Top well cementation method and device for self-communicated double-process screen pipe

Abstract

The invention discloses a top well cementation method and device for a self-communicated double-process screen pipe, and the top well cementation method and device are suitable for a top well cementation and completion process of a screen pipe of an oil-gas well. The method comprises the following steps: connecting an intermediate casing (1), a screen pipe (3), a casing (2), a self-communicated screen pipe top well cementation device (4), a screen pipe (5), an upper external packer (6), a lower external packer (7) and a pickling circulation valve (8) as designed; lowering to a well along with a casing string; circulating mud at an interval in the process of lowering the casing; throwing balls for keeping the pressure after putting in place to expand and seal a lower rubber barrel (4.5) and an upper rubber barrel (4.6) of a packer of the self-communicated screen pipe top well cementation device (4); keeping the pressure for opening the well cementation hole (4.12) of the self-communicated screen pipe top well cementation device (4); circularly performing well cementation; generating colliding pressure; continuing to keep the temperature; releasing the pressure; lowering a fishing spear to fish out a self-communicated inner pipe (4.0) of the self-communicated screen pipe top well cementation device (4); communicating the screen pipe (3) with the inside of the casing (1), so that the top well cementation and completion process of the screen pipe (3) is finished. According to the method, the mud can be circulated after the casing is lowered to the well, so that the risk of hole-wall collapsing and resistance meeting is lowered; the casing is communicated with the screen pipe after the colliding pressure is generated, so that the piston effect is removed and the success rate of fishing is increased.

Description

technical field [0001] The invention relates to a self-passing double-process screen pipe top cementing method and device, which are suitable for the screen pipe top cementing and well completion process of oil and gas wells. technical background [0002] The completion of the screen tube in the production layer of the oil well is beneficial to increase the production capacity. The top cementing realizes the sealing of the oil casing and the technical casing and improves the life of the string. The conventional method is to connect the top of the screen with a blind plate and an external packer for cement , The grading hoop used for outward circulation cementing. After the pipe string is lowered in place, the outer packer of the pipe is squeezed to expand and seal, and then the grading hoop is opened under pressure, and the inner casing of the grading hoop is drilled and removed after being pressed and solidified. Blind plate, so that the screen is connected with the upper c...

AI Technical Summary

Problems solved by technology

[0002] The completion of the screen tube in the production layer of the oil well is conducive to increasing productivity. The top cementing realizes the sealing of the oil casing and the technical casing and improves the life of the string. The conventional method is to connect the top of the screen to a blind plate and an external packer for cement. , The grading hoop used for outward circulation cementing. After the pipe string is lowered in place, the outer packer of the pipe is squeezed to expand and seal, and then the grading hoop is opened under pressure, and the inner casing of the grading hoop is drilled and removed after being pressed and solidified. Blind plate, so that the screen is connected with the upper casing, and the lower production tubing string is completed. Due to the need to drill the plug to complete the well, it is easy to cause damage to the tubing string at the grading hoop, burrs on the tubing wall, etc., which will bring risks to re-operation

In response to the above problems, the plug-free top cementing process has been developed in recent years. The blind plate, outer pipe packer and grading hoop are designed as a whole. The cementing process remains unchanged. Well, the disadvantages of the conventional technology have been eliminated, but the current technology and tools have the following problems: first, the mud cannot be circulated during the casing running process, and there is a risk of casing sticking and well wall collapse; second, the inner pipe is salvaged There is a piston pulling effect during installation, and the piston force increases by more than 20 tons for every kilometer of depth, which increases the risk of salvage. The application of this method in deep wells is limited

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