CN105717016B - A kind of calculation method of coal sample permeability - Google Patents
A kind of calculation method of coal sample permeability Download PDFInfo
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- CN105717016B CN105717016B CN201410741384.2A CN201410741384A CN105717016B CN 105717016 B CN105717016 B CN 105717016B CN 201410741384 A CN201410741384 A CN 201410741384A CN 105717016 B CN105717016 B CN 105717016B
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Abstract
The invention discloses a kind of calculation methods of coal sample permeability, belong to coal-bed gas exploitation field.The described method includes: being pre-processed to coal sample；First time CT scan is carried out to pretreated coal sample has been carried out, obtains first time scanning result；Coal sample original permeability is calculated according to first time scanning result；Phase transformation processing is carried out to coal sample；Second of CT scan is carried out to phase transformation treated coal sample, obtains second of scanning result；According to second of scanning result, to coal sample, in a disguised form rear permeability is calculated；To the coal sample original permeability and coal sample being calculated, in a disguised form rear permeability is compared, and obtains permeability variation multiple.The present invention is by carrying out CT scan to coal sample, then analytical calculation is carried out by result of the three-dimensional imaging software to CT scan, to calculate coal sample permeability, it can not have to be limited during testing coal sample permeability by the permeability of coal sample, the coal sample of permeability arbitrary size can be measured.
Description
Technical field
The present invention relates to coal-bed gas exploitation field, in particular to a kind of calculation method of coal sample permeability.
Background technique
Coal bed gas, refer to be stored in coal seam using methane as main component, to be adsorbed on based on matrix of coal particle surface, portion
Divide the hydrocarbon gas for being free in coal hole or being dissolved in coal seam water, be the associated minerals resource of coal, belongs to Unconventional gas.
Permeability is the measurement of coal seam osmotic fluid capacity of water, the rock core gas according to the experience with mining of existing coal bed gas, in coal seam
When body permeability and bigger equivalent liquid permeability, more coal bed gas can be just produced.But in general, coal seam
Gas Permeability of Cores and equivalent liquid permeability are lower, therefore under the coal seam of original permeability, be can not produce it is more
Few coal bed gas.
For the exploitation being well on to coal bed gas, it is therefore desirable to study the permeability in coal seam, for example pass through reality
It tests to study and can be changed to the permeability in coal seam, common laboratory facilities are to carry out phase transformation processing to coal sample, in coal sample
In be passed through gas or water to measure to the permeability of coal sample, then as far as possible by the liquid in coal sample from liquid condition
It is transformed to solid state, temperature is then reverted into room temperature, the change of the permeability of coal sample before and after the processing in phase transformation is recorded with this
Change, to provide help to the follow-up study of the exploitation of coal bed gas.
In the implementation of the present invention, the inventor finds that the existing technology has at least the following problems:
During measuring under normal conditions to the permeability of coal sample, coal seam lesser for certain permeabilities is come
It says, due to the limitation of the coal sample in these coal seams permeability itself, during the test, the water or gas for being passed through coal sample can not be from
It is infiltrated in coal sample, so the permeability in the lesser coal seam of these permeabilities cannot be obtained.
Summary of the invention
In order to solve problems in the prior art, the embodiment of the invention provides a kind of calculation methods of coal sample permeability.Institute
It is as follows to state technical solution:
The embodiment of the present invention provides a kind of calculation method of coal sample permeability, which comprises
Coal sample is pre-processed；
To carried out the pretreated coal sample carry out first time CT (Chinese: electronic computer tomography, English:
Computed Tomography) scanning, obtain first time scanning result；
Coal sample original permeability is calculated according to the first time scanning result；
Phase transformation processing is carried out to the coal sample；
To phase transformation, treated that the coal sample carries out second of CT scan, obtains second of scanning result；
According to second of scanning result, to coal sample, in a disguised form rear permeability is calculated；
To the coal sample original permeability being calculated and the coal sample, in a disguised form rear permeability is compared, and is permeated
Rate changes multiple.
Preferably, it is described to coal sample carry out pretreatment include:
Clean the coal sample surface；
It weighs to the coal sample；
The coal sample after weighing is immersed in distilled water, the moisture of the distilled water is fully absorbed；
It weighs again to the coal sample after the distilled water moisture is fully absorbed；
The water saturation of the coal sample is calculated according to the result that the coal sample is weighed.
Preferably, it is described using the first time scanning result to coal sample original permeability carry out calculate include:
Analytical calculation is carried out to the first time scanning result by three-dimensional imaging software, obtains original coal sample porosity；
According to the obtained water saturation and the original coal sample porosity, using formula 1 to the initial coal sample
Permeability is calculated:
Wherein, KiFor coal sample original permeability, SwtFor water saturation, φiFor coal sample primary porosity, C, x, y are normal
Number.
Preferably, according to second of scanning result to coal sample in a disguised form after permeability carry out calculate include:
Analytical calculation is carried out to second of scanning result by the three-dimensional imaging software, obtains coal sample hole after phase transformation
Porosity；
According to coal sample porosity after the obtained phase transformation, the covert rear coal sample permeability is counted using formula 2
It calculates:
Wherein, K is permeability after coal sample phase transformation, KiFor coal sample original permeability, φiFor coal sample primary porosity, φ is coal
Porosity after sample phase transformation.
Preferably, described to include: to coal sample progress phase transformation processing
The coal sample is put into closed container, places preset time after injecting enough liquid nitrogen；
Cooling operation is carried out to the closed container locating for the coal sample, so that the fluid in the coal sample condenses into admittedly
Body；
Restore the closed container to room temperature.
Preferably, the preset time is 12 hours.
Preferably, the method also includes:
Coal cinder to be measured is cut, the coal sample of a hexahedral shape is obtained.
Technical solution provided in an embodiment of the present invention has the benefit that
Then the calculation method of coal sample permeability provided in an embodiment of the present invention is passed through by carrying out CT scan to coal sample
Three-dimensional imaging software carries out analytical calculation to the result of CT scan, to calculate coal sample permeability, can not have in test coal
It is limited during sample permeability by the permeability of coal sample, the coal sample of permeability arbitrary size can be measured, and measuring
Phase change operation is carried out to these coal samples after the permeability of these coal samples, so that the permeability after these coal sample phase change operations is obtained,
Necessary preparation is done for later research and exploitation work.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment
Attached drawing is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, for
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is the calculation method flow chart for the coal sample permeability that the embodiment of the present invention one provides；
Fig. 2 is the calculation method flow chart of coal sample permeability provided by Embodiment 2 of the present invention.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art
Every other embodiment obtained without creative efforts, shall fall within the protection scope of the present invention.
Unless otherwise defined, the technical term or scientific term used herein should be in fields of the present invention and has
The ordinary meaning that the personage of general technical ability is understood.Used in present patent application specification and claims " the
One ", " second " and similar word are not offered as any sequence, quantity or importance, and are used only to distinguish different
Component part.Equally, the similar word such as "one" or " one " does not indicate that quantity limits yet, but indicates that there are at least one.
" connection " either the similar word such as " connected " is not limited to physics or mechanical connection, but may include electrical
Connection, it is either direct or indirect."upper", "lower", "left", "right" etc. are only used for indicating relative positional relationship, work as quilt
After the absolute position of description object changes, then the relative positional relationship also correspondingly changes.
Embodiment one
Referring to Fig. 1, the present embodiment includes: by the calculation method of coal sample permeability a kind of, the process of this method
Step 100 pre-processes coal sample.
Step 101 carries out first time CT scan to having carried out pretreated coal sample, obtains first time scanning result.
Step 102 calculates coal sample original permeability according to first time scanning result.
Step 103 carries out phase transformation processing to coal sample.
Step 104 carries out second of CT scan to phase transformation treated coal sample, obtains second of scanning result.
Step 105, according to second of scanning result, to coal sample, in a disguised form rear permeability is calculated.
Step 106, to the coal sample original permeability and coal sample being calculated, in a disguised form rear permeability is compared, and is permeated
Rate changes multiple.
Then the calculation method of coal sample permeability provided in an embodiment of the present invention is passed through by carrying out CT scan to coal sample
Three-dimensional imaging software carries out analytical calculation to the result of CT scan, to calculate coal sample permeability, can not have in test coal
It is limited during sample permeability by the permeability of coal sample, the coal sample of permeability arbitrary size can be measured, and measuring
Phase change operation is carried out to these coal samples after the permeability of these coal samples, so that the permeability after these coal sample phase change operations is obtained,
Necessary preparation is done for later research and exploitation work.
Embodiment two
Referring to fig. 2, the present embodiment provides a kind of calculation method of coal sample permeability, the process of this method includes:
Step 200 cuts coal cinder to be measured using cutting equipment, obtains the coal sample of a hexahedral shape.
Wherein, coal sample is generally cut into cuboid or square shape.
Optionally, coal sample can be cut into size are as follows: high 15 centimetres of the cuboid of wide 25 cm x of 30 cm x.
Cutting equipment used in this step can be it is existing arbitrarily can be to the instrument that coal cinder is cut, here not
It repeats one by one again.
It, will if carrying out multiple tracks cutting action to coal sample before test due to the crisp characteristic of coal cinder by operating above
Coal cinder is cut into circle, then coal sample chipping may cause test that can not continue during the test, and at this
In embodiment, the coal sample of hexahedral shape is obtained by simple cutting action, without cutting coal sample by multiple tracks cutting action
Be cut into circle, as far as possible guarantee coal sample in testing will not fragmentation, guarantee test go on smoothly.
Step 201 pre-processes coal sample in closed container.
Specifically, step 201 is specifically executed by step 2010- step 2014:
Step 2010, cleaning coal sample surface.
Step 2011 weighs to coal sample.
Step 2012 immerses the coal sample after weighing in distilled water, fully absorbs the moisture of distilled water.
Step 2013 is weighed again to fully absorbing the coal sample after distilled water moisture.
Step 2014, the water saturation that coal sample is calculated according to the result of coal sample weighing.
Step 202 is swept by German RayScan industrial CT system to pretreated coal sample progress first time CT has been carried out
It retouches, obtains first time scanning result.
Also other existing CT scan systems can be used in this step, first time CT scan are carried out to pretreated coal sample,
Here it no longer repeats one by one.
Step 203 calculates coal sample original permeability according to first time scanning result.
Specifically, step 203 is specifically executed by step 2030- step 2031:
Step 2030 carries out analytical calculation to first time scanning result by three-dimensional imaging software, obtains original coal sample hole
Porosity.
Wherein, three-dimensional imaging software uses the VG StudioMax2.2 software of Volume Graphics company of Germany.The
After single pass result is analyzed by three-dimensional imaging software, the numerical value of original coal sample porosity will be immediately arrived at.
The water saturation and original coal sample porosity that step 2031, basis obtain permeate initial coal sample using formula 1
Rate is calculated:
Wherein, KiFor coal sample original permeability, SwtFor water saturation, φiFor coal sample primary porosity, C, x, y are normal
Number.
Wherein, coal sample measured in the present embodiment has had phase by existing well-log information and testing injection/pressure fall
Close permeability data, therefore by survey permeability data to the constant carried out it is counter push away, to obtain the numerical value of C.
Such as: by the testing injection/pressure fall to certain coal bed gas block 10 well time, measuring its mean permeability is 0.0294
Microdarcy (english abbreviation: mD), further through the well log interpretation data of corresponding well, calculating mean permeability is 0.02mD, therefore
Calculating constant C is 0.7.
Wherein, x and y is the sequence of coal seam deposition.Stratum on one point spot deposition when, be divided into sequence, sequence is exactly
Refer to that the sequence of deposition, Different Strata have different sedimentary sequences, different regions needs geological scientific research personnel to carry out layering definition.
As soon as x and y are a constants, but different zones are different constant.
Wherein it is possible to initial coal sample permeability be calculated by computer or manually.
Step 204, in closed container, to coal sample carry out phase transformation processing.
Specifically, step 204 is specifically executed by step 2040- step 2042:
Coal sample is put into closed container by step 2040, places preset time after injecting enough liquid nitrogen.
Wherein, preset time is 12 hours.
Step 2041 carries out cooling operation to closed container locating for coal sample, so that the fluid in coal sample condenses into solid.
Wherein, in order to so that the temperature of closed container is quickly reduced to from room temperature so that the fluid in coal sample condense into it is solid
The temperature of body, so generally carrying out the fast cooling of coal sample by the way of taking closed container liquid nitrogen frozen.
Step 2042 restores closed container to room temperature.
Step 205, by Germany RayScan industrial CT system to phase transformation treated coal sample second of CT scan of progress,
Obtain second of scanning result.
Step 206, according to second of scanning result, to coal sample, in a disguised form rear permeability is calculated.
Specifically, step 206 is specifically executed by step 2060- step 2061:
Step 2060 carries out analytical calculation to second of scanning result by three-dimensional imaging software, obtains coal sample after phase transformation
Porosity.
Coal sample porosity after the phase transformation that step 2061, basis obtain counts covert rear coal sample permeability using formula 2
It calculates:
Wherein, K is permeability after coal sample phase transformation, KiFor coal sample original permeability, φiFor coal sample primary porosity, φ is coal
Porosity after sample phase transformation.
Wherein it is possible to pass through computer or covert rear coal sample permeability is manually calculated.
Step 207, to the coal sample original permeability and coal sample being calculated, in a disguised form rear permeability is compared, and is permeated
Rate changes multiple.
For example, the conclusion of obtained permeability variation multiple is as shown in table 1:
| Number | Former permeability/mD | Phase transformation permeability/mD | Increase multiple | Remarks |
| 1 | 0.57 | 4.94 | 8.7 | |
| 2 | 4.17 | 13.95 | 3.35 | There is obvious wide seam |
Table 1
Then the calculation method of coal sample permeability provided in an embodiment of the present invention is passed through by carrying out CT scan to coal sample
Three-dimensional imaging software carries out analytical calculation to the result of CT scan, to calculate coal sample permeability, can not have in test coal
It is limited during sample permeability by the permeability of coal sample, the coal sample of permeability arbitrary size can be measured, and measuring
Phase change operation is carried out to these coal samples after the permeability of these coal samples, so that the permeability after these coal sample phase change operations is obtained,
Necessary preparation is done for later research and exploitation work.
The serial number of the above embodiments of the invention is only for description, does not represent the advantages or disadvantages of the embodiments.
Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention., rather than its limitations；To the greatest extent
Pipe present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: its according to
So be possible to modify the technical solutions described in the foregoing embodiments, or to some or all of the technical features into
Row equivalent replacement；And these are modified or replaceed, various embodiments of the present invention technology that it does not separate the essence of the corresponding technical solution
The range of scheme.
Claims (6)
1. a kind of calculation method of coal sample permeability, which is characterized in that the described method includes:
Coal sample is pre-processed；
First time CT scan is carried out to the pretreated coal sample has been carried out, obtains first time scanning result；
Coal sample original permeability is calculated according to the first time scanning result；
Phase transformation processing is carried out to the coal sample；
To phase transformation, treated that the coal sample carries out second of CT scan, obtains second of scanning result；
According to second of scanning result, to coal sample, in a disguised form rear permeability is calculated；
To the coal sample original permeability being calculated and the coal sample, in a disguised form rear permeability is compared, and obtains permeability change
Change multiple；
It is described according to the first time scanning result to coal sample original permeability carry out calculate include:
Analytical calculation is carried out to the first time scanning result by three-dimensional imaging software, obtains original coal sample porosity；
According to obtained water saturation and the original coal sample porosity, using formula 1 to the initial coal sample permeability into
Row calculates:
Wherein, KiFor coal sample original permeability, SwtFor water saturation, φiFor coal sample primary porosity, C, x, y are constant.
2. the calculation method of coal sample permeability according to claim 1, which is characterized in that described to be pre-processed to coal sample
Include:
Clean coal sample surface；
It weighs to the coal sample；
The coal sample after weighing is immersed in distilled water, the moisture of the distilled water is fully absorbed；
It weighs again to the coal sample after the distilled water moisture is fully absorbed；
The water saturation of the coal sample is calculated according to the result that the coal sample is weighed.
3. the calculation method of coal sample permeability according to claim 1, which is characterized in that tied according to second of the scanning
Fruit to coal sample in a disguised form after permeability carry out calculate include:
Analytical calculation is carried out to second of scanning result by the three-dimensional imaging software, obtains coal sample hole after phase transformation
Degree；
According to coal sample porosity after the obtained phase transformation, the covert rear coal sample permeability is calculated using formula 2:
Wherein, K is permeability after coal sample phase transformation, KiFor coal sample original permeability, φiFor coal sample primary porosity, φ is coal sample phase
Porosity after change.
4. the calculation method of coal sample permeability according to claim 1, which is characterized in that described to carry out phase to the coal sample
Change is handled
The coal sample is put into closed container, places preset time after injecting enough liquid nitrogen；
Cooling operation is carried out to the closed container locating for the coal sample, so that the fluid in the coal sample condenses into solid；
Restore the closed container to room temperature.
5. the calculation method of coal sample permeability according to claim 4, which is characterized in that the preset time is 12 small
When.
6. the calculation method of coal sample permeability according to claim 1, which is characterized in that the method also includes:
Coal cinder to be measured is cut, the coal sample of a hexahedral shape is obtained.
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| CN112485174B (en) * | 2020-10-19 | 2021-09-14 | 中国地质大学（北京） | Method for calculating permeability of reservoir containing hydrate based on stacked cube model |
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| US8068579B1 (en) * | 2008-04-09 | 2011-11-29 | Xradia, Inc. | Process for examining mineral samples with X-ray microscope and projection systems |
| CN103743633A (en) * | 2014-01-24 | 2014-04-23 | 重庆大学 | Fluid structure interaction coal rock shear-seepage test device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8068579B1 (en) * | 2008-04-09 | 2011-11-29 | Xradia, Inc. | Process for examining mineral samples with X-ray microscope and projection systems |
| CN103743633A (en) * | 2014-01-24 | 2014-04-23 | 重庆大学 | Fluid structure interaction coal rock shear-seepage test device |
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| Title |
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| 基于CT扫描测定低渗岩心相对渗透率曲线的方法;冷振鹏等;《特种油气藏》;20130228;第20卷(第1期);第118页左栏第1段至第121页右栏第1段 |
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