Green Potassium Tetraborate Formulation for Pyrite Scale Removal
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Solution Overview
Problem
Current methods for removing iron sulphide scales in oil and gas wells, such as hydrochloric acid, generate toxic hydrogen sulphide and have high corrosion rates, and are inefficient for hard iron sulphides like pyrite and marcasite, leading to formation damage and production stoppages.
Innovation Solution
A new green formulation using potassium tetraborate tetrahydrate (K2B4O7-4H2O) at a concentration of 14 wt.%, which dissolves pyrite without generating H2S and has a significantly lower corrosion rate, effectively removing iron sulphide scales at 150° C and 1000 psi.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrochloric acid is used to dissolve iron sulphide scales, then the dissolving power is improved, but toxic hydrogen sulphide is generated and corrosion rate increases
Solution Approach 1:
The patent changes the chemical parameters by replacing hydrochloric acid with a green formulation containing chelating agents (such as EDTA, DTPA, NTA) and a converter salt (such as potassium tetraborate). This parameter change enables effective scale dissolution while avoiding toxic H2S generation and reducing corrosion rates by 25 times compared to conventional acid treatment
Solution Approach 2:
The patent introduces chelating agents as intermediary substances that form stable complexes with iron ions, facilitating scale dissolution without direct acid-rock reactions that produce H2S. The converter salt acts as an intermediary to convert insoluble iron sulphides into soluble complexes, enabling effective removal while eliminating harmful byproducts
2Reliability
If hydrochloric acid is used to dissolve iron sulphide scales, then the dissolving power is improved, but corrosion rate increases
Solution Approach 1:
The patent changes the chemical composition parameters by substituting aggressive hydrochloric acid with a green formulation comprising chelating agents and converter salts. This parameter transformation maintains effective scale dissolution capability while reducing corrosion rates by 25 times, as the chelating mechanism is inherently less corrosive to downhole tubulars and equipment
3Object-generated harmful factors
If conventional green formulations are used to remove iron sulphide scales, then H2S generation is reduced, but pyrite solubility is insufficient
Solution Approach 1:
The patent employs a composite formulation system combining chelating agents (EDTA, DTPA, NTA) with a converter salt (potassium tetraborate). This composite approach synergistically enhances pyrite dissolution capability beyond what single-component green formulations achieve, while maintaining H2S-free operation. The chelating agent binds iron ions while the converter facilitates the conversion of insoluble pyrite into soluble complexes
Solution Approach 2:
The patent optimizes formulation parameters including pH control and concentration ratios of chelating agents to converter salts. By adjusting these parameters, the formulation achieves superior pyrite solubility and dissolution kinetics compared to conventional green formulations, while maintaining the environmental benefit of zero H2S generation
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 new formulation increases pyrite solubility by 16% compared to previous green formulations and reduces corrosion rates by 25 times that of 15 wt. % HCl, while being cost-effective and environmentally friendly.
Implementation Method 1
a new green formulation using chelating agents... have been developed. It has the ability to dissolve iron sulphide field scale that contain Pyrrhotite (Fe7S8), Pyrite (FeS2) & Siderite (Fe2CO3)
Implementation Method 2
Molecular and electronic structure elucidation of Fe 2+/Fe 3+ complexed chelators used in iron sulphide scale removal in oil and gas wells
Data Source
AI summary
New formulation for pyrite scale removal from oil and gas wells and a method of pyrite scale removal are disclosed. The chemical formulation is composed of K2B4O7-4H2O, in a concentration of about 9-20 wt. % of the composition, preferably about 14 wt. % of the composition. The new formulation has the ability to dissolve pyrite without generation of the toxic H2S. Furthermore, the new formulation is cheaper and has very low corrosion rate compare to 15 wt. % HCl with corrosion inhibitor. The disclose method uses the disclosed new formulation to dissolve iron sulphide scale, performed at about 100-150° C. and about 500-2000 psi.