CN111006985B - Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions - Google Patents
Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions Download PDFInfo
- Publication number
- CN111006985B CN111006985B CN201911093659.5A CN201911093659A CN111006985B CN 111006985 B CN111006985 B CN 111006985B CN 201911093659 A CN201911093659 A CN 201911093659A CN 111006985 B CN111006985 B CN 111006985B
- Authority
- CN
- China
- Prior art keywords
- reservoir
- measured
- pressure
- saturated water
- porosity
- 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.)
- Active
Links
- 239000011148 porous material Substances 0.000 title claims abstract description 97
- 238000000034 method Methods 0.000 title claims abstract description 63
- 238000011158 quantitative evaluation Methods 0.000 title claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 65
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 64
- 238000009826 distribution Methods 0.000 claims abstract description 45
- 238000001228 spectrum Methods 0.000 claims abstract description 44
- 239000011435 rock Substances 0.000 claims abstract description 38
- 238000005481 NMR spectroscopy Methods 0.000 claims abstract description 35
- 230000015572 biosynthetic process Effects 0.000 claims description 17
- 238000012512 characterization method Methods 0.000 claims description 7
- 238000004088 simulation Methods 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 4
- 238000009933 burial Methods 0.000 abstract description 2
- 239000003921 oil Substances 0.000 description 23
- 238000005516 engineering process Methods 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 238000011161 development Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 239000003079 shale oil Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000009825 accumulation Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 235000011850 desserts Nutrition 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 241000234314 Zingiber Species 0.000 description 1
- 235000006886 Zingiber officinale Nutrition 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 235000008397 ginger Nutrition 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000000235 small-angle X-ray scattering Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/088—Investigating volume, surface area, size or distribution of pores; Porosimetry
-
- 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
-
- 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
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Pathology (AREA)
- Immunology (AREA)
- High Energy & Nuclear Physics (AREA)
- Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Dispersion Chemistry (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention provides a quantitative evaluation method for pore throat effectiveness of a dense reservoir of a land lake basin under geological conditions. The method comprises the following steps: establishing a relation between nuclear magnetic resonance signal intensity and porosity; t of reservoir rock core to be measured after saturated water measurement under normal pressure environment 2 A spectrum; applying confining pressures of different pressure values to reservoir cores to be measured after saturated water sequentially to simulate pressure-bearing change conditions of rock pore structures in stratum burial process, and respectively measuring T of the reservoir cores to be measured after saturated water under confining pressures of different pressure values 2 A spectrum; measured T 2 And determining pore diameter-porosity distribution of the rock core of the reservoir to be measured under different pressure values by combining the established relation between nuclear magnetic resonance signal intensity and porosity, and quantitatively evaluating the change of the effective pore throats of different scales of the tight reservoir under geological conditions, thereby realizing quantitative evaluation of the effectiveness of the pore throats of different scales of the tight reservoir of the land-phase lake basin under geological conditions.
Description
Technical Field
The invention relates to an evaluation method of oil content of a dense reservoir of a land lake basin, in particular to a method for quantitatively evaluating oil content of communicated and non-communicated pores of the dense reservoir.
Background
In recent years, dense (shale) oil resources are becoming increasingly hot spots for global oil production in increased reservoirs as successor resources for conventional oil fields. The dense oil reservoir develops a nano-micron multi-scale complex pore throat system (Zhengle, zhu Rukai, bai, etc. nano pore throats in national oil and gas reservoirs were first discovered and have scientific value [ J ]. Rock theory, 2011,27 (6): 857-1864). Compared with the conventional oil gas which pays attention to the matching relation of six elements, the microscopic pore throat structure characteristics of the reservoir body are subjected to fine research and quantitative evaluation, and are key to the exploration and development of compact oil resources. Microcosmic pore throat structure characteristics including pore and throat geometry, size, distribution and their interconnection relationship (Wu Sheng and, qihua. Gas reservoir geology [ M ]. Beijing: oil industry Press 1998: 20-65), are the basis for establishing unconventional oil and gas reservoir evaluation criteria, revealing compact oil and gas formation factors, reservoir properties, enrichment rules. Deep knowledge of the microcosmic pore throat characteristics and quantitative evaluation structure of tight reservoirs is significant for efficient utilization of tight (shale) oil resources.
The dense oil reservoir in China is characterized by land phase deposition, relatively small distribution area, poor physical properties, strong micro-nano level and heterogeneous nature of pores (Du Jinhu, liu Ge, ma Desheng, etc.. The technology for effectively developing dense oil in China is tried to be [ J ]. Oil exploration and development, 2014,41 (2): 198-205; yang Zhifeng, zeng Jianhui, feng Xiao, etc.. Dense sandstone reservoir is characterized by small-scale heterogeneous nature and oil enrichment [ J ],2016,45 (1): 119-127), and the technology for researching pore structure of conventional oil and gas reservoirs such as flake identification, image analysis, mercury intrusion method, casting body analysis method, etc. is difficult to realize precise characterization of nano level pore throat structure system. The scholars at home and abroad actively explore the microcosmic pore throat characterization technology of a compact (shale) reservoir, and a plurality of test methods such as constant-speed mercury-pressing, maps imaging analysis technology, digital core technology and the like are formed. The method forms high-resolution observation technologies such as argon ion polishing sample preparation equipment, field emission scanning electron microscope image observation, small-angle X-ray scattering and the like in aspects of pore-throat morphology, size and distribution analysis, and test technologies such as high-pressure mercury compression, constant-speed mercury compression, nuclear magnetic resonance, gas adsorption and the like, and obtains information such as pore-throat morphology, pore-diameter distribution and the like of different levels of samples (Bai, zhu Rukai, wu Songtao and the like. In the aspect of crude oil occurrence state research, the adsorption and free state (the wrinkling can be judged, yang Zhi, cui Jingwei, etc.) of organic matters are mainly judged by combining field emission, an environmental scanning electron microscope and energy spectrum analysis, the shale oil formation mechanism, geological characteristics and development countermeasures [ J ]. Petroleum exploration and development, 2013,40 (1): 14-26). The method mainly adopts the methods of laser scanning confocal reconstruction three-dimensional image method, three-dimensional nano imaging CT, focused ion beam imaging technology and the like in the aspects of Kong Hou morphology and connectivity.
The multi-method and multi-scale matching technology effectively improves the characterization precision of the micro pore throat structure of the compact (shale) reservoir, but has some problems in actually describing the micro pore throat structure characteristics of compact (shale) oil. For example, different methods differ in terms of test principle, test range and accuracy; sample handling and experimental procedures can destroy the original pore structure; the pore-throat characteristics experiments mostly do not consider the actual temperature-pressure conditions of the subsurface, etc. There have been many studies showing that the variation of temperature and pressure conditions during sedimentary, diagenetic and mature evolution and the like affects and reforms the pore throat structure characteristics of the reservoir (ginger in the heart, zhang Wenzhao, liang Chaodeng. Shale oil reservoir basic characteristics and evaluation factors [ J ]. Petroleum report, 2014,35 (1): 184-196; cui Jingwei, zhu Rukai, cui Jinggang. Shale pore evolution and relation thereof to residual hydrocarbon content: evidence from simulation experiments under geological process constraints [ J ]. Geological report, 2013,87 (5): 730-736; zhang Lin, bao Youshu, liyuan and the like. Lake shale oil mobility is exemplified by the depression of the Bay of Bohai basin in the east of the heart [ J ]. Petroleum exploration and development 2014,41 (6): 641-649), the analysis and determination performed by only changing the filling pressure without considering the temperature and pressure conditions cannot satisfy the accurate evaluation of the true microcosmic pore throat structure of the compact (shale).
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide the quantitative evaluation method for the effectiveness of the pore throats of the tight reservoir, which can realize quantitative characterization of dynamic change of microscopic pore throats of the tight reservoir under a geological background.
In order to achieve the above object, the invention provides a quantitative evaluation method for the effectiveness of a dense reservoir pore throat of a land lake basin under geological conditions, wherein the method comprises the following steps:
1) Establishing a relation between nuclear magnetic resonance signal intensity and porosity;
2) Measuring a T2 spectrum of a reservoir rock core to be measured after saturated water under the environment of normal temperature and normal pressure; the method is used for representing the condition of the effective pore structure of the reservoir core to be tested;
3) Applying confining pressures of different pressure values to reservoir cores to be measured after saturated water in sequence, wherein the reservoir cores to be measured are at corresponding stratum temperatures when the confining pressures are applied, so as to simulate the pressure-bearing change condition of rock pore structures at the corresponding stratum temperatures in the stratum burying process, and respectively measuring T of the reservoir cores to be measured after saturated water under the confining pressures of different pressure values 2 A spectrum; the method is used for representing the condition of an effective pore structure of the reservoir core to be tested under confining pressures of different pressure values;
4) T determined according to step 2), step 3) 2 The spectrum, combining the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1), determines the pore diameter-porosity distribution of the reservoir rock core to be measured under different pressure values, namely the porosity distribution of pore throats with different diameters;
5) According to the pore diameter-porosity distribution of the rock core of the reservoir to be measured under different pressure values determined in the step 4), quantitative evaluation is carried out on the change of the effective pore throats of the different scales of the tight reservoir along with the pressure change, namely the change of the effective pore throats of the different scales of the tight reservoir under geological conditions, so that quantitative evaluation of the effectiveness of the pore throats of the different scales of the tight reservoir of the land-phase lake basin under geological conditions is realized.
In the quantitative evaluation method, the internal effective pore structure, namely the internal communicated pore structure, can be effectively represented after the reservoir core to be measured is treated with saturated water.
In the quantitative evaluation method, confining pressures with different pressure values are sequentially applied to the reservoir core to be measured after saturated water, so that the change condition of the rock pore structure in the bearing process of stratum burial can be effectively simulated.
In the above quantitative evaluation method, preferably, step 1) is realized by: and (3) calibrating the porosity of the tight reservoir and the nuclear magnetic resonance signal by using a standard scale sample, so that a relation between the intensity of the nuclear magnetic resonance signal and the porosity is established. In a preferred embodiment, the relationship between nuclear magnetic resonance signal intensity and porosity is:
wherein phi is the porosity of the standard scale sample,
for the porosity of the reservoir core to be tested, NS is the accumulation times of standard scale samples, NS is the accumulation times of the samples to be tested, RG1 and RG2 are respectively the analog gain (RG 1 for short) and the digital gain (RG 2 for short) of the standard scale samples, RG1 and RG2 are respectively the analog gain (RG 1 for short) and the digital gain (RG 2 for short) of the reservoir core to be tested, S is the nuclear magnetic signal strength value of the standard scale samples, and S is the nuclear magnetic signal strength value of the reservoir core to be tested; and (3) performing linear fitting on the porosity and the nuclear magnetic resonance signal intensity of the standard scale sample based on the formula, and determining a relation between the nuclear magnetic resonance signal intensity and the porosity.
In the above quantitative evaluation method, preferably, the reservoir core to be measured after saturation is obtained by performing vacuum pressurization saturated water treatment on the reservoir core to be measured; wherein, the time of vacuumizing is preferably 8 hours, the pressure of the pressurized saturated water is preferably 15Mpa, and the time of pressurizing the saturated water is preferably 12 hours.
In the above quantitative evaluation method, preferably, the method further comprises: t of reservoir core to be measured after saturated water measured in step 2), step 3) 2 The spectrum is combined with the relation established in the step 1), and the porosity of the reservoir rock core to be measured under different pressures is calculated; and quantitatively evaluating the change of the porosity of the tight reservoir under geological conditions.
In the above quantitative evaluation method, preferably, in step 3), the confining pressure of different pressure values is applied to the reservoir core to be measured after saturated water sequentially, and the confining pressure is applied by using an external simulation gripper.
In the above quantitative evaluation method, it is preferable that the step 3) of sequentially applying the confining pressures of different pressure values is performed by sequentially applying confining pressures of small to large pressure values.
In the quantitative evaluation method, the confining pressure value can be determined according to the actual stratum condition of the region where the reservoir core to be measured is located, the pressure value corresponding to the geologic age where the reservoir core to be measured is located can be generally calculated according to the pressure gradients of different basins, and the depth calculation corresponding to the research significance is selected as the confining pressure value; for example, the corresponding pressure value calculated by combining the depth corresponding to the critical reservoir period and the formation pressure gradient can be selected as the confining pressure value (formation pressure gradient x formation depth = pressure value of the formation at the depth); for example, the formation pressure gradient can be determined according to the formation depth in the reservoir evolution process to be measured; for example, 3MPa, 6MPa, 9MPa, 12MPa.
In the above quantitative evaluation method, preferably, in step 3), the corresponding formation temperature is a formation temperature corresponding to a confining pressure value, and the temperature is determined by a formation depth corresponding to a ground temperature gradient combined with the confining pressure value (the temperature=ground surface temperature+ground temperature gradient×formation depth). The different confining pressure values and the corresponding temperatures can be used for simulating the pressure of the reservoir core to be tested in different geological periods and the temperature of the stratum.
In the above quantitative evaluation method, preferably, the confining pressure value is not higher than the rock breaking pressure.
In the above quantitative evaluation method, preferably, step 3) the applying process of applying confining pressures with different pressure values to the reservoir core to be measured after saturated water sequentially includes a pressure increasing process and a pressure maintaining process; at the moment, T of the reservoir rock core to be measured under different confining pressures after the step 3) is described and respectively measured on saturated water 2 The spectrum is specifically T of a reservoir rock core to be measured after saturated water after pressure maintaining of each confining pressure value is measured 2 A spectrum; for example, the pressurization may be achieved by applying the pressure for 1h and the holding pressure for 1h to complete the application of the confining pressure. This manner of applying confining pressure helps to adequately simulate different pressure environments.
In the above quantitative evaluation method, preferably, step 3) further includes determining T of the reservoir core to be measured after saturated water for different holding time periods when the reservoir core to be measured after saturated water is held under different confining pressures 2 A spectrum. In a specific embodiment, a certain confining pressure is applied to the reservoir core to be measured after saturated water and the reservoir core to be measured is maintained for a period of time, and the T of the reservoir core to be measured after saturated water with different pressure maintaining time durations is measured 2 A spectrum; then repeating the process under the next confining pressure value until the measurement under all confining pressure values is completed; determination of T for different dwell times 2 Spectrum avoiding adverse effects due to hysteresis effects of applied confining pressure in experiments, determination of T at different dwell times 2 And the spectrum is used for observing whether the pore changes are consistent or not, so that the influence caused by confining pressure is reflected more truly.
In the above quantitative evaluation method, preferably, T is measured according to step 2) or step 3) 2 The specific implementation manner of determining the pore diameter-porosity distribution of the reservoir rock core to be measured under different pressure values, namely the porosity distribution of pore throats with different diameters by combining the spectrum and the relational expression established in the step 1) comprises the following steps:
A. t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3) 2 Distribution of nuclear magnetic signal intensity of spectrum and T of reservoir rock core to be measured under normal pressure after saturated water measured in step 2) 2 Calculating the porosity distribution characteristics of the reservoir core to be measured under different pressure conditions after saturated water according to the nuclear magnetic resonance signal intensity distribution of the spectrum and the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1);
B. calculating pore throat diameter distribution under different pressure conditions, namely core magnetic signal intensity distribution of pore throats with different diameters under different pressure conditions, based on the T2 spectrum of the reservoir core to be measured under different surrounding pressures after saturated water is measured according to the step 3) and the T2 spectrum of the reservoir core to be measured under normal pressure after saturated water is measured according to the step 2);
C. and combining the A and the B to obtain pore diameter-porosity distribution of the reservoir rock core to be measured under different pressures.
In a specific embodiment, the quantitative evaluation method for the effectiveness of the dense pore throats of the land lake basin under the geological condition provided by the invention comprises the following steps:
step 1: calibrating the porosity of the tight reservoir and the nuclear magnetic resonance signal by using a standard scale sample, and establishing a relation between the intensity of the nuclear magnetic resonance signal and the porosity;
step 2: saturated water treatment is carried out on the reservoir rock core to be measured under normal pressure, specifically, a vacuum pressurizing saturation device is adopted for saturationWater treatment, evacuation time is 8 hours, pressure is 15MPa, and saturation time is 12 hours; then determining the T of the core of the reservoir to be measured after saturated water at normal temperature and normal pressure 2 A spectrum; according to the T of the measured reservoir core after saturated water under normal pressure 2 Calculating the porosity of the reservoir core to be measured under normal pressure by combining the spectrum with the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1;
step 3: sequentially applying small to large confining pressures to the reservoir core to be measured after saturated water by using an external simulation clamp holder, wherein the confining pressures are 3MPa, 6MPa, 9MPa and 12MPa in sequence; when each pressure value is applied, the pressure is continuously applied for 1h, the pressure is maintained for 1h, and when each pressure value is applied, the core of the reservoir to be tested is at a corresponding temperature (the temperature is the stratum temperature corresponding to the confining pressure value and is determined by the ground temperature gradient combined with the stratum depth corresponding to the confining pressure value); and respectively measuring T of the reservoir rock core to be measured under different confining pressures after saturated water 2 A spectrum; according to the measured T of the reservoir rock core to be measured under different confining pressures 2 Determining the porosity of the reservoir core to be tested under different confining pressures by combining the spectrum with the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1;
step 4: t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3 2 Distribution of nuclear magnetic signal intensity of spectrum and T of reservoir rock core to be measured under normal pressure after saturated water measured in step 2 2 Calculating the porosity distribution characteristics of the reservoir core to be measured under different pressure conditions after saturated water by combining the nuclear magnetic resonance signal intensity distribution of the spectrum and the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1;
step 5: t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3 2 Spectrum and T of reservoir core to be measured after saturated water under normal pressure measured in step 2 2 Spectrum calculation is carried out on pore throat diameter distribution under different pressure conditions, namely, nuclear magnetic signal intensity distribution of pore throats with different diameters under different pressure conditions;
step 6: obtaining pore diameter-porosity distribution of the reservoir core to be measured after saturated water under different pressures by the porosity distribution characteristics under different pressure conditions determined in the step 4 and the nuclear magnetic signal intensity distribution of pore throats with different diameters determined in the step 5; based on pore diameter-porosity distribution of reservoir cores to be measured after saturated water under different pressures, quantitative evaluation of the change of effective pore throats of different scales of a tight reservoir along with pressure changes (namely, the change of the effective pore throats of different scales of the tight reservoir under geological conditions) and the change of effective porosity of the tight reservoir along with the pressure changes (namely, the change of the effective porosity of the tight reservoir under geological conditions) is carried out, so that quantitative evaluation of the effectiveness of the pore throats of different scales of the tight reservoir of a land-phase lake basin under geological conditions is realized.
Aiming at a tight reservoir, microscopic pore-throat structure evaluation under the constraint of a temperature-pressure geological process under a real geological condition is carried out, and a set of accurate evaluation method for the multi-scale pore-throat structure characteristics of a land-phase tight (shale) oil reservoir is established. The evaluation method provided by the invention is based on simulating the porosity of the tight reservoir (shale) under different pressure conditions, realizes quantitative measurement of pore change characteristics of the sample reservoir under the simulated different formation pressure conditions by applying confining pressure, finally fits and establishes pore change curves of pore throats with different diameters under different pressure conditions, quantitatively predicts the change rule of the tight reservoir (shale) reservoir performance under geological background (namely the change condition of the porosity under different pressure conditions), and provides parameters for evaluation and prediction of land shale (tight) oil desserts.
The invention provides a quantitative evaluation method for microscopic pore throat change under the constraint of different temperature and pressure geological processes based on a real geological background aiming at a land-phase tight reservoir (including shale oil reservoir), which accurately and quantitatively evaluates pore throat effective change conditions in the change process of the land-phase tight reservoir along with geological evolution. Compared with the prior art, the invention has the following advantages:
1. the technical scheme provided by the invention realizes the simulation of dynamic evolution of microscopic pore throats; the method and the device have the advantages that the microstructure of the compact reservoir is an important parameter for evaluating desserts, is an important characteristic for revealing the formation condition and the enrichment rule of compact oil, only focuses on the current surface characteristics of the microstructure of the compact reservoir, but correspondingly changes the microstructure along with geological evolution, and the quantitative characterization of the dynamic change of the microstructure of the compact reservoir is realized by the technical scheme provided by the invention.
2. The technical scheme provided by the invention realizes accurate characterization of microcosmic pore throats with different scales; the diameter distribution range of the micro pore throats of the tight reservoir is large, and from a few nanometers to a few micrometers, the tight reservoir storage space is formed.
Drawings
FIG. 1 is a flow chart of a method for quantitatively evaluating the oil content of unconnected pores of a dense reservoir of a land lake basin.
FIG. 2 is a graph of sample porosity calibration for example 1.
FIG. 3A shows the relaxation time T2 spectra of samples at different pressures (0 MPa, 3MPa, 6MPa, 9 MPa) of example 1.
FIG. 3B is a sample relaxation time T2 spectrum at 12MPa of example 1.
FIG. 4A is a graph showing the magnetic signal change of mesoporous laryngeal core of the sample at different pressures (0 Mpa, 3Mpa, 6Mpa, 9 Mpa) in example 1.
FIG. 4B is a graph showing the change of mesoporous laryngeal nuclear magnetic signals of the sample at 12MPa in example 1.
FIG. 5A is a graph showing the variation of the nuclear magnetic resonance signal of a macro Kong Konghou sample of example 1 at different pressures (0 MPa, 3MPa, 6MPa, 9 MPa).
FIG. 5B is a graph showing the change of nuclear magnetic resonance signal of a sample macro Kong Konghou under 12MPa in example 1.
FIG. 6 is a graph of pore size versus porosity for samples at various pressures of example 1.
FIG. 7 is a graph showing the relative change in pore throat porosity at various pressures for samples of example 1.
Detailed Description
The technical solution of the present invention will be described in detail below for a clearer understanding of technical features, objects and advantageous effects of the present invention, but should not be construed as limiting the scope of the present invention.
Example 1
The embodiment provides a quantitative evaluation method for the pore throat effectiveness of a dense reservoir of a land lake basin (see fig. 1), wherein the method comprises the following steps:
step 1: calibrating the porosity of the tight reservoir and the nuclear magnetic resonance signal by using a standard scale sample, and establishing a relation between the intensity of the nuclear magnetic resonance signal and the porosity;
specifically, the relationship between nuclear magnetic resonance signal intensity and porosity is:
wherein phi is the porosity of the standard scale sample,
for the porosity of the reservoir core to be measured, NS is the accumulation times of standard scale samples to be measured, RG1 and RG2 are the analog gain and the digital gain of the standard scale samples respectively, RG1 and RG2 are the analog gain and the digital gain of the reservoir core to be measured respectively, S is the nuclear magnetic signal strength value of the standard scale samples, and S is the nuclear magnetic signal strength value of the reservoir core to be measured; performing linear fitting on the porosity and the nuclear magnetic resonance signal intensity of the standard scale sample based on the formula, and determining a relation between the nuclear magnetic resonance signal intensity and the porosity, wherein y=360.72x+123.06 is shown in fig. 2; x is the porosity and y is the nuclear magnetic resonance signal intensity;
step 2: saturated water treatment is carried out on a reservoir rock core to be measured under normal pressure, specifically, a vacuum pressurizing saturation device is adopted for saturated water treatment, the vacuumizing time is 8 hours, the pressure is 15MPa, and the saturation time is 12 hours (core data refer to Table 1); then determining the T of the core of the reservoir to be measured after saturated water at normal temperature and normal pressure 2 A spectrum; according to the T of the measured reservoir core after saturated water under normal pressure 2 Calculating the porosity of the reservoir core to be measured under normal pressure by combining the spectrum with the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1;
TABLE 1 sample porosity values under saturated Water conditions at Normal temperature and pressure
| Original quality (g) | Saturation mass (g) | Density (g/cm) 3 ) | Volume (cm) 3 ) | Nuclear magnetic porosity (%) |
| 54.1452 | 55.1094 | 2.52 | 21.87 | 5.42 |
Step 3: sequentially applying small to large confining pressures to the reservoir core to be measured after saturated water by using an external simulation clamp holder, wherein the confining pressure values are sequentially 3MPa, 6MPa, 9MPa and 12MPa (the confining pressure values are obtained by calculating the depth corresponding to the critical reservoir period by combining with the formation pressure gradient, wherein the pressure gradient is 0.88MPa/100m, and the ground temperature gradient is 2.5 ℃/100 m); when each pressure value is applied, the pressure is continuously applied for 1h, the pressure is maintained for 3 h and 15 h, and the reservoir core to be measured is at the corresponding temperature when the confining pressure is applied (see table 2 in detail); t of reservoir rock core to be measured under different confining pressures after respectively measuring saturated water 2 Spectrum (measured T) 2 The spectra are shown in FIG. 3A-FIG. 3B, and only 12MPa has porosity variation at different times of pressure maintaining, and T at different pressure maintaining times under 3MPa, 6MPa and 9MPa 2 Overlapping the spectral curves); rock for determining reservoir rock core to be measuredThe rupture pressure P is near, and each applied confining pressure value does not exceed P Temporary face (L) The method comprises the steps of carrying out a first treatment on the surface of the Based on the measured T under different ambient pressures 2 Calculating the porosity of the reservoir core to be measured under normal pressure according to the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1, wherein the corresponding porosities of 3MPa, 6MPa, 9MPa and 12MPa are respectively 7.10%, 5.36%, 5.43% and 5.42%;
TABLE 2 values of confining pressure and corresponding temperatures
| Depth (m) | 300 | 700 | 1022 | 1500 |
| Confining pressure (Mpa) | 3 | 6 | 9 | 12 |
| Temperature (. Degree. C.) | 7.5 | 18 | 25 | 38 |
Step 4: t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3 2 Spectrum and saturated water under normal pressure measured in step 2T of later reservoir core to be measured 2 Calculating a porosity distribution characteristic diagram under different pressure conditions by combining nuclear magnetic resonance signal intensity distribution in a spectrum with the relation between nuclear magnetic resonance signal intensity and porosity established in the step 1;
t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3 2 Spectrum and T of reservoir core to be measured after saturated water under normal pressure measured in step 2 2 Spectrum calculation of pore throat diameter distribution under different pressure conditions, namely nuclear magnetic signal intensity distribution of pore throats with different diameters under different pressure conditions (shown in figures 4A-4B and 5A-5B);
step 5: obtaining the pore diameter-pore diameter distribution (the pore diameter distribution of pore throats with different diameters as shown in figure 6) corresponding to the pore diameter-pore diameter distribution characteristic of the reservoir rock core actual measurement after saturated water with different pressures according to the pore diameter distribution characteristic under different pressure conditions determined in the step 4 and the nuclear magnetic signal intensity distribution of the pore throats with different diameters; based on the porosity values corresponding to the measured pore diameter distribution characteristics of the reservoir rock cores to be measured after saturated water under different pressures, the effectiveness of pore throats of different scales of the tight reservoir (see table 3 and fig. 7 in detail) is quantitatively evaluated along with the pressure change, so that the quantitative evaluation of the effectiveness of the pore throats of different scales of the tight reservoir of the land-phase lake basin is realized.
TABLE 3 pore throat variation characteristics for samples of different dimensions under different pressure conditions
| Project | 0MPa | 3MPa | 6MPa | 9MPa | 12MPa | 12MPa-3h | 12MPa-15h |
| Mesoporous signal amplitude | 56746.10 | 56679.98 | 54732.25 | 54607.54 | 54568.41 | 53343.96 | 52660.79 |
| Macro-pore signal amplitude | 10332.42 | 10377.14 | 10584.35 | 10740.21 | 10843.64 | 10775.71 | 10768.63 |
| Relative change in |
0％ | -0.12％ | -3.55％ | -3.77％ | -3.84％ | -6.00％ | -7.20％ |
| Macropore volume |
0％ | 0.43％ | 2.44％ | 3.95％ | 4.95％ | 4.29％ | 4.22％ |
The mesopores are pores with the pore diameter of 2-50nm, and the macropores are pores with the pore diameter of more than 50 nm.
According to the test data (shown in table 3) under different confining pressures, the core of the reservoir to be tested does not change obviously under the condition of being lower than 3MPa after confining pressure is applied, and relatively larger change occurs when the pressure is gradually increased to a certain pressure (about 6 MPa). The mesoporous gradually reduces along with the increase of confining pressure, and the later stage is gradually gentle. The macro-pores gradually increase along with the pressure increase, and the later stage is also gradually gentle.
Claims (7)
1. A quantitative evaluation method for the pore throat effectiveness of a dense reservoir of a land-phase lake basin under geological conditions for realizing quantitative characterization of dynamic change of microscopic pore throats of the dense reservoir under geological background, wherein the method comprises the following steps:
1) Establishing a relation between nuclear magnetic resonance signal intensity and porosity;
2) T of reservoir core to be measured after measuring saturated water under normal temperature and normal pressure environment 2 A spectrum;
3) Applying confining pressures of different pressure values to reservoir cores to be measured after saturated water in sequence, wherein the reservoir cores to be measured are at corresponding stratum temperatures when the confining pressures are applied, so as to simulate the pressure-bearing change condition of rock pore structures at the corresponding stratum temperatures in the stratum burying process, and respectively measuring T of the reservoir cores to be measured after saturated water under the confining pressures of different pressure values 2 A spectrum; the pressure value of the confining pressure is determined by calculating the corresponding pressure value through the depth corresponding to the key reservoir period of the reservoir to be measured and the formation pressure gradient; wherein the corresponding formation temperatureThe temperature is the stratum temperature corresponding to the confining pressure value, and is determined by combining the ground temperature gradient with the stratum depth corresponding to the confining pressure value; wherein, the process of applying the confining pressure to the reservoir core to be measured after saturated water sequentially comprises a boosting process and a pressure maintaining process, and when the reservoir core to be measured after saturated water is subjected to pressure maintaining under different confining pressures, the T of the reservoir core to be measured after saturated water with different pressure maintaining time periods is measured 2 A spectrum;
4) T determined according to step 2), step 3) 2 Determining pore diameter-porosity distribution of the reservoir rock core to be measured under different pressure values, namely the porosity distribution of pore throats with different diameters by combining the spectrum and the relational expression established in the step 1);
the implementation manner of the step 4) comprises the following steps:
A. t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3) 2 Distribution of nuclear magnetic signal intensity of spectrum and T of reservoir rock core to be measured under normal pressure after saturated water measured in step 2) 2 Calculating the porosity distribution characteristics of the reservoir core to be measured under different pressure conditions after saturated water according to the nuclear magnetic resonance signal intensity distribution of the spectrum and the relation between the nuclear magnetic resonance signal intensity and the porosity established in the step 1);
B. t of reservoir rock core to be measured under different confining pressures after saturated water measured according to step 3) 2 Spectrum and T of reservoir core to be measured under normal pressure after saturated water measured in step 2) 2 Spectrum calculation is carried out on pore throat diameter distribution under different pressure conditions, namely, nuclear magnetic signal intensity distribution of pore throats with different diameters under different pressure conditions;
C. combining A and B to obtain pore diameter-porosity distribution of the reservoir core to be tested under different pressures;
5) According to the pore diameter-porosity distribution of the rock core of the reservoir to be measured under different pressure values determined in the step 4), the change of the effective pore throats of the different scales of the tight reservoir under geological conditions is quantitatively evaluated, and therefore quantitative evaluation of the effectiveness of the pore throats of the different scales of the tight reservoir of the land-phase lake basin under geological conditions is achieved.
2. The quantitative evaluation method according to claim 1, wherein step 1) is achieved by: and (3) calibrating the porosity of the tight reservoir and the nuclear magnetic resonance signal by using a standard scale sample, so as to establish a relation between the nuclear magnetic resonance signal intensity and the porosity.
3. The quantitative evaluation method according to claim 1, wherein the reservoir core to be measured after saturation with water is obtained by subjecting the reservoir core to be measured to vacuum pressurization saturated water treatment.
4. The quantitative evaluation method according to claim 1, wherein the method further comprises:
t of reservoir core to be measured after saturated water measured in step 2), step 3) 2 The spectrum is combined with the relation established in the step 1), and the porosity of the reservoir rock core to be measured under different pressures is calculated; and quantitatively evaluating the change of the porosity of the tight reservoir under geological conditions.
5. The quantitative evaluation method according to claim 1, wherein the confining pressure value in step 3) is 3MPa, 6MPa, 9MPa, 12MPa.
6. The quantitative evaluation method according to claim 1 or 5, wherein the sequential application of confining pressures of different pressure values in step 3) is achieved by sequentially applying confining pressures of from small to large pressure values.
7. The quantitative evaluation method according to claim 1, wherein in step 3), the confining pressure of different pressure values is sequentially applied to the reservoir core to be measured after saturated water, and the confining pressure is applied by using an external simulation clamp.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911093659.5A CN111006985B (en) | 2019-11-11 | 2019-11-11 | Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911093659.5A CN111006985B (en) | 2019-11-11 | 2019-11-11 | Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111006985A CN111006985A (en) | 2020-04-14 |
| CN111006985B true CN111006985B (en) | 2023-05-26 |
Family
ID=70111768
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911093659.5A Active CN111006985B (en) | 2019-11-11 | 2019-11-11 | Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111006985B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111610130B (en) * | 2020-05-30 | 2022-05-31 | 中国石油天然气股份有限公司 | Large-scale fresh water lake basin continental facies mud shale oil reservoir pore formation and evolution evaluation method |
| CN112557277B (en) * | 2020-12-07 | 2022-03-25 | 北京科技大学 | Compact rock micropore connectivity identification classification evaluation method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103926267A (en) * | 2014-04-28 | 2014-07-16 | 西安石油大学 | Method for quantitatively evaluating pore throat change degree in stress sensitive process |
| CN106770415A (en) * | 2016-12-13 | 2017-05-31 | 中国石油天然气股份有限公司 | Method for evaluating micro-flowability of high-viscosity low-fluidity compact oil under different temperature and pressure conditions |
| CN107727679A (en) * | 2017-11-03 | 2018-02-23 | 中国科学院地质与地球物理研究所 | One kind characterizes Deep Carbonate Rocks petrophysics characterization method |
| CN107894386A (en) * | 2017-11-14 | 2018-04-10 | 西安石油大学 | The quantitative evaluation method that supercritical carbon dioxide injection influences on low permeability sandstone reservoir pore throat character |
| CN108458960A (en) * | 2018-03-27 | 2018-08-28 | 中国石油大学(华东) | A kind of hydrogeneous component of richness organic matter mud shale, porosity and the evaluation method in aperture |
| CN109612897A (en) * | 2018-09-25 | 2019-04-12 | 西安石油大学 | The quantitative evaluation method that produced-water reinjection influences tight sand physical property and throat distribution |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10551520B2 (en) * | 2014-11-13 | 2020-02-04 | Colorado School Of Mines | Surface relaxivity calculation using nuclear magnetic resonance (NMR) measurement, three dimensional (3D) rock model and NMR response simulation |
-
2019
- 2019-11-11 CN CN201911093659.5A patent/CN111006985B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103926267A (en) * | 2014-04-28 | 2014-07-16 | 西安石油大学 | Method for quantitatively evaluating pore throat change degree in stress sensitive process |
| CN106770415A (en) * | 2016-12-13 | 2017-05-31 | 中国石油天然气股份有限公司 | Method for evaluating micro-flowability of high-viscosity low-fluidity compact oil under different temperature and pressure conditions |
| CN107727679A (en) * | 2017-11-03 | 2018-02-23 | 中国科学院地质与地球物理研究所 | One kind characterizes Deep Carbonate Rocks petrophysics characterization method |
| CN107894386A (en) * | 2017-11-14 | 2018-04-10 | 西安石油大学 | The quantitative evaluation method that supercritical carbon dioxide injection influences on low permeability sandstone reservoir pore throat character |
| CN108458960A (en) * | 2018-03-27 | 2018-08-28 | 中国石油大学(华东) | A kind of hydrogeneous component of richness organic matter mud shale, porosity and the evaluation method in aperture |
| CN109612897A (en) * | 2018-09-25 | 2019-04-12 | 西安石油大学 | The quantitative evaluation method that produced-water reinjection influences tight sand physical property and throat distribution |
Non-Patent Citations (1)
| Title |
|---|
| 四川盆地涪陵地区龙马溪组页岩微观孔隙结构定性定量研究;杨文新等;《石油实验地质》;20180131;第40卷(第01期);第97-102页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111006985A (en) | 2020-04-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102954978B (en) | A kind of Magnetic resonance imaging observation device of coal petrography fracture development process and method | |
| CN107807143B (en) | Low-field nuclear magnetic resonance multi-probe quantitative test system and method special for hydrate | |
| CN109030311B (en) | Based on nuclear magnetic resonance T2Method for classifying and identifying pore structure of spectrum sensitive parameter | |
| US11378509B2 (en) | Evaluation method for hydrogen-bearing components, porosity and pore size distribution of organic-rich shale | |
| Sigal | Pore-size distributions for organic-shale-reservoir rocks from nuclear-magnetic-resonance spectra combined with adsorption measurements | |
| CN105866002B (en) | A kind of accurate dice NMR porosity test method | |
| Wang et al. | Experimental study on the wettability of Longmaxi gas shale from Jiaoshiba gas field, Sichuan Basin, China | |
| CN111006985B (en) | Quantitative evaluation method for pore throat effectiveness of dense reservoir of land lake basin under geological conditions | |
| Zhao et al. | Multi-scale pore structure characterization of lacustrine shale and its coupling relationship with material composition: An integrated study of multiple experiments | |
| CN108444881B (en) | Characterization method suitable for continental facies shale micro-nano scale reservoir space | |
| CN103353462A (en) | Rock heterogeneous quantitative evaluation method based on magnetic resonance imaging | |
| CN113075102B (en) | Method for establishing mathematical model of relation between spontaneous imbibition amount of porous medium and time | |
| Zhang et al. | In-situ observation for natural gas hydrate in porous medium: Water performance and formation characteristic | |
| Hu et al. | A method to determine nuclear magnetic resonance T2 cutoff value of tight sandstone reservoir based on multifractal analysis | |
| Tian et al. | Rock-type definition and pore characterization of tight carbonate rocks based on thin sections and MICP and NMR experiments | |
| CN111827968B (en) | Reservoir heterogeneity evaluation method and device based on nuclear magnetic resonance logging | |
| Zhang et al. | A testing assembly for combination measurements on gas hydrate-bearing sediments using x-ray computed tomography and low-field nuclear magnetic resonance | |
| Maojin et al. | Nuclear magnetic resonance simulations of nano-scale cores and microscopic mechanisms of oil shale | |
| CN113189129A (en) | Rock crack porosity detection process | |
| CN112129802A (en) | Quantitative analysis method for volume increment of different-scale pores of hydrated shale | |
| CN110687155A (en) | Method for testing water thickness of soil film | |
| CN112526622B (en) | Quasi-nuclear magnetic echo data calculation method based on imaging logging porosity spectrum | |
| Li et al. | Pore size distribution of a tight sandstone reservoir and its effect on micro pore‐throat structure: a case study of the Chang 7 member of the Xin'anbian Block, Ordos Basin, China | |
| CN111426617B (en) | Quantitative prediction method for porosity of dense reservoir of land lake basin under geological conditions | |
| CN113405962B (en) | Storage space evaluation method and device for carbonate 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 |