High-broken-pressure stratum horizontal well sectional-fracturing method for well cementation and completion of casing

Abstract

The invention relates to a high-broken-pressure stratum horizontal well sectional-fracturing method for well cementation and completion of a casing. The high-broken-pressure stratum horizontal well section-fracturing method includes firstly perforating and fracturing all stratum layers by means of the hydraulic jetting fracturing technology for the horizontal well; then laying down a packer for fracturing a tubular pile sectionally and fracturing the stratum layers not fractured by the hydraulic jetting fracturing technology, wherein the maximum annular pressure of a well mouth is not higher than 45MPa during perforating and fracturing the tubular pile by hydraulic jetting. Hydraulic perforating and fracturing of the lower-broken-pressure stratum layers are integrated directly, construction requirements for high-broken-pressure stratum layers are met on the premise of keeping the requirements for mating of the well mouth and steel level of the casing without change or lower; for the high-broken-pressure stratum layers quite different in physical properties, hydraulic perforating is completed, and a basis is created for subsequent sectional fracturing by the packer. During sectional fracturing by the packer, the procedures of oil pipe transmission perforating and scraping can be omitted. The high-broken-pressure stratum horizontal well sectional-fracturing method for well cementation and completion of the casing has the advantages of flexibility in construction, simplicity to operate and high efficiency and safety.

Description

technical field [0001] The invention relates to a method for staged fracturing of horizontal wells suitable for casing cementing and well completion in low-permeability oil reservoirs, in particular to a staged fracturing method for horizontal wells with large differences in formation physical properties and high breaking pressure in some layers. split method. Background technique [0002] At present, the staged reconstruction of horizontal wells in China adopts two main technologies: hydraulic jet fracturing or packer staged fracturing. The hydraulic sandblasting and perforating staged fracturing process of horizontal wells uses the throttling effect of special tools to form a high-speed abrasive jet, which shoots through the casing, cement sheath and formation to form a certain depth of tunnel, and then presses the formation to perform fracturing. Construction; after one stage of construction is completed, lift the fracturing string, drag it to the next design position, a...

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Problems solved by technology

[0003] In contrast, the packer staged fracturing process is to use the tubing to transmit the perforation first, to construct all the construction intervals, then run the pipe string to scrape off the perforation burr, and finally run the double-sealed staged fracturing pipe string to block the first After the construction of the first perforation section, lift the pipe string and drag it to the second perforation section for construction; repeat the previous steps until the construction of all intervals is completed; the packer is pressed in sections The cracking process has relatively low requirements for wellhead matching and casing steel grades, but the downhole string structure is relatively complex, the safety performance is poor, and the construction process is relatively complicated, requiring tubing transmission and perforation, and a special scraper for shooting The perforation section is burr-treated, and there is a phenomenon that the formation cannot be opened due to imperfect perforation; in addition, the diameter of the perforation formed by the tubing transmission perforation is small, and there are disadvantages such as large perforation friction resistance, high formation breaking pressure and low oil production in the later stage

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