Aqueous Curable Resin Stabilizes Coal Seam Laminae
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Solution Overview
Problem
Coal seam wellbores face instability due to erosion of formation laminae when exposed to freshwater, leading to reduced methane production and frequent remedial actions, as traditional clay and fines stabilizers are ineffective in preventing swelling and erosion.
Innovation Solution
Introducing a treatment fluid comprising an aqueous base fluid and an aqueous curable resin into the wellbore, which penetrates into the formation laminae, cures to stabilize them, and maintains pressure to prevent freshwater influx, thereby stabilizing the laminae and facilitating methane extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional clay and fines stabilizers are used to stabilize formation laminae, then ion exchange is achieved, but physical bonding or cohesion is insufficient to overcome swelling caused by freshwater exposure
Solution Approach 1:
The patent combines multiple stabilizing mechanisms (ion exchange, physical bonding, and cohesion) into a composite treatment fluid system. The treatment fluid contains both clay/fines stabilizers for ion exchange and additional agents that provide physical bonding and cohesive forces to counteract swelling, creating a multi-functional stabilization system that addresses the limitations of traditional single-mechanism approaches.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the treatment fluid to enhance its stabilizing capabilities. This includes adjusting the composition to provide both ion exchange properties and physical bonding characteristics, and controlling parameters such as viscosity, concentration, and curing properties to optimize the fluid's ability to resist freshwater-induced swelling while maintaining effective stabilization.
2Productivity
If wellbore drilling and stimulation operations are conducted, then methane extraction is enabled, but formation laminae erosion occurs due to freshwater contact
Solution Approach 1:
The patent applies the treatment fluid to stabilize formation laminae before freshwater contact occurs during or after drilling and stimulation operations. By performing this stabilization action in advance, the formation is pre-protected against erosion that would otherwise be caused by subsequent freshwater exposure during wellbore operations, thereby enabling productive operations without the harmful erosion effects.
Solution Approach 2:
The patent converts the potentially harmful effect of freshwater contact into a beneficial outcome by using the freshwater itself as part of the treatment fluid system. The treatment fluid is designed to work with or control the freshwater interaction, transforming the erosive potential of freshwater into a controlled process that stabilizes the formation while allowing necessary wellbore operations to proceed.
3Reliability
If eroded material accumulates in the wellbore, then fracture conductivity is reduced, but frequent workovers are required to maintain production
Solution Approach 1:
The patent applies preliminary stabilization treatment to prevent eroded material from forming and accumulating in the first place. By stabilizing the formation laminae before erosion can occur, the treatment prevents the generation of eroded material that would otherwise accumulate in the wellbore and reduce fracture conductivity, thereby eliminating the need for frequent remedial workovers to maintain production.
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
The solution effectively prevents erosion of formation laminae, reduces the need for frequent workovers, and enhances methane production by maintaining the integrity of the wellbore and fractures.
Implementation Method 1
an aqueous curable resin... penetrating at least a portion of the formation laminae with the aqueous curable resin... curing the aqueous curable resin, thereby stabilizing the formation laminae
Implementation Method 2
stabilizing the laminae may require more than just standard ion exchange by the clay and fines stabilizer, but also physical bonding or cohesion to overcome the expansion caused by the swelling of the laminae when exposed to freshwater
Implementation Method 3
maintaining the treatment fluid in the wellbore at a pressure sufficient to prevent the flow of freshwater from the freshwater reservoir into the wellbore
Implementation Method 4
Laminae containing excessive clay is particularly susceptible to freshwater contact due its insufficient salinity, allowing more water molecules to occupy the interstitial space between the laminae layers and cause swelling
Implementation Method 5
the aqueous curable resin is emulsified in the aqueous base fluid
Data Source
AI summary
Methods including introducing a treatment fluid into a wellbore in a subterranean formation, wherein the subterranean formation includes a coal seam gas reservoir, a freshwater reservoir, and formation laminae interposed therebetween, and the wellbore penetrating each, and wherein the treatment fluid comprises an aqueous base fluid and an aqueous curable resin; penetrating at least a portion of the formation laminae with the aqueous curable resin while maintaining the treatment fluid in the wellbore at a pressure sufficient to prevent the flow of freshwater from the freshwater reservoir into the wellbore; curing the aqueous curable resin, thereby stabilizing the formation laminae; creating permeability pathways in the coal seam gas reservoir itself; removing the treatment fluid from the wellbore; recovering gas from the coal seam gas reservoir.