A long-life composite drill bit for repairing damaged casing wells

Abstract

The invention relates to a long-service-life composite drill bit for repairing a casing damaged well. The long-service-life composite drill bit for repairing the casing damaged well is mainly composedof a plurality of rows of teeth, a rolling and sliding composite bearing, a sealing combination, a tooth palm body, a water hole and the like. The lower portion of the rolling and sliding composite bearing adopts a hollow roller structure, and the rolling and sliding composite bearing has the high heat dissipation capability, and can operate at a high speed. A rubber slide block is low in abrasion speed, and reduction of the contact pressure on a shaft neck is facilitated. The sealing combination has the advantages that rotary sealing, axial and radial sealing are achieved. The rolling and sliding composite bearing can bear the high revolution speed and high load, and has a high impact resistant property, and thus the bearing service life of the composite drill bit under the conditions ofthe high revolution speed and the medium and high drilling pressure is ensured. The revolution speed of the composite drill bit is increased, and the rotary sealing and axial and radial sealing effects are outstanding. The service life of the bearing under the dynamic load is longer than that under the maximal loading capacity, compared with a homogeneous composite drill bit for well repairing, the rubber slide block is arranged, and thus the bearing is prevented from being rapidly abraded.

Description

technical field [0001] The invention relates to the technical field of drilling equipment, in particular to a long-life composite drill bit for repairing damaged casing wells. Background technique [0002] At present, the production of many oil wells in China has entered the middle and late stages. Due to the long-term extrusion of the casing and the erosion of the fluid medium, especially the application of some stimulation measures such as gas injection, water injection, acid fracturing, and steam huff and puff, the growth of the casing has been accelerated. Damage: phenomena such as casing shrinkage and deformation, casing rupture or casing dislocation seriously affect the normal production of oil and water wells. When the casing is seriously deformed, broken or broken, the conventional milling tools such as grinding shoes and milling cones often have the phenomenon of grinding out the casing, which increases the difficulty of the next step of construction, and seriously ...

AI Technical Summary

Problems solved by technology

[0002] At present, the production of many oil wells in China has entered the middle and late stages. Due to the long-term extrusion of the casing and the erosion of the fluid medium, especially the application of some stimulation measures such as gas injection, water injection, acid fracturing, and steam huff and puff, the growth of the casing has been accelerated. Damage: phenomena such as casing shrinkage and deformation, casing rupture or casing dislocation have seriously affected the normal production of oil and water wells

When the casing is seriously deformed, broken or broken, the conventional milling tools such as grinding shoes and milling cones often have the phenomenon of grinding out the casing, which increases the difficulty of the next step of construction, and seriously causes oil and water wells to be damaged. Scrapped, seriously delayed the workover period, increased workover costs, and affected crude oil production

The casing is deformed, broken, or even disconnected. Although it is easy to open the window and form the outer channel of the casing when grinding and milling with grinding shoes, the grinding and milling tools have the disadvantages of insufficient strength and few grinding and milling points, which may easily cause major accidents in the drill sticking project, and The curved casing is a section of deformation. It is easy to mill off a large area of ​​the casing, causing the well wall to collapse. The normal circulation washing can not be built, resulting in the failure of the workover. To solve the existing problems, it is necessary to carry out milling tools, milling processes and Study on Temporary Sand Control Technology

[0003] For the structural design and process manufacturing of milling tools such as milling cones and milling shoes, multi-edged flat-bottomed milling shoes are used for casing damage well operations, which are easy to hit, wear fast, and have a short service life, increasing the number of tripping operations. Greatly reduced work efficiency

[0004] The above existing compound drill bits for well workover have the following problems: sliding bearings cannot withstand high speed, and rolling bearings are difficult to withstand high workover drilling pressure, so the bearing life is significantly reduced; The impact received is relatively significantly increased, and the lateral and longitudinal vibrations of the drill bit are more serious, so the teeth wear quickly, and the teeth are prone to breakage, thereby reducing the drilling efficiency. Similar to conventional milling tools such as milling cones and grinding shoes, conventional workover It is also inevitable that the drill bit will rub against the inner wall of the casing and damage the inner wall of the casing.

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