A Polymer Plugging Gel for the Fractured Strata and Its Application

Area of Science:

• Petroleum Engineering
• Materials Science

Background:

• Well leakage in fractured strata poses significant drilling challenges due to formation issues and limitations of conventional plugging materials.
• Existing materials often fail due to unsuitable size, low strength, and high costs, leading to repeated plugging attempts.

Purpose of the Study:

• To develop and evaluate a novel polymer plugging gel, XNGJ-3, for effectively mitigating well leakage in fractured geological formations.
• To assess the performance characteristics of XNGJ-3, including its gelling properties, mechanical strength, and deformability.

Main Methods:

• Development of XNGJ-3 using acrylamide, carboxyl, and hydroxyl monomers, designed for controlled gelling at 80°C.
• Laboratory simulation experiments to evaluate the bearing and inverse bearing capacities of XNGJ-3.
• Field verification of XNGJ-3's efficacy in three fractured wells in the Sichuan Basin.

Main Results:

• XNGJ-3 exhibits low viscosity before gelling and controlled gelling time at 80°C, facilitating fracture penetration.
• Simulated experiments demonstrated high bearing capacity (21 MPa) and inverse bearing capacity (20 MPa), exceeding conventional materials by over 100%.
• Field trials confirmed XNGJ-3's high first-time plugging success rate, reduced costs, and shorter work times compared to existing solutions.

Conclusions:

• XNGJ-3 is a highly effective polymer plugging gel for fractured strata, offering enhanced mechanical properties and operational advantages.
• The material's deformability ensures integrity during fracture closure, crucial for long-term wellbore stability.
• XNGJ-3 presents significant engineering value for resolving well leakage issues in challenging fractured formations.