FR2492450A1 - ROTARY DRILLING TREPAN FOR DEEP DRILLING - Google Patents

Abstract

THE INVENTION RELATES TO A ROTARY DRILLING TREPAN. THIS TREPAN IS IN THE FORM OF A CONNECTION BODY INCLUDING A THREADED END TO ENSURE THE JUNCTION WITH A DRILL ROD TRAIN OR ANALOGUE DRIVE MECHANISM, THE HEAD OF WHICH IS PROVIDED WITH CUTTING ELEMENTS WHICH EXTEND FROM ITS BASIC ZONE UP TO ITS CENTRAL ZONE AND ARE GROUPS, PROJECTS, IN ROWS OR BANDS AS KNIVES ON ITS EXTERNAL PERIPHERY. THE TREPAN ALSO INCLUDES CUTTING ELEMENTS 6 WHICH EACH TIME SHOW ON A FLAT ATTACK 13 FACE, PLAN VIEW, ONLY CUTTING ELEMENTS 5 AT ATTACK FACE 12 DIVIDED, PLAN VIEW, PARTIAL FACES FORMING AN ANGLE BETWEEN THEM. THE TREPAN IS INTENDED FOR DEEP DRILLING.

Description

The present invention relates to a rotary drill bit for drilling

deep formed of a body

  connecting piece having a threaded end for

  the junction with a drill string or similar drive mechanism, the head of which is provided with cutting elements which extend from its base zone into its central zone and are grouped, projecting, in rows or strips as knives

  on the outer periphery of the bit.

  Such drill bits encounter, during deep drilling in the earth's surface, rock formations of various hardnesses and partly with plastic deformation and are therefore subjected to changing drilling conditions. It has been found that known rotary drill bits with blades which, when viewed in plan, have circular or partly circular sintered diamond cutting elements, do not achieve

  optimum drilling progress in all

  drilling conditions. While in sandy layers

  For example, when such hard drills produce good results, their cutting elements tend, in a soft plastic rock, to be stuffed with their face of attack by accumulating rock debris and then to slide over the layer. rocky without forming chips. The cutting edges then wear out quickly so that the bit is dull for any

  drilling in the rock. For all to form

  skins, it is necessary to exert on the bit as a precaution a very important axial forward force which greatly increases the wear and the necessary torque. On the other hand, there is a rotary drill bit particularly suitable for soft formations which is provided with wedge-shaped cutting elements engaging in formation. The geometry of the section, in particular the leading faces form

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  an acute angle with the cutting direction, allow

  to achieve a charruage effect that ensures better

  their chip formation of the excavated rock for a lower axial force and a lower moment of rotation. The relatively small active area of the cutting elements, however, allows only a small material removal so that the drilling progress of such drill bits, compared to the progression of a bit packed with circular cutting elements or circular part, is substantially

  weaker. The object of the invention is to improve

  a rotary drill bit of the aforementioned type in such a way that drilling progress can be increased in the largest ponrible spectrum of hardness and plasticity of the rock formation,

  taking into account in particular rocks

  ders. This object is achieved by means of the drill bit according to the invention which is characterized in that it comprises both cutting elements which each have only one planar face, plan view, that cutting elements with a divided leading face, plan view, the partial faces forming an angle of less than 1800 between them. Flat-face cutting elements serve to form chips and to remove the rock during the cutting. drilling operation. In hard sandy rock formations, these cutting elements perform most of the cutting work. In softer rocks there is a functional cooperation between the planar face cutting elements and the split face cutting elements which, according to an advantageous embodiment, are offset with respect to their chopped off. The cutting elements with a divided leading face can, because of their higher surface pressure, penetrate into the formation and cut a groove without lateral embankments formed by chips produced. This effect already appears for leading faces whose partial faces form an angle slightly less than 1800. The efficiency improves as the angle between the leading faces decreases. The structural disturbance produced by the penetration into said formation avoids a slip of a block of the rock layer below the cutting edge of the next cutting element which is able to scrape the notched plane of the rock layer by forming chips. In order to cause the formation of chips, the necessary axial advancement force is in this case lower than that

  used for drill bits filled exclusively with

  cuts which have only one tacking face

  that hovers. Wear and torque required

  res are thus also weaker. A drill bit having a combination of said cutting elements makes possible, particularly in soft rocks, a much higher drilling progress than that which can be obtained by using exclusively a bit packed with cutting elements of the one of the two

only kinds.

  To assist the cutting operation and the

  cooling of the cutting elements, nozzles are arranged in front of the groups of cutting elements and the orientation of their jets of rinsing liquid is such that the efficiency of the respective cutting elements is maintained. Since the split-face cutting elements simply have to cut the formation, the dislodged drill chip as by a plow slides laterally between two adjacent cutting elements. This tangential direction is also imposed on the flushing flow of the rinsing liquid discharged by the associated nozzles, which facilitates the longitudinal sliding of the chip at the partial faces of the cutting elements with a divided leading face, which make an angle with the other, and prevents any obstruction of the space provided between the cutting elements. The nozzles disposed in front of the planar face cutting elements subject the flow of rinsing liquid to a radial component so that the chip moving along the leading faces of these cutting elements is discarded. outward and is

  sheared and that cuttings can be removed.

  The leading face of this cutting element can in this case also be arranged at an angle to

  cutting direction, to produce an effect of

ruage oriented outwards.

  While flat-face cutting elements are preferably made of a thin layer of sintered polycrystalline diamond and they

  are fixed each time on a uniform support body.

  supported memento, cutting elements to attack face

  divided may consist of di-

  natural mantle or polycrystalline sintered diamond divided by a cleavage method. The cutting elements are in this case incorporated into the supports

  and are securely anchored.

  Other embodiments of the invention

  clearly from claims 2 to 25 and the

  description of an exemplary embodiment given below.

  after with reference to the accompanying drawings in which: FIG. 1 is a perspective view of a

  rotary drill bit which is equipped with a combination

  season of the cutting elements mentioned above; FIG. 2 is a projection of the cutting plane of a group of cutters with a divided leading face and a group of flat face cutting elements; FIG. 3 illustrates a variant of the embodiment shown in FIG. 2, and FIGS. 4a, 4b, 4c and 5a, 5b, 5c illustrate other possibilities of arrangement of the cutting elements.

  Fig. 1 illustrates a rotary drill bit

  tif comprising a connecting body 1, a threaded end 2 for joining a drill string and a head bearing knives 3, 4. These knives 3 and 4 comprise cutting elements 5 and 6 salient arranged in bands in the form of strips and extend in the form of wall-shaped elevations, radially from the base area of the bit towards its center. In the base area, this elevation is extended over a short axial distance and is provided with a layer of hard material -7 which is impregnated with particles resistant to

  abrasion or which is covered superficially.

  Nozzles 8, 9 are arranged in each recess between the elevations in front of the cutting elements to guide the flow of rinsing liquid and communicate, on the intake side,

  with an inner bore. The nozzles are in

  lower than the cutting elements but the exit cone of the rinsing flow is dimensioned so that all the cutting elements are sufficiently supplied with rinsing liquid. The nozzles 8 associated with the cutting elements 5 have a section

  less transverse than that of the nozzles 9

  The nozzles 8 are oriented in such a way that they impose on the rinsing flow a direction tangential to the drill bit towards the cutting elements 5. The nozzles 9, on the other hand, require the flushing flow, because of their orientation, a radial direction towards the base area of the bit. The cutting elements 6 are formed of thin polycrystalline sintered diamond chips

  and are fixed to hard metal support bodies.

  These bodies are then drowned in. a matrix body

  agglomerated by a binder. The attacking faces of

  5 cutting edges are perpendicular to the direction

  cutting. However, it is also possible to

  apply at an obtuse angle to maintain

  by a slight effect of charruage the evacuation of co-

  skins to the base area of the trephine. The cutting elements 5 are made of natural diamond (cubes) and are embedded in hard metal supports which are

  in turn placed in an agglomerative matrix body

  by a binder. The cutting elements 5 may, however, also be formed by separate sintered diamond bodies. In the cutting direction, each cutting element is delimited by two wedge-shaped surfaces which, during the cutting operation, serve as

  the attack face and, in the cutting plane, it is deli-

  mitted by a pointed surface that serves as a free surface. The three edges formed by the intersection of said surfaces, form cutting edges or cutting edges. The point formed by the junction point

  of the cutting edges and the previous cutting edge

  above exert such a high surface pressure

  on the formation that the cutting elements are

  res to enter the rocky layer. Two

  5 cutting edges are separated by an intermediate space sufficient to allow the passage of the

notch chip.

  The cooperation of the precise cutting elements

  will now be examined with reference to a schematic

  of cut projected in the plane. Such a drawing is

  shown in FIG. 2. The drawing is limited to two cooperating knives comprising the knife 3 carrying cutting elements with a divided leading face * and the cup 4 which in this special case bears

  cutting elements 6 with a flat attack face and

  circular cutting edge. The reference figures

  18 and 19 refer to the cutting insert and the support body, while figures 16 and 17

  designate the cutting element with diagonally

  target and prismatic configuration and its support. The leading faces of the prismatic cutting element are indicated at 12, while the leading face of the circular cutting element is indicated at 13. The cutting lines 10 and 11 which indicate the location of the penetration the deepest cutting elements in the formation, show that the cutting elements are offset staggered. The

  rinsing flow from nozzles

  is shown by arrows 14 and 15. The flushing flow first flows in the opposite direction to

  rotation of the bit, by the intervals

  paranting the prismatic cutting elements 6 and then chan-

  direction and flows outward along

  cutting elements 5 of circular shape. The co-

  scraped skin is shown schematically along the path described by the cutting elements. So

  that the training is simply shattered by the

  prismatic cutters, scraping cleanly

  said is provided by the circular cutting elements.

  In this case, it is obvious that the cutting elements complement each other in the cutting operation and that the rinsing contributes to passing the cuttings

  drilled along the leading faces of the

  cuts and to evacuate them to the outside.

  As a variant of the embodiment shown in FIG. 2, FIG. 3 illustrates

  cutting elements 6 with a flat face

  placed at an angle, and cutting elements 5 with a divided front face 12 whose partial faces form angles slightly smaller than 1800.

  value between 0 and 40 proved to be

  gage for the mounting angle of the cutting elements 6.

  Cooperation between the two genres

  of cutting elements is also obtained with

  Very different arrangements than those shown in FIGS. 1 to 3. Of course, the guide describes the rinsing liquid by selection and orientation of nozzles.

  adequate can no longer be used without more.

  Figs. 4a, 4b and 4c illustrate a combined assembly of the different cutting elements 5, 6 on a knife 20, 21.

  In the assembly of the cutting elements re-

  shown in Figs. 4a and 4c, the training is

  notched by the cutting elements 5 to face attack

  that 12 divided and is scraped by the elements of

  cutter 6 with a front face 13 flat mounted on the cou-

  water 20 which follows in the direction of rotation.

  In the version shown in Fig.4b,

  the scoring and scraping of the formation are

  - Made by the same knife because this knife comprises the two kinds of cutting elements arranged in a manner corresponding to the working sequence namely the cutting elements 6 behind the elements

cutting 5.

  Figs. 5a, 5b and 5c illustrate

  which are formed of a combination of knives 20 or 21, as shown in Figs. 4a, 4b and 4c, with the knives 3 and 4 of Fig.2. The coordination of the cutting elements 5 to the attacking face 12 divided

  and 6 planar attacking face 13 is in this case possible

  when the cutting elements are

  together, either separately on the knives.

  Fig. 6 illustrates a section of radial course in the drilled formation and shows the leading faces of the cutting elements, the cutting elements 5 with divided front face 12 being arranged in front of

  the cutting elements 6 with the leading face 13 plane.

  The distance between the cooperating cutting elements 5, 6 can be chosen so large that the cutting areas

  are adjacent to each other and that the copiousness

  cutting extends into the cutting area of the next cutting element. A certain cutting efficiency is

  however, when the cutting

partially overlap.

  The cutting depth of the divided cutting edge cutting elements 12 can also be

  chosen different from the depth of cut of

  FIG. 6 has a planar front face 13 for optimizing the drilling progress of the bit for a determined plasticity of the formation. The positions

  a, b and c in FIG. 6 illustrate various depths

cutters.

  Fig. 7 illustrates a substantially tangential longitudinal section of a rotary drill bit working in the formation. The illustrated sectional plane follows the line in chain lines shown in FIG. 2. The arrangement of knives, cutting elements and nozzles already described

  with reference to the description of Figs. 1 and 2 will be

  here again specified. In addition the coordination of the cutting elements, mentioned in FIG. 2, is visible from a lateral perspective to the direction

cutting.

  Fig. 8 illustrates the correlation of

  The following pressures are used herein: "planar face" 13 and "divided leading face" 12 and shows the angle formed between the partial faces

  of the divided attack face 12 which must be less than

at 1800.

1 C?

Claims (19)

R E V E N D I C A T I 0 N S   1 - Drill bit for deep drilling, formed of a connecting body having a threaded end for joining a drill string or a similar drive mechanism, the head of which is provided with elements which extend from its base zone to its central zone and are grouped, projecting, in   rows or in strips as knives on the peri-   outer periphery of the bit, characterized in that   also carries cutting elements (6) which do not   feel each time that a leading face (13) plane, seen in plan, that cutting elements (5) to face   of attack (12) divided, seen in plan, the partial faces   forming between them an angle of less than 180 (Fig.8).   2 - rotary drill bit according to claim 1, characterized in that each knife (20,21) comprising cutting elements (6) with a planar face of attack (13), in plan view, and cutting elements ( 5) with a divided leading face (12), in plan view, the partial faces forming between them an angle of less than 180 (Fig. 4a, b, c). 3 - rotary drill bit according to claim 2, characterized in that on each   knife (20,21) are arranged alternately   cutting elements (6) with planar leading face (13), seen   in plan, and cutting elements (5) with   t12) divided, plan view, which is staggered   dialement from the base area to the central area.   Rotary drill bit according to Claim 3, characterized in that the two types of cutting elements (5, 6) are arranged side by side. side by side (Fig. 4a).   5 - rotary drill bit according to claim 3, characterized in that the cutting elements (5) with a divided leading face (12 are angularly offset with respect to the elements of FIG.   cutting (6) flat front face (13).   6 - Rotary drill bit according to   claim 3 or 5, characterized in that the elements   cutting elements (5) with a divided leading face (12) are arranged in the direction of rotation of the bit in front of the cutting elements (6) with a leading face plane (13) (Fig. 4b).   7 - Rotary drill bit according to   claim 3 or 5, characterized in that the elements   cutting elements (5) with a divided leading face (12) are arranged, in the direction of rotation of the bit, behind the cutting elements (6) with a leading face plane (13) (Fig. 4c).   8 - Rotary drill bit according to   claim 4 or 6, characterized in that the elements   The cutting elements are radially offset in their cutting lines from similar cutting elements on adjacent knives (Fig. 4a and Figs. 4b).   9 - rotary drill bit according to claim 7, characterized in that the cutting elements are arranged radially in line, as for their cutting lines, with similar cutting elements located on adjacent knives (Fig.4c). - rotary drill bit according to claim 1, characterized in that alternately, a knife (4) comprises cutting elements (6) with planar face of attack (13), seen in plan, and a neighboring knife   (3) has cutting elements (5) with   plate (12) divided, plan view, the partial faces forming an angle of less than 180 (Fig 1, 2,3).   11 - rotary drill bit according to claim 10, characterized in that cutting elements (6) with a planar face of attack (13), seen in plan, are   offset, as to the cutting lines (11) that they de-   write, relative to the cutting lines (10),   cutting elements (5) with a divided leading face (12), seen in plan.   12 - rotary drill bit according to claim 1, characterized in that it comprises knives (4) provided with cutting elements (6) with planar face of attack (13), seen in plan, knives (3). ) provided with cutting elements (5) with a divided leading face, in plan view, and knives (20, 21) provided with   cutting elements (5,6) of both types (Fig. 5a, 5b, 5c).   Rotary drill bit according to Claim 12, characterized in that the cutting elements (5) with a divided leading face (12) are arranged on the common knife (20, 21) in front of or behind the cutting elements ( 6) with the flat face (13) in the direction of rotation of the bit, and the knives (3, 4) comprising only cutting elements (5, 6) with a divided leading face (12). or   flat face (13) have the same success.   with regard to the arrangement of cutting elements (5,6) in the direction of rotation (Fig. 5b, 5c).   14 - rotary drill bit according to claim 12, characterized in that the cutting elements (5, 6) with a divided leading face (12) and a planar leading face (13) are arranged side by side on the common knife (20 or 21) and knives (3; 4)   which bear only cut-to-face cutters   plate (13) flat or divided face (14) divided,   are arranged in a succession that can be chosen   sie. but who is homogeneous, behind the common knife (20 or 21) (Fig. 5a).   - Rotary drill bit according to one   any of claims 3 to 10 or 12, 13,   characterized in that cutting elements (6) having a planar, planar facing face (13) are adjacent, by their cutting zone, to the cutting zone of cutters (5) with attack (12) divided, plan view, which precedes in the direction of rotation and which are   neighbors in the radial direction or extend into that   this. 16 - Rotary drill bit according to one   any of claims 1 to 15, characterized in   the cutting elements (6) with a planar face (13) planar face have contour cutting edges   ellipsoidal or partly ellipsoidal.   17 - Rotary drill bit according to one   any of claims 1 to 15, characterized in   the cutting elements (6) with the leading face (13) plane, in plan view, have cutting edges at their   circular or partly circular contour.   18 - Rotary drill bit according to one   any of claims 1 to 15, characterized in   the cutting elements (5) having a leading face (12) which are divided in plan view have partial faces (12) forming acute angles between them; of the cup.   19 - Rotary drill bit according to one   any of claims 1 to 15, characterized in   the cutting elements (5) with the leading face (12)   divided, plan view, have a prismatic outline.   - Rotary drill bit according to one   any of claims 1 to 19, characterized in   in that the cutting elements (5) with a divided front surface (12) are calibrated for a greater cutting depth than the cutting elements (6).   flat face (13), plan view (Fig. 6c).   21 - Rotary drill bit according to one   any of claims 1 to 19, characterized in   the cutting elements (5) with the divided front face (12), in plan view, are calibrated for very plastic or moderately hard rock formations and for a smaller cutting depth than the cutting elements (6). ) flat face (13), view in plan (Fig. 6a).   Rotary drill bit according to Claim 17, characterized in that the cutting elements (6) consist of a polycrystalline sintered diamond layer (18) which is fastened to support (19).   Rotary drill bit according to Claim 18 or 19, characterized in that the cutting elements (5) consist of natural diamonds (16) or prismatic sectors of a polycrystalline sintered body and the sintered bodies or diamonds are their part in support bodies * (17).   24 - rotary drill bit according to claim 10 or 11, characterized in that nozzles (8,9) for the rinsing liquid are provided in front of the knives (3,4), in the direction of rotation of the   bit and communicate with a central bore in the   inside the bit, the outlets of the   tages (8) associated with the cutting elements (5) with the divided front face (12), in plan view, being oriented and   provided in such a way that a direct component   essentially tangential (14)   to the rinsing jets in the opposite direction to the rotation of the bit and the nozzle outlets (9) associated with the plane-facing leading-edge cutting elements (6) being oriented and in that a substantially outwardly directed radial component (15) is imposed   to the jets of rinsing liquid (Fig. 1,2,3).   Rotary drill bit according to claim 24, characterized in that the cross-sectional area of the nozzles (8) associated with the cut-off cutting elements (12) divided in plan view is smaller than that of the nozzles (9). ) associated with   cutting elements with flat face (13) plane view (Fig.l).