CN115876668A - Petroleum reservoir porosity measuring and calculating method based on core - Google Patents
Petroleum reservoir porosity measuring and calculating method based on core Download PDFInfo
- Publication number
- CN115876668A CN115876668A CN202310145517.9A CN202310145517A CN115876668A CN 115876668 A CN115876668 A CN 115876668A CN 202310145517 A CN202310145517 A CN 202310145517A CN 115876668 A CN115876668 A CN 115876668A
- Authority
- CN
- China
- Prior art keywords
- porosity
- area
- scanning
- core
- closed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000003208 petroleum Substances 0.000 title claims description 27
- 239000011435 rock Substances 0.000 claims abstract description 33
- 238000005266 casting Methods 0.000 claims abstract description 19
- 238000005553 drilling Methods 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 230000005484 gravity Effects 0.000 claims description 18
- 238000012937 correction Methods 0.000 claims description 14
- 238000012545 processing Methods 0.000 claims description 13
- 230000006870 function Effects 0.000 claims description 10
- 238000003860 storage Methods 0.000 claims description 10
- 238000004590 computer program Methods 0.000 claims description 8
- 239000003795 chemical substances by application Substances 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 7
- 239000003822 epoxy resin Substances 0.000 claims description 6
- 229920000647 polyepoxide Polymers 0.000 claims description 6
- 238000007598 dipping method Methods 0.000 claims description 4
- 238000003708 edge detection Methods 0.000 claims description 3
- 238000004458 analytical method Methods 0.000 abstract description 12
- 239000011148 porous material Substances 0.000 abstract description 8
- 238000004868 gas analysis Methods 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 23
- 238000004364 calculation method Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000009191 jumping Effects 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004043 dyeing Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000012757 fluorescence staining Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000005481 NMR spectroscopy Methods 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000003703 image analysis method Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000001225 nuclear magnetic resonance method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
Abstract
The invention discloses a method for measuring and calculating the porosity of an oil reservoir based on a rock core, which comprises the steps of drilling the rock core, manufacturing a casting body slice, scanning the casting body slice to obtain a scanning picture, calculating the porosity, and correcting the porosity according to a pore-gap relation to obtain the corrected porosity. The method has strong adaptability, realizes the acquisition of a high-resolution core scanning photo by laser confocal scanning, obtains more accurate porosity after correcting the scanning photo according to the geometric shape and size of a pore, provides more accurate information for oil-gas analysis, and solves the problem of analysis errors caused by more photo details when the core analysis is carried out by the laser confocal scanning.
Description
Technical Field
The invention relates to the technical field of geophysical exploration, in particular to a method for measuring and calculating the porosity of a petroleum reservoir based on a rock core.
Background
Porosity is an inherent property of reservoir rock and is also a fundamental parameter for hydrocarbon reservoir evaluation. The porosity is the percentage of the volume of the pores in the rock to the total volume of the rock, and represents that the porosity is an important physical parameter for controlling oil and gas reserves and energy storage, and the porosity is an important research object in the process of researching, evaluating and predicting reservoirs.
The existing method for measuring the porosity of the rock core comprises the steps of rock core observation, an image analysis method, a casting body slice method and a scanning electron microscope method; indirect determination: mercury intrusion capillary method, nuclear magnetic resonance measurement.
The helium method has the advantages of simplicity in operation, low cost, short time and the like, is the most common experimental measurement method for the effective porosity, but the pore structure of a compact reservoir is complex, and the obtained measurement result cannot reflect the condition of oil gas storage, for example, in the Chinese patent application with the publication number of CN108956422A, the effective porosity, the flow porosity and the diffusion porosity are obtained by using a three-time nitrogen method for testing and correcting data, but the data processing process is complex and is difficult to adapt to different rocks. The nuclear magnetic resonance method can accurately calculate the effective porosity of the compact oil reservoir, but has the advantages of long measurement period, expensive equipment, few characterization parameters and lack of objective and comprehensive evaluation on the application effect of various reservoirs. The mercury intrusion capillary method has accurate detection results but the use scene is limited by a laboratory.
The porosity is the percentage of the porosity volume in the total volume of the rock, and as no pore exists in the non-drilled coarse particle clastic particles, but the particles occupy the volume of the rock sample, the porosity measured by using a standard rock core column sample with the diameter of 25mm is larger than the actual porosity of the gravel sandstone reservoir, so that the risk of misjudgment on oil and gas exploration and development is possibly brought. The effective porosity is the ratio of the volume of interconnected pores in the rock to the total volume of the rock, and is an important parameter for evaluating oil and gas reservoirs.
According to the conventional porosity measurement method, a standard core column sample with the diameter of 25mm is drilled from a full-diameter core, and the porosity of the standard core column sample is measured by adopting the conventional porosity measurement method, but because the problem that coarse debris particles are broken and fall off exists in the core column sample of a compact reservoir, the selection of the core column sample is limited, and the measured data cannot effectively reflect the storage condition of oil gas.
The laser confocal scanning microscope is an optical microscopic testing method which is started in the 80 to 90 th ages of the 20 th century, and the high magnification and resolution can make up the limitation of using a common microscope to carry out structural observation in the pores of the traditional reservoir. The application of the laser confocal scanning technology can acquire more information from the rock core, can more accurately measure the porosity, the microporosity and the throat, has measurement precision obviously superior to that of a common microscope, and provides support for oil-gas exploration.
Disclosure of Invention
The invention aims to provide a method for measuring and calculating the porosity of an oil reservoir based on a core, which solves the problem of small measurement result caused by the breakage and falling of coarse debris particles in a core column sample in the prior art by correcting a core casting body slice photo of a compact reservoir and at least provides a beneficial selection or creation condition.
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
a core-based petroleum reservoir porosity estimation method, the method comprising the steps of:
step 1, drilling a rock core and manufacturing a casting body slice;
step 2, scanning the casting body slice to obtain a scanning picture, and calculating the porosity;
step 3, correcting the porosity according to the pore-gap relation;
and 4, obtaining the corrected porosity.
Further, in step 1, the substep of drilling the core and manufacturing the casting body slice is as follows:
drilling a standard core pillar sample with the diameter of 25mm, injecting an epoxy resin impregnating agent into the standard core pillar sample, and grinding a prepared rock slice (generally 0.1 mm to 5 mm) after the epoxy resin impregnating agent is cured.
Further, in step 2, scanning the casting sheet to obtain a scanning photograph, and the sub-step of calculating the porosity is:
scanning the cast body slice of the rock core by using a laser confocal microscope to obtain a scanning sheet; carrying out graying treatment on the scanning film;
obtaining an edge curve through an edge detection operator, dividing a scanning sheet into a plurality of closed regions by the edge curve, setting a threshold value of the area of each closed region as a gap size threshold value THRS, and forming a first region set by the region of each closed region, the area of which is larger than the gap size threshold value;
recording the total area of all closed areas in the first area set as a first area S1, enabling the area S0 of the core to be the view area of the current scanning sheet, and calculating the porosity phi = S1/S0; if S1 is larger than 0, the closed area with the largest area in the first area set is MAXR, and the geometric gravity center point of the MAXR is MAXR 0 。
Preferably, the gap size threshold THRS may be set empirically or based on historical data.
Further, in step 3, the sub-step of correcting the porosity according to the pore-gap relationship is as follows:
the closed regions in the MSet are sorted in a descending order according to the size by taking the formed slot set MSet of the closed regions which do not belong to the first region set in each closed region of the scanning film, MSeti is taken as the ith closed region in the set, and i is a positive integer; initializing a variable i to be 2, setting the size of a slot set MSet to be N, and setting i to be in an element of [1, N ]; setting a variable as a correction ratio CD;
step 3.1, taking the geometric gravity center point of the closed area with the largest area in the scanning sheet as a reference point PA, and increasing the value of i by 1;
and 3.2, carrying out corner point detection on the closed region MSeti, and skipping to the step 3.2.1 if the number of corner points is less than 3, otherwise skipping to the step 3.2.2.
The obtained scanning sheet can be divided into a plurality of areas, the size and the geometric shape of the areas can influence reservoir analysis, the further classification of the divided areas is helpful for enabling the correction process to be more accurate, and whether the oil gas in the gap tends to be extracted or not is judged according to the distance from the gap to the maximum closed area.
Step 3.2.1, performing circle recognition (namely Hough circle detection) on the closed area MSeti to detect a circle, wherein the detected circle is surrounded by the closed area and has the maximum radius (because in a core of an oil and gas reservoir, a circular cavity is frequently formed on a core slice caused by oil and gas erosion or natural storage of oil and gas (bubbles or the oil and gas in the core are generally circular), and the oil and gas extrusion gap in the circular cavity causes the gap to shift on an image, so that the gap position needs to be corrected); the circle center of the circle is C, the radius of the circle is R, the geometric gravity center point of the current closed area is recorded as O, and a first gap offset distance CJ is calculated;
jumping to step 3.3 if R is less than CJ, otherwise jumping to step 3.4 and making the value of CD be R ÷ CJ;
where exp () is an exponential function with the natural logarithm as the base, L () is the distance to take 2 points, a () is the area to take the closed region, points P1, P2 are the points on the edge of the closed region MSeti where the distance O is the minimum and maximum, respectively, MAXR 0 The geometric center of gravity of the MAXR.
Although the method can identify the larger gaps, the method can still cause misjudgment or cannot identify some smaller gaps, the oil gas in the circular hollow hole extrudes the smaller gaps to cause the gaps to deviate on the image, manual correction and intervention are needed, and the characteristics of the gaps can be extracted and judged to determine whether to be included in the communicable gaps.
Step 3.2.2, taking the corner point with the minimum distance from the geometric gravity center point O of the closed region MSeti as P1, taking the corner point with the maximum distance from the geometric gravity center point O of the closed region MSeti as P2, constructing a line segment PL by the P1 and the P2, and calculating a second gap offset distance CH:
in the formula, exp () is an exponential function with a natural logarithm as a base, L () is a distance of 2 points, a (MSeti) is an area of the closed region MSeti, and R (MSeti) is a length of an outer contour of the closed region MSeti;
if the value of the second slot offset distance CH is greater than or equal to the length of the line segment PL step 3.3 is skipped, otherwise step 3.4 is skipped and the value of CD is L (P1, P2) ÷ CH.
The gaps are generally large, but because the size of the closed area is divided in the previous steps, the judgment can further classify the smaller gaps into the effective gaps, and whether the oil gas in the gaps tends to be extracted or not is judged according to the distance from the gaps to the maximum closed area.
3.3, if the value of i is less than N, increasing the value of i by 1 and skipping to the step 3.2, otherwise skipping to the step 3.5;
step 3.4, obtaining the area of the correction gap:
step 3.4.1, adding Area to the value of the first Area S1, if i is smaller than N, increasing the value of i by 1 and skipping to step 3.2, otherwise skipping to step 3.5;
and 3.5, outputting the corrected first area S1.
The correction of the area of the gap can eliminate the influence of the gap on the area of each crack caused by the fact that the oil gas in the circular cavity frequently extrudes the gap on the core slice, and the area calculation precision is improved.
Because the resolution ratio of a core scanning image obtained by laser confocal scanning is higher than that of an image obtained by scanning of a common fluorescence staining optical microscope, the obtained seam edges cannot be well distinguished due to the fact that minerals adsorb staining agents during common fluorescence staining, the problem is effectively solved by the laser confocal scanning, and a lot of hole seam structure details which cannot be obtained by scanning of the common polarization microscope are obtained; conventional methods for distinguishing core regions, such as a grayscale method, may have gaps with poor connectivity but good yield that cannot be identified, such as setting of a gap size threshold, which may be obtained according to historical experience and conventional observation methods, may affect the calculation of porosity when using confocal laser scanning photographs, and considering that a plurality of single-layer scanning photographs obtained by confocal laser scanning may be used for three-dimensional reconstruction to make core yield analysis more effective, so that correction of a single confocal laser scanning slice may make final reservoir analysis more accurate.
Further, in step 4, the sub-step of obtaining the corrected porosity is:
and recalculating the porosity according to the porosity phi = S1/S0 to obtain corrected porosity, and outputting the corrected porosity.
Preferably, the seam in step 3.4 is marked as a valid reservoir seam, a corrected scanogram is obtained, and a plurality of corrected scanograms are subjected to subsequent three-dimensional reconstruction.
Preferably, all undefined variables in the present invention may be threshold values set manually if they are not defined explicitly.
A core-based petroleum reservoir porosity estimation system, the system comprising:
an image acquisition module: scanning a scanning sheet by laser confocal scanning for obtaining a casting body slice;
an image processing module: processing a scanning sheet obtained by laser confocal scanning, and outputting a plurality of closed areas;
a data processing module: and executing the steps of the core-based petroleum reservoir porosity measurement and calculation method to obtain the porosity.
In a third aspect, the present invention provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, carries out the steps of the method for core-based porosity estimation of a petroleum reservoir as provided in the first aspect of the present invention.
In a fourth aspect, the present invention provides an electronic device comprising: a memory having a computer program stored thereon; a processor for executing the computer program in the memory to implement the steps of the core-based petroleum reservoir porosity estimation method provided by the invention.
Compared with the prior art, the invention has the following beneficial technical effects:
the laser confocal scanning obtains a high-resolution rock core scanning photo, and the scanning photo is corrected according to the geometric shape and size of a pore to obtain more accurate porosity, so that more accurate information is provided for oil-gas analysis, and the problem of analysis errors caused by more photo details when the laser confocal scanning is used for rock core analysis is solved.
Drawings
FIG. 1 is a flow chart of a method for measuring and calculating porosity of a petroleum reservoir based on a core according to the present invention;
fig. 2 is a schematic block diagram of a core-based petroleum reservoir porosity estimation system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.
It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art in light of the foregoing description are intended to be included within the scope of the invention. The specific process parameters and the like of the following examples are also merely examples within a suitable range, i.e., those skilled in the art can select within a suitable range by the description herein, and are not limited to the specific values exemplified below.
The following exemplarily illustrates a method for measuring and calculating the porosity of a petroleum reservoir based on a rock core provided by the invention.
Referring to fig. 1, which is a flow chart of a core-based petroleum reservoir porosity estimation method, a core-based petroleum reservoir porosity estimation method according to an embodiment of the present invention is described below with reference to fig. 1, the method including the steps of:
step 1, drilling a rock core and manufacturing a casting body slice;
step 2, scanning the casting body slice to obtain a scanning picture, and calculating the porosity;
step 3, correcting the porosity according to the pore-gap relation;
and 4, obtaining the corrected porosity.
Further, in step 1, the core is drilled, and the substep of manufacturing the casting sheet is as follows:
and drilling a standard core pillar sample with the diameter of 25mm, injecting an epoxy resin dye-dipping agent into the standard core pillar sample, and grinding the rock slice after the epoxy resin dye-dipping agent is cured.
Further, in step 2, scanning the casting slice to obtain a scanning picture, and the sub-step of calculating the porosity is as follows:
scanning the cast body slice of the rock core by using a laser confocal microscope to obtain a scanning slice; carrying out graying processing on the scanning sheet;
obtaining an edge curve through an edge detection operator, dividing the scanning slice into a plurality of closed regions by using the edge curve, setting a threshold of the area of each closed region as a gap size threshold THRS, and forming a first region set by regions with the areas larger than the gap size threshold in each closed region;
recording the total area of all closed areas in the first area set as a first area S1, enabling the core area S0 to be the view area of the current scanning slice, and calculating the porosity phi = S1/S0; if S1 is larger than 0, the closed region with the largest area in the first region set is MAXR, and the geometric gravity center point of the MAXR is MAXR 0 。
Further, in step 3, the sub-step of correcting the porosity according to the pore-gap relationship is as follows:
the closed areas in the MSet are sorted in a descending order according to the size by using a hole seam set MSet formed by closed areas which do not belong to the first area set in each closed area of the scanning piece, wherein MSeti is used as the ith closed area in the set, and i is a positive integer; initializing a variable i to be 2, setting the size of a slot set MSet to be N, and setting i to be in an element of [1, N ]; setting a variable as a correction ratio CD;
step 3.1, taking the geometric gravity center point of the closed area with the largest area in the scanning sheet as a reference point PA, and increasing the value of i by 1;
and 3.2, carrying out corner point detection on the closed region MSeti, and skipping to the step 3.2.1 if the number of corner points is less than 3, or skipping to the step 3.2.2.
The number of the angular points is set to 3 so as to be used for classifying the closed area, gaps with the number of the angular points being less than 3 are generally small, correction is performed after circle identification is applicable, gaps with the number of the angular points being more than 3 are generally large and are not applicable to circle detection, and the size of the closed area is divided by the previous steps, so that the processing steps are separated.
The obtained scanning sheet can be divided into a plurality of areas, the size and the geometric shape of the areas can influence reservoir analysis, the further classification of the divided areas is helpful for enabling the correction process to be more accurate, and whether the oil gas in the gap tends to be extracted or not is judged according to the distance from the gap to the maximum closed area.
Step 3.2.1, performing circle recognition (namely Hough circle detection) on the closed area MSeti to detect a circle, wherein the detected circle is surrounded by the closed area and has the maximum radius (because in a core of an oil and gas reservoir, a circular cavity is frequently formed on a core slice caused by oil and gas erosion or natural storage of oil and gas (bubbles or the oil and gas in the core are generally circular), and the oil and gas extrusion gap in the circular cavity causes the gap to shift on an image, so that the gap position needs to be corrected); the circle center of the circle is C, the radius of the circle is R, the geometric gravity center point of the current closed area is recorded as O, and a first gap offset distance CJ is calculated;
jumping to step 3.3 if R is less than CJ, otherwise jumping to step 3.4 and making the value of CD be R ÷ CJ;
where exp () is an exponential function with the natural logarithm as the base, L () is the distance to take 2 points, a () is the area to take the closed region, points P1, P2 are the points on the edge of the closed region MSeti where the distance O is the minimum and maximum, respectively, MAXR 0 The geometric center of gravity of the MAXR.
The gaps are generally small, misjudgment may be caused by division of the traditional method, manual correction and intervention are needed, and whether the gaps can be classified into the communicated gaps can be determined after the characteristics of the gaps are extracted and judged.
Step 3.2.2, taking the corner point with the minimum distance from the geometric center of gravity O of the closed region MSeti as P1, taking the corner point with the maximum distance from the geometric center of gravity O of the closed region MSeti as P2, constructing a line segment PL by the P1 and the P2, and calculating a second gap offset distance CH:
in the formula, exp () is an exponential function with a natural logarithm as a base, L () is a distance of 2 points, a (MSeti) is an area of the closed region MSeti, and R (MSeti) is a length of an outer contour of the closed region MSeti;
if the value of the second slot offset distance CH is greater than or equal to the length of the line segment PL step 3.3 is skipped, otherwise step 3.4 is skipped and the value of CD is L (P1, P2) ÷ CH.
The gaps are generally large, but because the size of the closed area is divided in the previous steps, the judgment can further classify the smaller gaps into the effective gaps, and whether the oil gas in the gaps tends to be extracted or not is judged according to the distance from the gaps to the maximum closed area.
3.3, if i is smaller than N, increasing the value of i by 1 and skipping to the step 3.2, otherwise skipping to the step 3.5;
step 3.4, obtaining the area of the correction gap:
step 3.4.1, adding the value of Area into the first Area S1, if i is smaller than N, increasing the value of i by 1 and skipping to step 3.2, otherwise skipping to step 3.5;
and 3.5, outputting the corrected first area S1.
The correction of the area of the gap can eliminate the influence of the gap on the area of each crack caused by the fact that the oil gas in the circular cavity frequently extrudes the gap on the core slice, and the area calculation precision is improved.
The resolution ratio of a core scanning image obtained by laser confocal scanning is higher than that of an image obtained by scanning of a common fluorescence dyeing optical microscope, the obtained slit edges cannot be well distinguished due to the fact that minerals adsorb a dyeing agent during common fluorescence dyeing, the problem is effectively solved by the laser confocal scanning, and a lot of hole and slit structure details which cannot be obtained by scanning of the common polarization microscope are obtained; conventional methods for distinguishing core regions, such as a grayscale method, may have gaps with poor connectivity but good yield, which cannot be identified, such as setting of a gap size threshold, which may be obtained according to historical experience and conventional observation methods, and may affect the calculation of porosity when using a confocal laser scanning photograph, and considering that a plurality of single-layer scanning photographs obtained by confocal laser scanning may be used for three-dimensional reconstruction to make core yield analysis more effective, a single confocal laser scanning slice may be corrected to make final reservoir analysis more accurate.
Further, in step 4, the sub-step of obtaining the corrected porosity is:
and recalculating the porosity according to the porosity phi = S1/S0 to obtain corrected porosity, and outputting the corrected porosity.
Preferably, the seam in step 3.4 is marked as a valid reservoir seam, a corrected scanogram is obtained, and a plurality of corrected scanograms are subjected to subsequent three-dimensional reconstruction.
Preferably, all undefined variables in the present invention may be thresholds that are manually set if they are not explicitly defined.
Preferably, all undefined variables in the present invention may be threshold values set manually if they are not defined explicitly.
Fig. 2 is a schematic block diagram illustrating a structure of a core-based petroleum reservoir porosity estimation system according to an embodiment of the present invention.
A core-based petroleum reservoir porosity estimation system, the system comprising:
an image acquisition module: scanning a scanning sheet by laser confocal scanning for obtaining a casting body slice;
an image processing module: processing a scanning sheet obtained by laser confocal scanning, and outputting a plurality of closed areas;
a data processing module: and executing the steps of the method for measuring and calculating the porosity of the petroleum reservoir based on the core to obtain the porosity.
Compared with the prior art, the invention has the following beneficial technical effects:
the laser confocal scanning obtains a high-resolution rock core scanning photo, and the scanning photo is corrected according to the geometric shape and size of a pore to obtain more accurate porosity, so that more accurate information is provided for oil-gas analysis, and the problem of analysis errors caused by more photo details when the laser confocal scanning is used for rock core analysis is solved.
The petroleum reservoir porosity measuring and calculating system based on the core can be operated in computing equipment such as desktop computers, notebook computers, palm computers and cloud servers. The core-based petroleum reservoir porosity estimation system can be operated by a system comprising, but not limited to, a processor and a memory. Those skilled in the art will appreciate that the example is merely illustrative of a core-based oil reservoir porosity estimation system and does not constitute a limitation of a core-based oil reservoir porosity estimation system, and may include more or less components than, or in combination with, certain components, or different components, e.g., the core-based oil reservoir porosity estimation system may further include input and output devices, network access devices, buses, etc.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, the processor being the control center of the core based oil reservoir porosity estimation system operating system, and various interfaces and lines connecting the various parts of the entire core based oil reservoir porosity estimation system operating system.
The memory may be used to store the computer programs and/or modules, and the processor may implement the various functions of the core-based petroleum reservoir porosity estimation system by executing or executing the computer programs and/or modules stored in the memory and invoking the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
Although the present invention has been described in considerable detail and with reference to certain illustrated embodiments, it is not intended to be limited to any such details or embodiments or any particular embodiment, so as to effectively encompass the intended scope of the invention. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalent modifications thereto.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and alterations to these embodiments may be made without departing from the principles and spirit of the invention.
Claims (8)
1. A method for measuring and calculating the porosity of a petroleum reservoir based on a rock core is characterized by comprising the following steps:
step 1, drilling a rock core and manufacturing a casting body slice;
step 2, scanning the casting body slice to obtain a scanning picture, and calculating the porosity;
step 3, correcting the porosity according to the pore-gap relation;
and 4, obtaining the corrected porosity.
2. The method for measuring and calculating the porosity of the petroleum reservoir based on the rock core as claimed in claim 1, wherein in the step 1, the rock core is drilled, and the substep of manufacturing the casting body slice is as follows:
and drilling a standard core pillar sample with the diameter of 25mm, injecting an epoxy resin dye-dipping agent into the standard core pillar sample, and grinding the rock slice after the epoxy resin dye-dipping agent is cured.
3. The method for measuring and calculating porosity of petroleum reservoir based on core as claimed in claim 1, wherein in step 2, scanning the casting body slice to obtain scanning photo, the substep of calculating porosity is:
scanning the cast body slice of the rock core by using a laser confocal microscope to obtain a scanning slice; carrying out graying treatment on the scanning film;
obtaining an edge curve through an edge detection operator, dividing a scanning sheet into a plurality of closed regions by the edge curve, setting a threshold value of the area of each closed region as a gap size threshold value THRS, and forming a first region set by the region of each closed region, the area of which is larger than the gap size threshold value;
in the first region setThe total area of all closed areas is a first area S1, the area S0 of a rock core is the view area of the current scanning sheet, and the porosity phi = S1/S0 is calculated; if S1 is larger than 0, the closed area with the largest area in the first area set is MAXR, and the geometric gravity center point of the MAXR is MAXR 0 。
4. A method for measuring and calculating porosity of a core-based petroleum reservoir according to claim 3, wherein in the step 3, the sub-step of correcting the porosity according to the pore-gap relation is as follows:
the closed areas in the MSet are sorted in a descending order according to the size by using a hole seam set MSet formed by closed areas which do not belong to the first area set in each closed area of the scanning piece, wherein MSeti is used as the ith closed area in the set, and i is a positive integer; initializing a variable i to be 2, setting the size of a slot set MSet to be N, and setting i to be in an element of [1, N ]; setting a variable as a correction ratio CD;
step 3.1, taking the geometric gravity center point of the closed area with the largest area in the scanning sheet as a reference point PA, and increasing the value of i by 1;
step 3.2, carrying out corner point detection on the closed region MSeti, if the number of corner points is less than 3, skipping to step 3.2.1, otherwise skipping to step 3.2.2;
step 3.2.1, performing circle identification on the closed region MSeti to detect a circle, wherein the detected circle is surrounded by the closed region and the radius is maximized; the circle center of the circle is C, the radius of the circle is R, the geometric center of gravity of the current closed area is recorded as O, and a first gap offset distance CJ is calculated;
if R is less than CJ jump step 3.3, otherwise jump step 3.4 and make the value of CD as R ÷ CJ;
where exp () is an exponential function with the natural logarithm as the base, L () is the distance to take 2 points, a () is the area to take the closed region, points P1, P2 are the points on the edge of the closed region MSeti where the distance O is the minimum and maximum, respectively, MAXR 0 Geometric center of gravity point of MAXR;
step 3.2.2, taking the corner point with the minimum distance from the geometric gravity center point O of the closed region MSeti as P1, taking the corner point with the maximum distance from the geometric gravity center point O of the closed region MSeti as P2, constructing a line segment PL by the P1 and the P2, and calculating a second gap offset distance CH:
in the formula, exp () is an exponential function with a natural logarithm as a base, L () is a distance of 2 points, a (MSeti) is an area of a closed region MSeti, and R (MSeti) is a length of an outer contour of the closed region MSeti;
skipping step 3.3 if the value of the second slot offset distance CH is greater than or equal to the length of the line segment PL, otherwise skipping step 3.4 and making the value of CD L (P1, P2) ÷ CH;
3.3, if i is smaller than N, increasing the value of i by 1 and skipping to the step 3.2, otherwise skipping to the step 3.5;
step 3.4, obtaining the area of a correction gap:
step 3.4.1, adding the value of Area into the first Area S1, if i is smaller than N, increasing the value of i by 1 and skipping to step 3.2, otherwise skipping to step 3.5;
and 3.5, outputting the corrected first area S1.
5. The method for measuring and calculating the porosity of the petroleum reservoir based on the core as claimed in claim 4, wherein in the step 4, the sub-step of obtaining the corrected porosity is as follows: and recalculating the porosity according to the porosity phi = S1/S0 to obtain corrected porosity, and outputting the corrected porosity.
6. A core-based petroleum reservoir porosity estimation system, the system comprising:
an image acquisition module: scanning slices are obtained by laser confocal scanning for obtaining the casting body slices;
an image processing module: processing a scanning sheet obtained by laser confocal scanning, and outputting a plurality of closed areas;
a data processing module: the method for measuring and calculating the porosity of the petroleum reservoir based on the core as claimed in claims 1 to 5 is carried out to obtain the porosity.
7. A computer-readable storage medium, on which a computer program is stored, wherein the program, when executed by a processor, implements the steps of the method for measuring and calculating porosity of a core-based petroleum reservoir according to any one of claims 1 to 5.
8. An electronic device, comprising: a memory having a computer program stored thereon; a processor for executing the computer program in the memory to implement the steps of the core-based oil reservoir porosity estimation method according to any one of claims 1 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310145517.9A CN115876668B (en) | 2023-02-22 | 2023-02-22 | Petroleum reservoir porosity measuring and calculating method based on rock core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310145517.9A CN115876668B (en) | 2023-02-22 | 2023-02-22 | Petroleum reservoir porosity measuring and calculating method based on rock core |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115876668A true CN115876668A (en) | 2023-03-31 |
| CN115876668B CN115876668B (en) | 2023-05-05 |
Family
ID=85761450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310145517.9A Active CN115876668B (en) | 2023-02-22 | 2023-02-22 | Petroleum reservoir porosity measuring and calculating method based on rock core |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115876668B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104297131A (en) * | 2014-11-04 | 2015-01-21 | 中国石油大学(华东) | Method for correcting porosity of gravelly sandstone reservoir |
| US20160124115A1 (en) * | 2014-10-23 | 2016-05-05 | Chevron U.S.A. Inc. | System and Method of Pore Type Classification for Petrophysical Rock Typing |
| CN105628580A (en) * | 2015-12-21 | 2016-06-01 | 中国石油大学(华东) | Reservoir false crack identification and physical property correction method |
| CN106501145A (en) * | 2016-09-18 | 2017-03-15 | 中国石油大学(北京) | The bearing calibration of shale gas reservoir numerical simulation |input paramete and device |
| CN109100281A (en) * | 2018-09-10 | 2018-12-28 | 中国石油天然气股份有限公司 | Oil saturation determination method and device |
| CN113222923A (en) * | 2021-04-30 | 2021-08-06 | 广东石油化工学院 | Method for identifying crack type based on core photo |
| CN114112829A (en) * | 2020-08-27 | 2022-03-01 | 中国石油化工股份有限公司 | Correction method for carbonate reservoir porosity calculation |
| CN114624163A (en) * | 2022-04-18 | 2022-06-14 | 成都理工大学 | Overburden pressure pore-permeability test-based muddiness zeolite clastic rock reservoir physical property correction method |
| US20220341835A1 (en) * | 2021-04-22 | 2022-10-27 | Saudi Arabian Oil Company | Methods and Systems for Determining Reservoir and Fracture Properties |
-
2023
- 2023-02-22 CN CN202310145517.9A patent/CN115876668B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160124115A1 (en) * | 2014-10-23 | 2016-05-05 | Chevron U.S.A. Inc. | System and Method of Pore Type Classification for Petrophysical Rock Typing |
| CN104297131A (en) * | 2014-11-04 | 2015-01-21 | 中国石油大学(华东) | Method for correcting porosity of gravelly sandstone reservoir |
| CN105628580A (en) * | 2015-12-21 | 2016-06-01 | 中国石油大学(华东) | Reservoir false crack identification and physical property correction method |
| CN106501145A (en) * | 2016-09-18 | 2017-03-15 | 中国石油大学(北京) | The bearing calibration of shale gas reservoir numerical simulation |input paramete and device |
| CN109100281A (en) * | 2018-09-10 | 2018-12-28 | 中国石油天然气股份有限公司 | Oil saturation determination method and device |
| CN114112829A (en) * | 2020-08-27 | 2022-03-01 | 中国石油化工股份有限公司 | Correction method for carbonate reservoir porosity calculation |
| US20220341835A1 (en) * | 2021-04-22 | 2022-10-27 | Saudi Arabian Oil Company | Methods and Systems for Determining Reservoir and Fracture Properties |
| CN113222923A (en) * | 2021-04-30 | 2021-08-06 | 广东石油化工学院 | Method for identifying crack type based on core photo |
| CN114624163A (en) * | 2022-04-18 | 2022-06-14 | 成都理工大学 | Overburden pressure pore-permeability test-based muddiness zeolite clastic rock reservoir physical property correction method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115876668B (en) | 2023-05-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Chandra et al. | A critical review on pore to continuum scale imaging techniques for enhanced shale gas recovery | |
| CN106323836B (en) | Borehole wall permeability calculation method and device | |
| CN106716114B (en) | Porous media analysis systems and methods | |
| WO2017114443A1 (en) | Method and device for determining dissolution degree of karst reservoir | |
| Ruzyla | Characterization of pore space by quantitative image analysis | |
| CN107655908B (en) | Method and device for constructing digital core | |
| US20140019054A1 (en) | Digital rock analysis systems and methods with reliable multiphase permeability determination | |
| CN102037492A (en) | Image data processing | |
| CN103400139A (en) | Method for identifying concrete crack characteristic information | |
| Peng et al. | Evaluation of the pore structure of tight sandstone reservoirs based on multifractal analysis: A case study from the Kepingtage Formation in the Shuntuoguole uplift, Tarim Basin, NW China | |
| CN112686917A (en) | Digital core modeling method and device for improving core heterogeneity representation precision | |
| Ma et al. | Objective-Driven Solid-Surface-Roughness Characterization for Enhanced Nuclear-Magnetic-Resonance Petrophysics | |
| CN115876668A (en) | Petroleum reservoir porosity measuring and calculating method based on core | |
| Singer et al. | 2D Surface Roughness Quantification for Enhanced Petrophysical Applications | |
| Howard et al. | Uncertainty quantification in image segmentation for image-based rock physics in a shaly sandstone | |
| CN111738978B (en) | Reservoir pore throat connectivity evaluation method and device, electronic equipment and storage medium | |
| CN108320307B (en) | Method and device for determining effective unit volume of reservoir rock sample | |
| CN114529771B (en) | Shale large-view-area image classification method based on machine learning | |
| US11566992B2 (en) | Method and device for characterizing microbial carbonate pores, and server | |
| CN110593864B (en) | Method and device for identifying fluid by using nuclear magnetism-sound wave | |
| US11530999B2 (en) | Pore contribution corrected quantifying of surface roughness | |
| CN112231881A (en) | Matrix permeability calculation method and system | |
| CN117309923A (en) | On-site rock debris scanning representative analysis method and device | |
| CN114065828A (en) | Sandstone corrosion type judging method and device, electronic equipment and medium | |
| CN113050188A (en) | Method and device for determining effective opening of microcrack based on tight reservoir |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |