Borate Crosslinker for Hydraulic Fracturing Fluids
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Solution Overview
Problem
Hydraulic fracturing processes face challenges in efficiently delivering proppants due to high viscosity carrier fluids, which increase friction pressure and limit fracture width and length, while existing crosslinking agents lack flexibility in controlling the crosslinking rate to match the timing of pumping and delivery processes.
Innovation Solution
A crosslinking composition comprising a balance of hydroboracite and borax, optimized with additives like canola oil, xanthan, and glycerol, allows for customizable crosslinking rates, maintaining lower viscosity during pumping to reduce friction and achieving higher viscosity upon delivery, thereby enhancing proppant delivery and fracture stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher viscosity carrier fluids are used to carry proppants more effectively, then proppant delivery effectiveness is enhanced, but friction pressure within pumps increases
Solution Approach 1:
The patent applies dynamic viscosity control by using crosslinking agents that adjust the fluid's viscosity over time. The carrier fluid starts with lower viscosity for easy pumping, then progressively increases viscosity through crosslinking reactions during transport, optimizing both pumpability and proppant carrying capacity at different stages of the process.
Solution Approach 2:
The crosslinking agents are pre-added to the carrier fluid before pumping begins, initiating a controlled viscosity increase that progresses during transport. This preliminary action allows the fluid to automatically adapt its viscosity characteristics to match the changing requirements from pumping to proppant delivery.
2Length of stationary object
If higher viscosity fluids are used to carry higher concentrations of proppant, then fracture width is enabled to increase, but friction pressure in the system increases
Solution Approach 1:
The fluid viscosity dynamically evolves from a pumpable state to a high-viscosity gel state during transport. This time-dependent viscosity change allows the system to achieve high fracture width capability at the destination while maintaining acceptable pumping pressures during transport.
3Adaptability or versatility
If existing crosslinking agents are used, then crosslinking can occur, but flexibility in controlling the crosslinking rate to match pumping and delivery timing is limited
Solution Approach 1:
The patent introduces multiple crosslinking agents with different reaction rates and mechanisms. By selecting and combining agents with specific kinetic properties, the system can precisely control the timing and rate of viscosity development to match various pumping and delivery schedules, eliminating timing mismatches.
Solution Approach 2:
The composition uses composite crosslinking systems combining multiple agents (e.g., borax, boric acid, zinc chloride) that work synergistically. This composite approach provides broader control over crosslinking kinetics, allowing customization of the viscosity development profile to match specific operational requirements.
4Speed
If crosslinking occurs too quickly after mixing, then high viscosity is achieved rapidly, but the fluid may not be deliverable to fractures in time
Solution Approach 1:
The crosslinking process is designed to be dynamic and controllable, progressing at a rate that can be matched to the pumping and delivery schedule. The fluid transitions from a low-viscosity pumpable state to a high-viscosity deliverable state over a controlled time period, ensuring availability at the fracture destination.
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 proppant delivery with reduced friction pressure and increased fracture width and length, while allowing for tailored crosslinking timing to match hydraulic fracturing operations, improving the overall effectiveness of the fracturing process.
Implementation Method 1
customizable crosslinking rates... as the balance between hydroboracite and borax favors hydroboracite, the rate at which the composition crosslinks guar will decrease. Likewise, as the balance favors borax, the rate at which the composition crosslinks guar or HPG will increase.
Implementation Method 2
Crosslinking hydrated guar suspensions, or suspensions of various guar derivatives, can create a gel fluid with relatively high viscosity.
Implementation Method 3
a thickening or stabilizing agent such as xanthan or a similar rheology modifier, and a polyol such as glycerol
Data Source
AI summary
The present disclosure relates to a crosslinking composition for use in crosslinking an aqueous suspension of guar, for use as a well treatment fluid and/or proppant carrier fluid for natural gas extraction. The present crosslinking composition is an aqueous suspension of hydroboracite. The composition may also comprise varying amounts of borax, canola oil, xanthan, glycerol, and/or NaOH. The composition may be selected to effect a desired delay in the crosslinking reaction in order to customize the viscosity and reaction time to the method of use, thereby maximizing proppant delivery while minimizing pump pressure.