Bushing non-uniform external pressure loading test device and bushing non-uniform external pressure loading test method

Abstract

The invention discloses a bushing non-uniform external pressure loading test device and a bushing non-uniform external pressure loading test method. The bushing non-uniform external pressure loading test device comprises, a rubber sleeve, an extruding cylinder, a mechanical plugging device, an external pressure loading system, an end clamping mechanism and a pressure detecting system, wherein the rubber sleeve is tubular rubber, a channel with the circular section is arranged at the axial centre, the rubber sleeve is sleeved outside a to-be-tested bushing, the periphery of the cross section of the rubber sleeve is a non-circular curved surface, an extruding cylinder is sleeved outside the rubber sleeve to form a pressure cavity for containing a high-pressure medium; the mechanical plugging device is hermetically arranged at two ends of the extruding cylinder, the centre of the mechanical plugging device is provided with a bushing hole through which a bushing is capable of passing; two ends of the rubber sleeve prop against the inner sides of the mechanical plugging device, and the space between the bushing hole of the mechanical plugging deice and the peripheral wall of the bushing is sealed; the external pressure loading system is communicated with the extruding cylinder and used for injecting the high-pressure medium into the extruding cylinder; the end clamping mechanism is used for clamping two ends of the bushing; the pressure detecting system is used for detecting the pressure on the outer wall of the bushing through a pressure sensor arranged on the outer wall of the bushing; the end clamping mechanism is fixed on a test frame. The combined loading pressure test for applying non-uniform external pressure is realized according to the device disclosed by the invention.

Description

technical field [0001] The invention relates to a casing external pressure loading test, in particular to a casing non-uniform external pressure loading test device and method. Background technique [0002] The collapse of oil casing under external pressure during service is one of the main failure modes. Many practices and studies have shown that the collapse and failure of a large number of casings is caused by non-uniform formation external pressure loads. Under the action of non-uniform external pressure, stress concentration occurs inside the casing, which is more likely to cause deformation or instability of the casing and loss of bearing capacity than when it is subjected to uniform external pressure. During the development and production of oil and gas wells, due to the creep effect of rock-salt layers, mudstone layers, etc., as well as other complex geological factors and engineering factors, the casing confining pressure is unevenly distributed. Especially for the...

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Problems solved by technology

Especially for the developing process of coalbed methane and shale gas, factors such as changes in ground stress due to long-distance horizontal well sections and repeated acidizing and fracturing processes have exacerbated the non-uniformity of casing external pressure effect

At present, most of the traditional casing

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