Construction method for conducting pipe interior under-pressure plugging on production pipe string

Abstract

The invention discloses a construction method for conducting pipe interior under-pressure plugging on a production pipe string. According to the construction method, through an under-pressure delivering wellhead protecting device, through the five steps of under-pressure delivering, packer setting, pumping injection construction, packer unsetting and under-pressure pulling-out in sequence, an oilpassing pipe packer is plugged on the inner wall of the preset position of the production pipe string to achieve under-pressure construction operation, and a corresponding matched device is matched with a delivery oil pipe under the effect of a dual-stage hydraulic propeller through a floatable locking mechanism and a fixed locking mechanism to achieve the situation that the oil passing pipe packer is delivered to the preset position in the production pipe string under the situation of a Christmas tree is under pressure, then through a setting/unsetting control device, setting of the oil passing pipe packer is achieved, and thus bi-directional limiting fixing is conducted on the whole delivering device to complete the delivery operation process of the whole under-pressure delivering device. According to the construction method, effective isolation of Christmas tree upper hangers can be achieved, ground construction pressure limitation during pumping injection is improved, reservoir pollution brought by well killing operation is reduced, and the situation that the good effect is achieved on oil field development is ensured.

Description

technical field [0001] The invention relates to the technical field of pressure-bearing operation of oilfield water injection wells, in particular to a construction method for sealing a production pipe string with pressure inside the pipe. Background technique [0002] In the process of oil and gas exploration and development, the production string needs to be plugged in the pipe under various conditions such as the production string of high-pressure oil and gas wells being pulled out of the well or dealing with complex downhole accidents. Because the formation pressure is too high, the fluid in the wellbore has high pressure. Using the method of blow-off and pressure relief will not only destroy the formation and reduce the formation energy, but also the pressure in the wellbore will not drop to zero in a short time, and the water injection effect in the early stage will also be in vain. Carrying out the operation may pollute and harm the formation, reduce the pore permeab...

AI Technical Summary

Problems solved by technology

However, once the steel wire breaks during the operation, it will cause a major downhole operation accident.

In addition, due to the elasticity of the cable itself and the high pressure in the well, it is easy to cause the tubing plug to be set midway, causing major accidents, and it is necessary to install a cable protector at the position where each section of

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