RU2244797C1 - Drill bit - Google Patents

Abstract

FIELD: rock crushing tools; methods of fitting ejection hydraulic giant tips for erosion breaking of rock by sludge pulp.

SUBSTANCE: proposed drill bit has body with connecting thread, rock rollers mounted on trunnions of lugs at inclination relative to longitudinal axis of drill bit by means of bearings; drill bit is also provided with sintered-carbide ejection type hydraulic giant tips which are brought to face at distance δ equal to three or four calibrated diameter of tip but not below depth of rock roller tooth; they are located in washing passages of drill bit by the following scheme: first - by radius over drill bit periphery at angle of inclination to longitudinal axis of drill bit of 5-7 deg.; second - in center of drill bit radius and third - in center at shift of axis of ejection hydraulic giant tip relative to longitudinal axis of drill bit by magnitude "a" of calibrated diameter of tip.

EFFECT: increased mechanical speed of drilling; enhanced operational efficiency.

5 dwg

Description

The invention relates to a rock cutting tool, and in particular to a installation scheme for ejection-hydromonitor nozzles providing erosive destruction of rocks by slurry pulp.

Known drill bits with various patterns of placement of hydraulic nozzles (Kirillin V.I. Choice and optimization of flushing devices for roller cone bits. - VNIIOENG, 1991. - 126 p .; Makarov N.G. Analysis of improvement of flushing systems for cone bits / N.G. .Makarov, V.Ya. Yasashin, D.Yu. Serikov // NTZh. Construction of oil and gas wells on land and at sea. - VNIIOENG. - 2001. - Issue 12, - S.6-10).

Known layout of hydraulic nozzles:

- asymmetric flushing;

- use of the ejection effect;

- equipping bits with vortex chambers;

- the use of pulsating flushing;

- the use of nozzles of reduced diameter with their approach to the bottom.

A bit is known in which one nozzle with a large cross section of the outlet channel is used, for the placement of which the axes of two trunnions are displaced to the third trunnion, and the nozzle is placed between the offset trunnions forming an expanded opening. In this case, the drilling fluid is brought to the bottom and moves along it to openings free of nozzles (A.S. 625015 USSR, MKI E 21 B 10/18).

The disadvantage of such a layout for flushing nozzles is a single point, only in the center, the defeat of the face.

A bit is known in which, for better removal of sludge from the annulus, the paws of the bit are made with channels communicating the suprahepatic cavity with the annulus. The ejection channel is connected to the body cavity by means of a nozzle or ejection nozzle formed by two concentrically mounted bushings fixed in the chisel paw. The annular cavity between the bushings forms an ejection channel in communication with the cavity of the bit through the hole. Drilling fluid supplied to the nozzle from the nipple part of the bit creates an ejection effect in the channel of the paw of the bit, which improves the removal of sludge from the suprahear zone (AS 599031 USSR, MKI E 21 B 10/18).

The efficiency of the removal of sludge from these bits is insufficient, due to the low efficiency of the ejection nozzle of an imperfect design. In addition, this nozzle is removed from the surface of the face and is directed upstream of the solution and cannot realize the erosion effect.

Known ejection-hydromonitor nozzles made in a single housing with a mixing chamber and a diffusion-accelerating tube, providing erosive destruction of the rock by sucking up slurry pulp, accelerating it to the velocity of the jet and creating hydraulic shock at the bottom (patent RU 2117746).

The placement of ejection-hydromonitor nozzles on the bit according to well-known schemes, for example, symmetrical, with the nozzles located on the periphery above the cone teeth does not provide erosive destruction of the rock by a stream of sludge pulp over the entire surface of the face due to their peripheral location, the absence of openings between the cone teeth, significant removal (120-150 mm) the ends of the nozzles from the face surface, as a result of which the jet effectively cleans the peripheral row of cone teeth, but does not reach and does not destroy the rock, making cleaning difficult tny teeth, an exit of a stream of solution and removal of the cuttings from under a bit.

Known technical solutions do not provide for the destruction of the rock by slurry pulp during drilling with cone and other types of bits due to the design features of hydraulic nozzles and schemes for their placement in the bit.

In all cases, when placing the hydraulic nozzles in the bit, an intensive cleaning of the bottom and near-hammer space from drill cuttings is provided, including through ejection of the stream using ejection nozzles directed upward from the bottom. The erosion effect partially occurs when installing elongated nozzles at a high flow rate, while the abrasive properties of the cuttings are not used.

Closest to the proposed solution is a three-cone drill bit containing a cylindrical body with a connecting thread at one end and pins at the other, obliquely located to the longitudinal axis of the bit, on which are mounted bearings with carbide teeth equipped with three hydromonitor carbide or ceramic-ceramic nozzles fixed in the washing channels of the housing by means of a locking element. Nozzles are placed in the openings between the cones and symmetrically located relative to the cones.

A feature of the bit is the installation of nozzles at an acute angle to the longitudinal axis of the bit in the direction of rotation and at the same time tangentially to the walls of the well and calibrating carbide teeth in front of the cone. After reflection from the borehole wall, the flow rate of the flushing fluid is also tangentially directed in the transverse direction along the face surface (US Pat. SU 5029656 USA, IPC E 21 B 10/18).

The disadvantages include the symmetrical arrangement of nozzles, the jet of which affects the face only along the periphery of the bit, and the angle of their inclination provides only cleaning of the cone teeth and the peripheral part of the face, which does not allow using the erosion-hydromonitor effect to destroy the rock on the face surface.

The technical task of the invention is to increase the mechanical drilling speed and efficiency of the bit due to the effective erosion-hydromonitor rock destruction by slurry pulp, cleaning the bottom and cone teeth from slurry pulp reflected from the bottom by a fluid stream, reducing the contact area between the bit and the rock, eliminating the oppressive differential pressure, acceleration of adsorption softening of the rock.

This goal is achieved by the fact that in the drill bit containing the body with connecting thread, cones mounted on the pivot pins obliquely to the longitudinal axis of the bit by bearings, carbide-tipped hydraulic monitor nozzles are made ejection and close to the bottom by a distance δ equal to three or four calibrated nozzle diameters , but not lower than the height of the adjacent tooth cone, and placed in the flushing channels of the bit according to the scheme: the first - along the radius on the periphery of the bit with an angle of 5-7 ° to the longitudinal axis of the bit, W the sharp one is in the middle of the bit radius, the third is in the center, with the axis of the ejection jetting nozzle offset relative to the longitudinal axis of the bit by a value of the calibrated nozzle diameter.

An increase in the mechanical drilling speed and the efficiency of the bit is achieved by changing the surface of the face as a result of erosive destruction of the rock by a jet of liquid containing sludge pulp and the formation of annular recesses.

Figure 1 shows the drill bit along section AA, figure 2 is a bottom view. In Fig.3-4, the operation diagram of the hydraulic nozzles in the well, located according to the proposed scheme. 5, the leader of FIG. 3.

The three-cone drill bit contains a body 1, cones 2, ejection-hydromonitor nozzles: 3 - peripheral, 4 - intermediate, 5 - central, which are placed in the flushing channels of the bit according to the scheme: along the radius on the periphery of the bit with an angle of inclination of 5-7 ° to the longitudinal the axis of the bit (3), in the middle of the radius of the bit (4), in the center, with the axis of the ejection-hydromonitor nozzle offset relative to the axis of the bit by the value of the calibrated nozzle diameter a = d _n (5), so that their ends are separated from the bottom surface (10 ) (Fig. 4) at a distance δ equal to three to four ibrovannym nozzle diameters (Figure 1). During the washing process, when liquid flows out of the calibrated nozzle opening, a vacuum space arises in which a solution saturated with slurry pulp is sucked through the side openings in the nozzle body 7. The slurry pulp (7) accelerates to the velocity of the jet, acquiring a tremendous dynamic force up to 14 times strength without sludge. Microshocks of the sludge intensively destroy the rock, creating recesses, an annular recess (9) and pillars of the rock (8) during the rotation of the bit (figure 3).

As a result, the area of contact of the bit with the surface of the face (10) (Fig. 4) decreases by 30-40%, and on the lateral surface of the pillar (8), the bottomhole pressure P 3 _is reoriented from the vertical depressant to the horizontal bedding rocks in the plane of formation pressure P _pl .

Since P _{s is} greater than P _pl , then under the difference ΔP = P _s -P _{pl the} pressure in the whole (8) will equalize to P _s . Thus, the inhibitory pressure ΔP will be neutralized. Under the pressure drop ΔР, the solution filtrate will penetrate faster into the pillar (8) by bedding, wedging the layers (11) and creating favorable conditions for absorption softening (Fig. 3).

The cone teeth are cleaned at three points along the radius on the periphery (3), in the middle (4) and at the top of the cones (5) with a solution jet reflected from the bottom at an angle of 120 ° (Fig. 3). At the same time, part of the solution flow and slurry pulp (7) are removed from under the bit, heading into openings between cones (2) free from nozzles, and the other, together with slurry pulp (7), is ejected into nozzles (3, 4, 5) and with high speed, the jet is directed to the surface of the face (10).

In aggregate, this creates the conditions for intensive destruction of the rock throughout the face and growth of 2-3 times the mechanical drilling speed.

Claims (1)

A drill bit containing a body with a connecting thread, cones mounted on the pivot pins obliquely to the longitudinal axis of the bit by means of bearings, hard-alloy hydraulic nozzles, characterized in that the hydraulic nozzles are ejected and close to the bottom by a distance δ equal to three or four calibrated nozzle diameters , but not lower than the height of the adjacent tooth cone, and placed in the flushing channels of the bit according to the scheme: the first - along the radius on the periphery of the bit with an angle of inclination of 5-7 ° to the longitudinal axis of the bit from, the second - in the middle of the bit radius, the third - in the center, with the axis of the ejector jet nozzle offset relative to the longitudinal axis of the bit by the value α of the calibrated nozzle diameter.

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