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Date submitted2021-04-19
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Date accepted2021-10-18
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Date published2021-12-16
Mutual spectral densities calculation of the moments of resistance on the peat milling unit working bodies
- Authors:
- Konstantin V. Fomin
When performing technological operations in the peat industry, various units with milling-type working bodies are used. They differ in design, layout, number and type of cutting elements, operating modes, and may have one or more working bodies. During operation, random forces and moments act on the cutters, which have a dramatically variable nature, which is associated with the periodic interaction of the knives with the peat deposit, its structural heterogeneity, variations in the milling depth, physical and mechanical properties of peat, the rotational speed of the cutter and the movement speed of the machine. In this case, significant dynamic loads arise in the structural elements, which leads to a decrease in their reliability, deterioration of the energy characteristics of the engine operation and technical and economic indicators of use. In the dynamic analysis of drive elements, when using machines with several working bodies, it is necessary to know both spectral and mutual spectral load densities. For their calculation, expressions were obtained that take into account the physical and mechanical properties of peat, the operating modes of the unit and their probabilistic characteristics, as well as the design features of the working body. The expressions are obtained for the case when there are several working bodies with the same diameters and the number of knives in the cutting plane. In this case, the number of planes, width, type of cutting element and type of cutting (locked, semi-locked, etc.) may differ. As an example of using the developed approaches, the calculation of spectral and mutual spectral densities of moments on cutters and loads in the drive elements of the machine for surface-layer milling MTF-14 is presented.
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Date submitted2019-05-14
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Date accepted2019-07-05
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Date published2020-04-24
Development of spacer fluids and cement slurries compositions for lining of wells at high temperatures
Article is devoted to creation of new compositions of process solutions for lining of directional wells at high temperatures. Developed compositions provide high durability characteristics of cement stone. It is shown that with an increase in packing density of cementing slurry components durability characteristics increase and porosity and permeability of cement stone decrease, whereas an increase in temperature and pressure leads to a significant increase in compressive and bending durability, which is associated with presence of quartz in them. It has been established that introduction of special structure-forming additives to the composition of developed cementing solutions allows formation of sedimentation-resistant cement systems that can provide an increase in durability characteristics of cement stone and, in general, quality lining of directional wells. Study of rheological properties of developed cementing compositions showed that the systems have high yield strength at increased temperatures and pressures. Developed compositions of water-based spacer fluids increase the cleansing degree for both casing and rocks surfaces from mud and clay cake residues, which improves the cementing quality of oil and gas wells. Mechanism for increasing the washing ability of spacer fluids and durability characteristics of cement stone, depending on composition and properties of their constituent components, is disclosed.
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Date submitted2019-06-19
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Date accepted2019-09-11
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Date published2020-02-25
Method for estimating the spectrum density of the resistance moment on the working body of a peat milling unit
- Authors:
- K. V. Fomin
The main source of dynamic loads in the drive elements and the design of the peat milling unit is the working body. The forces of external resistance arising in the process of performing a technological operation are sharply variable, random in nature. The article proposes a model of formation of the moment of resistance on the mill when interacting with peat. The case when there are several cutting planes with the same radius at the ends of the cutting elements is considered. When developing the model, it was taken into account that the operating conditions of the knives, determined by the type of cutting (blocked, semi-blocked, etc.), their width and type in each cutting plane can vary. Factors that determine the nature of loading, such as the frequency of interaction of the cutting elements with the fallow and the randomness of the operating conditions of the unit, lead to the presentation of the loads in the form of a sequence of pulses with random parameters. Expressions are obtained for determining the spectral density of the moment of resistance on the mill at the design stage, taking into account its design, operating modes, physico-mechanical properties of peat and their probabilistic characteristics. To illustrate the application of the developed approaches, a technique is presented for determining the spectral density of the moment on the working body of deep milling machines and in their drive elements based on a linear model. An example of calculation is given, and the obtained expressions are verified on the basis of experimental data. The probabilistic characteristics of the loads on the mill serve as initial information for the dynamic analysis of the drive system and the design of the unit, its strength analysis, the selection of optimal parameters and operating modes.
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Date submitted2018-01-01
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Date accepted2018-03-24
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Date published2018-06-22
Complex petrophysical correction in the adaptation of geological hydrodynamic models (on the example of Visean pool of Gondyrev oil field)
- Authors:
- V. A. Repina
- V. I. Galkin
- S. V. Galkin
The authors review a method of combined porosity and volume density correction in the process of modeling the distribution of reservoir permeability. Basing on petrophysical investigations of core samples from Bashkir fold deposits, an association between rock porosity, density and permeability has been analyzed. Significant correlation has been observed for the above mentioned parameters in porous collectors in contrast to reduced correlation for dense rocks and intervals of anomalously high poroperm characteristics. For terrigene porous collectors the authors propose a model of permeability assessment based on combined porosity and density correction. A modified model was developed for Visean pool of Gondyrev oil field, where collector permeability had been calculated as a function of rock porosity and density. The modified model has been compared to the conventional one; significant differences have been detected. In the modified version maximum permeability is associated with the southern part of the pool, whereas the conventional method points out the central part and predicts lowering permeability closer to the periphery. Geological model in the modified version is more homogenous than the conventional one and has no sharp peaks and valleys. The calculations have been made that reproduce the history of field development for both permeability volumes. Authors demonstrate that total oil production obtained using the modified model has a much better correlation with the actual data. The best results from using suggested method apply to the initial stage of development due to better convergence of high-rate wells. On the whole, comparison of two methods shows that for the purposes of production history adaptation the modified model is significantly better than the conventional one. Hence, the method of density correction allows for better justification of differences in the lithology of Visean collectors, which ultimately results in higher accuracy of data on residual oil reserves in the deposit.