Double-channel side-spraying PDC drill bit for drilling and coring in argillization interlayer stratum
Technical Field
The utility model belongs to the technical field of the PDC drill bit technique and specifically relates to a argillization intermediate layer stratum creeps into and gets core and spout the PDC drill bit with binary channels side.
Background
In the hydro-junction engineering projects at home and abroad, argillization interlayers are developed in a plurality of dam foundations or slope rock bodies, wherein the influence of the argillization interlayers needs to be considered in the construction of at least 1/3 dams. The argillization interlayer has the characteristics of weak lithology, poor water-based property and extremely low mechanical strength, the thickness of the argillization interlayer is generally between 1 and 3cm, and the small amount of the argillization interlayer can reach 10 to 30 cm. The soft structural surface is used as a common special weak structural surface in a stratified rock mass, has adverse effects on the anti-sliding stability of the rock mass, even becomes a control factor of the stability of engineering rock masses such as dam foundations, side slopes, caverns and the like, and is one of major engineering geological problems which need to be found in a plurality of fields including water conservancy and hydropower engineering.
Drilling coring is still an irreplaceable technical means for visually acquiring underground geological information (including argillaceous interlayers) at present. Drilling a high-quality argillized interlayer core is a target pursued in the field of water conservancy and hydropower engineering investigation all the time because argillized interlayers have weak lithology, poor water conservancy, poor mechanical strength and are easy to erode.
A double-pipe side-spraying PDC drill bit (patent number: ZL 202021796431.0) for clear water drilling and coring in a argillization interlayer is developed by yellow river survey planning and design research institute, and applied to practical engineering, and compared with the coring effects of a conventional casing drilling core drill, a pumpless reverse circulation drill, a vegetable gum core drill and the like, the quality of the argillization interlayer core is remarkably improved. This double-barrelled side spouts PDC drill bit is through setting up the side water jet hole, the circulation mode of flush fluid has been changed, the erosion effect of flush fluid to the rock core has been reduced or avoided, but this kind of structural style also leads to the empty flush fluid flow of this drill bit leading drill bit cutting tooth to show the decline, can not in time take away the rock powder that leading cutting tooth was carved and was got, the phenomenon of rock powder parcel cutting tooth and rock powder parcel rock core appears, rock powder parcel cutting tooth can lead to the drilling rate to reduce, rock powder parcel rock core can influence the purity of rock core, influence the accuracy that on-the-spot geology personnel judged.
Disclosure of Invention
In order to solve the problem, further improve the core drilling rate and the core of argillization intermediate layer stratum and bore and get the quality, the utility model provides a argillization intermediate layer stratum creeps into and gets core and spout PDC drill bit with binary channels side, specifically can take following technical scheme:
argillization intermediate layer stratum creep into and get core and spout PDC drill bit with binary channels side, include
The inner side of the top of the advanced drill bit is provided with a first step, and the first step is arranged in a clearance with the clamp spring seat;
the rear drill bit is sleeved on the outer side of the advanced drill bit and connected with the tail of the advanced drill bit, a second step and a third step are formed at the joint of the rear drill bit and the advanced drill bit, the second step is positioned on the outer side of the advanced drill bit, and the third step is positioned on the inner side of the rear drill bit;
the first side jet hole is formed in the rear drill bit, the inlet end of the first side jet hole is formed in the third step, and the outlet end of the first side jet hole is formed in the second step;
the inlet end of the second side jet hole is arranged on the third step, and the outlet end of the second side jet hole is arranged on the outer side wall of the leading drill bit;
the inlet ends of the first side jet holes and the second side jet holes are communicated with a flow passage formed by the rear drill bit and the clamp spring seat; when the drilling fluid flows out of the flow channel, the drilling fluid reaches the inlet end of the first side spray hole, one part of the drilling fluid returns to the ground along the gap between the rear drill bit and the borehole wall, and the other part of the drilling fluid flows to the outlet end of the first side spray hole from the inner side to the outer side of the front drill bit around the front drill bit to form a first circulating flow; meanwhile, the drilling fluid flowing out of the flow channel reaches the inlet end of the second side spray hole, one part of the drilling fluid enters the second side spray hole to reach the outlet end and returns to the ground along the gap between the advancing drill bit and the drilling well wall and the rear drill bit, and the other part of the drilling fluid flows to the outlet end of the second side spray hole from the inner side to the outer side of the advancing drill bit around the advancing drill bit to form a second circulating flow.
The first step is of an annular structure, and an annular buffer groove is formed in the first step.
The clearance between the first step and the clamp spring seat is 1-3 mm.
The first side spray holes are linear holes which are obliquely and outwards arranged, and the second side spray holes are L-shaped holes.
The PDC cutting teeth are uniformly distributed on the bottom surfaces of the leading drill bit and the rear drill bit, are brazed with the leading drill bit/the rear drill bit at the same insert welding angle and the same bypass angle, and are arranged on the leading drill bit and the rear drill bit in a vertically staggered mode.
The welding angle between the PDC cutting teeth and the leading drill bit/the rear drill bit is 10-15 degrees, and the bypass angle between the PDC cutting teeth and the leading drill bit/the rear drill bit is 5-15 degrees.
A plurality of mounting bulges are arranged on the second step at intervals, and one side of each mounting bulge is connected with the PDC cutting tooth in a brazing mode.
And outlet ends of the first side jet hole and the second side jet hole are arranged close to the PDC cutting teeth.
A plurality of spiral guide grooves are arranged on the outer side surface of the leading drill bit at intervals.
The direction of the spiral guide groove is consistent with the rotating direction of the drill bit, and one end of the spiral guide groove corresponds to the position of the outlet port of the second side spray hole.
The utility model provides a argillization intermediate layer stratum creeps into and gets core and spout PDC drill bit with binary channels side, and the structure is exquisite, convenient to use, low cost, not only can reduce or avoid the flush fluid to argillization interbedded erosion effect, also can in time take away the rock powder that the leading bit cutting tooth was carved and is got simultaneously, solves the problem of rock powder parcel core, rock powder parcel cutting edge, is showing and is improving argillization intermediate layer core and bores and get the quality and creep into efficiency.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a cross-sectional view of fig. 1.
Fig. 3 is an enlarged view of a portion a in fig. 2.
Fig. 4 is an enlarged view of a portion B in fig. 2.
Fig. 5 is a bottom view of fig. 1.
Fig. 6 is a use state diagram of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the embodiments of the present invention are based on the technical solutions of the present invention and are described in detail, but the present invention is not limited to the following embodiments.
As shown in figures 1-5, argillization interbedded layer stratum creeps into and gets core and spout PDC drill bit with binary channels side, by the leading drill bit 1 and the back drill bit 2 that the integration set up to and communicate the inside and outside first side orifice 3 and the second side orifice 4 of drill bit and constitute. A clamp spring seat M is arranged in the leading drill bit 1 and the rear drill bit 2, and a drilling fluid flow channel N is formed by the gap arrangement of the clamp spring seat M and the rear drill bit 2.
Specifically, the diameter of the leading drill bit 1 is smaller than that of the rear drill bit 2, and the rear drill bit 2 is sleeved outside the leading drill bit 1 and connected with the tail of the leading drill bit.
The bottom surfaces of the two cutter bodies are respectively provided with three PDC cutting teeth 5 which are uniformly distributed, each PDC cutting tooth 5 is connected with the advanced drill bit 1/the rear drill bit 2 in a brazing mode through the same welding angle (about 10-15 degrees) and the same bypass angle (generally 5-15 degrees), the PDC cutting teeth 5 on the advanced drill bit 1 and the rear drill bit 2 are arranged in a vertically staggered mode, and each PDC cutting tooth 5 on the advanced drill bit 1 is correspondingly arranged between two adjacent PDC cutting teeth 5 on the rear drill bit 2. Three spiral guide grooves 6 are arranged on the outer side surface of the leading drill bit 1 at intervals, an annular first step 7 is arranged at the top of the inner side surface of the leading drill bit, the clamp spring seat M is embedded into the first step 7, and the bottom of the clamp spring seat M is 1-3mm away from the end surface of the first step 7. In addition, the first step 7 is provided with an annular buffer groove 8 for reducing the flow rate of the drilling fluid. The joint of the rear drill bit 2 and the advance drill bit 1 forms a second step 9 and a third step 10, wherein the second step 9 is positioned outside the advance drill bit 1, three mounting bulges 11 for welding PDC cutting teeth 5 are arranged on the second step 9 at intervals, and the PDC cutting teeth 5 are positioned on the same side of the mounting bulges 11; a third step 10 is provided inside the rear drill 2 above the first step 7. The first side spray hole 3 is positioned on the rear drill bit 2, the inlet end of the first side spray hole is arranged on the third step 10, the outlet end of the first side spray hole is arranged on the second step 9, and a linear hole which is inclined from top to bottom and is arranged outwards is formed; the second side jet hole 4 is located between the leading drill bit 1 and the rear drill bit 2, the inlet end of the second side jet hole is arranged on the third step 10, and the outlet end of the second side jet hole is arranged on the outer side wall of the leading drill bit 1 to form an L-shaped hole. The inlet ends of the first side jet holes 3 and the second side jet holes 4 are communicated with a drilling fluid flow passage N formed by the rear drill bit 2 and the clamp spring seat M, the outlet ends are arranged close to the corresponding PDC cutting teeth 5, and the outlet ends of the second side jet holes 4 are close to the bottom ends of the corresponding spiral guide grooves 6. The direction of each helical guide groove 6 is the same as the rotation direction of the drill bit.
During operation, as shown in fig. 6, the drilling fluid flowing out of the flow channel N reaches the inlet end of the first side spray hole 3, one part of the drilling fluid returns to the ground along the gap between the rear drill bit 2 and the borehole wall, and the other part of the drilling fluid flows around the leading drill bit 1 from the inner side to the outer side to the outlet end of the first side spray hole 3 to form a first circulating flow; meanwhile, the drilling fluid flowing out of the flow channel N reaches the inlet end of the second side spray hole 4, one part of the drilling fluid enters the second side spray hole 4 and reaches the outlet end and returns to the ground along the gap between the advance drill bit 1 and the rear drill bit 2 and the wall of the drilling well, and the other part of the drilling fluid flows around the advance drill bit 1 from the inner side to the outer side of the advance drill bit to the outlet end of the second side spray hole 4 to form a second circulating flow.
It can be seen that the first side jet hole 3 and the second side jet hole 4 can change the flow direction of the drilling fluid from the flow passage N between the jump ring seat M and the drill bit. Firstly, most of the drilling fluid flows out of the first side jet hole 3 and the second side jet hole 4 and then returns to the ground, so that a large amount of flushing fluid can be prevented from directly eroding a rock core to the maximum extent, the rock core is protected from being eroded, meanwhile, the PDC cutting teeth 5 on the leading bit 1 and the rear bit 2 can be cooled and flushed, particularly the second side jet hole 4 is arranged, the drilling fluid flow of the annular space of the leading bit 1 is obviously improved, and the requirement for timely cleaning the rock powder etched and taken by the leading bit 1 is met; secondly, when a small amount of residual flushing fluid flows to the first step 7, the residual flushing fluid is in contact with the annular buffer groove 8 on the first step to reduce the flow rate, and then positive circulation is formed in the annular space of the pilot bit 1, so that the lubricating effect can be achieved, and the core can be helped to smoothly enter the inner tube of the core; finally, the exit end of the second side orifice 4 outside the leading bit 1 is provided with a spiral guide groove 11 consistent with the direction of rotation of the bit, so that flushing fluid in the annulus of the leading bit 1 can be rapidly discharged from the bottom of the hole, the purpose of rapidly removing the rock powder at the bottom of the hole is achieved, and the rock powder wrapped by the PDC cutting teeth 5 and wrapped by the rock core, which is obtained by the leading bit 1 at any time, is avoided.
It should be noted that in the description of the present invention, terms of orientation or positional relationship such as "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.