CN115680537A - A drilling debris collection device used in the hydraulic fracturing method for ground stress testing - Google Patents

Abstract

The application discloses a drilling debris collection device used in hydraulic fracturing ground stress testing. The bottom end of the drill pipe is connected in series with an upper collector, an upper packer, a fracturing section, a lower packer, a lower Collector, the upper and lower collectors are hollow tubular structures and several drainage holes are respectively arranged on the outer wall, the two ends of the upper collector are respectively connected with the drill pipe and the upper packer, and the top of the lower collector is sealed with the lower packer Connected, the outer diameters of the upper and lower collectors are equivalent to the corresponding upper and lower packers, and the upper collector communicates with the upper packer and is provided with a filter. In this application, upper and lower collectors with the same outer diameter and hollow tubular shape are respectively arranged on the outer sides of the upper and lower packers, and drainage holes are arranged on the outer walls of the upper and lower collectors, which can not only collect the debris falling during the ground stress test It can reduce the wear and damage of the packer by the debris during the up and down movement. It has the characteristics of simple structure, high drilling debris collection efficiency and low packer loss.

Description

A drilling debris collection device used in hydraulic fracturing method ground stress test

technical field

The application belongs to the technical field of geological exploration, and in particular relates to a drilling debris collection device for hydraulic fracturing ground stress testing with simple structure, high drilling debris collection efficiency and low packer loss.

Background technique

In the survey and design process of large-scale underground projects such as mining engineering and traffic tunnel engineering, it is usually necessary to focus on the influence of the in-situ stress field on the design and construction of underground engineering, and use it as an important basis for engineering design. Particularly important.

At present, in deep hole stress testing, hydraulic fracturing is a relatively common testing method due to its mature theory, simple operation, large measurement depth, low cost, and adaptability to testing of various hole diameters. The undisclosed underground engineering has initially identified the variation characteristics of ground stress with depth, and further judged the stability of underground engineering rockbursts and nearby geological structures. In the hydraulic fracturing method, during the test, a section of the borehole with exposed bedrock is selected to be sealed by a packer, and then liquid is injected through the fracturing section, and pressurized until the wall of the sealed hole ruptures, and then the pressure change data is collected and analyzed. And record or observe the rupture orientation with the impression device, and finally calculate the magnitude and direction of the principal stress of the original formation according to the pressure change and orientation data during the rupture process. However, the hydraulic fracturing method still needs to face the challenge of unfavorable geological conditions during the testing process. Among them, when the test borehole passes through a relatively broken section, the small debris falling from the hole wall not only directly affects the lifting operation of the hydraulic fracturing test equipment, but also after the small debris falls between the test equipment and the hole wall, , will increase the friction between the equipment and the hole wall, which will cause the test equipment to fail to lift and damage the rubber kit of the packer. In severe cases, the test equipment will be scrapped.

In the prior art, in order to solve the adverse effects of drilling debris on the test equipment, the debris falling from the upper part is generally considered, and a corresponding protection device is installed on the upper end of the packer, although it can reduce the impact of debris on the test equipment during the ascent process. The damage to the rubber kit of the packer can also avoid the problem of failure to ascend and recover; however, due to the fact that the debris wear on the broken hole wall and groundwater during the descent of the test equipment is not considered, and the impact of the groundwater in the hole on the existing The impact of the collected debris makes it difficult to prevent the rubber sleeve of the packer from being worn or even damaged during the descent, and the debris in the hole cannot be collected stably, thus affecting the subsequent accurate analysis of the law of ground stress changes. For this reason, in the prior art, rigid cones are respectively provided at the outer ends of the upper and lower packers, and protective sleeves are provided outside the drill pipe to collect debris on the upper part, so that during the lifting and lowering process The rubber sleeve is protected to reduce the loss of the packer; however, the cone only plays a protective role, and cannot solve the impact of the groundwater in the hole on the collected debris during the lifting of the test equipment, and may also increase the impact on the collected debris. The disturbance of groundwater in the hole makes it more difficult to collect drilling debris in the hole, which seriously affects the subsequent analysis and judgment of in-situ stress.

Contents of the invention

According to the deficiencies of the prior art, the present application provides a drilling debris collection device for hydraulic fracturing ground stress testing with simple structure, high drilling debris collection efficiency and low packer loss.

This application is achieved in the following way: it includes a drill pipe, and the bottom end of the drill pipe is detachably connected in series with an upper collector, an upper packer, a fracturing section, a lower packer, and a lower collector. The collector and the lower collector are hollow tubular structures respectively, and a number of drainage holes are arranged at intervals on the outer wall on the side away from the fracturing section. The top of the upper collector is sealed with the drill pipe and the lower end communicates with the upper packer. A filter screen with a pore size smaller than the drainage hole is arranged between the upper collector and the upper packer, the top of the lower collector is in sealing connection with the lower packer, and the outer diameter of the lower part of the upper collector is in contact with the outer diameter of the upper packer. The outer diameter of the upper part of the lower collector is equivalent to the outer diameter of the lower packer.

The beneficial effect of this application:

1. In this application, upper and lower collectors with the same outer diameter and hollow tubular shape are respectively installed on the outer sides of the upper and lower packers, and drainage holes are set on the outer walls of the collectors, and the upper collectors are connected with the upper packer And a filter screen is set in between, and through the cooperation of the drainage hole and the filter screen, the drilling debris during the lifting and lowering process of the test equipment can be efficiently collected, and the impact of the groundwater in the hole on the collected debris can be weakened during the lifting process. The impact effect can realize the stable and efficient collection of debris in the drill hole, which is conducive to improving the accurate analysis of the subsequent in-situ stress change law.

2. In this application, collectors with equivalent outer diameters are installed on the outer sides of the upper and lower packers, which can pre-shape the borehole wall during the lifting process, thereby reducing the wear and tear on the rubber set caused by the broken hole wall and debris in the groundwater. damage, ensuring the sealing of the rubber set, ensuring the accuracy of the ground stress test, and avoiding the problem that the test equipment cannot be recovered; and the cooperation between the drainage holes of the collector and the filter screen can not only reduce the number of drilling holes The debris in the inland groundwater can also prevent the collected debris from overflowing again, thereby further reducing the frictional damage of the debris to the packer, achieving the purpose of effectively reducing the loss of the packer and improving the efficiency of in-situ stress testing.

3. The application further sets the drain holes on the outer walls of the upper and lower collectors as inclined holes inclined to the collecting side, which is beneficial to the collectors to better capture debris in the groundwater in the borehole during the lifting process; and the upper 1. The drain holes on the outer wall of the lower collector are respectively set to a structure whose diameter gradually increases towards the outer side of the collection, which can realize the layered collection of debris, thereby effectively avoiding the blockage of the drain holes and affecting the collection of debris.

4. This application further sets a concave frustum groove at the end of the lower collector away from the lower packer, and sets a number of drainage holes or bottom openings on the inner wall of the frustum groove, so that the frustum groove can be used to filter groundwater Large-grain debris can avoid the wear of the packer by large-grain debris, and can facilitate the collection of debris for testing, which is conducive to improving the efficiency of debris collection.

In summary, the application has the characteristics of simple structure, high drilling debris collection efficiency, and low packer loss.

Description of drawings

Fig. 1 is one of the structure diagrams of the present application;

Figure 2 is the second structural diagram of the application;

Fig. 3 is a partially cut and enlarged view of Fig. 1;

Figure 4 is a partially cut and enlarged view of Figure 2;

In the figure: 1-drill pipe, 2-upper collector, 3-upper packer, 4-fracturing section, 5-lower packer, 6-lower collector, 7-drain hole, 8-filter, 9-Frustum I, 10-Frustum Groove, 11-Frustum II.

Detailed ways

The application will be further described below in conjunction with the accompanying drawings and embodiments, but the application is not limited in any way. Any changes or improvements made based on the teaching of the application belong to the protection scope of the application.

As shown in Figures 1 to 4, the application includes a drill pipe 1, and the bottom end of the drill pipe 1 is detachably connected in series with an upper collector 2, an upper packer 3, a fracturing section 4, and a lower packer 5 , the lower collector 6, the upper collector 2 and the lower collector 6 are respectively hollow tubular structures and the outer wall on the side away from the fracturing section 4 is provided with a number of drainage holes 7 at intervals, the top of the upper collector 2 and the The drill pipe 1 is tightly connected and the lower end communicates with the upper packer 3. A filter screen 8 with a diameter smaller than the drainage hole 7 is arranged between the upper collector 2 and the upper packer 3. The top of the lower collector 6 is connected to the upper packer 3. The lower packer 5 is sealed and connected, the outer diameter of the lower part of the upper collector 2 is equivalent to the outer diameter of the upper packer 3 , and the upper outer diameter of the lower collector 6 is equivalent to the outer diameter of the lower packer 5 .

The lower section of the outer wall of the upper collector 2 accounting for 1/3 to 1/2 of the total length is closed without drain holes 7, and the upper section of the outer wall of the lower collector 6 accounting for 1/3 to 1/2 of the total length is closed without setting drain hole7.

The axis of the drainage hole 7 on the outer wall of the upper collector 2 is perpendicular to the outer wall or inclined to the side of the drill pipe 1, and the axis of the drainage hole 7 on the outer wall of the lower collector 6 is perpendicular to the outer wall or away from the lower packer 5. sloping on one side.

The diameter of the drain hole 7 on the outer wall of the upper collector 2 gradually decreases axially toward the side of the packer 3, and/or the diameter of the drain hole 7 on the outer wall of the lower collector 6 moves axially downward toward the collector 6. side gradually decreases.

The drain hole 7 is a tapered hole with a large outside and a small inside.

The upper part of the upper collector 2 near the drill pipe 1 is provided with a hollow frustum I9, the top of the frustum I9 is detachably connected with the drill pipe 1, and the outer wall of the frustum I9 is arranged at intervals There are some drainage holes 7 . Since the opening of the drain hole 7 on the inclined frustum part I9 faces the capture direction, it can better capture debris to improve the capture effect, and it can also play a guiding role when shaping the hole wall.

The end of the lower collector 6 away from the lower packer 5 is closed and provided with a concave frustum groove 10, the opening direction of the frustum groove 10 is away from the lower packer 5, and the cone of the frustum groove 10 The bottom is sealed and a number of drainage holes 7 are arranged at intervals on the inner wall, or the conical bottom of the frustum groove 10 is provided with an opening.

The frustum groove 10 is coaxial with the lower collector 6; the drainage hole 7 on the outer wall of the lower collector 6 is arranged near the middle of the lower packer 5, and the drainage hole 7 on the inner wall of the frustum groove 10 is arranged on the side near the bottom of the cone.

The diameter of the drainage hole 7 on the inner wall of the frustum of the cone groove 10 or the diameter of the opening at the bottom of the cone is not smaller than the diameter of the drainage hole 7 on the outer wall of the lower collector 6 .

The lower part of the lower collector 6 away from the lower packer 5 is provided with a hollow frustum II11, and the outer wall of the upper part of the frustum II11 close to the lower packer 5 is provided with several drain holes 7 at intervals. The function of the inclined truncated part II11 is the same as that of the truncated part I9, so that debris can be better captured to improve the capture effect.

The upper collector 2 and the lower collector 6 are wear-resistant rigid hollow tubular structures such as steel or hard plastic.

The drill pipe 1, the upper collector 2, the upper packer 3, the fracturing section 4, the lower packer 5, and the lower collector 6 are sequentially connected by threads.

The working principle and working process of this application:

As shown in Figures 1 to 4, during the lifting process of the test equipment, the debris on the upper borehole wall falls under the friction and disturbance of the drill pipe 1, and the upper collector 2 is placed between the drill pipe 1, debris and the hole wall. During the friction of the groundwater, the debris enters the upper collector 2 through the collection hole (that is, the drainage hole 7) along with the groundwater, and enters the upper packer 3 through the filter screen 8 at the bottom to discharge the excess water body, so that the collected debris remains In the upper collector 2 on the upper end of the filter screen 8, and the smaller filter screen 8 of the aperture also ensures that the debris will not overflow the upper collector 2 again; Chips, debris can enter into it along with the water flow along the conical groove 10 and the collection hole (that is, the drain hole 7) at the bottom of the lower collector 6, and discharge excess water through the remaining drain holes 7, so that it enters the lower collector 6 The debris deposited therein also ensures that the debris will not overflow the lower collector 6 again. At the same time, during the lifting and lowering process of the test equipment, the rigid collector can also pre-shape the borehole wall, thereby reducing the wear and tear on the packer caused by the broken hole wall and debris in the groundwater. In addition, the truncated cones on the upper and lower sides of the collector can form a gradual shaping of the hole wall during lifting, thereby reducing or even eliminating the jamming of the broken hole wall to the lifting and lowering of the test equipment.

The above description is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. , should be covered within the protection scope of this application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (9)

1. A drilling debris collection device used in hydraulic fracturing ground stress testing, comprising a drill pipe (1), characterized in that the bottom end of the drill pipe (1) is detachable in series with upper Collector (2), upper packer (3), fracturing section (4), lower packer (5), lower collector (6), the upper collector (2) and lower collector (6 ) are hollow tubular structures and a number of drainage holes (7) are arranged at intervals on the outer wall on the side away from the fracturing section (4). The top of the upper collector (2) is sealed with the drill pipe (1) and the lower end and The upper packer (3) is connected, and a filter screen (8) with a diameter smaller than the drainage hole (7) is set between the upper collector (2) and the upper packer (3), and the lower collector (6 ) is in sealing connection with the lower packer (5), the outer diameter of the lower part of the upper collector (2) is equivalent to the outer diameter of the upper packer (3), and the upper outer diameter of the lower collector (6) It is equivalent to the outer diameter of the lower packer (5). 2. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 1, characterized in that the lower part of the outer wall of the upper collector (2) accounts for 1/3 to 1/2 of the total length One section is closed without drainage holes (7), and the upper part of the outer wall of the lower collector (6) accounts for 1/3 to 1/2 of the total length and is closed without drainage holes (7). 3. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 2, characterized in that the axis of the drainage hole (7) on the outer wall of the upper collector (2) is perpendicular to the outer wall Or inclined to the side of the drill pipe (1), the axis of the drainage hole (7) on the outer wall of the lower collector (6) is perpendicular to the outer wall or inclined to the side away from the lower packer (5). 4. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 2, characterized in that the diameter of the drainage hole (7) on the outer wall of the upper collector (2) is along the axial direction The upper side of the packer (3) gradually decreases, and/or the diameter of the drainage hole (7) on the outer wall of the lower collector (6) gradually decreases axially toward the lower side of the collector (6). 5. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 2, characterized in that the upper part of the upper collector (2) near the drill pipe (1) is provided with a hollow The frustum part I (9), the top of the frustum part I (9) is detachably sealed with the drill pipe (1), and the outer wall of the frustum part I (9) is provided with a number of drainage holes at intervals ( 7). 6. According to any one of claims 1 to 5, the drilling debris collection device used in hydraulic fracturing stress testing, characterized in that the lower collector (6) is far away from the lower packer (5 ) is closed at one end and provided with a concave frustum groove (10). A plurality of drainage holes (7) are arranged at intervals on the inner wall, or an opening is arranged at the bottom of the cone of the frustum groove (10). 7. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 6, characterized in that the frustoconical groove (10) is coaxial with the lower collector (6); The drainage hole (7) on the outer wall of the lower collector (6) is arranged in the middle, and the drainage hole (7) on the inner wall of the frustum of the cone (10) is arranged on the side near the bottom of the cone. 8. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 7, characterized in that the diameter of the drainage hole (7) or the bottom of the cone on the inner wall of the frustum of the cone (10) The opening aperture is not less than the drain hole (7) aperture on the outer wall of the lower collector (6). 9. The drilling debris collection device used in hydraulic fracturing ground stress testing according to claim 7, characterized in that the lower part of the lower collector (6) away from the lower packer (5) is provided with Hollow frustum part II (11), the outer wall of the upper part of the frustum part II (11) close to the lower packer (5) is provided with several drainage holes (7) at intervals.

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