Acoustic Telemetry Nodes for Downhole Fracture Geometry Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for monitoring hydraulic fracture geometry in subsurface formations are limited by signal attenuation and interference, requiring expensive dedicated monitoring wells or surface geophones that are prone to errors and operational challenges.
Innovation Solution
An electro-acoustic telemetry system with communications nodes spaced along the wellbore that transmit acoustic signals indicative of elastic waves, allowing for wireless data transmission and mapping of fracture geometry without the need for an offset well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface geophones or dedicated monitoring wells are used to detect fracture geometry, then measurement capability is provided, but device complexity and operational cost increase significantly
Solution Approach 1:
The patent uses the wellbore itself as an intermediary medium to transmit acoustic signals from the fracture zone to surface detectors. Instead of placing detectors in the fracture zone or using dedicated monitoring wells, the system transmits acoustic signals through the wellbore fluid or formation, using the existing well infrastructure as the transmission path. This eliminates the need for complex downhole detector systems while maintaining measurement capability.
Solution Approach 2:
The patent creates an acoustic copy or representation of the fracture geometry by detecting elastic waves generated during hydraulic fracturing. Rather than directly measuring fracture geometry with complex downhole sensors, the system uses acoustic wave patterns that replicate the fracture characteristics, allowing surface-based detection of subsurface fracture geometry through signal analysis.
2Reliability
If multiple detectors are placed in the wellbore to overcome signal attenuation, then measurement reliability improves, but device complexity and cost increase
Solution Approach 1:
Instead of placing multiple detectors downhole to capture attenuated signals, the patent inverts the approach by using a single or minimal detector array at the surface and transmitting signals upward through the wellbore. This reverses the traditional detection geometry, allowing signals to be generated near the fracture zone and propagated to surface detectors where no attenuation from downhole placement is an issue.
Solution Approach 2:
The patent extracts the detection function from the downhole environment and relocates it to the surface. By removing detectors from the complex, high-attenuation downhole environment and placing them at the surface where signal quality is preserved, the system achieves reliable detection without requiring multiple downhole detectors or complex downhole detector arrays.
3Ease of operation
If acoustic signals are transmitted through the wellbore for wireless data transmission, then operational simplicity improves, but signal attenuation and interference increase
Solution Approach 1:
The patent applies preliminary signal processing and conditioning before transmission through the wellbore. By pre-processing acoustic signals, filtering noise, and optimizing signal characteristics before they enter the wellbore transmission medium, the system compensates for anticipated attenuation and interference, ensuring reliable signal propagation despite the challenging transmission environment.
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
Enables high-speed data transmission and accurate mapping of subsurface fractures, improving the efficiency of hydrocarbon recovery by overcoming previous limitations in signal detection and operational complexity.
Implementation Method 1
acoustic signals indicative of elastic waves caused by movement of rock within the subsurface formation
Implementation Method 2
The transducers are secured to the wellbore and detect the elastic waves
Data Source
AI summary
An electro-acoustic system for downhole telemetry employs a series of communications nodes spaced along a string of casing within a wellbore. The nodes allow wireless communication between transceivers residing within the communications nodes and a receiver at the surface. The transceivers provide node-to-node communication of data indicating elastic waves generated as a result of the formation of subsurface fractures. The data is processed which generates a map of fracture geometry. A method of evaluating fracture geometry in a subsurface formation uses a plurality of data transmission nodes situated along the casing string which send signals to a receiver at the surface. The signals are analyzed which generates a subsurface map.