Pumpable Anode Slurry for Uniform Well Casing Protection
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Solution Overview
Problem
Cathodic protection systems face challenges in achieving uniform current distribution and efficient protection for underground metallic structures, particularly in hydrocarbon producing wells and water injectors/producers, due to varying formation electric resistivity, high initial costs, maintenance issues, and interference with neighboring structures.
Innovation Solution
A liquid anode composition in the form of a slurry comprising a granulated electrical conducting material and a carrier fluid, which can be pumped into underground formations to provide cathodic protection, with optional high electrical conductivity backfill and viscosifiers, allowing for uniform distribution and effective corrosion prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If impressed current cathodic protection systems are used to provide large currents for deep casing areas, then protection current magnitude is improved, but current distribution uniformity deteriorates due to heterogeneous formation electric resistivity
Solution Approach 1:
The patent divides the anode into multiple discrete segments or blocks positioned at different depths along the casing. Each anode segment independently provides protection current to its local zone, ensuring uniform current distribution along the entire casing length without the heterogeneity problems of single-point impressed current systems.
Solution Approach 2:
The patent applies different anode materials or configurations at different locations along the casing based on local formation resistivity conditions. Each location receives tailored anode characteristics optimized for its specific electrical environment, achieving both adequate current magnitude and uniform distribution.
2Reliability
If sacrificial anodes are located close to the cathode to achieve proper protection current, then protection effectiveness is improved, but system complexity and installation difficulty increase
Solution Approach 1:
The patent uses a slurry formulation that can be pumped and injected into the formation through the casing. This hydraulic delivery method simplifies installation by allowing the anode material to be delivered as a fluid that sets in place, eliminating complex mechanical installation procedures while ensuring proper anode positioning for effective protection.
Solution Approach 2:
The patent changes the physical state of the anode material from solid blocks to a pumpable slurry formulation. This parameter change enables easy transportation and injection through standard well completion equipment, reducing installation complexity while maintaining the ability to position anodes effectively close to the casing for optimal protection.
3Ease of manufacture
If anode material is pumped into underground formation as slurry, then ease of installation is improved, but control over anode placement precision may deteriorate
Solution Approach 1:
The patent incorporates positioning elements or导向 structures within the slurry formulation or delivery system that guide the anode material to predetermined locations before it sets. This preliminary positioning action ensures precise placement is achieved during the pumping process itself, maintaining both ease of installation and placement precision.
Solution Approach 2:
The patent employs monitoring during the slurry injection process to track the position and distribution of anode material as it is pumped into the formation. This real-time feedback allows operators to adjust injection parameters to achieve precise anode placement while maintaining the simplicity of the pumped installation method.
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 slurry composition ensures consistent cathodic protection by achieving uniform current distribution and reducing maintenance needs, enhancing the efficiency and durability of cathodic protection systems while minimizing interference with neighboring structures.
Implementation Method 1
The composition comprises a slurry comprising a granulated electrical conducting material
Implementation Method 2
The carrier fluid has a viscosity adequate to carry all particulate solid materials
Data Source
AI summary
An anode slurry for cathodic protection to underground metallic structures, preferably for casings of hydrocarbon producing wells or water injecting/producing wells, comprising a granulated electrical conducting material as anode and optionally a granulated filler with high electrical conductivity (backfill). There is also disclosed a method for providing cathodic protection to underground metallic structures by injecting an anode slurry into the underground formation containing the metallic structures.