Underground corroding and sampling device and method

Abstract

The invention provides an underground corroding and sampling device and method. The device of the invention comprises a hollow tubular pile of which two ends are open, a sample suspending part which is arranged on the tubular pile and used to suspend a sample to be tested and a lifting beam which is used to drop the tubular pile in a well, wherein the underground corroding and sampling device is prepared from the material which can resist the corrosion of coal gas in the underground environment. The method of the invention comprises the following steps: using an asbestos rope or glass fibre rope to suspend the sample to be tested on the sample suspending part of the underground corroding and sampling device; using a lifting device, which is arranged at the wellhead section in a sealing mode for preventing the external leakage of the coal gas in the well, to drop the underground corroding and sampling device with the sample to be tested from the wellhead section into the producing well; standing the sample to be tested in the producing well to ensure that the the coal gas in the well fully contacts with the sample to be tested; and then using the lifting device to taking the underground corroding and sampling device out of the producing well to obtain the sample used for the analysis of corrosivity.

Description

technical field [0001] The invention relates to downhole corrosion sampling equipment and a method. Background technique [0002] In the process of underground coal gasification production in the field, the gasification environment of the underground coal seam is usually 100m~2000m away from the surface, the gasification pressure is 0.1MPa~2MPa, the gasification temperature is 200℃~1200℃, and the raw coal gas contains coal ash and tar , steam, H 2 , CO, CO 2 、CH 4 、H 2 S, Cl - , NH 3 and other components flow along the gasification channels and production wells. There are few reports on the evaluation of the impact of this environment on the corrosion of drilling casings, the corrosion resistance of different pipe materials in this environment, and the corrosion of underground gasification on casings. However, in actual production, it was indeed found that the drilling casing (especially the lower end) was corroded and perforated, and groundwater poured into the combu...

AI Technical Summary

Problems solved by technology

Since the operating temperature of the system is about 160°F (≈71°C), the materials used (non-metallic materials, glass reinforced plastic epoxy mentioned in the article) cannot withstand the harsh conditions of underground coal gasification. environment, especially the high temperature environment near 1000°C; the whole system is relatively complicated to manufacture, and the solid or closed structure has a great influence on the downhole airflow, so the system cannot be directly applied in the underground coal gasification environment

[0005] Invention patent US5627749 discloses a tool for remote and long-term corrosion environment monitoring in drilling. The monitoring tool uses a thin columnar resistance type corrosion sensor to measure the weight loss rate of downhole metal, and then investigates the corrosion situation under drilling. Its applicable temperature range It is relatively narrow and has a complex structure; in addition, the measurement of the metal weight loss rate in the downhole is seriously affected by the downhole fluid flow, so it is not suitable for use in underground coal gasification drilling

Once the coal seam is ignited, the high-temperature and high-pressure environment underground, the continuous flow of fluids, and the presence of corrosive / harmful gases make it difficult for any equipment to re-enter the drilling well

Images