Well bottom foaming foam drilling method

Abstract

The invention discloses a well bottom foaming foam drilling method. According to the method, a foam generator used for conventional foam drilling is placed at the bottom of a drill pipe, i.e., the top of a drill bit, so that foam can be generated at the well bottom, foam liquid pumped by a foam pump can enter an annular space formed between the inner wall of the double-wall drill pipe and the outer wall of the double-wall drill pipe through a double-passage air and water faucet to reach the foam generator arranged at the bottom of the drill pipe; compressed air enters an inner center passage of the double-wall drill pipe through the double-passage air and water faucet to reach the foam generator; foam liquid and compressed air are sufficiently mixed in the foam generator to generate foam; and the generated foam can carry rock fragments to return to the ground surface from the annular gap formed between the outer wall of the double-wall drill pipe and the well wall, so that the whole drilling flushing liquid circulation process is completed. The well bottom foaming foam drilling method provided by the invention has the advantages that the foam is generated at the well bottom; the breaking of the foam in the flowing process is prevented; the best quality of the foam at the well bottom is ensured; pure foam liquid and compressed air are injected into the well bottom; the flowing resistance is small; and the drilling cost is low.

Description

technical field [0001] The invention relates to a foam drilling method, in particular to a foam drilling method for foaming at the bottom of a well. Background technique [0002] Foam drilling technology is a new drilling technology used to deal with special self-heating geographical conditions and complex geological conditions. It uses a uniform and stable foam flow as the circulating medium for drilling. Due to its own characteristics, it overcomes the shortcomings of high-density drilling fluid, and also overcomes the shortcomings of atomized drilling and air drilling, and effectively solves the problem of desert drilling. Drilling technical problems in arid and water-scarce areas. At the same time, due to its low density, it has been widely used in fractured and fractured formations and low-pressure oil and gas layers; the upward return speed of foam is low. The scouring effect on the well wall is small, so it can effectively prevent accidents in the hole in the format...

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Problems solved by technology

At the same time, due to its low density, it has been widely used in fractured, fracture

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