Air-foamed calcium aluminate phosphate cement for geothermal wells

摘要: Abstract Air-foamed low-density calcium aluminate phosphate (CaP) cement slurry was prepared by mixing it with chemical foaming reagent at room temperature without any pressure, followed autoclaving 200 °C. When the porosity, compressive strength, and water permeability of autoclaved CaP foam made from a 1.22 g/cc density compared those N2 gas-foamed Class G similar under high pressure hydrothermal 288 °C, revealed some advanced properties, such as higher strength lower porosity. These properties were due to hybrid formation three crystalline reaction products; hydroxyapatite, boehmite, hydrogarnet phases. However, one shortcoming an increase in because undesirable continuous porous structure caused coalesced air bubble cells, suggesting that appropriate lesser amount be used create conformation which fine discrete air-bubble cells are uniformly dispersed throughout slurry. For non-foamed cement, major factors contributed protecting carbon steel against corrosion: (1) good adherence steel, reflecting extent coverage layer over steel’s surfaces; (2) retardation cathodic corrosion reactions; and, (3) minimum conductivity corrosive ionic electrolytes. adding excessive did not offer effective protection cement.