Proppant Distribution in Hydraulic Fractures
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Solution Overview
Problem
Hydraulic fracturing in hydrocarbon-producing wells often faces challenges in maintaining fracture openness and ensuring effective hydrocarbon flow due to the closure of fractures under stress, which limits the efficiency of hydrocarbon extraction.
Innovation Solution
The use of a sequence of treatment fluids, including pad fluids, low viscosity fluids with micro-proppants, and high viscosity fluids with bridging agents, to create and extend fracture networks, allowing for the formation of full and partial proppant packs that maintain fracture openness and enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fractures are created in hydrocarbon-bearing formations to enable hydrocarbon flow, then hydrocarbon production is improved, but the fractures close under stress reducing effectiveness
Solution Approach 1:
The patent applies local quality by creating different types of proppant packs with varying properties at different locations within the fracture network. Full proppant packs are formed in some fracture regions to provide strong mechanical support and maintain openness, while partial proppant packs are created in other regions to optimize fluid flow conductivity. This spatial differentiation of proppant pack characteristics allows simultaneous optimization of fracture stability and hydrocarbon production.
Solution Approach 2:
The patent employs composite materials by combining multiple proppant types with different physical properties within the same fracture system. The proppant mixture includes particles of varying sizes, shapes, and materials that work together to create both full and partial proppant packs. This composite approach enables the fracture system to exhibit both mechanical strength for maintaining openness and fluid flow conductivity for hydrocarbon production.
2Reliability
If proppant is injected to maintain fracture openness, then fracture stability is improved, but proppant distribution uniformity deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the fracture network into distinct zones with different proppant pack configurations. Full proppant packs are segmented into specific fracture regions where mechanical support is most critical, while partial proppant packs are placed in other regions where fluid flow is prioritized. This zonal segmentation allows targeted proppant placement that achieves both fracture stability and acceptable distribution uniformity.
Solution Approach 2:
The patent utilizes parameter changes by varying proppant characteristics such as particle size, shape, and material composition to achieve different proppant pack types. By adjusting these parameters, the system creates full proppant packs with high density and mechanical strength in some zones, and partial proppant packs with lower density and higher conductivity in other zones, thereby achieving uniform distribution through controlled parameter variation.
3Productivity
If treatment fluids are used to create fracture networks, then fracture conductivity is improved, but fluid viscosity variations complicate flow control
Solution Approach 1:
The patent applies dynamics by using treatment fluids with varying viscosities at different stages of the fracturing process. Lower viscosity fluids are used initially to create and extend fracture networks, while higher viscosity fluids are introduced later to maintain fracture openness and ensure proppant placement. This dynamic adjustment of fluid properties allows effective flow control throughout the complex multi-stage treatment process.
Solution Approach 2:
The patent employs periodic action by implementing multiple treatment fluid injections in sequence, with each injection serving a specific function. The process alternates between creating fractures, maintaining openness, and optimizing conductivity through periodic fluid delivery. This staged approach manages the complexity of fluid flow control by breaking down the overall process into manageable, function-specific phases.
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 maintains fracture openness and increases hydrocarbon flow conductivity, leading to improved hydrocarbon production by creating a network of propped fractures with varying porosity and permeability, optimizing fluid flow through the fracture system.
Implementation Method 1
allowing the first proppant particulate to gravitationally migrate into a portion of the at least one fracture
Implementation Method 2
a fracturing fluid is pumped at an elevated pressure from a wellbore into adjacent hydrocarbon-bearing subterranean formations. The pumped fracturing fluid splits or 'fractures' the rock formation along veins or planes
Implementation Method 3
The proppant is left behind to prevent the fractures from closing onto themselves due to the weight and stresses within the formation. Accordingly, the proppant 'props' or supports the fractures to remain open
Implementation Method 4
the proppant remains permeable to hydrocarbon fluid flow since they form a packed bed of particles with interstitial void space connectivity
Data Source
AI summary
A variety of systems, methods, and compositions are disclosed, including, a method for treating a subterranean formation, the method comprising: injecting a pad fluid into the subterranean formation at a pressure sufficient to create at least one fracture in the subterranean formation; injecting a first treatment fluid into the at least one fracture, wherein the first treatment fluid comprises: an aqueous base fluid, and a first proppant particulate; allowing the first proppant particulate to gravitationally migrate into a portion of the at least one fracture; injecting a second treatment fluid into the at least one fracture, wherein the second treatment fluid comprises: a suspension base fluid comprising a viscosity of about 50 cP to about 10,000 cP, and a second proppant particulate; and allowing the fracture to close, thereby forming a full proppant pack and a partial proppant pack in the at least one fracture.