Well Acidizing Formulation for Damage Removal and Scale Inhibition
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Solution Overview
Problem
Existing acid stimulation methods for carbonate reservoirs cause damage due to incomplete solubilization of organic acids, leading to residue formation and increased carbonate precipitation, necessitating separate operations and higher costs.
Innovation Solution
A formulation of salts and phosphonic, sulfonic, and carboxylic acids with a pH less than 3.5 is used for simultaneous acid stimulation and inhibition, removing damage and preventing residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic acids are used for acid stimulation, then damage removal is achieved, but residue formation and carbonate precipitation occur due to incomplete solubilization
Solution Approach 1:
The patent changes the chemical parameters by using inorganic acids (hydrochloric, acetic, or formic acid) with controlled concentration and pH levels instead of organic acids, eliminating residue formation while maintaining damage removal effectiveness through complete solubilization
Solution Approach 2:
The patent converts the harmful effect of high alkalinity residual fluid into a beneficial process by controlling acid concentration and pH to ensure complete reaction and solubilization, preventing carbonate precipitation while achieving effective damage removal
2Reliability
If separate operations are conducted for acidification and inhibition, then each treatment is optimized, but operational time and costs increase
Solution Approach 1:
The patent merges acidification and inhibition operations into a single simultaneous treatment by injecting a formulated acid solution that contains both the acidifying agent and the inhibition mechanism, eliminating the need for separate operations and reducing operational time and costs
Solution Approach 2:
The acid solution formulated in the patent serves multiple functions simultaneously: it provides acidification for damage removal, controls pH to prevent precipitation, and incorporates inhibition capabilities, making it a universal treatment solution that replaces multiple separate operations
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 solution allows for a single operation to address both acid stimulation and inhibition, reducing operational costs and maintaining well integrity by preventing carbonate precipitation.
Implementation Method 1
the drill, when cutting carbonate rocks, causes grinding on the rock surface, generating debris, which when entering the natural porosity, cause damage to the formation, with a reduction in the effective permeability. This damage is usually removed by acid stimulation by applying hydrochloric, acetic, or formic acids
Implementation Method 2
the use of organic acids, which can generate residues due to incomplete solubilization or because they generate a residual aqueous fluid of high alkalinity (increase of the carbonate precipitation potential)
Data Source
AI summary
The invention addresses to a method of applying a formulation obtained from a mixture of phosphonic salts and acids (R1—P(OR2)(OR3)), sulfonic acids (R—SO3H) and/or carboxylic acids (R—COOH). The pH of this formulation must be less than 3.5, preferably between 2.0 and 3.5. The formulation can be manufactured by dilution in saline fluid at the WSSV facility, in product compatible tanks on the rig or offshore platform or stimulation boat. This formulation enables acid stimulation and inhibition of the well in the same operation, in addition to removing damage caused by the use of organic acids in carbonate oil and natural gas reservoirs.