An Innovative High-Strength Double-Network Hydrogel for Use as a Drilling Fluid Plugging Agent

Area of Science:

• Petroleum Engineering
• Materials Science
• Polymer Chemistry

Background:

• Wellbore leakage poses significant challenges in the petroleum industry, increasing costs and hindering drilling operations.
• Traditional plugging materials exhibit limitations such as low mechanical strength, poor adaptability to permeable strata, and inadequate resistance to temperature and salinity.
• Effective plugging agents are crucial for enhancing drilling efficiency and reducing operational expenses.

Purpose of the Study:

• To synthesize and evaluate a novel polyacrylic acid-polyacrylamide (PAA/PAM) double-network hydrogel as a plugging agent for wellbore leakage.
• To comprehensively assess the mechanical properties, water absorption, expansion capabilities, temperature resistance, and salt resistance of the synthesized hydrogel.
• To determine the plugging effectiveness of the PAA/PAM hydrogel under simulated downhole conditions.

Main Methods:

• Aqueous solution polymerization was employed to synthesize the PAA/PAM double-network hydrogel.
• Mechanical strength was tested up to 90% strain, and water absorption/expansion was measured over time.
• Temperature and salt resistance were evaluated, alongside plugging effectiveness in simulated high-temperature and high-pressure wellbore leakage tests.

Main Results:

• The synthesized PAA/PAM hydrogel exhibited remarkable mechanical strength, withstanding up to approximately 3.5 MPa at 90% strain.
• Exceptional water absorption and expansion were observed, reaching 6 times expansion in 30 minutes and 8 times after 2 hours.
• The hydrogel demonstrated good temperature and salt resistance, maintaining strength grade E, and effectively reduced drilling fluid leakage to below 5 mL/min at 130 °C and 6 MPa.

Conclusions:

• The novel PAA/PAM double-network hydrogel possesses superior mechanical properties, significant water absorption and expansion capabilities, and excellent high-temperature and salt resistance.
• These characteristics make the synthesized hydrogel a highly promising alternative to traditional plugging materials for addressing wellbore leakage in petroleum drilling.
• The study highlights the potential of this advanced hydrogel for improving drilling efficiency and reducing costs in the oil and gas industry.