide cone and a cylinder welded with the bottom surface of the flow guide cone, the flow guide cone is a cone, and rotational flow blades are welded on the side surface of the cylinder at intervals; the thickness of the swirl vanes is gradually enlarged from top to bottom;

the top end of the diversion cone faces the adapter end.

2. A static cyclonic well-flushing apparatus for cleaning an inground borehole as claimed in claim 1 wherein the bottom of the cylindrical body is flush with the bottom end face of the steel pipe.

3. A static swirl well-flushing device for cleaning an inground borehole according to claim 1 wherein the swirl element is welded to the end of the interior of the steel pipe.

4. The static cyclone well-flushing device for cleaning ground immersed borehole according to claim 1 characterized in that the diameter of said steel pipe is the same as the diameter of said gas hose, the steel pipe and the gas hose are connected with the conversion joint by screw thread, said conversion joint is steel-plastic conversion joint, and the metal hoop is added.

5. The static cyclone well-flushing device for cleaning the ground-immersed borehole according to claim 1, wherein the diameter of the bottom end face of the diversion cone is 0.35-0.65 times the inner diameter of the steel pipe, the height-diameter ratio of the diversion cone ranges from 1.5 to 3.5, and the height-diameter ratio of the cylinder ranges from 1.5 to 3.5.

6. The static cyclone well-flushing device for cleaning ground-immersed boreholes as claimed in claim 1 characterized in that said cyclone blades consist of a plurality of helical blades, the number of which is even and at least 4, the blades are evenly arranged on the side of the cylinder, the height of said cyclone blades is identical to the height of said cylinder.

7. The static cyclone well-flushing apparatus for cleaning an earth-immersed borehole according to claim 1, wherein the ratio of the upper end thickness of said cyclone blade to the diameter of said cylindrical body is in the range of 0.05 to 0.35, and the ratio of the lower end thickness to the upper end thickness is in the range of 1.5 to 3.0.

8. The static cyclonic well-flushing apparatus for cleaning an earth-immersed borehole as claimed in claim 1, wherein the helical angle of the said cyclonic blade is in the range of 30 ° to 60 °.

9. The static cyclone well-flushing apparatus for cleaning an inground drilling hole of claim 1 wherein said cyclone is 316L stainless steel or 304 stainless steel.

10. A static rotational flow well washing method for cleaning an earth-immersed borehole is characterized by comprising the following steps:

placing a steel pipe of the static cyclone well washing device for cleaning the ground immersion borehole according to any one of claims 1 to 9 into a filter or a sand setting pipe part at the bottom end of an inner sleeve of the borehole;

starting an air compressor, enabling gas to enter an inner sleeve of the well through a gas hose and a steel pipe, and starting well washing;

and measuring and recording the sand setting height or the drilling flow of the sand setting pipe in the well, closing the air compressor after the well washing requirement is met, lifting the gas conveying pipe out of the well mouth, and finishing the well washing.

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