A carbon film is formed from carbon nanotube assemblies. In the carbon film, a pore distribution curve indicating the relationship between the pore size and the Log differential pore capacity obtained based on mercury intrusion porosimetry has at least one peak with a log differential pore capacity of 1.0 cm.sup.3/g or more within a pore size range of 10 nm or more and 100 m or less.

An evaluation method for different types of pore evolution in shale is related, which is applied to the field of unconventional oil and gas research. As the shale depth or maturity increases, different types of pores (including intergranular pores, intragranular pores, organic pores and fractures) developed in shale are constantly changing, which is important for shale oil and gas accumulation. The present invention starts from the high-resolution scanning electron micrography of shale, and respectively extracts the areal porosity of different types of pores based on the division criteria of different types of pores and pore identification in the established shale, and combines the low-temperature N.sub.2, CO.sub.2 adsorption experiments and the high-pressure mercury intrusion experiments to obtain the total pore volume and establish the evolution chart of different types of pores. The proposed method has an important application value for the exploration of unconventional shale oil and gas resources.

The invention simulates flows in a geological reservoir having a heterogeneous pore size. From laboratory measurements on samples taken in the geological reservoir, pore size distribution classes are determined and a triple-porosity model representative of each class is determined. The flow simulator according to the invention implements the triple-porosity model, a thermodynamic equation of state accounting for an equivalent dimension of the pores of the small-size medium, fluid exchanges exclusively between the large-pore and small-pore media and between the small-pore and fracture media, and the capillary pressure as a function of the saturation in a small-pore medium.

A pore analysis method is described which comprises the steps of generating a model of a medium, the model comprising a regular array of pores, the pores being connected to adjacent ones of the pores by throats, modifying the sizes of the pores and throats until the model of the medium is representative of the medium, simulating, using the model, the effect of percolation of the medium using a fluid at a first pressure, repeating the simulation step with progressively increasing intrusion pressures and noting, for each pore, the intrusion pressure at which intrusion of that pore occurs, and identifying, from the information relating to the intrusion pressure at which intrusion of each pore occurs and from the shape of the void size distribution, at least one pore that should be treated, during further analysis, as comprising a cluster of voids.

A method may comprise obtaining a formation sample, scanning the formation sample to form a data packet, loading the data packet on an information handling machine, performing a digital porous plate experiment with the data packet, and determining geometry of a pore throat in the formation sample. A system may comprise a computer tomographic machine configured to scan a formation sample and create a data packet from the scan and an information handling system. The information handling system may be configured to configured to perform a digital porous plate experiment with the data packet and determine geometry of a pore throat in the formation sample.

The present invention a method for determining the gas saturation of a tight reservoir. The method comprises the steps of: determining the pore size distribution of the tight reservoir rock sample, and calculating the free water saturation; calculating the water-membrane water saturation; calculating the corner water saturation; calculating the gas saturation of the tight reservoir rock sample according to the following equation:

S.sub.g=100S.sub.w wherein S.sub.w is the water saturation in %; S.sub.w is the sum of the free water saturation, the water saturation and the corner water saturation; S.sub.g is the gas saturation in %. The method for determining the gas saturation of a tight reservoir uses model calculations, which avoids errors in the determination results of the gas saturation caused by water volatilization, surface adsorption, and observation of water flow during experiments.

A method for inspecting a separation membrane structure includes an assembly step of sealing a separation membrane structure that includes a porous substrate and a separation membrane into a casing, and an inspection step of applying pressure to an inspection liquid that has filled a first main surface side of the separation membrane.

Irreducible water saturation of fluid-storing porous reservoir rock is determined using methods that include obtaining a reservoir rock sample from the underground fluid reservoir; performing mercury saturation measurements on the reservoir rock sample for different mercury injection pressure values to obtain mercury saturation values for the different mercury injection pressure values; and estimating the irreducible water saturation (Sw.sub.irr) from the mercury saturation values and the mercury injection pressure values by correcting for surface films of fluid retained on pore walls of the reservoir rock.

An evaluation method for different types of pore evolution in shale is related, which is applied to the field of unconventional oil and gas research. As the shale depth or maturity increases, different types of pores (including intergranular pores, intragranular pores, organic pores and fractures) developed in shale are constantly changing, which is important for shale oil and gas accumulation. The present invention starts from the high-resolution scanning electron micrography of shale, and respectively extracts the areal porosity of different types of pores based on the division criteria of different types of pores and pore identification in the established shale, and combines the low-temperature N.sub.2, CO.sub.2 adsorption experiments and the high-pressure mercury intrusion experiments to obtain the total pore volume and establish the evolution chart of different types of pores. The proposed method has an important application value for the exploration of unconventional shale oil and gas resources.

A method for determining lower radius limit of movable throat of shale is provided, and it includes: performing a low-temperature nitrogen adsorption test on a target shale to obtain first pore radii; performing a high-pressure mercury injection test on the target shale to obtain second pore radii; performing a nuclear magnetic resonance test on the target shale to obtain third pore radii; obtaining a relationship diagram of distribution frequencies and pore radii according to three pore radii; distinguishing, according to the pore radii, relationship diagram data, and performing normalization processing to determining a relationship curve of normalized frequency data and the pore radii; and determining a lower radius limit of movable throat of shale according to relationship curve. A problem of describing characteristics of shale occurrence space with complex pore structures and strong heterogeneity is solved, the method is suitable for determining lower radius limit of movable throat of shale.