Device and method for monitoring temperature change in frozen soil layer drilling process

Abstract

The invention provides a device and method for monitoring the temperature change in a frozen soil layer drilling process. The device comprises a low-temperature constant-temperature test box, a double-layer circulation pipe, a drilling fluid circulation system and a temperature measuring system, wherein sandy soil/clay with a preset moisture content is laid inside the low-temperature constant-temperature test box, and is used for forming a frozen soil simulation layer; at least a part of the double-layer circulation pipe is positioned in the low-temperature constant-temperature test box; the drilling fluid circulation system is connected with the double-layer circulation pipe and is used for enabling drilling fluid with the preset temperature to circulate in the double-layer circulation pipe; and the temperature measuring system is arranged in the low-temperature constant-temperature test box and is used for monitoring the temperature change condition of the frozen soil layer in the low-temperature test box in the whole drilling circulation process. The method comprises the following steps of preparing the frozen soil simulation layer in the low-temperature constant-temperature test box; performing drilling fluid circulation in the frozen soil simulation layer through the double-layer circulation pipe; and dynamically monitoring the temperature of the frozen soil simulation layer. The device and method provided by the invention have the advantages that the frozen soil simulation layer is prepared in the low-temperature constant-temperature test box, and the temperature change condition of the frozen soil layer in the low-temperature test box in the whole drilling circulation process can be completely monitored.

Description

technical field [0001] The invention belongs to the petroleum drilling industry, and in particular relates to a monitoring device for temperature change during drilling in permafrost layers. Background technique [0002] Large areas of permafrost are widely distributed in the shallow strata of the arctic and sub-arctic low-temperature regions. The permafrost covers land and sea, with a thickness ranging from tens of meters to hundreds of meters. However, drilling in permafrost is very difficult. One of the important problems is that during the drilling process, due to the heat exchange between the drilling fluid and other circulating media and the formation and the cutting friction between the drill bit and the formation, the pore ice in the permafrost melts and freezes. The bearing capacity of the soil is greatly reduced. Some wells in West Siberia gas fields in Russia have subsided due to the melting of permafrost, and the maximum subsidence depth exceeds 3m. Therefore, m...

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Problems solved by technology

[0003] Domestic research on permafrost drilling is basically in a blank state. A device for simulating drilling in permafrost is disclosed in CN108104716A, which is mainly used to simulate the drilling process in permafrost, including drill bits, drill strings and ci...

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