Fines Fixing Agent pH Adjustment for Borate Fracturing Fluid Compatibility
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Solution Overview
Problem
The high pH of the fines-fixing agent FSA-1, due to its high concentration of unreacted caustic, affects the stability of the fracturing fluid system and promotes precipitation of organic crosslinkers, leading to compatibility issues with organo-borate crosslinkers, particularly in offshore completions.
Innovation Solution
The pH of FSA-1 is reduced to 6 or lower using acids like hydrochloric or acetic acid, improving its compatibility with organic complexed borate fracturing fluids by neutralizing the caustic and preventing precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fines-fixing agent FSA-1 is used with high concentration of unreacted caustic, then it provides effective fines fixation, but it causes high pH which promotes precipitation of organic crosslinkers and reduces fluid stability
Solution Approach 1:
The patent applies parameter changes by adjusting the pH of the fines-fixing agent from high (caustic) to low (acidic, specifically pH 2-4) using acids such as hydrochloric acid, nitric acid, or acetic acid. This parameter change resolves the contradiction by preventing crosslinker precipitation while maintaining fines fixation effectiveness, as demonstrated by the stable fluid system observed in Example 1 where no precipitation occurred after 24 hours at elevated temperature.
2Adaptability or versatility
If the pH of FSA-1 is reduced using acids, then compatibility with organo-borate crosslinkers is improved and precipitation is prevented, but additional chemical components and processing steps are required
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the pH of the fines-fixing agent to acidic levels (pH 2-4) before its introduction into the fracturing fluid system. This preliminary pH adjustment ensures immediate compatibility with organo-borate crosslinkers upon mixing, preventing precipitation from the outset. The acid treatment is performed in advance during FSA-1 preparation, simplifying the overall formulation process despite the additional step.
3Ease of manufacture
If high pH FSA-1 is used, then the original formulation is simple, but it promotes precipitation of organic crosslinkers particularly in offshore completions
Solution Approach 1:
The patent converts the harmful high pH property of FSA-1 into a beneficial low pH property by deliberately adding acids (hydrochloric, nitric, or acetic acid) to reduce the pH to 2-4. This conversion transforms the original formulation's disadvantage (high pH causing precipitation) into an advantage (low pH ensuring stability and compatibility), while the acid components themselves become beneficial agents that prevent crosslinker precipitation in the fracturing fluid system.
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 reduced pH formulation of FSA-1 enhances compatibility and stability with organo-borate crosslinkers, delaying or preventing precipitation and maintaining fluid viscosity over time, as demonstrated by rheology testing and visual observations.
Implementation Method 1
The pH of FSA-1 is reduced to 6 or lower using acids like hydrochloric or acetic acid, improving its compatibility with organic complexed borate fracturing fluids by neutralizing the caustic and preventing precipitation.
Data Source
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AI summary
A fines-fixing agent that has improved compatibility with organic complexed borate fracturing fluids is disclosed. Existing fines fixing agents have a high concentration of unreacted caustic that results in a product pH of approximately 12. This high pH affects the crosslinker and the overall fracturing fluid system stability, promoting precipitation of the organic crosslinker. These effects can be mitigated by neutralizing the fines fixing agents with an acid such as hydrochloric or acetic acid to a pH of 6 or lower.