Spread Crosslinker Delayed Viscosity for Downhole Water Control
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Solution Overview
Problem
Current well treatment fluids for hydrocarbon recovery, particularly in fracturing processes, face challenges in efficiently managing viscosity and energy consumption during pumping, and in preventing unwanted water flow into wellbores, which affects the effectiveness and efficiency of hydrocarbon extraction.
Innovation Solution
A crosslinkable fluid comprising a solvent, a crosslinkable component, and a spread crosslinker with chelated polyvalent metal atoms, allowing for delayed crosslinking and increased viscosity upon contact with the subterranean formation, thereby reducing energy consumption and minimizing water flow into the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If crosslinking is delayed to reduce energy consumption during pumping, then viscosity is maintained lower during transport but crosslinking must be triggered effectively at the formation
Solution Approach 1:
The patent introduces pH buffer systems and redox-sensitive groups as intermediary mechanisms that mediate between the crosslinker and polymer. These intermediaries remain dormant during pumping but automatically activate crosslinking when exposed to formation conditions (pH changes or redox environments), ensuring reliable crosslinking trigger without premature viscosity increase during transport.
Solution Approach 2:
The patent employs pH-sensitive and redox-sensitive crosslinking mechanisms where the crosslinking state is controlled by changes in pH or oxidation-reduction potential. By designing crosslinkers that respond to these parameter changes, the system maintains low viscosity during pumping (stable parameters) and triggers crosslinking at the formation (changed parameters), resolving the contradiction between energy efficiency and crosslinking reliability.
2Reliability
If high viscosity fluid is used to reduce fluid leak-off and transfer hydraulic pressure efficiently, then well treatment effectiveness improves but energy consumption during pumping increases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the crosslinker and polymer separately in the treatment fluid, both in inactive or low-reactivity states. The fluid is pumped with lower viscosity to reduce energy consumption, and crosslinking occurs preliminarily planned but not yet executed until the fluid reaches the formation, where environmental triggers activate the crosslinking to achieve the desired high viscosity and treatment effectiveness.
Solution Approach 2:
The patent creates a dynamic viscosity system where the fluid viscosity is not fixed but changes in response to environmental conditions. The fluid starts with low viscosity for efficient pumping, then dynamically increases viscosity when triggered by formation conditions (pH, redox, temperature), allowing the system to adapt its properties to different operational phases and resolve the energy effectiveness contradiction.
3Stability of the object's composition
If crosslinking occurs within the wellbore, then viscosity increases early but friction pressures within tubing increase
Solution Approach 1:
The patent extracts the crosslinking reaction from the pumping process by using triggers that are absent during transport but present at the formation. By taking out the crosslinking trigger (pH change, redox condition) from the wellbore environment and placing it only at the formation, the system prevents crosslinking during pumping (avoiding high friction pressures) while ensuring crosslinking occurs at the target location (achieving viscosity stability where needed).
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 enables efficient pumping with lower friction pressures and effective sealing of subterranean formations, reducing water infiltration and enhancing hydrocarbon recovery by maintaining high viscosity at the rock face rather than within the wellbore, thus improving energy efficiency and extraction outcomes.
Implementation Method 1
the spread crosslinker having a headgroups separated by an intervening spacer that is covalently bound to the headgroups, where headgroups may include a first head group having at least one ring of at least five atoms, where at least two of the atoms in the at least one ring of the first headgroup are chelated polyvalent metal atoms
Implementation Method 2
a crosslinking composition comprising a spread crosslinker... Crosslinking a polymer solution may increase the steady shear viscosity up to two orders of magnitude
Implementation Method 3
Typical polymeric thickening agents for use in such fluids comprise galactomannan gums, such as guar and substituted guars such as hydroxypropyl guar and carboxymethylhydroxypropyl guar (CMHPG)... To increase the viscosity, and, therefore, the proppant carrying ability of the fracturing fluid
Implementation Method 4
the properties of thickened crosslinked fluid are available at the rock face... effective sealing of subterranean formations, reducing water infiltration
Data Source
AI summary
A crosslinker composition including a spread crosslinker for treating a subterranean formation is provided along with methods of sealing a subterranean formation including introducing a crosslinkable fluid, the crosslinkable fluid containing a spread crosslinker and a crosslinkable component, into a subterranean formation.