Sepiolite Oil Well Cement Architecture And Nature Study

Grout hydration is a very complicated physical and chemical process since it experiences so many changes in temperature and pressure. After congelation, cement mantle is one kind of dryness stuff with such shortcomings as microscopic bubble, microcrack in nature which strengthens with the increase of strain force and the rate of strain. When intrinsic and extrinsic factor reach to a certain extent, microcrack extends to a larger crack and makes cement mantle separation out of work.The efficient measure to overcome these shortcomings is to improve cement plasticity and enhance the deformablility of cement mantle.Fiber cement is a grout system which adds fiber into constituents to effect and improve dynamic mechanical property of cement mantle, forming a shield in stress field at the top of crack to improve the fracture toughness of stuff. Inorganic asbestos fiber is a sort of plastify stuff since it improves cement fracture toughness and enhances deformability. But the poisonous property of inorganic asbestos fiber restricts its application, so it tends to be replaced by other natural, innocuity product.Sepiolite is a sort of fibrous slicate clay mineral rich of magnesian and one of the minerals with many applications. Its special net fiber structure made sepiolite good plasticity stuff. This thesis studies the effect of sepiolite on each aspect of cement by lots of experiment. It can be found that sepiolite has little effect on the density of grout and compressive strength but can improve the liquidity of grout, decrease the volume of bleeding and filter loss, enhance the stability of grout and shorten the thickening time of grout through workability experiment. On the basis of workability experiment, the plasticity experiment studies the effect of sepiolite on the cementation strength, folding strength, resistance to impact tenacity, which shows that cement stone has little effect on the early strength. It can be found that superfine cement is characterized by small particle size, large specific area, fast hydration velocity and sepiolite has no outstanding effect on the hydration speed of superfine cement through sepiolite—superfine cement experiment. Sepiolite can also improve workability of superfine cement and enhance cementation strength, folding strength, resistance to impact tenacity of superfine cement.Through electron micrograph, sepiolite is found to have net fiber structure shaped by straw bundle. It is special structure that makes sepiolite have special usage. The gathering fiber structure can bondage, absorb solvent; cementation formed by single fiber and cement particle can improve the plasticity of cement mantle, enhance the deformability of cement mantle.