Separate-layer fracturing sand control string for thermal production well and sand control method thereof

Abstract

The invention discloses a separate-layer fracturing sand control string for a thermal production well and a sand control method thereof, and belongs to the technical field of the sand control in oilfield development. The string comprises two layers of strings of a sand control outer pipe and a process inner pipe, wherein the sand control outer pipe comprises a top packer, a backwashing device, a fracturing sealing tool, a fracturing filling outer tool, a one-way sealing tool, a screen pipe, an outer locating device, an interlayer packer and a pipe plug; the process inner pipe comprises a releasing tool, a fracturing filling device, a sliding sleeve switch, a locating tool and a fracturing filling conversion device. The sand control method comprises the following sand control steps of setting the top packer; releasing; setting the interlayer packer; lowering the process inner pipe, and carrying out fracturing sand control filling construction on a lower perforation interval; opening a circulating passage, and carrying out circulating filling; backwashing a well; lifting the processing inner pipe, and carrying out fracturing filling construction and circulating filling construction on other perforation intervals. As tools such as the backwashing device and the fracturing filling conversion device are used, the separate-layer fracturing sand control string for the thermal production well and the sand control method thereof have the advantages of well backwashing without moving the string, fracturing without casing pressure, flow-back prevention and the like.

Description

technical field [0001] The invention relates to a layered fracturing sand control pipe string for oil exploitation and a process thereof, in particular to a layered fracturing sand control pipe string for a thermal recovery well and a sand control method thereof. Background technique [0002] Unconsolidated sandstone multi-thin-layer heavy oil reservoirs have the characteristics of thick oil, multiple layers, large interlayer span, strong heterogeneity, and low permeability. It is difficult to implement sand control technology, and the filling effect of high-pressure extrusion is not ideal. The general fracturing sand control technology currently used, that is, multiple oil layers are in the same pressure system and the next fracturing sand control is completed. Compared with high-pressure filling sand control, it has larger displacement, higher construction pressure and larger treatment radius. The effect of increasing oil is relatively better. However, the general impleme...

AI Technical Summary

Problems solved by technology

However, the general implementation of fracturing and sand control due to the large difference between layers leads to uneven reconstruction between layers, and even some small layers cannot be produced, which affects the effect of fracturing and sand control. Clogging is prone to pressure mutation phenomenon, which will lead to the failure of fracturing and sand control in severe cases, and the construction risk is high

[0003] Chinese patent, application date 2004.11.03, application number 200410036213.6, patent name "Layered Squeeze Packing Sand Control String" discloses a technology that can realize layered gravel packing, but the movable string will be backwashed after the construction of this technology is completed Well, there are potential safety hazards; the upper part of the pipe string needs to use hydraulic anchors to prevent the pipe string from moving due to excessive construction pressure; due to the lack of a filling port switch device, the formation sand and filling sand will be ejected during steam injection and production in thermal recovery wells. Affect oil well production and sand control validity period

[0004] Chinese patent, application date 2011.02.11, application number 201110038345.2, patent name "one-time multi-layer gravel packing method and tool"; another Chinese patent, application date 2012.12.12, application number 201210534469.4, patent name "one-time multi-layer gravel packing method" ", the above two patent applications actually disclose a technology, and the downhole tools involved in the construction string used in this technology are disclosed in detail in other patent documents applied by the applicant of the technology, such as the application No. 201210534298.5, patent name "a rotary positioning tool"; application number 201210534344.1, patent name "a bushing for gravel packing tools"; The literature discloses a sand control technology that can achieve layered gravel packing in a pipe string, but this technology has the following technical problems: First, after the filling displacement is completed, there will be a small amount of proppant left in the downhole tool. , backwashing is required, and if sand plugging occurs during the construction process, the well needs to be backwashed immediately. The backwashing step of this technology is to lift the service tool first and then reverse circulation to wash the well, so that it may occur when the service tool is lifted During the process of sand settling, the tool gets stuck due to sand settling, resulting in operation failure; second, when this technology squeezes and fills gravel into the formation, the casing valve needs to be closed. If the fracture pressure is high, it may cause casing damage; thirdly, during the reverse circulation flushing operation, it may cause filling gravel regurgitation, which will affect the filling effect.

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