# Synthesis and Performance Evaluation of Polyamine Boron Crosslinker for Gel Fracturing Fluid

## TL;DR

This paper introduces a new crosslinker for fracturing fluid that improves performance and reduces damage in low-permeability oil and gas reservoirs.

## Contribution

The novel polyamine boron crosslinker (PBC) offers dynamic reversible crosslinking and low-damage performance at low concentrations.

## Key findings

- PBC crosslinker achieved stable viscosity of ~100 mPa·s under 60 °C and 100 s−1 shear.
- The crosslinker demonstrated a low wall forming filtration coefficient and good suspended sand capacity.
- Optimal synthesis conditions were determined with a model prediction error of 0.7%.

## Abstract

The fracturing development of low-permeability and ultra-low-permeability oil and gas reservoirs urgently requires a fracturing fluid that combines high performance and low damage. To overcome this challenge, this study synthesized a novel polyamine boron crosslinker (PBC) suitable for 0.2% guar gum. The molecular structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (1H NMR). Meanwhile, this study introduced the response surface methodology and established a second-order regression model to determine the optimal synthesis conditions (polyetheramine 10.8 g, n-butanol 7.4 g, and ethylene glycol 20.7 g) with a model prediction error of only 0.7%. The results indicated that PBC exhibited excellent performance in 0.2% guar gum. The viscosity of crosslinked gel fracturing fluid remained stable at approximately 100 mPa·s under 60 °C and 100 s−1 shear. The wall forming filtration coefficient was 2.30 × 10−4 m/s1/2, and the initial filtration was 1.30 × 10−3 m3/m2. The static settling rate was 2.4 cm·min−1, demonstrating good suspended sand capacity. Furthermore, the synergistic interaction between borate ester bond and polyetheramine in the PBC conferred dynamic reversible crosslinking and uniform network formation. This enabled high-strength, low-damage crosslinking effects at low concentrations. This study provides an efficient crosslinker solution for 0.2% guar gum, holding both theoretical and engineering significance for advancing the low-cost development of fracturing fluid.