Solid Scale Inhibitor Composition for Oil Wells
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Solution Overview
Problem
Conventional solid scale inhibitors for oil and gas wells have limited lifespan and can cause formation damage due to insoluble obstructions, and existing methods for extending their life are cumbersome and pH-dependent, leading to inefficient scale inhibition.
Innovation Solution
A composition of hydroxyapatite (HA) and di- and tetra-non-amino phosphonates, which forms calcium precipitates before injection, eliminating the need for long shut-in times and allowing direct injection, thus providing a long-lasting, soluble scale inhibitor that can reach smaller spaces and prevent scale buildup without causing formation damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional scale inhibitors are attached to insoluble surfaces (diatomaceous earth, clays, graphite) to prolong lifespan, then the scale inhibitor lifespan is extended, but insoluble obstructions are left in pore spaces causing formation damage
Solution Approach 1:
The invention changes the solubility parameter of the scale inhibitor carrier from insoluble (conventional diatomaceous earth, clays, graphite) to soluble (sugar alcohol polymers). This allows the carrier to dissolve completely after delivering the scale inhibitor, eliminating formation damage while maintaining extended lifespan through controlled dissolution rates.
Solution Approach 2:
The invention creates a composite material combining sugar alcohol polymers with scale inhibitor molecules. The polymer provides a soluble, biodegradable carrier matrix that can be functionalized with phosphonate or carboxylate groups to bind scale inhibitors, creating a material that兼具 long-term protection and complete solubility.
2Duration of action of stationary object
If precipitation methods are used to extend scale inhibitor life, then lifespan is prolonged, but the process is cumbersome and pH-dependent
Solution Approach 1:
The invention extracts the pH-dependency and complexity from the precipitation process by using sugar alcohol polymers that form soluble complexes with scale inhibitors through simple mixing. This eliminates the need for controlled precipitation conditions, pH adjustment, and complex processing steps while achieving extended lifespan through controlled dissolution.
3Reliability
If particle size is decreased for improved anti-scale operations, then scale inhibition effectiveness is improved, but the scale inhibitor may be washed away more quickly
Solution Approach 1:
The invention uses sugar alcohol polymer composites that can be formulated as fine particles for effective penetration into small conduits and fractures. The polymeric nature provides controlled dissolution that retains fine particles in place, preventing them from being washed away while maintaining the effectiveness benefits of small particle size.
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 composition achieves extended lifespan and improved anti-scale operations with a low minimum inhibitor concentration, reducing the risk of formation damage and maintaining effective scale inhibition for several years, even under high water production rates.
Implementation Method 1
forms calcium precipitates before injection
Implementation Method 2
A composition of hydroxyapatite (HA) and di- and tetra-non-amino phosphonates, which forms calcium precipitates
Data Source
AI summary
A scale inhibitor includes an amount of hydroxyethylidene diphosphonic acid (HEDP), and an amount of hydroxyapatite. The amounts are combined to form a composition that is long lasting, high activity and completely dissolvable. The composition has a preferred particle size of less than 200 nm. Dicalcium phosphate, tricalcium phosphate, bone and/or bone ash may be used in place of hydroxyapatite.