Paleozoic carbonate heat storage reservoir chemical fracturing well flushing technique

Abstract

The invention discloses a paleozoic carbonate heat storage reservoir chemical fracturing well flushing technique and belongs to the technique field of well flushing techniques. The paleozoic carbonate heat storage reservoir chemical fracturing well flushing technique comprises the steps that a self-made well flushing acid agent is combined with high-pressure well flushing, the well flushing acid agent is injected into the hole section needing acid well flushing treatment by means of a high-pressure pumper, and clear water is introduced till the well flushing acid agent stored in a drill rod is completely pressed into a well; an acid injection port and a blowout port are kept closed for 1.5-2.0 hours; and finally, the pressure is released, reaction residues are discharged, a well head device is dismounted, the drill rod is extracted, and a water pump is placed downwards into the well for pump flushing. According to the paleozoic carbonate heat storage reservoir chemical fracturing well flushing technique, the fracture rate of a heat storage reservoir is increased by means of high pressure, and meanwhile the fracture connectivity is made better by means of the chemical action of hydrochloric acid; and furthermore, a storage space and a run-off channel of underground hot water are improved, and the water yield of the geothermal well is increased.

Description

technical field [0001] The invention belongs to the technical field of well washing technology, and in particular relates to a chemical fracturing well washing technology for Paleozoic carbonate thermal reservoirs. Background technique [0002] The construction cost of geothermal wells is relatively high. Once the water production is not ideal, it will cause greater economic losses to investors. At present, the commonly used stimulation method is to inject concentrated hydrochloric acid into the well under normal pressure, and keep the concentrated hydrochloric acid in the well for a long time (generally more than 24 hours). 3 ) The chemical reaction increases the rock fracture rate to increase the water production of the well. This method has a certain effect on increasing water production, but it also has obvious shortcomings and deficiencies: [0003] 1) Under normal pressure, most of the hydrochloric acid stays near the well wall and cannot penetrate into the aquifer, ...

AI Technical Summary

Problems solved by technology

This method has a certain effect on increasing water production, but it also has obvious shortcomings and deficiencies:

[0003] 1) Under normal pressure, most of the hydrochloric acid stays near the well wall and cannot penetrate into the aquifer, that is, the well washing radius is small and the incremental effect is limited;

[0004] 2) If the concentration of hydrochloric acid is too high, it will not only corrode the equipment strongly, but also affect the water quality if the reaction of hydrochloric acid is not complete in the well;

[0005] 3) The hydrochloric acid stays in the well for a long time. Although the reaction time is prolonged, the various products produced by the reaction are not discharged in time, and deposits are likely to accumulate in the cracks, which will block the cracks again and affect the water production;

[0006] 4) There is no sealing device at the wellhead, which is likely to pose a threat to the safety of equipment, personnel and the surrounding environment during blowout