Development and Evaluation Application of a New Type of Composite Bridging Pressure Plugging Agent

For fracture leakage, the formation is easy to leak with low pressure-bearing capacity, based on the force chain theory, the rigid calcium carbonate particles with high strength and high temperature resistance, elastic rubber particles with large deformation rate, shear-resistant acrylic fiber compost, acrylic acid, acrylamide, cationic monomer DDC, etc. as the main polymeric monomers, delayed expansion particles with bentonite, polysaccharide compounds, fibers as support agents and anti-settlement low-density walnut shell particles and ultra-low permeability treatment agent, to develop a composite bridging pressure plugging agent suitable for fracture-based leakage, which has a high pressure-bearing capacity and sealing capacity, easy to form a strong chain network structure, and a relatively high plugging success rate. The performance of its particle size distribution characteristics, pressure resistance, elasticity characteristics, temperature resistance, suspension rate, acid solubility rate, etc. are also evaluated to meet the needs of low pressure-bearing and easy leakage of the target formation. The performance was compared with other field plugging agents, and this plugging agent has wide distribution of D90 value, large elastic deformation rate, adaptability to formation fracture opening, and high compressive strength. The results show that this plugging agent can withstand 1–5 mm cracks > 8 Mpa pressure. Compared with the commonly used bridging plugging materials, it has good sealing advantages. The plugging agent was applied in the field, and two wells were carried out for field testing, and the success rate of secondary plugging reached 100%, which solved the problem of borehole leakage in complex formations and reduced non-productive operation time.