CN107065033B - A kind of recognition methods of tight sandstone reservoir microcrack development and device - Google Patents
A kind of recognition methods of tight sandstone reservoir microcrack development and device Download PDFInfo
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Abstract
The present invention provides a kind of recognition methods of tight sandstone reservoir microcrack development and devices.The recognition methods include: obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；Calculate separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；Scatter plot is constructed according to the logarithm of the capillary pressure and the logarithm into mercury saturation degree；Linear fit is carried out to the target data point in the scatter plot, to obtain target fitting a straight line；According to the slope of the target fitting a straight line, identify whether purpose stratum microcrack develops.Technical solution provided by the invention is simple and convenient, and carry out quantitative judge whether can be developed to microcrack.
Description
Technical field
The present invention relates to a kind of recognition methods of tight sandstone reservoir microcrack development and devices, belong to geoanalytical techniques
Field.
Background technique
How the research hotspot that quantitative assessment is always this field is carried out to tight sand microcrack, this is to subsequent reservoir
It explores and develops and is most important.
By taking Ordos Basin in Palaeozoic as an example, with natural gas resource abundant.Third time resource assessment result table
Bright, there are 1.5 trillion side's natural gas resources in the basin south Paleozoic group, and exploration prospect is very huge.Gansu Province Dong Youqu Wei Yu E Erduo
This basin west and south, across Qingyang, two city of Pingliang, area is about 5 × 104km2, the 25% of basin our department area is accounted for, is long celebrating stone
The main battlefield of exploration activity exploitation.Since Gansu Province east area construction is complicated, natural gas exploration early period achievement is undesirable, current brill
Visit as the result is shown this area's gassiness series of strata it is relatively single, effective gas-bearing sandstone thinner thickness and distribution it is unstable, for meet exploration
Work is badly in need of studying a kind of method for capableing of quantitative assessment tight sand microcrack.
Currently used for evaluate microcrack method mainly include the following types:
1) crack is identified using imaging logging: mainly fine and close natural gas reservoirs is known using FMI imaging logging techniques
It not and evaluates, but this method can only provide conclusion since resolution ratio etc. limits from macroscopic perspective, effectively cannot identify and evaluate
The crack developed in tight sandstone reservoir.For example, using the full hole micro resistance imager (FMI) of Schlumberger to E Er
When Long1Jing, the Long2Jing and celebrating 3 wells of spy on more 1 section of this basin mountain are studied, it is found that it can only intuitively add macroscopical crack
With identification, and it is difficult to effectively identify microcrack (micron to the other crack of grade).
2) crack is identified using scanning electron microscope: the mainly rock pore using instruments such as SEM, FIB-SEM to micro-nano-scale
Gap is characterized, and this method is primarily present following drawback: 1. laboratory apparatus cost is high, and requires height to the production of sample, from
And it is also relatively high to result in experimental expenses；2. the sample due to scanning electron microscope is small-sized, although the dissection to partial structurtes
More fine, especially within the scope of nanoscale, but rest on morphology describes level, quantitative assessment hole knot to the technology more
The ability of structure is limited；3. to the primary identification with secondary fracture there is also certain limitation, especially because sample very little,
Influence of some induced fractures generated during sample preparation to result is very big.
3) reservoir is evaluated using high-pressure mercury experiment: conventional high-pressure mercury experiment can only obtain it is a series of about
Duty pressure (MPa), pore throat half in the parameter of pore throat character, such as replacement pressure (MPa), maximum pore throat radius (μm), saturation degree
Diameter intermediate value (μm), pore throat radius average value (μm), uniformity coefficient, lithology factor, maximum mercury saturation degree (%), efficiency of mercury withdrawal
(%), structural coefficient, feature structure coefficient, skewness (also known as flexure, kurtosis, coefficient of variation etc..But these parameters can not
Information about Reservoir Fracture is directly provided.
Therefore it provides a kind of recognition methods of tight sandstone reservoir microcrack development, whether microcrack can be developed into
Row quantitative judge becomes this field technical problem urgently to be resolved.
Summary of the invention
In order to solve the above technical problems, the purpose of the present invention is to provide a kind of identification sides of tight sand microcrack development
Method and device.Whether technical solution provided by the invention fast and effeciently the microcrack of tight sandstone reservoir can develop and known
Not, and quantitative data is provided.
In order to achieve the above objectives, the present invention provides a kind of recognition methods of tight sand microcrack development, this method packets
It includes:
Obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Calculate separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Logarithm and the logarithm into mercury saturation degree based on the capillary pressure construct scatter plot；
Linear fit is carried out to the target data point in the scatter plot, to obtain target fitting a straight line；
According to the slope of the target fitting a straight line, identify whether purpose stratum microcrack develops.
In the technical solution provided by the present invention, the logarithm of the capillary pressure and described into mercury saturation degree is calculated separately
Logarithm when, the functional form of logarithm may include Log, Ln, Log2Or Log10, without being limited thereto.
In the above-mentioned methods, it is preferable that according to the logarithm of the capillary pressure and the logarithm structure into mercury saturation degree
Build scatter plot include: using the logarithm of the capillary pressure as abscissa, using the logarithm into mercury saturation degree as ordinate, structure
Build scatter plot.
In the above-mentioned methods, it is preferable that this method further include: the distribution of data point in the scatter plot is analyzed,
To obtain the regularity of distribution of data point in the scatter plot；Wherein, the regularity of distribution of data point is as follows in the scatter plot: described
The distribution of data point is in the trend of one section or two sections or more different straight lines in scatter plot；When the trend in two sections or more different straight lines
When, the slope of every section of straight line is different.
In the above-mentioned methods, it is preferable that the number of targets strong point is chosen by following operation: in the scatter plot
Data point is grouped, and will be divided into one group in the data point of same section of trends of straight line distribution；On the basis of coordinate origin, from draw
That group data point near coordinate origin is chosen in the group divided as number of targets strong point.When being grouped to data point,
It is possible that following situations: being for example sequentially distributed 20 data points on scatter plot, the distribution of preceding 6 points (first group) is
It is obviously in a higher straight line of slope, the distribution trend of rear 13 points (second group) is then obviously more gentle in another slope
Straight line, wherein the 7th point is similar to be in the crossed position, be divided into first group can be formed together with preceding 6 points it is straight
Line, and straight line can also be formed together with rear 13 points by being divided into second group.In this case it can be performed such that 1. first
After 7th point is divided into first group, linear fit is carried out to two groups of data respectively, two fitting a straight lines is obtained and is denoted as L1 respectively
(first group of data) and L2 (second group of data)；2. the 7th data point is then divided into second group, similarly respectively to two groups
Data carry out linear fit, obtain L1 ' (first group of data) and L2 ' (second group of data)；3. finally by the L1 1. obtained and L2
Linear fit precision be compared respectively with the precision of the L1 ' and L2 ' linear fit that 2. obtain, choose precision it is higher that
Kind situation is grouped；In a practical situation, when there is above situation, the 7th point is assigned to first group or second group to final
Recognition result influence less, can almost ignore.
In the above-mentioned methods, it is preferable that according to the slope of the target fitting a straight line, identify purpose stratum microcrack
Whether development includes:
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
In the technical solution provided by the present invention, described " microcrack " is mainly one kind of fracture progress according to width
Classification, is primarily referred to as the crack of micron level.
In the technical solution provided by the present invention, described " high-pressure mercury experiment " be also referred to as " constant pressure press mercury experiment " or
" conventional pressure mercury experiment ", is one of the main method for measuring rock capillary pressure curve, can by high-pressure mercury experiment
To obtain the relation curve of mercury pressure and mercury saturation degree, also referred to as capillary pressure curve or intrusive mercury curve.The intrusive mercury curve
Including into mercury section and mercury ejection section, what it is into the reflection of mercury section is into during mercury, and pressure is gradually increasing, and mercury saturation degree is continuously increased；And
The reflection of mercury ejection section be mercury ejection during, pressure is gradually reduced, and mercury is gradually withdrawn from rock core, and mercury saturation degree constantly reduces.
In the technical solution provided by the present invention, described " under different capillary pressures into mercury saturation degree " can also be referred to as " different
Mercury saturation degree under into mercury pressure ", mainly reflects: into the mercury stage, mercury saturation degree under different capillary pressures is described
" under different capillary pressures into mercury saturation degree " are intrusive mercury curve into mercury segment data.
In pressure mercury experiment, with the continuous increase into mercury pressure, mercury constantly enters in smaller and smaller hole, due to
Mercury is non-wetted phase relative to rock, and contact angle is more constant, according to Washburn (1921) equation, a certain moment into
Mercury pressure (capillary pressure) value is corresponding with the aperture at the moment, therefore capillary pressure curve can provide corresponding hole ruler
Degree and distributed intelligence.
Technical solution provided by the invention has carried out deep exploratory development to whether tight sand microcrack develops, mainly
Research idea is as described below:
1) note mercury is carried out to rock sample under the conditions of different capillary pressures by high-pressure mercury experiment, to obtain different capillarys
Pipe pressure condition is corresponding into mercury saturation data；Then creatively capillary pressure curve and fractals principle are mutually tied
It closes, in the form of capillary (cylinder), Primary Construction is into the functional relation between mercury saturation degree and capillary pressure
Formula: SHg=aPc(D-2), in formula, SHg is into mercury saturation degree, and Pc is capillary pressure, and D is that hole divides shape, and a is coefficient；
2) logarithm is taken to the both sides of above-mentioned functional relation, obtain Log (SHg)=(D-2) × Log (aPc)=(D-2) ×
Log(aPc)+(D-2)×Log(a)；It can thus be seen that above-mentioned functional relation, both sides take after logarithm available one it is close
As straight line, the slope K of the straight line is D-2, i.e. D=K+2；
3) fractals principle is combined, determines the numberical range of point shape of hole are as follows: 2 < D < 3 obtain 0 < K < 1；Wherein, D
Value shows that the distribution of pore throat is more uniform, reservoir properties are better closer to 2；
4) it determines on the basis of coordinate origin, when first segment divides the slope K of shape≤1, microcrack agensis；First segment divides shape
Slope K 1 > 1 when, microcrack development.
In the above-mentioned methods, it is preferable that before carrying out high-pressure mercury experiment, this method is also wrapped to tight sandstone reservoir
Rock sample carries out pretreated step.For example contain oil gas in rock sample, then soxhlet type should be used to carry out oil suction to sample, then dried
It does to constant weight, pretreatment can reduce or eliminate the interference of foreign matter, the different capillary pressures for obtaining high-pressure mercury experiment
It is more accurate into mercury saturation data under power.
In the above-mentioned methods, it is preferable that high-pressure mercury experiment is carried out to the rock sample of tight sandstone reservoir, to obtain fine and close sand
The rock sample of rock reservoir under different capillary pressures includes: to set gradually different capillary pressures from small to large into mercury saturation degree
Power, and high-pressure mercury experiment is carried out to rock sample under different capillary pressures, it is corresponding into mercury to obtain different capillary pressures
Saturation degree.In the actual operation process, entire experimentation is carried out automatically in high-pressure mercury instrument, the setting of pressure
There are two types of mode, one is continuous pressurization, one is noncontinuity, staged pressurization (can be set the step-length of pressurization, and
Stay for some time at each pressure value, enable mercury well into all holes under the pressure), provided by the invention
In technical solution, noncontinuity, staged boost mode are selected, it is available different into the mercury saturation degree under mercury pressure, the mercury
Saturation degree is into mercury saturation degree.
In the above-mentioned methods, it is preferable that calculate separately the logarithm and pair into mercury saturation degree of the capillary pressure
Number includes: to be corrected to described into mercury saturation degree, with after being corrected into mercury saturation degree；Calculate separately the capillary pressure
The logarithm into mercury saturation degree after the logarithm of power and the correction.It is initial into the mercury stage when doing high-pressure mercury experiment
In, the increase into mercury quantity is due to non-wetted phase mercury falseness intrusive body caused by the fitting of the hole recess of rock sample rough surface
Product, with being gradually increased for pressure, hole is recessed to be taken by mercury, and mercury does not actually enter pore throat system also at this time, and pressure does not have yet
Reach replacement pressure, if this portion cavity volume be accumulated to total pore throat system into mercury quantity, will cause into mercury saturation degree
Numerical value is (this phenomenon is referred to as " hemp skin effect ") bigger than normal, can eliminate " hemp skin effect to being corrected into mercury saturation data
It answers ".
In a specific embodiment, this method comprises:
Rock sample in purpose stratum in acquisition tight sandstone reservoir；
Obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Calculate separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Using the logarithm of the capillary pressure as abscissa, using the logarithm into mercury saturation degree as ordinate, building dissipates
Point diagram；
The distribution of data point in the scatter plot is analyzed, to obtain the distribution rule of data point in the scatter plot
Rule；Wherein, the regularity of distribution of data point is as follows in the scatter plot: the distribution of data point is in one section or two sections in the scatter plot
The trend of the above difference straight line；When in the trend of two sections or more different straight lines, the slope of every section of straight line is different；
According to the regularity of distribution of data point in the scatter plot, data point therein is grouped, it will be straight in same section
The data point of line trend distribution is divided into one group；On the basis of coordinate origin, choose from the group of division near coordinate origin
That group data point as number of targets strong point；
Linear fit is carried out to the target data point in scatter plot, to obtain target fitting a straight line；
According to the slope of the target fitting a straight line, identify whether purpose stratum microcrack develops:
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
The present invention still further provides a kind of identification device of tight sand microcrack development, which includes:
Acquiring unit, for obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Computing unit, for calculating separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Construction unit, for constructing scatterplot according to the logarithm and the logarithm into mercury saturation degree of the capillary pressure
Figure；
Fitting unit is straight to obtain target fitting for carrying out linear fit to the target data point in the scatter plot
Line；
Recognition unit identifies whether purpose stratum microcrack is sent out for the slope according to the target fitting a straight line
It educates.
In above-mentioned apparatus, it is preferred that the device further includes high-pressure mercury instrument, for carrying out high-pressure mercury to the rock sample
Experiment.The highest experimental pressure of currently used high-pressure mercury instrument has experimental pressure up to 60000psi (about 414MPa)
Range is big, the fast feature of speed of experiment.
In above-mentioned apparatus, it is preferred that the construction unit be used for using the logarithm of the capillary pressure as abscissa, with
The logarithm into mercury saturation degree is ordinate, constructs scatter plot.
In above-mentioned apparatus, it is preferred that the device further includes analytical unit, for clicking through to the data in the scatter plot
Row analysis, to obtain the regularity of distribution of data point in the scatter plot；Wherein, the regularity of distribution of data point is such as in the scatter plot
Under:
The distribution of data point in the scatter plot is in the trend of one section or two sections or more different straight lines；When in two sections or more
When the trend of different straight lines, the slope of every section of straight line is different.
In above-mentioned apparatus, it is preferred that the device further includes selection unit, for choosing target data according to following operation
Point:
According to the regularity of distribution of data point in the scatter plot, data point therein is grouped, it will be straight in same section
The data point of line trend distribution is divided into one group；On the basis of coordinate origin, choose from the group of division near coordinate origin
That group data point as number of targets strong point.
In above-mentioned apparatus, it is preferred that the recognition unit is used for the slope according to the target fitting a straight line, identifies institute
State whether purpose stratum microcrack develops:
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
In above-mentioned apparatus, it is preferred that the computing unit further include:
Correct subelement, for being corrected to described into mercury saturation degree, with after being corrected into mercury saturation degree；
Computation subunit, for calculate separately the capillary pressure logarithm and the correction after into mercury be saturated
The logarithm of degree.
Beneficial effects of the present invention:
1) technical solution provided by the invention is simple and convenient, without the equipment that Electronic Speculum etc. is high, without complicated system
Sample process；
2) tight sandstone reservoir has the characteristics that low porosity and low permeability, porosity are usually less than 10%, and permeability is usually less than
1mD, existing technological means are difficult effectively to identify the microcrack wherein developed, and technical solution provided by the invention is by into mercury
Whether saturation degree and capillary pressure can develop carry out quantitative judge to microcrack, and effectively overcoming existing means can not be to cause
Whether the microcrack in close sandstone reservoir, which develops, is identified, even if although the electron microscopies such as SEM, FIB-SEM can carry out it is micro-
Metrical scale, nanoscale are portrayed, but the shortcomings that can only rest on topography level, can not carry out quantitative judge；
3) technical solution provided by the invention is creatively grouped the data point in scatter plot, will be straight in same section
The data point of line trend distribution is divided into one group；On the basis of coordinate origin, choose from the group of division near coordinate origin
That group data point as number of targets strong point, and to target data point carry out linear fit to obtain target fitting a straight line, will
For the slope of the target fitting a straight line of acquisition as direct quantitative criterion of identification existing for microcrack, recognition result is accurate and reliable.
Detailed description of the invention
Fig. 1 is the flow chart of recognition methods provided in an embodiment of the present invention；
Fig. 2 is the scatter plot of rock sample at 13 well 4111.84m of Gansu Province；
Fig. 3 is the scatter plot of rock sample at 6 well 4700.98m of Gansu Province；
Fig. 4 is the microscope following figure of rock core casting body flake at 6 well 4698.7m of Gansu Province；
Fig. 5 is the microscope following figure that rock core casting body flake at 2 well 3797.3m is visited in city；
Fig. 6 is the microscope following figure that rock sample inclusion enclave at 2 well 3809.73m is visited in city；
Fig. 7 is the microscope following figure that rock sample inclusion enclave at 2 well 3797.3m is visited in city；
Fig. 8 is the structural block diagram of identification device provided in an embodiment of the present invention.
Specific embodiment
In order to which technical characteristic of the invention, purpose and beneficial effect are more clearly understood, now to skill of the invention
Art scheme carries out described further below, but should not be understood as that limiting the scope of the invention.
The embodiment of the present invention is research with the southwestern Ordos Basin Gansu Province east Upper Paleozoic densification natural gas reservoirs
Object provides a kind of recognition methods of tight sandstone reservoir microcrack development, as shown in Figure 1, may comprise steps of:
Step S101: obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Obtain rock sample respectively out of different wells, it as shown in table 1, can be to rock in order to guarantee the accuracy of experimental data below
Sample is pre-processed, for example, if containing oil gas in rock sample, soxhlet type can be used and carry out oil suction to sample, be then dried to
Constant weight, pretreatment can eliminate disturbing factor, keep subsequent experimental data more accurate；
Carry out high-pressure mercury experiment (also referred to as constant pressure pressure mercury or conventional pressure mercury) respectively to above-mentioned rock sample: from small to large according to
The different capillary pressure (also referred to as into mercury pressure) of secondary setting, carries out note mercury to rock sample under different capillary pressures, with
Obtain under different capillary pressure Pc into mercury saturation degree SHg.
Table 1
Note: gas-bearing formation, poor gas-bearing formation develop microcrack, dried layer then microcrack agensis.
In the present embodiment, this field conventional means can be used into the metering of mercury saturation degree SHg, can located in advance in rock sample
It is by Gas Industry standard (SY/T) 5346- according to the People's Republic of China (PRC) before high-pressure mercury experiment starts after reason
2005 (Rock Capillary Pressure measurement), measure the gentle survey of gas permeability of above-mentioned rock sample respectively
Porosity can be determined by means of the two parameters into mercury saturation degree.
By taking rock sample at 13 well 4111.84m of Gansu Province as an example, after which carries out high-pressure mercury experiment, different capillarys can be obtained
Under pipe pressure Pc into mercury saturation degree SHg, being corrected into mercury saturation data to acquisition, as shown in table 2, in table 2
Into mercury saturation data be it is corrected after data.
Step S102: the logarithm and the logarithm into mercury saturation degree of the capillary pressure are calculated separately；
In the present embodiment, being corrected into mercury saturation data to acquisition, bearing calibration is referred to (SY/
T) the record in 5346-2005 (Rock Capillary Pressure measurement), with the dry of elimination " hemp skin effect "
It disturbs, keeps the data obtained more accurate.
Calculate separately the logarithm of capillary pressure Pc and the logarithm into mercury saturation degree SHg after correction；When calculating logarithm,
The functional form of logarithm can also be Ln, Log other than Log2、Log10Deng.
Step S103: scatter plot is constructed according to the logarithm of the capillary pressure and the logarithm into mercury saturation degree；
It is ordinate, Log (Pc) for abscissa with Log (SHg), constructs scatter plot.
By taking the scatter plot of rock sample at 13 well 4111.84m of Gansu Province as an example, the scatter plot from Fig. 2 as shown in Fig. 2, can be found that
The distribution of data point is very regular, it can be seen that trend in alignment between preceding 6 data points, and remaining data point
Then at the trend of another straight line, also, the slope significant difference of this two straight lines is very big.
In addition, the scatter plot is as shown in figure 3, can from Fig. 3 again by taking the scatter plot of rock sample at 6 well 4700.98m of Gansu Province as an example
To find the regularity of distribution in three-stage straight line of data point.
Step S104: linear fit is carried out to obtain target fitting a straight line to the target data point in the scatter plot；
According to the regularity of distribution of data point in scatter plot, data point therein is grouped, will be become in same section of straight line
The data point of gesture distribution is divided into one group；On the basis of coordinate origin, from the group of division choose near coordinate origin that
One group of data point is as number of targets strong point.The regularity of distribution of data point in scatter plot are as follows: the distribution of data point is usual in scatter plot
In the trend of one section or two sections or more different straight lines；When in the trend of two sections or more different straight lines, the slope of every section of straight line is
It is different.
Linear fit is carried out to target data point, to obtain target fitting a straight line.
By taking the scatter plot of rock sample at 13 well 4111.84m of Gansu Province as an example (as shown in Figure 2), 6 data points in front are obviously in figure
The distribution trend of straight line, and remaining data point is then in the distribution trend of another straight line, is carried out to the data point of front 6
The fitting of unitary once linear, obtains target fitting a straight line, which can be denoted as first segment straight line (L1), first segment
The slope K 1=2.629 of straight line, intercept a1=1.641；Remainder strong point can also carry out linear fit, obtained fitting a straight line
It can be denoted as second segment straight line (L2), the slope K 2=0.129 of second segment straight line, intercept a1=1.746.
Step S105: according to the slope of the target fitting a straight line, whether identifying purpose stratum microcrack develops；
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
By taking the rock sample of 13 Jing4111.84mChu of Gansu Province as an example, the slope K 1=2.629 for the first segment straight line (L1) being fitted,
Due to K1 > 1, determine that microcrack is developed at 13 well 4111.84m of Gansu Province.The recognition result of other wells is as shown in table 1.
Table 2
As can be seen from Table 1: 1) the data point aggregate performance of dried layer is the regularity of distribution of two-part straight line, and gas-bearing formation,
The data of poor gas-bearing formation may then show the regularity of distribution of three-stage straight line.2) slope K 1 of gas-bearing formation and poor gas-bearing formation first segment straight line
The significantly greater than slope K 1 of dried layer first segment straight line, and the slope K 1 of discovery gas-bearing formation and poor gas-bearing formation first segment straight line is almost without small
In 1 the case where；Wherein, the average value of the slope K 1 of gas-bearing formation first segment straight line is 2.45, the slope K 1 of poor gas-bearing formation first segment straight line
Average value be 4.5, and the slope K 1 of dry gas layer first segment straight line is most of less than 1, and another part is between 1-2.With
Dry gas layer is compared, and causes the slope K 1 of gas-bearing formation and poor gas-bearing formation as follows the reason of deviating considerably from 1: according to fractal principle, in nature
Substance there is the characteristic of " self similarity " to be referred to as a point shape, when " self similarity " property is higher, then fractal dimension is worth in a certain range
Lower, therefore, the K1 in gas-bearing formation and poor gas-bearing formation deviates considerably from 1, illustrates that its " self similarity " property is very low, due to being to be with capillary
Basic form carries out the derivation of equation, then the basis of " self similarity " should be by this model heap to the fractal theory come out
Capillary can speculate gas-bearing formation with the K1 value in poor gas-bearing formation significantly if K1 > 1 (i.e. D > 3), illustrate that it deviates from this model
It is to be occupied due to other in interstitial space " space type " leading, and this " space type " should be crack greater than 1.3)
Gas-bearing formation, poor gas-bearing formation develop microcrack, dried layer then microcrack agensis.
In addition, can be seen that the corresponding pore diameter range of six points on first segment straight line L1 at 1-4 μm in conjunction with table 2 and Fig. 2
Between change, therefore, the microcrack that can be characterized here is micro-meter scale.
For the reliability of recognition result in proof list 1, common casting body flake and fluid inclusion in comprehensive this field
Research method is visited 2 wells to above-mentioned Long6Jing and city and is studied.
By the rock core of 6 gas well gas layer (4698.7m) of Gansu Province be made casting body flake observed under the microscope (as shown in figure 4, from
Arrow head part in figure is, it is apparent that mineral grain develops obviously microcrack, target on its corresponding scatter plot
1) slope of fitting a straight line is significantly greater than, it is obvious that developing many microcracks in mineral grain；Likewise, city is visited 2
The rock core of well dried layer (3797.3m) be made casting body flake observed it is (bright in the particle of Fig. 5 as shown in figure 5, compared with Fig. 4
Microfissue agensis, the slope of target fitting a straight line is less than 1) on its corresponding scatter plot, it can clearly be seen that mineral grain
In microcrack and agensis, even if having part microcrack, but cementing in the later period.It can be seen that method provided by the invention obtains
To recognition result be reliable.
Inclusion enclave is made in the sample that 2 well difference gas-bearing formations (3809.73m) are visited in city to be observed under the microscope (such as Fig. 6 institute
Show), it is obvious that microcrack is developed, the fracture phenomena of mineral grain is apparent, and along some microcracks, finds gassiness
Inclusion enclave is distributed along microcrack, this controls natural gas accumulation to microcrack and provide strong evidence from hiding angle；
Likewise, inclusion enclave, which is made, in the sample that 2 well dried layer (3797.3m) are visited in city is observed (as shown in Figure 7), it can clearly be seen that
Mineral grain is more complete, and microcrack is less developed, and healing microcrack is only observed in Fig. 7.It can be seen that the present invention mentions
The recognition result that the technical solution of confession obtains is reliable.
Based on the same inventive concept, a kind of knowledge of tight sandstone reservoir microcrack development is additionally provided in the embodiment of the present invention
Other device, as described in the following examples.The principle solved the problems, such as due to the identification device of tight sandstone reservoir microcrack development
It is similar to the recognition methods of tight sandstone reservoir microcrack development, therefore the identification device of tight sandstone reservoir microcrack development
Implementation may refer to the implementation of the recognition methods of tight sandstone reservoir microcrack development, and overlaps will not be repeated.It is following to be made
, the combination of the software and/or hardware of predetermined function may be implemented in term " unit " or " module ".Although following embodiment
Described device preferably realized with software, but the combined realization of hardware or software and hardware be also may be simultaneously
It is contemplated.
Fig. 8 is a kind of structural block diagram of the identification device of the tight sandstone reservoir microcrack development of the embodiment of the present invention, should
Device includes: acquiring unit 801, computing unit 802, construction unit 803, fitting unit 804, recognition unit 805 below to this
Structure is illustrated.
Acquiring unit 801, for obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Computing unit 802, for calculating separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Construction unit 803, for constructing and dissipating according to the logarithm and the logarithm into mercury saturation degree of the capillary pressure
Point diagram；
Fitting unit 804, for carrying out linear fit to the target data point in the scatter plot to obtain target fitting
Straight line；
Whether recognition unit 805 identifies purpose stratum microcrack for the slope according to the target fitting a straight line
Development.
In one embodiment, the construction unit 803 specifically can be used for the logarithm of the capillary pressure for cross
Coordinate constructs scatter plot using the logarithm into mercury saturation degree as ordinate.
In one embodiment, the recognition unit 805 specifically can be used for the slope according to the target fitting a straight line,
Identify whether purpose stratum microcrack develops:
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
In one embodiment, the computing unit 802 can also include:
Correct subelement, for being corrected to described into mercury saturation degree, with after being corrected into mercury saturation degree；
Computation subunit, for calculate separately the capillary pressure logarithm and the correction after into mercury be saturated
The logarithm of degree.
In one embodiment, which can also include analytical unit, for clicking through to the data in the scatter plot
Row analysis, to obtain the regularity of distribution of data point in the scatter plot；Wherein, the regularity of distribution of data point is such as in the scatter plot
It is lower described:
The distribution of data point is in the trend of one section or two sections or more different straight lines in the scatter plot；
When in the trend of two sections or more different straight lines, the slope of every section of straight line is different.
In one embodiment, which can also include selection unit, for choosing target data according to following operation
Point:
Data point in the scatter plot is grouped, one will be divided into the data point of same section of trends of straight line distribution
Group；On the basis of coordinate origin, that group data point near coordinate origin is chosen from the group of division as target data
Point.
It can be seen from the above description that the embodiment of the present invention realizes following technical effect: obtaining in purpose stratum
Rock sample under different capillary pressures into mercury saturation degree；Calculate separately the capillary pressure logarithm and it is described into mercury be saturated
The logarithm of degree；Scatter plot is constructed according to the logarithm of the capillary pressure and the logarithm into mercury saturation degree；To the scatterplot
Target data point in figure carries out linear fit, to obtain target fitting a straight line；According to the slope of the target fitting a straight line, know
Whether the not described purpose stratum microcrack develops, and solves conventional technical means is difficult to whether develop tight sandstone reservoir crack
Whether the problem of effectively being identified develops for tight sandstone reservoir crack and provides the method for quantitative judge, be oil-gas reservoir at
Because the research of Dominated Factors provides strong basis.
Obviously, those skilled in the art should be understood that each module of the above-mentioned embodiment of the present invention or each step can be with
It is realized with general computing device, they can be concentrated on a single computing device, or be distributed in multiple computing devices
On composed network, optionally, they can be realized with the program code that computing device can perform, it is thus possible to by it
Store and be performed by computing device in the storage device, and in some cases, can be held with the sequence for being different from herein
The shown or described step of row, perhaps they are fabricated to each integrated circuit modules or will be multiple in them
Module or step are fabricated to single integrated circuit module to realize.In this way, the embodiment of the present invention be not limited to it is any specific hard
Part and software combine.
The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field
For art personnel, the embodiment of the present invention can have various modifications and variations.All within the spirits and principles of the present invention, made
Any modification, equivalent substitution, improvement and etc. should all be included in the protection scope of the present invention.
Claims (5)
1. a kind of recognition methods of tight sandstone reservoir microcrack development, this method comprises:
Obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Calculate separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Scatter plot is constructed according to the logarithm of the capillary pressure and the logarithm into mercury saturation degree, to number in the scatter plot
The distribution at strong point is analyzed, to obtain the regularity of distribution of data point in the scatter plot；
Include: according to the logarithm of the capillary pressure and the logarithm building scatter plot into mercury saturation degree
Using the logarithm of the capillary pressure as abscissa, using the logarithm into mercury saturation degree as ordinate, scatter plot is constructed；
Wherein, the regularity of distribution of data point is as follows in the scatter plot: the distribution of data point is in one section or two in the scatter plot
Section or more different straight lines trend；When in the trend of two sections or more different straight lines, the slope of every section of straight line is different；
Linear fit is carried out to the target data point in the scatter plot, to obtain target fitting a straight line；The number of targets strong point
It is to be chosen by following operation:
Data point in the scatter plot is grouped, one group will be divided into the data point of same section of trends of straight line distribution；
On the basis of coordinate origin, that group data point near coordinate origin is chosen from the group of division as number of targets strong point；
It according to the slope of the target fitting a straight line, identifies whether purpose stratum microcrack develops: when slope≤1, determining
The microcrack agensis of purpose stratum；
When slope > 1, determine that purpose stratum microcrack is developed.
2. the method according to claim 1, wherein the rock sample being saturated into mercury under different capillary pressures
Degree is to test to obtain by high-pressure mercury.
3. the method according to claim 1, wherein calculate separately the capillary pressure logarithm and it is described into
The logarithm of mercury saturation degree includes:
Be corrected to described into mercury saturation degree, with after being corrected into mercury saturation degree；
The logarithm and the logarithm into mercury saturation degree after the correction for calculating separately the capillary pressure.
4. a kind of identification device of tight sand microcrack development, the device include:
Acquiring unit, for obtain rock sample in purpose stratum under different capillary pressures into mercury saturation degree；
Computing unit, for calculating separately the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Construction unit, for constructing scatter plot according to the logarithm and the logarithm into mercury saturation degree of the capillary pressure；
Fitting unit, for carrying out linear fit to the target data point in the scatter plot, to obtain target fitting a straight line；
Recognition unit identifies whether purpose stratum microcrack develops for the slope according to the target fitting a straight line；
Analytical unit, for analyzing the data point in the scatter plot, to obtain point of data point in the scatter plot
Cloth rule；Wherein, the regularity of distribution of data point is as follows in the scatter plot:
The distribution of data point is in the trend of one section or two sections or more different straight lines in the scatter plot；
When in the trend of two sections or more different straight lines, the slope of every section of straight line is different；Selection unit, for according to such as
Number of targets strong point is chosen in lower operation:
Data point in the scatter plot is grouped, one group will be divided into the data point of same section of trends of straight line distribution；
On the basis of coordinate origin, that group data point near coordinate origin is chosen from the group of division as number of targets strong point；
The recognition unit is used for the slope according to the target fitting a straight line, identifies whether purpose stratum microcrack is sent out
It educates:
When slope≤1, the microcrack agensis of purpose stratum is determined；
When slope > 1, determine that purpose stratum microcrack is developed.
5. device according to claim 4, which is characterized in that the computing unit further include:
Correct subelement, for being corrected to described into mercury saturation degree, with after being corrected into mercury saturation degree；
Computation subunit, for calculate separately the capillary pressure logarithm and the correction after into mercury saturation degree
Logarithm.
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| CN110320569B (en) * | 2018-03-30 | 2021-07-27 | 中国石油化工股份有限公司 | Quantitative evaluation method for single well fracture development strength of compact sandstone reservoir |
| CN110567991B (en) * | 2018-10-29 | 2022-02-01 | 中国石油天然气股份有限公司 | Method and device for determining micro-crack development degree of tight sandstone reservoir |
| CN112682034B (en) * | 2020-12-04 | 2022-12-09 | 中国地质大学（北京） | Method and device for crack identification and dip angle characterization based on tight sandstone reservoir |
| CN113252711B (en) * | 2021-04-14 | 2023-12-22 | 成都理工大学 | Determination method of gas-liquid ratio of fluid inclusion and sub-minerals |
| CN113219553A (en) * | 2021-04-25 | 2021-08-06 | 中国石油大学(北京) | Method and device for predicting total organic carbon content of hydrocarbon source rock |
| CN115506758B (en) * | 2021-06-04 | 2024-05-28 | 中国石油天然气股份有限公司 | Method, device, equipment and storage medium for determining drainage and driving pressure of tight reservoir |
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