DOI: 10.24412/2076-6785-2021-1-11-16
Abstract
The existing laboratory methods for determining the elastic-strength properties of a weakly consolidated core were adapted, including laboratory pre-saturation of samples with various fluids, as well as while creating pore pressure with gas. The influence of saturating agents on the elasticstrength properties of gas field core samples is studied. Liquids (natural saturation, water, kerosene) and gas (nitrogen) were considered as saturating agents. It was found that, depending on the nature of the saturating agent, changes in the values of the static Young’s modulus, determined during volumetric compression, reach 30 %; the Poisson’s ratio – 10 %. It is shown that when the core sample is saturated with water, the value of the uniaxial compressive strength decreases by 2–4 times, and the Young’s modulus decreases by an average of two times in comparison with the natural saturation of the sample.
Material and methods
Based on the method of preliminary rapid freezing of the rock in liquid nitrogen, core samples are drilled from weakly consolidated rock. Additionally, a tomography is used to monitor the quality and integrity of the obtained core samples. Additional saturation of core samples with kerosene or water is performed by liquid pump lines system connected to the core holder. In the case of additional nitrogen saturation of the samples, a gas cylinder is connected to the pore pressure line through the reducer. Laboratory studies were carried out to determine the elastic-strength properties of the rock at different saturation.
Keywords
core analysis, elastic-strength properties, various saturation, geomechanics
