Mud Motor Stall Protector with Pressure-Actuated Piston

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Mud motors often stall due to insufficient torque, leading to fluid flow cutting and erosion of sealing surfaces when the motor cannot rotate, causing delays and increased costs.

Innovation Solution

A mud motor stall protector with a housing and a piston that moves in response to pressure differentials, reducing fluid flow area and creating a pressure drop to disengage the drill bit from the formation, allowing for safe restart of the motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mud motor operates without rotation due to insufficient torque, then the fluid flow continues through the motor, but this causes flow cutting and erosion of sealing surfaces resulting in damage

Engineering Contradiction:

Improvemud motor durabilityVSAvoidflow cutting and erosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The device applies preliminary anti-action by using a piston mechanism that responds to pressure differentials to close flow passages and redirect fluid flow before significant erosional damage can occur to the sealing surfaces. The piston translates in response to pressure differential to occupy flow passages and redirect fluid away from the stalled motor.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The device converts the harmful high-velocity fluid flow that causes erosion into a beneficial force by using the fluid pressure itself to actuate the piston mechanism. The pressure differential that would normally cause damage is instead harnessed to trigger the protective action of redirecting flow away from vulnerable surfaces.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If the drill bit remains engaged with the formation during a stall, then torque is continuously applied, but this prevents the motor from restarting and extends downtime

Engineering Contradiction:

Improvedrilling operation continuityVSAvoidmotor stall downtime

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The device performs preliminary action by automatically redirecting fluid flow away from the stalled motor before the operator can respond, and maintaining this redirected flow state until the drill bit disengages from the formation. This preliminary redirection prevents the motor from attempting to restart under load, which would cause repeated stalling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The device implements feedback by using the pressure differential across the piston seals as a sensing mechanism. When the drill bit disengages and normal rotation resumes, the pressure differential changes, causing the piston to return to its original position and restore normal fluid flow through the motor, thereby automatically signaling the system to resume operation.

Inventive Principle:

Principle #23Feedback

3Power

If fluid flow is continuously supplied to the mud motor, then the motor can generate torque when needed, but during a stall this continuous flow causes erosional damage to internal surfaces

Engineering Contradiction:

Improvetorque generation capabilityVSAvoiderosional damage

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The device applies dynamics by making the fluid flow path dynamic rather than static. The piston can translate between positions to occupy or leave open the flow passages, allowing the system to dynamically adjust fluid distribution based on operational conditions. This dynamic control enables the system to maintain power generation capability while preventing erosion during stalls.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The device uses the piston as an intermediary element between the fluid supply and the mud motor. The piston mediates the fluid flow by selectively occupying or leaving open the flow passages, thereby controlling whether fluid reaches the motor based on the pressure differential signal, thus protecting the motor from erosive flow during stall conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The protector prevents erosional damage by ensuring the motor remains free of fluid flow until pumps are shut down, reducing downtime and maintenance costs by allowing safe disengagement and restart of the drilling operation.

Implementation Method 1

a piston disposed within the housing and defining a fluid flow channel therein, the piston being first responsive to a pressure differential across a set of piston seals resulting in piston movement

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

then responsive primarily to the restriction of the flow area of the fluid flow channel through the piston

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Data Source

PatentUS11041350B2Mud motor stall protector

Publication Date: 2021.06.22 BAKER HUGHES CO

AI summary

A mud motor stall protector including a housing, a piston translationally disposed in the housing, the piston defining a flow passage therein, and a pin positioned relative to the housing to occupy a portion of the flow passage of the piston or leave the flow passage of the piston open depending upon position of the piston relative to the pin.