Well wall coring drilling tool suitable for high-permeability stratum of open hole well

Abstract

The invention belongs to the technical field of drilling type coring devices in the petroleum geological exploration well logging technology, and discloses a well wall coring drilling tool suitable for an open hole well high-permeability stratum, the well wall coring drilling tool comprises a drill bit, and a plurality of chip removal holes are formed in the side wall of the drill bit at intervals; one end of the drill rod is connected with the drill bit, and a plurality of spiral hollow mud guide grooves are formed in the position, close to the drill bit, of the rod wall of the drill rod at intervals. The spiral hollow mud guide grooves are formed in the positions, close to the drill bit, of the rod wall of the drill rod at intervals, the scraping function is added to the inner wall and the outer wall of the drill rod, mud cakes on the well wall can be minced, the closed space of the mud cakes is destroyed, the mud cakes are thrown out of the drill bit through the rotation characteristic of the drill bit, and rock debris and the drill bit are scoured through mud; and finally, the purpose of discharging the rock debris out of the debris discharging hole is achieved, the resistance of rock core drilling is reduced, the probability of drill jamming is reduced, and the coring success rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling coring devices in petroleum geological exploration and well detection technology, and in particular relates to a well wall coring drill tool suitable for high permeability formations in open hole wells. Background Art

[0002] The borehole coring tools currently used in open hole wells are greatly affected by the formation characteristics and mud system, and have high requirements for well conditions. Before each coring operation, the well must be cleared and the mud cake around the wellbore must be scraped off. The mud specific gravity is 1.5g / cm 3 With the continuous expansion of rotary coring applications, the market has extended from exploration wells to development wells. Wellbore conditions and mud properties have become more complex, especially in high permeability (thick mud cake) formations, where the coring yield is greatly reduced.

[0003] In order to save costs, the original wellbore coring drill has several rows of mud holes on its drill rod. When coring in a high permeability layer, the drill bit will be wrapped by a thick mud cake. The rock cuttings produced after drilling into the formation are sealed by the mud cake. The mud and fluid in the wellbore cannot enter the formation rock being drilled. As the drill bit goes deeper, the drill bit is locked by the increasing and expanding rock cuttings, resulting in a drill stuck. In order to release the jam, the cable tension needs to be increased, which not only breaks the drill bit, but also damages the precision mechanical structure connected to the drill bit. This causes the instrument to be unable to continue to be used, and even logging and salvage engineering accidents to occur, which makes the coring operation face great engineering risks and greatly reduces the success rate of coring. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a borehole coring drill suitable for high permeability formations in open hole wells, which aims to reduce the resistance of core drilling, reduce the probability of drill sticking, and improve the success rate of coring.

[0005] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0006] A wellbore coring tool suitable for high permeability formations in open hole wells, comprising:

[0007] A drill bit, wherein a plurality of chip removal holes are provided at intervals on the side wall of the drill bit;

[0008] A drill rod, one end of which is connected to the drill bit, and a plurality of spiral hollow mud guide grooves are spaced apart on the rod wall of the drill rod near the drill bit.

[0009] Furthermore, a chip removal groove is provided on the drill bit at a position corresponding to each chip removal hole.

[0010] Furthermore, the width of the chip removal groove is 9 mm to 11 mm.

[0011] Furthermore, a plurality of the chip removal holes are evenly distributed along the circumference of the drill bit.

[0012] Furthermore, the rotation directions of the plurality of spiral hollow mud guide grooves are the same.

[0013] Furthermore, a drill rod positioning key groove is provided on the rod wall of the drill rod at a position away from the drill bit.

[0014] Furthermore, the wall thickness of the drill rod at the location where the spiral hollow mud guide groove is opened is 6 mm to 9 mm.

[0015] Furthermore, the diameter of the chip removal hole is 4 mm to 6 mm.

[0016] Furthermore, the drill bit and the drill rod are integrally formed.

[0017] Furthermore, the outer surface of the drill bit is a cemented surface inlaid with diamonds.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] The present invention provides a borehole coring drill adapted for high-permeability formations in open-hole wells. A plurality of spiral hollow mud guide grooves are provided at intervals on the rod wall of the drill rod near the drill bit, so as to realize the addition of a scraping function to the inner and outer walls of the drill rod, and the mud cake on the borehole wall can be crushed to destroy its closed space. The mud cake is thrown out of the drill bit by utilizing the rotation characteristics of the drill bit, so that the mud washes the rock cuttings and the drill bit, and finally the purpose of discharging the rock cuttings from the chip removal hole is achieved. In other words, the mud guide groove is spiral, which is conducive to the discharge of the mud cake, and in the state of high-speed rotation, it has the effect of cutting the mud cake, opening the channel between the well fluid and the drill bit, which is conducive to the cooling of the drill bit and the removal of chips, opening the thick mud cake wrapped around the drill bit, and establishing a smooth system of the drill bit, the formation and the mud, so that the core drilling resistance is reduced, the probability of the drill being stuck is reduced, and the success rate of coring is improved.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 2 is a schematic structural diagram of a well wall coring drill according to an embodiment of the present invention;

[0023] Figure 2 The present invention is a schematic diagram of the drill bit end face structure of a wellbore coring drill according to an embodiment of the present invention.

[0024] In the figure: 1-drill bit; 100-chip removal hole; 101-chip removal groove; 2-drill rod; 200-spiral hollow mud guide groove; 201-drill rod positioning keyway. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0026] Combination Figure 1 and Figure 2 As shown, an embodiment of the present invention is a wellbore coring drill tool suitable for high permeability formations in open hole wells, including a drill bit 1 and a drill rod 2, wherein a plurality of chip removal holes 100 are spaced apart on the side wall of the drill bit 1; one end of the drill rod 2 is connected to the drill bit 1, and a plurality of spiral hollow mud guide grooves 200 are spaced apart on the rod wall of the drill rod 2 near the drill bit 1.

[0027] Specifically, a plurality of spiral hollow mud guide grooves 200 are provided at intervals near the drill bit 1 on the rod wall of the drill rod 2, so as to realize the addition of a scraping function to the inner and outer walls of the drill rod 2, so as to crush the mud cake on the well wall and destroy its closed space. By utilizing the rotation characteristics of the drill bit 1, the mud cake is thrown out of the drill bit 1, so that the mud washes the rock cuttings and the drill bit, and finally the purpose of discharging the rock cuttings from the chip discharge hole 100 is achieved. In other words, the mud guide groove is spiral, which is conducive to the discharge of the mud cake, and under the state of high-speed rotation, it has the effect of cutting the mud cake, opening the channel between the well fluid and the drill bit, which is conducive to the cooling of the drill bit and the removal of chips, opening the thick mud cake wrapped around the drill bit, and establishing a smooth system of the drill bit, the formation and the mud, so as to reduce the resistance of the core drilling, reduce the probability of the drill being stuck, and obtain the high permeability formation core that geologists are concerned about.

[0028] Based on the above embodiment, as a more preferred embodiment, Figure 1 and Figure 2 As shown, a chip groove 101 is provided on the drill bit 1 at a position corresponding to each chip hole 100, that is, a chip hole 100 is provided in each chip groove 101, which is conducive to guiding the cuttings discharged from the chip hole 100 through the corresponding chip groove 101, thereby better preventing the blockage of cuttings.

[0029] Combination Figure 1 and Figure 2As shown, preferably, a plurality of chip removal holes 100 are evenly distributed along the circumference of the drill bit 1, so that the rock cuttings in all directions can be discharged evenly during the drilling process. For example, three chip removal holes 100 are evenly distributed along the circumference of the drill bit 1, and a chip removal groove 101 is provided at the corresponding position of each chip removal hole 100.

[0030] In some embodiments, Figure 1 As shown, the spiral hollow mud guide grooves 200 have the same rotation direction, ensuring that the spiral hollow mud guide grooves 200 can be evenly opened, thereby achieving better cutting and discharge effects on the mud cake.

[0031] In some embodiments, Figure 1 As shown, a drill rod positioning key groove 201 is provided on the rod wall of the drill rod 2 at a position away from the drill bit 1 , and the drill rod 2 can be quickly installed and removed through the drill rod positioning key groove 201 .

[0032] Preferably, the wall thickness of the drill rod 2 at the position where the spiral hollow mud guide groove 200 is opened is 6mm-9mm, the diameter of the chip removal hole 100 is 4mm-6mm, the diameter of the chip removal groove 101 is 9mm-11mm, and the drill bit 1 and the drill rod 2 are integrally formed. As the chip removal and mud guide groove areas increase, in order to ensure the strength of the drill bit and the realization of the above design, the outer diameter of the large-particle drill bit is adopted, and the inner diameter adopts the size of the conventional drill bit. The spiral design is realized by increasing the wall thickness of the drill rod, and the original split design of the drill bit and the drill rod is changed to an integral molding, which increases the strength of the drilling tool.

[0033] In some embodiments, the outer surface of the drill bit 1 is a bonding surface inlaid with diamonds. The integrated drill tool is processed in a CNC machine tool, and then the diamonds are inlaid and sintered on the end face of the drill bit. The bonding strength is consistent with the conventional drill bit manufacturing process, which will not be described in detail here.

[0034] The well wall coring drill tool of this embodiment has the following advantages: first, the end area of ​​the coring drill bit is increased, and the area of ​​the chip removal groove is enlarged to 1.5 times of the original; second, the mud discharge hole on the drill rod is changed into a spiral hollow mud guide groove, and the mud guide area is increased by 3 times. A hollow design is adopted, and at the same time, the outer wall of the drill rod forms a spiral shape that is conducive to scraping mud; third, the drill bit and the drill rod are turned into a whole, which not only increases the hollow area of ​​the drill bit, but also strengthens the strength of the drill bit.

[0035] Since the rock characteristics of the high permeability layer are relatively soft, the width of the chip removal groove of the drill bit of this embodiment is increased, the mud removal area of ​​the drill rod is increased, and the wall thickness of the drill rod is also increased by 1.5 times. By testing the hardness of the well wall coring drill tool of this embodiment, the torque reaches 7N.M without deformation, and the drill tool meets the use requirements. After actual well testing, the grape flower formation of Daqing Oilfield was selected for experiment. This formation is a typical high permeability formation. In order to ensure the pressure balance under the well during drilling, the mud cake in this formation is very thick. When using the original conventional well wall coring drill tool, the coring recovery rate is almost zero. After using the well wall coring drill tool of this embodiment, the success rate of coring reaches 60%, which solves the need of the oil field company to perform lithology analysis on these high-yield layers. The present invention allows the well wall coring drill tool to maintain the proper hardness and strength, changes the drill rod drill bit structure, and enhances the mud and rock debris removal capabilities.

[0036] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0041] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A coring tool for open hole wells with high permeability, characterized in that: include: A drill bit (1), wherein a plurality of chip removal holes (100) are provided at intervals on a side wall of the drill bit (1); A drill rod (2), one end of which is connected to the drill bit (1), and a plurality of spiral hollow mud guide grooves (200) are provided at intervals on the rod wall of the drill rod (2) near the drill bit (1).

2. The wellbore coring tool adapted for open hole high permeability formations according to claim 1, characterized in that: A chip removal groove (101) is also provided on the drill bit (1) at a position corresponding to each chip removal hole (100).

3. The wellbore coring tool adapted for open hole high permeability formations according to claim 2, characterized in that: The width of the chip removal groove (101) is 9 mm to 11 mm.

4. The wellbore coring tool adapted for open hole high permeability formations according to claim 1, characterized in that: A plurality of chip removal holes (100) are evenly distributed along the circumference of the drill bit (1).

5. The wellbore coring tool adapted for open hole high permeability formations according to claim 1, characterized in that: The spiral hollow mud guide grooves (200) have the same rotation direction.

6. The wellbore coring tool adapted for open hole high permeability formations according to claim 1, characterized in that: A drill rod positioning key groove (201) is provided on the rod wall of the drill rod (2) at a position away from the drill bit (1).

7. The wellbore coring tool adapted for high permeability formations in open hole wells according to claim 1, characterized in that: The wall thickness of the drill rod (2) at the position where the spiral hollow mud guide groove (200) is opened is 6 mm to 9 mm.

8. The wellbore coring drilling tool adapted for open hole high permeability formations according to claim 1, characterized in that: The diameter of the chip removal hole (100) is 4 mm to 6 mm.

9. The wellbore coring tool adapted for high permeability formations in open hole wells according to claim 1, characterized in that: The drill bit (1) and the drill rod (2) are integrally formed.

10. The wellbore coring tool adapted for high permeability formations in open hole wells according to claim 1, characterized in that: The outer surface of the drill bit (1) is a cemented surface inlaid with diamonds.

Images