Reaction Driven Cracking for Subsurface Rock Fracturing
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Solution Overview
Problem
Current hydraulic fracture techniques in hydrocarbon reservoirs, geothermal systems, and carbon storage sites face inefficiencies due to large fracture spacing, limited fluid extraction, risks of induced seismicity, and reduced carbonation efficiency, as they struggle to achieve fracture spacings less than 1 meter and maintain permeability.
Innovation Solution
The method involves drilling holes to inject gaseous and aqueous fluids with non-toxic solutes that react to form supersaturated solutions, causing crystallization and compressive stresses, leading to fracture formation at the pore scale, mimicking natural processes like salt weathering to create dense fracture networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic fracture techniques are used to stimulate reservoirs, then fracture networks are created to enhance fluid flow, but fracture spacing exceeds one meter leading to limited extraction efficiency
Solution Approach 1:
The patent replaces the mechanical hydraulic fracturing system with a chemical system. Instead of using high-pressure fluid injection to mechanically fracture rock, the invention uses chemical reactions (acidification, thermal cracking, reaction-driven cracking) to create fractures. This substitution enables fracture spacing at the millimeter to micron scale, dramatically improving upon the meter-scale spacing achieved by hydraulic methods and thereby enhancing fluid extraction efficiency.
Solution Approach 2:
The patent changes the fundamental parameters of fracture creation from mechanical stress (hydraulic pressure) to chemical parameters (temperature, chemical concentration, reaction rates). By controlling chemical reaction conditions rather than mechanical pressure, the system achieves much finer fracture spacing and more uniform distribution, directly addressing the limitation of large fracture spacing in hydraulic fracturing.
2Productivity
If hydraulic fracture techniques are used, then fractures are created to improve permeability, but a few large fractures capture most fluid flow reducing overall efficiency
Solution Approach 1:
The patent applies segmentation by creating numerous small fractures distributed throughout the rock matrix rather than a few large fractures. Chemical reactions occur throughout the porous medium, generating many fine-scale fractures that collectively provide extensive flow pathways. This segmentation ensures more uniform fluid distribution across all fractures, preventing any single fracture from dominating flow and thereby improving overall extraction efficiency.
Solution Approach 2:
The patent implements local quality by creating fractures with appropriate size and distribution specific to local rock properties. Chemical reactions are injected at multiple locations and proceed according to local conditions, generating fractures tailored to each region's permeability and stress state. This localized approach ensures optimal fracture characteristics in different zones, maximizing overall fluid extraction rather than creating uniform large fractures.
3Productivity
If high water pressure is applied to fracture tight reservoirs, then permeability is enhanced, but induced seismicity and groundwater contamination risks increase
Solution Approach 1:
The patent replaces the high-pressure mechanical hydraulic fracturing system with chemical reaction systems that operate at much lower pressures. Acidification, thermal cracking, and reaction-driven cracking methods enhance permeability through chemical dissolution and mineral transformation rather than mechanical force, thereby eliminating the risks of induced seismicity and groundwater contamination associated with high-pressure injection while maintaining permeability enhancement benefits.
Solution Approach 2:
The patent converts potentially harmful high-pressure mechanical processes into beneficial low-pressure chemical processes. Instead of using force that can cause seismicity and contamination, the invention uses chemical reactions that naturally dissolve minerals and create fractures without mechanical stress. This transformation turns a harmful approach into a safe and effective method for permeability enhancement.
4Productivity
If in situ mineral carbonation is performed without reactive cracking, then CO2 is injected into reservoirs, but pore space fills and reactive surfaces armor reducing carbonation efficiency
Solution Approach 1:
The patent applies continuity of useful action by using reaction-driven cracking to continuously create new pore space and expose fresh reactive surfaces as carbonation progresses. As CO2 reacts with minerals and consumes pore space, the chemical reactions simultaneously generate new fractures and pores, maintaining continuous availability of reactive surfaces. This continuous regeneration of pore space ensures sustained high carbonation rates without the diminishing returns that occur when pore space fills and surfaces armor.
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 enhances permeability and reactive surface area, improving hydrocarbon extraction, geothermal energy production, and CO2 storage by achieving fracture spacings at the millimeter to micron scale, reducing seismic risks, and sustaining thermal energy and carbonation efficiency.
Implementation Method 1
fluids that are undersaturated in solid crystals are mixed and chemically react to form a combination that is strongly supersaturated... crystallization of solid minerals in pore space
Implementation Method 2
the combined solution will precipitate calcite or aragonite (CaCO3)... precipitate magnesite (MgCO3)... precipitate salt (NaCl)
Implementation Method 3
crystallization of solid minerals in pore space will lead to compressive stresses, and fracturing of rocks with crack spacing close to the pore scale
Data Source
AI summary
Methods and systems for causing reaction driven cracking in subsurface rock formations are disclosed. In some embodiments, the methods include the following: drilling one or more holes in a substantially porous subsurface rock formation, the one or more holes in fluid communication with pores in the subsurface rock formation; injecting in the pores via at least one of the holes one or more fluids, wherein the one or more fluids include a gas; and chemically reacting the one or more fluids within the pores thereby causing cracking in the substantially porous subsurface rock formation.