Prospects for the application of proppant hydraulic fracturing at Kashiro-Verey operational facilities Volga-Ural oil and gas province

The geological structure of Kashiro-Verey carbonate deposits is considered on the example of one of the deposits of the Perm Region. By combining geophysical studies of wells, standard and tomographic studies of core, the following lithotypes of carbonate rocks were identified: highly porous cavernous, layered heterogeneous porous, heterogeneous fractured porous, dense. It was found that for heterogeneous lithotypes, the porosity estimate in the volume of the permeable part of the rocks significantly exceeds 7%. Experiments on the destruction of rocks were carried out for the selected lithotypes. As a result, it was found that cracks do not form for samples of the cavernous lithotype at a compression pressure of 20 MPa. For a compacted lithotype, already at a compression pressure of more than 10 MPa, an intensive development of fracturing occurs. As a result of multiaxial loading of cores, which can be considered as analogous fracturing of the formation, wide fractures are formed, along which filtration of fluids can occur. Keywords: proppant hydraulic fracturing; X-ray tomography of the core; porosity; permeability; fractured reservoir; oil deposit; carbonate deposits.

A resource efficient and environmentally safe charge structure for mining in an open-pit

Purpose. The purpose is to reduce mineral losses during the explosive destruction of rocks and environmental pollution by harmful gases and fine particulate matter. Methods. To achieve the objectives of the study, methods of physicochemical analysis and mechanics of continuous media have been used. The method of physico-chemical analysis has been used to determine the quantitative and qualitative characteristics of the composition of the well stemming depending on the parameters of the well, the type of explosive, the amount and type of harmful gases formed during the explosion. Methods of solid medium mechanics have been used to establish the patterns of pressure waves during an explosion depending on the characteristics of the gap filler between the charge and the well wall. To solve the problem of the behavior of a two-layer medium during the loading of a cylindrical cavity by a nonstationary load, a numerical method based on the finite-difference McCormack predictor-corrector scheme has been used. Findings. A resource-saving and environmentally friendly charge structure for rock mining by explosion was developed. The design of the charge involves the formation of a gap between the charge and the wall of the borehole, and filling it with a suspension of calcium hydroxide or a suspension of calcium carbonate. Originality. SThe dependences of the volume of harmful gases (NO2, CO2, CO) formed during the explosive destruction of rocks and the magnitude of the pressure peak in the area close to the charge on the chemical composition of the filler of the radial gap between the charge and the well wall have been set. Practical implications. Developed charge design allows to neutralize the harmful gases formed during the explosion, to reduce the pressure peak in the area of the rock massif close to the charge, and can be widely used in non-metallic quarries that extract minerals for the production of crushed stone.

CHANGE OF ENERGY CHARACTERISTICS OF LITHOSPHERE ELEMENTS DURING THEIR DEFORMATION

Purpose. The purpose of this study is to establish analytical patterns for predicting changes in stress and energy density spent on the destruction of rocks according to experimental studies. To solve this purpose in the article were set the following scientific problems: 1) analytical description of the dependence of the stress σij on the main deformation εij; 2) establishment of calculation parameters that are included in the analytical patterns; 3) analytical description and study of fracture energy density curves. Methodology. In the course of analytical and experimental researches of full diagrams of deformation of rocks the mathematical model of dependence of the stress on the deformation is developed. Physico-mechanical processes of all characteristic sections of the complete deformation diagram were also analyzed and described. Analysis of the resulting curve showed that the rock mass and elements of the lithosphere are not perfectly elastic or plastic objects. Along with the elastic ones, plastic ones are always present to one degree or another. The integration of the obtained analytical expression σ11 = f(ε11) allowed to establish the volumetric energy density spent on the destruction of the rock sample under the action of external load. The maximum activation energy for the considered rock is 0.67 MJ/m3. A comparison of the experimental and calculated values of the energy dependence u(ε1) shows a coincidence over almost the entire range of deformation changes (ε11 = 0..0.04). Findings. The study of rock samples at hard stress allowed to obtain a complete deformation characteristics of the rock. The curve that surrounds the deformation cycles (1) combines pre-boundary, boundary, extremal modes of deformation and destruction of rocks. Equation (4) allows us to establish that the destruction can occur at different values of energy density U(ε). Originality. An analytical description of the energy diagram of deformation and a complete diagram of stress change in the form of a single dependence, which takes into account the boundary and extremal areas, was developed in the work. In contrast to the method of piecewise linear approximation, this approach corresponds to the physics of the process and reduces errors in calculations. Practical implications. Theoretical and experimental analysis of the obtained energy fracture diagrams and complete stress change diagrams in rocks allows to estimate the bearing capacity of a rock mass or other solid body. This allows you to predict critical values of stresses and external loads to prevent failure in a timely manner.

The influence of flushing fluids rheological properties on rock breaking efficiency when drilling wells by pellet impact drilling method

Introduction. Pellet impact drilling method which is basically the destruction of rocks by blows of pellets, has been studied by many researchers. Despite this, the rheological properties of the drilling fluid used in pellet impact drilling have not been investigated yet. All bench and field tests were carried out using service water. The use of a drilling fluid with a higher viscosity than water has the potential to expand the field of application of pellet impact drilling. Therefore, it becomes urgent to study the effectiveness of destruction of rocks when using flushing fluids with different rheological parameters. Objective of this research is to investigate the efficiency of rock destruction in the process of drilling wells using the pellet impact drilling method at various rheological parameters of the drilling fluid. Methods of research. A scaled laboratory bench was used in the research. The bench was a closed system of circulation of the drilling fluid (drilling mud). The solution was prepared separately on a high-speed mixer. The main part of the bench was a scaled pellet drill bit located in a simulated well. After the experiment, the destructed rock volume and the rheological parameters of the flushing fluid were measured. A series of experiments was carried out with a gradual increase in the viscosity of the flushing fluid. A biopolymer (xanthan gum) in various concentrations was used to thicken the flushing fluid. Drilling fluid rheological parameters were measured using an eight-speed rotary viscometer and a Marsh funnel. Results. For the first time, a relationship has been established between the efficiency of rock destruction during pellet impact drilling and the rheological parameters of the drilling fluid used. It was found that with an increase in the concentration of biopolymer and an increase in viscosity, at first, there was a significant increase in the volume of drilled rock per unit time, and with a further increase in concentration, a gradual decrease occurs. Conclusions. The results obtained expand the field of application of pellet impact drilling. The reliability of predicting the drilling speed is improved depending on changes in the properties of the drilling fluid. Based on the results, recommendations were made for the selection of the optimal parameters of the drilling fluid, depending on the drilling conditions.

Physical and mathematical model of rock destruction by a milling machine cutter

As a result of the analysis of the work on rock destruction by cutters of milling of machines, it was found that the existing developments do not allow us to proceed to the derivation of calculation d dependencies for determining fracture resistance, or can be used only in preliminary calculations of the known by design parameters of milling machines. To eliminate these disadvantages, a combined physical and mathematical model of the process of interaction of a single milling cutter with a spherical tip with the rock has been developed. Consideration of the physical picture of the action of forces and stresses acting from the cutter with spherical tips on the separating rock element in the limiting condition allowed to describe analytically the components of total resistance, which are the mathematical part of the physical and mathematical model of rock destruction by cutters. Analytical dependences for determining the tangential and normal components of fracture resistance of rocks of medium hardness have been obtained. The adequacy of the physical and mathematical model to the physical process of destruction of rocks of different hardness by cutters on a universal stand was tested both in the field and in the laboratory conditions. Technical evaluation of the results of experimental studies confirms the reliability of the developed physical and mathematical model.

The Life of Volcanic Rocks During and After an Eruption

Volcanoes are constantly growing and changing. Every time a volcanic eruption occurs, new rock is added to the surrounding area. These eruptions play a big part in the formation and destruction of rocks as well as in shaping the Earth’s surface. Yet, we do not know everything about the histories of the volcanoes that previously existed on Earth. Volcanologists—scientists that study volcanoes—can study the types of rocks that volcanoes produce, to gain a better understanding of volcanoes. These rocks vary based on the characteristics of the volcano from which they came. Volcanic rocks are unique because we can study them to accurately discover when and how they were formed. In this article, we explain the processes that make volcanic rocks and formations look different from each other. We also discuss ways that volcanologists can determine how ancient volcanoes were made, by studying the rocks produced during past eruptions.

STUDIES OF THE SHAPED CHARGES EFFECT WITH A HEMISPHERICAL ECCENTRIC SHAPE RECESS FOR THE ROCKS DESTRUCTION

The method of outdoor installation of explosive charges is usually used in the destruction of rocks in conditions in which the method of drilling and blasting using borehole or borehole charges is difficult to apply due to objective conditions. The productivity of rock destruction by the outdoor installation of a concentrated charge is very low. This is due to the fact that such an explosion is characterized by a large loss of energy in the environment. The destruction of rocks by an explosion using shaped charges (CW) to destroy the rock is one solution to increase the useful energy of the destruction of the rock compared to charges placed outside. To achieve the optimal effect of destruction of the rock by cumulative charges, it is necessary to, so that for each type of rock, a specific type of shaped charges can be determined with the appropriate performance and efficiency of the use of explosives. The stronger the rock, the more efficient the short-circuit should be, and vice versa. Thus, for effective rock crushing, it is necessary to develop and produce a number of different types of shaped charges. The use of shaped explosive charges allows you to increase the utilization rate of the useful energy of the explosion and increase the destruction zone of the rock. At a fixed mass of the explosive, the destructive effect of the explosive charge placed on the surface of the rock, it depends on the shape of the charge and the geometric parameters of the charge. Shaped charges with an eccentric hemispherical shape have a coefficient of use of the useful energy of the explosion for the destruction of rock, more than 2.4 times compared to conventional concentrated charges of the same mass.

DEVELOPMENT OF THE MECHANISM OF ACTION OF DECONCENTRATED CHARGES OF VARIOUS SHAPES FOR VARIOUS MINING CONDITIONS

The modern requirements of the market economy and the increasing complexity of the field development conditions require new scientific and technical approaches in deep quarries and mines in the complex development of subsurface resources. As you know, the dominant mining paradigm in drilling and blasting is associated with the technique of drilling wells and boreholes of a circular shape (cavity) with the placement of explosives in it. However, in mining science and practice, the variety of mining conditions has long required the creation of methods for the destruction of rocks with an asymmetry in the distribution of explosion energy in space and its maximum concentration in certain directions. In this regard, we consider a conceptual direction based on a fundamentally new mechanism of action of the explosion of known groups of parallel-converged borehole charges, which effectively expand their use in various mining applications. The development of a new mechanism of action of the explosive process with the use of a computer program and numerical simulation of calculations made it possible to use the change in the shape and design of the charge as a means of increasing the share of the energy flow of the explosive explosion in a certain direction. The design of the deconcentrated charge is shown as a means of increasing the fraction of the energy flow of the explosive explosion in a given direction, which leads to a significant increase in the efficiency of the directed explosion and, in particular, minimizes its action in the opposite," legit", direction. Based on the results of the research, a method of blasting operations is proposed to neutralize the influence of anomalies in the state of the massif on mining operations by the explosive method. The method includes the appropriate tools, characterized by an unconventional design of the borehole charge and using a mechanism for influencing the anomalous states of the array with a combination of its explosive features.