A multi-functional packer that can be repeatedly set at low pressure after the first high-pressure setting

Abstract

The invention relates to a multifunctional packer capable of resealing under lower pressure after sealing under high pressure for the first time. The multifunctional packer is formed by an upper joint, a central pipe and a lower joint which are in threaded connection; the multifunctional packer adopts a scheme of sealing under the high pressure for the first time and resealing under the lower pressure in a normal working process, so that an expandable packer can be used together with a hydraulic slip pipe column anchoring tool and an inserting pipe connector, thus the danger to a lower packer rubber cylinder caused due to wriggle of an upper pipe column when pressure and temperature fluctuate is avoided fundamentally; the packer has functions of resisting impacting, resisting sealing in the midway, resealing under the lower pressure after sealing with high pressure for the first time, not unlocking an oil pipe during releasing pressure, washing well through large channels, effectively sealing segment length and lifting for unlocking; the packer is capable of effectively packing layers of casing pipe deformation wells, casing pipe corrosion wells, casing pipe damage wells, uncased wells and in particular carbonate shale oil storage ultra-deep uncased wells; and the packer is capable of carrying out excavating measures of injecting water in layers, finding water plugging, acidizing and cracking, injecting gas and reducing viscosity in the oilfield developing process.

Description

technical field [0001] The invention relates to a multifunctional packer which can be repeatedly set at low pressure after the first high-pressure setting, and belongs to the technical field of downhole tools in the oilfield development process. Background technique [0002] In order to effectively isolate casing deformed wells, casing corroded wells, casing damaged wells and open hole wells, especially between ultra-deep open hole wells in carbonate reservoirs, implement water plugging and acid fracturing , layered water injection, gas injection and dilution and other production stimulation measures require the packer to have the following functions: [0003] ⑴. It can avoid the phenomenon of midway setting, and it is safe to go down the well; [0004] (2) It can be used together with string anchoring tools and intubation connectors to overcome the damage to the rubber tube caused by the peristalsis of the string in ultra-deep wells; [0005] (3) The effective sealing sec...

AI Technical Summary

Problems solved by technology

[0010] Conventional compression packers have short rubber tubes and small well-washing passages, such as Y341 packers and Y241 packers, which cannot be tightly fitted in wells with deformed casings, corroded casings, damaged casings, and open holes Even if the wall is sealed, it cannot meet the requirements of large channel well flushing

[0011] There are two types of self-expanding packers: oil-swellable and water-swellable. This type of packer can expand automatically, and the construction process is simple. Because of its high expansion rate, it can realize squeeze packing without gaps, and is suitable for It is suitable for irregular wellbore and open hole, but the packer is a permanent isolation, and the pipe string cannot be pulled out normally, which brings hidden dangers to the subsequent repacking

[0012] Conventional K344 expansion packer is mainly composed of upper joint, central pipe, rubber tube and lower joint. The advantages of large and repeatable setting, but the disadvantage is that due to the low setting pressure, it is easy to set in the middle of going downhole; the second is that in ultra-deep wells, when the starting working pressure of the string anchoring tool is greater than the setting of K344 When the pressure is high, the K344 packer is set before the tubing string is anchored, and the peristalsis of the tubing string can easily damage the rubber casing. The deeper the well, the greater the temperature and pressure difference, the more obvious the damage; When the pressure is relieved and unsealed, a stable seal cannot be achieved.

[0013] A technician once installed a one-way valve at the water inlet of the K44 packer rubber cartridge, which can prevent unsealing when the oil pipe pressure is lower than the internal pressure of the rubber cartridge. However, it is precisely because of the function of the one-way valve that repeated sitting seal, also sacrificed the K341's large channel flushing function

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