A kind of tooth cave fluid erosion prevention steel body PDC drill bit
Technical field
The present invention relates to a kind of tooth cave fluid erosion prevention steel body PDC drill bit for oil and geological drilling field, belong to petroleum geology drilling tool technical field.
Technical background
Steel body PDC drill bit is when long-time use or when shaft bottom mud sand content is heavier, near nozzle, the tooth cave of position is easily by erosion.The appearance of this situation, the wall shear stress mainly suffered by erosion position is comparatively large, and this place's protective capacities relative deficiency.Position, existing steel body PDC Cutter tooth cave cover weldering thickness be 1.5 ~ 2mm, often easily there is the drill bit initial failure problem because bit teeth cave is caused by erosion.Application life the requirement of Oil Field to steel body PDC drill bit can grow, and can repeatedly repair.Therefore, must ensure that drill bit does not occur erosion, to extend the application life of drill bit when long-time use.But existing steel body PDC drill bit fluid erosion prevention structure still difficulty meets above-mentioned instructions for use.
Namely on the other hand, after the wing of existing PDC drill bit, the outer surface of wing is flat face, also namely after wing with wing before angle be 90 ° or be slightly less than 90 °.When drilling bit high-speed creeps into, because drill bit is that spiral moves downward, after cutter breaking rock, the landwaste amount that the nose of drill bit wing and shoulder produce is more, has certain delay after tooth, thus the talus deposit below of formation wing, talus deposit not only can limit the degree of depth on the wedging stratum of Cutter, after worn drill bit wing, and can increase drill bit creep into resistance, thus limit the further raising of drill bit rate of penetration, reduce drilling life of bit.
Summary of the invention
Technical problem to be solved by this invention is that the deficiency existed for above-mentioned prior art provides a kind of tooth cave fluid erosion prevention steel body PDC drill bit.
The technical scheme that the problem that the present invention is the above-mentioned proposition of solution adopts is: comprise bit body and wing, the front and back surfacing wearing layer of wing, before wing, top offers tooth cave, composite sheet cutting teeth is installed in tooth cave, it is characterized in that at edge cave, front end edge tooth cave, tooth cave groove, surfacing wearing layer in the groove of cave.
By such scheme, described tooth cave is semi arch hole or more than half circular hole, and the described cave groove along tooth cave edge is that radius of curvature is greater than the half-arc groove of tooth cave arc radius or more than half arc groove.
By such scheme, described cave groove axial depth is 2 ~ 6mm, and described cave groove radial depth is 2 ~ 6mm.
By such scheme, before described wing, the wearing layer thickness of surfacing is 1 ~ 2 mm, cover weldering thickness from top to bottom gradient successively decrease.
By such scheme, after described wing, the wearing layer bending of surfacing extends to the wing back side, and thickness is 1 ~ 2 mm, successively decreases from front to back.
By such scheme, be gauge section above the shoulder of described wing, at gauge section inclined-plane surfacing wearing layer.
By such scheme, described gauge section inclined-plane offers pit or groove, surfacing wearing layer in pit or groove.
By such scheme, the nose of wing and/or shoulder below namely outer surface arrange intilted domatic.
By such scheme, 2 ~ 6mm bottom described intilted domatic section start distance composite sheet cutting teeth tooth cave, extands rearward to the wing back side from section start.
By such scheme, described intilted domatic lowest part and the vertical distance of section start are more than or equal to 4mm.
By such scheme, described intilted domatic two is domatic by transition to be connected mutually with the planar back front of wing remainder.
By such scheme, described wearing layer is tungsten carbide of nickel-base wearing layer or iron-based tungsten carbide wear resistant layer.
Beneficial effect of the present invention is: the erosion resistance 1, enhancing front portion, tooth cave, thus extends the application life of steel body PDC drill bit, 2, by the increase of local surfacing material around tooth cave and the thickness-tapered of wearing layer, the surface consolidation material that weldering is relatively many can be covered around tooth cave, the wearing layer around tooth cave is made to obtain more reasonably distributing, under the prerequisite of strengthening tooth cave fluid erosion prevention performance, the consumption that entirety covers wlding material can be reduced, reduce drill bit processing cost, 3, at the wear-resisting surfacing layer of gauge section inclined-plane surfacing, enhance PDC bit gauge protection inclined-plane abrasive resistance, in long frequently short the operation of directional drilling, effectively can reduce the wearing and tearing on gauge section inclined-plane, thus avoid directional well steel body PDC drill bit to cause drill bit to lose efficacy because gauge section loses efficacy in advance, therefore the drilling footage of single directional well steel body PDC drill bit improves 10% ~ 25%, thus extends drilling life of bit, and on gauge section inclined-plane, offer pit and groove can make wear-resisting surfacing layer be engaged more firm with gauge section inclined-plane, the gauge section inclined-plane of more effective protection steel body PDC drill bit, 4, by intilted domatic arranging below of the more wing nose of landwaste amount and shoulder, not only increase drill bit nose, the cleaning of shoulder cutting teeth and cooling, fast the landwaste creeping into generation is drained, and effectively can reduce landwaste and produce after wing and between face, shaft bottom and interfere, that reduces drill bit creeps into resistance, improve the efficiency of breaking rock of drill bit, thus improve the rate of penetration of drill bit, extend the application life of drill bit, keep flat face constant after the inner cone few to landwaste amount and the wing of other parts, ensure that the contact area in inner cone and other parts and shaft bottom, thus ensure that the stability that drill bit creeps into.
Accompanying drawing explanation
Fig. 1 is the partial sectional view of the tooth cave part of one embodiment of the invention.
Fig. 2 be one embodiment of the invention wing part before the distribution schematic diagram of surfacing wearing layer.
Fig. 3 is the three-dimensional structure diagram of one embodiment of the invention.
Fig. 4 is the three-dimensional structure diagram of second embodiment of the invention.
Fig. 5 is the partial view of gauge section chamfered portion in second embodiment of the invention.
Fig. 6 is the partial view of the another kind of structure of gauge section chamfered portion in second embodiment of the invention.
Fig. 7 is the three-dimensional structure diagram of third embodiment of the invention.
Fig. 8 is the plan structure figure of Fig. 7.
Fig. 9 is the A-A sectional view in Fig. 8.
Detailed description of the invention
Below in conjunction with accompanying drawing, the present invention is further illustrated.
First embodiment as shown in Figure 1, 2, 3, comprise bit body 10 and interval is installed in bit body periphery and end face bent wing 4 outwardly, be chip area between wing, in chip area, be provided with nozzle 5, before wing, tooth cave is offered in top, described tooth cave is more than half circular hole, and at edge cave, front end edge tooth cave, tooth cave groove, the radius of curvature of cave groove is greater than tooth cave arc radius, for more than half arc groove, cave groove axial depth is 3mm, and radial depth is 4mm, surfacing wearing layer 6 in the groove of cave.Described tooth cave is spaced along outline before wing and installs, and is distributed in the interior tapering of wing, nose, shoulder and gauge section, is installed on columned composite sheet cutting teeth 1 in tooth cave; The equal surfacing wearing layer in the front and back of wing, before described wing wearing layer 2 thickness of surfacing from top to bottom gradient successively decrease, wherein the first half front region 7 wearing layer thickness in nearly tooth cave is thicker is 2 ~ 1.5mm, and the wearing layer thickness-tapered of the latter half front region 8 is 1.5 ~ 1mm; The wearing layer surfacing of the wearing layer before wing and cave groove is integral.After described wing, the wearing layer bending of surfacing extends to the wing back side, and thickness successively decreases from front to back, is progressively decremented to 1mm by 2 mm thickness.In drill bit process, first tooth cave structure is processed, adopt graphite to be bonded at tooth acupuncture point for sheet in the position that composite sheet is corresponding and put, then carry out surfacing with surfacing high-abrasive material by the surfacing structure shown in Fig. 1, Fig. 2.Wherein the surfacing wearing layer thickness of cave groove peripheral region is the thickest, and secondly, the surfacing wearing layer thickness leaving peripheral region, tooth cave is the thinnest, and the material of surperficial surfacing is tungsten carbide of nickel-base for the surfacing wearing layer thickness near peripheral region, tooth cave.
Drill bit and other downhole tool couple together, together at the bottom of lower going-into-well, and then turn on pump circulating fluid rotary drilling of pressurizeing.Around tooth cave, namely the drilling fluid impact force suffered by surfacing region around tooth cave is maximum, also be the position the most easily producing erosion inefficacy, it is the thickest that weldering thickness is covered at this place, thus erosion resistance is stronger, and reduce in the impact force gradient that all the other surfacing region drilling fluids produce, it covers weldering thickness, and also corresponding gradient is thinning.Thus reach the erosion resistance enhancing front portion, tooth cave, thus extend the application life of corresponding drill bit.Meanwhile, due to the change of surfacing layer thickness gradient, decrease the use of surface consolidation material, reduce the processing cost of drill bit.
Second embodiment as shown in Figure 4,5, 6, it is gauge section above the shoulder of wing, the upper end of gauge section is gauge section inclined-plane 9, described gauge section inclined-plane major part surfacing wear-resistant material layer is with the difference of a upper embodiment, wear-resistant material layer is iron-based tungsten carbide surfacing layer, and the wear-resistant material layer of surfacing flushes with the gauge section inclined-plane of non-surfacing.Can offer flat pit on gauge section inclined-plane, flat pit is offered along chamfered edge edge, surfacing wear-resistant material layer in flat pit.Or on gauge section inclined-plane, offer longitudinal straight trough along interval, inclined-plane, surfacing wear-resistant material layer in longitudinal straight trough.High-abrasive material layer height is concordant with face that inclined-plane stays.
3rd embodiment is as Fig. 7, 8, shown in 9, tooth cave is offered before wing, the composite sheet cutting teeth 1 of cylinder bulk is installed in tooth cave, composite sheet cutting teeth is spaced along wing outline and installs, be distributed in the interior tapering 11 of wing, nose 12 and shoulder 13 etc., difference be the nose of wing and shoulder namely the nose of the outer surface of wing and shoulder arrange intilted domatic below, spacing a bottom described intilted domatic section start and composite sheet cutting teeth tooth cave is 2.3mm, domaticly extand rearward to the wing back side 14 from section start, domatic lowest part (with the intersection at the back side) is 24.5mm with the vertical distance b of section start.Described intilted domatic two is connected with after wing remainder mutually by transition is domatic, is flat face after wing remainder.
In drilling process, when cutting teeth wedging stratum, its landwaste produced at wing inside cone part is detained after wing, but because its landwaste amount is relatively less and cutting teeth has suitable high grinningly, therefore it does not have an impact to the rate of penetration of PDC drill bit; The landwaste produced at wing nose, shoulder is relatively many, but be introversion slope structure after wing, this slope structure can effectively by Cutting movement to chip area, thus prevent the interference that landwaste moves downward drill bit, decrease landwaste to the wearing and tearing in drill bit wing back face and frictional resistance, and then improve the rate of penetration of drill bit, extend drilling life of bit.