Development of cost-effective repair system for locally damaged long-distance oil pipelines

The traditional maintenance method for locally damaged long-distance oil pipeline involves hot work. Tedious technological processes are required to prevent the explosion of oil and gas due to the existence of combustible oil and gas in the pipeline. This study presents and verifies an economical and efficient replacement method for partially damaged oil pipelines. The core of the new method is to inject temporary plugging material to isolate the locally damaged pipeline and then carry out hot work. The temporary plugging material is composed of hydrogel and composite clay. The main function of hydrogel is to push away the residual oil to form an isolated oil and gas area. When the plugging length was 3 m, the hydrogel can resist the maximum pipeline pressure of 29.46 kPa. The composite clay increased the plugging capacity, thereby achieving plugging with pressure. When the plugging length was 2 m, the maximum resistance pressure of the composite clay was 0.49 MPa. The use ratio of the two materials can be flexibly adjusted in accordance with the actual plugging pressure. When the pipeline pressure was greater than the maximum plugging pressure, the plugging area was damaged, and the pipeline resumed transportation. In addition, hydrogels possess excellent heat absorption ability, which can reduce heat transfer during hot work to ensure safety. The hydrogels can be collected from the filtration station after the operation completion and can be recycled after simple treatment to reduce construction costs. The new replacement method of locally damaged oil pipeline has evident advantages compared with the traditional method.