Results of the research of the working processes of shock thermomechanical impact on the soil during the pit diagnostics of pipelines

UDK: 622.692.4.07
DOI: 10.24887/0028-2448-2021-1-98-101
Key words: drilling, moisture content, gas pipeline, deformation, compressor, stress (tension, shear), shrinkage soil, cyclic air, power unit
Authors: B.L. Zhytomyrsky (Gubkin University, RF, Moscow)

The article deals with the results of research on the use of thermomechanical methods of soil development during drilling for diagnosing the technical condition and repair of pipelines in various climatic condition. The design and technical characteristics of a drilling rig with the use of a gas turbine unit as a source of heat and electric energy are given. The description of the mathematical model of the thermomechanical effect of heat flow on the soil is given. The model is based on classical laws and equations of continuum mechanics. The method of determining the effective stresses in the soil depending on pressure surges and flow surges is given. The analysis of influence of density of a heat flux at heat exchange and mass transfer, on thermodynamic and gasdynamic characteristics of process of influence of a heat flux on a ground is carried out. The results of the studies showed a significant difference between the calculated values of tensile stresses in the soil when the soil is heated from 10 to 200 °C from the values of stresses determined by mathematical models that do not take into account heat transfer and mass transfer. Thus, at phase transitions and mass transfer of moisture (with a change in moisture content from 40 to 10%), the calculated deformation (shrinkage) of the soil from the horizontal surface was 25 %. At the same time, shear stresses increased from 0.3 to 1.5 MPa, which, in the presence of a difference in the moisture content and temperature fields, is comparable to stresses. Experimental – industrial designs and scientific bases for creation of new generation of the thermomechanical drilling tool for well diagnostics and repair of pipelines with application of mobile gas-turbine engine as sources of thermal and electric energy are developed.

References

1. Zhitomirskiy B.L., The study of heat- and mass-transfer thermodynamics of the medium in soils during application of thermomechanical method of drilling duplets on main gas pipelines (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2019, no. 2 (110), pp. 38–43.

2. Zhitomirskiy B.L., Krokhmal' S.V., Razrabotka metodiki opredeleniya ratsional'nykh konstruktivnykh parametrov TMI (Development of a method for determining the rational design parameters of the insulation thickness gauge), Proceedings of Scientific and Technical Conference of 15th Central Research Testing Institute of Engineering Troops named after the Hero of the Soviet Union Lieutenant General of the Engineering Troops, Nakhabino, 2005, 57 p. 

3. Patent RU 2700756 C2. Method of ensuring energy efficiency of main gas transport, Inventors: Dubinskiy O.V., Dubinskiy V.G., Zhitomirskiy B.L., Lopatin A.S., Semchenkova O.V., Shotidi K.Kh.

4. Chuchkalov M.V., Dubinskiy V.G., Physical-mathematical model of "stress test" of the pipeline (In Russ.), Ekspozitsiya Neft' Gaz, 2013, no. 3 (28), pp. 87–95.

5. Zhitomirskiy B.L., Rezul'taty issledovaniya termodinamiki teplo i massoobmena sredy v gruntakh pri termomekhanicheskom sposobe bureniya shurfov na magistral'nykh gazoprovodakh (The results of the study of thermodynamics of heat and mass transfer of the medium in soils with the thermomechanical method of drilling pits on main gas pipelines), Proceedings of VIII International scientific and technical conference “Gazotransportnye sistemy: nastoyashchee i budushchee” (Gas transmission systems: present and future), 23–25 October 2019, Moscow: Publ. of Gazprom VNIIGAZ, 2019, 51 p. 

6. Galyas A.A., Fiziko-tekhnicheskie osnovy termomekhanicheskogo razrusheniya krepkikh gornykh porod (Physical and technical bases of thermomechanical destruction of strong rocks): thesis of doctor of technical science, Dnepropetrovsk, 1986.

The article deals with the results of research on the use of thermomechanical methods of soil development during drilling for diagnosing the technical condition and repair of pipelines in various climatic condition. The design and technical characteristics of a drilling rig with the use of a gas turbine unit as a source of heat and electric energy are given. The description of the mathematical model of the thermomechanical effect of heat flow on the soil is given. The model is based on classical laws and equations of continuum mechanics. The method of determining the effective stresses in the soil depending on pressure surges and flow surges is given. The analysis of influence of density of a heat flux at heat exchange and mass transfer, on thermodynamic and gasdynamic characteristics of process of influence of a heat flux on a ground is carried out. The results of the studies showed a significant difference between the calculated values of tensile stresses in the soil when the soil is heated from 10 to 200 °C from the values of stresses determined by mathematical models that do not take into account heat transfer and mass transfer. Thus, at phase transitions and mass transfer of moisture (with a change in moisture content from 40 to 10%), the calculated deformation (shrinkage) of the soil from the horizontal surface was 25 %. At the same time, shear stresses increased from 0.3 to 1.5 MPa, which, in the presence of a difference in the moisture content and temperature fields, is comparable to stresses. Experimental – industrial designs and scientific bases for creation of new generation of the thermomechanical drilling tool for well diagnostics and repair of pipelines with application of mobile gas-turbine engine as sources of thermal and electric energy are developed.

References

1. Zhitomirskiy B.L., The study of heat- and mass-transfer thermodynamics of the medium in soils during application of thermomechanical method of drilling duplets on main gas pipelines (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2019, no. 2 (110), pp. 38–43.

2. Zhitomirskiy B.L., Krokhmal' S.V., Razrabotka metodiki opredeleniya ratsional'nykh konstruktivnykh parametrov TMI (Development of a method for determining the rational design parameters of the insulation thickness gauge), Proceedings of Scientific and Technical Conference of 15th Central Research Testing Institute of Engineering Troops named after the Hero of the Soviet Union Lieutenant General of the Engineering Troops, Nakhabino, 2005, 57 p. 

3. Patent RU 2700756 C2. Method of ensuring energy efficiency of main gas transport, Inventors: Dubinskiy O.V., Dubinskiy V.G., Zhitomirskiy B.L., Lopatin A.S., Semchenkova O.V., Shotidi K.Kh.

4. Chuchkalov M.V., Dubinskiy V.G., Physical-mathematical model of "stress test" of the pipeline (In Russ.), Ekspozitsiya Neft' Gaz, 2013, no. 3 (28), pp. 87–95.

5. Zhitomirskiy B.L., Rezul'taty issledovaniya termodinamiki teplo i massoobmena sredy v gruntakh pri termomekhanicheskom sposobe bureniya shurfov na magistral'nykh gazoprovodakh (The results of the study of thermodynamics of heat and mass transfer of the medium in soils with the thermomechanical method of drilling pits on main gas pipelines), Proceedings of VIII International scientific and technical conference “Gazotransportnye sistemy: nastoyashchee i budushchee” (Gas transmission systems: present and future), 23–25 October 2019, Moscow: Publ. of Gazprom VNIIGAZ, 2019, 51 p. 

6. Galyas A.A., Fiziko-tekhnicheskie osnovy termomekhanicheskogo razrusheniya krepkikh gornykh porod (Physical and technical bases of thermomechanical destruction of strong rocks): thesis of doctor of technical science, Dnepropetrovsk, 1986.



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