31 results about "Coal permeability" patented technology

The invention discloses a device for simultaneously measuring expansion and permeability rate of gas injected into a coal rock under a tri-axial stress condition. The device comprises a gas injection system (1), a confining pressure system (2), an axial pressure loading machine (25), a permeability measuring system (3) and a data acquisition system (4), wherein the gas outlet port of the gas injection system (1) is connected with the gas inlet port of the confining pressure system (2) through a high pressure gas inlet pipe (43); the axial pressure loading machine (25) is arranged at the external part of the confining pressure system (2); the permeability measuring system (3) is connected with the gas outlet port of the confining pressure system (2) through a high pressure gas pipe; and the data acquisition system (4) is connected with the confining pressure system (2) through a data line with a sensor. According to the device provided by the invention, the problem of measuring coal-body deformations and permeability variations of different adsorption gases at different temperatures and different pressures is effectively solved; in addition, the permeability and coal-body change laws caused by a gas injection displacement in the process of developing coal bed gases are effectively simulated so that the production practice is beneficial to be further guided.

The invention relates to a low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental method belonging to the field of low-permeability coal seam reinforcement anti-reflection technology. The low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental method adopts a low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental device, and comprises the following steps of: (1) installing a monitoring element; (2) measuring the coal permeability before anti-reflection; (3) starting a high-pressure gas impact system for impacting coal briquettes in a circulating way; and (4) measuring the coal permeability after anti-reflection; and the low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental device comprises a coal sample, a blasting cylinder mechanism, a triaxial loading system, a high pressure gas impact system and a coal permeability measurement system.

The invention discloses a coal permeability testing device and a use method thereof. The coal permeability testing device comprises a support, a clamper, a confining pressure pump, an axial pressure pump, a gas cylinder and a gas booster pump; the clamper is arranged in the support, and comprises a barrel, the upper end and the lower end of the barrel are respectively provided with a core plug in a penetrating manner, the core plugs are respectively provided with air vents along the axial direction, the side wall of the barrel is provided with a confining pressure interface which communicated with an inner cavity of the barrel, the confining pressure interface is connected with the confining pressure pump through a pipeline; an axial pressure cavity is arranged on the support above the clamper, the lower end of the axial pressure cavity is provided with a telescopic rod, the lower end of the telescopic rod is connected with the upper end of the core plug at the upper end of the barrel, the axial pressure cavity is connected with the axial pressure pump through an axial pressure pipeline; the air vent in the core plug at the upper end of the barrel is connected with a gas outlet end of the gas booster pump through a pipeline, a gas inlet end of the gas booster pump is connected with the gas cylinder. The coal permeability testing device is simple in structure, convenient in operation and accurate in test result, not only can be used for testing the coal permeability, but also can be used for testing the permeability and ultrasonic characteristics of other rock specimens.

The invention discloses a triaxial seepage device for changing the humidity of gas and positive pressure of an outlet end. The triaxial seepage device comprises a triaxial pressure system, wherein a gas supply system is connected with the air inlet end of the triaxial pressure system through a pipeline; the air outlet end of the triaxial pressure system is connected with a positive pressure adjusting system through a pipeline; the positive pressure adjusting system is connected with a flow determining system through a pipeline; a pressure loading system is connected with the triaxial pressuresystem; a vacuum degassing system is connected to a part between the positive pressure adjusting system and the flow determining system through a pipeline. The technical problems that the triaxial seepage device cannot change the humidity of the gas, cannot simulate the influence of the change of gas humidity of a coal mining site on coal permeability and the like are solved.

The invention discloses a method for calculating anisotropic absolute permeability of coal. A model expression is defined in the specification. The anisotropic characteristics of coal bodies are considered, so that the precision of coal permeability prediction is improved.

The invention discloses a tectonic coal permeability tester, which can simultaneously realize steady-state method and non-steady-state method permeability tests on irregular tectonic coal. The tectonic coal permeability tester comprises a core arranging chamber in which a sample is arranged, wherein two ends of the core arranging chamber are respectively provided with vents; two ends of the sample are planes, and space between the periphery of the sample and the inner wall of the core arranging chamber is filled with glass cement; one end of the core arranging chamber is connected with a pressure regulating valve by a pipeline, and the pressure regulating valve is communicated to a gas source; a flowmeter I and an upper stream container which are connected with each other in parallel are connected between the pressure regulating valve and the core arranging chamber; the other end of the core arranging chamber is respectively connected with a flowmeter II, a vacuum pump, and a downstream container through pipelines; a differential pressure gauge is connected between the vents in the two ends of the core arranging chamber. According to the tester, sampling is easy, a sample clamp holder is prevented from pressing and damaging the sample, and the tested permeability is more close to reality; the steady-state and non-steady-state tests can be performed, so the test range is wider, meanwhile the porosity of the sample can be tested, and acquired data are more.

The invention discloses a multi-dimensional data source lump coal permeability analysis method. A permeability model is established, influence factors of lump coal permeability are identified, and themulti-dimensional data source lump coal permeability analysis method is established so that an analysis result is more accurate. Meanwhile, the invention discloses a multi-dimensional data source lump coal permeability measurement device and method. The device comprises an adsorption and desorption system, an electro-hydraulic servo triaxial seepage test device, a gas source system, a vacuumizingsystem, a gas collection device and the like, deformation can be measured and used for analyzing the change rule of permeability, the relation between parameters while drilling and mechanical properties is established and serves as a permeability prediction sample, and the desorption rule of gas-containing coal under the high-temperature coupling of the constant-temperature environment and the middle line of the sample is studied, and finally, the data of the lump coal permeability influence factor under laboratory conditions is obtained so as to accurately analyze and measure the permeability of the lump coal.

The invention discloses a large-temperature-difference freeze-thaw cycle method for production increase of a surface borehole. Firstly, magnetized water is injected into a gas extraction pipe of the surface borehole in a pulsating manner; high-pressure nitrogen drives the magnetized water to enter the coal body; liquid nitrogen freezing is carried out on the magnetized water for many times and themagnetized water and high-temperature nitrogen are melted; the freezing expansion force of the magnetized water and the direct large-temperature-difference effect of the liquid nitrogen and the high-temperature nitrogen are utilized to jointly crack the coal body; by means of interaction of high-temperature and high-pressure nitrogen, liquid nitrogen and magnetized water, an ultra-large temperature difference effect is formed, the coal cracking effect is achieved, finally, the coal cracking effect and the crack expansion range can be effectively improved, the coal permeability is increased, and therefore large-flow, high-concentration and long-time gas extraction through ground drilling is achieved.

The invention discloses a drilling optimization method for extracting coal seam gas by drilling. The drilling optimization method comprises the following steps: 1, acquiring geological parameters of a coal seam to be researched; 2, constructing a gas extraction mathematical model considering the dynamic evolution of the coal permeability; 3, acquiring a drilling parameter design scheme; 4, constructing a coal-rock mass model, and obtaining a regression model of the maximum gas pressure between the drill holes and the standard pressure ratio; 5, optimizing the drilling parameters and acquiring a contour map of the drilling parameters; and 6, on-site drilling extraction of the coal seam to be researched. The method is simple in step and reasonable in design, the drilling parameters are optimized based on the ratio of the maximum gas pressure between the drill holes to the standard pressure, the extraction negative pressure, the drill hole diameter and the drill hole interval are optimized, it is guaranteed that coal seam gas extraction reaches the standard on the premise that the gas extraction effect is improved and the construction cost is reduced, coal seam gas extraction is accurate, and the coal seam gas extraction efficiency is improved. And a theoretical basis and technical guidance are provided for on-site extraction drilling hole arrangement.

The invention discloses a test method for evaluating the influence of rock deformation on coal permeability, which comprises the following steps of: applying boundary conditions for limiting displacement to a coal-rock combination sample by setting the structure of a seepage holder, and simulating the interaction condition of coal and a top plate in the coal reservoir gas development process; the method comprises the following steps: testing the deflection and coal deformation of a roof rock of a coal-rock combination under different pressure drop conditions, comparing the deflection and the coal deformation to determine the boundary condition of the coal-rock combination, and simulating the real stress state of coal and a roof in the coal reservoir gas development process and the deformation condition of the coal and the roof after stress; a basis is provided for establishing a mathematical model for finely describing the permeability of the coal reservoir, and the model is used for accurately guiding a coal reservoir gas development project, so that the time is saved, and the trial and error cost is reduced.