The Synthesis and Performance of a Novel Lignin Modified Salt-Resistant Branched High-Performance Water Reducer

A lignin modified salt-resistant branched high-performance water reducer was prepared via free radical polymerization. The water-reducing agent was identified through its NMR spectrum, elemental analysis, Fourier transform infrared analysis, thermal gravimetric analysis, and scanning electron microscopy. The experiment conducted on cement paste demonstrates that the water-reducing efficiency can reach a maximum of 44%. Additionally, the significant spatial steric hindrance of the application enhances the dispersal capability of the water-reducing agent, resulting in effective water reduction and reduced viscosity. In addition, its compressive strength is the highest after 3-day curing and 3-, 7-, 28-day standard curing, and it has the best overall performance both in water and saline water prepared systems. The application in oil cement slurry shows that it exhibits a good dispersibility in fresh water, saline water, and substitute ocean water. In the Halfaya and Missan Oilfields of Iraq, BHPWR was used in a slurry with a density of 2.28 g/cm³ for casing the salt paste layer of five wells. The cementing results exceeded expectations with 100% qualified including over 85% excellent.