CN106932323B - A kind of shale gas reservoir gas effecive porosity inversion method - Google Patents
A kind of shale gas reservoir gas effecive porosity inversion method Download PDFInfo
- Publication number
- CN106932323B CN106932323B CN201710095343.4A CN201710095343A CN106932323B CN 106932323 B CN106932323 B CN 106932323B CN 201710095343 A CN201710095343 A CN 201710095343A CN 106932323 B CN106932323 B CN 106932323B
- Authority
- CN
- China
- Prior art keywords
- porosity
- gas
- shale
- formula
- effecive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/088—Investigating volume, surface area, size or distribution of pores; Porosimetry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/088—Investigating volume, surface area, size or distribution of pores; Porosimetry
- G01N15/0893—Investigating volume, surface area, size or distribution of pores; Porosimetry by measuring weight or volume of sorbed fluid, e.g. B.E.T. method
Abstract
The present invention provides a kind of shale gas reservoir gas effecive porosity inversion methods comprising following steps: (1), according to mass conservation law, the shale effecive porosity inversion formula of foundation consideration adsorbed gas and free gas；(2), shale gas reservoir absolute porosity is measured using helium, obtains helium measurement absolute porosity, inverting obtains practical shale respectively to the effecive porosity of methane and carbon dioxide on the basis of the helium measures absolute porosity；Or using nitrogen measurement shale gas reservoir to the effecive porosity of nitrogen, obtain the effecive porosity of nitrogen measurement, inverting obtains shale absolute porosity on the basis of the nitrogen measures effecive porosity, then obtains practical shale respectively to the effecive porosity of methane and carbon dioxide by the absolute porosity inverting.
Description
Technical field
The present invention relates to a kind of shale gas reservoir gas effecive porosity inversion methods, and in particular to a kind of shale gas reservoir is practical
Effecive porosity inversion method under the influence of formation fluid suction-operated belongs to the untraditional reservoir development technique of petroleum industry
Field.
Background technique
Shale gas is mainly with free, Unconventional gas of the adsorbed state preservation in dark-coloured mud shale, the hole of shale
Gap is characterized in determining the key factor of shale reservoir gas-bearing property.Shale porosity is evaluation shale reservoir physical property, calculates gas storage
The important parameter of amount, how to carry out effectively analysis to shale porosity is that the technology that progress shale gas exploration and development must solve is asked
Topic.
Currently, shale porosity determination method is mainly mercury injection method, nuclear magnetic resonance method, scanning electron microscopy, gas survey
Method etc..Since shale hole is mainly nanoscale hole, pore size is smaller, when being measured using mercury injection method, liquid mercury be difficult into
Enter, high-pressure mercury is easy to damage by pressure on rock sample again, forms crack, influences porosity determination result.Nuclear magnetic resonance method and scanning electron are aobvious
Micro mirror method experiment equipment is expensive, is not suitable for the lacunarity analysis of a large amount of rock samples.Gas survey method, which can measure mercury injection method, cannot be introduced into
Hole, measuring accuracy is higher, and test equipment is again expensive not as good as nuclear magnetic resonance and scanning electron microscope, therefore scholars mostly use
Gas surveys method and measures shale rock sample porosity.Shale porosity gas during surveying it is general using it is more stable, safely, the nitrogen that is easy to get
(N2) or helium (He), and in shale gas failure recovery process and CO2In displacement process, the fluid actually flowed is CH4With
CO2, due to N2With He and CH4、CO2In the characterization of adsorption of shale surface, high pressure property there are larger difference, lead to that survey will be tested
The porosity value obtained, which directly applies to, measures CH4、CO2Effecive porosity during generate biggish error.Based on the above original
Cause, currently used porosity air testing method cannot accurately reflect CH in practical shale gas reservoir4、CO2Active porosity angle value,
Therefore it needs indoor N2Or the experimental data that He is measured carries out inverting, to obtain CH under the conditions of practical gas reservoir4、CO2Have
Porosity value is imitated, then present applicant proposes a kind of shale gas reservoir effecive porosity inversion methods.
Summary of the invention
In order to solve the above shortcomings and deficiencies, the purpose of the present invention is to provide a kind of shale gas reservoir gas active porosities
Spend inversion method.
In order to achieve the above objectives, the present invention provides a kind of shale gas reservoir gas effecive porosity inversion methods comprising
Following steps:
(1), according to mass conservation law, the shale effecive porosity inversion formula for considering adsorbed gas and free gas is established；
(2), shale gas reservoir absolute porosity is measured using helium, obtains helium measurement absolute porosity, is surveyed in the helium
Inverting obtains practical shale respectively to the effecive porosity of methane and carbon dioxide on the basis of determining absolute porosity；
Or the effecive porosity of nitrogen measurement is obtained to the effecive porosity of nitrogen using nitrogen measurement shale gas reservoir,
Inverting obtains shale absolute porosity on the basis of the nitrogen measures effecive porosity, then is obtained by the absolute porosity inverting
Practical shale is respectively to the effecive porosity of methane and carbon dioxide.
In the described method, it is preferable that such as following formula (15) institute of shale effecive porosity inversion formula described in step (1)
Show；
φe=φab(1+f) (15)；
In formula (15), φ e is effecive porosity of the gas in shale, and φ ab is that the shale that helium gas survey method measures is absolute
Porosity or nitrogen gas survey the shale absolute porosity that method inverting obtains, and f is that methane or carbon dioxide effecive porosity are corrected
Coefficient, wherein f is calculated by following formula (14):
In formula (14), ρadsTo adsorb air tightness, ρgFor eudiometry density, φ ads is shale adsorbed gas porosity.
In the described method, it is preferable that when using helium measurement, the helium that is obtained by the inverting in step (2)
Absolute porosity is measured to practical shale respectively to inversion formula such as following formula (28) institute of methane and carbon dioxide effecive porosity
Show；
In formula (28), φ ab, He are the absolute porosity of helium measurement, ρrFor rock density, VLAdsorbent is saturated for single layer
Product,For mole, p is shale gas reservoir pressure, BgFor gas volume factor, Z is Gas Compression Factor, and R is Avobenzene gal
Moral sieve constant, T are temperature,
ξ is the ratio between adsorbed gas and free air tightness, and usual value is 1.8-2.5, and C is to adsorb related constant with net heat,
p0It is saturated adsorptive pressure for gas, N is the absorption number of plies.
In the described method, it is preferable that when using helium measurement, the effecive porosity inverting of actual formation gas i is public
Formula are as follows:
φi,e=φab,He(1+fi,He) (16)；
In formula (16), actual formation effecive porosity correction factor are as follows:
In formula (17), gas density expresses formula are as follows:
ρads=ξ ρg(22)；
In formula (22), ξ=aebp；Wherein, a, b are adsorbed gas bulkfactor, and related with gas type, rock forming mineral, p is
Pressure；
When considering multilayer absorption, adsorption layer gas volume calculates formula:
In formula (23),
Thus adsorption layer gaseous porosity is obtained:
By intermediate variable GaIt is brought into adsorption layer gaseous porosity formula:
The effecive porosity correction factor expression formula of actual formation gas i when thus obtaining measuring porosity using helium:
By formula (27) substitute into formula (16), obtain helium measure porosity to actual formation gas i effecive porosity it is anti-
Drill formula:
In the described method, it is preferable that when using nitrogen measurement, shale absolute porosity described in step (2) is under
Formula (37) is calculated,
In formula (37), φa,N2For the effecive porosity using shale gas reservoir when nitrogen measurement to nitrogen.
In the described method, it is preferable that when using nitrogen measurement, pass through the absolute porosity inverting in step (2)
It obtains shown in inversion formula such as following formula (39) of the practical shale respectively to the effecive porosity of methane and carbon dioxide；
In formula (39), φ ab, N2Shale gas reservoir absolute porosity when being measured for nitrogen.
In the described method, it is preferable that when using helium measurement, this method further includes measuring respectively at various pressures
Unit mass shale CH4And CO2The operation of adsorbance.The present invention measures unit mass shale CH under different pressures4And CO2Absorption
After amount, then passes through the adsorbance experimental data regression fit (conventional technical means in the art) and obtain VL、C、p0、N。
In the described method, it is preferable that when using helium measurement, the pressure is 0-5 × 106MPa.Wherein, this hair
Unit mass shale CH under bright measurement different pressures4And CO2Method used in adsorbance is conventional technical means in the art, and
The present invention does not also make specific requirement to the interval of pressure, and those skilled in the art can need rationally setting should according to field operation
Pressure intervals, as long as guaranteeing that the object of the invention may be implemented.
In the described method, it is preferable that when using nitrogen measurement, this method further includes measuring respectively at various pressures
Unit mass shale N2、CH4And CO2The operation of adsorbance.The present invention measures unit mass shale N under different pressures2、CH4And CO2
After adsorbance, then V obtained by the adsorbance experimental data regression fitL、C、p0、N。
In the described method, it is preferable that when using nitrogen measurement, the pressure is 0-5 × 106MPa.Wherein, this hair
Unit mass shale N under bright measurement different pressures2、CH4And CO2Method used in adsorbance is conventional technical means in the art, and
And the present invention does not also make specific requirement to the interval of pressure, those skilled in the art can need rationally setting according to field operation
The pressure intervals, as long as guaranteeing that the object of the invention may be implemented.
Shale gas reservoir gas effecive porosity inversion method technical solution provided by the present invention described in detail below:
(1), according to mass conservation law, the shale effecive porosity inversion formula for considering adsorbed gas and free gas is established；
As shown in Fig. 1 shale matrix pores schematic diagram, shale total pore volume (Vab) it include free gas volume (Vf) and inhale
Attached air volume (Vads)。
In shale reservoir, the volume of adsorbed gas usually accounts for the 20-80% of total pore size volume, and it is long-range to adsorb air tightness
In the density of free gas, so this partial volume and its influence to effecive porosity cannot be ignored.According to mass conservation law,
In shale hole, the gross mass of gas will be equal to adsorbed gas and free gas quality sum, as shown in following formula (1).
Mt=ρadsVads+ρfVf(1)；
Then in shale hole gas effective volume are as follows:
As shown in Figure 1, total pore size volume is the sum of free gas volume and adsorbed gas volume.
Vab=Vads+Vf(4)；
Vf=Vab-Vads(5)；
With total pore size volume and adsorbed gas volume characterization shale active porosity volume:
Then shale effecive porosity expression formula:
By formula (7), adsorbed gas porosity and absolute porosity are defined:
Formula (8), formula (9) are updated to formula (7), then shale effecive porosity can turn to:
Due to underground gas density and shale hole free gas equal density, it may be assumed that
ρg=ρf(11)；
Therefore shale effecive porosity are as follows:
Further abbreviation obtains the shale effecive porosity inversion formula for considering adsorbed gas and free gas
Enable effecive porosity correction factor are as follows:
Then shale effecive porosity inversion formula are as follows:
φe=φab(1+f) (15)。
It, can be by the absolute porosity φ that measures or be calculated by formula (15)abIt is calculated and considers adsorbed gas volume
And the effecive porosity of free gas volume.
(2) helium absorption property is very weak, usually ignores, then helium measurement result is shale absolute porosity, establishes
Consider that the helium in the case of adsorption layer measures absolute porosity to practical shale respectively to CH4And CO2The inverting of effecive porosity is public
Formula.
Helium gas gaging hole porosity is to be measured rock sample interconnected pore using helium as gas medium, obtained effecive porosity
A kind of method (Mullen J.Petrophysical Characterization of the Eagle Ford Shale in
South Texas[J].Society of Petroleum Engineers,2010.).Pore volume measurement is swollen by helium
Helium is realized (Sondhi from sample room of the precompression chamber of the known volume indentation with rock sample by swollen principle
N.Petrophysical characterization of eagle ford shale[D].Oklahoma:University
of Oklahoma,2011.).Since helium gas molecules radius is smaller, small helium gas molecules adsorptivity in shale hole is poor, because
By the shale porosity of helium measurement, there is no the volumes for considering adsorption layer gas for this, cause measurement result inaccurate.By above
It derives, obtains the actual formation porosity calculation formula for considering adsorbed gas and free gas, i.e. formula (15).
Since helium is without adsorptivity, so the porosity measured is absolute hole when measuring porosity by helium
Spend φab, i.e., the porosity is built upon free gas is all in pore volume under conditions of measure, however the stream in actual formation
Body has adsorptivity, and adsorption layer gas physical property is different with free gas physical property, thus we it is necessary to measure to it
Porosity be modified, obtain the effecive porosity of real gas.
When will derive helium measurement below, shale gas reservoir actual formation effecive porosity inversion formula.
If measured with helium (He), actual formation gas i (CH4And CO2) effecive porosity inversion formula are as follows:
φi,e=φab,He(1+fi,He) (16)；
By above formula, under conditions of considering actual formation adsorbent volume, actual formation effecive porosity correction factor
Expression formula are as follows:
According to Boyle's law, The Ideal-Gas Equation are as follows:
PV=ZnRT (18)；
By above formula, the expression formula of unit molal volume:
By the relational expression of quality and density:
This makes it possible to obtain gas densities to express formula:
Absorption air tightness and free air tightness meet following relationship (Azom, P.N.and Javadpour, F., Dual-
continuum modeling of shale and tight gas reservoirs.SPE 159584presented at
the SPE Annual Technical Conference and Exhibition,8-10October,San Antonio,
Texas, USA, 2012.):
ρads=ξ ρg(22)；
In formula (22), ξ=aebp；Wherein, a, b are adsorbed gas bulkfactor, and related with gas type, rock forming mineral, p is
Pressure.
By BET isothermal adsorption law (Brunauer S, Emmett P H, Teller E.Adsorption of Gases
In Multimolecular Layers [J] .J.am.chem.soc, 1938,60 (2): 309-319. and Wang, J., Luo,
H.,Liu,H.,Ji,Y.,Cao,F.,Li,Z.,Sepehrnoori,K.Variations of gas flow regimes and
petro-physical properties during gas production considering volume consumed
by adsorbed gas and stress dependence effect in shale gas reservoirs.Paper
SPE174996presented at the SPE Annual Technical Conference and Exhibition,
2015b, 28-30.) can must consider multilayer absorption when, adsorption layer gas volume calculate formula:
In formula
It can thus be concluded that adsorption layer gaseous porosity:
By intermediate variable GaIt is brought into adsorption layer gaseous porosity formula:
It is hereby achieved that actual formation gas i (CH when measuring porosity using helium4And CO2) effecive porosity repair
Positive coefficient expression formula:
Formula (27) are substituted into formula (16), helium can be obtained and measure porosity to actual formation gas i (CH4And CO2) effective hole
The inversion formula of porosity:
If using nitrogen measure shale porosity, due to nitrogen equally with actual formation gas absorption characteristic and high pressure object
Property difference, will establish below and shale porosity is measured to actual formation gas i (CH by nitrogen4And CO2) effecive porosity
Inversion formula.
Nitrogen gas surveys shale porosity principle: with nitrogen as Adsorbate Gas, under conditions of keeping temperature-resistant, by
Edge up the partial pressure of high gas, and constantly adsorbance of the test sheets rock rock sample under different partial pressures, thus makes adsorbance and partial pressure
Relation curve, as adsorption isotherm；Similarly, it after boosting, is gradually depressured, measures under different partial pressures again in turn
Thus desorption rate makes the relation curve of desorption rate and partial pressure, as desorption isotherm；The pore volume of shale is by gas absorption
The adsorbance of matter at boiling temperature calculates (Xie, X., Tang, H., Wang, C., Bai, R., &Wang, Z..Contrast of
nitrogen adsorption method and mercury porosimetry method in analysis of
shale's pore size distribution.Natural Gas Industry,2006,26(12),100-102.)。
Shale porosity working principle is measured by nitrogen it is found that it includes adsorbed gas that nitrogen gas, which surveys obtained pore volume,
Volume and free gas volume compare helium measurement result, precision increases, but nitrogen molecule exists from the point of view of measurement result
Characterization of adsorption and high pressure property and actual formation gas (CH in shale hole4And CO2) there are still larger differences, therefore use nitrogen
The porosity of gas measurement directly characterizes shale to actual formation gas (CH4And CO2) effecive porosity be inaccurate.
Below by for the difference of nitrogen and actual formation gas absorption characteristic and high pressure property, establishes and hole is measured by nitrogen
Porosity is to actual formation gas i (CH4And CO2) effecive porosity inversion formula.
For He, there is absorption, therefore the effecive porosity measured by nitrogen in nitrogen in shale formationContain free gas and adsorbed gas two parts.In conjunction with effecive porosity derivation formula, it can derive that nitrogen measurement is page
The calculation formula of rock absolute porosity.
Convolution (3), when can obtain nitrogen measurement, shale is as follows to the active porosity volume expression formula of nitrogen:
Total pore size volume VabEqual to the sum of free gas volume and adsorbed gas volume.
Vab=Vads+Vf(30)；
Formula (30) is updated in formula (29), can be obtained:
When being measured this makes it possible to obtain nitrogen, the expression formula of shale effecive porosity:
Due to underground gas density and shale hole free gas equal density, it may be assumed that
ρg=ρf(34)；
When therefore obtaining nitrogen measurement, shale effecive porosity are as follows:
By formula (35), when can obtain nitrogen measurement, shale absolute porosity expression formula:
Formula (26) are substituted into formula (36), shale gas reservoir absolute porosity when can obtain nitrogen measurement:
By formula (15), practical shale gas of gas reservoir body i (CH4And CO2) effecive porosity inversion formula are as follows:
Formula (37) and porosity correction factor are substituted into formula (38), nitrogen can be obtained and measure porosity to the effective hole of actual formation
The inversion formula of porosity:
Wherein, φadsIt can be acquired by formula (26)；
(4) shale gas reservoir actual formation gas i (CH is calculated using inversion formula obtained above4And CO2) active porosity
Degree:
Based on the porosity that target shale gas reservoir helium or nitrogen measure, actual formation is calculated by above-mentioned inversion formula
Gas (CH4And CO2) effecive porosity, specifically includes the following steps:
1) shale absolute porosity or nitrogen measurement shale, are measured to nitrogen effecive porosity using helium；
2) density of shale rock, is measured；
If 3), the helium method of inversion to be used, CH is measured using pressure application4、CO2Adsorpting data (unit under different pressures
Quality shale adsorbs CH4、CO2Amount)；If measuring N using pressure application with the nitrogen method of inversion is used2、CH4、CO2Adsorption number
According to (unit mass shale adsorbs N under different pressures2、CH4、CO2Amount)；
4) actual formation gas CH, is calculated using the inversion formula that step (2) respectively obtains4、CO2It is effective
Porosity.
Professional term symbol used herein is shown in Table 1.
Table 1
The present invention existing shale gas reservoir effecive porosity air testing method there are aiming at the problem that:
(1) when He gas measurement porosity, since He gas and rock surface are without adsorptivity, measurement result does not consider that shale is inhaled
The volume of attached layer gas causes to test effecive porosity inaccuracy；
(2)N2When measuring porosity, N is not considered2With actual formation gas shale surface characterization of adsorption difference；
(3) He and N2The porosity of measurement does not consider the existing difference between real gas high pressure property.Therefore, this hair
It is bright to provide a kind of shale gas reservoir effecive porosity inversion method, firstly, according to mass conservation law, establish consider adsorbed gas with
The effecive porosity inversion formula of free gas；Then, do not consider the characteristic of adsorption layer gas for He measurement result, establish and consider
He in the case of adsorption layer measure absolute porosity to actual formation effecive porosity (because helium is without absorption, hole that helium measures
Porosity is exactly the effecive porosity of shale absolute porosity and shale to nitrogen) inversion formula；
Meanwhile for N2With the difference of actual formation gas absorption characteristic and high pressure property, establish by N2Measure active porosity
Spending actual formation gas effecive porosity, (porosity that nitrogen measures is effecive porosity of the shale to nitrogen, and the value is different
In shale absolute porosity, and it is greater than shale absolute porosity, different gas shale effecive porosities is different)
Inversion formula；Finally, the inversion formula obtained using the present invention is for He or N2The effecive porosity result of laboratory experiment measurement
Inverting CH4Absorption and CO2The effecive porosity of absorption.It solves existing shale gas reservoir effecive porosity gas by the above method to survey
Method there are the problem of, establish a kind of shale effecive porosity inversion method, improve shale gas reserves computational accuracy and shale gas
Failure exploitation, CO2Drive the reliability of simulation precision and conceptual design.
Technical solution of the present invention has the advantage that
1, adsorption layer gas volume is not considered the problems of when helium measures shale gas reservoir effecive porosity, it is contemplated that inhale
Attached layer specific gravity shared in shale hole, the i.e. volume of adsorption layer are no longer ignored, are obtained using the method for theory deduction
Consider the shale effecive porosity inversion formula that adsorption layer influences, solves and adsorbed when measuring porosity using helium because ignoring
The volume of layer and the problem of cause free gas volume to be overestimated, improve practical shale gas reservoir effecive porosity computational accuracy；
2, when for nitrogen measurement shale porosity, nitrogen adsorption characteristic, high pressure property and actual formation gas are not considered
(CH4And CO2) different problems, it is contemplated that the influence of nitrogen adsorption difference and high pressure property difference, using the method for theory deduction
The practical shale formation effecive porosity inversion formula for considering adsorbed gas volume and free gas volume is obtained, is solved due to nitrogen
Gas and actual formation gas (CH4And CO2) physical property difference caused by the inaccurate problem of effecive porosity test result.
Detailed description of the invention
Fig. 1 is shale matrix pores schematic diagram；
Fig. 2 is to calculate actual formation gas effecive porosity flow chart using inversion formula in the embodiment of the present invention；
Fig. 3 is the data and laboratory data measured that the inversion method provided through the invention in embodiment 1 is calculated
Comparison diagram；
Fig. 4 is the data and laboratory data measured that the inversion method provided through the invention in embodiment 2 is calculated
Comparison diagram.
Specific embodiment
In order to which technical characteristic of the invention, purpose and beneficial effect are more clearly understood, now in conjunction in detail below
Embodiment and Figure of description carry out following detailed description to technical solution of the present invention, but should not be understood as can to of the invention
The restriction of practical range.
Embodiment 1
Present embodiments provide a kind of shale gas reservoir gas effecive porosity inversion method, flow chart as shown in Fig. 2, from
In Fig. 2 as can be seen that the inversion method the following steps are included:
For the problem of helium (He) measurement porosity inaccuracy, this example calculates helium gas using inversion formula of the present invention
Porosity under the measurement of survey method, CH4Effecive porosity and CO under monolayer adsorption2Effecive porosity under multilayer absorption, and will
Calculated result of the present invention is compared with laboratory experiment result.
Wherein, calculating process the following steps are included:
1) method, is surveyed using helium gas and measures shale absolute porosity φAb, He, wherein helium gas surveys the concrete operations step of method
It suddenly is well known in the art；
φ is measured in the present embodimentAb, He=0.055；
2), using the density p of sedimentation balance method measurement shale rockr, wherein sedimentation balance method measurement material density concrete operations be
It is well known in the art；
ρ is measured in the present embodimentr=2450kg/m3；
3) CH, is measured using pressure application4、CO2Adsorpting data (under different pressures, unit mass shale adsorb CH4、CO2
Amount) and obtain V using experimental data regression fitL、C、p0,N；Wherein, CH4Adsorpting data it is as shown in table 2, CO2Absorption
Data are as shown in table 3, the V being fittedL、C、p0, N data it is as shown in table 4.
Table 2
| P, MPa | Adsorbance, m3/kg |
| 0 | 0 |
| 480334.7 | 3.731343 |
| 1335565 | 13.0597 |
| 2776569 | 20.70896 |
| 4897071 | 24.81343 |
Table 3
| P, MPa | Adsorbance, m3/kg |
| 0 | 0 |
| 337931 | 12.9771 |
| 1231034 | 36.64122 |
| 2462069 | 78.38931 |
| 3789655 | 130.5344 |
| 4405172 | 162.5954 |
Table 4
| Parameter | CH4 | CO2 |
| VL,kg/m3 | 0.00126 | 0.0016 |
| C | 1 | 4 |
| p0, MPa | 3.5 | 5.65 |
| N | 1 | 8 |
4) actual formation gas CH, is calculated using the inversion formula that the present invention obtains4And CO2Effecive porosity.It should
Formula is as follows:
In formula, φ ab, He are that helium measures absolute porosity, ρrFor rock density, VLIt is saturated adsorption volume for single layer,
For mole, p is shale gas reservoir pressure, BgFor gas volume factor, Z is Gas Compression Factor, and R is that Avogadro is normal
Number, T are temperature, and ξ is the ratio between adsorbed gas and free air tightness, and C is to adsorb related constant, p with net heat0It is saturated and adsorbs for gas
Pressure, N are the absorption number of plies.
Table 5 is other parameters used in the present embodiment calculating process, and table 6 is that the present invention calculates data and laboratory is surveyed
Fixed number is plotted in Fig. 3 according to contrast table, and by comparing result, wherein the experimental determination data in table 6 are originated from Aljamaan
H.M.,Experimental investigation of shale physical and transport properties.A
Report Submitted to the Department of Energy Resources Engineering of
Stanford University, 2013, and the experimental data is using pulse attenuation method (Brace W.F., Walsh
J.B.Frangos W.T.,Permeability of granite under high pressure,Journal of
Geophysical Research, 1968,173:2225-2236) obtain.
Calculated result of the present invention is almost the same with laboratory measurements as can be seen from the comparison result, illustrates with this hair
It is bright inverting to be carried out to shale gas reservoir gas gaging hole porosity, and computational accuracy is higher.
Table 5
Table 6
| Porosity | Directly surveyed with He | Experimental data | The present invention calculates data |
| CH4Monolayer adsorption effecive porosity | 0.055 | 0.108 | 0.1084 |
| CO2Multilayer adsorbs effecive porosity | 0.055 | 0.28 | 0.2801 |
Embodiment 2
Present embodiments provide a kind of shale gas reservoir gas effecive porosity inversion method, flow chart as shown in Fig. 2, from
In Fig. 2 as can be seen that the inversion method the following steps are included:
By laboratory experiment, nitrogen gas surveys method and measures shale porosity, CH4Effecive porosity and CO under monolayer adsorption2It is more
Effecive porosity under layer absorption, the porosity in the case of calculating three kinds with inversion formula of the present invention, by experimental result and meter
Result is calculated to compare.
Wherein, calculating process the following steps are included:
1) method, is surveyed using nitrogen gas and measures shale effecive porosity φA, N2, wherein nitrogen gas surveys the concrete operations step of method
It suddenly is well known in the art；
φ is measured in the present embodimentA, N2=0.06；
2), using the density data ρ of sedimentation balance method measurement shaler, wherein sedimentation balance method measurement material density concrete operations be
It is well known in the art；
ρ is measured in the present embodimentr=2450kg/m3；
3) N, is measured using pressure application2、CH4、CO2Adsorpting data (under different pressures unit mass shale adsorb N2、CH4、
CO2Amount) and obtain V using experimental data regression fitL、C、p0,N；Wherein, N2Adsorpting data it is as shown in table 7, CH4Suction
Attached data are as shown in table 8, CO2Adsorpting data it is as shown in table 9, the V being fittedL、C、p0, N data it is as shown in table 10.
Table 7
| P, MPa | Adsorbance, m3/kg |
| 0 | 0 |
| 530260.5 | 0.198582 |
| 1060521 | 0.775957 |
| 1777355 | 3.248227 |
| 2484369 | 3.319149 |
| 3191383 | 3.402624 |
Table 8
| P, MPa | Adsorbance, m3/kg |
| 0 | 0 |
| 480334.7 | 3.731343 |
| 1335565 | 13.0597 |
| 2776569 | 20.70896 |
| 4897071 | 24.81343 |
Table 9
| P, MPa | Adsorbance, m3/kg |
| 0 | 0 |
| 337931 | 12.9771 |
| 1231034 | 36.64122 |
| 2462069 | 78.38931 |
| 3789655 | 130.5344 |
| 4405172 | 162.5954 |
Table 10
| Parameter | N2 | CH4 | CO2 |
| VL,kg/m3 | 0.0001 | 0.00126 | 0.0016 |
| C | 1 | 1 | 4 |
| p0, MPa | 2.45 | 3.5 | 5.65 |
| N | 1 | 1 | 8 |
4) actual formation gas CH, is calculated using the inversion formula that the present invention obtains4、CO2Effecive porosity.It should
Formula is as follows:
In formula, φ ab, N2The shale absolute porosity that inverting obtains when measuring for nitrogen, is calculated by following formula,
Wherein φadsIt is calculated by the formula:
In formula,The hole measured for nitrogen
Porosity in other words shale to the effecive porosity of nitrogen.
Used other parameters are equally as shown in table 5 in the present embodiment calculating process, and table 11 is that the present invention calculates data
With experimental determination data comparison table, and will comparing result converge with Fig. 4 in, wherein the experimental determination data in table 11 are originated from
Aljamaan H.M.,Experimental investigation of shale physical and transport
properties.A Report Submitted to the Department of Energy Resources
Engineering of Stanford University, 2013, and the experimental data is using pulse attenuation method (Brace
W.F.,Walsh J.B.Frangos W.T.,Permeability of granite under high pressure,
Journal of Geophysical Research, 1968,173:2225-2236) obtain.
Table 11
| Porosity | Directly use N2It surveys | Experimental data | The present invention calculates data |
| CH4Monolayer adsorption effecive porosity | 0.06 | 0.108 | 0.1084 |
| CO2Multilayer adsorbs effecive porosity | 0.06 | 0.28 | 0.2796 |
Calculated result of the present invention is almost the same with laboratory measurements as can be seen from the comparison result, illustrates with this hair
It is bright inverting to be carried out to shale gas reservoir gas gaging hole porosity, and computational accuracy is higher.
Claims (9)
1. a kind of shale gas reservoir gas effecive porosity inversion method comprising following steps:
(1), according to mass conservation law, the shale effecive porosity inversion formula for considering adsorbed gas and free gas is established；
(2), shale gas reservoir absolute porosity is measured using helium, obtains helium measurement absolute porosity, it is exhausted in helium measurement
Practical shale is obtained respectively to the effecive porosity of methane and carbon dioxide to inverting on the basis of porosity；
Or the effecive porosity of nitrogen measurement is obtained, at this to the effecive porosity of nitrogen using nitrogen measurement shale gas reservoir
Inverting obtains shale absolute porosity on the basis of nitrogen measurement effecive porosity, then obtains reality by the absolute porosity inverting
Shale is respectively to the effecive porosity of methane and carbon dioxide；
Shown in such as following formula (15) of shale effecive porosity inversion formula described in step (1)；
φe=φab(1+f)(15)；
In formula (15), φ e is effecive porosity of the gas in shale, and φ ab is the absolute hole of shale that helium gas surveys that method measures
Degree or nitrogen gas survey the obtained shale absolute porosity of method inverting, and f is methane or carbon dioxide effecive porosity correction factor,
Wherein, f is calculated by following formula (14):
In formula (14), ρadsTo adsorb air tightness, ρgFor eudiometry density, φ ads is shale adsorbed gas porosity.
2. the method according to claim 1, wherein step passes through the inverting in (2) when being measured using helium
Obtained helium measure absolute porosity to practical shale respectively to the inversion formula of methane and carbon dioxide effecive porosity such as
Shown in following formula (28)；
In formula (28), φ ab, He are the absolute porosity of helium measurement, ρrFor rock density, ρadsTo adsorb air tightness, VLFor list
Layer saturation adsorption volume,For mole, p is shale gas reservoir pressure, BgFor gas volume factor, Z be gas compression because
Son, R are Avgadro constant, and T is temperature, and ξ is the ratio between adsorbed gas and free air tightness, and usual value is 1.8-2.5, and C is
Related constant, p are adsorbed with net heat0It is saturated adsorptive pressure for gas, N is the absorption number of plies.
3. according to the method described in claim 2, it is characterized in that, when being measured using helium, effective hole of actual formation gas i
Porosity inversion formula are as follows:
φi,e=φab,He(1+fi,He) (16)；
In formula (16), actual formation effecive porosity correction factor are as follows:
In formula (17), gas density expresses formula are as follows:
ρads=ξ ρg(22)；
In formula (22), ξ=aebp；Wherein, a, b are adsorbed gas bulkfactor, and related with gas type, rock forming mineral, p is shale
Gas reservoir pressure；
When considering multilayer absorption, adsorption layer gas volume calculates formula:
In formula (23), VbulkFor shale sillar volume；
Thus adsorption layer gaseous porosity is obtained:
By intermediate variable GaIt is brought into adsorption layer gaseous porosity formula:
The effecive porosity correction factor expression formula of actual formation gas i when thus obtaining measuring porosity using helium:
By formula (27) substitute into formula (16), obtain helium measurement porosity to actual formation gas i effecive porosity inverting public affairs
Formula:
Wherein, the actual formation gas i is methane or carbon dioxide.
4. the method according to claim 1, wherein shale described in step (2) is absolute when being measured using nitrogen
Porosity is calculated by following formula (37),
In formula (37), φAb, N2Absolute porosity, φ are measured for nitrogena,N2Shale gas reservoir is to nitrogen when to be measured using nitrogen
Effecive porosity, ξ are the ratio between adsorbed gas and free air tightness, and usual value is 1.8-2.5, ρrFor rock density, VLIt is full for single layer
And adsorption volume,For mole, p is shale gas reservoir pressure, BgFor gas volume factor, C is related with net hot absorption
Constant, p0It is saturated adsorptive pressure for gas, N is the absorption number of plies, ρadsTo adsorb air tightness, Z is Gas Compression Factor, R be Ah
Fu Jiadeluo constant, T are temperature.
5. method according to claim 1 or 4, which is characterized in that when using nitrogen measurement, by described in step (2)
Absolute porosity inverting obtains practical shale respectively to the inversion formula such as following formula of the effecive porosity of methane and carbon dioxide
(39) shown in；
In formula (39), φi,eIt is shale to methane or carbon dioxide effecive porosity, φ ab, N2Shale gas reservoir when being measured for nitrogen
Absolute porosity, ξ are the ratio between adsorbed gas and free air tightness, and usual value is 1.8-2.5, φadsSpiracular slit is adsorbed for shale
Degree.
6. the method according to claim 1, wherein this method further includes in different pressures when being measured using helium
Analytical unit quality shale CH is distinguished under power4And CO2The operation of adsorbance.
7. according to the method described in claim 6, it is characterized in that, the pressure is 0-5 × 106MPa。
8. the method according to claim 1, wherein this method further includes in different pressures when being measured using nitrogen
Analytical unit quality shale N is distinguished under power2、CH4And CO2The operation of adsorbance.
9. according to the method described in claim 8, it is characterized in that, the pressure is 0-5 × 106MPa。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710095343.4A CN106932323B (en) | 2017-02-22 | 2017-02-22 | A kind of shale gas reservoir gas effecive porosity inversion method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710095343.4A CN106932323B (en) | 2017-02-22 | 2017-02-22 | A kind of shale gas reservoir gas effecive porosity inversion method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106932323A CN106932323A (en) | 2017-07-07 |
| CN106932323B true CN106932323B (en) | 2019-05-14 |
Family
ID=59423410
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710095343.4A Active CN106932323B (en) | 2017-02-22 | 2017-02-22 | A kind of shale gas reservoir gas effecive porosity inversion method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106932323B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108226003B (en) * | 2017-12-14 | 2020-04-03 | 河海大学 | Calculation method of stratum adsorption retardation factor |
| CN108132207B (en) * | 2018-02-09 | 2020-05-15 | 辽宁翔舜科技有限公司 | Front peak identification technical method for coke pore structure detection |
| FR3085073B1 (en) * | 2018-08-16 | 2020-08-07 | Ifp Energies Now | PROCESS FOR DETERMINING A QUANTITY OF GAS ADSORBED IN A POROUS MEDIUM |
| CN109799176B (en) * | 2019-01-21 | 2020-08-14 | 清华大学 | Analysis method for accurately measuring adsorption of gas in porous material pore channel |
| CN110927041B (en) * | 2019-12-09 | 2021-01-29 | 山东大学 | Tomography method for representing permeability characteristics of fractured rock |
| CN112113881B (en) * | 2020-09-01 | 2021-05-07 | 中国矿业大学(北京) | Density measuring method for adsorptive methane in coal |
| CN112304842B (en) * | 2020-09-25 | 2021-07-27 | 西南石油大学 | Shale oil CO2/N2Alternating displacement injection quantity simulation analysis method |
| CN113984625B (en) * | 2021-10-29 | 2024-04-09 | 西南石油大学 | Device for measuring porosity of shale reservoir |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2323556A (en) * | 1940-11-29 | 1943-07-06 | Phillips Petroleum Co | Method and apparatus for determining effective porosity |
| CN103439238A (en) * | 2013-09-03 | 2013-12-11 | 中国地质大学（北京） | Measurement method of storage porosity in coal shale |
-
2017
- 2017-02-22 CN CN201710095343.4A patent/CN106932323B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2323556A (en) * | 1940-11-29 | 1943-07-06 | Phillips Petroleum Co | Method and apparatus for determining effective porosity |
| CN103439238A (en) * | 2013-09-03 | 2013-12-11 | 中国地质大学（北京） | Measurement method of storage porosity in coal shale |
Non-Patent Citations (3)
| Title |
|---|
| How to Correct the Petro-Physical Properties for Simulating Shale Gas Production Using Current Commercial Simulators?;J.Wang 等;《SPE Annual Technical Conference and Exhibition》;Society of Petroleum Engineers;20161231;第1-17页 |
| Influences of adsorption/desorption of shale gas on the apparent properties of matrix pores;Wang Jing 等;《Petroleum Exploration and Development》;20160229;第43卷(第1期);第158-166页 |
| Variations of Gas Flow Regimes and Petro-Physical Properties During Gas Production Considering Volume Consumed by Adsorbed Gas and Stress Dependence Effect in Shale Gas Reservoirs;J.Wang 等;《SPE Annual Technical Conference and Exhibition》;Society of Petroleum Engineers;20151231;第1-35页 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106932323A (en) | 2017-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106932323B (en) | A kind of shale gas reservoir gas effecive porosity inversion method | |
| CN108518212B (en) | Method for calculating unsteady state yield of shale gas reservoir complex fracture network | |
| CN105910971B (en) | The simultaneous measuring method of rich organic matter compact rock core gas permeability and diffusion coefficient | |
| Clarkson et al. | Predicting sorption-induced strain and permeability increase with depletion for coalbed-methane reservoirs | |
| CN104677771B (en) | A method of shale porosity is determined based on magnetic suspension gravimetric method | |
| CN106547966B (en) | A kind of shale oil adsorbance with can momentum evaluation model and its foundation, application method | |
| Aljamaan et al. | In-depth experimental investigation of shale physical and transport properties | |
| CN104374683A (en) | Device and method for testing core pore compressibility | |
| Zhou et al. | Evolution of coal permeability with cleat deformation and variable Klinkenberg effect | |
| Lin et al. | Gas sorption and the consequent volumetric and permeability change of coal I: experimental | |
| CN105842416B (en) | A kind of shale adsorbed gas content Dynamic calculation method based on Langmuir model | |
| Dong et al. | Permeabilities of tight reservoir cores determined for gaseous and liquid CO2 and C2H6 using minimum backpressure method | |
| CN106290057A (en) | The assay method of shale absorption tolerance | |
| Zhao et al. | Fractal characterization of pore structure for coal macrolithotypes in the Hancheng area, southeastern Ordos Basin, China | |
| CN106290061A (en) | The method measuring Adsorbate Gas absorption phase density in adsorbate | |
| CN104297126A (en) | Device and method applied to measurement of low-permeability reservoir gas seepage start-up pressure gradient | |
| Zhong et al. | Experimental and numerical analyses of apparent gas diffusion coefficient in gas shales | |
| CN109580454B (en) | Method for testing fluid sensitivity of tight reservoir by using pressure oscillation method | |
| CN105628575B (en) | Shale property assay method, device and shale property analyzer | |
| Yang et al. | Experimental investigation about gas transport in tight shales: an improved relationship between gas slippage and petrophysical properties | |
| Zhou et al. | Predicting adsorbed gas capacity of deep shales under high temperature and pressure: Experiments and modeling. | |
| Wang et al. | Seepage law and permeability calculation of coal gas based on Klinkenberg effect | |
| CN106897531A (en) | A kind of method for quantitatively evaluating of hyposmosis limestone reservoir permeability | |
| Wang et al. | A novel permeability prediction model for coal based on dynamic transformation of pores in multiple scales | |
| Mahmoud | Effect of gas adsorption on the estimation of gas in place (GIP) in conventional and unconventional reservoirs |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |