CN110857927A

CN110857927A - Competitive adsorption detection method and device for carbon dioxide and methane in shale

Info

Publication number: CN110857927A
Application number: CN201810974232.5A
Authority: CN
Inventors: 王飞; 吕欣润
Original assignee: China University of Petroleum Beijing
Current assignee: China University of Petroleum Beijing
Priority date: 2018-08-24
Filing date: 2018-08-24
Publication date: 2020-03-03
Anticipated expiration: 2038-08-24
Also published as: CN110857927B

Abstract

The embodiment of the application provides a competitive adsorption detection method and a competitive adsorption detection device for carbon dioxide and methane in shale, wherein the competitive adsorption detection method comprises the following steps: after methane with the first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, the mass of the methane in the first adsorption state in the shale in the detection chamber is determined. Further, after the mixed gas of the carbon dioxide and the methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again, determining the mass of the second adsorption methane in the shale in the detection chamber; furthermore, according to the mass of the methane in the first adsorption state and the mass of the methane in the second adsorption state, competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure can be determined, so that efficient exploitation of shale gas can be reasonably guided.

Description

Competitive adsorption detection method and device for carbon dioxide and methane in shale

Technical Field

The embodiment of the application relates to the technical field of shale gas detection, in particular to a competitive adsorption detection method and device for carbon dioxide and methane in shale.

Background

Shale gas is huge in resource amount, and with the development of resource exploration technology, shale gas is considered to be unconventional natural gas with great mining value. Generally, shale gas mainly comprises: adsorbed methane and free methane (the content of adsorbed methane is counted to occupy 20% -85% of shale gas). Therefore, enhancing the recovery of adsorbed methane (otherwise known as adsorbed gas) is particularly important for shale gas stimulation.

Considering that shale has a greater adsorption capacity for carbon dioxide than methane, in the related art, carbon dioxide and methane (CH) are introduced into a shale reservoir₄) Competitive adsorption occurs to displace the adsorbed methane from the shale.

However, since the research on competitive adsorption of carbon dioxide and methane in the related art is relatively few, the influence of carbon dioxide on the quality of methane in an adsorption state in shale under the same methane partial pressure cannot be reasonably determined, and thus efficient exploitation of shale gas cannot be reasonably guided. Therefore, research on a detection mode of competitive adsorption of carbon dioxide and methane in shale is a problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides a competitive adsorption detection method and device for carbon dioxide and methane in shale, which realizes detection of competitive adsorption information of carbon dioxide to methane in shale under the same methane partial pressure, and therefore high-efficiency exploitation of shale gas can be reasonably guided.

In a first aspect, an embodiment of the present application provides a method for detecting competitive adsorption of carbon dioxide and methane in shale, including:

after methane with a first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, determining the mass of the methane in the first adsorption state in the shale in the detection chamber;

after the mixed gas of the carbon dioxide and the methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again, determining the mass of the methane in the second adsorption state in the shale in the detection chamber; wherein the volume ratio of the carbon dioxide to the methane is 1: 1; the second pressure value is 2 times of the first pressure value;

and determining competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure according to the mass of the first adsorption state methane and the mass of the second adsorption state methane.

In a possible implementation manner, after introducing pure methane with a first pressure value into a detection chamber of a nuclear magnetic resonance NMR apparatus, determining a mass of methane in a first adsorption state in shale in the detection chamber includes:

detecting first NMR information in the detection chamber by the NMR instrument; wherein the first NMR information is indicative of a relationship between the NMR signal in the detection chamber and a transverse relaxation time T2;

determining the mass of the first free methane and the mass of the first pore methane in the shale in the detection chamber according to the first NMR information, the relation information between the NMR signal and the mass of the free methane and the relation information between the NMR signal and the mass of the pore methane;

and determining the mass of the first adsorbed methane in the shale in the detection chamber according to the total mass of the methane with the first pressure value introduced into the detection chamber, the mass of the first free methane in the shale and the mass of the first pore methane.

In a possible implementation manner, after the mixed gas of carbon dioxide and methane with the pressure of the second pressure value is re-introduced into the detection chamber of the NMR instrument, determining the mass of the methane in the second adsorption state in the shale in the detection chamber includes:

detecting second NMR information in the detection chamber by the NMR instrument; wherein the second NMR information is indicative of a relationship between the NMR signal in the detection chamber and a transverse relaxation time T2;

determining the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber according to the second NMR information, the relation information between the NMR signal and the mass of the free methane and the relation information between the NMR signal and the mass of the pore methane;

and determining the mass of the second adsorbed methane in the shale in the detection chamber according to the total mass of the methane mixed with the carbon dioxide and introduced into the detection chamber, the mass of the second free methane in the shale and the mass of the second pore methane.

In one possible implementation, the determining the mass of the first free methane and the mass of the first pore methane in the shale in the detection chamber according to the first NMR information, the relationship information between the NMR signal and the mass of the free methane, and the relationship information between the NMR signal and the mass of the pore methane comprises:

determining NMR signals corresponding to the second peak and NMR signals corresponding to the third peak in the NMR signals according to the first NMR information; wherein, as T2 changes from small to large, the NMR signal in the first NMR information sequentially has a first peak, a second peak and a third peak;

determining the mass of the first pore state methane in the shale in the detection chamber according to the NMR signal corresponding to the second peak value and the relation information between the NMR signal and the mass of the pore state methane;

and determining the mass of the first free methane in the shale in the detection chamber according to the NMR signal corresponding to the third peak and the relation information between the NMR signal and the mass of the free methane.

In one possible implementation, the determining, from the second NMR information, the relationship information between the NMR signal and the mass of the free methane, and the relationship information between the NMR signal and the mass of the pore methane, the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber includes:

determining NMR signals corresponding to the second peak and NMR signals corresponding to the third peak in the NMR signals according to the second NMR information; wherein, as T2 changes from small to large, the NMR signal in the second NMR information sequentially has a first peak, a second peak and a third peak;

determining the mass of the second pore state methane in the shale in the detection chamber according to the NMR signal corresponding to the second peak value and the relation information between the NMR signal and the mass of the pore state methane;

and determining the mass of the second free methane in the shale in the detection chamber according to the NMR signal corresponding to the third peak and the relation information between the NMR signal and the mass of the free methane.

In one possible implementation, the method further includes:

acquiring information on the relationship between the NMR signal and the mass of the free methane and acquiring information on the relationship between the NMR signal and the mass of the pore methane.

In a possible implementation manner, the acquiring information of the relationship between the NMR signal and the mass of the free methane includes:

determining a first volume of a detection chamber of the NMR instrument;

respectively introducing methane with different pressure values into the detection chambers of the NMR instrument, and respectively detecting NMR signals of free methane in the detection chambers corresponding to the pressure values by the NMR instrument;

determining the mass of methane corresponding to each pressure value according to each pressure value, the first volume and a state equation;

and determining the relation information between the NMR signal and the mass of the free methane in the detection chamber according to the NMR signal and the mass of the free methane in the detection chamber corresponding to each pressure value.

In one possible implementation, the acquiring information on the relationship between the NMR signal and the mass of the methane in the pore state includes:

determining a second volume of the detection chamber of the NMR instrument after adding the filler to the detection chamber of the NMR instrument;

respectively introducing methane with different pressure values into a detection chamber of the NMR instrument, and respectively detecting NMR signals of the pore methane in the detection chamber corresponding to each pressure value through the NMR instrument;

determining the mass of the methane corresponding to each pressure value according to each pressure value, the second volume and the state equation;

and determining the relation information between the NMR signal and the mass of the pore state methane in the detection chamber according to the NMR signal of the pore state methane in the detection chamber and the mass of the methane corresponding to each pressure value.

In a second aspect, an embodiment of the present application provides a competitive adsorption detection apparatus for carbon dioxide and methane in shale, including:

the device comprises a first determination module, a second determination module and a third determination module, wherein the first determination module is used for determining the mass of methane in a first adsorption state in shale in a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument after methane with a first pressure value is introduced into the detection chamber;

the second determination module is used for determining the mass of the second adsorption methane in the shale in the detection chamber after the mixed gas of the carbon dioxide and the methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again; wherein the volume ratio of the carbon dioxide to the methane is 1: 1; the second pressure value is 2 times of the first pressure value;

and the third determination module is used for determining competitive adsorption information of the carbon dioxide to the methane in the shale under the same methane partial pressure according to the mass of the first adsorption state methane and the mass of the second adsorption state methane.

In one possible implementation manner, the first determining module includes:

a first detection unit for detecting first NMR information in the detection chamber by the NMR instrument; wherein the first NMR information is indicative of a relationship between the NMR signal in the detection chamber and a transverse relaxation time T2;

a first determining unit, configured to determine a mass of the first free methane and a mass of the first pore methane in the shale in the detection chamber according to the first NMR information, the relationship information between the NMR signal and the mass of the free methane, and the relationship information between the NMR signal and the mass of the pore methane;

the second determination unit is used for determining the mass of the first adsorbed methane in the shale in the detection chamber according to the total mass of the methane with the pressure value of the first pressure value introduced into the detection chamber, the mass of the first free methane in the shale and the mass of the first pore methane;

and/or the second determination module comprises:

a second detection unit for detecting second NMR information in the detection chamber by the NMR instrument; wherein the second NMR information is indicative of a relationship between the NMR signal in the detection chamber and a transverse relaxation time T2;

a third determining unit, configured to determine a mass of the second free methane and a mass of the second pore methane in the shale in the detection chamber according to the second NMR information, the relationship information between the NMR signal and the mass of the free methane, and the relationship information between the NMR signal and the mass of the pore methane;

and the fourth determination unit is used for determining the mass of the second adsorbed methane in the shale in the detection chamber according to the total mass of the methane mixed with the carbon dioxide and introduced into the detection chamber, the mass of the second free methane in the shale and the mass of the second pore methane.

According to the competitive adsorption detection method and device for carbon dioxide and methane in shale, after methane with the first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, the mass of the methane in the first adsorption state in the shale in the detection chamber is determined. Further, after the mixed gas of the carbon dioxide and the methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again, determining the mass of the second adsorption methane in the shale in the detection chamber; since the volume ratio of carbon dioxide to methane is 1:1 and the second pressure value is 2 times the first pressure value, the partial pressure of methane is the same between the case where the mixed gas of carbon dioxide and methane having the second pressure value is introduced into the detection chamber of the NMR apparatus and the case where methane having the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus. Furthermore, according to the mass of the methane in the first adsorption state and the mass of the methane in the second adsorption state, competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure can be determined, so that efficient exploitation of shale gas can be reasonably guided.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of a detection apparatus used in the competitive adsorption detection method for carbon dioxide and methane in shale according to the present application;

FIG. 2 is a schematic illustration of magnetization provided by an embodiment of the present application;

FIG. 3 is a schematic view of magnetization vectors provided in an embodiment of the present application;

fig. 4 is a schematic flow chart of a method for detecting competitive adsorption of carbon dioxide and methane in shale according to an embodiment of the present disclosure;

FIG. 5 is a graph showing the relationship between NMR signal and mass of free methane provided in an example of the present application;

FIG. 6 is a graph showing the relationship between NMR signal and mass of methane in a porous state as provided in an example of the present application;

FIG. 7 is a schematic representation of first NMR information provided in an embodiment of the present application;

FIG. 8 is a schematic diagram of competitive adsorption information of carbon dioxide on methane in shale under the same methane partial pressure provided by an embodiment of the application;

FIG. 9 is a schematic representation of second NMR information provided in examples herein;

fig. 10 is a schematic structural diagram of a device for detecting competitive adsorption of carbon dioxide and methane in shale according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

First, some words referred to in the embodiments of the present application will be explained.

The free methane referred to in the examples of the present application refers to methane in a free state (alternatively referred to as free gas).

Reference in the examples herein to adsorbed methane is to methane in an adsorbed state (otherwise known as free gas).

The reference to the porous methane in the examples of the present application refers to methane in a porous state (otherwise known as pore gas).

Competitive adsorption in the examples of the present application refers to the phenomenon of mutual competition between components when they are adsorbed on the surface of an adsorbent.

The first NMR information referred to in the examples of the present application is indicative of the relationship between the NMR signal and the transverse relaxation time T2 of methane in the detection chamber of the nuclear magnetic resonance NMR apparatus after the methane having a first pressure value is introduced into the detection chamber. Illustratively, as T2 changes from small to large, the NMR signal will show a first peak, a second peak, and a third peak in that order. Considering that T2 is related to the binding force and the degree of freedom of hydrogen protons, and the binding degree of hydrogen protons is closely inseparable from the internal structure of methane, i.e. the smaller the pore size, the greater the binding degree of methane existing in the pores, and the shorter the corresponding transverse relaxation time T2, the first peak represents an adsorbed methane binding peak, the second peak represents a pore methane binding peak, and the third peak represents a free methane binding peak.

Alternatively, the first NMR information may be present in the form of a figure (e.g., with the abscissa T2 and the ordinate the NMR signal), and may also be present in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

The second NMR information referred to in the examples of the present application is used to indicate the relationship between the NMR signal of methane in the detection chamber and the transverse relaxation time T2 after the mixed gas of carbon dioxide and methane at the second pressure value is re-introduced into the detection chamber of the NMR instrument. Illustratively, as T2 changes from small to large, the NMR signal will exhibit a first peak (representing an adsorbed methane binding peak), a second peak (representing a pore methane binding peak), and a third peak (representing a free methane binding peak) in that order.

Optionally, the existence form of the second NMR information may refer to the existence form of the first NMR information, which is not described in detail in this embodiment.

The relation information between the NMR signal and the mass of the free methane related to the embodiment of the application is used for indicating the NMR signal of the free methane and the mass of the free methane corresponding to the NMR signal. For example, the relationship information between the NMR signal and the mass of the free methane can be presented in the form of a figure (for example, the abscissa represents the mass of the free methane, and the ordinate represents the NMR signal of the free methane), and can also be presented in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

The relation information between the NMR signal and the mass of the pore state methane referred to in the examples of the present application is used for indicating the NMR signal of the pore state methane and the mass of the pore state methane corresponding to the NMR signal. For example, the relationship information between the NMR signal and the mass of the pore state methane can be presented in the form of a figure (for example, the abscissa is the mass of the pore state methane, and the ordinate is the NMR signal of the pore state methane), and can also be presented in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

The information on the relationship between the NMR signal and the mass of the adsorbed methane referred to in the examples of the present application is used to indicate the NMR signal of the adsorbed methane and the mass of the adsorbed methane corresponding thereto. Illustratively, the information on the relationship between the NMR signal and the mass of the adsorbed methane can be presented in the form of a figure (e.g., the abscissa represents the mass of the adsorbed methane and the ordinate represents the NMR signal of the adsorbed methane), and can also be presented in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

The state equations involved in the embodiments of the present application may include the following:

wherein p represents the pressure of methane (in Pa) and V represents the volume of the detection chamber (in m)³) Z represents the compression factor, n represents the mass of methane (in mol), R represents the gas constant 8.314J/(mol K), T represents the detection chamber temperature (in K), M represents the mass of methane (in g), and M represents the molar mass of methane 16 g/mol.

In the related art, the research on competitive adsorption of carbon dioxide and methane is less, and the influence of carbon dioxide on the quality of methane in an adsorption state in shale under the same methane partial pressure cannot be reasonably determined, so that the efficient exploitation of shale gas cannot be reasonably guided.

In consideration of the fact that the volume ratio of carbon dioxide to methane is 1:1 when the mixed gas of carbon dioxide and methane having the second pressure value is introduced into the detection chamber of the NMR apparatus again and the second pressure value is 2 times the first pressure value when pure methane is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus, the partial pressure of methane in the mixed gas of carbon dioxide and methane having the second pressure value is the same as that in the mixed gas of carbon dioxide and methane having the first pressure value when methane having the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus again. In the embodiment of the application, competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure can be determined according to the mass of the first adsorption state methane in the shale determined when methane with the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR instrument and the mass of the second adsorption state methane in the shale determined when the mixed gas of carbon dioxide and methane with the second pressure value is introduced into the detection chamber of the NMR instrument again, so that efficient exploitation of shale gas can be guided reasonably.

Fig. 1 is a schematic structural diagram of a detection device applied to the competitive adsorption detection method for carbon dioxide and methane in shale. As shown in fig. 1, the detection device may include: the device comprises a gas source, a pressure regulating valve, a gas inlet switch, a reference tank, a pressure gauge, a balance switch, an emptying switch and a Nuclear Magnetic Resonance (NMR) instrument; wherein the NMR instrument includes a detection chamber. Of course, other devices may be included in the detection apparatus, which is not limited in the embodiments of the present application.

The following examples of the present application provide a brief description of the measurement principle of the NMR instrument for measuring methane in shale.

Fig. 2 is a schematic view of magnetization provided in an embodiment of the present application, and fig. 3 is a schematic view of a magnetization vector provided in an embodiment of the present application. As shown in FIG. 2, after the methane sample is placed in a constant magnetic field B0, a macroscopic magnetization M is generated along the direction of the applied magnetic field (e.g., the z-axis). Further, as shown in FIG. 3, after an alternating RF pulse field B1 is applied in a direction perpendicular to the z-axis (e.g., the x-axis), the magnetization vector M will tend to be in the x-y plane and at an angle to the z-axis that varies with time. 1) As the angle increases, the potential increases, this energy increment being provided by the applied alternating magnetic field B1 (radio frequency field) (the alternating electromagnetic field can be applied either continuously or in short pulses). 2) When the included angle is reduced, the potential energy is reduced, the energy is given to an external alternating magnetic field, the energy exchange only occurs when the angular frequency of the alternating magnetic field meets the condition that omega is gamma B1 omega 1, the phenomenon is nuclear magnetic resonance, the formula gamma B1 omega 1 is the resonance condition, and the resonance frequency is gamma B1. At this time, if a detection coil is built in the xy plane, an induced electromotive force is generated, which is a detected NMR signal.

After the rf pulse B1 ends, 2 relaxation processes are involved: longitudinal relaxation and transverse relaxation. The state when the longitudinal component of the magnetization vector increases during relaxation, eventually reaching equilibrium, is called longitudinal relaxation (T1); the transverse component of the magnetization vector during relaxation gradually decays and eventually reaches a value of zero, called transverse relaxation (T2). The transverse relaxation time data can reflect the relative amount of methane in different occurrence states (such as free methane, pore methane and/or adsorption methane), so that the corresponding adsorption condition of methane can be obtained according to the transverse relaxation time data.

Fig. 4 is a schematic flow chart of a method for detecting competitive adsorption of carbon dioxide and methane in shale according to an embodiment of the present disclosure. The execution main body of the embodiment may be a device for detecting competitive adsorption of carbon dioxide and methane in shale, and the device may be implemented by software and/or hardware. As shown in fig. 4, the method of this embodiment may include:

s401, after methane with a first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, determining the mass of the methane in the first adsorption state in the shale in the detection chamber.

In this step, one possible implementation manner is: after methane with the pressure of the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR instrument, the mass of the methane in the first adsorption state in the shale in the detection chamber can be determined through the first NMR information of the methane in the detection chamber measured by the NMR instrument and the acquired relation information between the NMR signal and the mass of the methane in the adsorption state.

Illustratively, the NMR signal of the methane in the first adsorption state corresponding to the binding peak of the methane in the adsorption state is determined through the first NMR information of the methane in the detection chamber measured by the NMR instrument, and the mass (namely the mass of the methane in the first adsorption state) corresponding to the NMR signal of the methane in the first adsorption state is determined according to the NMR signal of the methane in the first adsorption state and the acquired relation information between the NMR signal of the methane in the adsorption state and the mass.

Another possible implementation: after methane with the pressure of the first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, the mass of the methane in the first adsorption state in the shale in the detection chamber can be determined through the first NMR information of the methane in the detection chamber, the acquired relation information between the NMR signal and the mass of the free methane, the relation information between the NMR signal and the mass of the methane in the pore state, and the total mass of the methane with the pressure of the first pressure value introduced into the detection chamber, which are measured by the NMR instrument.

Illustratively, detecting first NMR information in the detection chamber by an NMR instrument; further, determining the mass of the first free methane and the mass of the first pore methane in the shale in the detection chamber according to the first NMR information, the relation information between the NMR signal and the mass of the free methane and the relation information between the NMR signal and the mass of the pore methane; and further, determining the mass of the first adsorbed methane in the shale in the detection chamber according to the total mass of the methane with the pressure of the first pressure value in the detection chamber, the mass of the first free methane in the shale and the mass of the first pore methane.

Specifically, after methane with a first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, first NMR information of the methane in the detection chamber is detected through the NMR instrument; according to the first NMR information, the NMR signal can sequentially generate a first peak (representing an adsorbed methane binding peak), a second peak (representing a pore methane binding peak) and a third peak (representing a free methane binding peak) along with the change of T2 from small to large.

Further, the NMR signal corresponding to the second peak (i.e., the NMR signal of the first pore state methane) and the NMR signal corresponding to the third peak (i.e., the NMR signal of the first free state methane) in each NMR signal are determined according to the first NMR information, so as to further determine the mass (i.e., the mass of the first pore state methane) corresponding to the NMR signal of the first pore state methane according to the NMR signal corresponding to the second peak (i.e., the NMR signal of the first pore state methane) and the relationship information between the NMR signal and the mass of the pore state methane, and determine the mass (i.e., the mass of the first free state methane) corresponding to the NMR signal of the first free state methane according to the NMR signal (i.e., the NMR signal of the first free state methane) corresponding to the third peak and the relationship information between the NMR signal and the mass of the free state methane.

Further, the mass of the first adsorbed methane in the shale in the detection chamber can be determined by subtracting the mass of the first free methane and the mass of the first pore methane from the total mass of methane with the first pressure value introduced into the detection chamber.

Of course, the mass of the methane in the first adsorption state in the shale in the detection chamber can also be determined by other means in the embodiment of the present application, which is not limited in the example of the present application.

S402, after the mixed gas of the carbon dioxide and the methane with the pressure of the second pressure value is introduced into the detection chamber of the NMR instrument again, determining the mass of the second adsorption methane in the shale in the detection chamber; wherein the volume ratio of the carbon dioxide to the methane is 1: 1; the second pressure value is 2 times the first pressure value.

In this step, one possible implementation manner is: after the mixed gas of the carbon dioxide and the methane with the pressure of the second pressure value is introduced into the detection chamber of the NMR instrument again, the mass of the methane in the second adsorption state in the shale in the detection chamber can be determined through the second NMR information of the methane in the detection chamber measured by the NMR instrument and the acquired relation information between the NMR signal and the mass of the methane in the adsorption state.

Illustratively, the NMR signal of the methane in the second adsorption state corresponding to the bound peak of the methane in the adsorption state is determined from the second NMR information of the methane in the detection chamber measured by the NMR instrument, and the mass (i.e., the mass of the methane in the second adsorption state) corresponding to the NMR signal of the methane in the second adsorption state is determined from the NMR signal of the methane in the second adsorption state and the acquired relationship information between the NMR signal and the mass of the methane in the adsorption state.

Another possible implementation: after the mixed gas of the carbon dioxide and the methane with the pressure of the second pressure value is introduced into the detection chamber of the NMR instrument again, the mass of the second adsorption methane in the shale in the detection chamber can be determined through the second NMR information of the methane in the detection chamber, the acquired relation information between the NMR signal and the mass of the free methane, the relation information between the NMR signal and the mass of the pore methane, and the total mass of the methane mixed with the carbon dioxide and introduced into the detection chamber, which are measured by the NMR instrument.

Illustratively, detecting second NMR information in the detection chamber by an NMR instrument; further, determining the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber according to the second NMR information, the relation information between the NMR signal and the mass of the free methane and the relation information between the NMR signal and the mass of the pore methane; and further, determining the mass of the second adsorbed methane in the shale in the detection chamber according to the total mass of the methane mixed with the carbon dioxide and introduced into the detection chamber, the mass of the second free methane in the shale and the mass of the second pore methane.

Specifically, after the mixed gas of carbon dioxide and methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again, second NMR information of the methane in the detection chamber is detected through the NMR instrument; wherein, according to the second NMR information, as T2 changes from small to large, the NMR signal will sequentially have a first peak (representing an adsorbed methane binding peak), a second peak (representing a pore methane binding peak), and a third peak (representing a free methane binding peak).

Further, the NMR signal corresponding to the second peak (i.e., the NMR signal of the second pore state methane) and the NMR signal corresponding to the third peak (i.e., the NMR signal of the second free state methane) in each NMR signal are determined according to the second NMR information, so as to further determine the mass (i.e., the mass of the second pore state methane) corresponding to the NMR signal of the second pore state methane according to the NMR signal corresponding to the second peak (i.e., the NMR signal of the second pore state methane) and the relationship information between the NMR signal and the mass of the pore state methane, and determine the mass (i.e., the mass of the second free state methane) corresponding to the NMR signal of the second free state methane according to the NMR signal (i.e., the NMR signal of the second free state methane) corresponding to the third peak and the relationship information between the NMR signal and the mass of the free state methane.

Further, the mass of the second adsorbed methane in the shale in the detection chamber may be determined by subtracting the mass of the second free methane and the mass of the second pore methane from the total mass of methane mixed with the carbon dioxide and introduced into the detection chamber.

Of course, the mass of the methane in the second adsorption state in the shale in the detection chamber can also be determined by other means in the embodiments of the present application, which are not limited in the examples of the present application.

And S403, determining competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure according to the mass of the methane in the first adsorption state and the mass of the methane in the second adsorption state.

It is considered that since the volume ratio of carbon dioxide to methane is 1:1 and the second pressure value is 2 times the first pressure value, the partial pressure of methane is the same in the case where the mixed gas of carbon dioxide and methane having the second pressure value is introduced into the detection chamber of the NMR apparatus and the case where methane having the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus.

In this step, according to the mass of the first adsorbed methane in the shale when the methane with the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus determined in step S401, and the mass of the second adsorbed methane in the shale when the mixed gas of the carbon dioxide and the methane with the second pressure value is introduced into the detection chamber of the NMR apparatus again determined in step S402, competitive adsorption information of the carbon dioxide on the methane in the shale (for example, change information of the mass of the adsorbed methane caused by competitive adsorption of the carbon dioxide, etc.) under the same methane partial pressure can be determined, so that efficient exploitation of the shale gas can be reasonably guided.

It should be noted that, in order to ensure the accuracy of the detection result, it is necessary to evacuate the gas in the detection chamber of the NMR instrument and to discharge the gas such as methane and carbon dioxide in the shale in the detection chamber before step S402. Specific evacuation and/or discharge modes can be referred to in the related art, and are not limited in the examples of the present application.

It should be noted that, in the embodiment of the present application, the order of executing steps S401 and S402 is not limited, for example, step S401 is executed first and then step S402 is executed, or step S402 is executed first and then step S401 is executed.

In the embodiment of the application, after methane with a first pressure value is introduced into a detection chamber of a Nuclear Magnetic Resonance (NMR) instrument, the mass of the methane in the first adsorption state in the shale in the detection chamber is determined. Further, after the mixed gas of the carbon dioxide and the methane with the pressure of a second pressure value is introduced into the detection chamber of the NMR instrument again, determining the mass of the second adsorption methane in the shale in the detection chamber; since the volume ratio of carbon dioxide to methane is 1:1 and the second pressure value is 2 times the first pressure value, the partial pressure of methane is the same between the case where the mixed gas of carbon dioxide and methane having the second pressure value is introduced into the detection chamber of the NMR apparatus and the case where methane having the first pressure value is introduced into the detection chamber of the nuclear magnetic resonance NMR apparatus. Furthermore, according to the mass of the methane in the first adsorption state and the mass of the methane in the second adsorption state, competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure can be determined, so that efficient exploitation of shale gas can be reasonably guided.

On the basis of the foregoing example, another embodiment of the present application provides a method for detecting competitive adsorption of carbon dioxide and methane in shale, further including: information on the relationship between the NMR signal and the mass of free methane and information on the relationship between the NMR signal and the mass of the methane in a pore state are obtained.

The following examples of the present application describe the manner of obtaining information on the relationship between the NMR signal and the mass of free methane and the manner of obtaining information on the relationship between the NMR signal and the mass of pore methane, respectively.

Illustratively, by determining a first volume of a detection chamber of the NMR instrument. Further, methane with different pressure values is respectively introduced into the detection chambers of the NMR instrument (because shale is not placed in the detection chambers, the methane in the detection chambers belongs to free methane), and the NMR signals of the free methane in the detection chambers corresponding to the pressure values are respectively detected by the NMR instrument. Further, the mass of methane corresponding to each pressure value can be determined according to each pressure value, the first volume and the equation of state (as shown in the above formula 1). And further, determining the relation information between the NMR signal and the mass of the free methane in the detection chamber according to the NMR signal and the mass of the free methane in the detection chamber corresponding to each pressure value. For example, assuming that the NMR signal of the free methane in the detection chamber corresponding to the pressure P1 is N1 and the mass m1 of the free methane corresponding to the pressure P1, the NMR signal of the free methane in the detection chamber corresponding to the pressure P2 is N2 and the mass m2 of the free methane corresponding to the pressure P2, the NMR signal of the free methane in the detection chamber corresponding to the pressure P3 is N3, and the mass m3 of the free methane corresponding to the pressure P3, the relationship information between the NMR signal and the mass of the free methane can be determined; for example, the relationship information between the NMR signal and the mass of the free methane can be presented in the form of a figure (for example, the abscissa represents the mass of the free methane, and the ordinate represents the NMR signal of the free methane), and can also be presented in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

Of course, the information of the relationship between the NMR signal and the mass of the free methane can also be determined by other means in the embodiments of the present application, which is not limited in the examples of the present application.

Illustratively, the second volume of the detection chamber of the NMR instrument is determined by adding a filler (e.g., quartz sand) to the detection chamber of the NMR instrument. Further, methane with different pressure values is respectively introduced into the detection chambers of the NMR instrument (because the detection chambers are filled with quartz sand, the methane in the detection chambers belongs to the methane in a pore state), and NMR signals of the methane in the pore state in the detection chambers corresponding to the pressure values are respectively detected by the NMR instrument. Further, the mass of methane corresponding to each pressure value is determined according to each pressure value, the second volume and the equation of state (as shown in the above formula 1). And further, determining the relation information between the NMR signal and the mass of the pore state methane in the detection chamber according to the NMR signal and the methane mass of the pore state methane in the detection chamber corresponding to each pressure value. For example, assuming that the NMR signal of the pore state methane in the detection chamber corresponding to the pressure P11 is N11 and the mass m11 of the pore state methane corresponding to the pressure P11, the NMR signal of the pore state methane in the detection chamber corresponding to the pressure P22 is N22 and the mass m22 of the pore state methane corresponding to the pressure P22, the NMR signal of the pore state methane in the detection chamber corresponding to the pressure P33 is N33 and the mass m33 of the pore state methane corresponding to the pressure P33, the relationship information between the NMR signal and the mass of the pore state methane can be determined; for example, the relationship information between the NMR signal and the mass of the pore state methane can be presented in the form of a figure (for example, the abscissa is the mass of the pore state methane, and the ordinate is the NMR signal of the pore state methane), and can also be presented in the form of a table; of course, the present invention may also exist in other forms, and the present invention is not limited to these forms.

The embodiment of the application provides an implementation mode for obtaining the relation information between the NMR signal and the mass of the free methane and obtaining the relation information between the NMR signal and the mass of the pore methane, so that the mass of the free methane and the mass of the pore methane in the shale in the detection chamber can be determined conveniently, and the mass of the adsorbed methane can be determined according to the mass of the free methane and the mass of the pore methane in the shale in the detection chamber.

The following examples of the present application describe how a competitive adsorption detection method for carbon dioxide and methane in shale can be implemented, for example, with a NMR instrument as a macro mr12-150H-I large-scale nuclear magnetic resonance analyzer. Illustratively, the parameters of the NMR instrument may include, but are not limited to, at least one of: the resonance frequency was 11.798MHz, the magnet strength was 0.28T, the coil diameter was 70mm, and the magnet temperature was 32 ℃.

(1) Information on the relationship between the NMR signal and the mass of free methane and the NMR signal and the mass of pore methane is determined by measuring the NMR signals of methane in the corresponding detection chambers under isothermal conditions (e.g., 25 ℃ C.).

Step 11) measuring the volume V of the reference tank_{Ginseng radix (Panax ginseng C.A. Meyer)}And the volume V of the detection chamber.

Turning on an air inlet switch, introducing methane into the reference tank, and recording the pressure p1 of the reference tank; opening the balance switch, leading the methane in the reference tank into the detection chamber, and recording the pressure p2 after the methane is balanced, namely, the formula 2: p 1V_{Ginseng radix (Panax ginseng C.A. Meyer)}＝p2*(V_{Ginseng radix (Panax ginseng C.A. Meyer)}+ V). Further, after placing a reference column of known volume (e.g., a teflon column) into the detection chamber, the gas inlet switch is opened, methane is pumped into the reference tank, and the pressure p3 of the reference tank is recorded; the equilibrium switch is opened, methane in the reference tank is introduced into the detection chamber, and after equilibrium, the pressure p4 is recorded, so that formula 3 can be obtained: p 3V_{Ginseng radix (Panax ginseng C.A. Meyer)}＝p4*(V_{Ginseng radix (Panax ginseng C.A. Meyer)}+V-V_Column). Further, the volume V of the reference tank can be determined according to equation 2 and equation 3_{Ginseng radix (Panax ginseng C.A. Meyer)}And the volume V of the detection chamber. Of course, the volume V of the reference tank can be determined in other realizable manners in the embodiment of the application_{Ginseng radix (Panax ginseng C.A. Meyer)}And the volume V of the detection chamber, which is not limited in the embodiments of the present application.

Illustratively, assume that p1 is 3.14MPa, p2 is 1.28MPa, p3 is 3.84MPa, p4 is 1.76MPa, and V_ColumnIs 12.81cm³The volume V of the reference tank can be determined according to the above equations 2 and 3_{Ginseng radix (Panax ginseng C.A. Meyer)}Is 26.5684cm³And the volume V of the detection chamber is 44.2116cm³。

And 12) determining the relation information between the NMR signal and the mass of the free methane.

And (3) as shown in the figure 1, vacuumizing the detection chamber through an emptying switch, introducing methane with different pressure values into the detection chamber, and measuring the NMR signals of the free methane in the detection chamber corresponding to the different pressure values. Further, the mass of the free methane corresponding to the different pressure values is determined according to the different pressure values, the volume V of the detection chamber and the state equation (as shown in the above formula 1), and further, the relationship information between the NMR signal and the mass of the free methane is determined.

Illustratively, methane gas of 0.09-3.59MPa is respectively introduced into the detection chambers, and NMR signals of free methane in the detection chambers corresponding to different pressure values are measured. Further, the mass of the free methane corresponding to the different pressure values is determined according to the different pressure values, the volume V of the detection chamber, and the equation of state (as shown in the above formula 1), and then the relationship information between the NMR signal and the mass of the free methane as shown in fig. 5 (fig. 5 is a schematic diagram of the relationship between the NMR signal and the mass of the free methane provided in this embodiment of the present application) is determined.

Step 13) the volume V' of the test chamber after filling with quartz sand was measured.

Referring to FIG. 1, the volume V' of the chamber filled with silica sand can be determined by evacuating the chamber through an evacuation switch and filling the chamber with dried silica sand in step 11.

Exemplarily, assume that p1 is 8.48MPa, p2 is 4.30MPa, and the volume V of the reference tank_{Ginseng radix (Panax ginseng C.A. Meyer)}Is 26.5684cm³From equation 2 above, the volume V' of the detection chamber is determined to be 25.83 ml.

Step 14) information on the relationship between NMR signal and mass of the pore state methane is determined.

And (3) as shown in the figure 1, vacuumizing the detection chamber through an emptying switch, introducing methane with different pressure values into the detection chamber, and measuring the NMR signals of the pore methane in the detection chamber corresponding to the different pressure values. Further, the mass of the pore state methane corresponding to the different pressure values is determined according to the different pressure values, the volume V' of the detection chamber and the state equation (as the above formula 1), and further, the relationship information between the NMR signal and the mass of the pore state methane is determined.

Illustratively, methane gas of 0.14-7MPa is respectively introduced into the detection chambers, and NMR signals of the pore methane in the detection chambers corresponding to different pressure values are measured. Further, the mass of the pore state methane corresponding to the different pressure values is determined according to the different pressure values, the volume V' of the detection chamber and the equation of state (as shown in the above formula 1), and then the relationship information between the NMR signal and the mass of the pore state methane as shown in fig. 6 (fig. 6 is a schematic diagram of the relationship between the NMR signal and the mass of the pore state methane provided by the embodiment of the present application) is determined.

(2) The quality of methane in an adsorption state of pure methane and methane-carbon dioxide 1:1 mixed gas in the shale is detected under the isothermal condition and the same methane partial pressure, so that the competitive adsorption effect of the carbon dioxide in the shale on the methane is quantitatively evaluated.

Step 21) the volume V "of the detection chamber after filling with shale powder is measured.

After the shale powder sample is dried in an oven (e.g., for 24 hours and at a temperature of 90 ℃) and placed in the testing chamber, the volume V "of the testing chamber filled with shale powder can be determined by referring to step 11 above.

Step 22) determining the mass of methane in the first adsorption state in the shale in the detection chamber of the NMR instrument when pure methane is introduced into the detection chamber.

After pure methane with a pressure value of p0 was passed into the detection chamber of the NMR instrument, the first NMR information of methane (indicating the relationship between the NMR signal and the transverse relaxation time T2 of methane in the detection chamber) was measured after the shale powder had sufficiently adsorbed methane. Further, the mass of the first free methane and the mass of the first pore methane in the shale in the detection chamber are determined based on the first NMR information, the information on the relationship between the NMR signal and the mass of the free methane determined in step 12, and the information on the relationship between the NMR signal and the mass of the pore methane determined in step 14. Further, the mass of the methane in the first adsorbed state in the shale in the detection chamber is determined according to the total mass of the pure methane with the pressure value p0, the mass of the methane in the first free state in the shale and the mass of the methane in the first pore state.

Optionally, the pressure value of the pure methane introduced into the detection chamber may be changed, and the above step 22 may be repeatedly performed to determine the mass of the methane in the first adsorption state in the shale in the detection chamber of the NMR instrument when the pure methane with different pressure values is introduced into the detection chamber.

Illustratively, methane gas of 0.1-2MPa is respectively introduced into the detection chambers, and first NMR information of methane in the detection chambers corresponding to different pressure values as shown in fig. 7 (fig. 7 is a schematic diagram of the first NMR information provided in the embodiment of the present application) is measured. As shown in fig. 7, the NMR signal will have a first peak, a second peak, and a third peak in that order as T2 changes from small to large. Since T2 is related to the binding force and the degree of freedom of hydrogen protons, and the binding degree of hydrogen protons is closely related to the internal structure of methane, i.e., the smaller the pore size, the greater the binding degree of methane existing in the pores, and the shorter the corresponding transverse relaxation time T2, the first peak represents an adsorbed methane binding peak, the second peak represents a pore methane binding peak, and the third peak represents a free methane binding peak, as shown in fig. 7.

Further, for each pressure value of methane introduced into the detection chamber, determining the NMR signal corresponding to the second peak (i.e. the NMR signal of the methane in the first pore state) and the NMR signal corresponding to the third peak (i.e. the NMR signal of the methane in the first free state) in the NMR signals according to the corresponding first NMR information, so as to further determine the mass corresponding to the NMR signal of the first pore state methane (namely the mass of the first pore state methane) at the pressure value according to the NMR signal corresponding to the second peak (namely the NMR signal of the first pore state methane) and the relation information between the NMR signal and the mass of the pore state methane, and determining the mass corresponding to the NMR signal of the first free state methane (namely the mass of the first free state methane) at the pressure value according to the NMR signal corresponding to the third peak (namely the NMR signal of the first free state methane) and the relation information between the NMR signal and the mass of the free state methane.

Further, for each pressure value of methane introduced into the detection chamber, the mass of the first free methane and the mass of the first pore methane in the shale at the pressure value are subtracted from the total mass of methane introduced into the detection chamber, so as to determine the mass of the first adsorbed methane in the shale at the pressure value, as shown in fig. 8 (fig. 8 is a schematic diagram of competitive adsorption information of carbon dioxide on methane in the shale at the same methane partial pressure provided by the embodiment of the present application).

Step 23) determining the mass of the second adsorbed methane in the shale in the detection chamber when the mixed gas of carbon dioxide and methane is introduced into the detection chamber of the NMR instrument.

Referring to fig. 1, the inside of the detection chamber is evacuated by a vent switch, methane in the shale powder is discharged, and the shale powder sample is dried in an oven (for example, for 24 hours and at a temperature of 90 ℃) and then is discharged to the detection chamber again. Further, after a mixed gas of carbon dioxide and methane (the volume ratio of carbon dioxide to methane is 1:1) with a pressure value of 2 × p0 was introduced into the detection chamber of the NMR instrument, second NMR information of methane (indicating a relationship between an NMR signal of methane in the detection chamber and a transverse relaxation time T2) was measured after the shale powder sufficiently adsorbed methane. Further, the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber are determined based on the second NMR information, the information on the relationship between the NMR signal and the mass of the free methane determined in step 12, and the information on the relationship between the NMR signal and the mass of the pore methane determined in step 14. And further, determining the mass of the second adsorbed methane in the shale in the detection chamber according to the total mass of the methane mixed with the carbon dioxide and introduced into the detection chamber, the mass of the second free methane in the shale and the mass of the second pore methane.

Illustratively, 0.2-4MPa of methane-carbon dioxide 1:1 mixed gas is respectively introduced into the detection chamber, and second NMR information of methane in the detection chamber corresponding to different pressure values as shown in fig. 9 (fig. 9 is a schematic diagram of second NMR information provided in an embodiment of the present application) is measured. As shown in fig. 9, as T2 changes from small to large, the NMR signal will show a first peak (representing an adsorbed methane binding peak), a second peak (representing a pore methane binding peak), and a third peak (representing a free methane binding peak) in that order.

Further, the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber under different pressure values are determined according to second NMR information corresponding to different pressure values. Further, for the condition of the methane-carbon dioxide 1:1 mixed gas at each pressure value introduced into the detection chamber, the mass of the second adsorbed methane in the shale in the detection chamber at the pressure value is determined according to the total mass of methane introduced into the detection chamber in a mixed manner with carbon dioxide, the mass of the second free methane in the shale at the pressure value, and the mass of the second pore methane, as shown in fig. 9.

Step 24) determines competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure.

By comparing the mass of the methane in the first adsorption state in the shale in the detection chamber when pure methane is introduced into the detection chamber of the NMR apparatus, which is determined in step 22, with the mass of the methane in the second adsorption state in the shale in the detection chamber when a mixed gas of carbon dioxide and methane is introduced into the detection chamber of the NMR apparatus, which is determined in step 23, competitive adsorption information of carbon dioxide to methane in the shale under the same methane partial pressure (for example, change information of the mass of methane in the adsorption state due to competitive adsorption of carbon dioxide, etc.) as shown in fig. 8 can be determined, so that efficient exploitation of shale gas can be reasonably guided.

Fig. 10 is a schematic structural diagram of a device for detecting competitive adsorption of carbon dioxide and methane in shale according to an embodiment of the present disclosure. As shown in fig. 10, the apparatus 100 for detecting competitive adsorption of carbon dioxide and methane in shale provided by the embodiment of the present application may include:

the first determining module 101 is configured to determine the mass of methane in a first adsorption state in shale in a detection chamber of a nuclear magnetic resonance NMR instrument after methane with a first pressure value is introduced into the detection chamber;

a second determining module 102, configured to determine the mass of the second adsorbed methane in the shale in the detection chamber after the mixed gas of carbon dioxide and methane with the pressure of the second pressure value is re-introduced into the detection chamber of the NMR instrument; wherein the volume ratio of the carbon dioxide to the methane is 1: 1; the second pressure value is 2 times of the first pressure value;

and a third determining module 103, configured to determine competitive adsorption information of carbon dioxide on methane in the shale under the same methane partial pressure according to the mass of the first adsorption state methane and the mass of the second adsorption state methane.

Optionally, the first determining module 101 includes:

and/or the second determination module comprises:

Optionally, the first determining unit is specifically configured to:

Optionally, the third determining unit is specifically configured to:

Optionally, the competitive adsorption detection apparatus 100 for carbon dioxide and methane in shale provided in the embodiment of the present application may further include:

and the acquisition module is used for acquiring the relation information between the NMR signal and the mass of the free methane and acquiring the relation information between the NMR signal and the mass of the pore methane.

Optionally, the obtaining module is specifically configured to:

determining a first volume of a detection chamber of the NMR instrument;

Optionally, the obtaining module is specifically configured to:

The competitive adsorption detection device of methane in carbon dioxide and shale that this embodiment provided can be used for the above-mentioned carbon dioxide of this application and the shale in the competitive adsorption detection method embodiment's of methane technical scheme, and its realization principle and technological effect are similar, and here is no longer repeated.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A competitive adsorption detection method for carbon dioxide and methane in shale is characterized by comprising the following steps:

2. The method of claim 1, wherein determining the mass of methane in the first adsorption state in the shale in the detection chamber of the Nuclear Magnetic Resonance (NMR) instrument after introducing pure methane at a first pressure value into the detection chamber comprises:

3. The method according to claim 1, wherein the determining the mass of the second adsorbed methane in the shale in the detection chamber of the NMR instrument after the mixed gas of carbon dioxide and methane at the second pressure value is re-introduced into the detection chamber comprises:

4. The method of claim 2, wherein determining the mass of the first free methane and the mass of the first pore state methane in the shale in the detection chamber from the first NMR information, the information on the relationship between NMR signal and mass of free methane, and the information on the relationship between NMR signal and mass of pore state methane comprises:

5. The method of claim 3, wherein determining the mass of the second free methane and the mass of the second pore methane in the shale in the detection chamber from the second NMR information, the information on the relationship between the NMR signal and the mass of the free methane, and the information on the relationship between the NMR signal and the mass of the pore methane comprises:

6. The method according to any one of claims 2-5, further comprising:

7. The method of claim 6, wherein the obtaining information about the relationship between NMR signal and mass of the free methane comprises:

determining a first volume of a detection chamber of the NMR instrument;

8. The method of claim 6, wherein the obtaining information on the relationship between the NMR signal and the mass of the methane in the pore state comprises:

9. The utility model provides a competition adsorption detection device of methane in carbon dioxide and shale which characterized in that includes:

10. The apparatus of claim 9, wherein the first determining module comprises:

and/or the second determination module comprises: