CN108710765B - It is a kind of to consider multifactor shale gas reservoir gross reserves calculation method - Google Patents
It is a kind of to consider multifactor shale gas reservoir gross reserves calculation method Download PDFInfo
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- 238000004364 calculation method Methods 0.000 title claims abstract description 14
- 239000011159 matrix material Substances 0.000 claims abstract description 77
- 238000010521 absorption reaction Methods 0.000 claims abstract description 57
- 238000001179 sorption measurement Methods 0.000 claims abstract description 26
- 238000003795 desorption Methods 0.000 claims abstract description 18
- 230000000694 effects Effects 0.000 claims abstract description 6
- 239000007789 gas Substances 0.000 claims description 220
- 239000011435 rock Substances 0.000 claims description 95
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 51
- 230000015572 biosynthetic process Effects 0.000 claims description 36
- 239000005416 organic matter Substances 0.000 claims description 30
- 230000000274 adsorptive effect Effects 0.000 claims description 21
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 21
- 230000008961 swelling Effects 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 13
- 230000001186 cumulative effect Effects 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 239000003345 natural gas Substances 0.000 claims description 9
- 230000008859 change Effects 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 3
- 238000003860 storage Methods 0.000 claims description 2
- 239000000047 product Substances 0.000 claims 3
- 239000003463 adsorbent Substances 0.000 claims 1
- 238000004090 dissolution Methods 0.000 claims 1
- 239000012265 solid product Substances 0.000 claims 1
- 239000011148 porous material Substances 0.000 description 6
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 102000003712 Complement factor B Human genes 0.000 description 2
- 108090000056 Complement factor B Proteins 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
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- 238000007906 compression Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Abstract
The present invention, which discloses, a kind of considers multifactor shale gas reservoir gross reserves calculation method, comprising the following steps: test, the basic parameter and creation data for collecting shale gas reservoir；Consider that crack free gas, absorption phase porosity, the variation of absorption phase volume, adsorbed gas critical desorption pressures and adsorbed gas desorb the blockage effect generated to matrix, and multi component adsorption and solution gas are considered simultaneously, shale gas reservoir matter balance equation is established, shale gas reservoir gross reserves equation is finally obtained；The basic parameter and creation data of shale gas reservoir are handled according to the matter balance equation of foundation, and draw correlation curve；Shale gas reservoir gross reserves G is finally calculatedt.The present invention has comprehensively considered multi component adsorption and solution gas, crack free gas, absorption phase porosity, the variation of absorption phase volume, adsorbed gas critical desorption pressures and adsorbed gas desorb the blockage effect generated to matrix, new shale gas reservoir matter balance equation is established, the equation has great importance to reasonable computation shale gas reservoir dynamic holdup.
Description
Technical field
Multifactor shale gas reservoir gross reserves calculation method is considered the present invention relates to a kind of.
Background technique
Shale gas is a kind of Unconventional gas, mainly with free state, ADSORPTION STATE and a small amount of solubilised state preservation in shale gas
In hiding, wherein adsorbed gas content is typically in the range of between 20%~85%, dissolves Gas content generally 5% or so, this makes its storage
Amount calculation method is different from normal gas pools.Usual shale gas Reserve Estimation Method has 3 kinds: analogy method, volumetric method and material balance
Method.
Analogy method is mainly used for exploration initial stage and evaluates shale gas reservoir oil in place roughly, and Zhang Jinhua etc., Li Hongxun etc. are respectively
Propose the applicable elements of analogy method.Volumetric method is suitable for calculating shale gas reservoir static state oil in place, Xu Haixia etc., Chen Yuanqian etc.
The calculation method of shale gas reservoir oil in place is proposed, but does not consider the porosity that absorption mutually occupies.Ambrose etc., which is established, to be examined
Consider absorption phase porosity shale gas reservoir reserves computation model, but the model does not consider multi component adsorption and solution gas.Cao Yankuan etc.,
Though Qu Zhanqing etc. has studied the shale gas reservoir reserves for considering multi component adsorption, the reserves of solution gas are not considered.Jiang Ruizhong et al.
Shale gas reserves calculation formula has been derived from molecule angle, but also only considered the absorption phase reserves of single methane molecule composition.
Material balance method, which is commonly used to calculate shale gas reservoir, employs oil in place, and when calculating needs mass production data, and numerous scholars are adopting
When calculating shale gas reservoir reserves with matter balance equation, the solution gas not being dissolved in kerogen is taken into account, and causes to calculate
As a result inaccurate.
Summary of the invention
The present invention mainly overcomes shortcoming in the prior art, and it is multifactor to propose that a kind of calculating more accurately considers
Shale gas reservoir gross reserves calculation method.
The present invention solves technical solution provided by above-mentioned technical problem: a kind of to consider that multifactor shale gas reservoir always stores up
Measure calculation method, comprising the following steps:
Step S100, test, collect shale gas reservoir basic parameter and gas reservoir creation data；
Step S200, consider crack free gas, absorption phase porosity, the variation of absorption phase volume, adsorbed gas critical index suction pressure
Power and adsorbed gas desorb the blockage effect generated to matrix, amendment rock compressibility, and consider simultaneously multi component adsorption and
Solution gas establishes shale gas reservoir matter balance equation:
In formula: GpFor cumulative gas, unit 108m3；GmIt is for free gas reserves, unit in Rock Matrix
108m3；GfFor free gas reserves in crack rock, unit 108m3；BgGas volume factor when for strata pressure being p,
Unit is m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressed
Coefficient, unit MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit is
MPa-1；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor facing for shale gas
Boundary's desorption pressures, unit MPa；For matrix porosity, unit f；ρbFor rock density, unit g/cm3；
ρsmixTo adsorb phase density, unit g/cm3；ρscFor natural gas density under standard state, unit g/cm3；To inhale
Attached phase apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；yiFor in absorption phase
The molar fraction of i-th component, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；poFor primitively
Stressor layer, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component
Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density,
Unit is g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For the hole of free gas in organic matter
Degree, unit f；
Step S300, Y/X and E/X are obtained according to basic parameter, gas reservoir creation data and shale gas reservoir matter balance equation
Multiple groups value, then be fitted in reference axis the relation curve of Y/X and E/X, the slope of relation curve is to dissociate in Rock Matrix
Gas reserves Gm, intercept is free gas reserves G in crack rockf；
Wherein Y=GpBg, X=Bg-Bgi+BgiccfΔ p,
In formula: GpFor cumulative gas, unit 108m3；BgGas volume factor when for strata pressure being p, list
Position is m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressed system
Number, unit MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit MPa-1；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor the critical of shale gas
Desorption pressures, unit MPa；For matrix porosity, unit f；ρbFor rock density, unit g/cm3；ρsmix
To adsorb phase density, unit g/cm3；ρscFor natural gas density under standard state, unit g/cm3；To adsorb phase
Apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；yiIt is i-th group in absorption phase
The molar fraction divided, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；poTo be primitively laminated
Power, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component Langmuir suction
Enclosure pressure, unit MPa；For the porosity for adsorbing phase in organic matter, unit f；For free gas in organic matter
Porosity, unit f；
Step S400, shale gas reservoir gross reserves is finally obtained:
In formula: GtFor shale gas reservoir gross reserves, unit 108m3；GmFor free gas reserves, unit in Rock Matrix
It is 108m3；GfFor free gas reserves in crack rock, unit 108m3；BgiFor the gas volume system under original formation pressure
Number, unit m3/m3；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；
For matrix porosity, unit f；To adsorb phase apparent porosity, unit f；VLiFor the i-th component Langmuir absorption
Volume, unit m3/t；yiFor the molar fraction of the i-th component in absorption phase, unit f；yjFor jth component in absorption phase
Molar fraction, unit f；poFor original formation pressure, unit MPa；pLiFor the i-th component Langmuir adsorption pressure
Power, unit MPa；pLjFor jth component Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, list
Position is f；ρkoFor kerogenic density, unit g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For the porosity of free gas in organic matter, unit f.
Further technical solution is that the gas reservoir creation data includes multi-group data, and every group of data include strata pressure
P, gas volume factor B when strata pressure is pg, cumulative gas Gp。
Further technical solution is the specific establishment process of the step S200 shale gas reservoir matter balance equation are as follows:
Step S201, the Rock Matrix and irreducible water swelling volume Δ G when strata pressure drops to p are calculatedm:
In formula: Δ GmFor Rock Matrix and irreducible water swelling volume, unit 108m3；GmFor free gas in Rock Matrix
Reserves, unit 108m3；BgiFor the gas volume factor under original formation pressure, unit f；SmiFor matrix irreducible water
Saturation degree, unit f；cxFor modified rock compressibility, unit MPa-1；cwFor the water flooding compressed coefficient, list
Position is MPa-1；poFor original formation pressure, unit MPa；P is strata pressure, unit MPa；
Step S202, the crack rock and irreducible water swelling volume Δ G when strata pressure drops to p are calculatedf:
In formula: Δ GfFor crack rock and irreducible water swelling volume, unit 108m3；GfFor free gas in crack rock
Reserves, unit 108m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；SfiFor crack rock
Irreducible water saturation, unit f；cfFor the crack compressed coefficient, unit MPa-1；cwFor the water flooding compressed coefficient, list
Position is MPa-1；poFor original formation pressure, unit MPa；P is strata pressure, unit MPa；
Step S203, the diffusing capacity Δ G of the solution gas when strata pressure drops to p is calculatedd:
In formula: Δ GdFor the diffusing capacity of solution gas, unit 108m3；GmFor free gas reserves, list in Rock Matrix
Position is 108m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；BgGas when for strata pressure being p
Body volume factor, unit m3/m3；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, list
Position is f；For matrix porosity, unit f；To adsorb phase apparent porosity, unit f；VskFor solid kerogen
Volume, unit 108m3；poFor original formation pressure, unit MPa；ρbFor rock density, unit g/cm3；
CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density, unit g/cm3；To be adsorbed in organic matter
The porosity of phase, unit f；For the porosity of free gas in organic matter, unit f；b2It is -0.85048；b3For
827.26；b4It is -635.26；T is formation temperature, unit K；
Step S204, according to shale gas reservoir reservoir space volume conservation principle, cumulative gas production=Medium Culture free gas is swollen
Free gas expands in swollen volume+Rock Matrix and irreducible water elastic expansion volume+crack rock and irreducible water swelling volume+crack
The solution gas volume spread in volume+adsorbed gas gas desorption quantity+kerogen-absorption phase change volume, then shale gas reservoir substance is flat
Weigh equation are as follows:
In formula: GtFor shale gas reservoir gross reserves, unit 108m3；GmFor free gas reserves, unit in Rock Matrix
It is 108m3；GfFor free gas reserves in crack rock, unit 108m3；BgiFor the gas volume system under original formation pressure
Number, unit f；BgGas volume factor when for strata pressure being p, unit f；cfFor the crack compressed coefficient, unit
For MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cxFor modified rock compressibility, unit MPa-1；ρb
For rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；For matrix porosity, list
Position is f；To adsorb phase apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；
yiFor the molar fraction of i component in absorption phase, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；
poFor original formation pressure, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth
Component Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoIt is kerogenic close
Degree, unit g/cm3；For the porosity of free gas in organic matter, unit f；For the aspiration that dissociates in organic matter
The porosity of attached phase, unit f.
The beneficial effects of the present invention are: the present invention has comprehensively considered multi component adsorption and solution gas, crack free gas, absorption
Phase porosity, the variation of absorption phase volume, adsorbed gas critical desorption pressures and adsorbed gas desorb the blockage effect generated to matrix, repair
Just rock compressibility establishes a kind of new shale gas reservoir matter balance equation, and the equation is for reasonable computation shale gas
Hiding dynamic holdup has great importance.
Detailed description of the invention
Fig. 1 is kerogenic spatial distribution map in organic matter；
Fig. 2 is matter balance equation reserves regression figure.
Specific embodiment
Further description is done to the present invention below with reference to embodiment and attached drawing.
It is of the invention a kind of to consider multifactor shale gas reservoir gross reserves calculation method, comprising the following steps:
Step S100, test, collect shale gas reservoir basic parameter and gas reservoir creation data；The gas reservoir creation data packet
Include multi-group data, the gas volume factor B that every group of data include strata pressure p, strata pressure when being pg, cumulative gas Gp。
Step S200, consider crack free gas, absorption phase porosity, the variation of absorption phase volume, adsorbed gas critical index suction pressure
Power and adsorbed gas desorb the blockage effect generated to matrix, amendment rock compressibility, and consider simultaneously multi component adsorption and
Solution gas establishes shale gas reservoir matter balance equation:
In formula: GpFor cumulative gas, unit 108m3；GmIt is for free gas reserves, unit in Rock Matrix
108m3；GfFor free gas reserves in crack rock, unit 108m3；BgGas volume factor when for strata pressure being p,
Unit is m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressed
Coefficient, unit MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit is
MPa-1；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor facing for shale gas
Boundary's desorption pressures, unit MPa；For matrix porosity, unit f；ρbFor rock density, unit g/cm3；
ρsmixTo adsorb phase density, unit g/cm3；ρscFor natural gas density under standard state, unit g/cm3；To inhale
Attached phase apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；yiFor i in absorption phase
The molar fraction of component, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；poFor prime stratum
Pressure, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component Langmuir
Adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density, unit g/
cm3；For the porosity of free gas in organic matter, unit f；For in organic matter dissociate the attached phase of aspiration porosity,
Its unit is f；
Step S300, Y/X and E/X are obtained according to basic parameter, gas reservoir creation data and shale gas reservoir matter balance equation
Multiple groups value, then be fitted in reference axis the relation curve of Y/X and E/X, the slope of relation curve is to dissociate in Rock Matrix
Gas reserves Gm, intercept is free gas reserves G in crack rockf；
Wherein Y=GpBg, X=Bg-Bgi+BgiccfΔ p,
In formula: GpFor cumulative gas, unit 108m3；BgGas volume factor when for strata pressure being p, list
Position is m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressed system
Number, unit MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit MPa-1；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor the critical of shale gas
Desorption pressures, unit MPa；For matrix porosity, unit f；ρbFor rock density, unit g/cm3；ρsmix
To adsorb phase density, unit g/cm3；ρscFor natural gas density under standard state, unit g/cm3；To adsorb phase
Apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；yiFor i component in absorption phase
Molar fraction, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；poFor original formation pressure,
Its unit is MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component Langmuir absorption
Pressure, unit MPa；For the porosity for the attached phase of aspiration of dissociating in organic matter, unit f；
Step S400, shale gas reservoir gross reserves equation is finally obtained:
In formula: GtFor shale gas reservoir gross reserves, unit 108m3；GmFor free gas reserves, unit in Rock Matrix
It is 108m3；GfFor free gas reserves in crack rock, unit 108m3；BgiFor the gas volume system under original formation pressure
Number, unit m3/m3；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；
For matrix porosity, unit f；To adsorb phase apparent porosity, unit f；VLiFor the i-th component Langmuir absorption
Volume, unit m3/t；yiFor the molar fraction of i component in absorption phase, unit f；poFor original formation pressure, list
Position is MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component Langmuir adsorptive pressure,
Its unit is MPa；CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density, unit g/cm3；For
The porosity of free gas in organic matter, unit f；For the porosity for the attached phase of aspiration of dissociating in organic matter, unit f.
The wherein specific establishment process of step S200 are as follows:
Shale gas one-component adsorption mechanism is similar to coal bed gas, calculates adsorbed gas frequently with Langmuir adsorption isotherm
Amount, however usually not containing only one-component methane in practical shale reservoir absorption phase, there is also other gases such as ethane and propane
Absorption, therefore should be using the Langmuir adsorption isotherm of extension, then when calculating shale gas absorption tolerance:
In shale reservoir, due to not flowing for binding molecule layer, so that the spiracular slit degree that dissociates in matrix is than practical matrix hole
Porosity is small, and absorption phase apparent porosity is defined as
Then matrix volume is
Matrix pores volume VpFor
Adsorbed gas volume is under surface condition
The critical desorption pressures for considering shale gas are pd, then when strata pressure drops to p, adsorbed gas gas desorption quantity is
Then the volume of absorption phase is under formation condition
Therefore when strata pressure drops to p, absorption phase volume knots modification is
Since reservoir pressure and temperature are all much higher than the critical pressure and critical-temperature of adsorbed gas each component, make it difficult to really
Determine to adsorb in reservoir is mutually the quasi- critical pressure that multi component adsorption gas is sought with liquid or gaseous form presence and quasi- stagnation temperature
Degree, then be by the density that van der Waals equation finds out absorption phase
Bring formula (3) and formula (7) into formula (2), then the apparent porosity for adsorbing phase is
When strata pressure drops to critical desorption pressures, adsorbed gas starts to desorb, and desorption receives shale matrix
Compression deformation, can obtain matrix deformation degree using the Langmuir adsorption isotherm of Bangham solid deformation theory and extension is
With the output of gas, effective stress increases, and Rock Matrix is squeezed deformation, then rock elasticity expands deformation quantity
For
ΔεN=cm(po-p) (12)
The total deformation quantity of shale matrix is equal to rock elasticity caused by desorbing caused matrix deformation quantity and effective stress increase
Expand the sum of deformation quantity, it may be assumed that
Using the propositions such as Seidle porosity and matrix deformation quantity relationship, then deformed matrix porosity be
It is based on the rock compressibility that pore volume defines
The rock compressibility defined based on rock apparent volume and the rock compressibility that is defined based on pore volume
Relationship are as follows:
Joint type (14), formula (15) and formula (16) can obtain:
When strata pressure drops to p, Rock Matrix and irreducible water swelling volume are
When strata pressure drops to p, crack rock and irreducible water swelling volume are
Many scholars think that dissolve Gas content does not account for very little when calculating shale gas reserves, and Swami etc. is ground
Studying carefully the solution gas in discovery solid-state kerogen is also an important component for being also shale gas reserves.If without considering,
Meeting is so that shale gas reserves calculated result generates large error.
Kerogen is present in organic matter, organic matter spatial distribution as shown in Figure 1, then total kerogen in organic matter
Occupy the volume fraction V of gas reservoir volumetkerFor
Therefore
Wherein, VtkerCalculation method be
Therefore, VdiffIt is also denoted as
Then the kerogenic volume of solid-state is
Calculating solubility of the natural gas in kerogen using empirical equation is
In formula: b1=-0.018931；b2=-0.85048；b3=827.26；b4=-635.26.
Solution gas inplace is in solid-state kerogen
Then when strata pressure drops to p, the diffusing capacity of solution gas is
According to shale gas reservoir reservoir space volume conservation principle, cumulative gas production=Medium Culture free gas swelling volume+rock
Free gas swelling volume+absorption in ground mass matter and irreducible water elastic expansion volume+crack rock and irreducible water swelling volume+crack
The solution gas volume spread in gas gas desorption quantity+kerogen-absorption phase change volume, then shale gas reservoir matter balance equation be
It enables
Bring formula (29) abbreviation into:
It enables: Y=GpBg, X=Bg-Bgi+BgiccfΔ P,
Then formula (30) can be with abbreviation
Y=EGm+XGf (31)
Both ends can be obtained divided by X simultaneously:
Formula (32) is the linear equation of material balance of multi component adsorption and solution gas the considerations of derivation, utilizes creation data
It can be fitted the linear relationship of Y/X and E/X, the intercept of curve is the reserves of free gas in crack, and slope of a curve is rock
The reserves of free gas in matrix, then shale gas reservoir gross reserves be
Above-mentioned symbol are as follows:
P --- strata pressure, MPa；
VE--- the isothermal adsorption amount under strata pressure, m3/t；
VLi--- the i-th component Langmuir adsorption volume, m3/t；
pLi--- the i-th component Langmuir adsorptive pressure, MPa；
pLj--- jth component Langmuir adsorptive pressure, MPa；
N --- the gas kind number of absorption phase；
yi--- the molar fraction of i component, f in absorption phase；
yj--- the molar fraction of j component, f in absorption phase；
--- absorption phase apparent porosity, f；
Va--- adsorb phase volume under formation condition, 108m3；
Vm--- matrix volume, 108m3；
Gm--- free gas reserves in matrix, 108m3；
Bgi--- the gas volume factor under original formation pressure, m3/m3；
Smi--- matrix irreducible water saturation, f；
--- matrix porosity, f；
Vp--- matrix pores volume, 108m3；
Gas--- adsorbed gas volume under surface condition, 108m3；
ρb--- rock density, g/cm3；
po--- original formation pressure, MPa；
Gde--- adsorbed gas gas desorption quantity when strata pressure is p, 108m3；
Bg--- gas volume factor when strata pressure is p, f；
pd--- the critical desorption pressures of shale gas, MPa；
ΔVa--- absorption phase volume knots modification, 108m3；
ρsmix--- absorption phase density, g/cm3；
ρsc--- natural gas density under standard state, g/cm3；
M --- gas molar quality, g/mol；
--- absorption phase average molal weight, g/mol；
pc--- gas critical pressure, MPa；
ppc--- critical pressure, MPa are mutually intended in absorption；
Tc--- gas critical-temperature, K；
Tpc--- absorption phase pseudo-critical temperature, K；
R --- gas constant takes 8.314J/molK；
Δ ε --- adsorbed gas desorbs the deformation extent caused by matrix, f；
Vmol--- molar volume of gas；m3/kmol；
E --- Young's modulus, MPa；
ΔεN--- rock elasticity expands deformation quantity, f；
cm--- rock compressibility, MPa-1；
Δεt--- the total deformation quantity of matrix, f；
--- deformed matrix porosity, f；
cxp--- based on the rock compressibility that pore volume defines, MPa-1；
cx--- modified rock compressibility, MPa-1；
ΔVp--- pore volume change, 108m3；
Δ p --- strata pressure variable quantity, MPa；
ΔGm--- Rock Matrix and irreducible water swelling volume, 108m3；
ΔGf--- crack rock and irreducible water swelling volume, 108m3；
cw--- the water flooding compressed coefficient, MPa-1；
cf--- the crack compressed coefficient, MPa-1；
Vtker--- total kerogen occupies the volume fraction of gas reservoir volume, f in organic matter；
Vdiff--- solid-state kerogen accounts for the volume fraction of gas reservoir total volume, f；
--- the porosity for the attached phase of aspiration of dissociating in organic matter, f；
CTO--- total content of organic carbon, f；
ρr--- kerogenic relative density；
ρko--- kerogenic density, g/cm3；
Vsk--- the kerogenic volume of solid-state, 108m3；
ΔGd--- the diffusing capacity of solution gas, 108m3。
Embodiment
The basic parameter of Fuling shale gas reservoir is as follows: po=36.49MPa, Bgi=0.0035, Smi=0.3, Cm=9.182
×10-4MPa-1, Sfi=0.04, Cf=9.151 × 10-3MPa-1, Cw=4.629 × 10-4MPa-1, ρb=2.53g/cm3,=
0.05, T=355.15K, CTO=3.81%,=0.0019,=0.04, ρko=1.325g/cm3, Young's modulus takes
26800MPa, natural gas density takes 77000g/cm under standard state3, critical desorption pressures pd=35.49MPa.Other are basic
Parameter is as shown in table 1, and creation data is as shown in table 2.
The basic parameters such as 1 shale gas reservoir each component Langmuir value of table and thermodynamics
2 creation data of table
Using above data, gas pool reserve recurrence is carried out using the matter balance equation derived herein, as a result such as Fig. 2 and table
3。
3 distinct methods comparison of computational results of table
The above is not intended to limit the present invention in any form, although the present invention takes off through the foregoing embodiment
Show, however, it is not intended to limit the invention, any person skilled in the art, is not departing from technical solution of the present invention range
It is interior, made when the technology contents using the disclosure above and change or be modified to the equivalent embodiments of equivalent variations a bit, but it is all not
Be detached from technical solution of the present invention content, according to the technical essence of the invention it is to the above embodiments it is any it is simple modification,
Equivalent variations and modification, all of which are still within the scope of the technical scheme of the invention.
Claims (3)
1. a kind of consider multifactor shale gas reservoir gross reserves calculation method, which comprises the following steps:
Step S100, test, collect shale gas reservoir basic parameter and gas reservoir creation data；
Step S200, consider crack free gas, absorption phase porosity, absorption phase volume variation, adsorbed gas critical desorption pressures and
Adsorbed gas desorbs the blockage effect generated to matrix, corrects rock compressibility, and consider multi component adsorption and dissolution simultaneously
Gas establishes shale gas reservoir matter balance equation:
In formula: GpFor cumulative gas, unit 108m3；GmFor free gas reserves in Rock Matrix, unit 108m3；Gf
For free gas reserves in crack rock, unit 108m3；BgGas volume factor when for strata pressure being p, unit are
m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressibility,
Unit is MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit MPa-1；ρbFor
Rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor the critical index suction pressure of shale gas
Power, unit MPa；For matrix porosity, unit f；ρsmixTo adsorb phase density, unit g/cm3；ρscFor mark
Natural gas density under quasi- state, unit g/cm3；To adsorb phase apparent porosity, unit f；VLiFor the i-th component
Langmuir adsorption volume, unit m3/t；yiFor the molar fraction of i component in absorption phase, unit f；poFor primitively
Stressor layer, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth component
Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density,
Unit is g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For the hole of free gas in organic matter
Degree, unit f；SfiFor crack rock irreducible water saturation, unit f；b2It is -0.85048；b3It is 827.26；b4For-
635.26；T for stratum temperature, unit K；
Step S300, Y/X and E/X are obtained according to basic parameter, gas reservoir creation data and shale gas reservoir matter balance equation more
Class value, then it is fitted in reference axis the relation curve of Y/X and E/X, the slope of relation curve is free gas storage in Rock Matrix
Measure Gm, intercept is free gas reserves G in crack rockf；
Wherein Y=GpBg, X=Bg-Bgi+BgiccfΔ p,
In formula: GpFor cumulative gas, unit 108m3；BgGas volume factor when for strata pressure being p, unit are
m3/m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；cxFor modified rock compressibility,
Unit is MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cfFor the crack compressed coefficient, unit MPa-1；ρbFor
Rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；pdFor the critical index suction pressure of shale gas
Power, unit MPa；For matrix porosity, unit f；ρsmixTo adsorb phase density, unit g/cm3；ρscFor mark
Natural gas density under quasi- state, unit g/cm3；To adsorb phase apparent porosity, unit f；VLiFor the i-th component
Langmuir adsorption volume, unit m3/t；yiFor the molar fraction of i component in absorption phase, unit f；yjTo adsorb phase
The molar fraction of middle jth component, unit f；poFor original formation pressure, unit MPa；pLiFor the i-th component
Langmuir adsorptive pressure, unit MPa；pLjFor jth component Langmuir adsorptive pressure, unit MPa；To have
The porosity of phase, unit f are adsorbed in machine matter；For the porosity of free gas in organic matter, unit f；SfiTo split
Stitch rock irreducible water saturation, unit f；
Step S400, shale gas reservoir gross reserves equation is finally obtained:
In formula: GtFor shale gas reservoir gross reserves, unit 108m3；GmIt is for free gas reserves, unit in Rock Matrix
108m3；GfFor free gas reserves in crack rock, unit 108m3；BgiFor the gas volume factor under original formation pressure,
Its unit is m3/m3；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；For
Matrix porosity, unit f；To adsorb phase apparent porosity, unit f；VLiFor the i-th component Langmuir adsorbent
Product, unit m3/t；yiFor the molar fraction of i component in absorption phase, unit f；yjIt rubs for jth component in absorption phase
That score, unit f；poFor original formation pressure, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure,
Unit is MPa；pLjFor jth component Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit is
f；ρkoFor kerogenic density, unit g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For
The porosity of free gas in organic matter, unit f.
2. a kind of multifactor shale gas reservoir gross reserves calculation method is considered according to claim 1, which is characterized in that institute
Stating gas reservoir creation data includes multi-group data, every group of data include strata pressure p, strata pressure be p when gas volume factor
Bg, cumulative gas Gp。
3. a kind of multifactor shale gas reservoir gross reserves calculation method is considered according to claim 2, which is characterized in that institute
State the specific establishment process of step S200 shale gas reservoir matter balance equation are as follows:
Step S201, the Rock Matrix and irreducible water swelling volume Δ G when strata pressure drops to p are calculatedm:
In formula: Δ GmFor Rock Matrix and irreducible water swelling volume, unit 108m3；GmFor free gas reserves in Rock Matrix,
Its unit is 108m3；BgiFor the gas volume factor under original formation pressure, unit f；SmiWater saturation is fettered for matrix
Degree, unit f；cxFor modified rock compressibility, unit MPa-1；cwFor the water flooding compressed coefficient, unit is
MPa-1；poFor original formation pressure, unit MPa；P is strata pressure, unit MPa；
Step S202, the crack rock and irreducible water swelling volume Δ G when strata pressure drops to p are calculatedf:
In formula: Δ GfFor crack rock and irreducible water swelling volume, unit 108m3；GfFor free gas reserves in crack rock,
Its unit is 108m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；SfiFor crack rock constraint
Water saturation, unit f；cfFor the crack compressed coefficient, unit MPa-1；cwFor the water flooding compressed coefficient, unit is
MPa-1；poFor original formation pressure, unit MPa；P is strata pressure, unit MPa；
Step S203, the diffusing capacity Δ G of the solution gas when strata pressure drops to p is calculatedd:
In formula: Δ GdFor the diffusing capacity of solution gas, unit 108m3；GmIt is for free gas reserves, unit in Rock Matrix
108m3；BgiFor the gas volume factor under original formation pressure, unit m3/m3；BgGas body when for strata pressure being p
Product coefficient, unit m3/m3；ρbFor rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit is
f；For matrix porosity, unit f；To adsorb phase apparent porosity, unit f；VskFor the kerogenic body of solid
Product, unit 108m3；poFor original formation pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoFor
Kerogenic density, unit g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For organic matter
The porosity of middle free gas, unit f；b2It is -0.85048；b3It is 827.26；b4It is -635.26；T is formation temperature,
Unit is K；VskFor the kerogenic volume of solid-state, unit 108m3；
Step S204, according to shale gas reservoir reservoir space volume conservation principle, cumulative gas production=Medium Culture free gas expander
Free gas swelling volume in product+Rock Matrix and irreducible water elastic expansion volume+crack rock and irreducible water swelling volume+crack
The solution gas volume spread in+adsorbed gas gas desorption quantity+kerogen-absorption phase change volume, then shale gas reservoir material balance side
Journey are as follows:
In formula: GtFor shale gas reservoir gross reserves, unit 108m3；GmIt is for free gas reserves, unit in Rock Matrix
108m3；GfFor free gas reserves in crack rock, unit 108m3；BgiFor the gas volume factor under original formation pressure,
Its unit is f；BgGas volume factor when for strata pressure being p, unit f；cfFor the crack compressed coefficient, unit is
MPa-1；cwFor the water flooding compressed coefficient, unit MPa-1；cxFor modified rock compressibility, unit MPa-1；ρbFor
Rock density, unit g/cm3；SmiFor matrix irreducible water saturation, unit f；For matrix porosity, unit
For f；To adsorb phase apparent porosity, unit f；VLiFor the i-th component Langmuir adsorption volume, unit m3/t；yi
For the molar fraction of i component in absorption phase, unit f；yjFor the molar fraction of jth component in absorption phase, unit f；po
For original formation pressure, unit MPa；pLiFor the i-th component Langmuir adsorptive pressure, unit MPa；pLjFor jth group
Divide Langmuir adsorptive pressure, unit MPa；CTOFor total content of organic carbon, unit f；ρkoFor kerogenic density,
Its unit is g/cm3；For the porosity for adsorbing phase in organic matter, unit f；For the hole of free gas in organic matter
Degree, unit f.
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