Exothermic Chemical Fracturing for Low Permeability Reservoirs
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Solution Overview
Problem
Current methods for fracturing subterranean formations, such as hydraulic fracturing and the use of explosives, are costly and inefficient for maximizing oil and gas recovery from low permeability reservoirs like shale and tight-gas formations, as they often result in insufficient fracture complexity and can damage the formations.
Innovation Solution
A method involving a mixture of ammonium compounds, oxidizing agents like nitrites, and bisulfate salts that undergo exothermic reactions to generate large volumes of gas and heat, creating new or extending existing fractures by overcoming confining pressures within the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic fracturing is used to create fractures in low permeability reservoirs, then some fracture network is created, but the extent and complexity of the fracture patterns is insufficient to maximise oil recovery
Solution Approach 1:
The patent changes the physical parameters of the fracturing process by using exothermic chemical reactions to generate extreme temperatures and pressures in situ. This creates more complex and extensive fracture patterns compared to conventional hydraulic fracturing, thereby improving oil recovery from low permeability reservoirs.
Solution Approach 2:
The patent replaces the mechanical hydraulic fracturing system with a chemical reaction system. Instead of pumping high-pressure fluids to create fractures, exothermic chemical reactions are used to generate the necessary pressure and heat to create and extend fracture networks, achieving greater complexity and effectiveness.
2Ease of manufacture
If hydraulic fracturing fluids are used to create fractures, then fractures are created, but the fluids are costly and can damage formations
Solution Approach 1:
The patent uses inexpensive chemical reactants that are consumed in situ to generate the fracturing effect. These disposable chemical materials replace costly and potentially damaging hydraulic fracturing fluids, providing an economical and formation-friendly alternative for creating fracture networks.
Solution Approach 2:
The patent converts the potential harm of using chemicals into a benefit by selecting chemical reactions that produce useful effects (extreme heat and pressure for fracturing) while minimizing formation damage. The chemical energy is transformed into mechanical energy for fracture creation, eliminating the need for harmful fracturing fluids.
3Productivity
If explosives are used to create multiple radial fractures, then extensive fracturing is achieved, but large compacted zones of rock are created from which fluids cannot escape
Solution Approach 1:
The patent changes the pressure generation mechanism from explosive mechanical force to controlled exothermic chemical reaction. This produces more uniform pressure distribution that creates fractures without the severe compaction zones associated with explosives, maintaining hydrocarbon escape pathways and improving productivity.
Solution Approach 2:
The patent replaces the explosive mechanical fracturing system with a chemical reaction system. The gradual heat and pressure generation from exothermic reactions creates fractures without the shock waves and compaction zones that block fluid flow, thereby maintaining hydrocarbon escape capability while achieving extensive fracturing.
4Quantity of substance
If known chemical systems are used to generate heat and gas in downhole operations, then some gas is produced, but the amount of gas is limited and insufficient to overcome confining pressure
Solution Approach 1:
The patent uses composite chemical systems combining multiple reactants (ammonium compounds, oxidizing agents, and acids) that work synergistically to produce large volumes of gas and extreme heat. This composite approach overcomes the limitations of single-chemical systems and generates sufficient pressure to overcome formation confining pressure.
Solution Approach 2:
The patent dramatically changes the gas generation parameters by selecting chemical reactions with very high gas evolution rates and volumes. The exothermic reactions produce sufficient gas pressure to overcome confining pressure and create fractures, solving the limitation of known chemical systems that produce insufficient gas volumes.
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 approach significantly increases gas production per mole of reactants, effectively fracturing the formation with non-toxic by-products, enhancing hydrocarbon production and fracture complexity while minimizing formation damage.
Implementation Method 1
a mixture of chemicals which are arranged to undergo an exothermic reaction and/or produce large quantities of gas underground
Implementation Method 2
the combination of heat and gas pressure can be used to treat, for example fracture, the formation
Implementation Method 3
a large amount of gas needs to be generated to produce a pressure sufficient to overcome the confining pressure within the wellbore
Data Source
AI summary
A method of treating a subterranean formation by contacting the formation with the following: (a) an ammonium compound; (b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and (c) one or more acids, at least one of which is a bisulfate salt.