Motor Saver Sub Hydraulic Valve Bypass for Downhole Overpressure
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Solution Overview
Problem
Down hole drilling motors face premature failure due to overpressure scenarios, leading to increased operational costs and downtime, as they struggle to maintain drilling motor pressures within specifications during high penetration rates in difficult formations.
Innovation Solution
A down hole tool, referred to as the motor saver sub, utilizing four hydraulic valves to control fluid circulation and maintain optimal drilling and hole cleaning pump rates, operates in two modes: normal operation and overpressure prevention, ensuring motor differential pressures remain within manufacturer specifications by redirecting fluid flow during overpressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling rate of penetration is increased in difficult formations, then productivity is improved, but motor differential pressure exceeds manufacturer specifications causing premature motor failure
Solution Approach 1:
A pressure control device is introduced as an intermediary component between the motor and the drilling system. This device monitors motor differential pressure and automatically diverts excess fluid through an annular bypass when pressure exceeds predetermined thresholds, thereby protecting the motor from overpressure damage while allowing high rates of penetration to be maintained
2Reliability
If fluid circulation rate is reduced to prevent overpressure, then motor differential pressure is controlled, but drilling and hole cleaning efficiency decreases
Solution Approach 1:
The fluid circulation system is segmented into two separate pathways: a primary path through the motor for drilling operations, and a secondary annular bypass path for pressure relief. The pressure control device selectively opens the bypass path when motor differential pressure exceeds thresholds, allowing excess fluid to circumvent the motor. This segmentation enables maintenance of optimal circulation rates through the motor while diverting surplus fluid, thus protecting the motor without compromising drilling or hole cleaning efficiency
3Reliability
If automatic pressure control is implemented, then motor protection is improved, but device complexity increases
Solution Approach 1:
The pressure control device operates autonomously using self-service principles. It incorporates pressure-sensing mechanisms that automatically detect when motor differential pressure exceeds predetermined thresholds and trigger bypass activation without external intervention. The system self-regulates by diverting fluid through the annular bypass when needed and automatically returning to normal operation when pressure normalizes, eliminating the need for complex external control systems or manual monitoring
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 motor saver sub effectively prevents motor damage by maintaining optimal drilling pressures, allowing for higher rates of penetration while protecting the motor from overpressure, resetting without altering circulation rates and ensuring continuous drilling operations within specified parameters.
Implementation Method 1
controlled by four hydraulic valves acting together to effectively open a circulation port to drilling annulus at a high pressure setting and close the circulation to annulus at a low pressure setting
Data Source
AI summary
A down hole drilling tool for preventing overpressure strain on surface pumping equipment or a down hole drilling motor having a housing and a circulation port and four hydraulic valves positioned on the housing actively working together to effectively open the circulation port to drilling annulus at a high pressure setting and dose the circulation port to annulus at a low pressure setting, the four hydraulic valves include a high pressure setting valve, a low pressure setting valve, a control valve and a fixed setting valve.