Alternating Fluid Stages for Fracture Network Complexity
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Solution Overview
Problem
Traditional hydraulic fracturing methods struggle to effectively enhance fracture network complexity in subterranean formations, particularly in low-permeability formations like shale, leading to reduced hydrocarbon recovery due to limited fracture growth and interference from complex bedding planes.
Innovation Solution
The use of a multistage fracturing technique involving alternating high-viscosity pad fluids and low-viscosity micro-proppant fluids to create and extend main and branch fractures, respectively, while minimizing leakoff and stress shadowing, thereby enhancing fracture network complexity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional hydraulic fracturing methods are used, then fractures can be created in subterranean formations, but fracture network complexity is limited due to interference from complex bedding planes and stress shadowing effects
Solution Approach 1:
The treatment is divided into multiple stages with alternating pad fluids and proppant fluids. Each stage creates or extends specific fractures (main fractures from pad fluid, branch fractures from proppant fluid), segmenting the overall fracturing process to systematically build complex fracture networks while managing stress shadowing effects between different fracture types.
Solution Approach 2:
Different fluid types are applied to different locations and purposes within the formation. High-viscosity pad fluids are used to create and extend main fractures in specific zones, while low-viscosity proppant fluids are used to create branch fractures in other areas, giving each region of the treatment different properties optimized for its specific function.
2Device complexity
If proppant particulates are deposited into fractures to keep them open, then fracture conductivity is improved, but fracture complexity is reduced due to proppant pack formation
Solution Approach 1:
The treatment sequence segments proppant placement into specific stages following pad fluid fracture creation. By alternating between pad fluids (creating fractures) and proppant fluids (placing proppant in branch fractures), the system maintains fracture network complexity while ensuring critical fractures are propped for conductivity.
Solution Approach 2:
Pad fluids are injected first to create and extend main fractures before proppant fluids are introduced. This preliminary action of creating the fracture geometry without proppant allows for more complex fracture networks to form, after which proppant is placed in strategic locations to maintain conductivity without过度 complicating the overall network structure.
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 network complexity, leading to improved hydrocarbon recovery by maintaining open fractures and increasing the surface area for fluid flow, thus enhancing productivity in both near-wellbore and far-field regions.
Implementation Method 1
a treatment fluid, sometimes called a carrier fluid in cases where the treatment fluid carries particulates entrained therein, is pumped into a portion of a subterranean formation (which may also be referred to herein simply as a 'formation') above a fracture gradient sufficient to break down the formation and create one or more fractures therein
Implementation Method 2
a low-viscosity micro-proppant fluid that creates or extends at least a first branch fracture extending from the first main fracture
Implementation Method 3
The particulate solids, known as 'proppant particulates' or simply 'proppant' serve to prevent the fractures from fully closing once the hydraulic pressure is removed
Implementation Method 4
By keeping the fractures from fully closing, the proppant particulates form a proppant pack having interstitial spaces that act as conductive paths through which fluids produced from the formation may flow
Data Source
AI summary
Methods including creating or extending a first main fracture with a pad fluid into a subterranean formation, wherein the pad fluid is a high-viscosity fluid; alternatingly introducing a micro-proppant fluid with the pad fluid, wherein the micro-proppant fluid is a low-viscosity fluid comprising micro-sized proppant particulates; creating or extending a first branch fracture extending from the first main fracture with the alternatingly introduced micro-proppant fluid, whereby at least a portion of the micro-sized proppant particulates enter into the first branch fracture and form at least a partial monolayer of micro-sized proppant particulates therein; and introducing a macro-proppant fluid through the first opening at a second flow rate, wherein the macro-proppant fluid is a low-viscosity fluid comprising macro-sized proppant particulates, and whereby at least a portion of the macro-sized proppant particulates enter into the first main fracture and form a proppant pack therein.