Charged Polymeric Gelling Agent for Proppant Suspension
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Solution Overview
Problem
High salinity, low viscosity subterranean treatment fluids struggle to effectively suspend proppant particulates due to reduced viscosity and premature settling, which can lead to fracture closure and reduced production potential in hydraulic fracturing operations, especially when using seawater or produced water as the base fluid.
Innovation Solution
A method and composition using a high salt concentration base fluid combined with a charged polymeric gelling agent, such as derivatized guar gum or cellulose derivatives, and optional crosslinking agents, which maintain low bulk viscosity (30-150 cP) while effectively suspending proppant particulates, even in high salt environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high salt concentration base fluid is used, then fluid availability and environmental compatibility improve, but proppant suspension capability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the gelling agent to be compatible with high salt concentrations. Specifically, it uses crosslinking systems that function effectively in saline environments, altering the chemical composition parameters to resolve the contradiction between using salt water (improved availability) and maintaining proppant suspension (stability requirement).
Solution Approach 2:
The patent creates a composite treatment fluid system combining high salt concentration base fluid with specific gelling agents and crosslinking agents. This composite approach allows the fluid to simultaneously achieve good proppant suspension and compatibility with salt water sources, resolving the contradiction between fluid availability and suspension capability.
2Stability of the object's composition
If gelling agents and crosslinking agents are used to viscosify fluid, then proppant suspension capability improves, but salt concentration compatibility deteriorates
Solution Approach 1:
The patent selects gelling agents and crosslinking agents with specific chemical parameters that enable them to maintain effectiveness in high salt environments. The crosslinking system is specifically chosen to resist salting out and syneresis, changing the chemical parameters to achieve both proppant suspension and salt tolerance.
Solution Approach 2:
The patent employs a crosslinking system that provides sufficient viscosity and suspension capability for the duration of the fracturing operation, even in high salt conditions. The system is designed to be effective for the required time period without requiring long-term stability, allowing the use of materials optimized for immediate performance in saline environments.
3Ease of operation
If fluid viscosity is reduced, then fluid pumpability improves, but proppant suspension capability deteriorates
Solution Approach 1:
The patent creates a dynamic viscosity system where the fluid exhibits appropriate viscosity during pumping and proppant suspension, then breaks down after injection. The crosslinking system provides temporary viscosity enhancement for suspension, then degrades to improve pumpability during fluid return, resolving the contradiction between suspension stability and pumpability.
Solution Approach 2:
The patent applies crosslinking agents to establish viscosity and proppant suspension capability before the fracturing operation begins. This preliminary action ensures proppant remains suspended during injection and placement, while the system is designed to break down afterward to restore pumpability for fluid return.
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 achieves prolonged proppant suspension with minimal settling, maintaining fracture conductivity and fluid pumpability, even in high salt concentration conditions, outperforming fresh water-based fluids in proppant suspension efficacy.
Implementation Method 1
a charged polymeric gelling agent capable of suspending proppant while exhibiting low viscosity
Implementation Method 2
charged polymeric gelling agent... capable of suspending proppant
Implementation Method 3
proppant suspension... maintaining fracture conductivity... outperforming fresh water-based fluids in proppant suspension efficacy
Data Source
AI summary
Introducing a treatment fluid comprising proppant particulates into a subterranean formation, the treatment fluid comprising a high salt concentration base fluid, a charged polymeric gelling agent, and proppant particulates suspended therein, wherein the high salt concentration base fluid comprises a concentration of salt in the range of from about 0.5% to saturation, and wherein the treatment fluid has a bulk viscosity of from about 30 cP to about 150 cP at a shear rate of about 40 sec−1.