Filter Cake Degradation Fluid Using Relative Permeability Modifiers
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Solution Overview
Problem
The removal of filter cake deposited by drilling and servicing fluids in well bores often results in uncontrolled fluid losses and damage to formations, as existing methods like acidic solutions can corrode equipment and be incompatible with permeable formations, while water-soluble bridging agents require long dissolution times due to polymeric shielding.
Innovation Solution
A filter cake degradation fluid containing a water-soluble relative permeability modifier is used to degrade the filter cake, which prevents fluid loss by retaining the modifier in the well bore and allowing it to break down the cake along the entire completion interval, utilizing a solvent and additives like acids or enzymes to enhance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strongly acidic solution is used to degrade filter cake, then filter cake removal is effective, but metallic surfaces and completion equipment are corroded and formation is damaged
Solution Approach 1:
The patent changes the chemical parameters of the degradation fluid from strongly acidic to mildly acidic or neutral pH conditions. The fluid composition is modified to include biodegradable polymers and enzymes that can effectively degrade filter cake at lower acidity levels, thereby eliminating corrosion of metallic surfaces and damage to permeable formations while maintaining effective filter cake removal
Solution Approach 2:
The patent employs biodegradable polymers and enzymes that break down naturally after performing their function. These biodegradable components replace the need for harsh, persistent acidic solutions, allowing effective filter cake degradation followed by natural breakdown of the treatment fluid itself, avoiding long-term formation damage
2Ease of manufacture
If water soluble particulate solid bridging agent is used in filter cake, then filter cake can be dissolved, but dissolution requires relatively long period of time due to polymeric shielding
Solution Approach 1:
The patent introduces enzymes as intermediary agents that specifically target and break down the polymeric suspending agents in the filter cake. These enzymes act as catalysts that accelerate the degradation of the polymer matrix, releasing the water-soluble bridging particles and enabling their rapid dissolution without requiring extended contact times
Solution Approach 2:
The patent employs oxidative enzymes and chemical agents that accelerate the breakdown of polymeric materials in the filter cake. These oxidizing agents rapidly degrade the polymer structure, exposing and releasing the bridging particles for quick dissolution, thereby dramatically reducing the time required for complete filter cake removal
3Productivity
If filter cake removal is performed in open hole completions, then filter cake can be cleaned, but uncontrolled fluid losses occur into the formation leading to formation damage
Solution Approach 1:
The patent employs a self-regulating fluid system where the treatment fluid automatically controls its own flow and retention. The fluid contains viscosity modifiers and fluid loss control agents that cause it to naturally retain in the wellbore and selectively interact with the filter cake, degrading it in place without requiring high flow rates that would cause uncontrolled fluid loss into the formation
Solution Approach 2:
The patent applies preliminary fluid loss control measures by incorporating fluid loss control agents in the treatment fluid before injection. This preliminary action prevents uncontrolled fluid loss into the formation from occurring in the first place, allowing the filter cake degradation to proceed without the harmful side effect of formation damage from fluid intrusion
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 method effectively removes filter cake while minimizing fluid loss and preventing formation damage, maintaining permeability for hydrocarbon production and injection without the need for subsequent treatments, and can be used in both cased and open hole completions.
Implementation Method 1
a relative permeability modifier that prevents fluid loss and retains the filter cake degradation fluid in the well bore
Implementation Method 2
contacting at least a portion of the filter cake with a filter cake degradation fluid... allowing the filter cake to degrade
Implementation Method 3
utilizing a solvent and additives like acids or enzymes to enhance degradation
Data Source
AI summary
A method of treating a subterranean formation including providing a well bore that includes a filter cake on at least a portion of the well bore and contacting at least a portion of the filter cake with a filter cake degradation fluid comprising a relative permeability modifier. The method also includes allowing the relative permeability modifier to retain at least a portion of the filter cake degradation fluid in the well bore for a time sufficient to contact the filtercake and allowing the filter cake to degrade.