High-temperature and high-pressure oil-gas well multifunctional fracturing completion pipe string and construction process

Abstract

The invention discloses a high-temperature and high-pressure oil-gas well multifunctional fracturing completion pipe string and a construction process thereof. The high-temperature and high-pressure oil-gas well multifunctional fracturing completion pipe string comprises an oil pipe, a packer, a closable fracturing sliding sleeve, a temporary plugging sand control screen pipe and a bottom mud displacement valve which are connected from top to bottom in sequence. High-pressure sealing safety joints are mounted on the part, below the packer, of the completion pipe string at intervals of a distance. The packer is internally provided with a shear pin. The closable fracturing sliding sleeve comprises an outer sleeve, an upper sliding sleeve and a lower sliding sleeve. The middle portion of theouter sleeve is transversely provided with a plurality of sand blasting holes. The upper sliding sleeve and the lower sliding sleeve are both of a cylindrical structure. The height of the upper sliding sleeve and the height of the lower sliding sleeve are greater than that of the sand blasting holes. The upper sliding sleeve and the lower sliding sleeve are arranged on the inner wall of the outersleeve and can slide along the inner wall to open and close the sand blasting holes. The temporary plugging sand control screen pipe comprises a base pipe. A pipe body of the base pipe is uniformly provided with a plurality of holes. Temporary plugging sand prevention filter parts are mounted in the holes of the base pipe. Through the high-temperature and high-pressure oil-gas well multifunctionalfracturing completion pipe string, a fracturing section can be opened and closed, and the problems of mud displacement, transformation and sand control completion of deep and super-deep high-pressureand superhigh-pressure oil-gas wells are solved better.

Description

technical field [0001] The invention relates to the technical field of well completion engineering, in particular to the technical field of fracturing completion pipe strings, in particular to a high-temperature and high-pressure oil and gas well multifunctional fracturing completion pipe string and a process. Background technique [0002] Due to the high formation pressure coefficient of deep and ultra-deep high-pressure (ultra-high pressure) oil and gas wells, in order to ensure the safety of well control in drilling engineering, it is necessary to use heavy mud to balance the formation pressure (some heavy mud density is as high as 2.5g / cm 3 above). The heavy mud system currently used in China has a very high solid content (as high as 60% in some wells), if the heavy mud in the wellbore cannot be fully replaced in the completion project, it will cause serious reservoir pollution and wellbore clogging, which seriously affect the production of oil and gas wells, and they h...

AI Technical Summary

Problems solved by technology

[0004] (1) The soluble screen adopts ordinary thread + packing sealing method, which has a low pressure bearing capacity and cannot meet the requirements of the well control problem in the process of lowering the soluble screen. Once the well control problem occurs, the string cannot achieve safe shut-in

Specifically: in the process of running the screen, if overflow occurs when the soluble screen or the drop-off short is at the wellhead position, after the blowout preventer is closed, the high-pressure oil and gas will break the hole plug from the inside of the soluble screen (due to bearing low pressure capacity), or puncture leakage from the missing short connection, causing out-of-control blowout accidents, which will lead to serious economic and social impacts

[0005] (2) The missing short connection has no sealing structure and is not sealed. There is a risk of completion fluid leaking from the missing short connection during the slurry replacement process, and the non-solid phase completion fluid "short circuit" circulates (cannot circulate from the bottom of the well), resulting in replacement The slurry effect is not ideal (the heavy slurry cannot be completely replaced without solid phase, and the wellbore cannot be cleaned)

[0006] (3) The lost-hand joint is only connected by soluble pins, and the connection strength is low. If the pipe string encounters resistance or jamming during the run-in process, complex accidents cannot be handled through the movable pipe string, and the pipe string has no ability to deal with resistance and jamming , high construction risk

[0007] (4) Since only soluble pins are used for connection, after the short joint is lowered into the wellbore, the soluble pins dissolve in the wellbore fluid medium, and the screens are independent of each other, which leads to the inability to carry out overall salvage in the later workover process , even if the pipe string is not buried in sand, multiple trips are required to salvage the screen pipe string, one section at a time, which leads to long construction period, high operating cost and low efficiency

[0008] (5) Dissolved short connection is connected by soluble pins. After the pins are corroded and dissolved, the lower pipe string will vibrate under the action of dynamic flow of production gas in the well, and the short connection will break off, resulting in multiple broken screens in the well. The pipe string, or even wrong connection, cannot guarantee the diameter of the pipe string, which is not conducive to oil and gas production and coiled tubing operations

[0009] (6) Soluble screens do not have the function of sand control and cannot meet the sand control needs of sand production wells

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