Research of Nanosilica Particles Grafted with Functional Polymer Used as Fluid Loss Additive for Cementing under Ultra-High Temperature

Abstract

On account of that the domestic polymer fluid loss additive exists some severe problems, such as, inferior thermal resistance, poor salt tolerance, strong shear-and thermal thinning behavior, a novel polymer/silica nanocomposite PADMO-V@NS is used as ultra-high temperature fluid loss control additive for cementing. In the present study PADMO-V@NS was prepared through an in situ free radical copolymerization of 2-acrylamico-2-methylpropane sulfonic acid (AMPS), N,N-dimethylacryl amide (DMAM), maleic anhydride (MA), octadecyl dimethylallyl ammonium chloride (ODAAC) and triethoxyvinylsilane (VTS) modified nanosilica. The linear hydrophobic associated copolymer was regarded as the shell and the modified nanosilica as the core. The microstructure, compositions and thermal resistance of PADMO-V@NS were investigated through FTIR and TGA techniques. The results showed that the copolymer modified with nanosilica particles possessed more excellent thermal stability than that of PADMO, and the most rapid decomposing temperature of PADMO-V@NS was highly up to 396.9°C. The application performance of PADMO-V@NS in cement slurry exhibited that it had excellent fluid loss control capacity, good high temperature resistance, strong salt tolerance and mild shear-/ thermal thinning performance, and could be used in 220°C and saturated brine circumstances. Moreover, comparing to PADMO, the compressive strength of set cement containing the copolymer increased over 20 % at 80°C, atmosphere pressure and curing time of 1 day due to the reaction of residual silanol groups with Ca (OH)2. The laboratory research results indicated that the multi-functional fluid loss additive composed of hydrophobic associated polymer/silica nanocomposite had bestowed on the cement slurry systems good comprehensive properties, and may have extensive applications in deep & ultra-deep oil/gas wells cementing.

Synthesis of a hydrophobic associating polymer and its application in plugging spacer fluid

“…According to literature reports, the longest ultraviolet absorption wavelength of pyrene is 272 nm. [21][22][23] When the environmental polarity is weaker, the number of hydrophobic micro-regions and the ultraviolet absorption peak redshi of pyrene increases.…”

Research on graphene oxide modified polymer as multifunctional filtration reducer for oil-well cementing

“…To improve the effectiveness of AMPS polymer filtration reducers, several traditional approaches can be implemented. One is copolymerized by temperature-resistant and salt-tolerant monomers with optimal molecular structure and weight [6][7][8] , another is introduced functional inorganic substances or organic molecules to graft and modify the filtration reducers [9,10] . And formulating filtration reducers and other additives is for the synergism can also be available [11] .…”

“…The research results showed that the diblock copolymer with lower molecular weight than the conventional polymer can control fluid loss without negative impacts. Xia et al [9] synthesized a new type of hydrophobically associative polymer/nano-silica composite material with micro-crosslinked structure to improve the ultra-high temperature performance of traditional filtration reducers. The composite demonstrates exceptional thermal stability and possesses the ability to strengthen cement.…”