CN116953012A - Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks - Google Patents
Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks Download PDFInfo
- Publication number
- CN116953012A CN116953012A CN202311203460.XA CN202311203460A CN116953012A CN 116953012 A CN116953012 A CN 116953012A CN 202311203460 A CN202311203460 A CN 202311203460A CN 116953012 A CN116953012 A CN 116953012A
- Authority
- CN
- China
- Prior art keywords
- crack
- rock sample
- dimensional nuclear
- nuclear magnetic
- spectrum
- 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 68
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 title claims abstract description 35
- 239000011435 rock Substances 0.000 claims abstract description 105
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 55
- 238000001228 spectrum Methods 0.000 claims abstract description 48
- 238000002474 experimental method Methods 0.000 claims abstract description 46
- 230000005311 nuclear magnetism Effects 0.000 claims abstract description 35
- 238000002591 computed tomography Methods 0.000 claims abstract description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000006073 displacement reaction Methods 0.000 claims abstract description 19
- 238000005516 engineering process Methods 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 238000012512 characterization method Methods 0.000 claims abstract description 8
- 238000012545 processing Methods 0.000 claims abstract description 7
- 239000011159 matrix material Substances 0.000 claims description 47
- 239000011148 porous material Substances 0.000 claims description 45
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical class [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 18
- 239000012530 fluid Substances 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 13
- 238000011161 development Methods 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000011156 evaluation Methods 0.000 abstract description 6
- 239000003921 oil Substances 0.000 description 42
- 238000005481 NMR spectroscopy Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 2
- DIOQZVSQGTUSAI-UHFFFAOYSA-N decane Chemical compound CCCCCCCCCC DIOQZVSQGTUSAI-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000295 fuel oil Substances 0.000 description 2
- 238000009738 saturating Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910002056 binary alloy Inorganic materials 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000011158 quantitative evaluation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N24/00—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects
- G01N24/08—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects by using nuclear magnetic resonance
- G01N24/081—Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
- G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
-
- 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
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- General Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Analytical Chemistry (AREA)
- High Energy & Nuclear Physics (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Pulmonology (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Geochemistry & Mineralogy (AREA)
- Radiology & Medical Imaging (AREA)
- Theoretical Computer Science (AREA)
- Remote Sensing (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
The application discloses a method for calibrating two-dimensional nuclear magnetic distribution of a carbonate light oil reservoir crack, which comprises the following steps: selecting a rock sample, and processing the rock sample based on a saturation method to obtain a saturated water rock sample and a saturated oil rock sample; CT scanning experiments are carried out on saturated water rock samples to obtain rock sample cracks, and CT scanning images of the aperture of the cracks are converted into bar charts; carrying out a gas displacement experiment on the saturated oil rock sample to obtain a gas displacement rock sample; respectively carrying out two-dimensional nuclear magnetic scanning experiments on a saturated oil rock sample and a gas flooding rock sample, and then obtaining a crack two-dimensional nuclear magnetic T1-T2 spectrum based on a difference spectrum method; and calibrating the aperture-time quantitative conversion relation of the crack based on the two-dimensional nuclear magnetism T1-T2 spectrum of the crack and the histogram of the aperture of the crack, so as to obtain the quantitative characterization distribution of the two-dimensional nuclear magnetism of the crack. The application draws the two-dimensional nuclear magnetic distribution map of the crack, fills the application blank of the two-dimensional nuclear magnetic technology in the crack evaluation of the light oil reservoir of the crack carbonate rock, and has scientificity and universality.
Description
Technical Field
The application belongs to the technical field of oil reservoir exploration and development, and particularly relates to a method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks.
Background
The ocean carbonate rock oil gas resources are rich, cracks are the main storage space and migration channels, and clear crack distribution characteristics are key problems for evaluating the ocean carbonate rock reservoir. Currently, crack evaluation methods are mainly classified into two categories: 1) Direct observation methods, such as an optical microscope, a scanning electron microscope and the like, wherein the observation result is a two-dimensional image and semi-quantitative; 2) The indirect observation method mainly comprises mercury intrusion, one-dimensional nuclear magnetic resonance (NMR T2), CT scanning and the like, and the test result is a quantitative pore size distribution curve. In the method, only NMR and CT can realize nondestructive testing of samples, but CT test can only be carried out in-house test, and underground test can not be carried out; the one-dimensional nuclear magnetic resonance NMR only has one function of T2, and has no T1 function, so that even if the underground test can be carried out, the two-dimensional nuclear magnetic pattern plate cannot be obtained.
At present, the two-dimensional nuclear magnetic technology is mature, and consists of two parts, namely T2 and T1, wherein T1 is related to the property of fluid, T2 is related to the aperture, and compared with the one-dimensional nuclear magnetic technology, the application is wider. However, a two-dimensional nuclear magnetic evaluation plate for carbonate cracks and a related drawing technology are not available at present, wherein oil properties (light oil or heavy oil) are key factors influencing the nuclear magnetic T1-T2 spectrum, so that a method for calibrating two-dimensional nuclear magnetic distribution of the carbonate light oil cracks is needed to be provided.
Disclosure of Invention
The application aims to provide a method for calibrating two-dimensional nuclear magnetic distribution of a carbonate light oil reservoir fracture, which uses a full-diameter sample to replace a traditional centimeter-level plunger to develop KI-CT um Experiment, overcome the problem of fracture loss caused by strong heterogeneity, provide accurate fracture mark for nuclear magnetic experimentSetting parameters; and drawing a crack two-dimensional nuclear magnetism T1-T2 distribution chart, and filling the application blank of the two-dimensional nuclear magnetism technology in evaluating the cracks of the carbonate rock light oil reservoir so as to solve the problems in the prior art.
In order to achieve the above purpose, the application provides a method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks, which comprises the following steps:
selecting a rock sample, and processing the rock sample based on a saturation method to obtain a saturated water rock sample and a saturated oil rock sample;
performing CT scanning experiments on the saturated water rock sample to obtain rock sample cracks, and converting CT scanning images of crack apertures into bar charts;
performing a gas displacement experiment on the saturated oil rock sample to obtain a gas displacement rock sample;
respectively carrying out two-dimensional nuclear magnetic scanning experiments on a saturated oil rock sample and a gas flooding rock sample, and then obtaining a crack two-dimensional nuclear magnetic T1-T2 spectrum based on a difference spectrum method;
calibrating a fracture aperture-time quantitative conversion relation based on the fracture two-dimensional nuclear magnetism T1-T2 spectrum and a histogram of the fracture aperture;
and obtaining the quantitative characterization distribution of the two-dimensional nuclear magnetism of the crack based on the quantitative conversion relation of the aperture and the time of the crack.
Optionally, the process of selecting a rock sample comprises: and preparing a full-diameter sample with a preset size based on the crack development carbonate rock to obtain a rock sample.
Optionally, the process of obtaining a saturated water rock sample and a saturated oil rock sample comprises: drying, weighing and measuring the volume of the rock sample to obtain a first mass and a total volume; selecting a part of dried rock sample, vacuumizing, and pressurizing a saturated potassium iodide solution for 24 hours to obtain a saturated water rock sample; and (5) vacuumizing the rest rock sample, and pressurizing saturated light oil for 24 hours to obtain a saturated oil rock sample.
Optionally, the process of obtaining a rock sample fracture comprises: performing CT scanning experiments on the saturated water rock sample to obtain a plurality of hole seams; and distinguishing the hole and the slit based on a digital image processing technology to obtain a matrix hole and a slit.
Optionally, the process after obtaining the rock sample fracture further comprises: obtaining matrix pore porosities corresponding to the matrix pores, and performing difference on CT porosities and matrix pore porosities to obtain crack porosities; and obtaining the fracture volume based on the product of the fracture porosity and the total volume of the rock sample.
Optionally, the process after performing the CT scan experiment further comprises: and obtaining the mass of the saturated water rock sample as a second mass, obtaining the total porosity of the rock sample based on the first mass, the second mass, the total volume of the rock sample and the fluid density of the saturated water rock sample, and correcting the crack content based on the ratio of the crack porosity to the total porosity.
Optionally, the process of conducting the gas displacement experiment on the saturated oil rock sample comprises the following steps: placing a saturated oil rock sample into a clamp holder, then adding confining pressure for fixation, and injecting gas into the saturated oil rock sample; and placing a measuring cylinder at the outlet end of the clamp holder to collect liquid discharged from the hole, continuing the gas displacement experiment when the liquid output of the outlet end is smaller than the volume of the crack, and ending the gas displacement experiment when the liquid output of the outlet end is equal to the volume of the crack to obtain the gas displacement rock sample.
Optionally, the process of obtaining the two-dimensional nuclear magnetic T1-T2 spectrum of the fracture comprises: respectively carrying out two-dimensional nuclear magnetic scanning experiments on the saturated oil rock sample and the gas displacement rock sample to obtain a corresponding hole seam integral two-dimensional nuclear magnetic T1-T2 spectrum and a matrix hole two-dimensional nuclear magnetic T1-T2 spectrum; the integral two-dimensional nuclear magnetism T1-T2 spectrum of the hole seam and the two-dimensional nuclear magnetism T1-T2 spectrum of the matrix hole are subjected to difference to obtain a crack two-dimensional nuclear magnetism T1-T2 spectrum; the two-dimensional nuclear magnetism T1-T2 spectrum of the crack comprises a longitudinal relaxation spectrum of the crack in an oil-containing state and a transverse relaxation spectrum of the crack in the oil-containing state.
Optionally, the process of calibrating the fracture pore size-time quantitative conversion relation comprises the following steps: pattern matching is carried out on a histogram based on the aperture of the crack and the transverse relaxation spectrum of the crack in the oil-containing state, and a plurality of crossing points are extracted; and establishing a quantitative conversion relation between the aperture of the crack and the time based on the plurality of crossing points.
Optionally, the process of obtaining the two-dimensional nuclear magnetic quantitative characterization distribution of the fracture comprises the following steps: projecting the matrix pore two-dimensional nuclear magnetism T1-T2 spectrum to a coordinate system where the crack two-dimensional nuclear magnetism T1-T2 spectrum is located, drawing a pore two-dimensional nuclear magnetism spectrum under the same coordinate system, marking a crack aperture value at a crack in the pore two-dimensional nuclear magnetism spectrum, and marking a matrix pore aperture value at a matrix pore to obtain quantitative characterization distribution of the crack two-dimensional nuclear magnetism.
The application has the technical effects that:
according to the application, a full-diameter sample is used for carrying out experiments instead of a traditional centimeter-level plunger, so that the problem of crack loss caused by strong heterogeneity is solved; CT scanning is carried out on a saturated potassium iodide sample, so that the separation of holes and slits is facilitated, and matrix pores can be accurately extracted under the condition of allowing resolution; the two-dimensional nuclear magnetism T1-T2 distribution plate of the crack is drawn, the application blank of the two-dimensional nuclear magnetism technology in crack evaluation of the light oil reservoir of the crack carbonate rock is filled, and the method has scientificity and universality.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a schematic diagram of a CT porosity versus total porosity model in an embodiment of the present application;
fig. 2 is a schematic flow chart of a method for calibrating two-dimensional nuclear magnetic distribution of a carbonate light oil reservoir fracture in an embodiment of the application.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.
Example 1
As shown in fig. 1-2, the method for calibrating two-dimensional nuclear magnetic distribution of a carbonate light oil reservoir fracture in this embodiment includes the following steps:
s1: the saturation method calculates the total porosity.
S11: and (5) preparing a rock sample. The crack-developing carbonate rock is selected to prepare a large-size sample (length 5-7cm, diameter 6cm or 10 cm).
S12: and (5) drying the rock sample. Drying and standing the rock sample at 200 ℃ to room temperature for standby, and weighing the weight m of the dried rock sample d (g) Measuring total volume V b （g/cm 3 ）。
S13: the rock sample is saturated.
S131: saturated water. The dried sample was evacuated and then pressurized (32 MPa) with a saturated aqueous potassium iodide solution (2000-5000 ppm) for 24 hours.
S132: saturated oil. Vacuum pumping the dried sample, pressurizing (32 MPa) saturated light oil (such as n-decane) for 24 hours, and simulating light oil reservoir (density)<0.87g/cm 3 ）。
S133: the saturated fluid experiment sequence is not changeable, the saturated water CT scanning experiment is firstly carried out to calibrate the crack parameters, and then the saturated oil nuclear magnetic resonance experiment is carried out to obtain the fluid distribution spectrum.
S14: calculating the total porosity t 。
Ø t =((m s -m d )/ρ)/V b (equation 1)
Wherein ρ is the saturated water fluid density
In theory, the same sample has unchanged pore space, the porosity is the same as obtained by completely saturating any fluid, and in order to avoid the error in calculation of the porosity caused by incomplete saturation, the saturated water mass m is used in the embodiment s Calculating t 。
S2：KI-CT um Scan quantified fracture parameters.
S21: saturated KI sample micrometer CT scanning (KI-CT) um ) And (5) experiment.
S22: dividing the aperture by digital image processing technology, and calculating the aperture r of the matrix aperture m (matrix pore 2) and crack pore diameter r f (crack 3).
In fig. 1 "matrix pore 1" represents a matrix pore lost below the resolution of the CT scanner, with a porosity of one 1 The method comprises the steps of carrying out a first treatment on the surface of the "matrix pore2 "represents the matrix porosity identified by CT scan, which porosity is 2 2 The method comprises the steps of carrying out a first treatment on the surface of the "crack 3" represents all cracks (parallel) identified by CT scan 3 =Ø f ）。
The matrix pores below the resolution of the CT instrument are regarded as skeletons, affected by the resolution, so the S21 result is not a true complete pore distribution of the rock sample, belonging to pseudo-pore distribution. According to the embodiment, the porosity is calculated by a saturated fluid method, so that the problem of inaccurate calculation of the crack content caused by the loss of the porosity in CT scanning is solved, and meanwhile, the problem of rapid increase of experimental cost caused by excessive invalid CT scanning is avoided.
S23: will r f The spectrum is converted into a histogram.
S24: calculation of crack porosity f 。
Ø CT =Ø 2 +Ø 3 （Ø CT <Ø t ) (equation 2)
Ø f =Ø 3 (equation 3)
Wherein, is a cylinder 2 The "matrix pore 2" porosity, representing the amount of matrix porosity identified by CT scan; is (are) CT Is CT porosity.
S25: correcting crack content S f 。
S f =Ø 3 /Ø t (equation 4)
By using 3 With a root of common CT The ratio of (2) is inaccurate in calculating the crack content, and correction of the crack content is required.
S26: calculating the fracture volume V f 。
V f =V b *Ø 3 (equation 5)
S3: the gas drive experiment empties the fracture fluid.
S31: the method for measuring the experimental fluid of gas drive. After the full-diameter rock sample is put into the clamp holder, confining pressure is applied to fix the rock sample (not less than 5 MPa), and a measuring cylinder is placed at the outlet end of the clamp holder to collect liquid discharged from the hole. An air pipe is added at the position of the outlet end close to the clamp holder, and air is blown at fixed time, so that the phenomenon that the liquid is stuck to the pipe wall of the outlet end to influence the metering of the liquid outlet volume V is prevented.
In a pore-gap binary system, the permeability of the fracture (hypertonic zone) is much higher than the matrix pores (hypotonic zone). The external injection gas will preferentially drive the fluid in the fracture out of the rock, affected by the osmotic differences. Under the condition that special treatment (such as back pressure setting and semi-permeable baffle placement) is not carried out on the outlet end, gas only passes through cracks (dominant seepage channels) and cannot enter matrix pores, which is the theoretical basis of gas-driven crack oil experiments.
And when only the matrix pores contain liquid and the cracks do not contain liquid, the gas-liquid-driving experiment is completed. The ratio of the content of the flooding fluid to the content of the saturation fluid is equal to the fracture content S f The volume V of the driving fluid is equal to the fracture volume V f 。
S32: the size of the carbonate rock cracks is relatively large, and no back pressure is set in the experiment.
S4: end of displacement experiment condition.
S41: the outlet liquid volume V is smaller than the crack volume V f And (3) continuing the gas drive experiment (N).
S42: the outlet liquid volume V of the outlet end reaches the crack volume V f And (3) ending the gas drive experiment (Y).
S5: two-dimensional nuclear magnetic scanning experiments.
S51: saturated oil rock sample two-dimensional nuclear magnetic scanning experiment is carried out, and a hole seam integral two-dimensional nuclear magnetic T1-T2 spectrum T is obtained mf 。
S52: the gas displacement rock sample two-dimensional nuclear magnetic scanning experiment is carried out to obtain matrix holes, namely matrix hole 1 and matrix hole 2 shown in figure 1, and a two-dimensional nuclear magnetic T1-T2 spectrum T is obtained m 。
S53: the nuclear magnetic instrument is a large-caliber (150 mm) two-dimensional nuclear magnetic resonance instrument.
S6: differential spectrum method for calculating two-dimensional nuclear magnetism T1-T2 distribution T of crack f 。
S61：T mf And T is m Obtaining a crack T1-T2 time distribution map T under the filling state of the light oil by making a difference f 。T f Comprising a longitudinal relaxation spectrum T1 of a crack in an oil-containing state f And a crack transverse relaxation spectrum T2 in the oil-containing state f Two parts.
S62: calibrated fracture aperture-time quantitative conversion relation T2 f -r f ”。
r f Histogram and T2 f Pattern matching is performed, and at least 4 (T2 f ,r f ) Crossing point, establishing a crack aperture-time quantitative conversion relation T2 f -r f ". The light oil is close to the T2 of the water, so that the oil phase T2 can be directly used f And water phase r f Build T2 f -r f The relation type water phase T2 is firstly obtained without additionally carrying out gas flooding experiments according to a conventional method f . Wherein, T1: longitudinal relaxation time, T2: transverse relaxation time.
S7: and drawing a two-dimensional nuclear magnetism quantitative characterization plate of the crack.
S71: will T m Projection to T f And drawing a two-dimensional nuclear magnetic spectrum of the hole seam in the same coordinate system.
S72: at crack T2 f Place label r f Values.
S73: at the matrix pore T2 m Place label r m Values.
S8: and (5) ending.
The embodiment discloses a method for calibrating two-dimensional nuclear magnetic distribution of a carbonate light oil reservoir crack. In the embodiment, the full-diameter carbonate rock crack content is quantified by using the micron CT, calibration parameters are provided for two-dimensional nuclear magnetic testing of the crack, and the drawing plate is suitable for evaluating the crack development characteristics of the carbonate rock light oil reservoir. The method comprises the following steps: 1) Saturating the rock sample with the KI solution; 2) Calculating a total porosity; 3) CT scanning (KI-CTum) to quantify crack aperture and content; 4) Calculating two-dimensional nuclear magnetic distribution of the crack by a gas displacement experiment and a difference spectrum method; 6) And drawing a two-dimensional nuclear magnetic pattern plate of the crack.
Further, CT scanning is the basis of quantitative evaluation of cracks, in the embodiment, the content and the size of the cracks are calibrated through CT scanning technology, and then the distribution state of nuclear magnetism of the cracks is determined by combining gas-driven experiments. The existing method for distinguishing the matrix holes and the cracks by using the CT images is quite large, the embodiment adopts the existing artificial intelligent image processing technology to extract the matrix holes and the cracks, and the details of the hole-crack CT identification classification technology are not discussed deeply.
CT scanning is performed in a saturated potassium iodide solution rock sample, and is a key for accurately distinguishing shale matrix holes and cracks by utilizing nano CT. Potassium iodide (KI) has the effect of enhancing CT signals, and CT images can be lightened after potassium iodide solution is saturated in pores, so that CT differentiation of the pores, cracks and skeleton particles of a rock sample matrix is improved. While KI does not affect the NMR signal accuracy.
The conventional method is that the dry rock sample CT scanning extracts pore information, and the embodiment carries out CT scanning on a saturated potassium iodide sample, and has two advantages: 1) The massive development of cracks causes poor discrimination of the rock sample pore seams, and the saturated potassium iodide solution is more beneficial to distinguishing pores and seams. 2) The increase in CT signal intensity facilitates accurate extraction of the "matrix pore 2" under resolution-permitting conditions, thereby defining the "matrix pore 1" and "matrix pore 2" boundaries (fig. 1).
In the embodiment, the full-diameter sample is used for carrying out experiments instead of the traditional centimeter-level plunger, so that the problem of carbonate fracture loss caused by strong heterogeneity is solved. Meanwhile, due to the influence of the core size and the instrument resolution, CT can only identify holes and slits higher than the instrument resolution (about 30-50 um), so that a large number of matrix pores can be ignored, and the defect is corrected by calculating the porosity through a saturated weighing experiment in the embodiment.
The gas drive experiment is used for acquiring the physical boundary state of the matrix hole and the crack. The fracture belongs to a dominant seepage channel, gas can preferentially pass through the fracture, and therefore water in the fracture can be discharged out of the rock before the matrix pores. It typically takes more than 2 hours to complete a CT scan of a full diameter sample, and during this time period the gas drive experiment may have been completed but may also be out of specification, so a continuous CT cycle scan is impractical. The embodiment designs a critical state evaluation method, the crack content is quantified through CT scanning and weighing experiments of a saturated sample, water in the crack is driven out in the state, and residual fluid is matrix pore water.
In the embodiment, the pore gap is not directly distinguished by oil flooding, but a differential spectrum method is adopted, so that the problem of overlapping of the matrix pores and the microcracks is avoided.
The embodiment is mainly suitable for carbonate rock samples with larger-size cracks.
This example is applicable to light oil layers, but not medium-heavy oil layers.
In the embodiment, a full-diameter sample is used for carrying out experiments instead of a traditional centimeter-level plunger, the problem of crack loss caused by strong heterogeneity is solved, a crack two-dimensional nuclear magnetism T1-T2 distribution chart is drawn, the application blank of a two-dimensional nuclear magnetism technology in crack evaluation of a crack type carbonate rock light oil reservoir is filled, and the method has scientificity and universality.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims (10)
1. The method for calibrating the two-dimensional nuclear magnetic distribution of the carbonate light oil reservoir cracks is characterized by comprising the following steps of:
selecting a rock sample, and processing the rock sample based on a saturation method to obtain a saturated water rock sample and a saturated oil rock sample;
performing CT scanning experiments on the saturated water rock sample to obtain rock sample cracks, and converting CT scanning images of crack apertures into bar charts;
performing a gas displacement experiment on the saturated oil rock sample to obtain a gas displacement rock sample;
respectively carrying out two-dimensional nuclear magnetic scanning experiments on a saturated oil rock sample and a gas flooding rock sample, and then obtaining a crack two-dimensional nuclear magnetic T1-T2 spectrum based on a difference spectrum method;
calibrating a fracture aperture-time quantitative conversion relation based on the fracture two-dimensional nuclear magnetism T1-T2 spectrum and a histogram of the fracture aperture;
and obtaining the quantitative characterization distribution of the two-dimensional nuclear magnetism of the crack based on the quantitative conversion relation of the aperture and the time of the crack.
2. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 1, wherein the method comprises the steps of,
the process of selecting the rock sample comprises the following steps: and preparing a full-diameter sample with a preset size based on the crack development carbonate rock to obtain a rock sample.
3. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 1, wherein the method comprises the steps of,
the process of obtaining saturated water and saturated oil rock samples comprises: drying, weighing and measuring the volume of the rock sample to obtain a first mass and a total volume; selecting a part of dried rock sample, vacuumizing, and pressurizing a saturated potassium iodide solution for 24 hours to obtain a saturated water rock sample; and (5) vacuumizing the rest rock sample, and pressurizing saturated light oil for 24 hours to obtain a saturated oil rock sample.
4. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 3, wherein the method comprises the steps of,
the process of obtaining a rock sample fracture includes: performing CT scanning experiments on the saturated water rock sample to obtain a plurality of hole seams; and distinguishing the hole and the slit based on a digital image processing technology to obtain a matrix hole and a slit.
5. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 4, wherein the method comprises the steps of,
the process after obtaining the rock sample fracture further comprises: obtaining matrix pore porosities corresponding to the matrix pores, and performing difference on CT porosities and matrix pore porosities to obtain crack porosities; and obtaining the fracture volume based on the product of the fracture porosity and the total volume of the rock sample.
6. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 5, wherein the method comprises the steps of,
the process after performing the CT scan experiment further includes: and obtaining the mass of the saturated water rock sample as a second mass, obtaining the total porosity of the rock sample based on the first mass, the second mass, the total volume of the rock sample and the fluid density of the saturated water rock sample, and correcting the crack content based on the ratio of the crack porosity to the total porosity.
7. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 4, wherein the method comprises the steps of,
the process of carrying out the gas displacement experiment on the saturated oil rock sample comprises the following steps: placing a saturated oil rock sample into a clamp holder, then adding confining pressure for fixation, and injecting gas into the saturated oil rock sample; and placing a measuring cylinder at the outlet end of the clamp holder to collect liquid discharged from the hole, continuing the gas displacement experiment when the liquid output of the outlet end is smaller than the volume of the crack, and ending the gas displacement experiment when the liquid output of the outlet end is equal to the volume of the crack to obtain the gas displacement rock sample.
8. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 1, wherein the method comprises the steps of,
the process for obtaining the two-dimensional nuclear magnetism T1-T2 spectrum of the crack comprises the following steps: respectively carrying out two-dimensional nuclear magnetic scanning experiments on the saturated oil rock sample and the gas displacement rock sample to obtain a corresponding hole seam integral two-dimensional nuclear magnetic T1-T2 spectrum and a matrix hole two-dimensional nuclear magnetic T1-T2 spectrum; the integral two-dimensional nuclear magnetism T1-T2 spectrum of the hole seam and the two-dimensional nuclear magnetism T1-T2 spectrum of the matrix hole are subjected to difference to obtain a crack two-dimensional nuclear magnetism T1-T2 spectrum; the two-dimensional nuclear magnetism T1-T2 spectrum of the crack comprises a longitudinal relaxation spectrum of the crack in an oil-containing state and a transverse relaxation spectrum of the crack in the oil-containing state.
9. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 8, wherein the method comprises the steps of,
the process for calibrating the quantitative conversion relation between the aperture of the crack and the time comprises the following steps: pattern matching is carried out on a histogram based on the aperture of the crack and the transverse relaxation spectrum of the crack in the oil-containing state, and a plurality of crossing points are extracted; and establishing a quantitative conversion relation between the aperture of the crack and the time based on the plurality of crossing points.
10. The method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks according to claim 8, wherein the method comprises the steps of,
the process for obtaining the two-dimensional nuclear magnetism quantitative characterization distribution of the crack comprises the following steps: projecting the matrix pore two-dimensional nuclear magnetism T1-T2 spectrum to a coordinate system where the crack two-dimensional nuclear magnetism T1-T2 spectrum is located, drawing a pore two-dimensional nuclear magnetism spectrum under the same coordinate system, marking a crack aperture value at a crack in the pore two-dimensional nuclear magnetism spectrum, and marking a matrix pore aperture value at a matrix pore to obtain quantitative characterization distribution of the crack two-dimensional nuclear magnetism.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311203460.XA CN116953012B (en) | 2023-09-19 | 2023-09-19 | Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311203460.XA CN116953012B (en) | 2023-09-19 | 2023-09-19 | Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116953012A true CN116953012A (en) | 2023-10-27 |
| CN116953012B CN116953012B (en) | 2023-11-24 |
Family
ID=88454859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311203460.XA Active CN116953012B (en) | 2023-09-19 | 2023-09-19 | Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116953012B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117233064A (en) * | 2023-11-16 | 2023-12-15 | 东北石油大学三亚海洋油气研究院 | Method for calculating shale nuclear magnetic resonance logging fracture cut-off value |
| CN117269223A (en) * | 2023-11-20 | 2023-12-22 | 东北石油大学三亚海洋油气研究院 | Method for calibrating multi-scale crack two-dimensional nuclear magnetism T1-T2 distribution of lamellar shale |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020175682A1 (en) * | 2001-05-23 | 2002-11-28 | Songhua Chen | Rapid nmr multi-frequency t1 and t2 acquisition for earth formations evaluation with mwd or wireline tools |
| US20130057277A1 (en) * | 2010-01-22 | 2013-03-07 | Lukasz Zielinski | Method for Determining Rock Formation Fluid Interaction Properties Using Nuclear Magnetic Resonance Well Logging Measurements |
| CN113189129A (en) * | 2021-05-07 | 2021-07-30 | 中国石油天然气股份有限公司 | Rock crack porosity detection process |
| CN114412429A (en) * | 2022-01-20 | 2022-04-29 | 中国地质大学（武汉） | Method for testing relation between crack size of Brazilian splitting method and nuclear magnetism T2 |
| CN114486976A (en) * | 2022-01-20 | 2022-05-13 | 东北石油大学 | Method for measuring crack distribution of Brazilian splitting method based on nuclear magnetic resonance |
-
2023
- 2023-09-19 CN CN202311203460.XA patent/CN116953012B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020175682A1 (en) * | 2001-05-23 | 2002-11-28 | Songhua Chen | Rapid nmr multi-frequency t1 and t2 acquisition for earth formations evaluation with mwd or wireline tools |
| US20130057277A1 (en) * | 2010-01-22 | 2013-03-07 | Lukasz Zielinski | Method for Determining Rock Formation Fluid Interaction Properties Using Nuclear Magnetic Resonance Well Logging Measurements |
| CN113189129A (en) * | 2021-05-07 | 2021-07-30 | 中国石油天然气股份有限公司 | Rock crack porosity detection process |
| CN114412429A (en) * | 2022-01-20 | 2022-04-29 | 中国地质大学（武汉） | Method for testing relation between crack size of Brazilian splitting method and nuclear magnetism T2 |
| CN114486976A (en) * | 2022-01-20 | 2022-05-13 | 东北石油大学 | Method for measuring crack distribution of Brazilian splitting method based on nuclear magnetic resonance |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117233064A (en) * | 2023-11-16 | 2023-12-15 | 东北石油大学三亚海洋油气研究院 | Method for calculating shale nuclear magnetic resonance logging fracture cut-off value |
| CN117233064B (en) * | 2023-11-16 | 2024-01-30 | 东北石油大学三亚海洋油气研究院 | Method for calculating shale nuclear magnetic resonance logging fracture cut-off value |
| CN117269223A (en) * | 2023-11-20 | 2023-12-22 | 东北石油大学三亚海洋油气研究院 | Method for calibrating multi-scale crack two-dimensional nuclear magnetism T1-T2 distribution of lamellar shale |
| CN117269223B (en) * | 2023-11-20 | 2024-01-26 | 东北石油大学三亚海洋油气研究院 | Method for calibrating multi-scale crack two-dimensional nuclear magnetism T1-T2 distribution of lamellar shale |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116953012B (en) | 2023-11-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN116953012B (en) | Method for calibrating two-dimensional nuclear magnetic distribution of carbonate light oil reservoir cracks | |
| CN116930244B (en) | Nuclear magnetism graphic plate drawing method for thick oil cracks | |
| US10161891B1 (en) | Method for characterizing rock physical characteristics of deeply buried carbonate rocks | |
| CN109060623B (en) | Compact sandstone pore size distribution joint characterization method | |
| CN104819923B (en) | Low permeability sandstone reservoir pore structure quantitative inversion method based on nuclear magnetic resonance | |
| CN108627533A (en) | Fluid employs the nuclear magnetic resonance experiment method and device of feature in a kind of measurement porous media | |
| CN106018740B (en) | Hole pressure touching methods demarcate can system | |
| CN106896047B (en) | A kind of experimental rig and method of simultaneous determination soil water feature and infiltration linearity curve | |
| CN110021030A (en) | A kind of segmentation threshold of material of rock and soil digital picture determines method | |
| CN101672761A (en) | Device and method for testing soil-water characteristic curve of sandy soil | |
| CN110441142A (en) | A kind of method of Digital image technology measurement three axis specimen surface membrane penetration of sandy gravel | |
| CN110927035A (en) | Method for calculating saturation of irreducible tight sandstone bound water | |
| CN104155427A (en) | Low back pressure saturation method for loess liquidation experiment | |
| CN114412429B (en) | Method for testing relationship between crack size and nuclear magnetic T2 of Brazilian splitting method | |
| CN106777515B (en) | Method for analyzing production energy of tight gas well based on rock core experiment data | |
| CN107101773A (en) | Method and device for testing bubble point pressure value and quasi-bubble point pressure value | |
| CN108343095A (en) | The experimental rig and method of static pressure pile-sinking in the simulation saturation soil body | |
| CN105807007B (en) | A kind of drill core test system and detection method | |
| CN208187733U (en) | A kind of artificial multistage drawing out soil equipment | |
| CN114624163A (en) | Overburden pressure pore-permeability test-based muddiness zeolite clastic rock reservoir physical property correction method | |
| CN111693427B (en) | Analysis method for mobility of oil and gas reservoir fluid | |
| CN113405962B (en) | Storage space evaluation method and device for carbonate reservoir | |
| CN117269223B (en) | Method for calibrating multi-scale crack two-dimensional nuclear magnetism T1-T2 distribution of lamellar shale | |
| CN115876659A (en) | Method and system for obtaining shale pore and fracture volume | |
| CN205720159U (en) | A kind of drill core test system |
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 |