DHSV Scale Removal Using Service-Line Acid Neutralization
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Solution Overview
Problem
Current methods for removing scale from Downhole Safety Valves (DHSV) in production strings of oil wells, particularly in pre-salt fields, result in production interruptions and equipment corrosion, as they require acid injection into the reservoir for neutralization, which is inefficient and damaging.
Innovation Solution
A method involving the use of a neutralizing solution in the service line before pumping acidic solutions to react with calcium carbonate scale in the DHSV, followed by neutralizing the spent acid in the service line, thereby reducing corrosiveness and preserving the piping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid injection into the reservoir is used for neutralization, then scale removal is achieved, but production interruption and equipment corrosion occur
Solution Approach 1:
The patent divides the production string into two separate circuits: a service line for injecting treatment fluids and a production line for maintaining continuous oil flow. This segmentation allows scale removal operations to proceed without interrupting production, as the acid is injected through the service line while oil continues to flow through the production line.
Solution Approach 2:
The patent introduces a neutralizing agent as an intermediary substance that reacts with excess acid in the service line. This neutralizing agent is injected into the service line after the acid treatment, converting harmful acidic effluent into neutral or slightly alkaline fluid that can be safely disposed of without corroding equipment or interrupting production.
2Reliability
If acid injection into the reservoir is used for neutralization, then scale is removed, but equipment corrosion increases
Solution Approach 1:
The patent introduces a neutralizing agent as an intermediary substance that reacts with excess acid in the service line. This neutralizing agent is injected into the service line after the acid treatment, converting harmful acidic effluent into neutral or slightly alkaline fluid that can be safely disposed of without corroding equipment or interrupting production.
Solution Approach 2:
The patent extracts the neutralization process from the production line and relocates it to the service line. By taking out the neutralization step and performing it separately in the service line, the patent prevents acidic fluids from contacting production equipment, thereby eliminating corrosion risks while maintaining scale removal effectiveness.
3Reliability
If traditional scale removal methods are used, then fouling is removed, but cleaning time increases
Solution Approach 1:
The patent maintains continuous production flow through the production line while scale removal operations proceed through the service line. This continuity eliminates idle time between production shutdown and scale removal, allowing both operations to occur simultaneously without interrupting the useful action of oil production.
Solution Approach 2:
The patent performs preliminary neutralization of the acid in the service line before the treated fluid could potentially affect production equipment. By advancing the neutralization step to occur in the service line prior to any potential contact with production systems, the patent prevents downstream corrosion issues and reduces overall operation time.
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 approach maintains production without interruption, reduces cleaning time, extends service line life, and lowers operational costs by minimizing equipment damage and time required for cleaning.
Implementation Method 1
the spent acid is mixed with the neutralizing solution inside the service line, thus reducing the corrosive attack to the piping
Implementation Method 2
the acid is pumped into the production string to react with the calcium carbonate scale
Data Source
AI summary
The present invention addresses to a method of removing scale from the DHSV of the oil production string aiming at maintaining the production of the wells and thus avoiding the loss of production. First, a neutralizing solution is placed in the service line, before pumping the scale removing solution through the string to act on the DHSV. Next, the acid is pumped into the production string to react with the calcium carbonate scale. After the time for the dissolution of the scale inside the DHSV, the well is opened for production by the service line. The spent acid is mixed with the neutralizing solution inside the service line, reducing its corrosiveness in relation to the service line, contributing to its preservation.