Enzyme Breaker Activation via pH Reduction
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Solution Overview
Problem
Conventional enzyme breakers used in oilfield applications are limited by their sensitivity to temperature, pH, and salinity, leading to reduced activity and stability, especially at high temperatures above 93°C, which hampers effective removal of polymer-based filtercakes in subterranean formations.
Innovation Solution
A method involving a well treatment fluid with an enzyme and a breaker additive that initially has a pH of 11.5, where the breaker additive reduces the pH by at least 1.5 to activate the enzyme, allowing for the degradation of crosslinkable components and polymer chains, even at elevated temperatures, using encapsulated acids or esters that slowly release acid to control the pH reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional enzyme breakers are used in oilfield applications, then they can break down polymer-based filtercakes, but their activity and stability are reduced at high temperatures above 93°C
Solution Approach 1:
The patent modifies the enzyme's operating parameters by adjusting pH conditions and using pH-modifying agents to optimize enzyme activity at elevated temperatures. The system changes the chemical environment (pH, ionic strength) to maintain enzyme stability and activity in high-temperature subterranean formations, directly addressing the temperature-related reliability issue.
2Productivity
If the pH of the well treatment fluid is reduced to activate the enzyme, then the enzyme activity increases, but the initial high pH of 11.5 must be overcome
Solution Approach 1:
The patent incorporates pH-modifying agents and encapsulated acids into the well treatment fluid formulation in advance, before the fluid is deployed. These agents are pre-positioned to gradually lower the pH and activate the enzyme breaker, ensuring that the pH transition is controlled and timed appropriately for optimal enzyme performance.
Solution Approach 2:
The patent uses pH-modifying agents and encapsulated acids as intermediary substances that mediate between the initial high pH environment and the enzyme's optimal pH range. These intermediaries gradually adjust the pH conditions, enabling the enzyme to become activated without subjecting it to abrupt pH changes that could cause instability.
3Use of energy by moving object
If polymeric thickening agents are used in fracturing fluids, then the fluid viscosity increases for effective proppant transport, but formation damage occurs due to filtercake deposition
Solution Approach 1:
The patent uses enzyme breakers to selectively degrade and remove the polymeric thickening agents from the filtercake structure. The enzymes extract and break down the polymer chains that are trapped in the formation, removing the harmful filtercake deposition while preserving the beneficial proppant transport function that occurred during the fracturing operation.
Solution Approach 2:
The patent enables the discarding of the polymeric thickening agents after they have fulfilled their transport function. The enzyme breakers facilitate the degradation and removal of these polymers from the formation, allowing the system to recover from the temporary formation damage by eliminating the filtercake that caused the harm.
4Productivity
If breaker additives are used to reduce pH and activate enzymes, then polymer degradation is accelerated, but the complexity of the fluid formulation increases
Solution Approach 1:
The patent employs pH-modifying agents and encapsulated acids that automatically adjust the pH conditions and activate the enzyme breaker without requiring external intervention or complex control systems. The formulation is designed to self-regulate the pH transition and enzyme activation process, simplifying the overall system despite the multiple components involved.
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 approach enhances the activity and stability of enzymes at higher temperatures, enabling effective breakdown of polymer-based filtercakes and improving hydrocarbon production by maintaining enzyme activity and reducing viscosity of viscosified fluids, thus optimizing well performance.
Implementation Method 1
the breaker additive reduces the pH of the well treatment fluid by at least 1.5 to increase the activity of enzyme and accelerate hydrolysis of a crosslinkable component
Implementation Method 2
accelerate hydrolysis of a crosslinkable component
Implementation Method 3
using encapsulated acids or esters that slowly release acid to control the pH reduction
Implementation Method 4
using encapsulated acids or esters that slowly release acid
Implementation Method 5
enhances the activity and stability of enzymes at higher temperatures, enabling effective breakdown of polymer-based filtercakes
Implementation Method 6
degradation of crosslinkable components and polymer chains
Data Source
AI summary
A method of treating a subterranean formation, the method including placing a well treatment fluid comprised of at least an enzyme and a breaker additive in the subterranean formation. Initially, the pH of the well treatment fluid is about 11.5. The breaker additive reduces the pH of the well treatment fluid by at least 1.5 to increase the activity of enzyme and accelerate hydrolysis of a crosslinkable component.