A two-stage seal bumper fishable completion device for horizontal wells

Abstract

The invention provides a two-stage sealing bumping-pressure salvageable well completion device for a horizontal well. The device comprises a drilling-free plug device, a bumping-pressure rubber plug and a salvaging device. The drilling-free plug device comprises a cementing switch and a packer. The upper end of the cementing switch is connected with a sleeve. The lower end of the cementing switch is connected with the upper end of the packer. The lower end of the packer is connected with a sieve tube. The cementing switch is a check valve type cementing switch. A check valve base is arranged at the bottom end of the check valve type cementing switch. The check valve base comprises a check valve and a blind plug. The two-stage sealing bumping-pressure salvageable well completion device is compact in structure, high in pressure bearing capacity, capable of ensuring the balance between the pressure of liquid inside a well completion pipe string and the pressure of liquid outside the well completion pipe string, convenient to operate on site and safe in construction.

Description

technical field [0001] The invention relates to a cementing tool for petroleum well completion, in particular to a two-stage seal bumper and fishable well completion device for a horizontal well. Background technique [0002] With the continuous deepening of oilfield development, measures to tap potential and increase efficiency are also further improved. In order to develop thin oil layers, there are more and more wells with special techniques such as horizontal wells and highly deviated wells, and various well completion methods have emerged as the times require. At present, in the horizontal well completion technology, in order to make the oil layer have a larger exposed area, avoid the damage of the cement slurry to the oil layer, and effectively protect the oil and gas layers, the precision sand filter tube completion method is often used. This completion method requires the staged cementing process of cementing at the top of the screen during the drilling process. Th...

AI Technical Summary

Problems solved by technology

The disadvantage of the step cementing device is that after cementing, it is necessary to run down the drill to remove the accessories (plugs, sliding sleeves and blind plates) of the step cementing device one by one, so as to get through the inner channel of the pipe string.

However, during the running of the pipe string, the pressure is often unstable; in this case, the control method of the internal and external pressure difference is likely to cause mis-sealing of the packer, and this mis-sealing cannot be observed at the wellhead, resulting in Continue to forcibly run in and cause damage to the packer;

[0007] (4) The open hole packer lacks shoulder outburst protection, poor adaptability to expanding boreholes during setting, and is prone to blast damage; at the same time, affected by factors such as wellhead pressure and liquid column pressure changes, During sealing and cementing, the overall pipe string is always in the state of axial creep, and it is easy to cause damage to the rubber sleeve and the formation due to abrasion;

[0008] (5) One end of the open hole packer is a movable head, which is because the movable head must move axially with the bulge of the rubber tube during seating; this structure meets the requirements for the sealing of the rubber tube, but the During the entry process, if the pipe string is blocked during the downward pressure process due to sand settling or collapse, it will cause the movable head to move upwards, resulting in radial expansion and wear of the rubber tube;

[0009] (6) Closing the rubber plug and blind plug is salvaged twice, which increases the string up and down once, which affects the working time;

[0010] (7) When the closing rubber plug is pressed, it is difficult to completely scrape off the cement residue on the casing wall, which makes it difficult or even impossible to salvage the salvaged fish head on the top of the closing rubber plug due to the deposition of the gray plug, thus requiring drilling operations. Complicated construction and affects work timeliness

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