Research and Modeling of Nonlinear Acoustic Processes in a Layered Nonlinear Medium with a Porous Fluid-Saturated Inclusion of a Hierarchical Type

Problem statement: The results of the study of seism acoustic emission arising in a porous two-phase geological environment under acoustic influence are presented. Acoustic emission arising in reservoirs of oil fields using good observations is considered. The regularity of the emission processes of acoustic emission, which manifests itself in the form of discrete spectra of signals similar to oscillations of nonlinearly coupled oscillators, is shown. Spectra have special characteristics for each type of rock. Applied method and design: An algorithm for modeling the process of resonant acoustic response of a porous fluid-saturated reservoir with hierarchical structure and plastic properties on acoustic frequency excitation is developed. That algorithm is developed as an iterative process for the solution integral and integral-differential equations. The frequencies that are parameters of the direct problem are used from the spectra of observed data of acoustic emission in the oil wells. Typical results: For the first time, it had been found the relation between resonant frequencies of the acoustic emission and plastic properties, these values of frequencies had been used in the algorithm of modeling distribution of longitudinal waves in the fluid saturated nonlinear plastic environment. Concluding note (Practical value/implications): The analysis of these emission processes can serve as a source of information about the filtration-capacitive properties of productive reservoirs of a porous type with a hierarchical structure. It is used by practical data of oil fields of Western Siberia.

Accounting Hierarchical Heterogeneity of Rock Massif for Prediction of Mine Seismicity

Purpose: When producing mining operations in high-stress rock massive, technogenic seismicity is manifested. Forecasting and prevention of these events is given much attention in all countries with a developed mining industry. From the point of view of the paradigm of physical mesomechanics, which includes a synergetic approach to changing the state of rock massive of different material composition, this problem can be solved with the help of monitoring methods tuned to the study of hierarchical structural media. Changes in the environment, leading to short-term precursors of dynamic phenomena, are explained within the framework of hierarchical heterogeneity and nonlinearity from observations of wave fields and seismic catalog. For that purpose it is needed to develop new algorithms of modeling wave field propagation through the local objects with hierarchical structure. Design/Methodology/Approach: It had been constructed an algorithm for 3D modeling electromagnetic field for arbitrary type of source of excitation in N-layered medium with a hierarchic conductive and magnetic intrusion, located in the layer number J. It had been constructed algorithms for 2D modeling of sound diffraction and linear polarized transversal seismic wave on an anomaly elastic or dense intrusion of hierarchic structure, located in the layer number J of N-layered elastic medium. We used the method of integral and integral-differential equations for a space frequency presentation of wave field distribution. Findings: From the theory it is obvious that for such complicated medium each wave field contains its own information about the inner structure of the hierarchical inclusion. Therefore it is needed to interpret the monitoring data for each wave field apart, and not mixes the data base. Practical Value/Implications: These results will be the base for constructing new systems of monitoring observations of dynamical geological systems. Especially it is needed to prevent rock shocks in deep mines by their exploitation or natural hazards.

Simulation of 2D Nonlinear Manifestations in a Layered-Block Medium with Hierarchical Inclusions

The geological environment is an open system that can be influenced by external and internal factors. They can lead it to an unstable state, which, as a rule, manifests itself locally in the form of zones called dynamically active elements, by which it is possible to identify, on the one hand, potential catastrophic sources that disrupt the technological process when mining the rock massif;оn the other hand, when producing oil from wells, this process can contribute to improving the movement of oil inclusions in the plastic environment of the reservoir. These objects, both in the rock massif and in the oil reservoir, differ from the host geological environment in their structural forms, which are often hierarchical forms. The process of their nonlinear activation can be observed using borehole monitoring of acoustic longitudinal and transversal waves, for the mathematical support of which new 2D modeling algorithms have been developed in that paper using the method of integral and integro-differential equations with the inclusion of nonlinear terms in the dependence of the wave parameter on frequency. When interpreting the results of acoustic monitoring, it is necessary to use the data of such observation systems that are configured to study the hierarchical structure of the environment.

Mathematical Modeling Algorithms for Creating New Materials with Desired Properties Using Nano-Hierarchical Structures

In the enormous and still poorly mastered gap between the macro level, where well developed continuum theories of continuous media and engineering methods of calculation and design operate, and atomic, subordinate to the laws of quantum mechanics, there is an extensive meso-hierarchical level of the structure of matter. At this level unprecedented previously products and technologies can be artificially created. Nano technology is a qualitatively new strategy in technology: it creates objects in exactly the opposite way—large objects are created from small ones [1]. We have developed a new method for modeling acoustic monitoring of a layered-block elastic medium with several inclusions of various physical and mechanical hierarchical structures [2]. An iterative process is developed for solving the direct problem for the case of three hierarchical inclusions of l, m, s-th ranks based on the use of 2D integro-differential equations. The degree of hierarchy of inclusions is determined by the values of their ranks, which may be different, while the first rank is associated with the atomic structure, the following ranks are associated with increasing geometric sizes, which contain inclusions of lower ranks and sizes. Hierarchical inclusions are located in different layers one above the other: the upper one is abnormally plastic, the second is abnormally elastic and the third is abnormally dense. The degree of filling with inclusions of each rank for all three hierarchical inclusions is different. Modeling is carried out from smaller sizes to large inclusions;as a result, it becomes possible to determine the necessary parameters of the formed material from acoustic monitoring data.