A shale intercalation inhibitor made of ultra-low molecular weight branched tertiary amine polyamine

Abstract

A shale intercalation inhibitor made of ultra-low molecular weight branched tertiary amine polyamine, prepared by mixing ultra-low molecular weight branched tertiary amine polyamine and water in proportion, the ultra-low molecular weight branched tertiary Amine-type polyamines are prepared by stepwise synthesis or one-pot synthesis of polyamine compounds and tertiary amine compounds containing ethylenic bonds. Among them, the polyamine compounds are alkyl diamines, polyethylene polyamines and low molecular weight poly One of the amines. The ultra-low molecular weight branched tertiary amine polyamine provided by the invention is non-toxic and harmless, has a simple synthesis method, high yield, simple and easy-to-obtain raw materials, is suitable for large-scale industrial production, and is formulated as a shale intercalation inhibitor Compared with similar products, the suppression effect has been significantly improved, and it can effectively reduce the occurrence probability of wellbore instability due to shale hydration dispersion, fully meeting the drilling needs of various complex well conditions.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field drilling, and in particular relates to a shale intercalation inhibitor made of ultra-low molecular weight branched tertiary amine polyamine. Background technique [0002] Well wall instability often leads to downhole complex accidents such as well wall collapse, diameter shrinkage, and pipe sticking, which increases drilling time and drilling costs. 75% of wellbore instability mainly occurs in shale formations, especially water-sensitive formations. The content of clay minerals in shale formations is high, the horizontal section of shale gas horizontal wells is long, the contact time between drilling fluid and formation is long, shale hydration is more serious, and wellbore instability is more prominent. Although oil-based drilling fluid has obvious advantages in wellbore stability, lubrication and anti-sticking, inhibition of shale hydration expansion, formation slurrying and rapid dri...

AI Technical Summary

Problems solved by technology

The polyamine high-performance drilling fluid system is a new type of environmentally friendly drilling fluid that meets the various requirements of the drilling process and is considered to be a substitute for oil-based drilling fluid. Research at home and abroad shows that polyamine inhibitors with amine monomers as the main raw materials It has been widely used in water-based drilling fluid systems and has achieved good inhibitory effects, but most of the polyamine inhibitors studied and applied at present are linear structures

However, high-molecular-weight linear polyamine inhibitors are usually in the configuration of random coils after being dissolved in water, so that when they interact with shale clay, the entanglement and coating on the clay are uneven, which is likely to cause repeated adsorption or no adsorption

At the same time, the active groups generally exist at both ends of the molecular chain, so that a molecular chain usually only contains two active groups. In this case, the effect of linear polyamine inhibitors often has certain limitations.

And it is difficult for high molecular weight polyamine compounds to enter the clay layer, so that its inhibitory performance is limited

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