47 results about "Apparent permeability" patented technology

The present invention belongs to the technical field of unconventional oil and gas development, and relates to a method for calculating apparent permeability of porous media of shale reservoir. The method includes the steps of: S1, collecting basic parameters of shale gas reservoir, calculating to obtain a Knudsen coefficient and a contribution coefficient; S2, utilizing the Knudsen coefficient tojudge the flow state of the gas in the capillary tube, and establishing the corresponding gas mass transport equation; S3, according to the water saturation of the reservoir rock sample, determiningthe effective flow radius corresponding to the capillaries of different sizes; S4, establishing unified mass transport equation of gas in different flow states in capillary tubes; S5. according to theunified mass transport equation, calculating the apparent permeability of the capillary tube, and superposing the apparent permeabilities of the capillary tubes with different sizes to obtain the apparent permeability of the whole shale core. The method of the invention takes into account the influence of different capillary sizes, distribution frequencies and water saturation of shale, and the method provided by the invention is closer to the real situation of the reservoir and obtains more accurate data.

The invention discloses a measurement method of rock core gas logging permeability. The method comprises the following steps of inputting values of rock core diameter and length into a computing chip; putting a rack core into a rubber sleeve, and applying confining pressure by a small-sized hand-cranking hydraulic pump; pushing a piston to a minimum calibration position of an inner cavity, and closing an emptying valve; setting the moving speed of the piston, starting a piston driving device, stopping working when the piston is moved to a maximum calibration position of the inner cavity, calculating the apparent permeability of rock core gas by the computing chip, and further calculating the rock core gas logging permeability to complete first-time measurement; opening the emptying valve, and then closing the emptying valve after the pressure of the inner cavity is balanced; repeating the previous steps, moving the piston to the minimum calibration position of the inner cavity, and carrying out measurement for the second time; and calculating the average value of the twice measured values by the computing chip to obtain the final rock core gas logging permeability. According to the measurement method, the rock core gas logging permeability can be measured for two times in the back and forth movement process of the piston, so that the measurement method is high in measurement efficiency and high in measurement speed, and has an important significance for rapid evaluation of rock samples collected in the field.

The invention discloses a shale reservoir permeability prediction method based on the improved Kozeny-Carman model, which corrects the shale reservoir pore cross section from non-circular pores to circular pores; uses the pore equivalent diameter to quantitatively characterize the pore size evolution ; Determine the pore size fractal factor based on the fractal coarsening theory; calculate the capillary length and the number of pores in the preset range according to the pore size fractal factor, calculate the pore volume by using the real-time pore equivalent radius and the capillary length, and use the capillary length and the preset range The matrix volume is calculated by the number of pores, the dynamic porosity is calculated by using the pore volume and the matrix volume, and the apparent permeability of a single capillary of different sections is calculated by using the real-time equivalent pore radius. Permeability calculates the apparent permeability of shale. The invention comprehensively considers the characteristics of the shale reservoir, dynamically characterizes the porosity of the shale reservoir based on the fractal theory, and applies the dynamic porosity to the quantitative characterization of the permeability of the shale reservoir.

The invention discloses a flow state evaluation method considering multi-scale effects of shale, comprising the following steps: S1, collecting basic parameters of shale cores; S2, establishing an apparent permeability calculation model considering multi-scale effects; S3, establishing a simultaneous There are 4 kinds of seepage models, combined with related algorithms to obtain the pressure response curves of the upstream chamber and the downstream chamber; S4, using the pulse decay method to experimentally measure the pressure response curves of the upstream chamber and the downstream chamber; S5, combining the core pressure response of different development states Model, fit the experimental data to calculate the pressure response curves of the upstream chamber and downstream chamber, and calculate the core parameters. The present invention establishes four kinds of seepage models that simultaneously exist in the shale core that considers the matrix of adsorption and desorption and the matrix + natural fractures, and calculates the pressure response curves in the upper and lower chambers, the pressure response curves obtained through calculation and the pressure measured by experiments The response curves were fitted to obtain the relevant parameters and distributions of the four flow regimes in the rock.

The invention discloses a method and system for interpreting the apparent permeability of low-permeability reservoirs in formations. Firstly, the curve of the permeability measurement value of the test sample as a function of gas pressure is determined, and then the Knudsen number of the test sample under different pressures is determined. The curve of the permeability measurement value of the test sample changing with the gas pressure is converted into the curve of the permeability measurement value of the test sample changing with the Knudsen number, and the curve of the permeability measurement value of the test sample changing with the Knudsen number Square method data fitting, determine the intrinsic permeability of the test sample, the wall influence parameters of the test sample, and the ratio of the slip distance of the test sample to the molecular mean free path, when determining the apparent permeability of the low-permeability reservoir in the formation , using the wall influence parameter of the test sample and the ratio of the test sample’s slip distance to the molecular mean free path to correct the wall slip effect, so as to more accurately explain the apparent permeability of low-permeability reservoirs in the formation.