CN206220857U - A kind of alternately plow and the composite drill bit for scraping butt formula combined-breaking rock - Google Patents

Abstract

The utility model discloses a combined rock-breaking composite drill in alternate plowing and scraping modes, which mainly includes a drill body, a fixed cutting structure with cutting teeth, and at least one rotary cone rotatably connected with the composite drill. "Plough-type" teeth are arranged on the rotating cone, and the rotating cone can rotate relative to the drill bit body. Alternately, the rock is broken by plowing. This rock breaking method eats and squeezes the rock with a small impact. The rock breaking is mainly due to the failure of tensile stress. The plowing rock-breaking method of the "plowing" teeth and the shearing rock-breaking method of the cutting teeth on the fixed cutting structure are combined to break rocks, which not only improves the stability of the drill bit, but also improves the overall life of the drill bit and the rock breaking method. rock efficiency.

Description

A Composite Drill Bit Combined with Alternate Plowing and Scraping for Rock Breaking

technical field

The utility model belongs to the field of oil and gas drilling, in particular to a composite drill bit.

Background technique

In the history of oil and gas drilling, the utility model of rotary drilling is undoubtedly a milestone. The cutting tools for rotary drilling are the most common and widely used roller cone bits and PDC bits. And with the continuous development of superhard materials such as diamond, the PDC bit has become the main cutting tool in oil and gas drilling with its unique rock breaking method and good working performance in soft to medium hard formations. However, because the PDC drill bit mainly breaks rocks by shearing, it has poor adaptability in hard formations, low speed, short life, and is prone to tooth chipping, chipping, and severe wear. At present, roller cone bits are mainly used in hard formation drilling at home and abroad. The roller cone bit cuts rocks through combined effects such as impact crushing and shearing. It is mainly suitable for drilling in medium to hard formations. It is less effective in soft formations and prone to mud bumps. Tooth loss and severe wear are prone to occur under these conditions, which will eventually lead to the failure of the roller cone bit. In order to overcome the respective shortcomings of the roller cone bit and the PDC bit, according to the rock breaking and cutting characteristics of the roller cone bit and the PDC bit, and combining the advantages of the two, a roller cone-PDC hybrid bit was proposed.

At present, the structure of the existing roller cone-PDC hybrid drill bit at home and abroad is mainly a hybrid drill bit with a rolling cone and a fixed blade. When the drill bit is drilling, the cone first breaks the rock by impact, and then the PDC teeth on the fixed blade break the rock by scraping. Because the rock-breaking method of the cone is essentially different from that of the PDC, the cone mainly relies on impact to break rock, and the PDC is a fixed shear, which makes the impact formed by the cone during rock breaking greatly interfere with the PDC's fixed cutting. job stability. This combination of different working modes makes the PDC teeth of the PDC easily damaged, which affects the overall life of the drill bit. Moreover, the longitudinal vibration generated when the cone works makes the cutting depth of the PDC unstable, which reduces the overall rock-breaking efficiency of the drill bit. In actual use, the combination of the above-mentioned roller cone rolling impact and PDC scraping rock breaking method is easy to form repeated crushing areas and bottom well cushions at the bottom of the well, especially in deep well drilling, where the bottom well confining pressure is large and the water conservancy effect It is limited, which greatly affects the overall rock-breaking efficiency of the drill bit.

Utility model content

The purpose of this utility model is to provide a composite drill bit combined with alternate plowing and scraping to break rock. It proposes that the cone breaks rock by plowing, and the PDC cutting teeth on the fixed cutting structure break rock by tooth shearing. This combined rock-breaking method makes the cones work with less impact and stable work, which improves the working stability of the PDC during fixed cutting, the overall life of the drill bit and rock-breaking efficiency.

The utility model purpose is achieved through the following technical solutions:

A composite drill bit combined with alternate plowing and scraping for rock breaking, including a drill body, a fixed cutting structure with cutting teeth and at least one rotating cone, the cutting teeth on the rotating cone are "plough-type" teeth, The rotating cone has an axial offset relative to the center of the drill body; the "plowing" tooth has a characteristic surface A and a characteristic surface B, and the characteristic surface A is the centrosymmetric section of the tooth, and the projection of the tooth in the direction of the orthogonal plane of this surface is the characteristic surface B;

Feature surface A has the following geometric features:

a. The bottom of the tooth goes up to the parting surface is the fixed part, and the top of the tooth goes down to the parting surface is the plowing part;

b. From the parting surface to the direction of the tooth top, the curve of the plowed part converges in a wedge shape;

c. The angle formed by the stagnation tangent of the curves on both sides of the plowing part in the direction of convergence is 45° to 80°;

d. The tooth tip part of the plowing part curve is a circular arc, the arc width is not greater than 6mm, and the arc radius ranges from 2mm to 5mm;

Feature surface B has the following geometric features:

a. From the parting surface to the direction of the tooth top, the curve of the plowing part is conical;

b. The apex angle range of the cone is 45°～90°.

The composite drill bit of the utility model cuts and breaks rocks by combining the "plowing type" cutting teeth arranged on the rotating cone and the (PDC) cutting teeth on the fixed cutting structure, wherein at least one rotating cone is rotatably connected with the composite drill bit. The cone can rotate by itself relative to the bit body. Its characteristics are: because the cutting teeth on the rotating gear adopt the "ploughing type" teeth of this patent, the rotating gear breaks rocks in a new "ploughing" method different from the prior art, and the rotating gear The "plough-type" teeth on the rotating gear alternately break rocks by plowing, and after further compounding with the fixed cutting structure, the "plow-type" teeth on the rotating gear alternately break rocks by "ploughing", while the fixed The (PDC) cutting teeth on the cutting structure break the rock in the way of shearing and crushing. The "plough-type" teeth on the rotating gear alternately plow and break rocks, and its tangential rock-breaking effect conforms to the characteristics of shear rock-breaking, and its lateral rock-breaking is extrusion rock-breaking. Space creates an "adjacent" effect when breaking rocks. Referring to Figures 3 and 4, a in Figure 3 is a fractured body, b is a fragmented body, c is a dense core, d is a radial crack, and X in Figure 4 is a broken area. This rock-breaking effect makes the cones work with less impact and stable work, and it is easier to cut rocks and have higher rock-breaking efficiency, thus improving the working stability of the (PDC) cutting teeth during fixed cutting and improving the drill bit. The overall life and rock breaking efficiency.

Compared with the existing composite drill bits at home and abroad, the composite drill bit of the utility model proposes a different composite cutting and rock-breaking method, in which the cones cut and break rocks in an alternate "ploughing" rock-breaking method. The method is different from the previous cones that break rock through impact and shearing. When the conventional cones are working, the cones roll, and the contact between the teeth and the bottom of the well is carried out alternately with single teeth and double teeth. When the single tooth touches the bottom of the well, the center of the cone is at the highest position; when the double tooth touches the bottom of the well, the center position of the tooth drops. During the rolling process of the conventional roller cone, the center position of the roller cone is constantly exchanged up and down, so that the drill bit reciprocates up and down in the axial direction, which is the longitudinal vibration of the drill bit. The longitudinal vibration of the drill bit makes the teeth produce impact force, which breaks the rock by impact.

The toothed wheel described in this patent eats and crushes the rock with a tiny impact, and the rock is mainly broken due to tensile stress failure. Therefore, the impact force produced by the cone when cutting and breaking rock is small, which greatly reduces the influence of the previous cone on the working stability of the PDC during fixed cutting, thereby improving the service life of the drill bit and the rock-breaking efficiency.

In terms of specific structure, the "plough type" teeth of this patent are mainly different from the cutting teeth on the cones of the prior art in that:

Tooth top shape: The structure of the cutting teeth on the existing gear mainly meets the impact requirements of the teeth on the rock at the bottom of the well, and the teeth are required to be resistant to impact. Therefore, the structure of the top of the tooth is relatively "blunt". The "plowing type" teeth of this patent mainly meet the requirements of the teeth for eating rocks at the bottom of the well, and the teeth are required to be easy to chisel. Therefore, the top structure of the tooth is more "sharp".

Tooth structure division: The "ploughing type" tooth of this patent divides the whole tooth into two parts, the fixed part and the plowing part. Among them, the radial cross-sectional shape of the installation part is rich, which can be conventional circular, elliptical, etc., and can also be customized according to the formation conditions.

Plowing part: The "plowing type" tooth of this patent has a clear structure of the plowing part, as described in the description of the characteristic surface A and characteristic surface B of this tooth.

Alternatively, rotating cones with "plough-type" teeth alternate with fixed cutting structures with cutting teeth on the bit. In this scheme, the rocks at the bottom of the shaft are cut alternately by using the toothed wheel and the fixed cutting structure to cut and break the rock.

As an option, the ring gear on the rotating gear and the cutting teeth on the fixed cutting structure are not arranged on the same track in the radial direction of the drill bit (that is, the cutting trajectories are different tracks), and the "plowing" teeth on the rotating gear and the cutting teeth on the fixed cutting structure The cutting tracks of the cutting teeth are alternately staggered to form an alternating network cutting area. In this solution, the combined rock breaking method of alternate plowing and scraping will not form repeated broken areas at the bottom of the well, avoiding the formation of bottom well cushions, and its effect is better than that of the existing cone-PDC composite drill bit.

Alternatively, the well bottom trajectory of the "plough type" teeth on each ring gear of the rotating cone is not shallower than the cutting trajectory of the adjacent cutting teeth on the fixed cutting structure. In this scheme, when the bottom hole track of the "plowing" tooth on the cone is deeper than the cutting track of the cutting tooth adjacent to the cutting track on the fixed cutting structure, the "plowing" tooth first eats into the rock formation , Reduce the vibration of the drill bit and increase the stability of the drill bit when it is working.

Alternatively, the "plough type" teeth have a cone angle in the range of 45° to 80°. In this scheme, when the apex angle of the "plow-type" tooth is greater than 80°, the apex of the cone is too blunt, and the effect of cutting and breaking rocks becomes poor, while when the apex angle of the "plow-type" tooth is less than 45°, the apex of the "plow-type" tooth The points are relatively too thin and easy to break, affecting the life of the drill bit. However, when the apex angle of the "plowing" tooth ranges from 45° to 80°, its impact resistance and wear resistance are better during operation.

Alternatively, the positive cutting angle of the "plough type" teeth is 5° to 65°. In this scheme, the "plough type" teeth have two maximum stress areas along the tangential direction of the movement direction during work, which are respectively located on the two sides of the "plow type" tooth in front of the "plow type" teeth, and their plowing effect is obvious; During the plowing process, the "shaved" teeth will also squeeze the rocks on both sides, and multiple "ploughed" teeth will also produce an "adjacent" effect in the process of breaking rocks at the same time. This "adjacent" effect makes The ridge becomes more easily broken when cut again by the cutters on the fixed cutting structure.

As an option, the "plowing type" tooth is a conical tooth, that is, the part of the cutting tooth exposed to the cone is a cutting tooth of a conical surface with a cone tip and an arc transition. When plowing rock breaking, the cutting teeth used should be neither too sharp nor too blunt. If the cutting teeth are too sharp, they are easy to wear. If they are too blunt, the rock breaking method of the cutting teeth will change and the wear will increase. When the conical teeth break rocks by plowing, the broken shape of the rock surface is an inverted "Λ" shape, which can well control the wear of the cutting teeth and the way of breaking rocks, and satisfies the requirements of plowing and breaking rocks.

Alternatively, the ratio of the distance between the axis of the rotary cone and the axis of the drill bit to the diameter of the drill bit ranges from 0.05 to 0.25. In this solution, the greater the ratio of the distance between the axis of the rotating cone and the axis of the drill bit to the diameter of the drill bit, the slower the rotation speed of the rotating cone, and the lower the relative ratio of the rotation speed of the rotating cone to the revolution speed. By setting the different positions and angles of the rotary cone relative to the drill body and the different arrangements of the teeth on the rotary cone, the speed ratio of the rotary cone to the drill bit can be conveniently controlled and changed. When the composite drill bit is working, different wheel head speed ratios make the cutting effect of the rotating cone different during the drilling process. "Type" teeth work alternately and wear evenly. The small wheel head speed ratio makes the axial reciprocating motion of the drill bit smaller, which reduces the axial vibration of the drill bit. When drilling in hard formations, the periodic dynamic load impact on the cone bearing is also reduced accordingly. prone to fatigue failure.

As an option, the rotary cone is arranged on the drill bit body through the claws, the rotary cone is rotatably connected with the claws, and the claws are fixed to the drill body. In this solution, the rotating cone is directly fixed and installed on the drill body through the claws, and its axial load is directly transmitted to the drill body through the claws. This structure has a good bearing capacity and increases the reliability of the drill. The technology of this installation method is mature, which can reduce the production cost of the drill bit.

Alternatively, the rotary cone is rotatably coupled to the stationary cutting structure. In this scheme, due to the structure and working characteristics of the cone, it has a lubricating system, and the installation of the lubricating system will affect the size of the entire composite drill bit. In this structure, the lubrication system can be implanted into a fixed cutting structure, so that the structure size of the composite drill bit is more free. In addition, due to the limited space in the small-sized drill bit, the rotating cone is set on the fixed cutting structure through the tooth claw, which is beneficial to the shaft offset design of the cone and the overall structural size and hydraulic structure of the drill bit, and increases the volume of the cutting groove , and can avoid the wear of the claw back when the drill bit is working.

Alternatively, the fixed cutting structure is a fixed blade, and the cutting teeth on it are PDC teeth. In this solution, the most common fixed cutting structure is adopted: fixed blade + PDC teeth.

The aforementioned main scheme of the utility model and its further selection schemes can be freely combined to form multiple schemes, which are all schemes that the utility model can adopt and claim protection; and the utility model, (each non-conflicting selection) selection and Free combinations are also possible between other options. After understanding the solution of the utility model, those skilled in the art can understand according to the prior art and common knowledge that there are various combinations, all of which are technical solutions to be protected by the utility model, and are not exhaustive here.

Description of drawings

Fig. 1 is the structure schematic diagram that the rotary cone of the present invention is arranged on the claw;

Fig. 2 is the top view of Fig. 1 composite drill bit;

Fig. 3 is the schematic diagram (tangential direction) when "ploughing type" tooth "ploughing" rock on the drill bit cone of the present invention;

Fig. 4 is a schematic diagram of the "adjacent effect" when the "ploughing type" teeth on the drill bit cone of the utility model are "ploughing" rocks;

Fig. 5 is a schematic diagram of the radial well bottom coverage of the "plough-type" teeth on the cone of the utility model and the cutting teeth on the fixed cutting structure;

Fig. 6 is a schematic diagram of the bottom-hole cutting trajectory of the "plough-type" teeth on the cone of the utility model and the cutting teeth on the fixed cutting structure;

Fig. 7 is a schematic diagram of the positive cutting angle α when the "plough type" teeth on the drill bit cone of the present invention "plough" the rock;

Fig. 8 is a structural schematic diagram of the utility model in which the rotary cone is arranged on a fixed cutting structure;

Fig. 9 is a structural schematic diagram of the "plough type" tooth of the utility model;

Fig. 10 is a schematic diagram of the characteristic profile A of the utility model "plowing type" tooth;

Fig. 11 is a schematic diagram of the characteristic surface B of the "plowing type" tooth of the utility model;

Among them, 1 is the drill bit body, 2 is the fixed cutting structure, 3 is the claw, 4 is the rotating cone, 9 is the bottom cutting surface, 10 is the drill bit, 41 is the "plough type" tooth, and 21 is the cutting of the fixed cutting structure. Teeth, 22 are parting surfaces, 23 are fixed parts for installation, and 24 are plowing parts.

detailed description

The following non-limiting examples illustrate the invention.

As shown in Figures 1 to 4, a in Figure 3 is the fractured body, b is the fragmented body, c is the dense core, d is the radial crack, and X in Figure 4 is the broken area. A composite drill bit 10 combined with alternate plowing and scraping to break rocks, mainly comprising: a drill body 1, a fixed cutting structure 2 with cutting teeth 21, and at least one rotary cone 4 that is rotationally connected with the composite drill bit 10, such as As shown in Figures 1 and 2, the rotating cone 4 is arranged on the drill bit body 1 through the claws 3, the rotating cone 4 is rotationally connected with the claws 3, and the claws 3 are fixed to the drill body 1; or as shown in Figure 8, the rotating The cone 4 is directly rotatably connected to the fixed cutting structure 2 (fixed blade), instead of the rotary cone 4 being arranged on the drill bit body 1 through the claws 3 . The cutting teeth on the rotary cone 4 are "plowing type" teeth 41, the rotary cone 4 can rotate on its own relative to the drill body 1, and the rotary cone 4 has a certain axis offset relative to the center of the drill body 1, so that the rotary cone 4 can rotate on its own. The "plowing type" teeth 41 alternately break rocks by plowing, and the plowing rock breaking mode of the "plowing type" teeth 41 is combined with the shearing rock breaking mode of the cutting teeth 21 on the fixed cutting structure 2 broken rock.

As an option, the rotary cones 4 and the fixed cutting structures 2 with cutting teeth 21 are alternately arranged on the drill bit 10, as shown in Figures 1, 2 and 8, two rotary cones 4 and two with cutting teeth 21 ( The fixed cutting structures 2 (fixed blades) of PDC teeth) are arranged alternately.

As an option, the ratio of the distance between the axis of the rotary cone 4 and the axis of the drill bit 10 to the diameter of the drill bit 10 is in the range of 0.05-0.25.

Alternatively, the ring gear on the rotating cone 4 and the cutting teeth 21 on the fixed cutting structure 2 are not arranged on the same track in the radial direction of the drill bit 10 , as shown in FIG. 5 , so that the cutting tracks of the two are different. The cutting tracks of the "plowing" teeth 41 on the rotating cone 4 and the cutting teeth 21 on the fixed cutting structure 2 are alternately staggered to form alternate mesh cutting areas. As shown in Figure 6.

Alternatively, the bottom-hole track of the "plowing" teeth 41 on each ring gear of the rotating cone 4 is not shallower than the cutting track of the cutting teeth 21 adjacent to the cutting track on the fixed cutting structure 2 .

The "plowing type" tooth has a characteristic profile A and a characteristic surface B. The characteristic profile A is the central symmetrical section of the tooth (that is, a certain longitudinal section passing through the highest point of the tooth top, which divides the plowing part into left and right symmetrical sections. Two parts), the projection of the tooth in the direction of the orthogonal surface of the surface is the characteristic surface B (that is, another longitudinal section perpendicular to the characteristic surface A), see Figures 9, 10, and 11.

Feature surface A has the following geometric features:

a. The bottom of the tooth goes up to the parting surface 22 is the fixed part 23 (that is, the non-exposed part installed and fixed in the cone), and the top of the tooth goes down to the parting surface 22 is the plowing part 24 (that is, the part exposed in the exposed part outside the cone);

b. From the parting surface 22 to the direction of the tooth top, the curve of the plowed part 24 converges in a wedge shape;

c. The angle between the stagnation point tangent line and the convergence direction of the curves on both sides of the plowing part 24 is 45°～80°;

d. The tooth tip part of the plowing part 24 curve is a circular arc, the arc width D is not greater than 6mm, and the arc radius R ranges from 2mm to 5mm;

Feature surface B has the following geometric features:

a. From the parting surface 22 to the direction of the tooth top, the curve of the plowed part 24 is conical;

b. The apex angle β of the cone is in the range of 45° to 90°, more preferably between 45° and 80°.

Preferably, as shown in Figures 1-8, the "plowing" tooth 41 is a conical tooth, that is, the part of the cutting tooth exposed to the cone is a cutting tooth on a conical surface with a cone tip and arc transition. A preferred "plowing type" tooth is shown in Figures 9-11, which has a relatively regular conical plowing portion 24 and a characteristic profile A with a plowing portion 24 curve that is an asymmetrical figure, such as As shown in Figure 10, the characteristic surface A is curved to the right.

When the "plough type" is arranged, it is preferred that the "plow type" teeth 41 have a positive cutting angle α (that is, when the teeth are arranged, the plow part is made to face the cutting surface 9 at the bottom of the well and tilt forward along the cutting direction so that the direction of the tooth top is perpendicular to the The direction of the bottom hole cutting surface forms an included angle α, which is the positive cutting angle α of this patent. For conical teeth, that is, between the axis x of the tooth and the vertical line y of the bottom hole cutting surface 9 The included angle α) is between 5° and 65°. As shown in Figure 7.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (10)

1. a kind of alternately plow and the composite drill bit for scraping butt formula combined-breaking rock, including bit body, the fixation with cutting tooth are cut Cut structure and at least one and rotate gear wheel, it is characterised in that：It is " plow type " tooth to rotate the cutting tooth on gear wheel, rotates gear wheel phase There is axle offset to bit body center；It is the center pair of tooth that " plow type " tooth has tag type face A and characteristic face B, tag type face A Section, tooth is claimed to be projected as characteristic face B in the normal surface direction in the face；

Tag type face A has includes following geometric properties：

A. bottom of the tooth toward up to die joint be mounting part point, tooth top down to die joint be plow part；

B. from die joint to tooth top direction, the wedge shaped convergence of curve of plow part；

C. curve its stationary point tangent line in plow part both sides is restraining direction angle at 45 °~80 °；

D. its tip portions of plow partial trace are circular arc, and circular arc width is not more than 6mm, arc radius scope 2mm~5mm；

Characteristic face B has includes following geometric properties：

A. from die joint to tooth top direction, the curve of plow part is tapered；

B. the vertex of a cone angular region of taper is 45 °~90 °.

It is 2. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：Carry The rotation gear wheel of " plow type " tooth is disposed alternately on drill bit with the stationary cutting structure with cutting tooth.

It is 3. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：Rotate tooth The cutting tooth on gear ring and stationary cutting structure on wheel in drill bit, radially arrange by non-same rail, rotates " the plow type " on gear wheel Tooth replaces with the Cutting trajectory of the cutting tooth on stationary cutting structure and interlocks, and forms the netted cutting zone of alternative expression.

It is 4. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：Rotate tooth " plow type " the tooth well-bottom trace taken turns on each gear ring is not shallower than the cutting tooth of Cutting trajectory adjacent thereto on stationary cutting structure Cutting trajectory.

It is 5. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：" plow The vertex of a cone angular region of type " tooth is 45 °~80 °.

It is 6. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：" plow Type " tooth orthogonal cutting angle is 5 °~65 °.

It is 7. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：Rotate tooth The ratio range of the distance between wheel axis and drill axis and bit diameter is between 0.05-0.25.

It is 8. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：Rotate tooth Wheel is arranged on bit body by tooth pawl, is rotated gear wheel and is connected with the rotation of tooth pawl, and tooth pawl is fixed with bit body；Or, rotate tooth Wheel is directly rotatably connected on stationary cutting structure.

It is 9. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：" plow Type " tooth is conical tooth.

It is 10. as claimed in claim 1 to replace plow and the composite drill bit for scraping butt formula combined-breaking rock, it is characterised in that：It is fixed Cutting structure is fixing wing, and cutting tooth is PDC teeth thereon.