Drilling fluid circulation rate influence on the contact temperature during borehole drilling

Kozhevnykov, Anatolii; Dreus, Andrii; Лиу, Баочанг; Sudakov, Andrii

doi:10.29202/nvngu/2018-1/14

Cited by 11 publications

(10 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Curve 6 in Fig. 3 describes the dependence (17). The find ings show that as the Bi number increases, the solutions ob tained using the proposed model, approach the solution de scribed by the (17).…”

Section: = -mentioning

confidence: 83%

See 1 more Smart Citation

Approximate analytical model of rock thermal cyclical disintegration under convective cooling

Dreus¹,

Kozhevnykov²,

Лиу³

et al. 2019

NVNGU

Self Cite

View full text Add to dashboard Cite

Purpose. Development of an approximate analytical method for calculating strength reduction of different rocks under thermal cycling effects, taking into account the intensity of convective heat transfer. Methodology. To solve the problem, an analytical approach based on the thermoelasticity theory was used within the frame work of the Griffiths model of fragile fracture. Findings. It is demonstrated, that cooling of the previously heated rock formation stipulates for intensifies of the rock decom position process, due to developing fractures zone and decreasing rock strength. Methods for calculating were developed and effect of the intensity of convective heat transfer on crack opening processes in the rock was studied. The results of calculation of destruc tion time lag for various rocks are presented. It is shown that the efficiency of thermal cyclic decomposition depends on the type of rock. Originality. A new approximate analytical approach to the investigation of the development of initiated cracks in mining rocks under thermal cyclic load and cooling applied to the surface is proposed. An analytical expression has been obtained for the rela tionship between the parameters of the fracture process and the parameters of the cooling process. Theoretical substantiation of the use of variable thermal effects on the rock to improve the efficiency of rock destruction during drilling has been carried out. Practical value. The outcomes of the study can be used to estimate of the parameters of the heat exchange processes to provide effective rock disintegration during drilling. The studies carried out confirmed the possibility of control of the temperature mode on the working face and thermal softening of the rock by changing the flow rate of the drilling fluid.

show abstract

Section: = -mentioning

confidence: 83%

“…Thus, under normal flushing conditions, the temperature difference at the bottom is up to 300 °С, which is not enough to effectively realize the thermal cyclic effect. However [17], the use of pulsed flushing modes allows a temperature difference of 600 °С to be reached.…”

mentioning

confidence: 99%

Approximate analytical model of rock thermal cyclical disintegration under convective cooling

Dreus¹,

Kozhevnykov²,

Лиу³

et al. 2019

NVNGU

Self Cite

View full text Add to dashboard Cite

show abstract

“…This makes possible to increase the rational depths of application of the roof-bolting and combined roof-bolting in preparatory mine workings, and also to exclude the application of expensive frame or concrete supports in preparatory mine workings [30,31]. At the same time, a basic element of such a support is the design of the roof-bolt and joists that are packed in the zone of active compression, but not just outside the area of rocks deformation [32]. The design and parameters of the separate elements of the self-regulating roof-bolt are represented in Fig.…”

Section: Methodsmentioning

confidence: 99%

Self-regulating roof-bolting with the rock pressure energy use

et al. 2018

View full text Add to dashboard Cite

The perspective of discovery of zonal disintegration phenomenon of rocks around underground mine workings is analyzed. The methodological stages for research of this phenomenon are shown. The physics of zonal disintegration of rocks around underground mine workings is disclosed. There are described the possibilities of advanced entropy method and developed energy method that allow to investigate a phenomenon of zonal capsulation of underground mine workings. The sequence of research of this phenomenon parameters is presented. The order of choice of stable shape and resource-saving support in underground mine workings is substantiated, for the deep horizons of the Kryvorizkyi Iron-Ore Basin mines. The method of parameters calculation of self-regulating roof-bolting in underground mine workings is substantiated, which allows to use the rock pressure energy. The design of a self-regulating roof-bolting is developed, which allows applying metal, polymer and rope bolts. The economic efficiency of rock pressure energy usage is substantiated in case of support setting at great depths in underground mine workings.

show abstract

“…The contact interaction of drill string elements with the borehole wall is a key factor that determines the energy inten sity of the drilling process as they are rotated. In this direction, the questions of mathematical modeling of the statics and dy namics of the core systems with respect to the problems of elimination of drill string grips remain [13,14], as well as the processes of drilling fluid circulation [15]. The refinement and analysis of their mathematical models, taking into account the work of the cuttingchisel type with a resilient or inelastic me dium, are necessary to ensure its longterm and safe operation as a longstemmed mechanical system.…”

mentioning

confidence: 99%

“…Analytical dependencies (13)(14)(15)) make a mathematical model for the study of the parameters of longitudinal and tor sional vibrations of a twomass drilling tool with four degrees of freedom, armed with a cuttingtype bit. By applying these dependencies, known nonstationary oscillation processes can be analytically investigated and simulated at empty slots, as is known in [15].…”

mentioning

confidence: 99%

Mathematical model of oscillations of a drill tool with a drill bit of cutting-scraping type

Chudyk¹,

Raiter²,

Grydzhuk³

et al. 2020

Nauk. visn. nat. hirn. univ.

View full text Add to dashboard Cite

Purpose. Finding the cause and effect relationships between the parameters of nonstationary longitudinal and torsional vibra tions of a drilling tool and developing a mathematical model to study their properties.Methodology. The solution to this problem is based on one of the basic principles of analytical mechanics -the Lagrange principle. The equation of motion of the studied rod mechanical system with four degrees of freedom is made using the Lagrange equation of the second kind, which is one of the next stages of its dynamic analysis.findings. In the process of solving this problem on the basis of industrial data, the analysis of axial load functions, angular rota tion speed and torque of the drilling tool for their nonstationarity was carried out. The frequency of change in these nonstation ary drilling mode functions is set by rapid Fourier transform. originality. For the first time, analytical dependences were obtained to determine the forces of cutting and friction on the bit from the second derivatives of the independent generalized coordinates of the mechanical system over time, as well as the relation ship between the generalized accelerations of the translational and rotational motions of the bodies of the mechanical system.Practical value. The practical value of the work is the obtained equations of motion of the system, taking into account the re ceived frequency compositions of the mode parameters of drilling until their subsequent numerical solution. The results of this task will further facilitate the choice of optimal modes of dynamic loading of the drilling tool in order to improve its energy efficiency and reliability. Analysis of the frequency dependences of the change in nonstationary functions of the drilling mode parameters will allow evaluating the level of wear of the rock destruction tool, as well as to predict the durability of the drill string elements.

show abstract

Drilling fluid circulation rate influence on the contact temperature during borehole drilling

Cited by 11 publications

References 9 publications

Approximate analytical model of rock thermal cyclical disintegration under convective cooling

Approximate analytical model of rock thermal cyclical disintegration under convective cooling

Self-regulating roof-bolting with the rock pressure energy use

Mathematical model of oscillations of a drill tool with a drill bit of cutting-scraping type

Contact Info

Product

Resources

About