Salt-resistant drilling fluid with super-high density, preparation method and application thereof

Abstract

The invention discloses salt-resistant drilling fluid with super-high density, a preparation method and an application thereof. The drilling fluid comprises the following components in parts by weight: 450-750 parts of barite, 0.25-4 parts of bentonite, 2.5-20 parts of dispersing agent, 4-20 parts of filtrate reducer, 5-25 parts of sodium chloride, 1.25-7.5 parts of flow pattern regulator, 1.5-5 parts of pH value regulator, 2-8 parts of lubricant and 0.25-5 parts of surfactant. The preparation method comprises the following steps: adding the bentonite into water; ageing and then adding other components except the barite according to the dosage; stirring till the mixture is uniformly dissolved; and finally adding the barite, and stirring to prepare the salt-resistant drilling fluid. The density of the drilling fluid can reach 2.7-3.0 g / cm<3>, and the drilling fluid has excellent characteristics, such as good sedimentation stability and sedimentation stability, low water loss, easiness in regulation and control and the like, can be used for drilling construction of ultrahigh pressure stratums.

Description

technical field [0001] The invention relates to the field of petroleum drilling, and furthermore, relates to a salt-resistant ultra-high-density drilling fluid, a preparation method and an application. Background technique [0002] In recent years, deep well drilling technology has made great progress, and the complex formations such as high temperature, high pressure, salt rock and multi-pressure systems encountered by drilling are increasing, and the application range of high-density drilling fluid is becoming wider and wider. [0003] For ultra-high-density drilling fluid, the solid content is high, and the commonly used diluents have little or no effect on the weighting material, resulting in a rapid increase in drilling fluid viscosity, increased shear force, large internal friction, and poor shear dilution. When the colloidal property of the system changes, it often leads to the coalescence and precipitation of high-density solid phase particles, which makes it difficu...

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Problems solved by technology

[0006] Compared with foreign countries, there are relatively more researches and applications on high (or ultra-high) density drilling fluid technology in China. In order to ensure good rheological properties of drilling fluid, high-density and high-quality weighting materials are often selected, such as "high-density In the article “Research and Application of Drilling Fluid Technology” (Drilling Fluid and Completion Fluid 2009.7), the density of 2.9g / cm2 was prepared by using iron ore powder and barite composite weighting method. 3 The ultra-high density drilling fluid, the highest density of the actual field application is 2.55g / cm 3 , the large application of iron ore powder not only increases the cost of drilling fluid, but also increases the frictional torque due to the magnetic properties of iron ore powder;

[0007] In patent 200710049033.5, modified barite was used to prepare 2.5g / cm 3 The ultra-high-density drilling fluid is used in the 6130m section of Heba 1 well; "Research and application of ultra-high-density drilling fluid technology in deep wells in Chishui area" (Drilling and Production Technology 2006.3) reported a density of 3.0g / cm 3 Drilling fluid with a density greater than 4.3g / cm in order to reduce the total solid content of the system 3 Barite, this kind of high-density, high-quality barite has few ore sources, which is not conducive to popularization and application

Surface treatment of weighted materials can also affect their large area applications

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