The article considers the possibility to apply a gas-volumetric porometer for determining pore volume compressibility coefficient of low-permeability rocks. The proposed method is an alternative to the existing time consuming laboratory research tests. The core used in the experiments was from one of the fields in Western Siberia. The proportion of samples drilled parallel to the bedding planes was 80%. Maximum coverage of lithotypes was provided (from medium-fine-grained sandstone to fine-grained siltstone with different carbonate and clay content). Experimental studies were carried out both with a gradual increasing of confining pressure (ascending branch) and with a gradual decreasing of confining pressure (descending branch). Exponential and linear dependence for porosity and power-law dependence for pore volume were used to approximate the experimental data. It was shown that there is practically no difference between different models. The behavior of some samples was not described with the proposed dependencies. Pore volume compressibility coefficient may be estimated as 10·10-4 MPa-1 when the porosity is over 10 %. Its maximum value was 286·10-4 MPa-1. The obtained values are consistent with the results of other researchers. According to the results of researches it was concluded that the determination of pore volume compressibility coefficient for low-permeability rocks by a gas-volumetric method is an acceptable alternative to traditional methods. But it should be kept in mind that the results obtained when performing such studies should be considered only as an express upper bound, because in the case of low-permeability rocks, the compressibility values determined by other methods will be lower due to the fluid-rock interactions.
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