Preparation method of nano blocking agent for oil field drilling fluid, blocking agent and oil field drilling fluid

Abstract

The invention provides a nano blocking agent for oil field drilling fluid and a preparation method and application of the nano blocking agent. The blocking agent is modified ketal formed by emulsifying ethyl acetoacetate propylene glycol ketal, water, span 80, propylene glycol monomethyl ether and ethyl acetate according to the weight ratio of 78-88: 10-15: 4.0-6.0: 3.0-5.0: 5.0-7.0. The blockingagent is simple in preparation method and can be obtained by adding all the raw materials and thoroughly and uniformly mixing, and is good in flowability and remarkable in effect of blocking stratum micro-cracks, particularly nano-scale micro-cracks, and can improve mud cakes, stabilize a well wall, prevent collapse and effectively solve the problems of instability, collapse and the like of the well wall after being added into drilling fluid of an oil field.

Description

technical field [0001] The invention relates to the technical field of oilfield drilling fluid materials, in particular to a nano-blocking agent modified ketal NAX50 for oilfield drilling fluid and the prepared oilfield drilling fluid. Background technique [0002] In the face of increasingly complex geological conditions in the process of oil and gas exploration and development, higher requirements are put forward for the stability of the well wall. The transfer effect in the micro-fractures causes the development of fractures, which makes the stability of the wellbore wall worse, and in severe cases, it leads to drilling accidents such as wellbore collapse. Therefore, it is necessary to add a plugging agent to the drilling fluid to improve the quality of the mud cake, plug the micro-fractures in the formation, and improve the stability of the wellbore. Formation micro-cracks often start from nano-scale pores, which develop and grow under the action of hydraulic pressure...

AI Technical Summary

Problems solved by technology

[0003] At present, most of the conventional plugging agents are modified asphalt, including sulfonated asphalt and emulsified asphalt. The particle size of these asphalt plugging agents is mostly in the micron level or above. plugging

When the initial nano-scale micro-fractures cannot be sealed in time, the growth of the micro-fractures will lead to the deterioration of the strength of the formation. Even if there are particles with matching sizes behind the plugging, the plugging effect is still very poor, and it cannot be effectively plugged and prevented from collapsing

[0004] CN111793478A discloses "a nano-sealing agent for water-based drilling fluid", which uses metal oxide magnetic nanoparticles with a particle size of 10-120 nanometers, but the deformability is poor, and it is difficult to enter micro-fractures

This is mainly because it is difficult to prepare inorganic and organic polymer particles smaller than 100nm, so the existing technology fails to solve the problem of plugging the initial cracks well

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