EGS Reservoir Interval Isolation for Targeted Fracture Stimulation
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Solution Overview
Problem
In Enhanced Geothermal Systems (EGS), a significant portion of the subterranean formation's energy potential remains untapped due to unstimulated regions with higher fracture initiation pressures, leading to inefficient power generation and high drilling and completion costs.
Innovation Solution
The method involves isolating selected subterranean open-hole intervals using temporary fracture sealants, high viscosity fluids, high pressure jet nozzles, high temperature inflatable or expandable packers, and scab liners to stimulate and seal fractures, allowing for targeted stimulation of unstimulated fractures without propagating sealed fractures, thereby reducing the number of wells required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water pressure is applied to create fractures in open-hole section, then fractures are created in regions with lowest fracture initiation pressure, but regions with higher fracture initiation pressure remain unstimulated
Solution Approach 1:
The open-hole section is divided into multiple isolated intervals using packers or temporary plugging agents. Each interval can be stimulated independently by applying water pressure separately, allowing fractures to be created in regions with higher fracture initiation pressure that would otherwise remain unstimulated.
Solution Approach 2:
Packers or temporary plugging agents are installed in advance to isolate specific intervals before fracture stimulation. This preliminary isolation enables controlled pressure application to target previously inaccessible regions with higher fracture initiation pressure.
2Ease of manufacture
If the number of wells is reduced to lower project cost, then drilling and completion costs decrease, but energy recovery from the formation is incomplete
Solution Approach 1:
By segmenting the wellbore into isolated intervals, each interval can be optimally stimulated for energy recovery. This allows a single well to effectively access and stimulate multiple previously inaccessible zones, reducing the total number of wells needed while maintaining or improving overall energy recovery.
Solution Approach 2:
The invention changes the pressure parameters applied to different intervals by isolating them. This enables selective stimulation of intervals with higher fracture initiation pressure, maximizing energy recovery from each well and reducing the number of wells required.
3Productivity
If fractures are stimulated in unisolated open-hole interval, then fractures propagate in orientation related to existing stresses, but only a small section is actually fractured
Solution Approach 1:
Isolating specific intervals ensures that fracture stimulation is confined to the desired location. This prevents unintended fracture propagation and allows precise control over which sections of the formation are fractured, improving both the precision and effectiveness of the stimulation process.
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 maximizes energy recovery by stimulating previously unaccessible fractures, reducing the number of wells needed, and lowering the overall cost of EGS projects by minimizing drilling and completion expenses.
Implementation Method 1
high pressure jet nozzles to stimulate and seal fractures
Implementation Method 2
high viscosity fluids to stimulate and seal fractures
Implementation Method 3
high temperature inflatable or expandable packers to isolate selected intervals
Data Source
AI summary
Systems and methods for maximizing energy recovery from a subterranean formation are herein disclosed. According to one embodiment, a selected subterranean open-hole interval is isolated and at least one fracture is stimulated in the isolated subterranean open-hole interval.