Wellhead safety operation method based on axial oblique-injection and suction drainage assistance

Abstract

The invention provides a wellhead safety operation method based on axial oblique-injection and suction drainage assistance. The operation method adopts a wellhead safety operation system based on theaxial oblique-injection and suction drainage assistance to realize the suction effect on combustible gas at a wellhead; the system includes a sand discharge pipeline, an axial oblique-injection and suction drainage assistance mechanism connecting the wellhead and the sand discharge pipeline, an ignition device, a gas injection unit and a first gas injection manifold; the first gas injection manifold provides inert gas produced by the gas injection unit to the inclined injection suction and drainage mechanism to form the negative pressure suction effect; and the ignition device is arranged at the outlet end of the sand discharge pipeline and ignites combustible gas discharged from the sand discharge pipeline. According to the operation method, a nitrogen injection suction method with doublechannel suction and adjustable gas injection can be realized, the safety risk of natural gas overflowing from the wellhead when "tripping operation and rubber core replacing" and other open well operation are carried out under the condition that a small amount of natural gas is produced from a formation is reduced, the safety of field operation is significantly improved, the operation method facilitates the development of gas drilling speed-up advantages, and is applicable to the field of reverse circulation drilling.

Description

technical field [0001] The invention relates to the field of drilling (drilling) engineering technology, in particular to a safe operation method for sucking combustible gas at the wellhead by using an inert gas (for example, nitrogen), which can be used in the technical field of oil and gas drilling, and is also suitable for reverse circulation drilling field. Background technique [0002] In general, gas drilling technology has the advantages of speed increase, leakage control and reservoir protection. In recent years, it has been widely used in Sichuan-Chongqing, Xinjiang, Qinghai and other oil and gas blocks, and the speed of conventional drilling has been increased by more than 3 times compared with the same period of last year. It is more and more common to use gas drilling to increase the drilling speed in gas-bearing intervals with poor drillability. Once a small amount of natural gas (≤10000m 3 / d), the circulating medium is converted to inert gas nitrogen to avoid...

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Problems solved by technology

There are many deficiencies in this treatment method: ①It is a passive control measure, which cannot fundamentally prevent the natural gas from overflowing the wellhead, but can only blow away the overflowed natural gas through the exhaust fan; , Wellhead operators still need to directly face the natural gas that may overflow, which has great potential safety hazards, especially when performing knocking operations; 3 / d), often forced to terminate gas drilling operations early, which is not conducive to the advantage of speed increase

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