Downhole Grout Delivery Piston Actuation and Pressure Relief
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Solution Overview
Problem
Existing downhole grout delivery systems face challenges in ensuring pistons move in concert to maintain accurate proportions of grout components and in retrieving the tool assembly due to residual fluid pressure differentials.
Innovation Solution
A downhole tool assembly with cartridges containing grout components, where fluid pressure initiates piston movement in concert and bypasses an actuator to ensure consistent movement, and a pressure relief system to facilitate retrieval by equalizing hydrostatic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluid pressure is used to move pistons in the grout delivery system, then the grout components can be delivered to the downhole location, but residual fluid pressure differentials prevent retrieval of the tool assembly
Solution Approach 1:
A pressure relief valve is pre-configured in the tool assembly that automatically opens when fluid pressure drops below a threshold level, allowing residual pressure to be relieved before retrieval operations begin. This preliminary pressure relief action prevents the retrieval problem from occurring in the first place
Solution Approach 2:
The residual fluid pressure that initially causes retrieval difficulties is converted into a beneficial force by using it to drive the pistons during grout delivery. The system is designed to utilize this pressure for its primary function, then systematically relieve it through the pressure relief valve mechanism
2Ease of operation
If pistons are moved by fluid pressure alone, then the system is simple to operate, but pistons may not move in concert maintaining accurate grout component proportions
Solution Approach 1:
An actuator mechanism serves as an intermediary between the fluid pressure source and the pistons. The actuator translates fluid pressure into synchronized mechanical motion of multiple pistons, ensuring they move in concert while maintaining the simplicity of fluid-pressure-based actuation
Solution Approach 2:
The system replaces complex mechanical linkage systems with a fluid-pressure-based actuation mechanism. Fluid pressure serves as the control medium to synchronize piston movement, eliminating the need for complex mechanical coupling while maintaining precision
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
Ensures accurate mixing and delivery of grout by maintaining synchronized piston movement and simplifies retrieval by managing fluid pressure differentials, enhancing the efficiency and reliability of the grout delivery process.
Implementation Method 1
fluid pressure acts on the pistons to cause the pistons to move along their respective cylinders, thereby causing volume contraction of the chambers
Implementation Method 2
an actuator, whereby fluid pressure can act initially upon the actuator to initiate movement of the pistons in concert
Implementation Method 3
a pressure relief system to facilitate retrieval by equalizing hydrostatic pressure
Data Source
AI summary
A grout delivery system for delivery of a grout as a flowable substance comprising a mixture of two grout component materials at a downhole location. The grout delivery system comprises an elongate body comprises two reservoirs configured as cartridges for receiving respective charges of the two grout component materials. The two cartridges each comprise a piston. A selectively openable closure configured as a valve is provided adjacent the bottom end of each cylinder. Each piston is operably to progressively advance towards the valve, thereby expelling grout component material from the respective cartridge through the valve. When the grout delivery system is at the desired location downhole and a fluid seal established downhole, fluid such as water is pumped into the drill string and pressurized. Initially, fluid pressure is exerted on the two pistons indirectly via an actuator to initiate movement of the two pistons in concert. At a later stage, fluid under pressure is exerted directly on the pistons to continue their movement in concert. Retrieval of the grout delivery system may necessitate relief of the hydrostatic pressure differential across the fluid seal established downhole so that the grout delivery system can be lifted relatively easily from the downhole drilling assembly. A selectively operable pressure relief system is provided for this purpose.