Wet Grinding Device for Polymer Injection

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Solution Overview

Problem

The existing methods for enhanced oil recovery using water-soluble polymers, such as acrylamide and methacrylamide copolymers, are hindered by degradation issues and require extensive filtration and dissolution processes, limiting their direct injection into oil wells without prior tank dissolution and filtration.

Innovation Solution

A wet grinding device is used to disperse high molecular weight polymers directly into the injection pipeline, where the polymer dissolves during transport, eliminating the need for additional dissolution tanks and filtration, utilizing a rotor-stator assembly with a secondary water ring to prevent degradation and ensure complete dissolution during pipeline transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high molecular weight polymer is used to increase viscosity for enhanced oil recovery, then the viscosity improving effect is enhanced, but the polymer becomes more sensitive to degradation and harder to disperse without aggregation

Engineering Contradiction:

ImproveviscosityVSAvoidpolymer stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-dispersing the high molecular weight polymer in a small amount of water within the dispersion device before main injection. This preliminary dispersion prevents aggregation and degradation during the subsequent injection process, allowing the polymer to maintain its viscosity-enhancing properties while being transported through the pipeline to the injection well.

Inventive Principle:

Principle #10Preliminary action

2Strength

If polymer concentration in solution is increased to achieve required viscosity, then the viscosifying effect is improved, but aggregate formation increases requiring coarse and fine filtration

Engineering Contradiction:

ImproveviscosityVSAvoidfiltration system

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent extracts the filtration step from the traditional polymer injection process by using a high-shear dispersion device that completely prevents aggregate formation. The intense mixing action in the dispersion device ensures uniform polymer distribution at the required concentration without any fisheyes or aggregates, eliminating the need for both coarse (100-200 microns) and fine (10-20 microns) filtration systems.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If polymer is dispersed at high concentration to reduce dissolution time, then the injection efficiency is improved, but aggregate formation increases

Engineering Contradiction:

Improveinjection rateVSAvoidpolymer homogeneity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by using a high-shear dispersion device with rapidly rotating elements that create intense mixing action. This dynamic mixing process maintains uniform polymer distribution even at high concentrations (5 g/l or higher), preventing aggregate formation while enabling rapid dissolution and immediate injection without requiring preliminary low-concentration dispersion followed by gradual concentration increase.

Inventive Principle:

Principle #15Dynamics

4Stability of the object's composition

If residence time in dispersion device is increased to ensure complete dissolution, then polymer homogeneity is improved, but the injection timing is delayed

Engineering Contradiction:

Improvepolymer homogeneityVSAvoidinjection delay

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent replaces the traditional time-based dissolution approach with a mechanics-based solution. Instead of relying on prolonged residence time for polymer dissolution, the high-shear dispersion device uses intense mechanical mixing action to achieve complete polymer dispersion and dissolution instantaneously. This mechanical substitution allows the polymer to be fully homogenized during the injection process itself, eliminating the delay between dispersion and injection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This method allows for the direct injection of polymer solutions into oil wells without prior tank dissolution, maintaining polymer integrity and viscosity, and preventing well plugging, while maintaining the required concentration and viscosity for effective enhanced oil recovery.

Implementation Method 1

a rotor-stator assembly with a secondary water ring to prevent degradation and ensure complete dissolution during pipeline transport

Methodology Applied

Scientific EffectMechanical dispersion:

Implementation Method 2

where the polymer dissolves during transport, eliminating the need for additional dissolution tanks and filtration

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentUS7814977B2Installation for enhanced oil recovery using water-soluble polymers and method of implementing

Publication Date: 2010.10.19 S P C M SA

AI summary

Installation for enhanced oil recovery comprising in succession: a polymer storage hopper, a grinding device and a pressurized injection pump. The grinding device has a chamber for grinding and draining the dispersed polymer comprising a rotor and a stator, and on all or part of the periphery of the chamber, a ring fed by a secondary water circuit. The ring communicates with the chamber for spraying of pressurised water on the blades of the stator. A method implementing the installation is also provided.