A negative pressure blockage removal device for acidification and acid discharge and blockage removal

Abstract

The invention discloses a negative-pressure blocking remover for acidification and acid discharge blocking removal. The negative-pressure blocking remover comprises an insertion sealing tube, a sealing sleeve, a diffusion tube, a separation assembly and an outer tube. The insertion sealing tube is inserted in the sealing sleeve, the sealing sleeve is connected with the lower diffusion tube by a nipple, the outer tube sleeves the outer side of a combination of the sealing sleeve and the diffusion tube which are connected with each other to form the combination, an annular space is formed between the outer tube and the combination, the separation assembly with a spray nozzle is connected to the lower portion of the diffusion tube and the lower portion of the outer tube, and the spray nozzle is communicated with an inner center hole of the diffusion tube and an inner center hole of the insertion sealing tube and is communicated with the annular space between the outer tube and the combination of the diffusion tube and the sealing sleeve. The negative-pressure blocking remover has the advantages that acid liquor in acidified retention strata can flow back, blocking substances such as free sand in immediate vicinity of wellbore can be treated, acidification and acid backflow can be implemented in a string construction procedure, accordingly, operation procedures can be reduced, and the cost can be saved; continuous and stable negative-pressure can be generated, so that the blocking substances, the free sand and the like in the immediate vicinity of the wellbore can be carried to the ground via power liquor.

Description

technical field [0001] The invention relates to a pipe string for oil development, in particular to a negative pressure block removal device for acidification and acid discharge and plug removal. Background technique [0002] Mature oilfields have entered the late stage of ultra-high water-cut development, and reservoir plugging has become an important factor restricting oilfield development. At present, the plugging removal and injection enhancement process has a short validity period, within 3 months on average, mainly due to insufficient displacement and flowback during the acidification process. [0003] At present, flowback methods such as gas mixing (foam) and suction have poor application effects due to high cost and difficulty in controlling surface displacement pressure, while conventional backwash wells can only treat the wellbore, and cannot reduce the acidification reaction in the near-well zone and the formation The liquid is carried to the ground, causing seco...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a negative pressure blockage removal device for acidification and acid discharge and blockage removal, so as to realize the flowback of the acid liquid retained in the formation after acidification, and the treatment of blockages such as free sand in the near-wellbore area. The construction of the pipe string can realize acidification and acid flowback, which reduces the operating procedures and saves costs. At the same time, through the continuous and stable negative pressure generated, the blockages and free sand near the wellbore can be carried to the ground through the power fluid to solve the problem. At present, formation acid cannot be replaced after acidification, which leads to the problem of secondary pollution. By treating the area near the wellbore, the seepage channel can be unblocked, the validity period of acidification can be improved, and the operation cycle of oil and water wells can be extended.

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