Water injection well descaling device and method

Abstract

The invention relates to a water injection well descaling device and method. According to the technical scheme, an annular cavity is formed by a container outer pipe and a container inner pipe, wherein powdery acid ammonium salt is contained in the annular cavity; a lower baffle ring is arranged at the bottom of the annular cavity; the upper side of the lower baffle ring is connected with a liquidoutlet piston through a closing spring; a plurality of pressure transmission capillary tubes are arranged in the annular cavity; a container gland is arranged at the top of the annular cavity; a liquid inlet channel is formed in the container gland; the upper portion of the liquid inlet channel communicates with a liquid outlet opening pipe of a center pipe; an opening piston is arranged in an inner cavity of the liquid inlet channel; and the upper portion of the opening piston is connected with a reset spring. The water injection well descaling device and method have the advantages that thepowdery solid acid ammonium salt is adopted, more substances can be contained under the same volume, the opening and releasing structure of a container is replaced, the scale prevention time is prolonged, the adverse effect on the well site environment due to the fact that the scale prevention and descaling device is collided and damaged is reduced, and potential safety hazards are eliminated.

Description

technical field [0001] The invention relates to a scale removal device and method for a water injection well, in particular to an acid salt scale removal device for a water injection well. Background technique [0002] In the process of oilfield development, water is injected into the reservoir through special water injection wells to maintain or restore the pressure of the reservoir, so that the reservoir has a strong driving force, so as to increase the production speed and recovery rate of the reservoir. However, at present, the liquid injected into the formation through water injection wells is generally oilfield reinjection water, which contains relatively high calcium ions and magnesium ions. With the injection of oilfield reinjection water, due to the increase in temperature and pressure, the temperature rises to 100 degrees, and gradually Calcium carbonate and magnesium carbonate are formed, and then deposited in the inner cavity of the water injection column and the...

AI Technical Summary

Problems solved by technology

However, the existing problems are: first, the entire water injection pipe is full of hydrogen ions, which is easy to oxidize and corrode the water injection pipe string; second, the acidification volume of water injection wells is increasing, and repeated acidification wells are increasing year by year, but the injection effect is getting worse and worse , the effective period of acidification is getting shorter and shorter

The third is that the formation fluids are all acidified, so that the oil produced in the later stage has a higher acid content, which will affect the refining equipment in the later stage and increase the cost of refining

Its disadvantages are: because the annular cavity is filled with hydrochloric acid liquid, which has strong acidity, it is suitable for water injection wells that need to quickly eliminate scale or other special requirements; but this invention will inevitably be bumped during ground operation and construction. , which in turn leads to liquid leakage of the device, because liquid hydrochloric acid is used, in this way, the leakage will cause corrosion to other tools and cause environmental pollution, or when the hydrogen chloride gas is filled, it will pollute the well site environment and cause greater security risks

In addition, under the same volume, the anti-scaling and descaling device of the invention has a small amount of liquid hydrochloric acid. In some special water injection wells, the amount may not be enough, which may make the anti-scaling and descaling The time is relatively short, which cannot meet the needs of long-term scale prevention and descaling; the third problem is that when liquid hydrochloric acid is injected, hydrochloric acid liquid or hydrogen chloride gas is injected into the annular cavity through the one-way valve at the injection end, and when it is released, the outlet design In the upper part, it is pushed from bottom to top by springs and pistons. The whole process requires a complex mechanical structure to complete, and its manufacturing cost is high, and its reliability cannot be guaranteed to be very stable.

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