Centrealoil

--Acidification temporary blocking technology

At present, for the sandstone reservoir exploitation and water injection well stimulation, acidizing plugging removal measures have achieved obvious effect of increasing production and injection. But for the multilayered oil-gas reservoir and large thickness reservoir acidification, the process is very important to select. For the different damage degree of multi-layer reservoir, because of injectivity disparity, if only a general acidification, it is not only unable to break down for serious damage reservoir, but also it will increase the difference of longitudinal permeability. This is mainly because that acid liquid first come into the highest permeability and minimum damage zone in the process of acidification. But for the need to be broken down low permeability or serious damage layer may be brought into little acid or no acid, even in the same layer cannot achieve the purpose of distribute acid uniformly. In this case, the shunt technology must be considered. Moreover, for the different damage degree of multi-layer and single layer thinner reservoir, using mechanical layering acidification is not only time-consuming, laborious and cost is larger, but also there is a hidden underground construction. At the same time, because of large amount of the conventional acid fluid filter loss and short the effective distance of acidizing, therefore, it can only make plugging in reservoir area near the wellbore.

Using temporary plugging acidizing technology, it can not only avoid the shortcomings of separate-acidification, at the same time, but also can effectively solve the thick vertical heterogeneity and the problem of acidizing plugging removal for the different plugging degree of the layers of multilayer reservoir. It is beneficial to restore and improve the longitudinal oil entry profile or injection profile, and is an effective, simple and convenient acidizing technology.

The core of the temporary plugging acidizing technology is liquid temporary plugging agent, the temporary plugging agent is water soluble colorless transparent liquid, a kind of milky white uniform suspension is formed when contacting with the acid liquid. Particle size of temporary plugging particles are evenly distributed in the acid solution, they will become the bridge particles in high permeability throat during the construction process. with the increase of temporary plugging agent continuously, high permeability reservoirs will be gradually closed, forcing the main acid in low permeability reservoir or polluted zone, then achieve the goal of separate layer acidizing. The temporary plugging agent in a certain period of time when oil can be dissolved completely, does not damage the reservoir, at the same time, reduce the water content after measures. The application of this technology in oil wells is more than 10 wells, and is more than 20 wells in water wells, and has obvious yield-increasing and augmented injection effect.

Characteristics:

①The temporary plugging acidizing technology not only can effectively remove the block of thick layer and                 vertical heterogeneity, but also can restore and improve the oil entry profile, it is more simple and easy                   compared with mechanical separate layer acidizing.

②The technology can alleviate the contradiction between the injection wells, improve the injection profile and               water flooding thickness.

③Construction is convenient, cost is low

④The temporary plugging agent  when oil can be dissolved completely, does not damage the reservoir, at the             same time, reduce the water content after measures.

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