Micro Proppants for Dendritic Fracture Stimulation
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Solution Overview
Problem
In low permeability formations like shale, hydraulic fracturing stimulation forms primary and induced dendritic fractures, but typical proppants used are too large to invade and prop open the small, branching dendritic fractures, leading to incomplete fracture network access and reduced resource recovery.
Innovation Solution
The use of micro proppants smaller than 100 mesh, generated either downhole or pre-formed, that are specifically sized to fit within the transverse dimension of dendritic fractures under fracturing pressure, along with a fracturing fluid system that includes a gel producing apparatus and proppant precursors activated by pH changes or other additives to ensure effective propping of both dendritic and natural fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical proppants (100-12 mesh) are used in hydraulic fracturing, then the primary fractures in the near field are effectively propped open, but the induced dendritic fractures in the far field cannot be invaded or propped due to their small size
Solution Approach 1:
The proppant system is segmented into multiple size categories: larger proppants (100-12 mesh) for primary near-field fractures and micro proppants (<100 mesh, particularly 200-325 mesh) for dendritic far-field fractures. This segmentation allows each proppant size to be optimized for specific fracture types, resolving the contradiction between propping effectiveness and adaptability to different fracture geometries.
Solution Approach 2:
Different proppant sizes are deployed to different spatial locations within the fracture network. Larger proppants are retained in the near-field primary fractures where they provide structural support, while micro proppants are transported to and retained in the far-field dendritic fractures. This local quality differentiation ensures optimal propping effectiveness in each zone while maintaining overall system adaptability.
2Strength
If larger proppants are used to ensure structural support in primary fractures, then near field fracture propping is effective, but far field dendritic fractures remain inaccessible
Solution Approach 1:
The proppant population is segmented by size to simultaneously satisfy strength requirements in near-field fractures and penetration requirements for far-field fractures. Larger proppants provide the necessary structural strength and load-bearing capacity in primary fractures, while smaller micro proppants can penetrate deeper into the fracture network to reach and prop dendritic fractures, thus resolving the contradiction between strength and penetration depth.
Solution Approach 2:
The proppant size parameter is changed across the fracture network to optimize both strength and penetration. By using a distribution of proppant sizes rather than a single size, the system achieves adequate structural support from larger proppants while allowing smaller proppants to penetrate deeper distances into the fracture system, effectively resolving the trade-off between these two parameters.
3Adaptability or versatility
If micro proppants smaller than 100 mesh are used to invade dendritic fractures, then far field fracture access is improved, but the ability to provide structural support compared to larger proppants is reduced
Solution Approach 1:
The proppant system is segmented into functional groups: micro proppants (<100 mesh) provide adaptability and penetration into dendritic fractures, while larger proppants (100-12 mesh) provide structural support and load-bearing capacity. This segmentation allows each proppant size to excel at its specific function, resolving the contradiction between adaptability to small fractures and overall structural strength.
Solution Approach 2:
The system merges multiple proppant size classes into a single fracturing treatment, combining the advantages of both large and small proppants. The larger proppants provide the necessary structural framework and load-bearing capacity, while the micro proppants fill in the dendritic fracture network, creating a composite propping system that achieves both strength and adaptability simultaneously.
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 effectively keeps the induced and linked natural fractures open, enhancing fluid recovery by ensuring that the smaller micro proppants can invade and prop open the small dendritic fractures, thereby improving the connectivity of the fracture network and increasing resource extraction efficiency.
Implementation Method 1
a gel producing apparatus
Implementation Method 2
proppant precursors activated by pH changes
Data Source
AI summary
A subterranean zone surrounding a well bore is fractured with a fracturing fluid. Micro proppant of 200 mesh or smaller is pumped into far field fractures of the subterranean zone and props the far field fractures open.