Rotary flow pickling method and device for removing contaminations in near-wellbore area of oil and gas well

Abstract

The invention relate to a rotary flow pickling method and device, wherein the device comprises a centralizer, a rotation controller and a spray gun which are connected in a sequential mode. The spray gun is rotatingly connected with the rotation controller and is a hollow column, the middle of the spray gun is a cylinder, the front portion and the rear portion of the spray gun are both formed into gradually diameter-contracted cones with plane sections, and the front end of the front cone with the plane section forms an inner taper hole; the sidewall of the middle of the spray gun is evenly provided with a plurality of lateral spray-holes which are arranged eccentrically, and fluids can enable the spray gun to rotate automatically; a backward spray-hole is formed on the rear portion of the spray gun and can generate backward-sprayed flow which can help suspend deposits of a shaft and mud cakes dropped from well walls, so that deposition can be avoided. The rotary pickling method for removing contaminations in a near-wellbore area of a oil and gas well can not only enhance radial impact effects of pickling solutions to the well walls, improve transfusion pressure differentials of the pickling solutions, add effective depth of the pickling solutions and improve the effects of the pickling solutions, but also can improve the cleaning and suspending effects of the pickling solution to the deposits inside the shaft, and increase the permeability of stratums near to the shaft..

Description

technical field [0001] The invention relates to the technical field of oil and gas field stimulation and reformation, in particular to a swirling flow pickling method and a pickling device for decontaminating near-well zones of oil and gas wells by combining swirling jet flow and common pickling technology. Background technique [0002] In the past 20 years, the application of horizontal wells in exploration, development and production has developed rapidly. Horizontal wells can increase the contact area between the wellbore and the oil layer, improve oil and gas production and ultimate recovery. However, because the working fluid of the horizontal well has been in contact with the reservoir for a long time and on a large area, its solid and liquid phases enter the formation around the well wall, and the pollution and damage suffered are relatively serious. This will inevitably cause damage to the formation and form a large-scale pollution zone. As a result, oil layers near...

AI Technical Summary

Problems solved by technology

[0003] In recent years, due to the continuous increase in the length of the horizontal section, the traditional general acid distribution technology not only consumes a large amount of acid solution, but also tends to concentrate and consume the acid solution in a certain well section, making it difficult to achieve uniform acid distribution in the entire horizontal well section

[0004] However, the general fixed-point pickling operation is adopted, that is, the fixed-point pickling of a certain well section is realized through the fixed downhole device at the end of the working string (usually coiled tubing). Although the fixed-point pickling operation of horizontal wells can be realized, the acid solution However, the reaction contact area between the acid fluid and the well wall is limited to a certain extent, and the tangential shearing effect of the acid jet impacting on the well wall is limited, which cannot form a strong shear on the drilling fluid mud cake. effect, affecting the release of drilling fluid mud cake, so the pickling effect is not very ideal

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