Proppant Pillars via Zeta Potential Alteration for Fracture Conductivity
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Solution Overview
Problem
Existing methods for fracturing subterranean formations face challenges in maintaining high conductivity due to proppant compaction and embedment, leading to reduced fracture conductivity under pressure, especially when using low-strength or non-spherical proppants.
Innovation Solution
The use of zeta potential altering chemistries and aggregating compositions to coat proppants, allowing them to aggregate into pillars within fractures, thereby reducing the need for high proppant concentrations and enhancing fracture conductivity by creating stable, conductive pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high concentrations of proppant are deposited in fractures to keep them opened, then fracture support is improved, but proppant compaction and embedment increase causing decreased fracture conductivity
Solution Approach 1:
The proppant is segmented into discrete pillars rather than continuous packs. The method creates isolated proppant pillars spaced apart within the fracture, transforming the continuous proppant pack into discrete structural elements that support the fracture while maintaining flow paths between them.
Solution Approach 2:
The invention applies different proppant concentrations locally - high concentration at pillar locations for structural support, and low or zero concentration in the spaces between pillars for fluid flow. This local differentiation allows simultaneous achievement of fracture support and conductivity.
2Reliability
If low volume of proppant is deposited to create partial monolayer for high conductivity, then fracture conductivity is improved, but fracture support under high pressure deteriorates
Solution Approach 1:
The proppant is arranged as discrete pillars rather than continuous packs. This segmentation allows low overall proppant volume while maintaining structural support at critical pillar locations, with spaces between pillars providing flow paths.
Solution Approach 2:
The invention transitions from two-dimensional proppant packs (filling the fracture plane) to three-dimensional proppant pillars (vertical columns within the fracture). This dimensional change allows support with reduced proppant volume by utilizing the vertical dimension for structural integrity.
3Reliability
If proppants are placed far from each other to reduce compaction, then fracture conductivity is improved, but fracture support and pillar stability worsen
Solution Approach 1:
The invention uses composite proppant structures combining multiple materials - such as coated proppants, proppant mixtures, or proppant combined with fibrous materials - to create pillars that are both stable and conductive. The composite nature provides both structural integrity and flow pathways.
Solution Approach 2:
The invention employs spherical or near-spherical proppant particles to form pillars. The spherical geometry reduces stress concentration points compared to angular particles, improving pillar stability while maintaining flow paths between pillars.
4Reliability
If proppant concentration is reduced to prevent embedment, then fracture conductivity is improved, but proppant pillar strength deteriorates
Solution Approach 1:
The invention uses composite proppant structures with enhanced strength properties - such as resin-coated proppants, proppant mixtures including high-strength materials, or proppant combined with fibrous reinforcements - to maintain pillar strength at reduced concentrations.
Solution Approach 2:
The invention employs spherical or near-spherical proppant particles to form pillars. The spherical geometry reduces stress concentration points compared to angular particles, improving pillar stability while maintaining flow paths between pillars.
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 increases fracture conductivity and maintains pillar strength, preventing collapse and erosion, even under high production pressures, while also capturing fines to maintain porosity over time.
Implementation Method 1
The use of zeta potential altering chemistries and aggregating compositions to coat proppants, allowing them to aggregate into pillars within fractures
Implementation Method 2
The zeta altering or aggregating composition coats or partially coats the proppant particles such as sand changing the zeta potential or aggregating propensity of the proppant particles causing the particles to aggregate or agglomerate into distinct pillars
Data Source
AI summary
Methods for forming proppant pillars in a formation during formation fracturing include include periods of pumping a first fracturing fluid including a proppant and an aggregating composition including a reaction product of a phosphate compound or a plurality of phosphate and an amine, periods of pumping a second fracturing fluid excluding a proppant and an aggregating composition including a reaction product of a phosphate compound and periods of pumping a third fracturing fluid including an aggregating composition including a reaction product of a phosphate compound, where the pumping of the three fracturing fluids may be in any order and may involve continuous pumping, pulse pumping, or non-continuous pumping.