Synthesis of a tough montmorillonite/hydrogel composites for hot work of long-distance oil pipelines

Hot work on oil pipelines is a dangerous but essential operation. Traditional process has a large amount of energy waste and inert gas consumption during the operation. This study prepared a tough composite hydrogel that can temporarily block local oil pipelines and then carry out hot work. As a filling material, montmorillonite (MMT) can effectively improve the compressive strength of hydrogels. The composite hydrogel can push the residual oil to both ends of the pipeline to form a safe isolated oil and gas area. The product with a plugging length of 4.5 m withstood the pipeline pressure of 0.67 MPa. In temporary plugging, the plugged pipeline changed to the dredging state when the pipeline pressure exceeded the maximum plugging pressure, simplifying the complex operation process. The flame resistance performance indicated that the composite hydrogel absorbed the heat generated by hot work and ensured the safety of the operation. The prepared plugging material provided obvious advantages such as reducing energy waste and saving time and cost when applied to hot work of oil pipelines.