Vibration-Resistant Seal for Downhole Tool

Abstract

A seal ring assembly for a well drilling tool that takes the place of conventional O-rings that are prone to costly downhole failures. In a first embodiment the seal ring assembly is configured with a convex adapter seal ring at one end, a concave adapter seal ring at the other end, and a number of V-shaped component seal rings packed in between the convex and concave adapter seal rings and positioned in the space between a drill collar mandrel and a pressure cylinder of the well drilling tool. In a second embodiment the seal ring assembly is configured with a number of X-shaped component seal rings, each of which is fitted with two O-rings. The seal ring assemblies are able to flex when operating in a bent drill hole so as to maintain seal integrity and prevent fluids from passing through to the electronics region of the well drilling tool.

Description

BACKGROUND[0001]1. Technical Field[0002]Various embodiments of the present invention relate to well drilling equipment, and more specifically, to seals for downhole drilling tools.[0003]2. Description of Related Art[0004]Downhole oil well drilling tools are exposed to extreme heat, pressure, bending, shock, and vibration. A typical well tool has one or more seals, such as O-rings, located in various places to isolate pressurized fluid from an atmospheric region. For instance, seals are typically found between the drill collar mandrel and pressure cylinder. The O-ring is intended to keep fluids out of the well tool assembly containing electronic components that may be damaged by moisture or pressure-conveyed fluids. The seals are subjected to vibrations and mechanical stress in the extreme heat and pressures encountered as the well is being drilled. These extreme conditions in combination with the dynamic motion between the mandrel and sealing surface on the mating cylinder contribut...

AI Technical Summary

Benefits of technology

[0005]Various embodiments of the present invention involve a seal ring assembly for a well drilling tool which has a plurality of component seal rings, each with a V-shaped concave surface on one face generally parallel to the V-shaped convex surface on the opposite face. The rings have an external and internal cylindrical surface joining the V-shapes faces. The component seal rings are positioned between a convex adapter seal ring and a concave adapter seal ring. The convex adapter seal ring has a V-shaped inner surface that mates with the V-shaped concave surface of a first component seal ring. The concave adapter seal ring has a V-shaped inner surface that mates with the V-shaped convex surface of the last component seal ring. The seal ring assembly is positioned in coaxial alignment between a drill collar mandrel and a pressure cylinder of the well drilling tool. Seals may be made from a relatively flexible material such as reinforced rubber or plastic. The seal material is typically chosen to have properties suitable for the environment bas

Problems solved by technology

Downhole oil well drilling tools are exposed to extreme heat, pressure, bending, shock, and vibration.

The seals are subjected to vibrations and mechanical stress in the extreme heat and pressures encountered as the well is being drilled.

These extreme conditions in combination with the dynamic motion between the mandrel and sealing surface on the mating cylinder contribute to O-ring seal failures.

For example, rotational bending can cause a gap to open and close between the conventional parts, letting liquid pass the seal.

Conventional O-rings are prone to downhole failure due to these conditions, sometimes causing inaccurate equipment readings, electrical shorts, destruction of electronics and sensors, leading to costly work stoppages.

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