The majority of natural hydrocarbon oilfields of the Far North are distinguished by frozen rocks and reservoirs with low pressures of hydraulic fracturing in their geological section. It makes complicate well construction. The height of frozen rocks can exceed 500 meters, and their natural temperature varies from 0 to -100 °C. The application of regular grouting mixtures in such geological conditions doesn’t provide a reliable cementing of the casing columns and formation isolation, as long as they harden for a long time, partially freeze, which adversely affects the working properties of cement stone. There is a risk of absorption of the grouting mixture, of the failure of the cement stone on exposure to cyclic freeze-thaw temperature. Therefore the main objective of grouting mixture formulation development for casing cementing in frozen rocks bedding interval – ensuring their freeze-proof properties, fast hardening without shrinkage strain. There is no serial production of the low density grouting mixtures for the low-temperature wells in the national industry. At the present time there are proposed various lightweight additives, among which zeolite is especially important. The paper reviews the problems of well cementing in the conditions of low reservoir pressure and temperature. The authors had developed and researched cement-zeolite grouting mixtures CZTS-1 (density of 1600-1610 kg/m3) and CZTS-2 (density of 1700-1720 kg/m3). The formulation contains binding material PCT I-50 (RF State Standard GOST 1581-96), synthetic zeolite of type NaA and NaX for CZTS-1 and CZTS-2 correspondingly (Technical Specification 2163-003-15285215-2006), stabilizing agent MK-85 under (Technical Specification TU 1714-457-05785388-2011), Natrosol 250EXR (TU 0799-001-99126491-2013), plasticizing agent SP-1 (TU 5870-005-58042865-2005). Process water was used as grouting fluid, 4 % solution of calcium chloride and 4% solution of mineralizing agent “Karnamin” were used for speeding up the setting time. We present the results of laboratory tests of basic working properties of cement-zeolite grouting mixture and stone at the temperatures ((20±2 and 5±2) °C. Optimal values of water-solid ratio for obtaining the grouting mixture of density 1600–1720 kg/m3 is 0.65-0.55.
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