The Study of Filtration and Capacitive Properties of Rocks during Filtration of the Saltpeter Solution in the Technology of Thermo-Gas-Chemical Impact on the Reservoir

About the authors:

Boris V. Grigoriev, Cand. Sci. (Tech.), Associate Professor, Department of Applied and Technical Physics, Institute of Physics and Technology, University of Tyumen; b.v.grigorev@utmn.ru

Igor R. Potochnyak, Laboratory Assistant, Laboratory of Digital Research in the Oil and Gas Industry, Scientific and Educational Center for the Development of Scientific Competencies, Industrial University of Tyumen; Assistant Professor, Department of Applied and Technical Physics, Institute of Physics and Technology, University of Tyumen; i.r.potochnyak@utmn.ru; ORCID: 0000-0002-4263-711X

Abstract:

The influence of a binary solution of ammonium nitrate on the filtration-capacitive properties of core samples has been investigated. Several series of experiments have been consecutively performed. Each series has been carried out under given reservoir conditions using the method of stationary two-phase filtration. In the first series, the relative phase permeability curves (RPT) were obtained during the filtration of the formation water and oil model; in the next stage, one of the two components of the binary mixture, a concentrated solution of ammonium nitrate, was injected into the reservoir, that is, the physic-chemical properties of the reservoir were changed, after which the experiment of two-phase filtration "the model of formation water-oil" was repeated. As a research object, terrigenous and carbonate samples of core material were taken. Each series of experiments for the same samples was preceded by extraction, drying, saturation with formation water, centrifugation under identical conditions; the thermodynamic conditions for the experiments were the same. It has been established that a 60% solution of ammonium nitrate has a different effect on the relative phase permeability of rocks, depending on their lithological composition. So, for carbonate rocks water permeability has increased, and for oil it has slightly decreased, while for terrigenous rocks it has significantly decreased for both phases. This phenomenon could be explained by the formation of new minerals at the contact of saltpeter with the mineral skeleton, primarily carbonate rock, at high pressure and temperature. The mineral composition of the sample obtained by prolonged evaporation at the temperatures of 75-105 °C of a saltpeter solution with the main rock-forming mineral of carbonate rocks, calcium carbonate, was determined by X-ray diffraction analysis. The results of decoding the diffractograms showed the absence of new crystalline structures besides the initial ones, which excludes the chemical factors of the influence of saltpeter on the minerals of carbonate rocks.

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