Sea area natural gas hydrate horizontal well drilling fluid as well as preparation method and application thereof

Abstract

The invention provides a sea area natural gas hydrate horizontal well drilling fluid, which belongs to the technical field of drilling fluids in sea area natural gas hydrate resource exploration and development engineering, and comprises the following components: 90-110 parts of bentonite seawater slurry, 0.1-0.5 part of a low temperature flow pattern regulator, 0.5-2 part of a low temperature filtrate reducer, 1-3 parts of a hydrate kinetic inhibitor, 1-2 parts of a clay stabilizer and 1-3 parts of an extreme pressure lubricant, wherein the clay stabilizer is polyamine BDSC-200L; and the extreme pressure lubricant is a fatty acid derivative BDLU-400L. The drilling fluid has excellent low-temperature rheological property, clay expansion inhibition property, borehole cleaning property, lubrication drag reduction property and hydrate generation inhibition property. The invention further provides a preparation method and application of the sea area natural gas hydrate horizontal well drilling fluid.

Description

Technical field [0001] The present invention belongs to the technical field of drilling fluid in the seas and natural gas hydrate resource exploration and development project, which relates to a sea-free gas hydrate level well drilling fluid and preparation method thereof. Background technique [0002] The natural gas hydrate has the characteristics of high energy density, wide distribution, and great reserves, is known as the 21st century clean alternative energy source. The amount of natural gas hydrate resources in seabed sediments accounts for more than 90% of the total amount of natural gas hydrate resources, is the most developed area. In 2017, in 2017, in the South China Sea Fox, China successfully completed the sea, the natural gas hydrate was first tried, and the continuous gas production was 60 days. The cumulative gas production exceeded 300,000 cubic meters, creating the longest supply, gas production The largest two world records. [0003] Natural gas hydrated reserv...

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Problems solved by technology

[0003]The natural gas hydrate reservoir is thin, and horizontal well drilling can expose more reservoirs, which is beneficial to resource exploitation. However, due to shallow burial depth and poor diagenesis, compared with vertical well drilling , the hydrate horizontal well drilling fluid technology faces more and more difficult technical problems

Due to the shallow burial depth of the reservoir, the use of horizontal well drilling technology will inevitably lead to the well depth structure characteristics of shallow build-up point and large build-up rate, and the formation in deep water and shallow part has poor cementation, especially in highly deviated well sections and horizontal well sections. Wall stability is more difficult, wellbore cleaning is difficult, and the demand for lubrication and drag reduction is high

Compared with vertical wells, horizontal wells may enter a larger amount of free gas and reservoir decomposition gas, so the possibility of secondary hydrate formation is greater and more harmful

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