Crosslinked Endothermic Fluid for Lower-Pressure Formation Fracturing
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Solution Overview
Problem
Unconventional reservoirs with low permeability and porosity require high pressures and large fluid volumes for hydraulic fracturing, increasing costs and material needs.
Innovation Solution
A crosslinked endothermic fluid composition containing ammonium chloride, which reacts with subsurface formation fluids to induce thermal shock, reducing the compressive strength and Poisson's ratio, thereby decreasing the formation breakdown pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure and large fluid volumes are used for hydraulic fracturing in unconventional reservoirs, then fractures can be formed to enable fluid production, but the cost and material requirements increase substantially
Solution Approach 1:
The patent changes the physical-chemical parameters of the formation by introducing an endothermic composition that undergoes a temperature change reaction. This transforms the thermal state of the formation, creating thermal stress that reduces compressive strength and Poisson's ratio, thereby enabling fracturing at lower pressures and fluid volumes
Solution Approach 2:
The endothermic composition undergoes a phase transition or chemical reaction that absorbs heat and decreases temperature. This phase change process creates thermal shock in the formation, inducing fractures without requiring conventional high-pressure fluid injection
2Stress or pressure
If the compressive strength and Poisson's ratio of the subsurface formation are decreased through thermal shock, then the formation breakdown pressure decreases, but the complexity of the fracturing process increases
Solution Approach 1:
The endothermic composition acts as an intermediary substance that mediates between the fracturing operation and the formation. It is injected into the formation, undergoes an endothermic reaction to create thermal shock, and then facilitates fracture initiation at reduced pressures, simplifying the overall process despite the chemical complexity
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 method reduces the fluid and pressure requirements for hydraulic fracturing, leading to cost and material savings by inducing fractures with thermal shock.
Implementation Method 1
the ammonium chloride may react, decreasing the temperature of the subsurface formation, releasing ammonia, and thereby inducing thermal shock
Implementation Method 2
the crosslinks in the crosslinked endothermic fluid compound may at least partially break due to the increased subsurface formation temperature, thereby releasing the ammonium chloride
Data Source
AI summary
A crosslinked endothermic fluid composition may comprise an aqueous solution; ammonium chloride; a polymer; and a crosslinker. A method of thermally shocking a subsurface formation may comprise introducing the crosslinked endothermic fluid composition into a wellbore fluidly connected to the subsurface formation; exposing the crosslinked endothermic fluid composition to the subsurface formation, such that a temperature of the subsurface formation at least partially breaks a crosslink of the crosslinked endothermic fluid composition and exposes at least a portion of the ammonium chloride; reacting the ammonium chloride in the crosslinked endothermic fluid composition with fluids of the subsurface formation, thereby decreasing a temperature of the subsurface formation and producing ammonia; and thermally shocking the subsurface formation via the decreased temperature and produced ammonia, thereby inducing one or more fractures in the subsurface formation.