Evaluation of permeability grouting stone, formed from the lightweight cement

Construction volume under abnormally low reservoir pressures conditions and drilling of mud losses is the reason for the necessity of using the lightweight cement. The article is devoted to the vapor permeability of cement stone.
Materials and methods
Cement samples were tested according to GOST 25898-83. The water vapor permeability was determined, using the dried sample.
Results
The results of the research confirmed the use of hollow glass microspheres (HGM) and dressed hollow glass microspheres (DHGM) as a part of the lightweight cement slurry, from 2.5 to 7.5%; it reduces the water vapor permeability of the stone, and thus, increases the sealness of the well.
Сonclusions
It is obvious, that the impedance factor of lightweight cement slurry with 5% of HGM or DHGM is up to the standards of waterproofings. Water vapor permeability resistance for all other compositions, described in the article, is considerably higher in comparison with the stone, formed from 100% oil-well portland cement. This is due to gas and water resistance of hollow glass microspheres and the imporosity of lightweight grouting stone with hollow glass microspheres. Cement sheath integrity can be indirectly estimated from vapor permeabilty. Currently, authors of the article developed technology (technological regulations) and regulations (specifications), regulating mixing of mortar and mud application of lightweight cement slurries with HGM and DHGM in the Tomsk region.