A true triaxial test device for ultra-deep drilling cores capable of simulating deep geological environments

Abstract

A true triaxial test device for ultra-deep drilling cores capable of simulating deep geological environments, including a rock sample support frame, a composite loading frame and a confining pressure sealing cover plate, the support frame is cylindrical and the rock sample is placed on the top, and the loading frame Set on the support frame through the central through hole, the support frame can be lifted vertically. When the support frame is lifted to the upper limit position, the top of the support frame is exposed. When the support frame is at the lower limit position, the cover is closed by the surrounding pressure, and the loading The frame and supporting frame are closed to form a confining pressure loading chamber, which saves the traditional pressure chamber, makes the structure of the test device more compact and the loss of frame stiffness is smaller, and meets the true triaxial loading requirements of small-sized ultra-deep drilling cores; The lower surface of the pressure-closed cover is provided with a heat exchange tube and a thermocouple. The heat exchange tube is connected to the high-temperature circulator outside the device. The thermocouple provides a temperature feedback signal for the high-temperature circulator. When the confining pressure loading chamber is filled with hydraulic oil, The hydraulic oil is heated through the heat exchange tube to simulate the deep temperature environment.

Description

technical field [0001] The invention belongs to the technical field of deep rock mechanics, in particular to an ultra-deep drilling core true triaxial test device capable of simulating deep geological environments. Background technique [0002] Internationally, wells with a drilling depth of more than 4,500 meters are generally defined as deep wells, and wells with a drilling depth of more than 6,000 meters are defined as ultra-deep wells. The temperature rises by about 3°C ​​per meter, and the vertical pressure of a 6,000-meter-level ultra-deep well can reach 162MPa, and the vertical pressure increases by about 2.7MPa when the drilling depth drops by 100 meters. When the drilling depth reaches 10,000 meters , the temperature at this depth can reach about 300°C, and the vertical pressure can reach about 270MPa. In 1984, the Kola ultra-deep drilling SG-3 drilling hole of the Soviet Union created a world ultra-deep well record of 12262m. In 1994, the German Continental Deep ...

AI Technical Summary

Problems solved by technology

[0003] With the rapid development of deep drilling technology, multidisciplinary scientific research has been carried out accordingly, among which the lithospheric deformation, deep mineralization conditions, structural geology and paleoclimate have been studied on deep drilling cores, but so far So far, it has not been carried out under the conditions of geological environment and underground real stress (σ 1 >σ 2 >σ 3 >0, σ 1 , σ 2 , σ 3 The experimental research on rock deformation and failure behavior of large principal stress, medium principal stress, and small principal stress) is mainly due to the lack of true triaxial testing machine technology for small-scale deep-drilling cores, and for deep-drilling cores. The related research of true triaxial mechanical test can be used for earthquake induction mechanism, rock rheological and shear characteristics in plate active zone, optimal direction selection for avoiding casing damage in deep oil and gas wells, brittle-ductile transition mechanism of deep rock and deep strata formation. Stress evolution history, etc. play a contributing role

[0004] The Chinese patent application number 201410055022.8 discloses a rigid follow-up loading frame structure, and the Chinese patent application number 201611187101.X discloses a high-pressure true triaxial hard rock constant temperature aging cracking test device and method, although from different levels It solves the simulation problem of true triaxial mechanical behavior of hard rock in deep engineering (deep mining and excavation of large deep tunnels), but it still cannot effectively meet the research needs of 6000-9000-meter ultra-deep drill cores in terms of temperature environment, and It is only suitable for deep engineering rock samples with a larger size of 50mm×50mm×100mm or 100mm×100mm×100mm. Due to the thinner diameter of the ultra-deep drilling core, it cannot be processed to the above size, and can only be processed into 25mm×25mm× For a small-sized rock sample of 50mm, if the test is carried out under the existing technology, the test can only be carried out forcibly by matching the size of the transition metal briquette. Fail, while also wasting valuable ultra-deep drill core

Images