Digital core: study of textural heterogeneities in a rock

Relevance. When real fluid flows through channels of limited dimensions, it experiences a constant loss of mechanical energy (hydraulic resistance) due to the action of viscous friction. Hydraulic drag has two components: drag along the length of the flow and local drag. The drag along the length of the flow arises because the fluid encounters a force per unit area perpendicular to the direction of the flow. Local drag results from the viscous interaction between the fluid and the channel walls. Local hydraulic resistances include sudden and gradual constrictions/expansions (diffusers/confusions) of the fluid channel, angular and choke gaps. The value of the hydraulic resistance coefficient depends on the type of channel geometry, conditions of fluid entry (wettability of the rock texture) and on the flow regime. When fluid flows through channels of different cross-section, as the channel narrows, the flow velocity increases and the pressure, based on Bernoulli's equation, decreases. Objects. Polymictic sandstones of the Tyumen Formation. Methods. The developed algorithms for identifying areas of contraction/expansion (confusers/diffusers) in the rock texture (polymictic sandstone) are based on neural network reconstruction of core data. The study of geometric diversity of geological rock images is based on generalization of real spatial forms in combination with the axiom of hyperplanes. A methodical approach for finding distribution of inertial exciters (confusers/diffusers) affecting the character of multiphase flow front changes in the rock texture is based on the metrics for estimating possible distributions. Results. The paper introduces the initial stages of core digital transformation data. It was determined that the main problem of geological data digital projection on a large scale is the need to take into account the systems of inertial effects, both in the available volume of the rock and in the extrapolated space of it. In order to adequately represent the character of multiphase fluid flow for different scales, the authors have developed the algorithms for segmentation of geological images of fluid space with further identification of distribution laws of inertial exciters (confusers/diffusers) in the rock texture. For training and testing of the developed algorithms we used the computer tomography images of core material and detailed resolution images of rock sections. The source code of neural network algorithms was written in the Python programming language with the additional use of non-commercial libraries. The algorithms were tested on real data, confirming by experimental studies in the laboratory of digital research in oil and gas as part of the technological project "Digital Core" (Industrial University of Tyumen, Tyumen), the laboratory of the V.I. Shpilman Research and Analytical Center for Rational Subsoil Use (Khanty-Mansiysk), Core Research Laboratory (University of Tyumen, Tyumen)

ASSESSMENT OF WELL COMPLETION QUALITY IMPACT ON THE VOLUME OF EXPLORED BALANCE RESERVES OF HYDROCARBONS

Link for citation: Katanov Yu.E., Yagafarov A.K., Aristov A.I. Assessment of well completion quality impact on the volume of explored balance reserves of hydrocarbons. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 91-103. In Rus. The relevance. Traditional methods of hydrodynamics are sufficiently unambiguous to find out how much the actual productivity of the reservoir differs from its potential productivity. Such estimation was not quite satisfied with the production, especially in the conditions of exploration works, where the objectives of achieving the potential productivity of the object, as a rule, are not set during the test. The emergence of requirements of economic nature to the results of the test has further limited the scope of its application. There was an urgent need to create such a methodological approach, which would allow assessing the quality of the activities carried out not by discrete values, but on a continuous scale. For this purpose, the authors proposed to use the «desirability» function, which is widely used for quantitative assessment of the quality of any technological processes. The essence of the approach consists in converting the actual indicators into a dimensionless scale of «desirability», which can be used to assess their qualitative level. The main aim of the work is to develop a primary geological and technological model to assess the impact of well completion quality on the volume of explored balance reserves of hydrocarbons. The objects of the investigation are productive sediments of the Pokurskaya, Vartovskaya, Megionskaya, and Vasyuganskaya formations. Methods. The geological efficiency of exploration works on the basis of retrospective analysis was investigated. The relationship between the productivity factor, complex geophysical parameter, underbalance at development and the depth of the bedrock bedding was investigated through associative analysis and mathematical modeling. Geological and technological modeling was carried out to find the optimal underbalance to cause cost-effective hydrocarbon inflow. Results. The well completion quality estimation scheme was formed. Correlations of optimal underbalance level of significance 0,05 were obtained. The «desirability» function was used to translate the actual productivity coefficient to the «quality level», resulting in a system of equations for the minimum cost-effective productivity coefficient

Novel adsorption method for moisture and heat recuperation in ventilation: Composites “LiCl/matrix” tailored for cold climate

Nowadays, advanced technologies for rational use of energy in dwellings have aroused a considerable interest. In cold countries huge amounts of heat and moisture are wasted through the air infiltration due to the large difference between indoor and outdoor temperatures. In this work, an advanced adsorption approach to heat and moisture recuperation in ventilation, called VentireC, is suggested. In this approach, the moisture and sensible heat from outgoing air are absorbed on the adsorbent and heat storing beds and then withdrawn into the inflowing outdoor air, thus, maintaining the indoor temperature and humidity balance. Thermal coupling between two adsorbent beds, which work out of phase, allows latent and sensible loads to be managed separately to enhance the humidity recuperation. For harmonizing the adsorbent properties with the operating conditions of the VentireC process, the requirements for optimal sorbents are formulated based on the thermodynamic analysis of the process. New sorbents based on LiCl incorporated in four matrices with the various mesoporous structure are synthesized and investigated. The water sorption/desorption equilibrium for the most promising sorbent is reported. This composite exchanges over 0.5 g-H2O/g under a typical VentireC cycle, which is promising for effective heat and moisture regeneration