The New Temperature Oil Well Cement Fluid Loss Additive System

Based on the analysis of the problems for filtrate reducer and its functional mechanism, the thesis research and analysis are made of its influential factors of filtrate reducer controlling water filtering and the substantial causes — forming a mechanism of stopping up filtration channels to the fullest extent. And a new functional mechanism of filtrate reducer is advanced, which can practically serve for guiding a new design and synthesis of filtrate reducer. By the means of chelate and static electricity gravitation of positive and negative ions through coordinate bond, filtrate reducer absorbs firmly on the surface of cement granules, form an absorption layer of high elasticity, viscoelasticity and glutinous macromolecular with some absortion strength, and thickness. Under pressure differences, the viscoelastic material is pressed into the gap of cement granules and glued between cement granules, the filtering passage of filter cake is fully filled and stopped up, the permeability is reduced and the filter cake becomes dense and firm which completely controls water filtering. On the other hand, having greater absorptivity is the key factor for filtrate reducer to control water filtering, for filterability can not be materially controlled by macromolecular being unable to be effectively absorbed on the surface of cement granules. Another factor is that macromolecular being hydrolyzed controls free water and increases the glutinousness of liquid phase. The stronger chelation and absorptivity of filtrate reducer functional group, the thicker absorption coat, the greater proportion on the surface of cement granules, the more favorable to low filtering; the coiled or precipitating macromolecular is also favorable to lower filtering. Thus, the micro-size of the filtering passage of cement slurry is analyzed and a method for calculating the diameter of gradation and molecular weight of filtrate reducer and their range are confirmed.Two new types anti-temperature cement filtrate reducer for oil well are then developed. Under the theoretical guidance of the new mechanism, the molecular structure of new-typed anti-temperature filtrate reducer with which the main bond is the anti-temperature carbon-carbon bond and the main functional group is -SO₃^-,-COO^-,-CONH₂ which has strong ionicity coordination and strong chelation. By the process of monomer-polymerization and polymer sulfonation, two kinds of sulfo acid filtrate reducer are compounded, while the best time for compounding is established and the structure and property are characterized. The...