Throttling-free multistage layered fracturing pipe column and multistage layered fracturing construction method

Abstract

The invention discloses a throttling-free multistage layered fracturing pipe column and a multistage fracturing construction method. The pipe column comprises a horn mouth, a plurality of throttling-free self-service deblocking packers, throttling-free sand blasting sliding sleeves, sand prevention hydraulic anchors and hydraulic safety joints which are sequentially connected through oil pipes from bottom to top. In each throttling-free sand blasting sliding sleeve, a plurality of sand blasting holes are formed in a sand blasting sliding sleeve body, a throttling-free inner sliding sleeve is fixed in each sand blasting sliding sleeve body through a plurality of shear pins and seals the sand blasting holes, and comprises an outer cylinder and an inner cylinder with the axial length smallerthan that of the outer cylinder, and the inner cylinder sleeves the inner side of the bottom end of the outer cylinder through a connecting part in a manner that a gap exists; and the inner diameter of the inner cylinder of each stage of throttling-free sand blasting sliding sleeve is gradually increased from bottom to top. According to the non-throttling multistage layered fracturing pipe column,the purpose of completing multistage layered fracturing and layer combining production solving by tripping in the pipe column once can be achieved, bottom-to-top step-by-step fracturing constructionis achieved, and the sand conveying efficiency and the fracturing construction safety can be remarkably improved through the corresponding fracturing construction method.

Description

technical field [0001] The invention relates to the technical field of oil and gas field fracturing operations, in particular to an unthrottled multi-stage layered fracturing pipe string and a multi-stage layered fracturing construction method. Background technique [0002] In recent years, with the deepening of domestic oil and gas field development, the "K344 packer + sandblasting sliding sleeve" layered fracturing technology has become the main technology to improve the single well production of oil and gas fields. This technology uses the K344 packer to realize the interlayer isolation of the fracturing interval, and establishes the communication channel between the fracturing string and the reservoir through the choke bottom valve and the choke sandblasting sliding sleeve, which can realize the completion of running the fracturing string in one trip. The purpose of multi-stage layered fracturing and combined layers for production. [0003] However, in a large number of...

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Problems solved by technology

[0005] 2) The fracturing string needs to set the K344 packer through throttling of the throttle bottom valve and layer-by-layer throttling of the throttling sandblasting sliding sleeve, which not only limits the construction displacement, sand addition amount and construction scale, The wellhead pump pressure on the ground is also increased, which sacrifices the construction efficiency and cannot meet the needs of large-scale fracturing construction. At the same time, due to the throttling of the sandblasting hole of the throttling sandblasting sliding sleeve, the sand delivery efficiency is reduced and the fracturing is increased. The flow rate of the fluid through the sandblasting hole intensifies the wear of the sandblasting hole, and the backsplash produced by the high flow rate fracturing fluid will also cause serious erosion damage to the sandblasting hole and the production casing, which may cause the fracture of the fracturing string , Production casing deformation and other accidents bring great risks to subsequent wellbore operations;

[0006] 3) During the lowering of the fracturing string, the K344 packer is prone to unnecessary early setting due to pressure fluctuations in the well, resulting in the risk of frictional damage to the packer rubber sleeve;

[0007] 4) After the fracturing operation of the fracturing string, the K344 packer expansion rubber sleeve is automatically unsealed, but the structural characteristics of the rubber sleeve itself determine that the rubber sleeve cannot be completely recovered. In case of sand plugging, it will be unsealed. Incomplete sealing, sand stuck, resulting in difficulty or failure to pull out the pipe string

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