Delayed Viscosity Well Treatment Fluids
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Solution Overview
Problem
Existing well treatment fluids with low pH crosslinking, such as those using carboxymethyl cellulose (CMC) or carboxymethylhydroxyethyl cellulose (CMHEC), experience rapid viscosity development, leading to pipe friction pressure and mechanical shearing during pumping, which is undesirable.
Innovation Solution
A well treatment method involving a polymer, a crosslinker, and an acidifying substance is used to control pH decrease, delaying viscosity increase by combining these ingredients in a base fluid, where the acidifying substance, such as fumaric acid, is configured to slow down pH reduction, thereby reducing pipe friction and mechanical shearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low pH crosslinking is used with CMC or CMHEC, then viscosity development is rapid, but pipe friction pressure and mechanical shearing increase during pumping
Solution Approach 1:
An acidifying substance is introduced as an intermediary component to control and moderate the pH decrease during viscosity development. This mediator allows the crosslinking process to proceed while preventing the rapid pH drop that causes harmful pipe friction and mechanical shearing, thus resolving the contradiction between productivity and harmful effects.
Solution Approach 2:
The patent modifies the chemical parameters of the system by adding an acidifying substance that controls the pH trajectory during crosslinking. This parameter control ensures that viscosity develops at the desired rate while maintaining pH levels that prevent excessive pipe friction and mechanical shearing, thereby resolving the technical contradiction.
2Loss of time
If crosslinking is performed quickly, then viscosity increases faster, but mechanical shearing of the fluid occurs
Solution Approach 1:
The acidifying substance serves as a mediator that controls the rate of pH decrease during crosslinking. By moderating this chemical change, it enables viscosity development to proceed without causing mechanical shearing, thus resolving the contradiction between time efficiency and avoiding harmful effects.
Solution Approach 2:
By controlling the pH parameter through the addition of an acidifying substance, the patent achieves optimal viscosity development timing while preventing mechanical shearing. This parameter control resolves the contradiction between reducing time loss and avoiding harmful mechanical effects.
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 method effectively delays viscosity development, reducing pipe friction and mechanical shearing during pumping, allowing for safer and more efficient proppant transport and fracture creation in subterranean formations.
Implementation Method 1
A pH decrease is controlled during the development time in the well treatment fluid using the acidifying substance
Implementation Method 2
crosslinking the polymer in the base fluid using the crosslinker. The crosslinking increases viscosity of the well treatment fluid during a development time
Data Source
AI summary
A well treatment method includes forming a well treatment fluid by combining ingredients including a polymer, a crosslinker, an acidifying substance, and a base fluid. Crosslinking increases viscosity of the fluid during a development time. A pH decrease is controlled during the development time using the acidifying substance. The method also includes delaying the development time of the viscosity increase by controlling the pH decrease. A well treatment method includes forming a well treatment fluid by combining ingredients including a hydratable polymer, a crosslinker, an acidifying substance, and a base fluid. The method includes delaying development time of a viscosity increase by controlling a pH decrease without adding further acidifying substance after combining the polymer, crosslinker, acidifying substance, and base fluid. A well treatment fluid formulated with ingredients include a base fluid, a polymer, a crosslinker, and an acidifying substance. The acidifying substance is configured to delay development time.