Structured Composite Proppants for High Stress Wells
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Solution Overview
Problem
Current proppant composites used in hydraulic fracturing and sand control applications are inadequate for high temperature and high pressure downhole conditions, as they tend to deform and lose compressive strength, leading to reduced fracture conductivity and productivity.
Innovation Solution
Structured composites with a particle size distribution of at least two modes, bound by a binder, which create a close-packed structure that enhances stress tolerance and maintains strength under extreme conditions, including the use of ultra lightweight particulates and density-modifying agents to achieve optimal specific gravity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultra lightweight proppants are used to reduce fluid velocity and increase fracture conductivity, then fracture conductivity is improved, but the proppants soften and lose compressive strength at high temperature and pressure conditions
Solution Approach 1:
The patent applies composite materials by combining ultra lightweight particulates (such as glass bubbles or hollow spheres) with a ceramic continuous phase matrix. This composite structure allows the proppant to maintain low density for improved fracture conductivity while the ceramic matrix provides the necessary compressive strength to withstand high temperature and pressure downhole conditions. The composite approach resolves the contradiction by integrating the beneficial properties of both materials.
Solution Approach 2:
The patent changes the physical and chemical parameters of the proppant material by using a ceramic continuous phase with high melting point and thermal stability. This parameter change enables the proppant to maintain its structural integrity and compressive strength at elevated temperatures (above 300°F) and pressures (greater than 5,000 psi) where conventional resin-coated proppants would deform and lose strength.
2Quantity of substance
If resin-coated proppants are used to achieve desired specific gravity, then specific gravity control is improved, but the proppants deform at elevated temperatures above 250°F under stress
Solution Approach 1:
The patent changes the material parameter from organic resin coating to inorganic ceramic continuous phase. This parameter change fundamentally alters the thermal stability characteristics, allowing the proppant to maintain structural integrity at temperatures above 250°F and even above 300°F where resin-coated proppants would deform. The ceramic matrix provides dimensional stability while allowing control of specific gravity through composition adjustment.
Solution Approach 2:
The patent replaces the short-lived resin coating that deforms at elevated temperatures with a long-lived ceramic continuous phase that maintains structural stability under downhole conditions. This substitution ensures the proppant can withstand the harsh thermal and mechanical environment of hydraulic fracturing operations without deforming or losing its load-bearing capability.
3Strength
If heavier proppants with higher ASG are used to withstand reservoir closure stress, then strength is improved, but proppant transport difficulty increases and propped fracture volume decreases
Solution Approach 1:
The patent employs composite materials with a lightweight particulate core (such as glass bubbles or hollow spheres) embedded in a ceramic continuous phase matrix. This composite structure achieves an optimal balance where the overall density is reduced for easier proppant transport and greater propped fracture volume, while the ceramic matrix provides sufficient compressive strength to withstand reservoir closure stresses. The composite approach allows decoupling of the density and strength properties that are coupled in conventional proppants.
Data Source
AI summary
A structured composite is comprised of particulates having particle size distribution of at least two modes and a binder. The particle size distribution is preferably bi-modal or tri-modal. The composite may further contain a density-modifying agent for modifying the density of the composite. The particulates are preferably substantially spherical and may be ultra lightweight (ULW) materials. The resulting composites exhibit the requisite strength to survive downhole imposed stresses and temperatures.