RU96124367A - TWO-WALL ISOLATED OPERATING PIPE COLUMN AND METHOD FOR INSTALLING IT - Google Patents

Claims (19)

1. A double-walled insulated production casing (46) of pipes intended for hanging on a support means (58) and containing an inner and an outer pipe string with a heat-insulating gap (30) between the inner and outer pipe columns, characterized in that it consists of a plurality of sections of the outer pipes mechanically connected together to form an outer pipe string (27) and a plurality of sections of inner pipes mechanically connected together to form an internal pipe string (21), the inner and outer pipe columns being separate and spaced apart from each other essentially along their entire length.  2. A double-walled insulated pipe string according to claim 1, characterized in that a removable seal (31) is located at the lower end of the outer pipe string to prevent liquid from entering the outer pipe string.  3. A double-walled insulated pipe string according to claim 1, or 2, characterized in that the insulating gap (30) is filled with gaseous or liquid medium or is evacuated.  4. Double-walled insulated pipe string according to any preceding paragraph 1-3, characterized in that the inner and outer pipe columns (21, 22) are mechanically connected together at the upper end of the production pipe string (46) or at both ends of this pipe string (46), those. only at its upper and lower ends.  5. A double-walled insulated pipe string according to any one of the preceding claims 1 to 4, characterized in that the internal and external pipes are adapted to withstand a pressure exceeding the hydrostatic pressure of the liquid inside or outside the insulated pipe string (46).  6. A double-walled insulated pipe string according to any preceding paragraph 1-5, characterized in that the inner pipe (21) is pre-stretched and the external pipe (22) is pre-compressed to prevent exceeding the permissible stress levels in the inner and outer pipes, respectively, caused by fluctuations in the internal and outside temperatures.  7. A double-walled insulated pipe string according to claim 6, characterized in that the inner and / or outer pipe strings (21, 22) are equipped with means (35) for compensating the temperature along the axial length.  8. A double-walled insulated pipe string according to any preceding paragraph 1-7, characterized in that an insulating spacing means (34) is located in the insulating gap to maintain concentricity between the inner and outer pipe columns (21, 22) to prevent contact between the inner and outer columns pipes.  9. A method of installing a two-strand insulated pipe string, characterized in that the first section of the outer pipe with sealing means (21) at its lower end is performed when it is used to prevent liquid from entering the outer pipe, the second section of the outer pipe is mechanically connected to the end of the first segment of the outer pipes remote from the sealing means (31) for forming the outer pipe string (22), suspend the outer pipe string (22) on the support means (58) to connect the first and second sections of the inner pipe to be connected To form the inner pipe string (21) inside the outer pipe string (22), the inner pipe string (21) is suspended on the support means (58), the first and second inner pipe sections being connected mechanically together, the inner pipe string (21) is placed on distance from the outer pipe string (22) to form a heat-insulating gap between the inner and outer pipe columns (21, 22), with the inner and outer columns (21, 22) being separated substantially along the entire length.  10. The method according to claim 9, characterized in that more than two sections of the inner and outer pipes are connected together, respectively.  11. The method according to p. 9 or 10, characterized in that the sealing means (31) is removed by increasing the pressure of the liquid in the sections of the inner pipe or by mechanical means.  12. The method according to claim 11, characterized in that to equalize the hydrostatic pressure outside the sealing means (31) in the borehole, the inner pipe string (21) is filled with liquid and then the sealing means (31) is deactivated.  13. The method according to any one of claims 9 to 12, characterized in that the inner and outer pipes are mechanically connected together at the upper or at both ends of the production string (46) of the pipes.  14. A method according to any one of claims 9 to 13, characterized in that the connection (24) between the respective outer and inner pipes is impervious to liquid.  15. A method according to any one of claims 9-14, characterized in that the lower adapter (71) at the lower end of the pipe string is connected to the outer pipe string (22), and the holder (70) is connected to the inner pipe string (21) to form seals with outer column (22).  16. The method according to any one of claims 9 to 15, characterized in that they form a seal (26) for the gap at the top of the column to create a vacuum in the gap (30).  17. The method according to any one of paragraphs. 9-16, characterized in that the double-walled insulated pipe string (46) is placed in the pipe casing (47), and the cross-sectional area between the double-walled insulated pipe string (46) and the casing pipe (47) is larger than the cross-sectional area of the cavity in the inner a column (21) of pipes.  18. The method according to any one of paragraphs.9-17, characterized in that the temperature in the gap at the lower end of the production string (46) of pipes is approximately equal to the temperature at the lower end of the inner string (21) of pipes when using it.  19. A method according to any one of claims 9-18, characterized in that the means (35) for compensating the temperature along the axial length are installed in the inner and / or outer pipe string (21, 22).