Synergistic Filter Cake Breaking System for Wide Temperature Ranges
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Solution Overview
Problem
The presence of filter cake on subterranean formation faces hinders fluid flow in injection and production wells, requiring higher pump fracturing pressures and existing methods for filter cake removal are inefficient across varying wellbore temperatures and conditions.
Innovation Solution
A synergistic filter cake breaking system (SFBS) comprising a lower-temperature breaker and a higher-temperature breaker, both activated as acid precursors, which release acids at specific temperature ranges to facilitate continuous acid generation, effectively removing filter cake over a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single acid precursor breaker is used, then the filter cake removal is effective at a specific temperature range, but the performance deteriorates when wellbore temperature varies
Solution Approach 1:
The single acid precursor breaker is segmented into multiple acid precursors, each with distinct hydrolysis activation temperatures. This segmentation allows the breaker system to operate effectively across a broader temperature range by dividing the temperature coverage into multiple zones, with each precursor becoming active in its specific temperature range.
Solution Approach 2:
The invention uses a composite breaker system comprising multiple acid precursors with different thermal activation characteristics. This composite approach combines materials that hydrolyze at different temperatures, creating a synergistic effect that maintains reliable filter cake removal performance across varying wellbore temperature conditions.
2Productivity
If higher pump fracturing pressures are used to inject past the filter cake, then fluid flow through injection wells is improved, but the energy consumption and equipment requirements increase
Solution Approach 1:
The acid precursors are injected into the wellbore before the main flooding operation. They undergo hydrolysis to generate acid in situ, which preliminarily dissolves and removes the filter cake, creating a cleaner pathway for subsequent fluid injection. This preliminary filter cake removal reduces the resistance to flow, allowing lower pump fracturing pressures to achieve the same productivity.
3Speed
If the hydrolysis rate of ester-based breakers is increased, then the filter cake cleanup speed is improved, but the control over acid release becomes less predictable across different wellbore conditions
Solution Approach 1:
Each acid precursor in the composite system is designed with specific local quality characteristics, including distinct hydrolysis activation temperatures and rate constants. This allows the system to provide controlled acid release at different stages and locations within the temperature gradient of the wellbore, maintaining predictable performance across varying conditions.
Solution Approach 2:
The invention changes the key parameter of hydrolysis activation temperature across the different acid precursors. By selecting precursors with progressively different activation temperatures, the system achieves a controlled, staged release of acid that adapts to the temperature profile of the wellbore, providing consistent performance across different wellbore conditions.
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 SFBS enables efficient filter cake removal across a broad temperature range, minimizing pressure requirements and optimizing fluid flow, while being tunable for specific wellbore conditions.
Implementation Method 1
The rate of hydrolysis of these esters and consequently the rate of filtercake cleanup depends on numerous factors such as wellbore temperature, pH and ester type.
Data Source
AI summary
A breaker composition comprising (i) a first acid precursor, (ii) a second acid precursor and (iii) an aqueous fluid wherein the first acid precursor has an effective operating temperature of from about 15° C. to about 120° C. and the second acid precursor has an effective operating temperature of from about 30° C. to about 180° C.