Selective Chemical Additive Injection Without Capillary Clogging
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Solution Overview
Problem
Existing chemical injection systems in hydrocarbon wells face issues with chemical evaporation and clogging due to void formation in capillary tubes, leading to inaccurate flowrate monitoring and reduced well performance, especially when annulus pressure drops below hydrostatic pressure.
Innovation Solution
A surface-controlled chemical injection system with downhole modules that utilize pressure differentials to inject additives into production tubing, allowing real-time adjustment and monitoring of chemical flow, eliminating the need for conventional capillary tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a capillary tube is used for chemical injection, then chemical additives can be delivered to the wellbore, but the chemical level drops below the surface causing void formation, evaporation, and clogging
Solution Approach 1:
The invention extracts the chemical injection function from the capillary tube system and relocates it to a surface-controlled valve system. The capillary tube is replaced with a valve assembly that can be opened and closed from the surface, eliminating the void formation problem while maintaining chemical injection capability.
Solution Approach 2:
The invention introduces a valve as an intermediary component between the chemical storage and the wellbore. This valve acts as a mediator that controls chemical flow without allowing the chemical level to drop below the surface, preventing evaporation and clogging while enabling reliable injection.
2Ease of operation
If check valves are used on capillary tube exit, then chemical flow can be controlled, but they cannot maintain fluid column when annulus pressure drops below hydrostatic pressure
Solution Approach 1:
The invention employs a dynamically controllable valve system that can adjust its state based on real-time pressure conditions. Unlike static check valves, the controlled valve can maintain the fluid column by opening only when annulus pressure is sufficient, dynamically adapting to pressure changes while ensuring reliable chemical injection.
3Reliability
If relief valves are used to maintain chemical level, then injection pump head requirements increase and valves can leak over time
Solution Approach 1:
The invention implements a self-regulating valve system that automatically maintains chemical level without requiring continuous pump head adjustment. The valve opens only when annulus pressure exceeds hydrostatic pressure, allowing the system to self-regulate chemical injection based on actual pressure conditions, eliminating the need for high pump head requirements.
4Productivity
If chemical level is not accurately monitored, then flowrates cannot be tracked, but chemical additives are costly and amounts injected should be low
Solution Approach 1:
The invention incorporates feedback mechanisms through pressure sensors and controlled valve operation that monitor annulus pressure in real-time. This feedback allows the system to automatically adjust valve opening based on actual pressure conditions, ensuring accurate flowrate monitoring and preventing chemical loss while optimizing injection efficiency.
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 and efficient injection of chemicals by maintaining a fluid column, preventing clogging, and allowing real-time adjustment of flowrates, thereby enhancing well performance and reducing operational costs.
Implementation Method 1
When the valve is opened, the chemical additive is injected into the tubing in response to a pressure differential between the annulus and tubing
Data Source
AI summary
An apparatus for producing fluid from a wellbore includes production tubing in the wellbore, an annulus around the tubing, and a chemical injection system for injecting chemical additive into the production tubing from the annulus. The chemical additive system includes an injection module with a valve that is selectively opened and closed by operating an actuator. When the valve is opened, the chemical additive is injected into the tubing in response to a pressure differential between the annulus and tubing. The injection module is surface-controlled and downhole conditions are monitored, so that a flow of chemical additive injection is initiated, adjusted, or suspended in real time.