Device and method for testing integrity of cement sheath under simulated prestress effect

Abstract

The invention discloses a device and a method for testing the integrity of a cement sheath under the action of simulating prestress. The device comprises a pressure-bearing chamber, an inner blind pipe, an annulus, an outer sleeve, a heating sleeve, a first screw rod, a second screw rod, a first nut, a boosting bearing, a square rod, a stress sensor, a rubber gasket, a circular plate, a gasket, a second nut, a pressure control system, a first through hole, an annular groove, a circular groove, a second through hole, a first male thread, a second male thread, a third male thread and a cement sheath. By means of the device and method, the integrity of the cement sheath under the prestress effect under the real working condition can be simulated, the interface bonding strength of the cement sheath is tested, the quantitative relation between the prestress and the interface bonding strength of the cement sheath is established on the basis, and the protection effect of prestress well cementation on the integrity of the cement sheath can be verified according to the experimental result. The method is suitable for the technical field of petroleum and natural gas drilling engineering.

Description

technical field [0001] The patent relates to the technical field of oil and natural gas drilling and production engineering, in particular to a device and method for testing the integrity of cement sheath under the action of simulated prestress. Background technique [0002] China's heavy oil resources are widely distributed, accounting for about 25% to 30% of the total oil resources, while the resources of individual oil fields account for a higher proportion, and heavy oil production has become the most important part of its output. Domestic and foreign oilfields generally use steam huff and puff and steam flooding technologies in heavy oil production. The steam huff and puff technology is to inject high temperature and high pressure steam (generally 300 ℃ ~ 360 ℃, 10MPa ~ 15MPa) into the well, heat preservation and pressure for a certain period of time (called "simmering well"), and then the heavy oil is thinned and then recovered. Compared with the conventional thin oil...

AI Technical Summary

Problems solved by technology

However, the mechanism and law of the influence of prestress on the integrity of the cement sheath, especially the shear bond strength of the cement sheath interface, are still unclear. Difficult to test the strength; 2) Lack of devices and methods that can truly simulate the integrity of the cement sheath under the action of prestress

[0004] For this reason, the present invention aims at the technical problem that it is difficult to accurately analyze the influence of prestress on the integrity of the cement sheath at present, and proposes a cement sheath integrity test device and method under simulated prestress, which can accurately obtain the cement under real working conditions. The shear bond strength of the cement sheath interface under different prestress, and based on this quantification of the relationship between the prestress and the cement sheath interface shear bond strength, and then verify the protective effect of the prestress on the integrity of the cement sheath. Provide a theoretical basis for the mechanical properties of the cementing interface of oil and gas wells, the integrity of the cement sheath and the optimal design of cementing

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