Preparation method of polyamide inhibitor for drilling fluid

Abstract

The invention discloses a preparation method of a polyamide inhibitor for drilling fluid. The preparation method comprises the following steps: (a) feeding a substance A and a substance B into a reactor according to the molar ratio of (0.5 to 2):1, heating to 60 DEG C, and stirring for 30 minutes till the materials are completely melted and mixed uniformly; (b) under the condition of nitrogen-gasprotection, carrying out insulating reaction for 5-8 hours at the temperature of 150-180 DEG C, and separating out water; (c) after the reaction is ended, cooling reactants to below 30 DEG C and obtaining yellow or brown-yellow viscous liquid, namely a final product; the substance A is dimer acid, trimer acid or a mixture of the dimer acid and the trimer acid. The polyamide inhibitor prepared by adopting the method has the characteristics of high-temperature resistance, obvious inhibition effect and slight influence on the rheological property and the like, is applicable to various water-baseddrilling fluid systems, not only can prevent the problem of well-wall instability caused by hydrous dispersion and expansion of clay minerals of the water-sensitive formation, but also can stabilizethe rheological property of the drilling-fluid system effectively and avoid the property from being out of control.

Description

Technical field [0001] The invention relates to the technical field of inhibitors for drilling fluids, and specifically to a method for preparing polyamide inhibitors for drilling fluids. Background technique [0002] When water-sensitive formations such as mudstone and shale are drilled with water-based drilling fluids, the formation minerals are easily hydrated and swelled and dispersed, resulting in instability of the borehole wall and difficulty in controlling the rheology of the drilling fluid. Therefore, the inhibition of the drilling fluid system has become the key to drilling water-sensitive formations. At the same time, as the scope and number of shale gas wells currently being drilled continue to expand, the inhibition of the drilling fluid system has become an important factor for safe drilling on site. [0003] Commonly used water-based drilling fluid inhibitors are mainly potassium salts, ammonium salts and amine (ammonium) polymer inhibitors. Although they have certa...

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Problems solved by technology

[0005] However, due to the limited adsorption capacity of the conventional inhibitors represented by the above-mentioned patent documents, desorption often occurs at high temperatures, resulting in the loss of inhibition at high temperatures.

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