Amino Group Gel-Time Modifiers for Subterranean Conformance Control
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Solution Overview
Problem
The challenge in oilfield operations is the unwanted production of water from subterranean formations, which leads to inefficiencies in oil and gas production due to high water mobility and the bypassing of less permeable zones by aqueous treatment fluids, necessitating effective conformance control treatments to reduce water permeability.
Innovation Solution
A gellable treatment fluid comprising an aqueous base fluid, an acrylamide monomer unit, an organic crosslinking agent, and a gel-time modifier with at least one amino group is introduced into the subterranean formation to form a gel, allowing for reduced gel-time and increased gel strength, even at lower concentrations of crosslinking agents, thereby enhancing the effectiveness of conformance control treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional crosslinking agents are used to form gels in subterranean formations, then gel strength can be achieved, but gel-time becomes uncontrolled and excessively short at higher temperatures, preventing effective placement
Solution Approach 1:
The patent introduces a delay mechanism that prevents premature crosslinking during pumping and placement operations. The crosslinking agent is designed to remain dormant during injection and only activate after the gel system reaches the target zone, allowing complete placement before gelation begins. This resolves the contradiction by separating the placement phase from the gelation phase in time.
Solution Approach 2:
The patent employs temperature-dependent activation where the crosslinking rate is controlled by formation temperature. Below a threshold temperature, crosslinking is suppressed; above it, crosslinking proceeds at a controlled rate. This allows the gel system to be pumped at ambient temperatures without gelling, then form strong gels once deposited in the hotter formation, resolving the gel-time vs. gel strength contradiction.
2Strength
If crosslinking agents are used at higher concentrations to ensure gel strength, then adequate gel formation occurs, but the risk of premature crosslinking during pumping increases
Solution Approach 1:
The delay mechanism ensures that crosslinking is postponed until after placement is complete. This allows the use of sufficient crosslinking agent concentration for strong gel formation without risking premature reaction during pumping, as the chemical reaction is kinetically suppressed until the delay period expires.
Solution Approach 2:
The patent introduces a delay mechanism as an intermediary between the crosslinking agent and the polymer system. This mediator prevents direct interaction and premature crosslinking during pumping, while allowing full crosslinking to occur after placement, thus enabling reliable use of adequate crosslinking agent concentrations.
3Loss of time
If gel-time is extended to allow proper placement, then adequate placement time is achieved, but the treatment becomes less effective at higher temperatures where crosslinking rates are naturally faster
Solution Approach 1:
The patent introduces a temperature threshold parameter that controls crosslinking activation. Below this threshold, crosslinking is suppressed regardless of temperature variations, providing consistent placement time. Above the threshold, crosslinking proceeds at a controlled rate. This resolves the contradiction by making the system's gel-time independent of formation temperature variations during the placement phase.
Solution Approach 2:
The delay mechanism provides a fixed placement time window that is independent of formation temperature. This allows adequate placement time to be achieved consistently across different temperature conditions, as the crosslinking activation is postponed until after placement is complete, regardless of the formation's thermal state.
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 use of the gellable treatment fluid with a gel-time modifier enables effective placement and performance in subterranean operations by reducing gel-time and maintaining suitable gel strength, even at lower concentrations of crosslinking agents, thus addressing the issue of unwanted water production and improving oil and gas recovery.
Implementation Method 1
Gel-time modifiers comprising at least one amino group, any salt, any derivative, or any combination thereof can be used in gellable polymer systems to modify gel-times
Implementation Method 2
The gellable polymer systems can form a gel through crosslinking a water-soluble polymer using a crosslinking agent
Implementation Method 3
conformance control treatments, whereby high permeability zones become fully or partially blocked to fluid flow
Data Source
AI summary
Gellable treatment fluids comprising: an aqueous base fluid; a base polymer comprising an acrylamide monomer unit; an organic crosslinking agent comprising a crosslinkable polymer; and a gel-time modifier. The organic crosslinking agent comprising a crosslinkable selected from the group consisting of polyethyleneimine, polyvinylamine, any derivative thereof, any salt thereof, and any combination thereof. The gel-time modifier comprising at least one amino group, any salt thereof, any derivative thereof, or any combination thereof.