Ultrahigh-density water-base drilling fluid and preparation method thereof

Abstract

The invention discloses ultrahigh-density water-base drilling fluid and a preparation method thereof. The preparation method of the ultrahigh-density water-base drilling fluid comprises the following steps that: (1) conventional barite is adopted as an exclusive weight material, so the density of the ultrahigh-density water-base drilling fluid reaches 2.55 to 2.70g / cm<3>, and the ultrahigh-density water-base drilling fluid comprises the following ingredients: clean water, humic acid fluid loss additive RSTF, sulfonated bitumen lubricant DHD, sulfonated phenolic resin fluod loss additive SMP-1, ferrochrome special thinner, sodium hydroxide (NaOH) and composite electrolyte; (2) basic formula of ultrahigh-density water-base drilling fluid with the density of 2.55 to 2.70g / cm<3> is determined through experiment; and (3) by changing the addition quantity of one processing agent in the basic formula, the influence of different addition quantity on the ultrahigh-density water-base drilling fluid performance is researched, so a best addition quantity range of the processing agent is obtained, and an achievement formula is finally obtained.

Description

technical field [0001] The invention relates to a drilling fluid for exploration and drilling, in particular to an ultra-high-density water-based drilling fluid in petroleum exploration and development. Background technique [0002] In recent years, with the continuous expansion of exploration fields, the layout of deep wells, ultra-deep wells, special wells and complex wells will continue to increase. The conditions are becoming more and more complex, and the drilling depth is increasing. The solution to the high temperature and high pressure problems in deep well engineering depends on the improvement of the performance of the drilling fluid, and the original drilling fluid is difficult to meet the engineering needs. Ultra-high-density drilling fluid can maintain the pressure balance of the wellbore in a high-pressure environment. Therefore, the study of ultra-high-density water-based drilling fluid has great theoretical and practical significance. Due to the limitation o...

AI Technical Summary

Problems solved by technology

Due to the limitation of the type of weighting agent, generally only barite can be used for weighting. When the drilling fluid density exceeds 2.50g / cm 3 When the drilling fluid is used, the properties of the drilling fluid are prone to deterioration, especially the rheological properties are difficult to control, and various downhole complexities are prone to occur, which restricts the drilling work of abnormally high-pressure oil and gas wells. Therefore, it is necessary to conduct ultra-high-density water-based drilling Extended research on liquid rheology

[0003] As an ultra-high-density water-based drilling fluid, its solid phase content is high, and the maintenance of rheological stability is more difficult than that of ordinary density drilling fluids, mainly reflected in the fact that the contradiction between its rheological properties and water loss wall building is more difficult to coordinate

If the ultra-high-density water-based drilling fluid contains only a small amount of free water, its rheological properties will become better, but the water loss will increase, the well wall will become unstable, and the mud cake will become thicker; The water volume is reduced, the well wall is stable, the mud cake is thinner, but the rheology becomes worse

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