Enhanced Geothermal Interval Isolation for Deeper Fracture Stimulation
Find Innovative SolutionsGenerate Solutions
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 low efficiency and high costs associated with drilling and completing wells.
Innovation Solution
The method involves isolating selected subterranean open-hole intervals and stimulating fractures using temporary fracture sealants, high viscosity fluids, high temperature inflatable or expandable packers, and scab liners to selectively stimulate and seal fractures, thereby maximizing energy recovery without the need for continuous drilling rig presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water pressure is used to open fractures in the open-hole section, then fractures are created in the section with lowest fracture initiation pressure, but only a relatively small section is actually fractured and deeper regions with higher fracture initiation pressures remain unstimulated
Solution Approach 1:
The open-hole section is divided into multiple isolated intervals using packers and bridge plugs. Each interval can be independently stimulated, allowing systematic access to different fracture initiation pressure zones along the wellbore, thereby increasing the proportion of the formation that can be effectively stimulated.
Solution Approach 2:
The packers and bridge plugs are installed in advance to isolate specific intervals before stimulation. This preliminary isolation enables controlled pressure application to target deeper zones with higher fracture initiation pressures that would otherwise remain inaccessible, maximizing the stimulated section proportion.
2Productivity
If multiple wells are drilled to access different fracture zones, then more energy sources can be tapped, but the cost of drilling and completing wells increases significantly
Solution Approach 1:
A single wellbore is designed to serve multiple functions by isolating and stimulating multiple fracture zones at different depths. The same well infrastructure (drilling, completion, production equipment) is used to access and produce from multiple previously separate zones, eliminating the need for multiple separate wells and significantly reducing project costs.
3Productivity
If the open-hole section is isolated into multiple intervals, then each interval can be independently stimulated, but the device complexity and isolation requirements increase
Solution Approach 1:
Bridge plugs are used as intermediary elements to create hydraulic isolation between intervals. These plugs can be set and retrieved relatively easily compared to permanent cement barriers, providing the necessary isolation for independent interval stimulation while maintaining operational flexibility and reducing overall system complexity.
Solution Approach 2:
The system uses self-contained packers and bridge plugs that can be deployed and retrieved using standard well intervention equipment. The isolation mechanism is self-sufficient, requiring no external support systems, which simplifies the overall isolation system while enabling effective multi-interval stimulation.
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 allows for more efficient energy recovery by stimulating previously unaccessed fractures, reducing the number of wells required, and lowering the overall project cost by optimizing the stimulation and isolation of fracture networks within the subterranean formation.
Implementation Method 1
stimulating fractures using temporary fracture sealants, high viscosity fluids
Implementation Method 2
isolating selected subterranean open-hole intervals
Implementation Method 3
high temperature inflatable or expandable packers
Implementation Method 4
expandable packers
Implementation Method 5
Water pressure opens a network of fractures in the open-hole section of the subterranean formation having the lowest fracture initiation pressure
Implementation Method 6
pumping water from the surface down into the well. Water pressure opens a network of fractures
Implementation Method 7
The hot water or heat from the formation is produced from one or more production wells some distance away from the injection well and used for generating electricity
Implementation Method 8
used for generating electricity
Data Source
Figure 1
Figure 2
Figure 3
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.