Extending casing running device for coal bed methane horizontal well

Abstract

The invention relates to an extending casing running device for a coal bed methane horizontal well. The device comprises an extending casing running device body, the extending casing running device body is connected in a casing string, the extending casing running device body is provided with an internal accessory, and the internal accessory has two working states of opening and closing; when thecasing string extends downwards, the internal accessory is in the closed state so that fluid can be limited to pass through the internal accessory, the position, below the extending casing running device body, of the casing string forms a horizontal air section, and the horizontal air section of the casing string is in a closed state filled with air; and the position, above the extending casing running device body, of the casing string is internally provided with fluid with variable pressure so as to be a vertical weighting section. According to the device, the problem that in the prior art, long casing running for a coal bed methane horizontal well section is difficult can be solved, and meanwhile, the well cementing operation of a vertical section well bore can be realized according to the construction requirement, and after well cementing is completed, the internal accessory can be salvaged out through a special salvaging tool; and the device is used for dividing the casing string into two sections, namely the horizontal air section casing and the vertical weighting 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

Images