Freeze-thaw damage experiment device and method for shale through temperature and pressure control of liquid nitrogen

Abstract

The invention relates to a freeze-thaw damage experiment device and method for shale through temperature and pressure control of liquid nitrogen. A self-pressurization liquid nitrogen container is connected with a temperature and pressure control device through a low-temperature resistant metal pipe; ultralow temperature liquid nitrogen is contained in the self-pressurization liquid nitrogen container; a high-pressure nitrogen gas bottle is connected with the upper ends of the temperature and pressure control device and a freeze-thaw damage device through a high-pressure gas pipe separately; high-pressure nitrogen is contained in the high-pressure nitrogen gas bottle; the lower part of the temperature and pressure control device is connected with the lower part of the freeze-thaw damage device through the low-temperature resistant metal pipe; and a shale core is arranged in the freeze-thaw damage device and is connected with a data collection system through a low-temperature strain gauge. The freeze-thaw damage experiment device and method have the beneficial effects that shake freeze-thaw damage experiment can be carried out at different temperatures and pressure liquid hydrogen action, the adjustable temperature range is large, the damage degradation condition after contact of a stratum rock and the liquid nitrogen can be really simulated, the experiment method is simple, the experiment error is small, and a scientific evidence and a theoretical basis are provided for development of a shale gas reservoir employing an ultralow temperature liquid fracturing technology.

Description

technical field [0001] The present invention relates to the field of petroleum engineering reservoir production stimulation and reconstruction, in particular to a liquid nitrogen controlled temperature controlled pressure freeze-thaw damage experiment device and method for shale, which is used for the fracturing scheme design of ultra-low temperature liquid nitrogen fracturing technology to exploit shale gas and post-construction reservoir productivity predictions. Background technique [0002] Energy crisis and environmental problems are the greatest threats to human development in the world today, and environmental problems are largely caused by the irrational structure of energy consumption. The coal-based resource stock determines my country's coal-based energy consumption structure. In my country's primary energy consumption structure, coal accounts for 69%, which is about 40% higher than the world average; while natural gas accounts for only 5%. , far below the world a...

AI Technical Summary

Problems solved by technology

Since 2005, although my country has successively made breakthroughs in shale gas exploration in marine and continental organic-rich shale in many regions and times such as the Paleozoic in the southern Sichuan Basin, the Mesozoic in the northern Sichuan Basin, and the Triassic in the Ordos Basin. However, a large number of field practices have shown that it is difficult to carry out large-scale volume fracturing of shale gas reservoirs in my country, the volume of reservoir stimulation is limited, and the output of single well is low, which makes the prospect of this industry worrying

At present, most of the research on rock freeze-thaw damage is carried out around the problem of engineering frozen soil in cold regions. The temperature is only tens of degrees, which is not suitable for the temperature gradient of hundreds of degrees of liquid nitrogen ultra-low temperature fluid.

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