Non-magnetic Screw Stator

I. Core Functions

1. Establishing the power foundation: It works in conjunction with the rotor to form a sealed chamber. When high-pressure mud pumped by the mud pump enters the chamber, it drives the rotor to perform planetary motion. This motion is then converted into axial rotation via a universal joint, enabling the drill bit to rotate and achieve rock drilling. Additionally, specially designed non-magnetic screw stators (such as those with an outer contour spiral) can generate upward force underground, facilitating the return of sand and rock debris with the mud, thereby reducing wear on the screw components caused by sand accumulation.

2. Ensuring measurement accuracy: In directional oil drilling, the drilling trajectory must be controlled using measurement sondes. However, conventional steel stators are prone to magnetization, which can interfere with the magnetic measurement signals of the sondes. Non-magnetic stators avoid self-magnetization, creating a stable non-magnetic environment for measurement instruments. This significantly reduces the impact on measurement accuracy, enabling more precise control of the drilling trajectory.

II. Key Features

1. Strong magnetic stability: This is its core characteristic, requiring strict control over the material's permeability to ensure a consistently non-magnetic state under prolonged high-pressure and high-temperature downhole conditions, preventing any impact on surrounding measurement equipment due to magnetic variations.

2. Wear-resistant and corrosion-resistant: Drilling mud often contains hard particles such as rock cuttings and sand, and some mud is corrosive. The stator must possess excellent wear resistance to withstand particle erosion while also resisting mud corrosion, preventing cavity damage that could lead to seal failure.

3. High structural adaptability: The internal spiral line parameters of the stator must precisely match those of the rotor to ensure the sealing integrity of the sealed cavity, thereby guaranteeing power transmission efficiency. Additionally, its external structural design must align with the overall assembly of the drill string, such as some stators featuring a helical outer contour to accommodate downhole fluid circulation requirements.

III. Common Manufacturing Materials and Applicable Scenarios

Material selection must balance requirements such as non-magnetic properties, strength, and corrosion resistance. Different materials are suitable for different working conditions, as detailed below: