Non-rotating Drill Pipe Protector With Hydrodynamic Bearings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current non-rotating drill pipe protectors (NRPs) face significant limitations due to substantial torsional friction generated by thrust loads, which reduce their durability and economic performance, especially when used in Managed Pressure Drilling with Rotating Control Heads, where higher collar gripping loads are necessary.
Innovation Solution
The implementation of a non-rotating drill pipe protector that incorporates multiple hydrodynamic bearings in both radial and thrust directions using flexible bearing surfaces and drilling fluids, featuring a collar and sleeve design with circumferential rings and grooves, creating fluid bearings to reduce friction and increase resistance to slipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional NRP designs use low-friction materials to reduce radial friction, then rotational friction in the radial direction is reduced, but substantial torsional friction from thrust loads remains, causing wear and limiting durability
Solution Approach 1:
The patent replaces conventional mechanical contact-based thrust bearings with hydrodynamic fluid bearings that use drilling fluid to create a lubricating film between the collar and sleeve surfaces. This substitution eliminates direct mechanical contact, reducing torsional friction from thrust loads while improving durability and reducing wear on the protector assembly.
Solution Approach 2:
The invention employs hydraulic principles by utilizing drilling fluid (mud) to create hydrodynamic bearings that support thrust loads. The fluid pressure and viscosity characteristics are exploited to maintain a lubricating film, reducing friction and wear. This hydraulic approach allows the system to handle high thrust loads while minimizing mechanical contact and associated wear.
2Adaptability or versatility
If clamp-on type protectors increase collar gripping loads to pass through Rotating Control Heads, then the protector can operate in Managed Pressure Drilling, but the assembly slips on the drill pipe at lower loads
Solution Approach 1:
The collar is divided into multiple circumferential rings (3-12 rings) that are distributed around the drill pipe. Each ring acts as an independent bearing element, distributing the gripping load across multiple contact points. This segmentation allows the collar to achieve higher total gripping capacity while preventing slippage at any single location, enabling operation in Managed Pressure Drilling with Rotating Control Heads.
3Object-affected harmful factors
If the NRP bearing body does not rotate relative to the drill pipe, then wear to the drill pipe and wellbore is prevented, but substantial torsional friction from thrust loads is generated, limiting the useful life of the protector
Solution Approach 1:
The patent replaces direct mechanical contact between the bearing body and drill pipe with a hydrodynamic lubricating film. The drilling fluid creates a fluid film that separates the non-rotating bearing body from the rotating drill pipe, eliminating mechanical contact and associated wear while reducing torsional friction from thrust loads through fluid film lubrication.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly reduces overall friction by 10-35% compared to conventional NRPs, enhances durability, and allows for higher gripping loads, thereby improving the performance and longevity of the protector in challenging drilling conditions.
Implementation Method 1
multiple hydrodynamic fluid bearings are created within the NRP assembly in both the circumferential and axial directions
Data Source
AI summary
A non-rotating drill pipe protector comprising a collar for attachment to a drill pipe and a sleeve positioned around the collar wherein drilling fluid passing between flexible bearing surfaces between the collar and the sleeve generate hydrodynamic bearings in both an axial and thrust direction of the drill pipe.