Dredging and scraping well washing device

Abstract

The invention discloses a dredging and scraping well washing device. The dredging and scraping well washing device comprises a central pipe and a pipe scraper, the outer wall of the central pipe is coaxially sleeved with the pipe scraper, and a water passing groove is formed in the peripheral side face of the pipe scraper. When the dredging and scraping well washing device is used, one end of the central pipe is connected with a tool string in series and then is put into a casing, cleaning liquid is injected into an annular space between the tool string and the casing, and the cleaning liquid returns into the central pipe from the open end of the central pipe and returns to the ground along the tool string through the water passing groove. According to the device, the outer wall of the portion, above the pipe scraper, of the central pipe is coaxially sleeved with a separation rubber plug, the separation rubber plug is in sliding sealing connection with the inner wall of the casing, and therefore the annular space between the central pipe and the casing is divided into an upper annular space section and a lower annular space section; in addition, the upper annular space section and the lower annular space section are in communication through a throttling channel; and the throttling channel has a throttling function, so that pressure difference is generated on the upper side face and the lower side face of the separation rubber plug, the dredging and scraping well washing device is pushed to advance in the casing through the pressure difference, and therefore the pipe scraper is assisted to advance in the underground horizontal section and the upwarp section, and full-pipe-section dredging and scraping well washing is achieved.

Description

technical field [0001] The invention relates to the technical field of underground oil and gas well construction, in particular to a scraping and cleaning device. Background technique [0002] Shale gas drilling mainly uses oil-based mud. After the casing cementing in the oil layer is completed, it is necessary to perform well drilling, scraping and well washing operations. The scraping and washing operations are relatively simple. The scraper and tool string are connected in series and then run into the well In the process, the scraper moves and scrapes the pipe wall dirt in the pipeline with the help of the gravity of the equipment itself and the thrust given to the tool string by the ground. The liquid, which passes through the scraper and back from the tool string to the surface, washes the dirt out of the pipe. However, at present, a large number of horizontal wells have appeared after drilling with geosteering technology, and even the horizontal sections of some wells...

AI Technical Summary

Problems solved by technology

However, at present, a large number of horizontal wells have appeared after drilling with geosteering technology, and even the horizontal sections of some wells have to be drilled along the updip direction of the formation.

For this kind of well scraper, it mainly relies on the thrust given by the ground to assist the scraper to move forward, and because the resistance in the horizontal section and the upturned section is relatively large, it is very difficult to lower it, and often occurs locking phenomenon in the horizontal section and the upturned section , It is difficult to scrape and wash the well through the whole pipe section

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