Downhole string cutting and fishing integrated tool and its construction method

Abstract

The invention relates to a downhole string cutting and fishing integrated tool and a construction method of the downhole string cutting and fishing integrated tool. The downhole string cutting and fishing integrated tool is suitable for downhole string fishing and particularly segmentation cutting and fishing operation of a sand screening pipe stuck by sand, the effect that cutting work and fishing work are completed by running a string once can be achieved, the construction time is shortened, the operation efficiency is improved, and the production cost is reduced. The tool comprises a cutting device and a fishing spear; the cutting device is provided with a cutting mechanism, a centralizing mechanism and a center rod, the cutting mechanism and the centralizing mechanism are installed on the center rod, and a fishing rod is arranged on the fishing spear. The cutting device and the fishing spear are connected through a positioning oil pipe, the center rod of the cutting device is provided with a setting releasing reversing track, and a setting mechanism is installed between the cutting mechanism and the centralizing mechanism and connected with the cutting mechanism through a slips. The fishing spear, the positioning oil pipe and the cutting device are connected to the bottom of the running string, the upper portion of the running string is connected with a ground driving device through a drill rod column or a common oil pipe, and then the running string is descended to a designed position.

Description

technical field [0001] The invention relates to a cutting and fishing tool for downhole pipe strings in the petroleum industry, in particular to an integrated cutting and fishing tool for downhole pipe strings and a construction method thereof, which is suitable for downhole pipe string fishing, especially segmental cutting and fishing operations for sand stuck sand filter pipes. Background technique [0002] With the deepening of oilfield development, the casing damage problem of horizontal wells, especially thermal recovery horizontal wells, has become increasingly prominent. Due to clogging, damage, deformation and other reasons, the sand filter tubes of some horizontal wells have caused sand control failure, and it is necessary to salvage and replace the sand filter tubes to start again. sand control. However, with long-term production, due to factors such as sand production in the formation, fluid erosion, and chemical corrosion, the sand filter pipe is seriously sand s...

AI Technical Summary

Problems solved by technology

However, with long-term production, due to factors such as sand production in the formation, fluid erosion, and chemical corrosion, the sand filter pipe is seriously sand stuck and the mechanical strength is reduced, making it difficult to control the salvage force during the salvage construction process, and the sand filter pipe is easy to pull out, increasing construction difficulty

If the downhole sand filter pipe is long, the success rate of one-time overall salvage is less than 20%

However, to complete one cutting and salvage, the next cutting pipe string and one salvage pipe string need to be lifted separately. To salvage all the sand filter pipes, multiple constructions need to be repeated, which greatly prolongs the construction time and increases the operating cost. Reduced work efficiency

[0004] To shorten the construction period and improve work efficiency, the most effective way is to adopt cutting and salvage integrated tools and techniques, while the existing cutting and fishing strings unable to meet this requirement

Because the inner cutter of the currently used cutting pipe string is a rotary seat seal type tubing inner cutter, the structure of this rotary seat seal type tubing inner cutter has the following defects: 1. When used in heavy oil wells, there is a lot of dead oil on the well wall , relying on the friction block of the righting mechanism to complete the rotary seat seal action is more difficult, time-consuming and laborious; 2. Once the cutter in the rotary seat seal oil pipe is seated, after the cutting operation is completed, the pipe string can be lifted up to unseal, but the slips And the righting mechanism is still in a free state, and the pipe string can only be lifted up, and the pipe string cannot be lowered. Obviously, this shortcoming cannot meet the requirements of the construction technology of the cutting and salvage integration process

The existing fishing spear also has technical defects: it can only be placed at the bottom of the fishing string for fishing, and the lower part of the fishing spear cannot be connected to other tools or strings

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