PDM (positive displacement motor) drilling tool for well drilling

Abstract

The invention relates to a PDM (positive displacement motor) drilling tool for well drilling, comprising a bypass valve assembly, a motor assembly, a universal shaft assembly and a driving shaft assembly, wherein the driving shaft assembly comprises a driving shaft shell, a driving shaft and a whole floating type thrust bearing; the whole floating type thrust bearing comprises a bearing shell, a plurality of bearing moving rings and a plurality of bearing static rings; a shaft sleeve is arranged between every two bearing moving rings; the bearing moving rings and the bearing static rings are all fastened and sleeve the driving shaft; two bearing static rings sleeve each shaft sleeve at intervals; an annular flange is formed on the inner wall of the bearing shell positioned between every two bearing static rings; a shock-absorption energy storage body is respectively arranged between the annular flange and every two bearing static rings; a plurality of long slots are formed in the lateral wall of each bearing static ring along the axial direction of the bearing shell; a bolt is connected with the position, corresponding to each long slot, of the bearing shell; the end part of each bolt extends into the corresponding long slot; each bearing static ring is matched with the corresponding bearing moving ring through two diamond compacts; one diamond compact is arranged on the corresponding bearing static ring; the other diamond compact is arranged on the corresponding bearing moving ring.

Description

technical field [0001] The invention relates to a screw drilling tool for drilling, belonging to the technical field of drilling tools. Background technique [0002] At present, screw drilling tools are mostly used in the drilling process of oil and natural gas exploration and development, and the screw drilling tools are mainly composed of bypass valve assembly, motor assembly, cardan shaft assembly and transmission shaft assembly connected in sequence. There are several deficiencies in the existing screw drilling tools: first, the thrust bearings in the transmission shaft assembly mostly adopt ball diagonal bearings (also called string bearings), and this bearing has both corrosion resistance and abrasion resistance. Weaker and short working life; there are also attempts to design diamond sliding thrust bearings, but their impact resistance is weak, the working life is short and unstable under alternating impact loads. Second, the stator in the motor assembly is mainly co...

AI Technical Summary

Problems solved by technology

There are several deficiencies in the existing screw drilling tools: first, the thrust bearings in the transmission shaft assembly mostly adopt ball diagonal bearings (also called string bearings), and this bearing has both corrosion resistance and abrasion resistance. Weaker, short working life; there are also attempts to design diamond sliding thrust bearings, but their impact resistance is weak, the working life is short under alternating impact loads, and it is unstable

Second, the stator in the motor assembly is mainly composed of non-uniform-wall-thick rubber bushings. The obvious problem is that the rubber bushes have large additional deformation, high heat generation, slow heat dissipation, and low conversion efficiency, so it is difficult to meet the work requirements.

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