Low-filtration-loss blockage relieving fluid for acidification oilfield well and preparation method thereof

Abstract

The invention discloses low-filtration-loss blockage relieving fluid for acidification oilfield well. The blockage relieving fluid is prepared from the following raw materials in parts by weight: 20-40 parts of organic acid, 110-130 parts of composite acid body, 2-4 parts of corrosion inhibitor, 30-40 parts of micellar acid stabilizer solution, 1-2 parts of surfactant and 1-3 parts of sodium tripolyphosphate. The reaction speed of the blockage relieving fluid with quartz and feldspar minerals is higher than that of the blockage relieving fluid with clay minerals, so that acid liquid not only can eliminate the formation pollution, but also can well improve the original permeability of the formation; the acid liquor system has good adaptability with the formation, and secondary precipitatedacid slag is not produced in a formation treatment process, so that new pollution is not caused.

Description

technical field [0001] The invention belongs to the field of plugging-removing fluids, and in particular relates to a plugging-removing fluid for low fluid loss acidification oil field wells and a preparation method thereof. Background technique [0002] Acidizing is one of the most effective production stimulation measures in the process of oilfield development and production. Its purpose is to remove acid-soluble blockages near the wellbore and in the pores of the oil layer, expand the circulation channels of the oil layer, and improve the permeability of the oil layer. However, due to the characteristics of rock structure and the existence of acid-sensitive minerals, if the choice of acid solution or process method is unreasonable, it will also cause damage to the formation, which is called acid-sensitive damage. [0003] The clay mineral assemblage in the oil layers of the Yanchang Formation is very simple, with chlorite as the absolute dominant, and the cement is mainly...

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Problems solved by technology

[0027] ⑤ The illite content in the Yanchang Formation oil layer is low, generally less than 5%, so the fluoboric acid system is not suitable for acidizing the oil layer;

[0028] ⑥The rocks in Yanchang oil layer have strong diagenesis, compact cementation, low porosity and permeability, high shale content in sandstone, and poor acid penetration ability in acidizing operations. Part of the acid solubility of acid fluid is consumed near the wellbore, making it difficult to remove blockages deep in the formation

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