Fly Ash Microspheres Proppant Grading Fracture Conductivity
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Solution Overview
Problem
Low permeability subterranean formations, such as shale reservoirs and tight-gas sands, require enhanced fracture network complexity to increase hydrocarbon recovery, as traditional hydraulic fracturing methods struggle to maintain open fractures and improve fluid flow.
Innovation Solution
The use of fly ash microspheres and larger proppant particulates is introduced into the subterranean formation to create and maintain open fractures, with fly ash microspheres forming a partial monolayer in microfractures and proppant particulates forming a partial monolayer in main fractures, enhancing fracture network complexity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hydraulic fracturing methods are used, then fractures can be created in the formation, but the fractures cannot be maintained open and fluid flow is not improved
Solution Approach 1:
The patent applies different sizes of proppant particulates to different locations within the fracture network. Larger proppant particulates (e.g., 20-100 mesh) are placed in main fractures to provide structural support, while smaller proppant particulates (e.g., 100-200 mesh) are placed in microfractures to maintain openness. This localized differentiation ensures that each region of the fracture network receives the appropriate proppant size for its specific function, thereby maintaining fracture openness and improving fluid flow throughout the entire network.
Solution Approach 2:
The patent segments the fracture network into distinct regions: main fractures and microfractures. By introducing a graded distribution of proppant particulates with different size ranges into these segmented regions, the system addresses the unique requirements of each fracture type. This segmentation allows for optimized proppant placement that maintains both large-scale and small-scale fracture openness, resolving the contradiction between maintaining fracture integrity and enabling fluid flow.
2Reliability
If proppant particulates are introduced to keep fractures open, then fracture conductivity is improved, but the complexity of the fracture network is reduced
Solution Approach 1:
The patent introduces proppant particulates with specific size ranges into specific regions of the fracture network. Larger proppant particulates are concentrated in main fractures where high conductivity is needed, while smaller proppant particulates are introduced into microfractures to preserve their complexity and branching structure. This localized approach maintains fracture conductivity in critical areas while preserving the overall network complexity that enhances hydrocarbon recovery.
Solution Approach 2:
The patent changes the parameter of proppant particulate size distribution throughout the fracture network. By using a graded distribution where proppant size varies from region to region (larger in main fractures, smaller in microfractures), the system optimizes conductivity where needed while maintaining network complexity elsewhere. This parameter variation resolves the contradiction between improving conductivity and preserving fracture network complexity.
3Ease of manufacture
If uniform proppant size is used throughout the fracture network, then the process is simplified, but permeability and productivity of low permeability formations are not significantly increased
Solution Approach 1:
The patent implements a localized quality approach by using different proppant size ranges in different regions of the fracture network. Rather than using a uniform proppant size throughout, the system introduces larger proppant particulates (e.g., 20-100 mesh) into main fractures and smaller proppant particulates (e.g., 100-200 mesh) into microfractures. This differentiation significantly increases permeability and productivity of low permeability formations by optimizing proppant placement in each region, while the overall process remains relatively simple through sequential or simultaneous injection methods.
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 the permeability and productivity of low permeability formations by maintaining open fractures and creating conductive paths for fluid flow, thereby enhancing hydrocarbon recovery.
Implementation Method 1
fly ash microspheres forming a partial monolayer in microfractures
Implementation Method 2
proppant particulates forming a partial monolayer in main fractures
Implementation Method 3
pumped into a portion of a subterranean formation above a fracture gradient sufficient to break down the formation and create one or more fractures
Data Source
AI summary
Treatment fluids including a base fluid; and fly ash microspheres, wherein the fly ash microspheres are of a material selected from the group consisting of Class C fly ash, Class F fly ash, and any combination thereof, wherein the fly ash microspheres have a diameter in the range of from about 0.1μηη to about 150μηη, and wherein the fly ash microspheres are present in the treatment fluid in an amount in the range of from about 0.001 ppg to about 1 ppg of the treatment fluid.