Chemical sealing rubber plug in snubbing operation string as well as preparation method and application of chemical sealing rubber plug

Abstract

The invention discloses a chemical sealing rubber plug in a snubbing operation string as well as a preparation method and application of the chemical sealing rubber plug. The chemical sealing rubber plug is prepared by uniformly dispersing 1-5wt% of acrylamide, 0.5-5wt% of vegetable gelatin, 0.01-0.2wt% of azo initiator, 0.1-0.5wt% of N', N-methylene bisacrylamide and 0.1-1wt% of montmorillonoid in water, and adding 0.2-1wt% of ammonium persulfate microcapsule. The ammonium persulfate microcapsule is added when pumping the chemical sealing rubber plug to an oil tube in a use process and after the process stops for 30-120min, thus obtaining the chemical sealing rubber plug in a snubbing operation string. Maximum compression strength of the cross-linked and solidified chemical sealing rubber plug liquor can reach 40MPa under well temperature of 50-120 DEG C, and automatic degradation and gel breaking can be realized after 2-7 days.

Description

technical field [0001] The invention relates to the field of oil and gas field development, in particular to a chemical plugging rubber plug in a pressure operation pipe string and its preparation method and application. Background technique [0002] Snubbing operation refers to the downhole operation technology that uses special workover equipment to implement pipe and rod tripping, wellbore repair and production stimulation measures under the condition of pressure at the wellhead of oil, gas, and water wells. Compared with conventional operation technology, snubbing operation technology has three advantages. One is to avoid damage to the oil and gas layers during the production process and better protect the original state of the formation; the other is to reduce the damage to the reservoir in the middle and later stages of development and better maintain the productivity of the formation; the third is to avoid the pressure relief problem of the water injection well operat...

AI Technical Summary

Problems solved by technology

The existing plugs have many structures and different effects, but there are defects such as "the insertion of the plug is limited by the perfection of the tubing string" and "the entire tubing string cannot be fully sealed"

The slip-type mechanical plug adopts an arc-shaped slip positioning device, which has a small contact area with the inner wall of the oil pipe, poor sealing effect, and inaccurate plug positions, and sometimes needs to deliver multiple or multiple plugs; the gravity-pressed rotary plug is adopted, When the diameter of the tubing string shrinks, it will cause the plug to be stuck in the middle and set in the middle; the structure of the small-diameter plug and the water-swellable plug determines that the outer diameter must be close to the inner diameter of the tubing to effectively seal, and cannot Through reducing and reducing tools (packers, water distributors, safety valves, etc.)

Therefore, when the pipe string has wax scale shrinkage, different diameter tools, irregular pipe wall corrosion, pipe wall damage, and downhole tool leakage and short circuit, the delivery plug will be blocked (cannot be delivered), delivery will not be in place, or The clogging effect is poor, which makes the clogging failure and the construction under pressure cannot be carried out.

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