Investigation of the influence of gravel stuffing in an open drill on the productive characteristics of the well

The negative consequences of sand production from the formation into the wellbore during the operation of wells with unstable rocks are characterized. A highly effective method of preventing sand from entering the well from the formation is the use of gravel packs, which are used in Ukraine and abroad. The types of gravel packs, the conditions for their application, the choice of the diameter of gravel grains for creating gravel pack are given. The types of gravel pack installation are considered depending on the geological and technical conditions of the reservoir. Calculations have been performed using Schlumberger's PipeSim software to assess the effect of gravel pack size and permeability on the performance specification of a gas well. Based on the research results, graphical de-pendences of gas flow rates in the presence of gravel pack on the permeability of the gravel pack at its various thicknesses have been constructed and analyzed. It has been found that the gas flow rate increases with an increase in the thickness of the gravel pack in the considered interval of its variation up to 0.9 m. The effect of the thickness of the gravel pack on the gas flow rate increases with an increase in its permeability. Based on the results of statistical processing of the calculated data using the least-squares method, the optimal values of the gravel pack permeability for various values of its thickness have been determined. The optimal values of the thickness and permeability of the gravel pack have been determined, beyond which the value of the gas flow rate practically does not change. The calculation of the pressure distribution along the bore of a gas well in the presence of gravel pack with certain optimal values of its permeability and thickness is performed. Using the PipeSim software, the influence of the de-gree of relative formation penetration on the productivity of a gas well in the presence of gravel packing has been investigated for determining certain optimal values of permeability and thickness of gravel packing.

Technology of conversion of materials of power and oil refining objects

Quantitative and qualitative characteristics of multi-ton materials in Ukraine and in Ivano-Frankivsk region, which Quantitative and qualitative characteristics of multi-ton materials in Ukraine and in Ivano-Frankivsk region, which contain energy components, are given. It is proposed to process water treatment sludges containing petro-leum products by preparing a raw material mixture from the following man-made substances: oil sludge, ash, zeo-lite screenings, calcium-containing compounds and viscous materials. The optimal composition of the raw material mixture is as follows: as a filler for construction products (concrete): ash – 60-65 %, liquid glass s olution – 5-7 %, limestone dust – 3-5 %, organic additives – 7-10 %, soda ash – 10-12 %, which is granulated and heat t reated at 120-140 °C. The research results and technical char acteristics of the obtained granular materials, which are formed from a mixture containing a significant amount of hydrocarbon sludge, have lower strength, but greater porosity and lower thermal conductivity. Granules from a mixture № 4-7 are characterized by higher strength, and due to their properties they belong to the structural and thermal insulation materials. The technology of obtaining a raw material mixture for soda production is based on the LeBlanc process – the interaction in the seco nd stage of sodium sulfate, carbon and calcium carbonate with the formation of calcium sulfide, sodium carbonate and carbon (IV) oxide. It is proposed to prepare a raw mixture for the production of sodium carbonate from sodium sulfate con-taining petroleum product, which is formed by the technology of obtaining oxygen-containing additives, and sludge containing petroleum products, which will provide a high temperature during the soda production process. The processing of sludge from oil refining and energy facilities into granular materials shows that they can be used in the construction industry and soda production, which reduces the energy consumption of the processes of obtaining such materials.

Effects of the rate of carbon dioxide injection at the initial gas-water contact on the recovery factor

The process of carbon dioxide injection into the initial gas-water contact with different rates of its injection, using a 3D model of a gas condensate reservoir, has been investigated. Calculations were carried out for one well injection rate of non-hydrocarbon gas: 40, 50, 60, 70, 80, 90 th.m3/day. According to the calculated results, it has been found that with an increased rate of the carbon dioxide injection into a productive reservoir, the operation duration of production wells decreases until the moment of the carbon dioxide breakthrough. Based on the techno-logical indicators’ analysis of the gas condensate reservoir’s development, it has been found that the introduction of the carbon dioxide injecting technology leads to a reduction in the production of formation water. Due to the injec-tion of non-hydrocarbon gases, a hydrodynamic barrier is created on the initial gas-water contact boundary, which decreases the water influx. Also, the introduction of carbon dioxide injection technology will additionally create an artificial barrier between water and natural gas, which blocks the selective water encroaching and thereby ensure stable waterless operation of production wells. Based on the conducted calculations, the main dependencies have been derived and the corresponding patterns between them have been established. According to the results of the statistical processing of the calculated data, the optimal carbon dioxide injection rate has been determined. At the time of the carbon dioxide breakthrough into the producing well, its optimal well injection rate is 58.17 th.m3/day. The ultimate gas recovery factor for the optimal carbon dioxide injection rate is 63.29 %. Under the same condi-tions during depletion, the ultimate natural gas recovery factor is 53.98%. The results of the carried out studies indicate the technological efficiency of carbon dioxide injection into the initial gas-water contact in order to slow down the formation water encroaching into productive reservoir.

Generalization of the basic research on the increase of recovery factors in water-drive gas-condensate reservoirs

The problem of monitoring and preventing deposit inundation is becoming increasingly important in Ukraine. The solution to this problem is one of the ways to ensure the energy independence of the state. The operation of producing wells is complicated by the accumulation of liquid at the bottom. Subsequently, it leads to premature shutdown of the wells. Inundation determines the need to isolate the influx of formation water. Considering the significant residual reserves of gas trapped in water, it is important to improve existing technologies and to develop new ones for the development of depleted fields under the conditions of dynamic water drive in order to ensure maximum hydrocarbon recovery rates. This paper summarizes domestic and foreign field development technologies under water pressure conditions and analyzes the main disadvantages and advantages of the existing methods of stimulating hydrocarbon inflows in waterlogged gas and gas condensate wells. The main factors that determine the causes and nature of flooding of productive formations and ways to prevent them are analyzed. Based on the results of the analysis of laboratory and experimental studies, the behavior of gas trapped by brine water has been established.But the issue of determining the localization of residual reserves has not been studied sufficiently. Considering the above mentioned ideas, the author asserts the necessity to and to use geological and technological models constantly. It ensures better extraction of the residual gas from depleted fields under the condition of intensive advance of reservoir water into productive formations. In the case of adapting the three-dimensional model to the actual data of the production history and the simulation of the exact breakthrough of produced water in production wells, there comes the possible to determine the most promising zones and sections of the field, the reservoirs of which are characterized by the best filtration-capacitive properties and significant gas reserves. The use of a constantly operating geological and technological model of the field will make it possible to develop ways of extracting the residual gas reserves trapped in produced water, to improve existing production technologies and to ensure maximum recovery factors.

The influence of contamination of the bottom-hole formation zone and the of perforation channels parameters on the productivity of gas wells

The reasons and nature of contamination of the bottomhole zone of wells are characterized. The structure of the skin effect is revealed. The characteristics of the types of well completion and the main parameters that are necessary to determine the skin effect are given. For the conditions of a hypothetical well, using the PipeSim program from Schlumberger, the influence of the permeability and thickness of the contaminated bottomhole formation zone on the value of the skin effect is investigated. The graphical dependences of the skin effect of the contaminated zone on its thickness and permeability are shown. The results of graphical dependencies are processed using statistical analysis. According to the research results, the value of the skin effect increases with the decrease in the permeability of the contaminated zone relative to the permeability of the productive formation and with the increase in the radius of the contaminated zone. The improvement in the filtration properties of the bottomhole formation zone occurs with the increase in the permeability of the contaminated zone compared to the formation permeability. The optimal values ​​of the permeability and thickness of the contaminated zone are obtained, above which the skin effect practically does not change. The study of the influence of the quantity and size (length and diameter) of perforation channels per one meter of the open layer thickness is carried out. The research results are shown on the graphical dependences of gas flow rate and bottomhole pressure on the number of perforations per one meter of the open formation thickness, their length and diameter. The use of perforation channels that pass through the conta-minated zone has been substantiated to improve the hydrodynamic connection of the formation with the well and increase the gas production rate. According to the results of studies carried out using the McLeod model, the optimal diameter of the perforation channels is 0,029 m, the length of the channels is 0,296 m, and the number of channels per meter of the open formation thickness is 16.

Simulation of kerogen evolution by thermodynamic methods (on the example of Southern oil and gas region)

The article considers the methods for estimating the level of organic matter transformation, scattered in sedimentary strata, in the process of catagenetic transformations. The authors show the efficiency of kerogen property research by coal petrographic methods and palynological analysis, the purpose of which is to establish the paleotemperature that was actualized in the process of evolution. The advantages and disadvantages of establishing the organic matter generation potential by pyrolytic methods, primarily by pyrolysis by Rock-Eval, are evaluated. In the context of the organic matter evolution indirect study methods, brief information on gas geochemistry is given and the main indicators used in the analysis of the chemical composition of gases in hydrocarbon deposits are listed. It is shown that the equilibrium thermodynamics apparatus can provide information about the conditions and level of organic compounds transformation in the lithosphere. The general information on geological history of the Southern oil and gas region of Ukraine is given and the main events that influenced the modes of transformation of organic matter are shown. The most important of these were the plate collision processes and the accompanying spreading that took place during the approaching of the Arabian continent and Eurasia, which led to the formation of a faults network: submeridional and sublatitudinal. According to the chemical composition of the region's depo-sits, graphs within the coordinates C2/C3 to C2/i-C4 and ln(C2/C3) to ln(C1/C2) are plotted. According to the graphs, the authors establish the trends of organic matter evolution: development in the direction of maturation and kerogen formation without secondary oil destruction. Information on the method of calculating the kerogen/gas system composition according to the Jaynes formalism is given. According to thermodynamic simulation combined with the chemical composition of deposits, maps of equilibrium temperatures and depths for several temperature flows are constructed. The effect of the individual deposits geological structure on the evolution of its contents is shown. The map of generation depletion of the region kerogen is made. According to the results of the map analysis, it is found that the kerogen of the Kerch-Taman interpericline depression is maximally depleted, while the kerogen of the southern side of the Karkinitsky-North-Crimean depression retains the high potential for the formation of light hydrocarbons.

Abnormal stresses in underground pipeline due to static and dynamic reversal of several foundation blocks

The article discusses the issues of forecasting the strength of underground pipelines laid in seismically active areas through sections composed of relatively rigid moving blocks. In such dangerous areas, in addition to the normal pressure load of the transported product, the pipe is subjected to additional effects from the movements of the fragments of the block foundation. As the literature data show, the problems of the influence of the interaction of faults on the stress state of the pipeline have not yet been studied. The aim of the study is to develop a model for the analysis of abnormal stresses in the underground pipeline on a damaged foundation caused by static or time-harmonic reciprocal turns of the blocks around the axis of the pipe on both sides of several faults. Static equilibrium and harmonic oscillations of the pipeline are investigated in a linear setting, modelling it with a rod with an annular cross section. The inertia of the transported product is not taken into account. To consider the issues of the ultimate equilibrium of the pipe, the momentless theory of shells and the energy theory of strength are used. The soil backfill is considered as Winkler’s elastic layer. Multiple damages to the solid foundation are presented in the form of several faults on which there is a rupture of the angle of rotation around the axis of the pipe. We formulated boundary value problems for differential equations of static torsion and torsional harmonic oscillations with discontinuous right-hand sides. Based on the analytical solutions of these problems for the cases of antisymmetric and symmetrical reversal of the foundation blocks, the distributions of the torsion angle and equivalent stress in the pipe, depending on the distance between faults and the frequency of forced oscillations of the system, are investigated.

The analysis of factors influencing the trajectory of the vibrating screen

Due to the fact that the shape of the trajectory of the sieve vibrating screen significantly affects the efficiency of cleaning the drilling mud from the drilled rock, this article identifies and analyzes the factors influencing the formation of the trajectory of the sieve. The study of the nature of the motion of the particles of the drilled rock is carried out. The motion-equation of the point of the jigging frame, respectively, and a certain section of the screen can be described by an non-homogeneous second-order differential equation (Newton equation). The equation of the trajectory of the jigging frame is also considered. The influence of the amount of drilling mud, which is on the vibrating screen at a certain time-point, on the trajectory is taken into account in this equation. The drilling mud complex system consisting of liquid and solid fractions – sludge, sand and sludge – is taken into account. In this case, the fluid and clay move without separation from the sieve, and sludge and coagulated clay – with separation from the transport surface. Depending on the position on the sieve, each component of the drilling mud at different time periods moves with different trajectories and different other variable parameters along the length of the sieve. Therefore, the main purpose of the research is to obtain a graphical real trajectory of the selected point of the jigging frame of vibrating screens, to compare it with theoretical graphical dependences and to establish parameters that affect the change in the amplitude of jogging frame vibrations in real operating conditions. The coverage of the problem and the main results of the research are performed in real conditions (when vibrating screens work on the drilling rigs). The research is performed using simple recording devices installed at six places – on the left and right sides of the jigging frame above the front and rear shock absorbing springs, and in the center of stuff – between springs. All the real trajectories of certain points of the jigging frame and screen can be described using certain Lissajous figures. However, it was found that not all trajectories coincide completely with the classic Lissajous figures, because the trajectory is influenced by external factors that cause chaotic motion of the jigging frame – the Sommerfeld effect, as well as non-uniformity of drilling fluid delivery. The nature of the movement of the vibrating plane - the screen - is also affected by the rigidity of the vibrating support, including the entire structure of the vibrating screens. The phenomenon of resonance is possible in the area of ​​vibration supports. In addition, it was previously established that the trajectory of the point of a certain area of ​​the screen is a spatial figure that requires additional theoretical and experimental studies. When moving the drilling fluid on the sieve with the toss, the cleaning efficiency will be much higher due to the increase in vibration force. Based on the analysis of the results of the factors influencing the trajectory of the sieve, preliminary recommendations are given for the correct adjustment of the vibrating screen.

The investigation of the stress-strain state of beam crossings with a truss-form supporting element of the operating pipeline

The areas of application and advantages of the over-ground piping or pipe section layout are given. The classification according to the design features of the most common systems of overhead pipeline crossings on the basis of generalization of scientific publications and experience of pipeline construction are considered. The authors indicate the ranges of the effective spans for rectilinear single-span and multi-span crossings without compensators of longitudinal strains (with the fixed ends) and also in multi-span systems with compensators depending on the diameter of pipes, nominal pipe wall thickness and brand of pipe steel for gas, oil and oil-products pipelines respectively. The description of the design of beam systems of overhead pipeline crossings with a truss-form supporting element of the operating pipeline is given and the procedure for estimating their stress-strain state is suggested. According to the constructed cargo and unit calculation schemes of the truss with a cross-section in the form of an isosceles triangle (height – 3 m, width – 2.02 m) the stiffness coefficients of elastic-malleable supports is determined. The selection of cross-sections of truss members is carried out, the required deflections of the pipeline and the emerging internal force factors (bending moments and reactions of elastic-malleable supports) at the points where the pipeline rests on the truss are found. The strength of the pipeline to the action of the maximum bending moment is checked and the possibility of the cross-water layout of the beam crossing of the gas pipeline is shown. This is the gas pipeline with the length of . It has compensators with a truss-form supporting element which eliminates the use of intermediate supports. Thus, it was shown that the truss makes it possible to double or triple the length of the span using no intermediate supports and preserving sufficient horizontal rigidity.

Improvement of the transfer function quality indicators of the power control system at the electric drill engine shaft

In order to get better rigs performance the authors improve the schematic diagram of the power control system at the electric drill engine shaft using control input transfer function, where the electric drill is considered to be the control object which operates in conditions of a priori and current uncertainty under the influence of external perturbations. To improve the quality of the transient process under the conditions of changes in the parameters of the control object (when these parameters cannot be checked on), the authors have developed the algorithm of tuning the adaptive fuzzy PID controller based on the hybrid adaptive system. This algorithm includes the advantages of artificial neural networks and fuzzy logic. The efficiency of the algorithm with the parametric disturbance has been shown. It is concluded that the implementation of adaptive fuzzy PID controllers makes it possible to improve the quality of the transfer function of the power control system at the electric drill engine shaft when this drill operates in the indefinite conditions. The advantage of the developed algorithm is that it does not require special methods of the object parameters identification. Its implementation using modern microcontrollers is quite simple and accessible.