Development and characterization of a new high-temperature resistant, self-healing and degradable plugging agent for deep shale gas wells

Objective To address the shortcomings faced by conventional plugging materials in the plugging process of deep shale gas well.

Method A new type of plugging agent with self-healing and degradable functions was prepared by crosslinking epoxy resin, succinic anhydride, acetylacetone zinc hydrate, and polyethylene glycol (PEG) using a high-temperature curing method.

Result The plugging agent could withstand temperatures up to 180 ℃, and the mass loss rate after hot rolling at 180 ℃, 16 h was less than 1.6%. Under the condition of 180 ℃, the stress relaxation time could be adjusted within 2 000—6 000 s. After doping with 25 wt% PEG, the plugging agent could achieve 100% complete healing effect within 25 min. Under a high-temperature alkaline environment, it could degrade rapidly. When the NaOH dosage was 1.5 wt%, the plugging agent could be completely degraded within 1 h. The pressure bearing capacity of plugging 5 mm × 4 mm cracks at 180 ℃ could reach 10.0 MPa.

Conclusion The newly developed glass-like polymer plugging agent has good high-temperature resistance, temperature-sensitivity self-healing, and self-degradation properties, which can effectively solve the leakage problem of deep shale gas wells and meet their efficient exploration and development needs.