CN108802073A - A kind of rock electrical parameters acquisition methods and device based on digital cores - Google Patents
A kind of rock electrical parameters acquisition methods and device based on digital cores Download PDFInfo
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Abstract
Disclose a kind of rock electrical parameters acquisition methods and device based on digital cores.This approach includes the following steps：1) CT scan is carried out to rock core sample, obtains the gray level image of the rock core sample and builds 3-dimensional digital rock core；2) it is based on 3-dimensional digital rock core extraction rock core pore radius distribution；3) interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction；4) it is based on the distribution of rock core pore radius and interconnected porosity characterizes interstitial space fluid distrbution；5) tortuosity for calculating blowhole space, including saturation water flooding blowhole space tortuosity and oil-bearing rock interstitial space tortuosity are distributed based on interconnected pore space fluid；6) formation factor value when fully saturated water flooding is calculated；7) the resistance enhancement coefficient under different water cut saturation degree is calculated.The present invention can solve the problems, such as that the rock displacement for the rock core displacements such as tight sand difficulty is motionless and is difficult to obtain rock electrical parameters.
Description
Technical field
The present invention relates to the logging technique fields in petroleum exploration and development, and digital cores are based on more particularly, to one kind
Rock electrical parameters acquisition methods and device.
Background technology
Based on Archie formula, from rock simplify equivalent model (Yong Shihe, Zhang Chaomo log data processings with
The East China integrated interpretation [M]:Publishing house of University of Petroleum, 2007) it sets out, domestic and foreign scholars give identical rock electrical parameters
The quantitative calculation formula of correlation：
Wherein, F-lithostratigraphy factor；R0Resistivity when the fully saturated water flooding of-rock；Rw- stratum water resistance
Rate；LwThe length that-electric current passes through equivalent duct；L-rock sample length；φ-effecive porosity；τ-saturation water flooding rock pore
Gap space tortuosity；RI-resistance enhancement coefficient；Sw- water saturation；Rt- oil-bearing rock resistivity；L'w- oily sand
The equivalent volume length of rock conduction hole；τ '-oil-bearing rock interstitial space tortuosities.Domestic and foreign scholars are all based on greatly experiment pressure
The modes such as mercury data, well-log information obtain formation factor F and resistance enhancement coefficient RI.
Field currently is taken over as oil-gas exploration using tight sand as the unconventional reservoir of representative, but due to tight sand
Rock core is fine and close, and pore structure is poor, and rock core displacement difficulty causes existing technological means to be difficult to accurately obtain rock electrical parameters.With
The development of computer technology, the 3-dimensional digital of the reflection true interstitial space of rock can be rebuild according to rock's microstructure confidence
Rock core, the basic principle of digital cores is to be based on two-dimensional scan sem image or three-dimensional CT scan image, with computer picture
Treatment technology completes digital cores reconstruct by certain algorithm.3-dimensional digital rock core can carry out rock by means of numerical algorithm
Stone physical simulation experiment can make up many deficiencies of traditional means.Foreign scholar (Clennell M B.Tortuosity:a
guide through the maze[J].Geological Society of London Special Publications,
1997,122(1):299-344.Nakashima Y,Watanabe Y.Estimate of transport properties
of porous media by microfocus X-ray computed tomography and random walk
simulation[J].Water Resources Research,2002,38(38):8-1.Tobochnik J,Laing D,
Wilson G.Random-walk calculation of conductivity in continuum percolation.
[J].Physical Review A,1990,41(6):3052-3058.) on the basis of digital cores, using having method at random
Obtain the litho-electric parameters of rock.The amount on the one hand studied for tight sand is relatively fewer, on the other hand the precision of research
It cannot meet the requirements.
Inventor has found, existing rock electricity calculation formula only only considered tortuosity and electrical parameter influence, do not have
There is consideration pore throat radius.Tortuosity is identical, and the electrical response of pore throat radius difference rock is also different.Therefore, it is necessary to develop
A method of considering the factors such as tortuosity and hole duct radius and derives rock core rock electrical parameters.
The information for being disclosed in background of invention part is merely intended to deepen the reason of the general background technology to the present invention
Solution, and it is known to those skilled in the art existing to be not construed as recognizing or imply that the information is constituted in any form
Technology.
Invention content
Field currently is taken over as oil-gas exploration using tight sand as the unconventional reservoir of representative, but due to tight sand
Rock core is fine and close, and pore structure is poor, and rock core displacement difficulty obtains rock electrical parameters to traditional technological means and brings huge choose
War.The tortuosity that rock electrical parameters depend not only on interstitial space is also closely related with hole duct radius.Based on X ray CT
The 3-dimensional digital rock core of scanning provides a kind of new approaches obtaining rock electrical parameters, the shortcomings that existing method can be overcome and
It is insufficient.
According to an aspect of the invention, it is proposed that a kind of rock electrical parameters acquisition methods.This method may include following step
Suddenly：
1) CT scan is carried out to rock core sample, obtains the gray level image of the rock core sample and builds 3-dimensional digital rock core；
2) it is based on 3-dimensional digital rock core extraction rock core pore radius distribution；
3) interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction；
4) it is based on the distribution of rock core pore radius and interconnected porosity characterizes interstitial space fluid distrbution；
5) tortuosity for calculating blowhole space, including saturation water flooding rock are distributed based on interconnected pore space fluid
Interstitial space tortuosity and oil-bearing rock interstitial space tortuosity；
6) formation factor value when fully saturated water flooding is calculated；
7) the resistance enhancement coefficient under different water cut saturation degree is calculated.
It includes following sub-step to calculate the interconnected porosity of X-direction based on the 3-dimensional digital rock core in step 3)：
3.1) 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will scanned and this
The identical pixel of pixel is classified as a kind of until searching for until two boundaries of X-plane, the path shape of of a sort pixel composition
At a connected region, successively by each independent connected region line flag, setting flag symbol 1,2,3 ... n, n table in order
Show possessed connected region number in the data volume；
3.2) judge whether two boundary faces in 3-dimensional digital rock core X-direction have identical marker character, if there are phases
With marker character i, j ... m (1≤i, j ... m≤n), then this digital cores X-direction have connected region i, j ... m；
3.3) ratio of the sum of all hole pixels in connected region i, j ... m and 3-dimensional digital core data body size
The as interconnected porosity of X-direction,
Using interconnected porosity computational methods identical with X-direction calculating Y, the interconnected porosity of Z-direction.
Preferably, opening operation is done by the interconnected pore space to rock to characterize interconnected pore space fluid distribution.
Preferably, mean free path of the particle in different moments of Brownian movement is done in the space of interconnected pore by counting
To calculate the tortuosity in interconnected pore space.
Preferably, formation factor value F when saturation water flooding is calculated by following formula：
Wherein, RoIndicate resistivity when saturation water flooding, RwIndicate that formation water resistivity, τ indicate saturation water flooding rock
Interstitial space tortuosity, r indicate that average rock core pore radius, φ indicate interconnected porosity.
Preferably, the resistance enhancement coefficient under different water cut saturation degree is calculated by following formula：
Wherein, RtIndicate oil-bearing rock resistivity, RoIndicate that resistivity when saturation water flooding, τ ' indicate oil-bearing rock hole
Gap space tortuosity, τ indicate saturation water flooding blowhole space tortuosity, SwIndicate water saturation,φ is indicated
Interconnected porosity, φ ' indicate equivalent aqueous volume.
According to another aspect of the invention, it is proposed that a kind of rock electrical parameters acquisition device.The device includes memory, place
The computer program managed device and storage on a memory and can run on a processor, which is characterized in that the processor is held
Following steps are realized when row described program：
1) CT scan is carried out to rock core sample, obtains the gray level image of the rock core sample and builds 3-dimensional digital rock core；
2) it is based on 3-dimensional digital rock core extraction rock core pore radius distribution；
3) interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction；
4) it is based on the distribution of rock core pore radius and interconnected porosity characterizes interstitial space fluid distrbution；
5) tortuosity for calculating blowhole space, including saturation water flooding rock are distributed based on interconnected pore space fluid
Interstitial space tortuosity and oil-bearing rock interstitial space tortuosity；
6) formation factor value when fully saturated water flooding is calculated；
7) the resistance enhancement coefficient under different water cut saturation degree is calculated.
Preferably, it includes following sub-step to calculate the interconnected porosity of X-direction based on the 3-dimensional digital rock core in step 3)
Suddenly：
3.1) 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will scanned and this
The identical pixel of pixel is classified as a kind of until searching for until two boundaries of X-plane, the path shape of of a sort pixel composition
At a connected region, successively by each independent connected region line flag, setting flag symbol 1,2,3 ... n, n table in order
Show possessed connected region number in the data volume；
3.2) judge whether two boundary faces in 3-dimensional digital rock core X-direction have identical marker character, if there are phases
With marker character i, j ... m (1≤i, j ... m≤n), then this digital cores X-direction have connected region i, j ... m；
3.3) ratio of the sum of all hole pixels in connected region i, j ... m with 3-dimensional digital core data body size
The as interconnected porosity of X-direction,
Using interconnected porosity computational methods identical with X-direction calculating Y, the interconnected porosity of Z-direction.
Preferably, opening operation is done by the interconnected pore space to rock to characterize interconnected pore space fluid distribution.
Preferably, mean free path of the particle in different moments of Brownian movement is done in the space of interconnected pore by counting
To calculate the tortuosity in interconnected pore space.
The present invention is based on CT picture construction 3-dimensional digital core models carry out hole screen work analysis, based on mathematical morphology into
Row pore-fluid distribution characterization and random walk calculate rock tortuosity and then quantitatively export the electrical parameter of rock.With tradition
Ways and means are compared, Method And Principle of the invention be reliable, easy to understand, practical operability it is strong, it is often more important that can solve
Rock displacement certainly for the rock core displacements such as tight sand difficulty is motionless and is difficult to obtain the problem of rock electrical parameters, for research
The saturation exponent of such reservoir lays the foundation, and valence is applied with great in the tight sand exploration and development increasingly risen
Value.
Methods and apparatus of the present invention has other characteristics and advantages, these characteristics and advantages attached from what is be incorporated herein
It will be apparent in figure and subsequent specific embodiment, or will be in the attached drawing and subsequent specific implementation being incorporated herein
It is stated in detail in example, these the drawings and specific embodiments are used together to explain the specific principle of the present invention.
Description of the drawings
Exemplary embodiment of the present is described in more detail in conjunction with the accompanying drawings, of the invention is above-mentioned and other
Purpose, feature and advantage will be apparent, wherein in exemplary embodiments of the present invention, identical reference label is usual
Represent same parts.
Fig. 1 is the rock electrical parameters acquisition methods based on digital cores according to the exemplary implementation scheme of the present invention
Flow chart.
Fig. 2 is the schematic diagram of random walk model.
Fig. 3 is connectivity analysis schematic diagram.
Fig. 4 a are the schematic diagram that electric current flows through clean sandstone water layer；Fig. 4 b are the simplified model that electric current flows through clean sandstone water layer
Figure.
Fig. 5 a show tight sand rock core XX；Fig. 5 b are CT scan image；Fig. 5 c are the gray level image of binaryzation.
Fig. 6 is XX rock core pore network models.
Fig. 7 is XX rock cores duct radius distribution.
Fig. 8 a, Fig. 8 b, Fig. 8 c show XX rock cores in X, Y, the interconnected pore of Z-direction.
Fig. 9 a, Fig. 9 b, Fig. 9 c are XX rock cores in X, Y, the rock core interstitial space fluid distribution pattern of Z-direction.
Figure 10 is XX rock cores SwWith RI relation curves.
Specific implementation mode
The present invention is more fully described below with reference to accompanying drawings.Although showing the preferred embodiment of the present invention in attached drawing,
However, it is to be appreciated that may be realized in various forms the present invention without should be limited by embodiments set forth here.On the contrary, providing
These embodiments are of the invention more thorough and complete in order to make, and can will fully convey the scope of the invention to ability
The technical staff in domain.
Rock electrical parameters acquisition methods according to an exemplary embodiment of the present invention, master is described in detail below with reference to Fig. 1
Include the following steps：
Step 1：CT scan is carried out to rock core sample, the gray level image of the rock core sample is obtained and builds 3-dimensional digital rock
The heart.
Binary conversion treatment is carried out to CT scan image and obtains binary image, white represents rock matrix, and black represents rock
Stone hole；Picture construction 3-dimensional digital rock core based on CT scan simultaneously.
Step 2：Based on 3-dimensional digital rock core extraction rock core pore radius distribution.
The hole screen work of maximum ball drawing holes gap radius distribution can be utilized.
Step 3：Interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction.
The interconnected porosity of all directions can be calculated using cluster labeling algorithm, include the interconnected porosity of X, Y, Z-direction.
Pore radius is distributed as key parameter structural element radius in mathematical morphology characterization interstitial space fluid distrbution
It chooses and foundation is provided, while the calculating of interconnected porosity can do anisotropic analysis to electrical parameter.
Specifically, it includes following sub-step to calculate the interconnected porosity of X-direction based on the 3-dimensional digital rock core in step 3)
Suddenly：
3.1) 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will scanned and this
The identical pixel of pixel is classified as a kind of until searching for until two boundaries of X-plane, the path shape of of a sort pixel composition
At a connected region, successively by each independent connected region line flag, setting flag symbol 1,2,3 ... n, n table in order
Show possessed connected region number in the data volume；
3.2) judge whether two boundary faces in 3-dimensional digital rock core X-direction have identical marker character, if there are phases
With marker character i, j ... m (1≤i, j ... m≤n), then this digital cores X-direction have connected region i, j ... m；
3.3) ratio of the sum of all hole pixels in connected region i, j ... m and 3-dimensional digital core data body size
The as interconnected porosity of X-direction.
Using interconnected porosity computational methods identical with X-direction calculating Y, the interconnected porosity of Z-direction.
Specifically, for Y-direction, 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, it will
Scan to pixel identical with the pixel be classified as a kind of until searching for until two boundaries of Y plane, of a sort picture
The path of element composition forms a connected region, successively by each independent connected region line flag, setting flag in order
Symbol 1,2,3 ... n, n indicate possessed connected region number in the data volume；Judge two in 3-dimensional digital rock core Y-direction
Whether a boundary face has identical marker character, if there are identical marker character i, j ... m (1≤i, j ... m≤n), then this number
Rock core has connected region i, j ... m in X-direction；The sum of all hole pixels in connected region i, j ... m and 3-dimensional digital rock
The ratio of heart data volume size is the interconnected porosity of Y-direction.
For Z-direction, 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will be scanned
Pixel identical with the pixel be classified as it is a kind of until searching for until two boundaries of Z plane, of a sort pixel composition
Path forms a connected region, successively by each independent connected region line flag, setting flag symbol 1,2,3 ... in order
N, n indicate possessed connected region number in the data volume；Judging two boundary faces in 3-dimensional digital rock core Z-direction is
No to have identical marker character, if there are identical marker character i, j ... m (1≤i, j ... m≤n), then this digital cores is in X-direction
With connected region i, j ... m；The sum of all hole pixels in connected region i, j ... m and 3-dimensional digital core data body size
Ratio be Z-direction interconnected porosity.
As shown in figure 3, having to being marked after three-dimensional data swept-volume, 2,3,4 four independent connected domains, before X-direction
There is the pixel labeled as 3 in latter two face, then in the X direction, all pixels point in connected region that marker character is 3 is remembered
Record is got off, and the calculating of the interconnected porosity of X-direction is participated in；In the Y direction, all pixels in connected region that marker character is 2
Point is recorded, and participates in the calculating of the interconnected porosity of Y-direction；In z-direction, marker character is the institute in 1 connected region
There is pixel to be recorded, participates in the calculating of the interconnected porosity of Z-direction；The connected domain for being 4 for marker character, after being not involved in
Continuous simulation calculates.
Step 4：Interstitial space fluid distrbution is characterized based on the distribution of rock core pore radius and interconnected porosity.
Mathematical Morphology Method can be utilized to characterize interstitial space fluid distrbution.Specifically, the company to rock can be passed through
Logical interstitial space does opening operation to characterize interconnected pore space fluid distribution.Important parameter is structural element in opening operation algorithm
Radius, the result after opening operation is to remain larger than the space of structural element radius.The value for gradually changing structural element radius can
To characterize the fluid distrbution under different water cut saturation degree.
Step 5：The tortuosity for calculating blowhole space, including saturation water flooding are distributed based on interconnected pore space fluid
Blowhole space tortuosity and oil-bearing rock interstitial space tortuosity.
The simulation of random walk method can be utilized to calculate the tortuosity in interconnected pore space, you can be connected to by statistics
The particle that interstitial space does Brownian movement calculates the tortuosity in interconnected pore space in the mean free path of different moments, such as schemes
Shown in 2.
Specifically, since particle in interstitial space does Brownian movement, the average freedom of different moments particle is counted
Journey can be obtained by the tortuosity of interstitial space.Wherein saturation water flooding blowhole space tortuosity represent water saturation as
When 100%, oil-bearing rock interstitial space tortuosity then indicates water saturation<Blowhole space tortuosity when 100%.
Step 6：Calculate formation factor value when fully saturated water flooding.
The saturation that the interconnected porosity and step 5 that the pore radius distribution that is obtained based on step 2, step 3 are obtained obtain
Water flooding blowhole space tortuosity calculates formation factor value when saturation water flooding according to formula proposed by the present invention (3)：
Wherein, RoIndicate resistivity when saturation water flooding, RwIndicate that formation water resistivity, τ indicate saturation water flooding rock
Interstitial space tortuosity, r indicate that average rock core pore radius, φ indicate interconnected porosity.Average rock core pore radius can lead to
It crosses to count the distribution of rock core pore radius and be obtained.
The specific derivation process of formula (1) is as follows：
T/ τ are defined as parameter of pore structure S, and (the beginning of spring that rectifies utilizes discussion [J] of Logging Data To Evaluate reservoir properties
Logging technique, 1992,16 (2):117-119.), i.e.,
The S concentrated expressions size and tortuous in reservoir mesoporous lyriform pore road.If hole duct is bigger, more straight, S values
It is bigger, then illustrate that reservoir is better；, whereas if hole duct is more tiny, more tortuous, then S values are smaller, then reservoir becomes
Difference.
Assuming that rock matrix is non-conductive, electric current flows through the schematic diagram of clean sandstone water layer as shown in fig. 4 a, and simplified model is as schemed
Shown in 4b.In fig.4, AwIndicate that electric current flows through the sectional area in equivalent duct；LwIndicate that electric current flows through the length in equivalent duct, A
Indicate rock cross-sectional area, r0Indicate that the resistance of rock, other parameters meaning are same as above；In fig. 4b, rmaIndicate the resistance of skeleton,
rwIndicate the resistance of pore-fluid.
From the simplified model figure of rock：
The porosity of rock can be expressed as：
By formula (7) and (10), can be obtained in conjunction with (5) and (9)：
According to strange first formula of A Er：
Simultaneous formula (9) and (10) obtain：
Step 7：Calculate the resistance enhancement coefficient under different water cut saturation degree.
When blowhole part oil-containing i.e. two phase fluid are saturated, according to formula (3), when rock oil-containing equally
Layer factor F ' be：
Wherein, RtIndicate oil-bearing rock resistivity, RwIndicate that formation water resistivity, τ ' are rock oil-bearing rock interstitial space
Tortuosity, φ ' are equivalent aqueous volume；By formula (3) divided by (13), the then resistance enhancement coefficient under different water cut saturation degree
It can be rewritten as：
Wherein, τ indicates saturation water flooding blowhole space tortuosity,φ indicates interconnected porosity.
Using example
By taking tight sand rock core XX shown in Fig. 5 a as an example, core experiment helium porosity is 8.6%, air permeability
For 0.01md, scan size size is 300*300*300 voxels, and CT resolution ratio is 12um.CT scan, gained are carried out to rock core XX
The scan image arrived is as shown in Figure 5 b, is handled to obtain that binary image is as shown in Figure 5 c, and white represents rock to scan image
Stone skeleton, black represent blowhole.
On the basis of 3-dimensional digital rock core, pore network model, hole ball table can be built using biggest ball algorithm
Show, venturi is indicated with cylinder, and then the pore radius distribution for obtaining rock core is as shown in Figure 6, Figure 7, the largest hole of XX rock cores in figure
Gap radius is 100um, average pore radius 43um.
The interconnected porosity of all directions, the interconnected pore of the rock core X-direction can be calculated using cluster labeling algorithm simultaneously
Degree is 3.6%, as shown in Figure 8 a；The interconnected porosity of Y-direction is 5.19%, as shown in Figure 8 b；Z-direction (core test direction)
Interconnected porosity be 5.14%, as shown in Figure 8 c.
The tortuosity for calculating interconnected pore space can be simulated using random walk method.And then it utilizes proposed by the present invention
The formation factor F values that rock Z-direction is calculated in formula (1) are 134；The result that existing F values calculation formula (3) calculates is
248, the F values that laboratory measures are 88.Opening operation is done to interconnected pore space using maximum pore radius and can be obtained by hole
The fluid distrbution in space, the fluid distrbution of interstitial space is as shown in Fig. 9 a, Fig. 9 b, Fig. 9 c in X-direction, Y-direction, Z-direction.?
Interstitial space tortuosity is recalculated on the basis of this, resistance enhancement coefficient RI can be obtained using formula (4), changes opening operation half
The value of diameter can characterize different water cut saturation degree and then can obtain different RI, and as shown in Figure 10, orbicular spot represents real
It tests as a result, triangle represents formula (4) numerical simulation result, box represents formula (2) numerical simulation result.It can be seen that one
Aspect numerical simulation can accomplish lower water saturation than experiment, on the other hand within the scope of relatively high water saturation
The numerical simulation result feasibility for demonstrating the technological invention consistent with experimental result.The saturation exponent that formula (2) fits
Value range, while formula (4) precision higher compared with formula (2) obviously are had exceeded for 218, for further research tight sand
Resistance enhancement coefficient and saturation degree between relationship establish one basis, this also be exactly the purpose of the present invention and meaning.
It will be understood by those skilled in the art that above to the purpose of the description of the embodiment of the present invention only for illustratively saying
The advantageous effect of bright the embodiment of the present invention is not intended to limit embodiments of the invention to given any example.
Various embodiments of the present invention are described above, above description is exemplary, and non-exclusive, and
It is not limited to disclosed each embodiment.Without departing from the scope and spirit of illustrated each embodiment, for this skill
Many modifications and changes will be apparent from for the those of ordinary skill in art field.The selection of term used herein, purport
In the principle, practical application or improvement to the technology in market for best explaining each embodiment, or make the art
Other those of ordinary skill can understand each embodiment disclosed herein.
Claims (10)
1. a kind of rock electrical parameters acquisition methods based on digital cores, which is characterized in that the rock electrical parameters obtain
Method includes the following steps：
1) CT scan is carried out to rock core sample, obtains the gray level image of the rock core sample and builds 3-dimensional digital rock core；
2) it is based on 3-dimensional digital rock core extraction rock core pore radius distribution；
3) interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction；
4) it is based on the distribution of rock core pore radius and interconnected porosity characterizes interstitial space fluid distrbution；
5) tortuosity for calculating blowhole space, including saturation water flooding blowhole are distributed based on interconnected pore space fluid
Space tortuosity and oil-bearing rock interstitial space tortuosity；
6) formation factor value when fully saturated water flooding is calculated；
7) the resistance enhancement coefficient under different water cut saturation degree is calculated.
2. the rock electrical parameters acquisition methods according to claim 1 based on digital cores, which is characterized in that step 3)
In based on the 3-dimensional digital rock core calculate X-direction interconnected porosity include following sub-step：
3.1) 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will scanned and the pixel
Identical pixel is classified as a kind of until searching for until two boundaries of X-plane, the path formation one of of a sort pixel composition
A connected region, successively by each independent connected region line flag, n, n indicate institute to setting flag symbol 1,2,3 ... in order
State possessed connected region number in data volume；
3.2) judge whether two boundary faces in 3-dimensional digital rock core X-direction have identical marker character, if there are identical
Marker character i, j ... m (1≤i, j ... m≤n), then this digital cores X-direction have connected region i, j ... m；
3.3) the sum of all hole pixels in connected region i, j ... m and the ratio of 3-dimensional digital core data body size are X
The interconnected porosity in direction,
Using interconnected porosity computational methods identical with X-direction calculating Y, the interconnected porosity of Z-direction.
3. the rock electrical parameters acquisition methods according to claim 1 based on digital cores, which is characterized in that by right
Opening operation is done to characterize interconnected pore space fluid distribution in the interconnected pore space of rock.
4. the rock electrical parameters acquisition methods according to claim 1 based on digital cores, which is characterized in that pass through system
The particle that meter does Brownian movement in the space of interconnected pore calculates interconnected pore space in the mean free path of different moments
Tortuosity.
5. the rock electrical parameters acquisition methods according to claim 1 based on digital cores, which is characterized in that by such as
Lower formula calculates formation factor value F when saturation water flooding：
Wherein, RoIndicate resistivity when saturation water flooding, RwIndicate that formation water resistivity, τ indicate saturation water flooding blowhole
Space tortuosity, r indicate that average rock core pore radius, φ indicate interconnected porosity.
6. the rock electrical parameters acquisition methods according to claim 1 based on digital cores, which is characterized in that by such as
Lower formula calculates the resistance enhancement coefficient under different water cut saturation degree：
Wherein, RtIndicate oil-bearing rock resistivity, RoIndicate that resistivity when saturation water flooding, τ ' indicate that oil-bearing rock hole is empty
Between tortuosity, τ indicates saturation water flooding blowhole space tortuosity, SwIndicate water saturation,φ indicates connection
Porosity, φ ' indicate equivalent aqueous volume.
7. a kind of rock electrical parameters acquisition device based on digital cores, which is characterized in that described device includes memory, place
The computer program managed device and storage on a memory and can run on a processor, which is characterized in that the processor is held
Following steps are realized when row described program：
1) CT scan is carried out to rock core sample, obtains the gray level image of the rock core sample and builds 3-dimensional digital rock core；
2) it is based on 3-dimensional digital rock core extraction rock core pore radius distribution；
3) interconnected porosity based on 3-dimensional digital rock core calculating X, Y, Z-direction；
4) it is based on the distribution of rock core pore radius and interconnected porosity characterizes interstitial space fluid distrbution；
5) tortuosity for calculating blowhole space, including saturation water flooding blowhole are distributed based on interconnected pore space fluid
Space tortuosity and oil-bearing rock interstitial space tortuosity；
6) formation factor value when fully saturated water flooding is calculated；
7) the resistance enhancement coefficient under different water cut saturation degree is calculated.
8. the rock electrical parameters acquisition device according to claim 7 based on digital cores, which is characterized in that step 3)
In based on the 3-dimensional digital rock core calculate X-direction interconnected porosity include following sub-step：
3.1) 26 neighbor scans are carried out to each pixel in 3-dimensional digital core data body, will scanned and the pixel
Identical pixel is classified as a kind of until searching for until two boundaries of X-plane, the path formation one of of a sort pixel composition
A connected region, successively by each independent connected region line flag, n, n indicate institute to setting flag symbol 1,2,3 ... in order
State possessed connected region number in data volume；
3.2) judge whether two boundary faces in 3-dimensional digital rock core X-direction have identical marker character, if there are identical
Marker character i, j ... m (1≤i, j ... m≤n), then this digital cores X-direction have connected region i, j ... m；
3.3) the sum of all hole pixels in connected region i, j ... m and the ratio of 3-dimensional digital core data body size are X
The interconnected porosity in direction,
Using interconnected porosity computational methods identical with X-direction calculating Y, the interconnected porosity of Z-direction.
9. the rock electrical parameters acquisition device according to claim 7 based on digital cores, which is characterized in that by right
Opening operation is done to characterize interconnected pore space fluid distribution in the interconnected pore space of rock.
10. the rock electrical parameters acquisition device according to claim 7 based on digital cores, which is characterized in that pass through
The particle that statistics does Brownian movement in the space of interconnected pore calculates interconnected pore space in the mean free path of different moments
Tortuosity.
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