Method for multi-cluster fracturing in horizontal well and multi-cluster perforation fracturing string for implementing the method

Abstract

The invention discloses a horizontal well multi-cluster fracturing method and a multi-cluster perforating and fracturing pipe column for implementing the method. In a sand blasting and perforating phase, each perforating section in the same fracturing section is subjected to sand blasting and perforating according to the sequence from top to bottom; after the last time of sand blasting and perforating is finished, sand-carrying liquid in the multi-cluster perforating and fracturing pipe column is substituted to the position above a building up section of a shaft through fracturing base liquid but is not substituted from the shaft, so that when prepad fluid is filled into an annular space between the shaft and the multi-cluster perforating and fracturing pipe column, perforating sand in the sand-carrying liquid blocks a crack opened in the front perforating section to certain degree, and a crack is conveniently opened in a rear perforating section. The opening degrees of the cracks of cluster perforating sections in the same section are consistent, and the reliability and the construction efficiency of section-to-section multi-cluster fracturing are improved.

Description

technical field [0001] The invention relates to a method for multi-cluster fracturing of a horizontal well and a multi-cluster perforation fracturing string for implementing the method. Background technique [0002] At present, domestic horizontal well borehole staged fracturing technologies are mainly coiled tubing staged fracturing and drillable bridge plug staged fracturing. The coiled tubing staged fracturing process is a coiled tubing sandblasting perforation, annulus sand fracturing, which can realize large-scale fracturing. After the fracturing stage is completed, a section of sand plug is left in the wellbore as an isolation, and the pipe string is dragged to the next target section for fracturing. The disadvantages of this process are long construction period and difficulty in flushing the sand plug. The staged fracturing process of drillable bridge plug can realize multi-cluster fracturing, using hydraulic pump to send cables and bridge plug tools to the target la...

AI Technical Summary

Problems solved by technology

The disadvantage is that it uses a single spray gun, which is prone to incomplete perforation and the formation cannot be opened. The packer used is a hydraulic seated packer. After each stage of fracturing, the well must be backwashed before the coiled tubing can be lifted. , and it is easy to unblock when the coiled tubing displacement is low

In addition, after the perforation is completed, the sand-carrying fluid will be completely displaced from the wellbore. In this way, during the fracturing process, the fluid mainly enters from the fractures opened for the first time, which will be unfavorable for the fractures in the subsequent perforation section to open, resulting in fracturing. The fracture opening degree of each cluster perforation in the fracture section is different, which is not conducive to subsequent oil recovery operations

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