Biodegradable Activators Gel Silica Sol for Water Blocking
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Solution Overview
Problem
Current methods for controlling water production in oil and gas wells are inadequate, particularly at high temperatures, as they often involve unstable polymers that degrade, posing environmental risks and requiring frequent re-treatment, which increases costs and can harm the environment.
Innovation Solution
A conformance system using a water-based treatment fluid comprising an aqueous silica sol and a biodegradable chemical activator, such as phytic acid or methylglycinediacetic acid, to gel the silica sol in-situ, reducing permeability in treatment zones and effectively blocking water production without damaging the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymers are used to control water production, then water blocking is achieved, but the polymers degrade at high temperatures causing environmental harm and requiring frequent re-treatment
Solution Approach 1:
The patent changes the fundamental parameter of material composition from conventional degradable polymers to silica-based materials that maintain stability at high temperatures. The silica sol system with controlled gelation allows the material to remain stable under high temperature conditions (up to 300°F) without degrading, thereby eliminating environmental harm while maintaining reliable water blocking performance.
Solution Approach 2:
The patent employs a composite system combining silica sol with specific chemical activators (such as borax, boric acid, or silane coupling agents) to create a treatment material that exhibits both stability and effectiveness. This composite approach allows the silica-based material to achieve the desired gel structure for water blocking while resisting thermal degradation that plagues conventional polymers.
2Duration of action of stationary object
If conventional polymers are used for water blocking, then initial water control is achieved, but frequent re-treatment is required increasing costs
Solution Approach 1:
The patent fundamentally changes the material parameter from degradable polymer to thermally stable silica-based material, which maintains its structural integrity and water blocking capability at high temperatures over extended periods. This parameter change eliminates the degradation-retreatment cycle, extending the duration of action from months to potentially the lifetime of the well, thereby improving operational efficiency.
3Reliability
If silica sol is used to reduce permeability, then stable high-temperature performance is achieved, but the silica sol must remain stable during injection and only gel in-situ
Solution Approach 1:
The patent applies preliminary action by pre-formulating the silica sol with specific concentrations and preparing the chemical activators separately before injection. The system is designed so that the silica sol remains stable during injection (preliminary state) and only undergoes gelation after injection when the activator is introduced or conditions change in-situ. This preliminary preparation simplifies the overall system by separating the stability requirement during injection from the gelation requirement for water blocking.
Solution Approach 2:
The patent uses chemical activators (such as borax, boric acid, or silane coupling agents) as intermediaries that trigger the gelation of silica sol under specific conditions. These intermediaries allow the silica sol to remain stable during injection and transport, then initiate controlled gelation in-situ when they interact with the silica sol, providing a simple mechanism to manage the transition from liquid to gel state without complex control systems.
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 system provides a stable and environmentally friendly solution that reduces permeability, effectively controlling water production and promoting hydrocarbon production, with the silica sol remaining stable at temperatures up to 300°F, thus extending the economic life of wells and reducing operating costs.
Implementation Method 1
a water-soluble chemical activator for gelling the silica sol, wherein the chemical activator is selected from the group consisting of: (a) phytic acid, an alkali metal salt or ammonium salt thereof
Implementation Method 2
shutting in treatment zone for at least a sufficient time to allow the treatment fluid to in-situ form a solid gel at a design temperature for the method
Data Source
AI summary
A method of treating a treatment zone in a well to reduce the permeability of the treatment zone including the steps of: introducing into the treatment zone a water-based treatment fluid comprising: an aqueous silica sol; and a water-soluble chemical activator for gelling the silica sol, wherein the chemical activator is selected from the group consisting of: phytic acid, methylglycinediacetic acid, a water-soluble polyepoxysuccinic acid, salicylic acid, ascorbic acid, tannic acid, and an alkali metal salt or ammonium salt of any of the foregoing; and shutting in treatment zone for at least a sufficient time to allow the treatment fluid to in-situ form a solid gel at a design temperature for the method. Alternatively, a first treatment fluid including the aqueous silica sol and a second treatment fluid including the chemical activator can be introduced into the treatment zone separately, in any order.