An extended casing device for horizontal coalbed methane wells

Abstract

The invention relates to a casing extension device for a horizontal coalbed methane well, comprising: casing extension equipment connected in a casing string, the casing extension equipment is provided with an internal attachment, and the internal attachment has an opening When the casing string is extending downward, the internal accessories are in the closed state, which can restrict the fluid from passing through the internal accessories, so that the casing string under the extended casing equipment forms a horizontal air section, and the level of the casing string The air section is set in an airtight state filled with air, and a fluid with variable pressure is provided in the casing string extending above the casing equipment to form a vertical weighting section. The invention can not only solve the problem of difficulty in running long casings in the existing horizontal well section of coalbed methane, but also realize the cementing operation of the vertical section wellbore according to the construction requirements, and use special fishing tools to fish out the internal accessories after the well cementing is completed; The device divides the casing string into two sections: the horizontal air section casing and the vertical weight section casing.

Description

technical field [0001] The invention relates to a casing extension device for a horizontal coal bed gas well. Background technique [0002] With the continuous development of drilling technology, long horizontal section drilling has become the trend of oilfield development in the future, but long horizontal sections will inevitably affect casing running and well completion operations. The successful running of the pipe is the prerequisite for the smooth implementation of subsequent well completion operations. In recent years, the country has paid more and more attention to the development of coalbed methane resources. In order to improve the efficiency of coalbed methane mining, the horizontal section of coalbed drilling is also getting longer and longer. Due to the particularity of the buried depth of coalbed resources, the length of the vertical section of drilling is limited. Often the water-slip ratio of the wellbore is greater than 2, which puts great demands on the sm...

AI Technical Summary

Problems solved by technology

[0005] The invention provides a casing extension device for horizontal wells of coalbed methane, which has a reasonable structural design, can not only solve the problem of difficulty in running long casings in the existing horizontal wells of coalbed methane, but also realize the wellbore of the vertical section according to the construction requirements. After the cementing operation is completed, use a special fishing tool to fish out the internal accessories; use this device to divide the casing string into two sections: the horizontal air section casing and the vertical weight section casing

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