A kind of ultra-low molecular weight intercalation inhibitor and preparation method thereof

Abstract

The invention relates to an ultralow-molecular weight intercalation inhibitor and a preparation method thereof. The ultralow-molecular weight intercalation inhibitor contains any one or more of amino triethylamine, ethylenediamine tetraethylammonium and diethylenetriamine pentaethylamine and is prepared from the component and clear water in a ratio of 0.5-3%; the amino triethylamine is synthesized from nitrilotriacetic acid; the ethylenediamine tetraethylammonium is synthesized from ethylenediamine tetraacetic acid; and the diethylenetriamine pentaethylamine is synthesized from diethylenetriamine pentaacetic acid; and the preparation method comprises the following steps: adding the raw materials into absolute ethyl alcohol; adding concentrated sulfuric acid for reacting; adding an organic solvent and introducing ammonia water; and stirring and distilling to obtain the product. According to the invention, the inhibition performance of a drilling fluid system can be remarkably improved, the temperature resistance exceeds 240 DEG C, the needs of ultra-deep well drilling are completely met, and the problem of unstable well wall caused by shale hydration and dispersion is effectively reduced; and moreover, the synthesis technology is simple and environment-friendly, the yield is relatively high, the production cost is low, and the ultralow-molecular weight intercalation inhibitor is suitable for industrial production.

Description

Technical field [0001] The invention belongs to the technical field of oil and gas field drilling, and specifically relates to a water-based drilling fluid inhibitor suitable for drilling the horizontal section of a shale gas horizontal well and a preparation method thereof. Background technique [0002] At present, in domestic and foreign drilling, there are often problems of borehole wall instability. Instability of the borehole wall may cause problems such as borehole collapse, diameter reduction, and sticking, which increases drilling time and drilling costs. 75% of wellbore instability mainly occurs in shale formations, especially water-sensitive formations. [0003] The exploration and development of shale gas resources in my country has been fully launched. In view of the characteristics of shale gas accumulation, horizontal wells have become the main drilling method for shale gas development. Compared with conventional horizontal wells, the horizontal section of shale hor...

AI Technical Summary

Problems solved by technology

60% to 70% of shale gas horizontal wells in foreign countries use oil-based drilling fluid system, and the vast majority of shale gas horizontal wells completed in China use oil-based drilling fluid system. Strong, good lubricity, and good for protecting the reservoir, but there are disadvantages such as not being environmentally friendly and relatively high cost

Water-based drilling fluids can just overcome the shortcomings of oil-based drilling fluids. However, there are still problems in the wellbore stability of water-based drilling fluids in mudstone or strongly water-sensitive shale formations at this stage, and in-depth research is needed.

[0004] At present, inorganic salts are mainly used as inhibitors in oil fields, but high concentrations of inorganic salts not only seriously affect the rheology of drilling fluids, but also cause serious pollution to the underground environment

Conventional shale inhibitors contain two primary amine groups or polyether amines, and alkyl primary amines are used as inhibitors, which seriously affect the rheology and wall-building properties of drilling fluids, and alkyl diamines are more toxic , does not meet environmental protection requirements

In order to increase its water solubility, polyamine shale inhibitors often add hydroxyl and ether bonds to the carbon chain, but this also reduces its inhibitory performance and has limited temperature resistance

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