Chelating Agent for Reservoir Acidification
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Solution Overview
Problem
Conventional acidizing treatments for oil and gas wells require on-site preparation of acid solutions, leading to complex operations, high transportation and labor costs, and limited efficiency due to the need for multiple liquid phases and precipitation inhibition.
Innovation Solution
A chelating agent comprising methanesulfonic acid, methanol, polyaspartic acid, epoxy succinic acid, sodium cetyl sulfonate, and cetyltrimethylammonium bromide, which can be directly added to the acid solution to inhibit precipitation, dissolve rock cracks, and reduce surface tension, thereby simplifying the process and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional acid solution systems are used with on-site preparation, then the acidification treatment can be performed, but the operation process becomes complicated and transportation cost increases
Solution Approach 1:
The patent combines multiple acid components (hydrochloric acid, hydrofluoric acid, methanesulfonic acid) and functional additives (chelating agents, surfactants, corrosion inhibitors) into a single integrated acid solution formulation. This merging eliminates the need for separate preparation of pre-liquid, treatment liquid, and post-liquid, simplifying the operation process while maintaining effective acidification treatment
Solution Approach 2:
The acid solution is designed to perform multiple functions simultaneously: it acts as both the treatment liquid for dissolving minerals and as the post-liquid for preventing secondary precipitation and corrosion. The inclusion of chelating agents like EDTA and surfactants like TX-100 enables the solution to handle multiple tasks in one application, reducing operational complexity
2Productivity
If conventional acid solutions are prepared and transported on-site, then the acidification can be performed, but transportation cost and labor intensity increase
Solution Approach 1:
The acid solution is pre-formulated with all necessary components including chelating agents and surfactants in optimal concentrations before reaching the site. This preliminary preparation of the complete acidification system eliminates on-site mixing and preparation time, allowing immediate deployment and reducing both transportation time and labor intensity
3Reliability
If conventional acid solutions are used, then mineral dissolution can occur, but secondary precipitation and corrosion problems arise
Solution Approach 1:
The patent introduces chelating agents (EDTA, polyaspartic acid) as intermediary substances that bind to metal ions released during mineral dissolution. These chelating agents prevent the metal ions from forming secondary precipitates by maintaining them in soluble complex forms, thus eliminating the harmful precipitation effect while preserving the beneficial mineral dissolution
Solution Approach 2:
The acid solution converts the potentially harmful effect of acid corrosion into a beneficial process by adding corrosion inhibitors that protect the wellbore and equipment. The chelating agents similarly convert the harmful secondary precipitation into a beneficial soluble complex formation, maintaining solution clarity and effectiveness throughout the treatment
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 chelating agent effectively inhibits secondary precipitation, dissolves calcium carbonate, and reduces interfacial tension, allowing for a single-step operation that improves well productivity, reduces operation costs, and prevents clay swelling, thus enhancing the acidizing process.
Implementation Method 1
dissolving some minerals in the formation rock or plugs in the pores and cracks
Implementation Method 2
the chelating agent for reservoir acidification and stimulating injection has a inhibition rate of calcium fluoride precipitation of more than 90%, a inhibition rate of fluorosilicate precipitation of more than 85%
Implementation Method 3
after use, the interfacial tension of the reservoir surface can be as small as 10−3
Data Source
AI summary
A chelating agent may be used for reservoir acidification and stimulating injection. The raw material composition of the chelating agent comprises: 10.0%-20.0% of methanesulfonic acid, 10.0%-20.0% of methanol, 10.0%-20.0% of polyaspartic acid, 10.0%-15.0% of epoxy succinic acid, 5.0%-10.0% of sodium cetyl sulfonate, 10.0%-15.0% of cetyltrimethylammonium bromide and the balance of water. The present disclosure also provides a preparation method of the above chelating agent. The chelating agent for reservoir acidification and stimulating injection may be used in an acidizing and stimulating injection process, wherein it can effectively dissolve rock cracks, be used directly without need to be reversed.