Drilling-free hierarchical cementing method and cementing device

Abstract

The invention discloses a drilling-free hierarchical cementing method and a cementing device. The cementing device is composed of a full-bore pressure-difference hierarchical hoop, a rubber plug and a gravity hammer, the full-bore pressure-difference hierarchical hoop comprises a sleeve, an upper connecting hoop and a lower connecting hoop, the upper connecting hoop and the lower connecting hoop are connected at two ends of the sleeve, grouting holes and annular clamping grooves are formed in the inner wall of the sleeve from top to bottom respectively, a pressure difference sleeve sleeves positions of the grouting holes on the outer wall of the sleeve, a sealing sleeve capable of sliding up and down is arranged between the sleeve and the pressure difference sleeve, and the front end of the sealing sleeve seals and covers the grouting holes while the rear end of the same is in elastic contact with a spring. The rubber plug with a filler can expand along with changing of environment temperature; temperature of a well depth position at which the hierarchical hoop is located during well cementing operation is higher than 100 DEG C usually, so that a condition of triggering expansion of the rubber plug is more reliable, and well cementing effect of conventional well cementing rubber plugs is realized.

Description

technical field [0001] The invention relates to a drilling-free stepwise cementing method and a cementing device, which belong to the technical field of well cementing. Background technique [0002] Cementing is an important operation in the process of drilling and completion. With the gradual development of oilfields, the situation of underground formations becomes more and more complex. Under high pressure, formations become very easy to leak, which brings great difficulties and challenges to cementing operations. . There are still many deficiencies in the current conventional staged cementing process. Drill-free staged cementing is a cutting-edge cementing technology that can solve this problem. This process eliminates the drilling process after cement injection and shortens the project cycle. , reducing the construction cost, and at the same time, this technology prolongs the production life of the oil well, and has a significant effect on improving its comprehensive pr...

AI Technical Summary

Problems solved by technology

However, both of the above two methods have the following disadvantages: in the first method, electrical logging operations for well completion cannot be performed before the pipe string is passed through the well; in the second method, the rubber plug system (i.e. flexible plug , opening plug and closing plug) due to the soft material of the rubber plug, it is impossible to effectively clean the cement block on the inner wall of the casing, resulting in the rubber plug inside the staged cement injector not being able to fall freely to the bottom of the well in the later stage

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