A fishing device and method for a sand-buried pipe string in an oil-water well

Abstract

The invention discloses a fishing device and method for an underground sand-buried pipe string in an oil-water well. The device includes a ground pressure pipeline and an underground fishing pipe string. The starting ends of the high-pressure pipeline and the second high-pressure pipeline are respectively connected to two branch ports of the same tee, the main inlet of the tee is connected to the pump truck, and the end of the first high-pressure pipeline is connected to the oil pipe joint at the upper port of the downhole fishing string, The end of the second high-pressure pipeline is connected to the casing joint of the wellhead. A pressure test cylinder and a valve are arranged between the first high-pressure pipeline and the tee, and a pressure gauge is installed on the pressure test cylinder. The invention solves the difficult problem of insufficient salvage force due to serious sand burial in the salvage operation.

Description

technical field [0001] The invention relates to downhole workover technology in oilfield development, in particular to a fishing device and method for downhole sand-buried pipe strings of oil and water wells. Background technique [0002] Oilfield development enters the middle and later stages, and the production strings of early oil and water wells gradually reach the end of their service life and enter the replacement period. Salvaging the original sand control strings and replacing them with new sand control strings occupies an increasing share of the current oilfield workover work. However, conventional fishing methods are limited by ground equipment in some wells and cannot provide large-tonnage lifting force. Especially in horizontal wells, due to the influence of the well trajectory, the lifting force is greatly reduced, and it is difficult to meet the needs of fishing operations. . [0003] The emergence of "Downhole Fishing Booster" (Patent No. 99243058.5) has alle...

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Problems solved by technology

[0002] Oilfield development enters the middle and later stages, and the production strings of early oil and water wells gradually reach the end of their service life and enter the replacement period. Salvaging the original sand control strings and replacing them with new sand control strings occupies an increasing share of the current oilfield workover work. However, conventional fishing methods are limited by ground equipment in some wells and cannot provide large-tonnage lifting force. Especially in horizontal wells, due to the influence of the well trajectory, the lifting force is greatly reduced, and it is difficult to meet the needs of fishing operations.

[0003] The emergence of "Downhole Fishing Booster" (Patent No. 99243058.5) has alleviated the problem of difficult fishing in horizontal wells to a large extent. Due to the reason of the anchor point, high pressure cannot be applied, and the pull-out force provided is limited, so some new technical methods appear, such as the patent "a sand-flushing salvage process for sand control strings" (application publication number CN102619486A) Cutting and sand washing are carried out through multiple pipe strings, and then salvage is carried out. Although this method adopts the method of segmentation and sand washing, the sand washing method is to circulate the sand from the production layer out of the wellbore, and then salvage the sand in the lower fishing pipe. It is not only time-consuming and labor-intensive to carry out fishing operations, but also often has a lot of poor timing. Especially for wells with serious sand production, it is often impossible to salvage because the sand is not produced quickly due to sand washing.

[0004] Therefore, there is still a big gap between the various existing fishing techniques and the actual needs of the site, and the period and cost of workover cannot be accurately predicted and controlled

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