Crosslinking Composition for Hydrocarbon Gel Stability
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Solution Overview
Problem
Current gelled fluids used in hydrocarbon recovery for formation fracturing face instability and degradation when exposed to stress and turbulence, particularly at low temperatures, making it difficult to maintain gel stability and effectively transport proppants to smaller fractures.
Innovation Solution
A crosslinking composition combining substituted imidazolines or pyrimidines, coconut oil diethanolamide, and a source of iron, specifically designed to enhance gel stability and performance in low-temperature applications, such as liquefied propane and liquefied natural gas fracturing, using a phosphate ester gelling agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional crosslinkers are used to form gels for hydrocarbon recovery, then gel formation is achieved, but gel stability deteriorates under stress and turbulence particularly at low temperatures
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the crosslinking system. Specifically, it uses a combination of imidazoline crosslinker (0.1-10 wt%), polyamine crosslinker (0.1-5 wt%), and iron salt catalyst (0.01-1 wt%) to create gels with enhanced stability. The patent also adjusts the phosphate ester concentration (1-20 L/m³) and uses specific ratios of crosslinkers to optimize gel performance under cold temperature and high stress conditions.
Solution Approach 2:
The patent employs composite materials by combining multiple crosslinking agents (imidazoline and polyamine) with iron salts and phosphate esters to create a synergistic crosslinking system. This composite approach allows the gel to exhibit both stability and reliability under challenging conditions, as the different components work together to form a robust three-dimensional network that resists degradation from stress, turbulence, and low temperatures.
2Stability of the object's composition
If gel stability is enhanced for cold temperature applications, then gel integrity is improved, but pumpability and flowability may worsen
Solution Approach 1:
The patent applies dynamics by creating a gel system that can adapt its properties based on environmental conditions. The gel maintains pumpability and flowability during injection but transitions to a more stable, intact structure once placed in the formation. This is achieved through the specific crosslinking mechanism that allows controlled gelation and the use of additives that prevent premature setting while ensuring adequate stability at cold temperatures.
3Strength
If gel strength is increased to maintain proppant suspension, then proppant transport capability is improved, but gel susceptibility to breaking worsens under turbulence
Solution Approach 1:
The patent uses composite materials by combining multiple crosslinking mechanisms (imidazoline-iron, polyamine-iron) to create a gel with both strength and turbulence resistance. The composite crosslinking system creates a more uniform and resilient three-dimensional network that can suspend proppant effectively while withstanding the mechanical stresses of turbulent flow better than conventional single-crosslinker systems.
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 provides improved stability and performance at very cold temperatures, ensuring effective gel formation and proppant transport, maintaining gel integrity and flowability in hydrocarbon recovery processes.
Implementation Method 1
crosslinking by injecting sources of iron or aluminum, as is known in the art
Implementation Method 2
form the basis of the gel, after crosslinking
Data Source
AI summary
A crosslinking composition for hydrocarbon gels containing phosphate ester gelling agents comprising a modified imidazoline or pyrimidine including an alkyl group (or unsaturated carbon chain) or of 10 to 22 carbon atoms, a polyamine, and ferric sulfate. The method of making the crosslinking agent features adding the polyamine after reaction of the other ingredients; unique gels formed with the crosslinking agent are particularly effective for LNG at very cold temperatures.