Fracturing Gas Injection for Coal Seam Recovery
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Solution Overview
Problem
Current methods for recovering hydrocarbons from geological formations, particularly coal seams, are inefficient in enhancing gas recovery due to limited fracture dilation and permeability, especially when the formation was not initially designed for commercial gas production.
Innovation Solution
A process involving the controlled introduction and adjustment of a non-participating gas, such as nitrogen, with a proppant into the formation to reach specific pressure and flow thresholds, followed by pressure relaxation, to effectively fracture and dilate existing fractures, thereby enhancing gas flow and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocarbon recovery methods are used in formations not originally designed for gas production, then existing production capabilities are maintained, but gas recovery efficiency remains limited due to insufficient fracture dilation and permeability
Solution Approach 1:
The process divides the formation treatment into multiple staged pressure thresholds (first threshold at 300-1000 scm, second threshold at 1000-3000 scm, third threshold at 3000-5000 scm), progressively creating and dilating fractures at different stages rather than applying one continuous high-pressure treatment
Solution Approach 2:
The method employs cyclic pressurization and pressure relaxation cycles, where pressure is increased to dilate fractures and then relaxed to allow proppant settlement and fracture stabilization, repeated multiple times to progressively enhance permeability
2Productivity
If high pressure is applied to create fractures in the formation, then fracture dilation and gas flow pathways are improved, but the complexity of controlling pressure thresholds and flow rates increases
Solution Approach 1:
The process incorporates continuous monitoring of injection rate, pressure, and flow thresholds with automatic adjustment mechanisms that modulate the injection rate based on real-time formation response, maintaining pressure within target ranges without requiring complex manual control
Solution Approach 2:
The method systematically varies key parameters including injection rate (from 300-5000 scm), pressure thresholds (progressive stages), and gas composition (non-participating gas selection) to optimize fracture creation and dilation while managing system complexity through defined parameter ranges
3Productivity
If multiple pressure thresholds are reached within a short time period (24 hours), then fracture dilation efficiency is enhanced, but the risk of formation damage and operational hazards increases
Solution Approach 1:
The process uses repeated cycles of pressurization to fracture dilation followed by pressure relaxation periods, allowing the formation to stabilize and proppant to settle between pressure increases, reducing the risk of formation damage while maintaining high productivity
Solution Approach 2:
The method introduces proppant material during the fracturing process to cushion and support the fractures before subsequent pressure cycles, preventing formation collapse and reducing damage from repeated pressurization events
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 process significantly increases gas flow rates by creating and propagating fractures, allowing for more efficient extraction of hydrocarbons like methane and shale gas from previously underutilized seams, improving overall hydrocarbon production.
Implementation Method 1
introducing a supply of fracturing non-participating gas to the formation at a rate of at least 300 standard cubic meters/minute
Implementation Method 2
pressurizing and permitting pressure relaxation of the seam a plurality of times in less than a twenty-four hour period
Implementation Method 3
the fracturing non-participating gas including a proppant in at least one of the stages of flow of the fracturing fluid
Implementation Method 4
pressurizing and permitting pressure relaxation of the seam a plurality of times in less than a twenty-four hour period
Data Source
AI summary
A process for fracturing a selected region of a formation including: introducing a supply of fracturing fluid to the region of the formation until a first threshold is reached, adjusting the flow of the fracturing fluid to the region of the formation to reach a second threshold, adjusting the flow of the fracturing fluid to the region of the formation to reach a third threshold and ceasing flow of the fracturing fluid to region of the formation, the fracturing fluid being a non-participating gas and including a proppant in at least one of the stages of flow of the fracturing fluid.