Sleeve salvage method

Abstract

The invention provides a casing salvage method which comprises the steps that the lower end of a new casing is fixedly connected with a conical guide cone, the tip end of the guide cone faces downwards, and the new casing and the guide cone form a salvage part; the fishing part is put into the hydrological drill hole, and the initial gravity of the fishing part is recorded through an instrument located on the ground before the fishing part makes contact with the falling-in sleeve; the fishing part continues to be lowered so that the guide cone can be inserted into the upper end of the falling-in sleeve; rotating the new casing pipe, connecting an external thread at the lower end of the new casing pipe with an internal thread at the upper end of the falling-in casing pipe, and preliminarily judging whether the new casing pipe is in threaded connection with the falling-in casing pipe or not according to the rotating force applying condition; under the condition of preliminarily judging that the new casing pipe is connected with the falling-in casing pipe, the fishing part is lifted upwards, and whether the connection is good or not is secondarily judged according to the display of the instrument. By means of the method, a worker can confirm the connection condition of the new casing pipe and the falling casing pipe through numerical value comparison, repeated operation is avoided, the accuracy of fishing work is guaranteed, and the fishing efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogeological drilling, and in particular to a casing fishing method. Background Art

[0002] Water disasters are one of the major disasters currently encountered in coal mining. Before mining underground coal resources, conducting hydrogeological drilling to explore groundwater is the most important and reliable means. It is the only way to verify the results of hydrogeological mapping and hydrogeological exploration. It is also an essential project for conducting many hydrogeological experiments and the most important engineering means for exploiting groundwater.

[0003] Hydrogeological drilling plays a decisive role in the completion of the entire exploration task and the investment in the exploration project because of its complex and heavy equipment, high cost, complicated construction technology and long construction period.

[0004] For different hydrogeological survey tasks or different survey stages of the same survey task, the specific tasks of hydrogeological drilling are different, but the basic tasks are the same, that is, in addition to completing the geological drilling tasks, the following hydrogeological survey tasks need to be completed:

[0005] (1) Expose aquifers, explore the burial depth, thickness, lithology and hydraulic head height of aquifers, and identify the hydraulic connections between aquifers.

[0006] (2) Various hydrogeological tests are carried out with the help of hydrological drilling to determine the water richness of the aquifer (or the water yield of the well) and various hydrogeological parameters.

[0007] (3) Collect water and rock samples through hydrological boreholes (or during the drilling process) to determine the water quality of the aquifer and measure the physical, mechanical and hydraulic properties of the rock and soil.

[0008] (4) Use hydrological boreholes to monitor groundwater dynamics or use hydrological boreholes as water supply wells.

[0009] Hydrogeological drilling equipment is complex, heavy and expensive. During the hydrogeological drilling process, a casing needs to be installed in the hydrogeological borehole. Sometimes the casing is separated from the ground equipment and falls into the hydrogeological borehole. In the prior art, it is difficult to salvage the fallen casing, which eventually leads to the scrapping of the hydrogeological borehole. Summary of the invention

[0010] The invention provides a casing salvage method to solve the problem in the prior art that the casing dropped into a hydrological borehole is difficult to salvage.

[0011] In order to solve the above problems, the present invention provides a casing salvage method for salvaging a casing that has fallen into a hydrological borehole, comprising:

[0012] A conical guide cone is fixedly connected to the lower end of the new casing, with the tip of the guide cone facing downward, and the new casing and the guide cone form a salvage part;

[0013] Lowering the salvage part into the hydrological borehole, and recording the initial gravity of the salvage part by an instrument located on the ground before the salvage part contacts the dropped casing;

[0014] Continue to lower the salvage part so that the salvage part contacts the dropped casing, and the guide cone is inserted into the upper end of the dropped casing;

[0015] Rotate the new sleeve to connect the external thread at the lower end of the new sleeve with the internal thread at the upper end of the dropped sleeve, wherein it is preliminarily determined whether the new sleeve and the dropped sleeve are threadedly connected according to the rotation force;

[0016] In the case where it is preliminarily determined that the new casing is connected to the dropped casing, the salvage part is lifted upwards. If the gravity displayed by the instrument is greater than the initial gravity, it is confirmed that the new casing is well connected to the dropped casing; if the gravity displayed by the instrument is equal to the initial gravity, the new casing is not connected to the dropped casing, and the new casing is re-rotated for threaded connection;

[0017] When it is confirmed that the new casing and the dropped casing are well connected, a drilling tool is lowered into the new casing, and the guide cone is grinded or cut to break the guide cone, so that the new casing and the dropped casing are internally connected.

[0018] Furthermore, the guide cone is a hollow structure, and the large end of the guide cone and the lower end of the new sleeve are connected by welding.

[0019] Furthermore, the outer diameter of the large end of the guide cone is not greater than the inner diameter of the dropped sleeve.

[0020] Furthermore, the casing salvage method further comprises:

[0021] Before lowering the salvage unit into the hydrological borehole, the position of the upper end of the dropped casing in the hydrological borehole is detected.

[0022] Furthermore, the casing salvage method further comprises:

[0023] Flushing is performed inside the hydrological borehole to ensure the circulation of mud inside the hydrological borehole, so as to prevent the mud from settling and pressing the fallen casing.

[0024] Furthermore, during the grinding or cutting process of the guide cone, the generated iron filings are transported to the ground using mud liquid.

[0025] Furthermore, the new sleeve is rotated manually to perform threaded connection.

[0026] Furthermore, the casing salvage method further comprises:

[0027] When it is confirmed that the new casing is well connected to the dropped casing, the new casing is continued to be lowered into the hydrological borehole, and a plurality of the new casings are sequentially connected to the wellhead of the hydrological borehole.

[0028] Furthermore, before the dropped casing is lowered into the hydrological borehole, a water filter pipe is first lowered into the hydrological borehole, the lowering depth of the water filter pipe is the position of the aquifer to be observed in the hydrological borehole, and then the lower end of the dropped casing is connected to the upper end of the water filter pipe.

[0029] Furthermore, after the multiple new casings are connected to the wellhead of the hydrological borehole in sequence, a cementing vehicle is used to perform cementing treatment on the portion above the water filter pipe. After the cementing treatment is completed, a water stop test is performed in the hydrological borehole to observe whether the cementing is qualified.

[0030] The technical solution of the present invention is applied to provide a casing salvage method for salvaging a dropped casing that has fallen into a hydrological borehole, comprising: fixing a conical guide cone at the lower end of a new casing, with the tip of the guide cone facing downward, and the new casing and the guide cone forming a salvage part; lowering the salvage part into the hydrological borehole, and before the salvage part contacts the dropped casing, recording the initial gravity of the salvage part by an instrument located on the ground; continuing to lower the salvage part so that the salvage part contacts the dropped casing, and the guide cone is inserted into the upper end of the dropped casing; rotating the new casing, connecting the external thread at the lower end of the new casing with the internal thread at the upper end of the dropped casing, Among them, it is preliminarily judged whether the new casing and the dropped casing are threadedly connected according to the rotation force; when it is preliminarily judged that the new casing and the dropped casing are connected, the salvage part is lifted upwards, and if the gravity displayed by the instrument is greater than the initial gravity, it is confirmed that the new casing and the dropped casing are well connected; if the gravity displayed by the instrument is equal to the initial gravity, the new casing and the dropped casing are not connected, and the new casing is rotated again for threaded connection; when it is confirmed that the new casing and the dropped casing are well connected, the drilling tool is lowered into the new casing, and the guide cone is grinded or cut to break the guide cone so that the new casing and the dropped casing are connected internally. In this scheme, the staff lowers the salvage part composed of the new casing and the guide cone into the hydrological borehole, and the tip of the guide cone is set downward. Regardless of whether there is a gap between the dropped casing and the wall of the hydrological borehole, the tip of the guide cone can enter the dropped casing, so that the salvage part is in contact with the dropped casing, and the dropped casing and the new casing can be better threaded. The scheme also provides a gravity recording instrument to record the initial gravity of the salvage unit before placing it into the hydrological borehole. During salvage, the new casing and the dropped casing can be compared with the initial gravity to confirm whether they are well connected. In this way, the staff can confirm the connection between the new casing and the dropped casing by numerical comparison, avoiding repeated operations, ensuring the accuracy of the salvage work, and improving the salvage efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0032] Figure 1 A flow chart of the casing fishing method provided by the present invention is shown;

[0033] Figure 2 A schematic diagram showing an embodiment of the present invention applied to an inclined fall into a casing;

[0034] Figure 3 A schematic diagram of vertically falling into a casing provided by an embodiment of the present invention is shown.

[0035] The above drawings include the following reference numerals:

[0036] 10. Falling into the casing;

[0037] 20. New casing;

[0038] 30. Guide cone;

[0039] 40. External thread;

[0040] 50. Internal thread;

[0041] 60. Water filter pipe. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] like Figure 1 As shown, an embodiment of the present invention provides a casing salvage method for salvaging a dropped casing 10 dropped into a hydrological borehole. The casing salvage method comprises: fixing a conical guide cone 30 at the lower end of a new casing 20, with the tip of the guide cone 30 facing downward, and the new casing 20 and the guide cone 30 forming a salvage part; lowering the salvage part into the hydrological borehole, and before the salvage part contacts the dropped casing 10, recording the initial gravity of the salvage part by an instrument located on the ground; continuing to lower the salvage part so that the salvage part contacts the dropped casing 10, and the guide cone 30 is inserted into the upper end of the dropped casing 10; rotating the new casing 20, connecting the external thread 40 at the lower end of the new casing 20 with the internal thread 50 at the upper end of the dropped casing 10. Then, it is preliminarily determined whether the new casing 20 and the dropped casing 10 are threadedly connected according to the rotation force; when it is preliminarily determined that the new casing 20 and the dropped casing 10 are connected, the salvage part is lifted upwards, and if the gravity displayed on the instrument is greater than the initial gravity, it is confirmed that the new casing 20 and the dropped casing 10 are well connected; if the gravity displayed on the instrument is equal to the initial gravity, the new casing 20 and the dropped casing 10 are not connected, and the new casing 20 is rotated again for threaded connection; when it is confirmed that the new casing 20 and the dropped casing 10 are well connected, the drilling tool is lowered into the new casing 20, and the guide cone 30 is ground or cut to break the guide cone 30, so that the new casing 20 and the dropped casing 10 are internally connected.

[0044] In this embodiment, the staff lowers the salvage part composed of the new casing 20 and the guide cone 30 into the hydrological borehole, and the tip of the guide cone is set downward. No matter whether there is a gap between the dropped casing 10 and the wall of the hydrological borehole, the tip of the guide cone 30 can enter the dropped casing 10, so that the salvage part and the dropped casing 10 are in contact, and the dropped casing 10 and the new casing 20 can be better threaded. In this scheme, an instrument for recording gravity is also provided. Before the salvage part is placed in the hydrological borehole, the initial gravity of the salvage part is recorded. During salvage, it can be compared with the initial gravity to confirm whether the new casing 20 and the dropped casing 10 are well connected. In this way, the staff can confirm the connection between the new casing 20 and the dropped casing 10 by numerical comparison, avoiding repeated operations, ensuring the accuracy of the salvage work, and improving the salvage efficiency.

[0045] Figure 2 The figure shows the case where the casing 10 falls obliquely. Figure 3 The case where the casing 10 falls vertically is shown. Figure 2 and Figure 3 It can be seen from the figure that no matter whether the dropped casing 10 falls at an angle or not, the guide cone 30 can enter the dropped casing 10 , so that the dropped casing 10 and the new casing 20 can be threadedly connected.

[0046] The guide cone 30 is a hollow structure, and the large end of the guide cone 30 and the lower end of the new casing 20 are connected by welding. The guide cone 30 is set as a hollow structure, which can significantly reduce the weight of the entire salvage part, and can well reduce the burden of the salvage equipment and staff. At the same time, the hollow structure can use less material without sacrificing strength, which helps to reduce the cost of the entire equipment. Moreover, the guide cone 30 is set as a hollow structure, which can be more easily connected to the new casing 20 and easier to assemble.

[0047] Furthermore, the outer diameter of the large end of the guide cone 30 is not greater than the inner diameter of the dropped casing 10. This arrangement can ensure that the tip of the guide cone 30 can enter the dropped casing 10. In an ideal state, the guide cone 30 connected with the new casing 20 is at the most central position of the hydrological borehole, but there may be a gap between the dropped casing 10 and the wall of the hydrological borehole, and the guide cone 30 may be deflected. However, the outer diameter of the large end of the guide cone 30 is not greater than the inner diameter of the dropped casing 10. The guide cone 30 can ensure that it enters the dropped casing 10 through its unique tapered structure. Only in this way can the new casing 20 on the large end of the guide cone 30 be threadedly connected with the dropped casing 10.

[0048] Specifically, the casing salvage method further includes: before lowering the salvage unit into the hydrological borehole, detecting the position of the upper end of the dropped casing 10 in the hydrological borehole. Through this step of operation, it can be ensured in advance that the salvage unit can be connected to the dropped casing 10, avoiding invalid operations by operators and reducing time waste. Especially in those emergency situations where the response speed is extremely high, the application of this method can ensure the rapid and accurate implementation of the salvage operation, greatly improving the efficiency and success rate of emergency response.

[0049] Furthermore, the casing salvage method also includes: flushing the hydrological borehole to ensure the circulation of mud in the hydrological borehole to prevent the mud from settling and pressing the dropped casing 10. The setting of this part can help flush the casing by cleaning the hydrological borehole to prevent the dropped casing 10 from being pressed, and can also reduce the viscosity of the mud, thereby reducing the resistance during the salvage process. It can also prevent the dropped casing 10 from being blocked by the mud deposition, resulting in the guide cone 30 being unable to smoothly enter the dropped casing 10.

[0050] Specifically, during the grinding or cutting process of the guide cone 30, the iron filings generated are transported to the ground using mud. In this operation, the drilling tool is lowered into the new casing 20, and the unnecessary part of the guide cone 30 around the casing is ground or cut. Then, the iron filings generated by grinding or cutting are transported to the ground through mud circulation using mud and the aforementioned flushing operation of the hydrological borehole, thereby ensuring the safety of subsequent operations. At the same time, the hollow structure design of the guide cone 30 facilitates the entry of the drilling tool, which not only reduces the weight and cost of the salvage part, but also provides great convenience for the entry of subsequent drilling tools.

[0051] The new casing 20 is manually rotated for threaded connection. This part of the operation is manually operated to ensure that the dropped casing 10 and the new casing 20 are well threadedly connected. If a drilling rig is used for installation, the threads on the dropped casing 10 and the new casing 20 may be damaged, resulting in unstable threaded connection, which makes it impossible to carry out the salvage operation normally, thereby reducing secondary damage and repair costs caused by improper operation.

[0052] Furthermore, the casing salvage method also includes: after confirming that the new casing 20 and the dropped casing 10 are well connected, continue to lower the new casing 20 into the hydrological borehole, and multiple new casings 20 are connected to the wellhead of the hydrological borehole in sequence. After the salvage part is well connected to the dropped casing 10 and the guide cone 30 is polished or cut, multiple new casings 20 are connected to the wellhead of the hydrological borehole in sequence according to the hydrogeological drilling method, and the process before the casing falls into the hydrological borehole is continued to complete the work of the casing entering the hydrological borehole. In actual operation, the strategy of continuously lowering new casings 20 can significantly enhance the structural stability of the hydrological borehole, especially in those hydrological boreholes with greater depths. The application of this method can significantly extend the service life of the borehole and reduce the frequency and cost of borehole repair.

[0053] Specifically, before the drop-in casing 10 is lowered into the hydrological borehole, the filter pipe 60 is first lowered into the hydrological borehole, and the lowering depth of the filter pipe 60 is the position of the aquifer to be observed in the hydrological borehole, and then the lower end of the dropped-in casing 10 is connected to the upper end of the filter pipe 60. This operation ensures that the dropped-in casing 10 and the filter pipe 60 can be well connected, which can ensure the accuracy of the aquifer pumping test results, and also ensure that the measuring rope and other detection equipment can be smoothly lowered to the position to be observed during the later hydrological observation.

[0054] Furthermore, after a plurality of new casings 20 are sequentially connected to the wellhead of the hydrological borehole, a cementing vehicle is used to perform cementing treatment on the portion above the filter pipe 60. After the cementing treatment is completed, a water-stopping test is performed in the hydrological borehole to observe whether the cementing is qualified. The cementing treatment can enhance the stability of the hydrological borehole structure, and the water-stopping test ensures the sealing of the hydrological borehole, which is suitable for hydrological monitoring stations and geological exploration points that require long-term stable operation. In practical applications, the strategy of cementing treatment and water-stopping test can significantly improve the structural stability and sealing of the hydrological borehole, especially in those hydrological monitoring stations and geological exploration points that require long-term stable operation. The application of this method can significantly improve the accuracy of the data and the reliability of monitoring, and reduce data errors and monitoring failures caused by unstable hydrological borehole structure or poor sealing.

[0055] This casing salvage method realizes the effective salvage of the casing that has fallen into the hydrological borehole by using a combination of a guide cone 30 and a new casing 20, which not only improves the success rate of salvage, but also reduces the secondary damage to the hydrological borehole. By real-time monitoring of gravity changes, the connection between the new casing 20 and the fallen casing 10 can be accurately judged, avoiding the risks brought by blind operation. In addition, grinding or cutting the guide cone 30 ensures the connectivity between the new and old casings, providing convenience for subsequent drilling operations. Overall, this method is easy to operate, has significant effects, and has important application value for the maintenance and management of hydrological boreholes. Through actual case analysis, this method can effectively solve the problem of casing falling off in the well and ensure the safety and efficiency of energy extraction.

[0056] The above is only an optional embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0057] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0058] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being only exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0059] In the description of this scheme, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing this scheme and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the scope of protection of this scheme; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0060] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0061] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only to facilitate the distinction between corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this scheme.

Claims

1. A casing salvage method for salvaging a casing (10) that has fallen into a hydrological borehole, characterized in that: The casing salvage method comprises: A conical guide cone (30) is fixedly connected to the lower end of the new casing (20), the tip of the guide cone (30) faces downward, and the new casing (20) and the guide cone (30) form a salvage part; The salvage part is lowered into the hydrological borehole, and before the salvage part contacts the dropped casing (10), an initial gravity of the salvage part is recorded by an instrument located on the ground; The salvaging part is continued to be lowered so that the salvaging part contacts the dropped casing (10), and the guide cone (30) is inserted into the upper end of the dropped casing (10); Rotate the new sleeve (20) to connect the external thread (40) at the lower end of the new sleeve (20) and the internal thread (50) at the upper end of the dropped sleeve (10), wherein it is preliminarily determined whether the new sleeve (20) and the dropped sleeve (10) are threadedly connected according to the rotation force; When it is preliminarily determined that the new casing (20) and the dropped casing (10) are connected, the salvage part is lifted upwards. If the gravity displayed by the instrument is greater than the initial gravity, it is confirmed that the new casing (20) and the dropped casing (10) are well connected. If the gravity displayed by the instrument is equal to the initial gravity, the new casing (20) and the dropped casing (10) are not connected, and the new casing (20) is rotated again for threaded connection. When it is confirmed that the new casing (20) and the dropped casing (10) are well connected, a drilling tool is lowered into the new casing (20) to grind or cut the guide cone (30) to break the guide cone (30) so that the new casing (20) and the dropped casing (10) are internally connected.

2. The casing salvage method according to claim 1, characterized in that: The guide cone (30) is a hollow structure, and the large end of the guide cone (30) and the lower end of the new sleeve (20) are connected by welding.

3. The casing salvage method according to claim 1, characterized in that: The outer diameter of the large end of the guide cone (30) is not greater than the inner diameter of the dropped sleeve (10).

4. The casing salvage method according to claim 1, characterized in that: The casing salvage method further comprises: Before the salvage unit is lowered into the hydrological borehole, the position of the upper end of the dropped casing (10) in the hydrological borehole is detected.

5. The casing salvage method according to claim 1, characterized in that: The casing salvage method further comprises: Flushing is performed inside the hydrological borehole to ensure the circulation of mud inside the hydrological borehole, thereby preventing the mud from settling and pressing down the fallen casing (10).

6. The casing salvage method according to claim 5, characterized in that: During the grinding or cutting process of the guide cone (30), the generated iron filings are transported to the ground using mud liquid.

7. The casing salvage method according to claim 1, characterized in that: The new sleeve (20) is rotated manually to perform threaded connection.

8. The casing salvage method according to claim 1, characterized in that: The casing salvage method further comprises: When it is confirmed that the new casing (20) and the dropped casing (10) are well connected, the new casing (20) is continued to be lowered into the hydrological borehole, and a plurality of the new casings (20) are sequentially connected to the wellhead of the hydrological borehole.

9. The casing salvage method according to claim 8, characterized in that: Before the dropped casing (10) is lowered into the hydrological borehole, a water filter pipe (60) is first lowered into the hydrological borehole. The water filter pipe (60) is lowered to a depth equal to the position of the aquifer to be observed in the hydrological borehole. Then, the lower end of the dropped casing (10) is connected to the upper end of the water filter pipe (60).

10. The casing salvage method according to claim 9, characterized in that: After the multiple new casings (20) are connected to the wellhead of the hydrological borehole in sequence, a cementing vehicle is used to perform cementing treatment on the portion above the water filter pipe (60). After the cementing treatment is completed, a water stop test is performed in the hydrological borehole to observe whether the cementing is qualified.

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