RU2086750C1 - Annular milling cutter - Google Patents

Abstract

FIELD: oil and gas production industry. SUBSTANCE: this is used for repair and restoration of emergency objects. Inner surface of milling cutter body has slots which are perpendicular and parallel to longitudinal axis of cutter body. Located in lower part of longitudinal slots are supporting inserts which are rigidly connected to body. Attached to supporting inserts is cutting-grinding member. Made in outer surface of body are longitudinal side slots with widening upper part. Made in lower end face of body are radial flushing passages. This arrangement of annular milling cutter ensures efficient flushing at milling of emergency objects, allows for creation of solid body which adds to reliability and service life. EFFECT: high efficiency. 2 cl, 4 dwg

Description

 The invention relates to the oil and gas industry and is intended for the restoration and repair of wells by milling emergency facilities.

 Known milling machine containing a housing, under the bottom of which a destructive element of a cutting-abrasive type is installed [1] However, this milling cutter has a low penetration value and is not reliable enough in operation.

 The closest set of features to the claimed device is an annular milling cutter, comprising a housing with a connecting thread, a cutting-abrasive element and flushing channels at the lower end and grooves on the inner and outer surfaces of the housing [2] This design, however, also does not provide the necessary penetration and reliability due to inefficient flushing during milling of emergency objects, which leads to jamming of the tool, and insufficient strength of the case.

 The objective of the invention is to increase the reliability and magnitude of penetration.

 This problem is solved due to the fact that, in contrast to the above-mentioned ring milling cutter in the proposed design, the grooves on the inner surface of the housing are parallel and perpendicular to its axis, and in the lower part of the longitudinal grooves there are support inserts rigidly connected to the housing, on which cutting-abrasive is fixed element, and lateral longitudinal grooves on the outer surface of the housing are made with an expanding upper part.

 In this case, the longitudinal side grooves on the outer surface of the housing can be made inclined to its generatrix, and the end flushing radial channels can be made curved.

 The technical result of the invention lies in the fact that the implementation of the grooves on the inner surface of the mill body increases the washing efficiency by the proposed method, ensures turbulence of flow and cavitation, improves the removal of chips outside, thereby preventing the buildup of fracture products on the cutting part and jamming of the tool.

 In addition, the edges of these grooves facilitate milling of the emergency object from the outside, increase the speed of penetration. The implementation of the outer side grooves with an expanding upper part also facilitates the removal of chips, cement, rock destroyed by flushing fluid. The fastening of the cutting-abrasive element on the support inserts located in the lower part of the longitudinal grooves on the inner surface of the housing, provides the creation of a monolithic housing, simplifies the technology of creating longitudinal grooves on the inner surface. In the case of performing longitudinal grooves on the outer surface of the housing inclined, the cutting conditions are improved, the working life of the milling cutter increases, and its operational reliability increases.

 Performing end flushing radial channels curved also improves the cutting conditions, makes it smooth, shockless, thereby increasing the cutting speed and durability of the milling cutter.

 In FIG. 1 shows a ring milling cutter in longitudinal section, FIG. 2 is a view A of FIG. 1, FIG. 3 is a view B of FIG. 1, and FIG. 4 is a view B of FIG. 1.

 The milling cutter includes a housing 1 with a cutting abrasive element 2 at the lower end and a connecting thread 3. On the inner surface of the housing 1, grooves 4 are made parallel to the axis of the housing 1 and grooves 5 are perpendicular to the axis of the housing. Support inserts 6 are placed in the lower part of the grooves 4, rigidly associated with the housing 1, for example, by soldering or welding.

 Insert 6 is a structural element that repeats and complements the internal and external forms of the housing 1, made of a hard alloy, for example, type VK. Element 2 is fixed on the inserts 6, as on the end of the housing.

 On the outer surface of the housing 1 there are longitudinal grooves 7 with an expanding upper part 8 (Fig. 3) and radial flushing end channels 9 (Fig. 4).

 Ring mill works as follows. The milling cutter is lowered on the drill string to the emergency stuck pipe (drill, pump-compressor, sucker rod or round object), capturing and passing it inside. Using the drill string rotate the milling cutter, creating an axial force on the milling cutter towards the emergency string. The milling cutter element 2 drills the rock and foreign metal objects around the emergency pipe and at the same time drills the emergency pipe. In this case, the internal teeth (protrusions), which are formed by longitudinal 4 and annular 5 grooves, remove adhering sludge or a part of metal from the outer surface of the emergency pipe, creating a predetermined size of the external diameter of the emergency pipe for subsequent capture by a fishing tool. When milling the emergency pipe, flushing fluid is pumped through the internal cavity of the milling cutter. With the passage of fluid through the annular grooves 5, cavitation occurs. When the bursting of air bubbles on the cutting surfaces of the cutting element 2 from micro-impacts, these surfaces are cleaned of adhering chips and improve the cutting process. Shavings and sludge are carried out through the end channels 9 and the outer longitudinal grooves 7 from the bottom up.

 Upon reaching expansion 8 in the outer longitudinal groove 7, the solution with chips and sludge spreads in the expansion cavity and leaves it up into the space between the body and the casing. Due to the expansion of 8 facilitates the exit of the solution with the sludge up.

 Milling is carried out to a predetermined depth necessary to capture the fishing tool. After that, the router is lifted to the day surface.

Claims (3)

 1. An annular milling machine comprising a housing with a connecting thread, a cutting-abrasive element, flushing radial channels at the lower end and grooves on the inner and outer surfaces of the housing, characterized in that the grooves on the inner surface of the housing are parallel and perpendicular to its longitudinal axis, and The lower part of the longitudinal grooves contains support inserts rigidly connected to the housing, on which a cutting-abrasive element is fixed, and the lateral longitudinal grooves on the outer surface of the housing are made with wide yayuscheysya top.  2. The milling cutter according to claim 1, characterized in that the lateral longitudinal grooves on the outer surface of the housing are made inclined to its generatrix.  3. The milling cutter according to claim 1, characterized in that the flushing radial channels at the lower end of the housing are made curved.

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