CN1091832C

CN1091832C - Method for disposing carbon dioxide in a coalbed and simutaneously recovering methane from the coalbed

Info

Publication number: CN1091832C
Application number: CN95190877A
Authority: CN
Inventors: 约瑟夫·J·切班克; 丹李; 小理查德·F·伏尔兹; 琼·P·塞德尔; 理杰恩·普瑞
Original assignee: BP Corp North America Inc
Current assignee: BP Corp North America Inc
Priority date: 1994-04-01
Filing date: 1995-03-24
Publication date: 2002-10-02
Anticipated expiration: 2015-03-24
Also published as: AU2193895A; CA2176588A1; CN1135782A; PL176443B1; PL316630A1; WO1995027123A1; CA2176588C; AU692248B2

Abstract

A method for treating a mixture of gaseous fluids within a solid carbonaceous subterranean formation. In some embodiments, the invention provides for the disposal of a strongly adsorbing gaseous fluid within the formation. In other embodiments, the invention provides a means for fractionating a mixture of gaseous fluids within the formation. In still other embodiments, the invention provides for the recovery of a raffinate from the formation which is enriched in relatively weaker adsorbing gaseous fluids. In still other embodiments, the invention provides for the recovery of methane from the formation.

Description

Be used for carbon dioxide is excreted to methane is also reclaimed in the coal seam simultaneously from the coal seam method

The present invention relates to performance, absorb gas in advance with the solid carbon subterranean strata, in order to the mist that separates in the stratum, and the method for the gas in the processing strong absorption stratum.

Contain various mists in the air-flow of many industrial treatment dischargings.People are concerned about that more and more the component of some effluent streams may cause great environmental problem, so these air-flows can not be discharged into the atmosphere.Carbon dioxide is a kind of component composition in a kind of many effluent streams that discharge from industrial treatment, and enters the attention that Atmospheric Carbon Dioxide is just causing that people are more and more high.

Suppose to enter Atmospheric Carbon Dioxide, will make global warming in case the greenhouse gases concentration in the atmosphere is too high as a kind of greenhouse gases.According to this possible sign, national governments have formulated or have planned the institution of regulations, to limit the amount of the carbon dioxide that can discharge into the atmosphere.These regulations can hinder many industry, and this is because the burning of arbitrary HC fuel and air can produce a kind of waste gas that contains carbon dioxide, nitrogen and other gas combustion thing.

The mist that causes hydro carbons and oxygen or air burning is called " waste gas " in the back.The chemical analysis of waste gas is decided by many factors, and these factors include but not limited to the hydro carbons that burns, the ratio of oxygen and fuel and ignition temperature in the combustion process.Outside removing carbon dioxide and the nitrogen, also may contain the compound that resembles carbon monoxide, sulfur oxide, nitrogen oxide and other component in the waste gas.These compounds of discharging into the atmosphere not only are subjected to the influence that the more public checks, but also are the objects that increases management rules.

Except being the hydrocarbon fuel product, also can produce carbon dioxide by natural process, and in non-combustion process, be discharged in the environment.For example, carbon dioxide is produced by heat and bioprocess, thinks that these processes have formed hydrocarbons, as oil, natural gas or coal.Usually produce carbon dioxide with these hydrocarbons, and it is discharged in the atmosphere through the procedure of processing of back.

The getable operable equipment that is used for removing the carbon dioxide of air-flow on several markets is arranged.One of most popular method is to use a kind of selectivity amine absorption liquid, and carbon dioxide is removed from air-flow.Regrettably this equipment will not allow bulky grain or sulfur oxide.Particle will cause the corrosion in obstruction, pollution and corrosion or the processing procedure, and simultaneous oxidation sulphur is as sulfur dioxide (SO ₂) with this method in employed amine aqueous solution generation irreversible reaction, thereby generate non-renewable byproduct.Therefore, if having particle or sulfur oxide, before from air-flow, removing carbon dioxide, need other processing step that sulfur oxide and particle are removed so.These extra processing steps have increased the complexity and the cost of this equipment.

Carbon dioxide and other compound to the release in the atmosphere more and more cause people's attention, need to handle the method for these compounds.Because these discarded compounds often are the components of the bigger effluent stream of partial volume, therefore best processing method is to manage to utilize bigger effluent stream to improve efficient in the whole process, and or use this method, except guaranteeing to handle the carbon dioxide that wherein contains, be convenient to reclaim value product.

(4November 1991 for SPE ASIA PACIFIC CONF PAPER NO.SPE 23026, PERTH, AUSTRALIA. Page743 M.D.STEVENSON ET AL. " Adsorption/desorption ofmulticomponent gas mixtures at inseam conditions ") relates to the adsorption and desorption method that a kind of mensuration contains the multicomponent mixture of carbon dioxide, nitrogen and methane.Its employed experimental facilities is a contactor, puts into this container after coal is broken, and then to the mixture of injecting carbon dioxide, nitrogen and methane wherein, and makes the interior coal of itself and container keep a kind of static balancing.

The invention provides a kind of employing KINETIC METHOD that is different from said method fully reclaims methane from the coal seam new method.

Preferably this method can be handled carbon dioxide, also can handle other impurity, does not handle other impurity and do not need to use a procedure to handle carbon dioxide and another road separation circuit step, as sulfur oxide and nitrogen oxide.

Just as used herein, following term has following implication:

(a) " adsorbate " is meant partially mixed gaseous fluid, and this gaseous fluid is preferentially adsorbed by the carbon containing mineral ore in the solid carbon subterranean strata, and when the gross pressure in the rock stratum descends, can reclaim this gaseous fluid from this rock stratum;

(b) " bedding " or " bedding system " is the natural system in crack in the solid carbon subterranean strata;

(c) " coal seam " comprises the coal seam of one or more fluid communication with each other;

(d) " desorb fluid " is to comprise any fluid or fluid-mixing, and described fluid can make methane desorb from the solid carbon subterranean strata;

(e) " formation fracture pressure " and " fracture pressure " means and opens the rock stratum and the pressure in the crack that expansion is induced in the rock stratum;

(f) " fracture half-length's degree " is the distance that records along the crack, the distance of promptly pushing up from the drilling well to the crack;

(g) " preferential adsorption ", " preferential sorption " and " preferential adsorption effect " refer to the process that takes place in the solid carbon subterranean strata, and this rock stratum changes the relative scale of gaseous fluid component.This process is by equilibrium separation, power separation, the three-dimensional separation, and/or the combination of any other physics or chemical process or these processes, can change the relative scale of gaseous fluid component, in the solid carbon subterranean strata, these processes will change the relative scale of fluid mixture component selectively.In the rock stratum, the gas that is adsorbed on the carbonaceous material in the rock stratum will be enriched in the stronger fluid-absorbent component;

(h) " raffinate " refers to the part gaseous fluid mixture that is injected in the hard carbon containing ground mantlerock, and it is not preferentially absorbed by the rock stratum;

(i) meaning of " recovery " is a kind of collection and/or processing of the fluid of controlling, as fluid storage is distributed through pipeline in jar or with fluid." recovery " particularly will cut off fluid and enter passage in the atmosphere;

(j) " reservoir pressure " meaning is in the shut-in well process, near the pressure of the production rock stratum well.Reservoir pressure can change by the rock stratum.In addition, the reservoir pressure in the rock stratum is injected in the rock stratum at the desorb fluid, and when producing fluid from this rock, can change in whole process.

(k) " solid carbon subterranean strata " refers to any hard basically carbon containing, contains the material of methane, and it is in below the face of land.Believe that these contain pyrolysis and the biodegradation of methane material by organic substance and can obtain.The solid carbon subterranean strata comprises, but is not limited only to resemble antrium, carbon containing and the stratum such carbon containing of Devonian system shale of coal seam and other.Stratum of the present invention comprises the stratum that callable methane is less.

(1) " absorption " refer to a process, comprising by carbonaceous material such as coal by this process gas, these carbonaceous materials have many micropores.The gas that is contained in the carbonaceous material micropore is condensation phase or liquid-like phase, and perhaps this gas can be attached on the carbonaceous material by chemical mode; With:

(m) " well spacing " or " spacing " is meant each producing well and injects distance between well, the individual well.This distance is to run through the local measured of valuable stratum in drilling well.

An object of the present invention is to provide a kind of method that is used in the solid carbon subterranean strata, separating gaseous fluid mixture.

Another object of the present invention provides a kind of method that is used for handling the fluid that is adsorbed on the solid carbon subterranean strata by force.

A further object of the invention provides a kind of method that is used for handling the carbon dioxide of solid carbon subterranean strata.

A further object of the invention provides a kind of carbon dioxide that is used for handling the solid carbon subterranean strata, reclaims the method for methane simultaneously from this rock stratum.

Another purpose of the present invention provides a kind of mist that contains strong fluid-absorbent and more weak fluid-absorbent that is used in the separating solids carbon containing subterranean strata, and is used to reclaim the method that is enriched in from the gaseous fluid on the more weak fluid-absorbent of rock stratum.

It is to utilize the gaseous fluid in the more weak fluid-absorbent of being enriched in reclaimed that the present invention also has another purpose, to improve the amount that reclaims methane from the solid carbon subterranean strata.

A further object of the invention is to provide a kind of method that is used to handle the bad gaseous fluid to the solid carbon subterranean strata of the callable methane of small part dilution.

A further object of the invention is to provide a kind of method that is used to handle the waste gas in the solid carbon subterranean strata.

Above-mentioned purpose of the present invention realizes by following aspects.

First aspect of the present invention is a kind of method of separating the gaseous fluid mixture in the coal seam, and this method comprises the following steps;

A) gaseous fluid mixture that will contain weak fluid-absorbent composition and strong fluid-absorbent component imports the coal seam; With:

B) from the coal seam, reclaim the raffinate that is enriched in the weak fluid-absorbent component.

In aspect second of the present invention, disclose a kind of being used for from the method by an injection well and the solid carbon subterranean strata recovery methane that producing well was penetrated into, this method comprises the following steps:

A) the desorb fluid that will have with the carbon dioxide of A equal volume percentage is injected into the solid carbon subterranean strata by injecting well;

B) from producing well, reclaim the fluid that comprises methane;

C) composition of the fluid that is produced in the detection step (b); With

D) when the volume ratio of the carbon dioxide in the fluid that is reclaimed in the step (b) during, then stop the fluid that is produced in the recycling step (b) greater than 0.5A.

In aspect the 3rd of the present invention, disclose a kind of being used for from the method by an injection well and the solid carbon subterranean strata recovery methane that producing well was penetrated into, this method comprises the following steps:

A) by injecting well, the desorb fluid that the volume ratio of other desorb fluid components of carbon dioxide that will have and injection equals B is injected into the solid carbon subterranean strata;

B) recovery contains the desorb fluid of injection to some extent and the fluid of methane from producing well;

C) inspection amount carbon dioxide and other injected is included in the percent by volume of the desorb fluid components of the fluid that producing well reclaims; With

D) reclaim when obtaining at least 70% methane greater than 0.5B with from producing well when the volume ratio of the component of the desorb fluid that carbon dioxide and other injected that in producing well, is reclaimed, stop from producing well, to reclaim fluid.

In a fourth aspect of the present invention, a kind of method that is used to handle the carbon dioxide in the solid carbon subterranean strata is disclosed, this method comprises the following steps:

A) percent by volume of the desorb fluid components that carbon dioxide and other injected that will the have fluid-absorbent that equals B is injected into the solid carbon subterranean strata;

B) percent by volume of the carbon dioxide that will have and other desorb fluid is extracted out from the rock stratum less than the gaseous fluid of B; With

C) when the volume ratio of the fluid-absorbent component that carbon dioxide and other injected in the gaseous fluid that step (b) is extracted out greater than 0.5 the time, stop from the rock stratum, to aspirate gaseous fluid.

In a fifth aspect of the present invention, disclosed is a kind of method that is used to handle the bad gaseous fluid component in the solid carbon subterranean strata, and this method comprises the following steps:

A) gaseous fluid that will contain bad gaseous fluid component imports the rock stratum, so that bad gaseous fluid component is adsorbed onto in the rock stratum; With

B) in the rock stratum, keep treatment conditions, so that the processing saturation ratio of guaranteeing to be adsorbed onto the bad gaseous fluid component in the rock stratum is at least 10%.

In a sixth aspect of the present invention, disclosed is a kind of method that is used to handle the bad gaseous fluid component in the coal seam, and this method comprises the following steps:

A) will contain in the gaseous fluid importing coal seam of bad gaseous fluid component; With

B) when the bad gaseous fluid component in the coal seam reaches certain saturation ratio, just stop gaseous fluid being imported in the coal seam.

In aspect the 7th of the present invention, disclosed is a kind of method that is used to handle bad gaseous fluid component, this method comprises the following steps: that the gaseous fluid that will contain bad gaseous fluid component imports in the coal seam, this coal seam lacks methane in treatment conditions down to small part, so that bad gaseous fluid component is adsorbed onto in the coal seam, and make the bad fluid components of discharging into the atmosphere reduce to minimum.

In certain aspects, the invention provides a kind of method that is used to handle a large amount of bad gaseous fluid component in the solid carbon subterranean strata.Some aspect allows the fluid resemble waste gas to be directed to the solid carbon subterranean strata, so that improve the amount that reclaims methane from the rock stratum, these waste gas can comprise nitrogen oxide, sulfur oxide, carbon monoxide and/or carbon dioxide.The present invention also provides a kind of effective ways that are used to produce the effluent stream that is rich in nitrogen, and this effluent stream that is rich in nitrogen can be used to improve the amount that reclaims methane from the solid carbon subterranean strata.Other schemes allow the fluid resemble waste gas to handle in the solid carbon subterranean strata, and do not need it and the system for handling that is used for carbon dioxide and sulfur oxide are separated.

Many other advantage and characteristics of the present invention will be from following detailed description of the present invention, and wherein described embodiment becomes clearer in claims and the accompanying drawing.

Fig. 1 is by gas total output and time relation curve map in the complete saturated coal seam of methane, has imported several different gas componants in this coal seam;

Fig. 2 is the cumulative methane curve map that prediction is reclaimed from the coal seam of Fig. 1;

Fig. 3 is a curve map of predicting the percent by volume of the methane that exists from the fluid that reclaim in the coal seam of Fig. 1;

Fig. 4 is a curve map of predicting the percent by volume of the nitrogen that exists from the fluid that reclaim in the coal seam of Fig. 1;

Fig. 5 is a curve map of predicting the percent by volume of the carbon dioxide that exists from the fluid that reclaim in the coal seam of Fig. 1;

Fig. 6 is the curve map that prediction is used for the methane recovery in Fig. 1 coal seam;

Fig. 7 is accumulation methane that reclaims and the graph of relation that is injected into the desorb fluid of the accumulation in Fig. 1 coal seam;

Fig. 8 is the curve map of the volume of the nitrogen that accumulation is reclaimed from the coal seam of methane dilution, and nitrogen is used to separate that to contain percent by volume be that 15% carbon dioxide and percent by volume are the mist of 85% nitrogen;

Fig. 9 is the gaseous fluid curve map of accumulation, and this gaseous fluid is injected in whole process in the coal seam of dilution of Fig. 8;

Figure 10 is the rate profile that reclaims nitrogen from the coal seam of the dilution of Fig. 8;

Figure 11 be from fully by total gas recovery rate and time relation curve map the saturated coal seam of methane, the total gas recovery rate when this figure is injected into the stratum with pure carbon dioxide and the rate of recovery when the mist of the methane of the percent by volume of the carbon dioxide that contains 70% percent by volume and 30% compare;

Figure 12 is a curve map of predicting the cumulative volume of the methane that reclaims from Figure 11 coal seam;

Figure 13 is a curve map of predicting the percent by volume of the methane that exists from the fluid that reclaim in the coal seam of Figure 11;

Figure 14 is a curve map of predicting the percent by volume of the carbon dioxide that exists from the fluid that reclaim in the coal seam of Figure 11;

Figure 15 is the curve map that prediction is used for the methane recovery in Figure 11 coal seam;

Figure 16 is the curve map that prediction is used for the recovery rate of CO 2 in Figure 11 coal seam;

Figure 17 is the curve map that is used for total gas production rates in Figure 11 coal seam;

Figure 18 predicts the methane of the accumulation of reclaiming and the graph of relation of the desorb fluid of the accumulation of being injected that is used for Figure 11 coal seam from the coal seam.

When the present invention can have many multi-form embodiments, accompanying drawing In demonstrate and will describe the present invention in detail, especially enforcement side of the present invention to be described Case. Certainly, this explanation is considered to an example of the present invention's design, but it can not Limit the present invention in the scope of embodiment of certain illustrated.

The solid carbon subterranean strata is to be made of carbonaceous material such as the coal seam. Carbon containing Material comprises parent rock, and this parent rock has micropore extension system and is penetrated in the parent rock Fault system, this fault system is commonly referred to as " bedding ". The micropore cording has bigger Inner surface, gaseous fluid can be attracted on the inner surface. The present invention utilizes each Plant gas molecule to the different adsorption strengths of carbonaceous material in the stratum, with a large amount of Good gaseous fluid is adsorbed onto in the micropore of carbon containing parent rock.

The gaseous fluid that injects

Usually, has the stronger gaseous fluid molecular proportion adsorption strength of adsorption strength Weak gaseous fluid molecular energy is adsorbed on the carbonaceous material in the stratum better. Inhale The amount that is attached to the gaseous fluid on the carbonaceous material in the stratum depends on gas to containing Ability, gas that the relative adsorption strength of carbon parent rock, carbonaceous material hold gaseous fluid Attitude fluid molecule and carbonaceous material generation chemical reaction and therefore chemisorbed to should Tendency on the material and the pressure and temperature in the rock stratum.

A key factor in the present invention's operation is the gaseous fluid that injects Relative adsorption strength between the component of mixture, and gaseous fluid mixture and its Its fluid is such as already present Adsorption of methane intensity in the rock stratum.

For the carbonaceous material resemble the coal seam, think the atmospheric boiling point of fluid Express the molecule of corresponding composition fluid or the adsorption strength of compound. Table 1 Listed the atmospheric boiling point of several frequently seen fluid.

Adsorption strength hydrogen (the H that table 1 compound/molecule boiling point is more weak₂)-269 ℃ helium (He)-253 ℃ nitrogen (N₂)-196 ℃ carbon monoxide (CO)-192 ℃ argons (Ar)-186 ℃ oxygen (O₂)-183 ℃ methane (CH₄)-162 ℃ nitrogen oxides (NO)-151 ℃ xenons (Xe)-108 ℃ ethane (C₂H ₆)-88 ℃ carbon dioxide (CO₂)-78 ℃ sulfur hexafluoride (SF₆)-64 ℃ hydrogen sulfide (H₂S)-60 ℃ propane (C₃H ₈)-42 ℃ sulfur dioxide (SO₂)-10 ℃ nitrogen dioxide (NO₂) 21 ℃ of stronger adsorption strength sulfur trioxide (SO₃) 44℃

It is generally acknowledged that stronger fluid-absorbent has higher boiling point, more weak absorption stream Body has relatively low boiling point. Therefore, in a kind of fluid components and the admixture of gas One other fluid relative adsorption strength and with the rock stratum in other gaseous fluid Relative adsorption strength, be to measure by relatively corresponding atmospheric boiling point. For example, carbon dioxide, its atmospheric boiling point are-78 ℃, and it is for the suction of carbonaceous material Attached strength ratio methane or sulfur dioxide are stronger, and the atmosphere of methane and sulfur dioxide boils Point is respectively-162 ℃ and-196 ℃. The atmospheric boiling point that a kind of fluid is corresponding will be given Those of ordinary skill provides the relative adsorption strength that relates to various gaseous fluids general Information. But for special carbonaceous material, various gaseous fluids are relative Adsorption strength is measured by rule of thumb in possible place.

In addition, the adsorption strength that various gaseous fluids are relative will be to those of ordinary skill Provide and relate to the general information of processing the bad gaseous fluid in the solid carbon rock stratum. But, just can measure by rule of thumb as possible and be adsorbed onto on the specific carbonaceous material The amount of bad gaseous fluid. Empirical data will allow to predict more accurately carbon containing ground The amount of bad gaseous fluid that can be processed in the lower rock stratum. If special gaseous state Be considered on the carbonaceous material of fluid components chemisorbed in the rock stratum important because of Plain, so when the amount of measuring the bad gaseous fluid in the processed rock stratum The time, also can calculate.

Gaseous fluid can import in the rock stratum when gaseous state or liquid state. The present invention couple The detailed description that is used for the suitable method of injection gaseous fluid can be lower from relating to The discussion of the raffinate of the injection enriched in nitrogen that face is discussed is learnt. Gaseous fluid is annotated Enter other the suitable method in the solid carbon subterranean strata, for common specialty The technical staff is known. If inject the liquid gas that contains carbon dioxide The attitude fluid will become gaseous fluid so usually in the rock stratum. In addition, can be with gas The attitude fluid imports the rock stratum as a kind of supercritical fluid. According to the pressure in the rock stratum and Temperature, gaseous fluid both can keep a kind of postcritical fluid, also can become Liquid, gaseous fluid or gas liquid mixture.

If the gaseous fluid that uses is near critical-temperature and the pressure, so just Must be with the deposition that makes solid in the rock stratum and liquid/or condense minimum method Exploit any producing well. How detailed hereafter exploits under such condition These producing wells.

From the rock stratum, reclaim methane

In the present embodiment, by the Injection Well that is communicated with formation fluid, will contain There is the desorb fluid of strong fluid-absorbent to import in the solid carbon subterranean strata, and From one or more producing wells, reclaim the fluid that contains methane. Injection Well is preferably worn Cross the rock stratum.

The desorb fluid is generally by carbon dioxide and other fluid components, as nitrogen and/or Methane forms. Because carbon dioxide is strong fluid-absorbent, thus it compared with other Weak fluid-absorbent, such as nitrogen or methane, the easier carbon containing that is adsorbed onto in the rock stratum On the material.

In the process of organic matter transformation coal-forming and other solid carbonaceous substance, produce Given birth to methane. Methane in the rock stratum is both as being free in the bedding and crack of rock stratum Gas, also as the adsorbed gas in the parent rock of rock stratum.

The desorb fluid that contains carbon dioxide makes methane and absorption free in the rock stratum Methane flow. Because the decline of the dividing potential drop in the bedding and because carbon dioxide and its The desorb fluid that it injects falls over each other to be adsorbed on the carbon containing parent rock of rock stratum, thereby makes suction The methane that is attached on the carbon containing parent rock flows.

The branch drops of methane is because the desorb fluid that injects in the crack in the crack Near the methane absorption position. When the branch drops of methane in the crack, be adsorbed on and contain Methane on the carbon parent rock will desorb from the crack, and is distributed in the bedding.

The desorb fluid of carbon dioxide and other injection falls over each other to be adsorbed on the carbon containing parent rock On, will cause that methane desorb from the carbon containing parent rock enters into bedding. In case methane Be in the bedding pressure that improves between rock stratum and producing well and/or the well so Gradient will make methane move in the well that producing well maybe can reclaim.

Because not resembling, methane is not adsorbed on consumingly on the carbon containing parent rock the carbon dioxide, So passing the stronger adsorbed gas of the velocity ratio of solid subterranean strata, methane flows Hurry up.

Strong fluid-absorbent in the carbon containing parent rock in the rock stratum, excellent such as carbon dioxide Elder generation's suction-operated makes desorb fluid fractionation in the rock stratum of injection. Stronger absorption Fluid will be preferentially adsorbed to the zone of Injection Well carbon containing parent rock on every side, this injection Injected the desorb fluid in the well. Stronger fluid-absorbent will continue to be adsorbed on this zone In parent rock on, until stronger fluid-absorbent is saturated on the parent rock. Relatively Weak fluid-absorbent will not be adsorbed onto on the parent rock like that doughtily, thereby it passes the rock stratum The more intense fluid-absorbent of speed want fast.

When the desorb fluid was injected in the rock stratum usually, strong fluid-absorbent reached in the rock stratum To continue towards the future development of producing well or well to saturated zone. Therefore, can To say that strong fluid-absorbent will form the gathering face that develops that approaches in the rock stratum. Work as solution When inhaling fluid and being injected in the rock stratum, in gathering face will continue from Injection Well to the rock stratum Lower pressure region is extended such as the direction of producing well.

In the front of face, be adsorbed on the concentration specific surface of the strong fluid-absorbent on the parent rock Inside or the concentration of the strong fluid-absorbent of the back of face little. Behind face Face is adsorbed on the strong fluid-absorbent on the parent rock, and is approaching such as the concentration of carbon dioxide A stationary value, this is because the desorb fluid is injected continuously by Injection Well In the rock stratum.

Stationary value depends on several factors, and these factors comprise: strong fluid-absorbent To the relative adsorption strength of carbon containing parent rock, with the absorption of other fluid in the rock stratum The comparison of intensity; With contained the inhaling more by force in the desorb fluid that is injected in the rock stratum The relative concentration of attached fluid.

Because strong fluid-absorbent component will preferentially be adsorbed by the rock stratum, so contain The desorb fluid of carbon dioxide can be injected into the solid carbon subterranean strata, simultaneously from Producing well reclaims the fluid with lower carbon dioxide percent by volume. Sometimes gas The percent by volume of the carbon dioxide in the attitude fluid mixture is called as body in the back Long-pending percentage A.

In addition, because the more weak suction of velocity ratio that strong fluid-absorbent component is passed the rock stratum Attached intensity fluid components is slow, can reclaim fluid from producing well, the dioxy in it Change the ratio of carbon and the volume of the desorb fluid components of other injection, less than carbon dioxide Body with the fluid components of other injection in the desorb fluid that is injected in the rock stratum Long-pending ratio. The ratio of carbon dioxide and the desorb fluid components volume of other injection after Face is called as ratio B sometimes.

Contain in the present invention a kind of carbon dioxide of operable gaseous fluid Waste gas. Usually other desorb fluid components that injects in carbon dioxide and the waste gas The ratio of volume is 1/11 to 2/8. Contain and in the present invention operablely contain two Another example of the gaseous fluid of carbonoxide is the mixture of gaseous fluid, this gaseous state The mixture of fluid is by nitrogen injection device or membrane separator injection, described separator Carbon dioxide is separated from natural gas product stream. Common in the air-flow of injection The ratio B from 1/1 to 95/5 that contains carbon dioxide and methane and other gas.

Think in the fluid that from producing well, reclaims the volume percentage of carbon dioxide Carbon dioxide than the desorb fluid that will be lower than the injection in being input to the rock stratum Percent by volume, until the rock stratum between Injection Well and the producing well with more by force absorption Till fluid components is saturated. In addition, think carbon dioxide with from producing well, reclaim Fluid in the percent by volume of desorb fluid components of contained other injection with low In carbon dioxide and the solution that is input to other injection in the desorb fluid in the rock stratum Inhale the percent by volume of fluid components, until the rock stratum of injecting between the producing well is used Strong fluid-absorbent component is saturated.

In ideal conditions, the solid carbon subterranean strata is uniformly, and two Carbonoxide enrichment face will be promptly inner mobile from Injection Well to the rock stratum. But, very There is less so uniform solid carbon subterranean strata. Most rock stratum is to inject The zone that the desorb fluid can pass rapidly. These so-called " mineral ores " comprise with mainly Carbonaceous material is compared has relatively high infiltrative zone. Mineral ore also comprises by solution Inhale the zone that material consisted of that fluid components can not be adsorbed rapidly. For example can not The mineral ore zone of fluid-absorbent comprises sandstone, contains carbon shale and common specialty rapidly Other similar substance known to the technical staff.

The desorb fluid that passes mineral ore that injects partly passes through the rock stratum to the major general In carbonaceous material, and to be said to be towards " ore bed " of producing well in the rock stratum. Should Ore bed will improve existing desorb fluid in the fluid that reclaims from producing well Relative quantity.

In addition, pass the desorb fluid that injects that mineral ore arrives producing well, can not Resemble the desorb fluid that injects that does not pass mineral ore and the carbon containing of rock stratum The material contact. So, pass the desorb fluid that injects that mineral ore arrives producing well Component can not be divided into their components separately like that effectively. Therefore, dioxy The desorb fluid group of other injection in the fluid of changing carbon and from producing well, reclaiming The percent by volume of dividing will bring up to ratio desired in desirable rock stratum with On, but the contained original ratio of the desorb fluid that this ratio will inject relatively is still lower Fallen.

The preferential adsorption effect of the strong fluid-absorbent component in the rock stratum is to allow Strong fluid-absorbent is processed described stronger suction in the rock stratum such as carbon dioxide Attached effect makes the weak fluid-absorbent component of strong fluid-absorbent Component comparison more lentamente Pass the rock stratum. Be discussed in detail below for the treatment of two in the solid carbon subterranean strata The method of carbonoxide and other strong fluid-absorbent.

The solid carbon subterranean strata separates the ability of injecting the desorb fluid, and is namely most of The time of carbon dioxide arrival producing well and/or well will be later than more weak adsorption capacity Methane and/or other fluid will provide a kind of for from the solid carbon subterranean strata Reclaim most methane, process simultaneously the method for carbon dioxide in the rock stratum.

When implementing the method, in producing well and/or well ordinary skill institute The method of knowing is measured in carbon dioxide and the fluid that reclaims such as gas chromatography The ratio of desorb fluid of other injection. This mensuration will illustrate the solution of injecting Inhale how fluid moves and whether the rock stratum has been in strong fluid-absorbent in the rock stratum Saturation state.

As noted earlier, carbon dioxide is with from the fluid that producing well reclaims The ratio of the desorb fluid components of other injection, with respect to carbon dioxide be input to The solution of other injection in the desorb fluid of the injection in the solid carbon subterranean strata The ratio of inhaling fluid components will descend.

When in case the carbon dioxide face arrives the well head of producing well, carbon dioxide with from life The ratio of the desorb fluid components of other injection that the product well reclaims will promptly be carried High. Referring to the example shown in Fig. 4,5,13 and 14. In case carbon dioxide enriched (be the edge in the rock stratum between Injection Well and the producing well from Injection Well through producing well The carbon containing parent rock of the flow channel of desorb fluid, swept across contained methane), that Usually be adsorbed on and between Injection Well and producing well, inject the desorb Fluid Flow in A Most methane in the carbon containing parent rock of passage will desorb from the rock stratum.

Still as previously mentioned, actual solid carbon subterranean strata contains and can improve from life The mineral ore of the desorb fluid volume percentage in the fluid that the product well reclaims. In addition, Because mineral ore just can increase the amount of the needed injection desorb in inswept rock stratum fluid.

The inventor thinks can reduce in the rock stratum one of the mineral ore amount that produces effectively Kind method, the method are used intermittently, and the injection effect is injected into injection with fluid such as water In the well. The water that injects will enter higher permeability zones selectively. In case stream Body enters higher permeability zones, and it will reduce the desorb flow and cross these so The speed in zone. This will be so that the desorb fluid that injects changes its course enters than hypotonicity The zone, thus the inswept of vertical and surface in the rock stratum improved. Owing to inject The desorb fluid changes its course and enters the hyposmosis zone, so the desorb fluid moves from Injection Well Arrived the time lengthening of producing well. Again because the injection desorb fluid that changes its course is passable Contact with the more carbonaceous material in the rock stratum, reclaim so can reduce from producing well Fluid in the percent by volume of carbon dioxide and carbon dioxide and from producing well The ratio of the desorb fluid components of other injection in the fluid that reclaims.

Whether stop from producing well, to reclaim fluid, depend in part on from the rock stratum and return Receive, by the percentage of the methane of discharging in the producing well. The methane that obtains like this is can With the methane that from producing well, reclaims. It should be noted that through strengthening enrichment and return Dilution can not take place in the methane in the rock stratum of receiving, and from special producing well To methane dilution may take place. Methane content in the solid carbon subterranean strata can Measure with the method known to the those of ordinary skill. Methane contains in the computing formation The method of amount is being published by AAPG 1993, in the coal Hydrocarbon compound, chapter 9, the 203-207 page or leaf, the people such as Yee " inhale by the gas of coal The mensuration of attached effect and gas content " in set forth, it is as a reference and quilt Introduce. Know what methane content contained in the rock stratum and injection desorb fluid formed Those of ordinary skill can calculate the content that reclaims methane from the rock stratum.

Whether continue from producing well, to reclaim fluid and will consider the fluid value. Measuring should During the fluid value, importantly to consider further to utilize the needed technology of flow Cost. For example, if fluid is delivered to natural gas line, fluid must be located Reason is in order to make the percentage of its inner inert gas be reduced to receivable water Flat. The reception level of contained inert gas is to be stipulated by gas pipeline in the natural gas Control. If Fluid Volume is not how must be enough to think that further recovery is worthwhile , so the recovery of fluid will stop or amending method so that fluid form is become Become to think that further recovery is worthwhile stage.

The methane of solid carbon subterranean strata can have several notes on stream Enter well and several producing well. Because most solid carbon subterranean stratas is inhomogeneous Property can be from second notes from carbon dioxide enriched of an Injection Well The carbon dioxide enriched face that enters well reaches and reaches production in the same producing well in the past Well. This will cause carbon dioxide and other injection from the fluid that producing well reclaims The increase of ratio of desorb fluid components, the rock between Injection Well and producing well Before the cleaning of the available methane of layer, approach or surpass original ratio B.

As can from Fig. 2,3,5-7 and 11-15 see, at dioxy Change the desorb fluid components of carbon and other injection from the fluid that producing well reclaims Ratio reach before original ratio B, can from the rock stratum, reclaim and to obtain methane Actual percentage. When ratio B be original ratio B 0.5 to 0.9 the time, think Preferably stop in some cases from producing well, reclaiming waste gas. For example, work as dioxy The ratio of the desorb fluid components of other injection is low in the fluid of changing carbon and reclaiming In B, but from producing well, reclaimed the actual percentage of available methane The time, preferably will stop from producing well, to reclaim fluid.

If carbon dioxide and other injection from the fluid that producing well reclaims The ratio of desorb fluid components is greater than original ratio B, and output from this well The actual ratio of available methane, preferably stop from producing well, to reclaim Fluid.

If carbon dioxide and other injection from the fluid that producing well reclaims The ratio of desorb fluid components is greater than original ratio B, but exists from producing well still But in the situation of the actual percentage of output methane, preferably will not stop from producing well The middle fluid that reclaims. And will be restricted from the flow in the producing well.

From the mobile pressure that will increase in the well that is restricted in the producing well. Give birth to The increase of producing the pressure around the well will cause that the desorb fluid of injection changes its course and enter In the lower rock stratum of pressure. This restriction will be conducive to improve the rock stratum exhaust and Reduced the injection desorb fluid towards the producing well that is subjected to flow restriction. In addition, By increasing producing well rock pressure on every side, it is preferential just can to strengthen carbon dioxide In the effective suction-operated of methane to the carbon containing parent rock. Think that this will reduce from producing well The percent by volume of institute's carbonated in the middle fluid that reclaims.

Can limit the fluid that from producing well, flows out with several method. A kind of Method is to use will to suppress stream material and be injected near near the carbon containing of producing well The rock stratum, logistics is expected to be suppressed in the producing well. For example be used for suppressing from producing well The material of the fluid that flows out comprises such as carbon dioxide, acetone, pyridene diesel oil, poly-Compound, epoxy resin, surfactant, foam, cement and their mixture. On State material owing to stop up or solidify splitting in the rock stratum and be, thereby reduced in the rock stratum Flowing of suppression fluid, thus the infiltration in affected zone, rock stratum reduced The property. Except above-mentioned material, carbonaceous material is expanded and its permeability is reduced or Any material that Fracture System is clogged or solidify all will be to use.

The another kind of limit fluid that is used for comprises with a kind of from the method that producing well flows out The method that restriction waste gas flows out from producing well is controlled one and producing well fluid company Logical valve. Owing to adopted above-mentioned technology, the fluid that restriction is flowed out from producing well To near the borehole pressure the rock stratum be risen, and reached above-mentioned advantage, this A little advantages are considered to cause near the factor of the borehole pressure rising of producing well.

Said method will help to keep available methane in the recyclable producing well.

Any carbon dioxide that together reclaims with fluid can be promptly with fluid in Methane and other fluid separate such as nitrogen. A kind of carbon dioxide is separated with flow Method comprise:

With membrane separator carbon dioxide is separated with admixture of gas;

Use the absorption type separator, as pressure rotation adsorbing separation device with carbon dioxide with Admixture of gas separates; With

With the nitrogen injection device with carbon dioxide and admixture of gas freezing separation.

Comprise that the fluid carbon dioxide that said method produces generally also contains methane and/or nitrogen.If desired, the carbonated air-flow can be injected in the solid carbon subterranean strata.

The inventor has been found that in some cases, can continue to reclaim from producing well fluid, and most fluid stream returned is recycled in the rock stratum.For example favorable environment is the place of reclaiming a large amount of obtainable methane from producing well, but the percentage of the carbon dioxide in the air-flow is higher.In this case, with inert gas, may be too high with traditional separator as the cost of carbon dioxide and nitrogen and methane separation.

In these cases, the inventor discloses and may more help using fluid air flow to improve the methane that is reclaimed from the zones of different of another solid carbon subterranean strata or same solid carbon subterranean strata.Preferably, a large amount of carbon dioxide still can be adsorbed in the rock stratum of having injected fluid.

By the rock stratum air-flow that re-injects is separated.Carbon dioxide contained in the air-flow that re-injects will pass rock movement to producing well more lentamente.As noted earlier, carbon dioxide will be replaced the methane in the rock stratum.Contained methane will pass the rock stratum apace and reach producing well in the air-flow that re-injects.Think that contained methane in the stream that will re-inject will help to keep the storage pressure in the rock stratum, thereby help from the rock stratum, to reclaim methane.Figure 11 to 18 has represented in these cases how the mist that contains methane and carbon dioxide is used to reclaim the methane in the solid carbon subterranean strata.

The processing of gaseous fluid

In this embodiment, the gaseous fluid that will contain bad gaseous fluid component is injected in the solid carbon subterranean strata.By an injection well that is communicated with formation fluid, preferably pass the injection well of rock stratum, gaseous fluid is injected in the solid carbon subterranean strata.Under the storage pressure in being higher than the rock stratum, gaseous fluid is injected in the rock stratum, and can under gaseous state or liquid state, gaseous fluid be injected in the rock stratum.Preferably, be to inject gaseous fluid under the rock stratum dividing potential drop in being lower than the rock stratum.If the too high and rock breakdown of pressure that injects, the gaseous fluid of Zhu Ruing just may leak into rock stratum on every side from the solid carbon subterranean strata so.

Generally contain carbon dioxide and/or other gaseous fluid component in the described gaseous fluid, the ability that they are adsorbed onto on the carbonaceous material is more eager to excel in whatever one does than methane.For example generally be contained in other gaseous fluid component of injecting gaseous fluid and comprise sulfur oxide, nitrogen oxide and hydrogen sulfide.These relatively strong adsorbed gases preferentially are adsorbed onto on the carbonaceous material in the rock stratum than any methane in the rock stratum.

Waste gas is a kind of in the handled gaseous fluid of the present invention.Waste gas generally contains the nitrogen of the carbon dioxide of 10-25% percent by volume, about 75-90% percent by volume and the nitrogen oxide and the sulfur oxide of a little volume percentage.The separator that the mixture that the operable another kind of gaseous fluid of the present invention is a gaseous fluid, this usefulness make carbon dioxide separate with natural gas product stream injects.Inject the carbon dioxide that stream contains the 50-95% percent by volume of having an appointment, remaining gaseous fluid mainly is made of methane.Inject stream and also may contain hydrogen sulfide, nitrogen oxide and sulfur oxide.

According to this embodiment, handle the used solid carbon subterranean strata of bad gaseous fluid component and contain callable methane more better.Use contains the few rock stratum of recyclable methane, is because be adsorbed onto fluid on the carbon containing parent rock in the rock stratum, is enhanced as the suction-operated preferably of carbon dioxide, and the methane concentration that is adsorbed in the described rock stratum on the carbon containing parent rock is lower.In addition, if the pressure in the rock stratum descends, callable methane is less in the rock stratum, can handle a large amount of weak gaseous fluids of ratio methane absorption so in the rock stratum effectively.

In other cases, the solid carbon subterranean strata of methane is never produced in preferred use.From such rock stratum, produce methane and do not have attraction.Such rock stratum comprises the rock stratum that original methane content is lower and the rock stratum of hypotonicity.

The rock stratum that contains callable methane exhaustion still contains some methane, but the concentration of this methane does not have the economic worth that reclaims it.The original methane that contains existing at least 25% percent by volume in the less rock stratum of callable methane is removed from the rock stratum.Containing the basic exhausted rock stratum of callable methane has the original methane of at least 50% percent by volume to remove from the rock stratum.Containing the exhausted fully rock stratum of callable methane has the original methane of at least 70% percent by volume to remove from the rock stratum.

A kind of method that reclaims methane from the rock stratum is to utilize the pressure in the rock stratum to descend.The reduction of the pressure in the rock stratum will make methane desorb from carbonaceous material, and flow in the recoverable producing well.When the original methane that reclaims is that 25%-is about 70% the time, utilize mainly and reduce, from producing well, produce the coal seam of methane and abandoned usually.For the pressure of abandoning of this well that exhausts substantially generally 689,476 Pascals (Pa) to about 2,068,427 Pascals (Pa).

Utilize the raising recovery technology also can from the coal seam, reclaim methane.The example of a raising recovery technology that can effectively methane be reclaimed from the coal seam is to utilize the nitrogen rich stream that methane is desorbed from the coal seam.Use nitrogen to improve recovery technology for the coal seam, the percentage that reclaims methane from the coal seam depends primarily on the percent by volume that contains nitrogen from the coal seam in the product stream that reclaims.When the percentage of Tai Gao and/or methane became too low can't further the recovery in case the percentage of common nitrogen becomes, described producing well generally will be abandoned.According to present nitrogen/methane separation technology, when the methane percent by volume in the fluid that reclaims from the rock stratum is that 25%-is about 50% the time, producing well generally will be abandoned.This is corresponding with recovery 45%-about 70% original methane in the rock stratum.It should be noted that when methane and nitrogen isolation technics are developed the amount that reclaims methane from the rock stratum will increase.Improve from the rock stratum when reclaiming methane with nitrogen when the rock stratum, preferably before the bad gaseous fluid in handling the coal seam, reduce the pressure in the rock stratum.

Another can improve from the recovery technology of solid carbon subterranean strata recovery methane effectively is the recovery that carbon dioxide improves, and this technology was described in detail in the above.

As noted earlier, strong fluid-absorbent is than relative more weak fluid-absorbent, and is stronger to the adsorption capacity in carbon containing parent rock zone around the injection well.Strong fluid-absorbent is with on the parent rock that continues to be adsorbed in this zone, till this parent rock is saturated by strong fluid-absorbent.Relative more weak fluid-absorbent can not be adsorbed on the parent rock like that doughtily in the rock stratum, and flows in the rock stratum of lower pressure region.In a word, when gas is injected in the rock stratum, has been full of than the zone in the rock stratum of strong fluid-absorbent and has continued to enlarge away from injecting well.

In the rock stratum on the carbonaceous material, the saturation ratio of any gaseous fluid component depends on Several Factors, it comprises the comparison of strong fluid-absorbent to the adsorption strength of other fluid in the relative adsorption strength of carbon containing parent rock and the rock stratum, be input in the rock stratum inject the relative concentration that gaseous fluid includes strong fluid-absorbent, be used to adsorb common pressure and temperature in the ability that contains material of specific gaseous fluid component and the rock stratum.

For example, it is few to contain methane in a kind of common San Juan Fruitland rock stratum coal, when this coal reaches the gas saturation of nitrogen of the carbon dioxide that contains 85% percent by volume and 15% percent by volume, at pressure is 10,342 Pascals and temperature are under 46.1 ℃, and every kilogram of coal will adsorb the gas of about 0.0246 standard cubic meter (SCM).The adsorbed carbon dioxide of about 99% percent by volume and the nitrogen of about 1% percent by volume of will comprising mutually on the coal.When this coal reaches the gas saturation of nitrogen of the carbon dioxide that contains 50% percent by volume and 50% percent by volume, under uniform temp and pressure, every kilogram of coal will adsorb the gas of about 0.0219 standard cubic meter (SCM).Absorption will comprise the carbon dioxide of about 93% percent by volume and the nitrogen of about 7% percent by volume mutually.Under uniform temp and pressure, gas for the nitrogen of carbon dioxide that contains 15% percent by volume and 85% percent by volume, every kilogram of coal will adsorb the gas of about 0.0153 standard cubic meter (SCM), and absorption is by the carbon dioxide of about 70% percent by volume and the nitrogen of about 30% percent by volume.Under uniform temp and pressure, methane for carbon dioxide that contains 70% percent by volume and 30% percent by volume, every kilogram of coal will adsorb the gas of about 0.0233 standard cubic meter (SCM), and absorption comprises the carbon dioxide of about 86% percent by volume and the methane of about 14% percent by volume mutually.Absorption is made up of the carbon dioxide of about 70% percent by volume and the nitrogen of about 30% percent by volume.Drawing the aforementioned calculation saturation ratio is can obtain unrestricted a large amount of gaseous fluid and pass through Continuous Selection at the supposition coal, and weak fluid-absorbent component continues to flow and replaced by fresh gaseous fluid.So that other stronger adsorptive gaseous fluid components can preferentially be adsorbed on the coal.The strong fluid-absorbent of enrichment is to occur in adsorbing result preferential in the solid carbon subterranean strata in the absorption mutually.The coal that methane almost exhausts is relevant with the coal seam that the original methane that still keeps below about 10% percent by volume in the coal seam is arranged.

The special bad gaseous fluid component of listing above is called as " processing saturation ratio " afterwards.According to the temperature and pressure that provides, calculate the saturation ratio of the processing that is used for special bad gaseous fluid component.Temperature and pressure and be used for handling employed other the running parameter of bad gaseous fluid component in the rock stratum and be called as treatment conditions.Controlling these conditions can make a large amount of bad gaseous fluid components be adsorbed onto on the rock stratum.General treatment conditions are such so that can handle the bad gaseous fluid component that 10% to 90% percent by volume is imported in the rock stratum.In some instances, think and in the rock stratum, can handle the bad gaseous fluid component that is higher than 99% percent by volume.By the bad gaseous fluid component of processing in the rock stratum, thereby prevented that bad gaseous fluid component is released in the atmosphere.Keep these treatment conditions generally only to need to close and/or control fluid passage, discharge into the atmosphere from the rock stratum, keep pressure in the rock stratum to be lower than the dividing potential drop of rock stratum simultaneously to prevent bad gaseous fluid component from the rock stratum.The ability of adsorbing in some instances, bad gaseous fluid component termly to the rock stratum dehydration with maintenance or enhancing rock stratum.In some instances, the associated temperature that improves in the rock stratum is useful.If for example improved the temperature in the rock stratum then chemical reaction takes place for bad gaseous fluid component and rock stratum, and this will become more favourable when being reflected at the temperature rising rock stratum in.

For given solid carbon subterranean strata, be used for special bad gaseous fluid component the processing saturation ratio can by lengthening Langmuir absorption isotherm model and the necessary data in the rock stratum of giving calculate.The explanation of lengthening Langmuir absorption isotherm model and how to utilize it to produce model like the employed model class of the inventor, be disclosed in people's such as L.E.Arri, publish in (1992) " foundation has the coal bed methane output of binary gas absorption " SPE 24363, the 459-472 pages or leaves by Petroleum Engineer association; Here be introduced into as a reference.

Think and just can consequently can in the rock stratum, import more strong absorbed component in the solid carbon subterranean strata so from the rock stratum near the saturation ratio of handling if a method that relative more weak fluid-absorbent is removed is arranged.This additional strong absorbed component will continue to be adsorbed on the rock stratum, in parent rock absorption mutually near till the processing saturation ratio.A kind of method of will more weak absorbed component removing from the rock stratum is the gap or unceasingly more weak fluid-absorbent is discharged from the rock stratum.Another kind of method of will more weak absorbed component removing from the rock stratum will be from reclaiming these more weak fluid-absorbent by producing well.Think that in use of the present invention the rock stratum has been full of bad gaseous fluid component and has reached 10%-99% processing saturation ratio; Preferably reach 50%-95% and handle saturation ratio; More preferably reach 70%-90% and handle saturation ratio.

In a word, the pressure of the present invention's use is chosen such that to cause bad gaseous fluid component best to the suction-operated of the carbon containing parent rock in the rock stratum.Normally used pressure is higher, and the gas that is adsorbed by the carbon containing parent rock just the more.

When gaseous fluid was imported into the solid carbon subterranean strata, the ratio of the gaseous fluid of the position of the bad gaseous fluid component in the rock stratum, the relative concentration of the bad gaseous fluid component in the rock stratum and bad gaseous fluid component and other injection preferably can be measured.A kind of method of measuring this rock stratum is to obtain fluid sample from measuring well.With the method that ordinary skill is known, analyze this sample as gas chromatograph.This measurement will relative to illustrate how in the rock stratum, to move the gaseous fluid that is injected into and rock stratum by the bad air component saturated degree.

If bad gaseous fluid component is a kind of gaseous fluid component stronger fluid-absorbent relatively of the injection than other, the percent by volume of the gaseous fluid component of bad gaseous fluid component and other injection in the waste gas that is extracted in the measuring instrument so, the percent by volume of the gaseous fluid component of bad gaseous fluid component and other injection has reduced in the gaseous fluid with respect to the injection that is input to the solid carbon subterranean strata.

Thinking the decline of ratio of gaseous fluid component of bad gaseous fluid component and other injection, is the strong fluid-absorbent component in the carbon containing parent rock in the rock stratum, has suction-operated preferably as titanium dioxide and causes.Think that this suction-operated will cause that the more weak fluid-absorbent component of velocity ratio that moves relative to strong fluid-absorbent component is slow in the rock stratum.As noted earlier, when gaseous fluid was input in the rock stratum, the zone that is full of strong fluid-absorbent in the rock stratum outwards enlarged on away from the direction of injecting well.Strong fluid-absorbent is solidified, near the enrichment face that raises in the rock stratum.When gaseous fluid was input in the rock stratum, enrichment face flowed continuously from injecting well low-pressure area in the rock stratum.Inspissation of the fluid with other injection fluid that is extracted will continue, till enrichment face arrives measuring well.

In case during the formation area that enrichment face arrival measuring instrument well array goes out, the ratio of the gaseous fluid component of the injection of other that collect in bad gaseous fluid component and the measuring well will increase sharply.Because most hard complexity that contain subterranean strata can make bad gaseous fluid component irregular motion in the rock stratum.Can make the maldistribution of bad gaseous fluid component in the rock stratum like this.Therefore help using more than one well to measure the rock stratum.

In one aspect of the invention, import the bad gaseous fluid component of gaseous fluid in the rock stratum continuously and be saturated to certain degree.The waste gas sample of those of ordinary skill by obtaining from the measuring well through formation area can be measured the saturation ratio of individual areas in the rock stratum.

The chemical composition of the sample that obtains and the pressure information that relates near the rock stratum of close measuring well can be measured those of ordinary skill and are adsorbed on each interior gaseous component of carbon containing parent rock in the formation area of the sample that obtains.Whether the bad gaseous fluid component of gaseous fluid that makes those of ordinary skill can measure injection has like this arrived the zone of the sample that obtains.Also can make those of ordinary skill can measure the saturation ratio that bad gaseous fluid component is full of formation area.Required saturation ratio relates in the above and has done all-side introduction in the explanation of handling saturation ratio in the rock stratum.

As noted earlier,, get rid of the rock stratum a large amount of bad gaseous fluid components will be adsorbed onto in the rock stratum of any given processing pressure if bad gaseous fluid component is a kind of relatively strong fluid-absorbent.This eliminating occur in pass any one with well that the rock stratum is communicated with in.If you are using, eliminating can be carried out off and on or continuously, and it occurs in the injection of gaseous fluid and carry out synchronously, or carries out after stopping to inject gaseous fluid.

If the gaseous fluid component is removed as hydrogen sulfide, sulfur oxide and nitrogen oxide, can help to reduce the pressure in the rock stratum, so that from the rock stratum, carbon dioxide is desorbed fully.But deficiency so that hydrogen sulfide, nitrogen oxide and sulfur oxide from the carbon containing parent rock, desorb.This eliminating in the rock stratum will make a large amount of strong adsorbing compositions, be removed in hydrogen sulfide and some nitrogen oxides and sulphur are in the rock stratum.

Gaseous fluid can be injected in the rock stratum off and on or continuously.Gaseous fluid generally injects continuously till reaching required pressure.After the amount with required gaseous fluid is input in the rock stratum, or the rock stratum has reached after the required pressure, inject well and be shut-in well, and the rock stratum preferably remains under the sufficient treatment conditions, maintain 40%-80% so that will be adsorbed on the percent by volume of the bad gaseous fluid component on the rock stratum; Be preferably in gaseous fluid and be injected into after the solid carbon subterranean strata, the bad gaseous fluid component that is adsorbed on the rock stratum was kept 1 year at least.

In addition, the bad gaseous fluid in the rock stratum reaches after certain saturation ratio, just stops method of the present invention.In using process of the present invention, generally allow to be injected into percent by volume in the rock stratum and be lower than 50% bad gaseous fluid component and enter atmosphere; Better be to be lower than 10%; Preferably be lower than 1%.Bad gaseous fluid component generally remains at least one year in the rock stratum; Better be to keep 5 years; Preferably kept 10 years.

The separation of gaseous fluid mixture

In another embodiment of the present invention, contain the gaseous fluid mixture of strong relatively fluid-absorbent component and relative more weak fluid-absorbent component, be injected into the solid carbon subterranean strata by the injection well that is communicated with formation fluid.Strong fluid-absorbent component in the mist will be preferentially adsorbed on the carbon containing parent rock in the rock stratum.The strong fluid-absorbent of utilization of the present invention provides a kind of first that is enriched on the more weak fluid-absorbent and second portion that is enriched on the strong fluid-absorbent that mist is divided into to the preferential suction-operated of rock stratum.The example of the gaseous fluid mixture that can separate includes, but are not limited to: air, waste gas, the mist that produces from various industrial production and mist from getting rid of nonflammable gaseous fluid and compressible liquid and the separator that natural gas product stream separates.

In this embodiment of the present invention, gaseous fluid mixture is injected into the solid carbon subterranean strata through the injection well that is penetrated in the rock stratum usually.Preferably this rock stratum has not had callable methane.Use the rock stratum of dilution can better separate the gaseous fluid that is injected.Acting on pressure on the rock stratum will improve and gaseous fluid mixture is separated into the part that is enriched on the more weak fluid-absorbent and be enriched in part on the strong fluid-absorbent.In a word, the pressure that acts on the rock stratum is higher, be adsorbed on the carbon containing parent rock in the rock stratum gaseous fluid just the more.

Generally will be enriched in more weak fluid-absorbent part (back is sometimes referred to as raffinate) by producing well extracts out from the rock stratum.Raffinate is enriched on the relatively more weak fluid-absorbent, and this is to pass the rock stratum because the more weak fluid-absorbent of being adsorbed by the carbon containing parent rock resembles lentamente foregoing.

Reclaiming raffinate strong fluid-absorbent in raffinate from the rock stratum is increased to more than the receivable degree.For the fluid-mixing that contains carbon dioxide, the carbon dioxide percent by volume in the raffinate preferably remains below 50%, more preferably is lower than 20%, most preferably is lower than 5%.In some cases, it is possible the carbon dioxide percent by volume in the raffinate being remained below 1%.

In addition, the continuous injection of gaseous fluid mixture is till reaching the required saturation ratio in rock stratum.Required absorption saturation ratio can be measured by routine test in the rock stratum.For example, mist can inject, and the percent by volume of strong fluid-absorbent is brought up to more than the above-mentioned receivable degree in raffinate.In case reach the saturation ratio of required absorption in the rock stratum,, can further recover the adsorption capacity of carbon containing parent rock by reducing the pressure on the rock stratum.When the gross pressure in the rock stratum reduces, being discharged in the carbon containing parent rock of the absorbate of desorb from the rock stratum on the stronger relatively fluid-absorbent will be enriched in.By injecting and producing well, can from the rock stratum, reclaim this by the absorbate of desorb.

If gaseous fluid mixture is separated in containing the rock stratum of carbon dioxide, for example, waste gas will be enriched in the carbon dioxide by the absorbate of desorb so.If mist comprises oxygen, for example, air will be enriched on the oxygen by the absorbate of desorb so.That reclaims can be re-injected in the solid carbon subterranean strata by the absorbate of desorb.For example, separate in the solid carbon subterranean strata if contain the gaseous fluid mixture of carbon dioxide, that reclaims so will be enriched in the carbon dioxide by the absorbate of desorb.The raising that will be used to by the absorbate of desorb that is enriched in the recovery in the carbon dioxide is reclaimed methane from the solid carbon subterranean strata.

Wish and to remain in the rock stratum than the high current body.In this case, the pressure that acts on the rock stratum can not descend, and the adsorption capacity of the carbon containing parent rock in the solid carbon subterranean strata is no longer recovered.In addition, do not drop in gross pressure and to make undesirable component, as carbon dioxide, hydrogen sulfide or carbon monoxide, if present, desorbed, and the stage that from parent rock, discharges, the adsorption capacity of the carbon containing parent rock in the rock stratum just has part no longer to recover.

In a word, employed pressure is such selection in the gaseous mixture separating process of fluid, so that determine the optimum condition of separation of the fluid.In general, the pressure of use is higher, by the gaseous fluid of the absorption of the carbon containing parent rock in the rock stratum just the more.For the system of being given, raffinate is got rid of faster from this system, and the percentage that contains strong relatively fluid-absorbent in the raffinate is just higher.

If comprise the nitrogen of higher proportion in the fluid-mixing that is separated, so last raffinate will be enriched on the nitrogen.For example, the mist that contains the nitrogen of larger proportion comprises air and waste gas.The raffinate of the enriched in nitrogen that use produces from these mists helps to reclaim methane from the solid carbon subterranean strata.Thinking that dehydration will reduce potential etching problem, can cause being used for waste gas is injected into the injection device in the rock stratum and the corrosion of well head.

During reservoir pressure in being higher than the rock stratum, the raffinate of enriched in nitrogen is injected in the solid carbon subterranean strata.Preferably, pressure is about 3,447, and 378-10, when being higher than the formation pressure in the rock stratum, injects the raffinate of enriched in nitrogen at 342,136 Pascals.If injection pressure is less than or equal to reservoir pressure, can not inject the raffinate of enriched in nitrogen so, this is because it can not overcome reservoir pressure.Enriched in nitrogen is preferably under the dividing potential drop that is lower than the solid carbon subterranean strata to be injected.If the pressure that injects is too high and thoroughly break in the rock stratum, the raffinate of enriched in nitrogen just might lose, and the methane of producing is few.

Yet, according to research, think when pressure is higher than the rock stratum partial pressure to other reservoir, as long as does not extend to producing well from injecting well in caused crack, just the raffinate of enriched in nitrogen can be injected in the rock stratum.In fact, be in the rock stratum dividing potential drop when above at pressure, in order to reach the sufficient injection and/or the rate of recovery, need inject, thereby make process economics, perhaps in other cases, also can need to inject in order to reach improvement investment result, not abandon whole operations when doing.Half of the fracture length that causes in the rock stratum is approximately less than the 20%-30% that injects the distance between well and the producing well.The crack of being caused preferably remains in the rock stratum in addition.

Reclaim the important parameter of methane,, can measure by known rock stratum analogue technique as fracture half-length, fracture orientation and highly growth.These technology are disclosed in that Petroleum Engineer association disquisition is collected, in the cracked coal seam of the waterpower latest tendency by people such as John L. work in 1989, the 12nd, 25-29 page or leaf and the 76-77 page or leaf; With introduced in Petroleum Engineer association technology annual meeting in 1978 and the exhibition held Houston, Texas 1-3 in October day, by Schuster, " surveying the seismic signal that well head is produced by the cracked coal seam of waterpower " paper SPE7448 that C.L. writes.In addition, combination by pressure transient state analysis instrument and natural gas reservoir flow model, can determine the direction of fracture half-length and impact, the exhibition of the Petroleum Engineer association that paper SPE " the above action direction that injects of the crack dividing potential drop in Norway Valhal mining area " that described model is disclosed in the 69th technology annual meeting of Petroleum Engineer association, write by people such as N.Ali and Dallas, in October, 1991 6-9 day Texas hold.Think that simultaneously above list of references described a kind of being used for by inject the method that water improves the recovery of oil more than the dividing potential drop of crack, think simultaneously to be applicable to from the solid carbon subterranean strata, to increase in method described in the SPE22893 and technology and to reclaim methane.

In a word, the solid carbon subterranean strata is darker, and it is just higher that the enriched in nitrogen raffinate is injected in the rock stratum needed pressure.Usually the pressure that injects is 2,757,903-13, and 789,514 Pascals just are enough to the enriched in nitrogen raffinate is injected into and wish to reclaim in the most rock stratum of methane.

Injection well by being communicated with formation fluid is injected into the solid carbon subterranean strata with the enriched in nitrogen raffinate.Inject well and preferably be penetrated into the rock stratum that contains methane, but as long as the rock stratum with inject that fluid is communicated with between the well, the injection well does not just need to be penetrated into the rock stratum that contains methane.The injection of enriched in nitrogen raffinate can adopt continuation mode or intermittent mode to carry out.The pressure that injects can remain on the pressure of pressure stable or variation.

From with producing well that formation fluid is communicated with back production contain the fluid of methane.As injecting well, producing well preferably is penetrated in the rock stratum that contains methane and goes, but as long as fluid is communicated with between rock stratum and producing well, producing well does not go with regard to not needing to be penetrated in the rock stratum.Use described producing well or well with the method the same with traditional coal bed methane recovery well.Reclaiming by that producing well in the process of the fluid that contains methane, wishing to make the back pressure in the producing well be in minimum.The reduction of back pressure will help to contain the fluid of methane from the rock movement to the well head in the producing well.

Producing well is preferred to be used like this, so that be lower than original pressure store in the rock stratum near the pressure near the producing well of the pithead position the methane production rock stratum.Be in the well head scope near near the pithead position the methane production rock stratum, and not in the rock stratum.Original pressure store is near the pressure store of that time before the enriched in nitrogen raffinate is injected in the rock stratum producing well.In the process of injecting the enriched in nitrogen raffinate, pressure store might improve, but thinks that the pressure near the rock stratum preferably remains below original pressure store in the producing well.Like this with enhance fluid from the rock movement to the well head.Pressure near well head place, methane production rock stratum in the producing well is preferably lower than about 2,757,903 Pascals.

In certain embodiments, the back pressure in the producing well well head is preferred, and is for example, when it would be desirable the pressure store that keeps higher, minimum so that the aquifer around making flow into the influx of the water in the rock stratum.The influx that flows into the water in the rock stratum can reduce the rate of recovery of methane, and make the construction of producing well become complicated.

When the another kind of situation that can better keep the well head back pressure of producing well is near the deposition and/or condensation of solid and/or liquid relevant wellhole or in the rock stratum in the wellhole.The deposition and/or the condensation of solid and/or liquid near the rock stratum that wellhole is or wellhole is interior will make methane recovery reduction in the producing well.Outside may depositing or be condensate near the wellhole and to have the material of a problem be the wax that contains occluded oil, described occluded oil can circulate in D-horizon and flow to producing well.Think high pressure in the wellhole of producing well will make near this wellhole or the deposition of solid in the wellhole or gas and/condensation drops to minimum.Therefore, if deposition and condensation in the wellhole become a problem, so the pressure in the wellhole of producing well is brought up to resemble actual uses high pressure better possible.

Time and increment that methane recovery in the producing well increases will depend on many factors, these factors comprise, as thickness, bedding hole, injection pressure and the injection rate of well spacing, solid carbon subterranean strata, the fluid components of injection, adsorbed gaseous fluid component, pressure store, the permeability of rock stratum and the methane total amount before the injection enriched in nitrogen raffinate.

When aforesaid parameter is remained unchanged, producing well and the distance of injecting between the well cause the reaction (raising of methane recovery and enriched in nitrogen raffinate are injected into the short time before the rock stratum) of observable producing well than the young pathbreaker, and the reaction that distance is bigger between well and the producing well is fast than injecting.When well is separated, requirement that methane recovery improves rapidly and other factor balance each other, these factors are as the early stage nitrogen critical point when the well spacing that use to shorten and methane is desorbed the amount of employed enriched in nitrogen raffinate from the rock stratum of giving determining deviation.

If desired, the methane that the present invention produced can be separated with produced simultaneously gaseous fluid, as the mixture of nitrogen or nitrogen and arbitrary gas or the gaseous fluid that is injected into or produce from the solid carbon subterranean strata.Certainly, this produced simultaneously gaseous fluid will comprise the gaseous fluid of any naturally-occurring in the solid carbon subterranean strata with methane.These are commonly referred to as coal bed methane with the abiogenous gaseous fluid of methane.These spontaneous gaseous fluids comprise, as hydrogen sulfide, carbon dioxide, ethane, propane, butane and a spot of heavy hydrocarbon.If desired, the methane that the present invention produced can with mix mutually from the methane that contains in the small amount of impurities.

Embodiment 1

Present embodiment represents that various desorb fluids are injected in the coal seam so that the coal seam curve of the prediction when helping to reclaim methane from the coal seam.In the present embodiment, injection is in year point beginning.Desorb fluids all among this embodiment, are injected in the coal seam under 514 Pascals' the injection pressure 13,789.The desorb fluid that is injected in the rock stratum comprises:

Purity nitrogen;

Contain percent by volume and be 85% nitrogen and percent by volume and be the waste gas of 15% carbon dioxide;

Mixture etc. mole of carbon dioxide and nitrogen;

Contain percent by volume and be 85% carbon dioxide and percent by volume and be the desorb fluid of 15% nitrogen; With

Pure carbon dioxide.

The data that Fig. 1-7 is represented are to produce by designed model.Designed model is thick and suppose the coal seam uniformly on vertical and horizontal direction in order to describe one 3.05 meters.The data of representing with curve are corrected as 15.6 ℃ of temperature, pressure 101,353 Pascals.The coal seam of supposing has following performance:

Permeability=10 millidarcies;

Degree of porosity=0.5%;

Before injecting the desorb fluid, reservoir pressure is 10,342,136 Pascals; And reservoir temperature=46.1 ℃.

Described coal seam is saturated by methane, and is 186,155 square kilometres rock stratum by producing well institute consumed area.In this model, suppose producing well by four injection wells round, these inject wells and are arranged in rock stratum, five places.Suppose that each injects 1/4th the reaction that acts on producing well and producing well with identical method owing to each injection well.The desorb fluid of the accumulation that is injected into the rock stratum and is discharged by producing well is from four injection wells.Each injects well and contributes 1/4th total desorb fluids that injected.Fig. 1-7 has represented that the gaseous fluid rate of recovery (standard cubic meters every days 1,000 (MSCM/Day)) of prediction and the gaseous fluid of expression accumulation reclaim (1,000,000 standard cubic meters (MMSCM)).

Employed model is to design by two-dimentional Virial equation of state.To the explanation of Virial equation of state with how to use them to make and model like the employed model class of the inventor, this model is disclosed in DeGance, " the multicomponent high pressure adsorption equilibrium on the carbonizable substance: theory and data " fluid balance, 78 years 99-137, (1992) the Elsevier science and technology B.V. of publishing house, Amsterdam; Here introduce with as a reference.

Can see that from Fig. 1 and 5 time of one section continuity after the desorb fluid begins to inject, the carbon dioxide in the fluid that is reclaimed in the producing well remains below the percent by volume of the desorb fluid institute carbonated of injection.The time that carbon dioxide percent by volume in the fluid that is reclaimed begins to increase is approximately identical with the methane percent by volume time that begins to descend in the fluid that is reclaimed.Can see that from Fig. 2 and 5 the carbon dioxide percent by volume of the actual percentage of contained methane in the fluid that is reclaimed is increased to the carbon dioxide percent by volume of the desorb fluid that is injected and reclaimed above the time in the rock stratum.In addition, because methane can be used for carbon dioxide is separated economically with methane, nitrogen and other fluid, can be with two vaporized carbons and the fluid separation that from producing well, reclaims, and it oppositely is injected into coal seam and/or near other coal seam.

Fig. 1-7 has also shown the ratio of the desorb fluid components of other injection in carbon dioxide and the fluid that reclaims from producing well, reach before the ratio of desorb fluid components of other injection contained in carbon dioxide and the desorb fluid that injected the actual percentage of the methane that can be recovered to from the zone that producing well is discharged.

Should be noted that because model in above-mentioned example and below embodiment be Utopian, do not consider the inhomogeneities that exists in the actual solid carbon subterranean strata.Therefore, the model of describing in this model and embodiment 2 and 3 can not be predicted contingent streak in the rock stratum.Yet the disclosed embodiment of the minimizing of the streak in aforesaid rock stratum can make those of ordinary skill realize the present invention.

Embodiment 2

Present embodiment represents that the desorb fluid that contains carbon dioxide is injected in the coal seam so that improve the coal seam curve of the prediction when reclaiming methane from the coal seam.In the present embodiment, the injection of desorb fluid begins after 4 years exhaust.Desorb fluids all in the present embodiment are 13,789, under 514 Pascals' the injection pressure, pass have the top layer-3 injection well, are injected in the coal seam.The downhole production pressure of this producing well is 689,476 Pascals, and top layer-3.The top layer is near the infiltrative scope the wellhole rock stratum.Near the loss the wellhole is represented on positive top layer, and near the facilitation the wellhole is represented on negative top layer.The desorb fluid that is injected in the rock stratum comprises:

Pure carbon dioxide; With

Contain percent by volume and be 70% carbon dioxide and percent by volume and be the desorb fluid of 30% methane.

The data that Figure 11-18 is represented are to produce by designed model.Designed model is thick and suppose the coal seam uniformly on vertical and horizontal direction in order to describe one 15.24 meters.The data of representing with curve are corrected as 15.6 ℃ of temperature, pressure 101,353 Pascals.The coal seam of supposing has following performance:

Permeability=5 millidarcies;

Before injecting the desorb fluid, reservoir pressure is 10,342,136 Pascals; With

Reservoir temperature=46.1 ℃.

Described coal seam is saturated by methane, and is 647,497 square kilometres rock stratum by producing well institute consumed area.In this model, suppose producing well by four injection wells round, these inject wells and are arranged in rock stratum, five places.Supposing that each injects with identical method influences 1/4th reaction of producing well and producing well owing to each injection.The desorb fluid of the accumulation that is injected into the rock stratum and is discharged by producing well is from four injection wells.Each injects well and contributes 1/4th total desorb fluids that injected.

Employed model is to design by the Langmuir absorption isotherm model that extends.To the explanation of the Langmuir absorption isotherm model that extends with how to use it to make and model like the employed model class of the inventor, this model is disclosed in the SPE24363 that Petroleum Engineer association 1992 announces, " the adsorbing modeled coal bed methane production of binary gas " paper of writing on the 459-472 page or leaf, by people such as L.E.Arri; Here introduce with as a reference.Present embodiment shows under the situation known to some those of ordinary skill, the desorb fluid that comprises carbon dioxide and methane helps to reclaim methane from the solid carbon subterranean strata, particularly under the too high situation of the cost that methane is separated from the waste gas stream that is reclaimed.In this case, the rock stratum that fluid is re-injected into the absorbing carbon dioxide component stream and allow methane to pass to reclaim the producing well of usefulness.

Embodiment 3

That uses among the employed analogue technique of present embodiment and parameter and the embodiment 2 is identical.But in the present embodiment, used unsaturated coal seam, and the mist that will have the nitrogen of the carbon dioxide of 15% percent by volume and 85% percent by volume is injected in the coal seam.Begin the zero point that is infused in of gaseous fluid.Example shown in Fig. 8-10 shows that when the gaseous fluid that contains carbon dioxide and nitrogen is injected in the rock stratum solid carbon subterranean strata can provide the fluid that is rich in nitrogen effectively.This model estimates that the nitrogenous percent by volume in the fluid that is reclaimed will be 100% in all processes shown in Fig. 8-10; In all processes shown in Fig. 8-10, the carbonated percent by volume in the fluid that is reclaimed will be increased to more than 0.01%.

Think to be injected into the rock stratum by injecting well, and when discharging by producing well, the solid carbon subterranean strata also will provide a kind of fluid that is rich in nitrogen at air.

According to the above, will see that many variations, improvement and modification are conspicuous for those of ordinary skill.Therefore, this description only is to carry out according to diagram, and is used to instruct those of ordinary skill to implement method of the present invention.For can change described in the application, material can be replaced.For example, think that the gaseous fluid of the carbonaceous material of chemisorbed in the rock stratum can utilize the similar processing method of handling in the rock stratum of fluid-absorbent by force handling in the rock stratum.

Like this, in not breaking away from the scope of the present invention that limits by claims, can make various modifications, replacement and change etc.Certainly all such modifications all fall into the claims that added.

Claims

1. one kind from by injecting the method that solid carbon subterranean strata that well and producing well pass reclaims methane, and this method comprises the following steps:

A) volume ratio that will have a desorb fluid components of carbon dioxide and other injection equals the desorb fluid of B, is injected into the rock stratum by injecting well;

B) will comprise that by producing well the volume ratio of the desorb fluid components of methane and carbon dioxide and carbon dioxide and other injection is lower than the waste gas extraction of B from the rock stratum; With

C) in step b), the volume ratio of the carbon dioxide in the gaseous fluid of being extracted out and the desorb fluid components of other injection just stops the attitude fluid of bleeding during greater than 0.5B from the rock stratum.

2. method according to claim 1 is characterized in that the solid carbon subterranean strata comprises at least one coal seam.

3. method according to claim 1 is characterized in that the desorb fluid that is injected comprises waste gas.

4. method according to claim 1 is characterized in that the desorb fluid that is injected comprises the carbon dioxide that 49% percent by volume is above.

5. method according to claim 4 is characterized in that the desorb fluid that is injected comprises methane and carbon dioxide.

6. one kind is used for method that the gaseous fluid mixture in coal seam is separated, and this method comprises the following steps:

A) will contain more weak fluid-absorbent component and be injected in the coal seam than the gaseous fluid mixture of high current body component;

B) from the coal seam, reclaim the raffinate that is enriched on the more weak fluid-absorbent component;

C) on the coal seam, form gross pressure;

D) gross pressure on the reduction coal seam is so that make the adsorbate that is enriched on the strong fluid-absorbent component desorb from the coal seam; With

E) taken out from the coal seam by the adsorbate of desorb to major general's part.

7. method according to claim 6 further comprises:

A) by injecting well, raffinate is injected in second coal seam; With

B) from second coal seam, reclaim methane.

8. method according to claim 6 is characterized in that the gaseous fluid mixture that is input in the step a) coal seam comprises waste gas, and the raffinate that reclaims from the coal seam is rich in nitrogen.

9. method according to claim 6 comprises methane in the raffinate that it is characterized in that reclaiming in the step b).

10. method according to claim 6, the gaseous fluid mixture that it is characterized in that being input in the step a) coal seam comprises methane and carbon dioxide.