Preparation method and preparation device of foam drilling fluid for three-gas open-hole mining

Abstract

The invention relates to a preparation method and a preparation device of a foam drilling fluid for three-gas open-hole mining. The preparation method comprises the following steps: S1, preparing clear water, a foam stabilizer, a foaming agent and a stabilizer, wherein the foam stabilizer comprises carboxymethyl starch, carboxyethyl starch and carboxymethyl cellulose, the foaming agent includes sodium dodecyl benzene sulfonate, trimethyl ethyl lactone and stearyl alcohol, and a mass ratio of the carboxymethyl starch to the carboxyethyl starch to the carboxymethyl cellulose to the sodium dodecyl benzene sulfonate to the trimethyl ethyl lactone to the stearyl alcohol is (7-13):(7-13):(3-7):(3-5):(4-8):(0.5-2); S2, adding the clear water into a slurry preparing tank; S3, adding the foam stabilizer into the slurry preparing tank; and S4, adding the foaming agent and the stabilizer into the slurry preparing tank. The preparation method enables the density of the foam drilling fluid to be less than 1.00 g / cm<3> and adjustable, can meet requirements of various types of reservoirs, and effectively improves the system stability.

Description

technical field [0001] The invention relates to the technical field of drilling and production, in particular to a method and equipment for preparing foam drilling fluid for three-gas open-hole development. Background technique [0002] Three-gas open-hole mining refers to the mode in which three unconventional natural gas, such as sandstone gas, coalbed methane, and shale gas, are jointly produced in multiple layers, and the development is realized by means of open-hole well completion. At present, drilling fluids for unconventional gas development represented by tight sandstone gas, shale gas and coalbed methane are mainly polymer and inorganic salt drilling fluids, and the density can be adjusted, but it is always greater than 1.00g / cm 3 In the face of multiple types of reservoirs, excessive drilling fluid density is likely to cause leakage, and a large amount of drilling fluid entering the gas layer will damage the gas flow capacity of the formation, which is not worth t...

AI Technical Summary

Problems solved by technology

At present, drilling fluids for unconventional gas development represented by tight sandstone gas, shale gas and coalbed methane are mainly polymer and inorganic salt drilling fluids, and the density can be adjusted, but it is always greater than 1.00g / cm 3 , in the face of multiple types of reservoirs, the density of the drilling fluid is too high to easily cause leakage, and a large amount of drilling fluid entering the gas layer will damage the gas flow capacity of the formation, and the gain outweighs the gain

[0003] Drilling fluids represented by foam and recyclable microbubbles can achieve a density lower than 1.00g / cm 3 , but it is difficult to adjust the density. During the drilling process, different types of reservoirs require different density ranges, which cannot take into account the requirements of multiple types of reservoirs, and the stability of this type of system is poor, and the use effect is not good. In addition, in the prior art, On-site preparation of drilling fluid requires large-scale air pumps, high-pressure resistant mixing systems and high-pressure resistant pipelines, etc. The equipment is expensive and the process is complicated

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