Preparation and Performance Evaluation of Gelled Composite Plugging Agent Suitable for Fractured Formation

Area of Science:

• Drilling Engineering
• Materials Science
• Petroleum Engineering

Background:

• Lost circulation in fractured formations presents a significant challenge in drilling operations.
• Conventional plugging methods often result in unstable sealing layers with inadequate pressure-bearing capacity.

Purpose of the Study:

• To develop an efficient composite plugging agent for fractured formations.
• To investigate the synergistic plugging effects of composite systems.
• To evaluate the performance of the developed plugging agent under various conditions.

Main Methods:

• Laboratory-scale fracture plugging evaluation apparatus.
• Standard comparative experimental methods.
• Formulation optimization of composite plugging agents (calcite particles, elastic gel particles, polypropylene fibers).

Main Results:

• Single components showed limited plugging effectiveness.
• Composite plugging agents significantly enhanced performance.
• The optimal ternary composite (5% calcite, 3% elastic gel, 2% fibers) achieved 13 MPa pressure capacity in 2 mm fractures.
• The composite agent demonstrated high temperature resistance (180 °C) and low fluid loss (50 mL).

Conclusions:

• The developed composite plugging agent offers superior and stable sealing in fractured formations.
• The ternary composite system shows excellent adaptability to varying fracture roughness and compatibility with drilling fluids.
• This composite plugging agent holds significant potential for practical application in oilfield drilling engineering.