(1) The cement slurry configured with petroleum-grade PAC can improve the fluidity of the cementing fluid, make it have a suitable initial viscosity, and a lower fluid loss, while protecting the well wall and preventing the fluid from entering the pores and cracks.
(2) Packing fluid configured with polyanionic cellulose can adjust the fluidity, thixotropy and ability of the suspended solid phase of the liquid. Because the product has better salt resistance (especially monovalent metal ions), the product has obvious effect on cleaning brine type packer fluid.
(3) The workover fluid prepared with polyanionic cellulose (PAC) is low solid, which will not block the permeability of the production layer due to solids, and will not damage the production layer; and has a low water loss, so that the amount of water is reduced, and the incoming water will be blocked by the emulsion and form a water town phenomenon. The workover fluid formulated with PAC provides advantages that other workover fluids do not have. Protect the production layer from permanent damage; have the ability to clean the wellbore, and reduce the workload of maintaining the wellbore; have the ability to resist the infiltration of water and sediment, and rarely foam; can be stored or transferred from well to well, lower cost than ordinary mud workover fluid.