CBM Horizontal Well Shockwave Stimulation for Stable Fracturing
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Solution Overview
Problem
Current CBM extraction methods result in swift production decline and low yields due to ineffective fracturing and low permeability in coalbeds, exacerbated by complex geological structures and low permeability, leading to rapid fracture collapse and insufficient gas drainage.
Innovation Solution
A controlled shockwave-based stimulation method for CBM horizontal wells, involving targeted directional drilling and controlled shockwave operations to create fractures in specific zones, adjusting drilling locations based on fracturing and drainage affected zones, and dynamically adjusting shockwave intensity for optimal fracture propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fracturing methods are used in soft and low-permeability CBM wells, then fractures are generated to improve gas drainage, but the fractures collapse rapidly due to formation confining pressure and in-situ gas pressure, leading to swift production decline
Solution Approach 1:
The patent applies preliminary action by conducting formation evaluation and identifying the fracturing affected zone before implementing shockwave fracturing. This allows pre-planning of the fracturing process to target specific zones where fractures are most likely to be stable and effective, rather than applying shocks uniformly throughout the formation.
Solution Approach 2:
The patent changes the physical parameters of the fracturing process by using controlled shockwaves instead of conventional fluid injection. The shockwaves create fractures through mechanical vibration and stress concentration, allowing for better control over fracture location, size, and orientation while maintaining stability against collapse.
2Ease of manufacture
If shockwave fracturing is applied without prior formation evaluation, then the fracturing process can be implemented quickly, but the fracturing becomes ineffective and production remains low
Solution Approach 1:
The patent mandates preliminary formation evaluation and identification of the fracturing affected zone before shockwave fracturing is applied. This preliminary action ensures that the fracturing process targets the correct zones and uses appropriate parameters, thereby avoiding ineffective fracturing while maintaining operational efficiency.
Solution Approach 2:
The patent incorporates feedback mechanisms through monitoring of drilling parameters, gas content changes, and fracture response during the shockwave process. This feedback allows real-time adjustment of shockwave intensity and duration to optimize fracturing effectiveness while maintaining safety and controlling costs.
3Productivity
If multiple directional drilling sites are evaluated and shockwave operations are conducted at each, then the fracturing coverage is improved, but the time and resource consumption increases significantly
Solution Approach 1:
The patent applies preliminary formation evaluation and fracturing affected zone identification before shockwave operations. This allows prioritization of the most promising drilling sites and target zones, enabling selective shockwave application only where most effective, thereby reducing overall time and resource consumption while maintaining adequate fracturing coverage.
Solution Approach 2:
The patent applies local quality by tailoring shockwave parameters and drilling targets to specific local conditions at each site. Rather than applying uniform treatment to all sites, the method adjusts shockwave intensity, duration, and direction based on local formation characteristics, geology, and previously identified fracturing affected zones, optimizing effectiveness while minimizing unnecessary operations.
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
Enhances CBM production by creating effective fractures that increase permeability and gas mobility, optimizing drilling efficiency, and ensuring targeted fracture stimulation without disrupting existing drainage, thereby improving overall CBM well productivity.
Implementation Method 1
delivering, after the drilling, a controlled shockwave generation device through a drilling rig to a stratum where a fracturing sand or fracturing fluid is detected
Implementation Method 2
The shock waves propagate through the fracturing fluid within the fractures to alter coalbed pressure distribution and break barriers between fractures
Data Source
AI summary
A controlled shockwave-based stimulation method for a coalbed methane (CBM) horizontal well includes: S1: selecting a group of upward directional drilling sites in an underground roadway of a service mine for a horizontal well, where directional drilling target locations are coalbeds respectively directly opposite to horizontal well perforation points and at multiple distances from the horizontal well; S2: drilling for an A m target location, and determining whether the target location is within a fracturing affected zone and a drainage affected zone of the horizontal well; conducting a controlled shockwave operation if the drilling target location is within the fracturing affected zone; and S3: drilling at each of the horizontal well perforations according to the step S2 and performing a determination until target locations within the fracturing affected zone are found for all the horizontal well perforations; and conducting a controlled shockwave operation.