In-situ exploitation flow-heat transfer experiment device for compact oil shale

Abstract

The invention relates to an in-situ exploitation flow-heat transfer experiment device for compact oil shale, and belongs to the technical field of experiment measuring instruments. The device comprises a flow-heat transfer core holding unit, an axial-confining pressure injection system, an axial-radial pressure stabilizing system, a temperature-strain monitoring system, a liquid cooling circulating system, a safety backflow preventing system, a flow monitoring system, a gas collection-recovery system and a control and data recording system cooperating with each other. According to the device,a thermal fluid medium with pressure is injected into a core with a fracture in the flow-heat transfer core holding unit, and axial and radial strains are observed to determine a critical temperaturepoint that the fracture in the core closes up under the condition of heat injection and critical pressure that the fracture is opened again under the pressurizing condition of the thermal fluid mediumin the later period, and thereby, closure critical parameters of the fracture during in-situ exploitation are obtained; and the permeability variation situation of the core with the rock mass fracture can be evaluated through the conditions of flow before changes and flow after changes, and thereby, reservoir fractures effectively communicate for a long term by regulating site construction parameters to facilitate heat injection and oil and gas migration in the later period.

Description

technical field [0001] The invention belongs to the technical field of experimental measuring instruments, in particular to a seepage-heat transfer experimental device for in-situ mining of tight oil shale. Background technique [0002] With the rapid development of the domestic economy, the energy consumption of oil and natural gas has increased significantly. At this stage, the dependence of domestic crude oil on foreign countries has increased year by year. In recent years, my country's dependence on foreign crude oil has exceeded 70%. At the same time, the exploitation of conventional energy resources such as coal, oil, and natural gas has gradually become weak. Considering the development needs of modern society, conventional energy supply has been unable to support the long-term sustainable development of industry. In recent years, unconventional energy resources such as oil shale, oil sands, coalbed methane and shale gas have huge reserves and broad prospects for exp...

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Problems solved by technology

[0004] In the process of underground in-situ mining, the internal fracture opening of oil shale is very small. During the heat injection process, due to the obvious thermal expansion and thermoplastic rheology of the rock formation, the proppant inside the fracture will be pressed into the formation to cause the fracture to close. At the same time, the kerogen The asphaltene formed by cracking enters the compacted fractures, leading to the complete closure of the diversion channels, which reduces the heat injection rate, and the heat injection mode changes from heat conduction-convection to complete heat conduction, which not only reduces the production efficiency but also makes the cracked oil and gas resources unable to transport. shift, resulting in lower injection-production efficiency and increased construction costs

[0005] At present, the experimental device for exploring unconventional reservoir seepage-heat transfer is mainly a fluid fracture seepage simulation device under high temperature stress, see CN107991216A for details. Rubber sleeve, it is difficult to realize the sealing of the device under high temperature and high pressure conditions; the high temperature and high pressure coal rock supercritical carbon dioxide fracturing-creep-seepage test device, see CN110057739A for details, it is also difficult to guarantee the experimental requirements by using rubber sleeves for sealing, and the device uses LVDT displacement detection system, the device is effective in measuring under the condition of medium and high temperature less than 200°C, and a high-temperature and high-pressure hydraulic fracturing holder and its test method, see CN109870349A for details, the internal compression spring is relatively large under high-temperature and high-pressure conditions Large deformation, it is difficult to ensure that the core is always in a compressed and sealed state, and it is difficult to realize the experiment

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