Water-based drilling fluid and preparation method thereof

Abstract

The invention discloses a water-based drilling fluid and a preparation method thereof. The water-based drilling fluid is prepared by mixing the following components in parts by weight: 100 parts of water, 0.25-0.35 part of sodium carbonate, 0.3-0.5 part of a flow modifier, 1-2 parts of a filtrate reducer, 1-2 parts of an inhibitor, 0.3-0.5 part of a coating agent, 6-8 parts of KCl, 1-2 parts of an aluminum compound blocking agent, 3-5 parts of a micro-nano blocking agent and a balanced amount of barite. Aiming at hard and brittle shale, the water-based drilling fluid has strong inhibition and plugging performances and is beneficial to reinforcing the wall of a well and reducing the generation of wellbore instability, chipping and collapse.

Description

technical field [0001] The invention relates to the field of petroleum drilling, in particular to a micro-nano strong plugging water-based drilling fluid and a preparation method thereof. Background technique [0002] With the expansion of the scope of exploration and development of petroleum resources, especially with the development of unconventional oil and gas resources such as tight oil and gas and shale gas, the wellbore instability of hard and brittle shale has become a key problem that needs to be solved urgently. For hard and brittle mud shale, through performance evaluation, it is found that the rolling recovery rate of this kind of cuttings in clear water is very high, generally greater than 50%, and the components basically do not contain or contain a small amount of montmorillonite, mainly illite mixed layer and illite Mainly, it will not be hydrated to make slurry, but it is easy to hydrate and disperse, causing blocks to fall or even collapse downhole. Past e...

AI Technical Summary

Problems solved by technology

For hard and brittle mud shale, through performance evaluation, it is found that the rolling recovery rate of this kind of cuttings in clear water is very high, generally greater than 50%, and the components basically do not contain or contain a small amount of montmorillonite, mainly illite mixed layer and illite Mainly, it will not be hydrated to make slurry, but it is easy to hydrate and disperse, resulting in downhole block falling or even collapse

Past experience shows that simply improving the inhibition of drilling fluid and increasing the dosage of conventional plugging agents, such as sulfonated asphalt, cannot effectively solve the problem of wellbore instability in hard and brittle shale

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