Experimental Research on Cationic Surfactants in the Drag Reduction of Water Injection Pipeline

To achieve the throughput increase and drag reduction of the water injection pipeline for offshore oil fields, this paper takes the cationic surfactant solution as the research object and explores the feasibility of applying the additive drag reduction technology to the water injection pipelines through the theological test and drag reduction simulation device. The experimental results show that the cetyltrimethylammonium chloride (CTAC) selected initially has excellent thixotropy, and the viscosity recovery rate within 300 seconds can reach more than 97%. In addition, CTAC/NaSal (sodium salicylate) solution has strong oil resistance and salt tolerance. As the oil concentration increases from 0 to 6,000 ppm, the viscosity only decreases by 8.24%; as the salt concentration increases from 0 to 6,000 ppm, the maximum viscosity growth rate is 87.08%. Furthermore, the CTAC/NaSal has good temperature resistance, which enhances with the increase of concentration. The recommended concentration of drag reducer is 400 ppm, and the maximum drag reduction rate, throughput increase rate, pressure drop reduction rate is 74.19, 76.76, and 67.99%, respectively. Therefore, the CTAC/NaSal solution has broad application prospects in the drag reduction of water injection pipelines.