Delayed Gelation Polymer System for High Temperature and Salinity
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Solution Overview
Problem
Existing polymer gelation systems are unstable in high temperature and high salinity environments, and require additional delayed gelling agents for delayed gelation, which limits their effectiveness in oil field applications.
Innovation Solution
A delayed gelation polymer system comprising acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, polyethylene glycol diacrylate, sodium formate, and polyethyleneimine as a crosslinker, in inverse emulsion form, with a temperature stabilizer like thiourea, which allows gelation at temperatures between 80-130°C and high salinity brines without the need for additional delayed gelling agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polymer gelation systems are used to block high permeability zones, then sweep efficiency is improved, but the systems cannot form stable gels in high temperature and high salinity environments
Solution Approach 1:
The patent uses inverse emulsion form polymer with specific concentration ranges (25-35% polymer, 50-90% acrylamide, 10-50% AMPS) and controlled crosslinker amounts (100-1500 ppm polyethyleneimine) to enable gel formation in high temperature (80-130°C) and high salinity (50,000-200,000 mg/L TDS) conditions where conventional systems fail
Solution Approach 2:
The patent creates a composite polymer system combining acrylamide, AMPS, polyethylene glycol diacrylate, and polyethyleneimine crosslinker in inverse emulsion form, which provides both the stability needed for high temperature/salinity environments and the delayed gelation capability required for deep zone penetration
2Loss of time
If delayed gelation is achieved using traditional methods with delayed gelling agents, then gelation time is delayed for deep zone placement, but the system requires additional components increasing complexity
Solution Approach 1:
The patent removes the need for separate delayed gelling agents by incorporating delayed gelation capability directly into the polymer-crosstlinker system itself, eliminating additional components while maintaining the ability to delay gelation until the polymer reaches the target deep zone
Solution Approach 2:
The polymer system performs multiple functions: it provides delayed gelation, maintains stability in high temperature and salinity, and enables deep zone penetration without requiring separate specialized agents for each function, reducing overall system complexity
3Strength
If polymer concentration is increased to form stable gels, then gel strength is improved, but viscosity increases preventing effective penetration into deep zones
Solution Approach 1:
The patent creates a dynamic system where the polymer maintains low viscosity (1-10 cp) in its initial state for easy injection and deep penetration, then transforms into a high-strength gel after reaching the target zone through temperature-triggered gelation and crosslinking
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 system forms stable gels deep within high permeability zones, improving sweep efficiency for oil-bearing zones by penetrating effectively and maintaining low viscosity before gelation, thus enhancing oil production.
Implementation Method 1
a crosslinker comprising polyethyleneimine; wherein the polymer is in inverse emulsion form
Implementation Method 2
wherein the polymer is in inverse emulsion form
Implementation Method 3
a temperature stabilizer; and wherein the polymer system undergoes gelation at a temperature between about 80-130 degrees Celsius
Data Source
AI summary
This disclosure describes the composition and methods of use for a novel delayed polymer gelation system for high temperature and high salinity applications. This polymer gelation system includes a polymer of acrylamide, AMPS and 500-5000 ppm polyethylene glycol diacrylate in inverse emulsion form, and a polyethyleneimine (PEI) with a MW of 2,000-30,000 daltons as the crosslinking agent.