CN111812736B - Method for evaluating gas content of compact sandstone anhydrous gas reservoir - Google Patents
Method for evaluating gas content of compact sandstone anhydrous gas reservoir Download PDFInfo
- Publication number
- CN111812736B CN111812736B CN202010714325.1A CN202010714325A CN111812736B CN 111812736 B CN111812736 B CN 111812736B CN 202010714325 A CN202010714325 A CN 202010714325A CN 111812736 B CN111812736 B CN 111812736B
- Authority
- CN
- China
- Prior art keywords
- curve
- gas
- gas content
- content
- sandstone
- 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
- 238000000034 method Methods 0.000 title claims abstract description 50
- 239000007789 gas Substances 0.000 claims abstract description 136
- 238000011156 evaluation Methods 0.000 claims abstract description 55
- 239000011435 rock Substances 0.000 claims abstract description 36
- 101100058498 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) CNL1 gene Proteins 0.000 claims abstract description 19
- 101100401683 Schizosaccharomyces pombe (strain 972 / ATCC 24843) mis13 gene Proteins 0.000 claims abstract description 19
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000001257 hydrogen Substances 0.000 claims abstract description 15
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 15
- 101100294209 Schizosaccharomyces pombe (strain 972 / ATCC 24843) cnl2 gene Proteins 0.000 claims abstract description 8
- 238000004364 calculation method Methods 0.000 claims description 28
- 238000004458 analytical method Methods 0.000 claims description 16
- 238000012937 correction Methods 0.000 claims description 9
- 238000001228 spectrum Methods 0.000 claims description 9
- 238000003921 particle size analysis Methods 0.000 claims description 5
- 239000000706 filtrate Substances 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 230000000704 physical effect Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 2
- 238000007405 data analysis Methods 0.000 claims 2
- 238000010606 normalization Methods 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 9
- 239000008398 formation water Substances 0.000 abstract description 8
- 238000009412 basement excavation Methods 0.000 abstract description 7
- 239000003345 natural gas Substances 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000012512 characterization method Methods 0.000 abstract 1
- 238000011160 research Methods 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000010291 electrical method Methods 0.000 description 5
- 235000019738 Limestone Nutrition 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000006028 limestone Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000005481 NMR spectroscopy Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 102100033538 Clusterin-associated protein 1 Human genes 0.000 description 1
- 101000945057 Danio rerio Clusterin-associated protein 1 homolog Proteins 0.000 description 1
- 208000035126 Facies Diseases 0.000 description 1
- 101000945060 Homo sapiens Clusterin-associated protein 1 Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001225 nuclear magnetic resonance method Methods 0.000 description 1
- 238000011158 quantitative evaluation Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004457 water analysis Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
- G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
- G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
- G01V5/10—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
-
- 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
- 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
- G01N23/005—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 using neutrons
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- High Energy & Nuclear Physics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Geophysics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Dispersion Chemistry (AREA)
- Geophysics And Detection Of Objects (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
The invention discloses a method for evaluating gas content of a compact sandstone anhydrous gas reservoir, which solves the technical problem of low evaluation precision of the gas content of the compact sandstone anhydrous gas reservoir in the prior art. The invention mainly calculates the mud content curve V in turnshEffective porosity curve phieThe gas content evaluation method comprises the following steps of obtaining a pure rock neutron curve CNL1, an apparent sandstone skeleton hydrogen content index curve CNL2 and a gas content evaluation index parameter GASFG curve, and finally carrying out gas content evaluation according to the gas content evaluation index parameter GASFG curve. The invention fully utilizes the excavation effect of natural gas on the neutron logging curve to carry out quantitative characterization of gas content index parameters, and effectively solves the technical problem that the reservoir gas content of the compact sandstone in the prior art is difficult to accurately evaluate under the condition of lacking of information such as formation water and the like through classification evaluation. Practice proves that the technology can not only accurately evaluate the gas content of the compact sandstone anhydrous gas reservoir, but also effectively identify the high-gamma reservoir, thereby providing an accurate exploration method for oil-gas exploration.
Description
Technical Field
The invention belongs to the technical field of gas reservoir exploration and development, and particularly relates to a method for evaluating gas content of a compact sandstone anhydrous gas reservoir.
Background
In recent years, the exploration result of compact sandstone in narrow rivers in the group of the Jurashi temple in the Jurassic area in mid-autumn forest in Sichuan has shown that the source storage in the area is well configured, which is beneficial to the facies development of reservoirs. At present, the trial results of the new well and the old well in the block prove that the sand group 5, the sand group 8 and the sand group 11 of the Shaxi temple all obtain high-yield gas wells, no formation water is produced, and good exploration potential is shown. With the continuous and intensive research, some wells in the research area are found to show good reservoir characteristics on the well logging curve, but the test result is an empty layer. The exploration practice proves that the gas content evaluation and the reservoir effectiveness evaluation of the reservoir have important significance. Currently, the evaluation of air entrainment in the sand body group of the Shaxi temple in the research area is one of the efforts of oil and gas exploration researchers.
At present, a gas saturation (Sg) parameter is generally adopted as an important index for evaluating the gas content of a tight sandstone reservoir, and the parameter acquisition method mainly comprises the steps of directly measuring in a closed and cored laboratory, and carrying out gas saturation inversion and well logging data calculation based on capillary pressure data. (1) And (4) directly measuring the saturation of the gas in the closed core. The method is restricted by factors such as drilling engineering technology, coring conditions, laboratory measuring equipment and the like, and is inconvenient for widely developing application research in areas. (2) The invention is based on the principle that the invention is disclosed by the invention patent (patent number: CN201410602210.8) based on the rock-capillary model for back calculation of the gas saturation. Although the method has simple calculation principle and is easy to implement, a lot of uncertainties exist. Firstly, capillary pressure data is influenced by experimental means and experimental conditions, and the precision of the capillary pressure data is uncertain; secondly, the method needs to convert the capillary pressure under the laboratory condition into the uncertainty under the gas reservoir condition, and the uncertainty exists in the determination of parameters such as interfacial tension, wetting angle and the like; thirdly, the method is applied on the premise that the gas-water interface and the gas column height are determined, and large uncertainty exists. This method is also a relatively low accuracy method. (3) Obtaining gas saturation from well log data is the most common method. The water saturation (Sw) is typically calculated first by the saturation equation and the gas saturation is calculated using equation 1.
Sg＝1-Sw (1)
As is well known, many studies have been conducted at home and abroad to calculate the water saturation by using well logging data, and the water saturation can be mainly divided into an electrical method and a non-electrical method, and the electrical method is mainly used. From the publication of Archie's formula in 1942, many electrical method saturation models exist, for example, the invention patent (patent number: CN201910760689.0) discloses a compact sandstone gas saturation calculation method based on calcium content correction. Although many models are used to calculate saturation, several parameters in common in the models are critical to the calculation result. That is the electrical parameters a, b, m and n and the formation water resistivity Rw. The rock-electricity parameters can be obtained by rock-electricity experiments under simulated formation conditions. However, similar to the situation of no formation water production in the research area, because formation water analysis data cannot be obtained, calculation can be performed only by using data or empirical parameters of the adjacent area, and the calculation result is often not practical, which brings difficulty to the evaluation of gas bearing property. The methods for determining the gas saturation by the non-electric method mainly comprise a sound wave method, a neutron method and a nuclear magnetic resonance method. For example, the invention patent (patent number: CN201811323041.9) discloses a method for identifying a gas layer by using element gamma energy spectrum logging, and the saturation of the gas in the stratum is determined according to the ratio (R) of the non-elastic gamma counting rate of fast neutrons to the thermal neutron capture gamma counting rate. The method needs to establish a response equation among gas saturation, porosity and R, the equation is influenced by too many factors, the non-elastic gamma counting rate obtained by fast neutrons is related to lithology, and the influence of the lithology is large; secondly, the thermal neutron capture gamma counting is greatly influenced by elements with strong capture capacity in the stratum; most importantly, the adaptability of this equation is not demonstrated in the field. The invention patent (patent number: CN201611263196.9) discloses a gas saturation determination method and a gas saturation determination device based on longitudinal and transverse wave logging speeds. The method obtains a gas saturation calculation formula based on experiments, and has a complex process and low practicability. Because it is difficult to extract the parameters of the first longitudinal wave time difference and the second longitudinal wave time difference in the well logging data. In addition, the nuclear magnetic resonance logging can better evaluate the gas content by determining the porosity which is independent of the lithology. However, the method is high in cost, and a research area cannot acquire a large amount of nuclear magnetic resonance logging information, so that the method is not suitable for comprehensively evaluating the gas content in the area.
In a word, the gas content evaluation method is influenced by multiple factors such as difficulty in mass sampling for coring, difficulty in experimental method, experimental conditions and data shortage, uncertainty of evaluation results is high, and evaluation precision is difficult to meet production requirements. However, for a long time, people are used to qualitatively describe the gas layer by using the excavation effect phenomenon of neutron logging, but no report on quantitative evaluation is found. The invention provides a novel gas content evaluation index and evaluation method, which can effectively solve the technical problem of low precision of evaluation results in the prior art.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method for evaluating the gas content of the compact sandstone anhydrous gas reservoir solves the technical problem that the evaluation precision of the gas content of the compact sandstone anhydrous gas reservoir is low in the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
an anhydrous compact sandstone gas reservoir gas content evaluation method comprises the following steps:
step 2, calculating the effective porosity phi e, and calibrating by using the core physical property analysis data;
step 3, carrying out shale correction on the neutron logging curve by using the shale content Vsh calculated in the step 1 to obtain a neutron curve CNL1 of pure rock;
step 4, converting the pure rock neutron curve CNL1 in the step 3 into a sandstone skeleton hydrogen-containing index curve CNL 2;
step 5, calculating a gassiness evaluation index parameter GASFG curve by using the porosity phi e calculated in the step 2 and the CNL2 curve obtained in the step 4 and adopting a rock volume physical model;
and 6, evaluating the gas content by using the gas content evaluation index parameter GASFG curve calculated in the step 5.
Further, in the step 1, a natural gamma curve or a natural gamma energy spectrum curve is adopted for carrying out
Where Sh is the relative value of natural gamma, GR is the measured value of natural gammaminNatural gamma value, GR, for pure sandstonemaxNatural gamma value of pure mudstone; GCUR is the empirical coefficient associated with the age of the geology, taking 2 for old strata and 3.7 for new strata.
Further, in step 1, the natural gamma curve or the natural gamma energy spectrum curve refers to a logging curve after filtering and regional standardization.
Further, the rock core data refers to the reset rock core shale content data; preferably, the data is full-rock clay analysis data or full-rock particle size analysis data.
Further, in the step 2, calculating the effective porosity Φ e by using the acoustic wave or the density log; preferably, the effective porosity Φ e is calculated as:
ΔT＝Φe.ΔTmf+Vsh.ΔTsh+Vma.ΔTma；
Φe+Vsh+Vma＝1；
wherein, Delta T is a sound wave time difference curvemfAcoustic time difference, Δ T, for mud filtrateshIs the mudstone acoustic time difference, Δ TmaFor the acoustic time difference of the skeleton, VmaIs a sandstone stock price volume.
Further, in the step 2, the sound wave or density curve needs to be standardized; preferably, the porosity of the core needs to be subjected to deep homing treatment; further preferably, after core analysis porosity calibration, the effective porosity Φ e error obtained by logging calculation needs to be within an error range specified by a reserve specification.
Further, in step 3, the calculation formula for performing shale correction on the neutron log is as follows:
CNL1＝CNL-Vsh.ΦNsh；
wherein, CNL is neutron logging value,
is the mudstone neutron value;
preferably, phi in the above formulaNshDetermined from the GR and CNL cross plots.
Further, in the step 4, the calculation formula for converting the pure rock neutron curve CNL1 into the sandstone skeleton hydrogen index curve CNL2 is as follows:
further, in the step 5, a calculation formula for calculating the gassiness evaluation index parameter GASFG curve is:
further, in the step 6, the evaluation index for evaluating the gas inclusion property by using the gas inclusion property evaluation index parameter GASFG curve is: the GASFG is greater than 0.9 and is a gas layer, the GASFG is between 0.7 and 0.9 and is a gas-poor layer, the GASFG is between 0.5 and 0.7 and is a gas-containing layer, and the GASFG is less than 0.5 and is a dry layer or a non-reservoir layer.
Compared with the prior art, the invention has the following beneficial effects:
the method has scientific and reasonable design and wonderful conception, fully utilizes the excavation effect of natural gas on the neutron logging curve to carry out quantitative calculation of the gas content index parameters, effectively solves the technical problem that the gas content of the anhydrous compact sandstone gas reservoir in the prior art cannot be accurately evaluated under the condition of lacking of information such as formation water and the like through classification evaluation, and can effectively evaluate the gas content of the anhydrous sandstone gas reservoir and identify a high-gamma reservoir, thereby providing an accurate exploration method for oil-gas exploration.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a diagram of the results of the present invention in evaluating the gas bearing capacity of a autumn forest 16 well.
FIG. 3 is a chart of the results of the present invention in evaluating the gas bearing capacity of a autumn forest 208 well.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and thus, it should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; of course, mechanical connection and electrical connection are also possible; alternatively, they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
As shown in fig. 1, the method for evaluating the gas content of the anhydrous tight sandstone gas reservoir provided by the invention comprises the following steps:
further, in the step 1, a natural gamma curve or a natural gamma energy spectrum curve is adopted for carrying out
Where Sh is the relative value of natural gamma, GR is the measured value of natural gammaminNatural gamma value, GR, for pure sandstonemaxNatural gamma value of pure mudstone; GCUR is the empirical coefficient associated with the age of the geology, taking 2 for old strata and 3.7 for new strata.
The natural gamma curve or the natural gamma energy spectrum curve refers to a logging curve after filtering and regional standardization. The core data refers to the restored core mass content data; preferably, the data is full-rock clay analysis data or full-rock particle size analysis data.
And 2, calculating the effective porosity phi e, and calibrating by using the core physical property analysis data. And when the effective porosity phi e is calculated, calculating the effective porosity phi e by utilizing the acoustic wave or the density logging curve. The effective porosity Φ e is calculated as:
ΔT＝Φe.ΔTmf+Vsh.ΔTsh+Vma.ΔTma；
Φe+Vsh+Vma＝1；
wherein, Delta T is a sound wave time difference curvemfAcoustic time difference, Δ T, for mud filtrateshIs the mudstone acoustic time difference, Δ TmaFor the acoustic time difference of the skeleton, VmaIs the volume of the sandstone framework.
The sound wave or density curve needs to be standardized; the porosity of the core needs to be subjected to deep homing treatment; after core analysis porosity calibration, the error of the effective porosity phi e obtained by logging calculation needs to be within the error range specified by the reserves specification.
And 3, performing argillaceous correction on the neutron logging curve by using the argillaceous content Vsh calculated in the step 1 to obtain a neutron curve CNL1 of pure rock. The calculation formula for performing the shale correction on the neutron well logging curve is as follows:
CNL1＝CNL-Vsh.ΦNsh；
wherein, CNL is neutron logging value,
is the mudstone neutron value;
preferably, phi in the above formulaNshDetermined from the GR and CNL cross plots.
And 4, converting the pure rock neutron curve CNL1 in the step 3 into a sandstone skeleton hydrogen-containing index curve CNL 2. The CNL1 neutron logging curve obtained in step 3 is actually an apparent limestone hydrogen index curve, so the apparent limestone hydrogen index curve CNL1 needs to be converted into a sandstone skeleton hydrogen index curve CNL2, and the calculation formula for converting the pure rock neutron curve CNL1 into a sandstone skeleton hydrogen index curve CNL2 is as follows:
and 5, calculating a gassiness evaluation index parameter GASFG curve by using the porosity phi e calculated in the step 2 and the CNL2 curve obtained in the step 4 and adopting a rock volume physical model. The calculation formula for calculating the gassiness evaluation index parameter GASFG curve is as follows:
and 6, evaluating the gas content by using the gas content evaluation index parameter GASFG curve calculated in the step 5. The evaluation indexes for evaluating the gas content by using the gassiness evaluation index parameter GASFG curve are as follows: the GASFG is greater than 0.9 and is a gas layer, the GASFG is between 0.7 and 0.9 and is a gas-poor layer, the GASFG is between 0.5 and 0.7 and is a gas-containing layer, and the GASFG is less than 0.5 and is a dry layer or a non-reservoir layer.
The method has scientific and reasonable design and wonderful conception, fully utilizes the excavation effect of natural gas on the neutron logging curve to carry out quantitative calculation of the gas content index parameters, effectively solves the technical problem that the gas content of the anhydrous compact sandstone gas reservoir in the prior art cannot be accurately evaluated under the condition of lacking of information such as formation water and the like through classification evaluation, and can effectively evaluate the gas content of the anhydrous sandstone gas reservoir and identify a high-gamma reservoir, thereby providing an accurate exploration method for oil-gas exploration.
In order to enable a person skilled in the art to better understand the technical scheme, the technology of the invention is described in detail by taking a autumn forest 16-well dwarashium series salxi temple group compact sandstone reservoir as an example:
1. calculating the mud content Vsh by using a natural gamma or natural gamma energy spectrum curve:
GRminnatural gamma value, GR, for pure sandstonemaxIs the natural gamma value of pure mudstone.
2. Method for calculating effective porosity phi e of reservoir by utilizing sound waves
ΔT＝Φe.ΔTmf+Vsh.ΔTsh+Vma.ΔTma；
Φe+Vsh+Vma＝1；
Δ T is the sonic time difference curve, Δ TmfMud filtrate acoustic time difference, Δ TshIs the mudstone acoustic time difference, Δ TmaIs the acoustic time difference of the skeleton.
3. Conversion of the neutron curve CNL1 in pure rock. For an anhydrous sandstone gas reservoir, the neutron log is affected by the combined action of effective porosity, shale content and excavation effect. Firstly, performing shale correction on the compensation neutron curve CNL to obtain a neutron logging curve CNL1 of pure rock.
CNL1＝CNL-Vsh.ΦNsh；
In the formula phiNshIt should be determined from the GR and CNL cross-plots.
4. Apparent sandstone hydrogen index curve (CNL 2). According to the rock volume physical model, the apparent limestone hydrogen index curve CNL1 of pure rock is used for calculating to obtain the apparent sandstone skeleton hydrogen index curve CNL 2.
To obtain
5. Calculating a gassiness evaluation index parameter curve GASFG, wherein the calculation formula is as follows:
6. and performing gas-containing classification evaluation by using a gas-containing evaluation index parameter curve GASFG, wherein a gas layer is formed when the GASFG is more than 0.9, a gas layer is formed when the GASFG is between 0.7 and 0.9, a gas layer is formed when the GASFG is between 0.5 and 0.7, and a dry layer or a non-reservoir layer is formed when the GASFG is less than 0.5. The results of the qilin 16 well gas bearing evaluation are shown in fig. 2.
Taking autumn forest 16 wells and autumn forest 208 wells as examples, the gas bearing results evaluated by the technology of the invention have good evaluation effects, the evaluation results are shown in fig. 2 and 3, the evaluation results are consistent with the test conditions of the two wells, the water saturation recognition results are superior to the water saturation recognition results calculated by a conventional electrical method, and the high gamma reservoir recognition can be effectively carried out.
The method has scientific and reasonable design and wonderful conception, fully utilizes the excavation effect of natural gas on the neutron logging curve to carry out quantitative calculation of the gas content index parameters, and effectively solves the technical problem that the accurate gas content evaluation can not be carried out under the condition that the anhydrous compact sandstone gas is hidden in the lack of the formation water and other data in the prior art through classification evaluation. The method of the invention obtains good effect by applying the anhydrous compact sandstone gas reservoir in the Jurassic series Shaxi temple group in the autumn forest area. By utilizing the method, the gas content of the anhydrous sandstone gas reservoir can be effectively evaluated and the high-gamma reservoir can be effectively identified, so that the aim of better providing service for oil and gas exploration is fulfilled.
The invention provides an evaluation index of gas content of an anhydrous compact sandstone gas reservoir by utilizing the principle of the excavation effect of natural gas on neutron logging, and performs classified evaluation of the gas content on the basis. Practice proves that the index not only can accurately evaluate the gas content, but also can effectively identify the high-gamma reservoir of the research area. The method for calculating the gas content evaluation index comprises the following steps: calculating the argillaceous content Vsh; calculating the effective porosity phi of the reservoir; performing mud correction according to a hydrogen index curve of limestone; converting the hydrogen-containing index curve of the pure rock visual sandstone; quantitatively calculating the gas content evaluation index; and (4) classified evaluation of air inclusion. The method can effectively solve the technical problem that the prior art is limited by multiple factors such as difficulty in mass sampling, experimental method, experimental conditions, lack of data and the like, so that the evaluation result is low in precision.
Finally, it should be noted that: the above embodiments are only preferred embodiments of the present invention to illustrate the technical solutions of the present invention, but not to limit the technical solutions, and certainly not to limit the patent scope of the present invention; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; that is, the technical problems to be solved by the present invention, which are not substantially changed or supplemented by the spirit and the concept of the main body of the present invention, are still consistent with the present invention and shall be included in the scope of the present invention; in addition, the technical scheme of the invention is directly or indirectly applied to other related technical fields, and the technical scheme is included in the patent protection scope of the invention.
Claims (16)
1. The method for evaluating the gas content of the compact sandstone anhydrous gas reservoir is characterized by comprising the following steps of:
step 1, calculating the argillaceous content VshCalibrating the rock core whole rock analysis data or the granularity analysis data;
step 2, calculating the effective porosity phieAnd calibrating by using the physical property analysis data of the rock core;
step 3, utilizing the calculated argillaceous content V in the step 1shPerforming shale correction on the neutron log to obtain a neutron curve CNL1 of pure rock;
step 4, converting the pure rock neutron curve CNL1 in the step 3 into a sandstone skeleton hydrogen-containing index curve CNL 2;
step 5, utilizing the porosity phi calculated in the step 2eCalculating a gassiness evaluation index parameter GASFG curve by adopting a rock volume physical model together with the CNL2 curve obtained in the step 4;
and 6, evaluating the gas content by using the gas content evaluation index parameter GASFG curve calculated in the step 5.
2. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir of claim 1, wherein in the step 1, the calculation of the shale content Vsh is performed by using a natural gamma curve or a natural gamma energy spectrum curve.
3. The tight sandstone anhydrous gas reservoir gas content evaluation method of claim 2, wherein the calculation formula of the shale content Vsh is as follows:
where Sh is the relative value of natural gamma, GR is the measured value of natural gammaminNatural gamma value, GR, for pure sandstonemaxThe natural gamma value of pure mudstone, GCUR is an empirical coefficient related to the age of the geology, and 2 is taken for the old stratum and 3.7 is taken for the new stratum.
4. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir of claim 2, wherein in the step 1, the natural gamma curve or the natural gamma energy spectrum curve refers to a logging curve after filtering and regional standardization.
5. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir as claimed in claim 1, wherein the rock core whole rock analysis data or particle size analysis data refers to the restored rock core shale content data.
6. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir according to claim 5, wherein the rock core full-rock analysis data or particle size analysis data are full-rock clay analysis data or data obtained by full-rock particle size analysis.
7. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir of claim 1, wherein the step 2 uses soundCalculating effective porosity phi from wave or density well logging curvee。
8. The method of claim 7, wherein the effective porosity phi is determined by the method for evaluating the gas content of the tight sandstone anhydrous gas reservoireThe calculation formula is as follows:
ΔT＝Φe.ΔTmf+Vsh.ΔTsh+Vma.ΔTma；
Φe+Vsh+Vma＝1；
wherein, Delta T is a sound wave time difference curvemfAcoustic time difference, Δ T, for mud filtrateshIs the mudstone acoustic time difference, Δ TmaFor sandstone frameworks acoustic time difference, VmaIs the volume of the sandstone framework.
9. The tight sandstone anhydrous gas reservoir gas content evaluation method of claim 7, wherein in the step 2, the sonic or density log is subjected to a normalization process.
10. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir of claim 9, wherein in the step 2, the core analysis porosity is subjected to deep homing.
11. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir according to claim 10, wherein after core analysis porosity calibration, an effective porosity Φ e error obtained by logging calculation is required to be within an error range specified by a reserve specification.
12. The tight sandstone anhydrous gas reservoir gas content evaluation method of claim 1, wherein in the step 3, the calculation formula for performing the shale correction on the neutron logging curve is as follows:
CNL1＝CNL-Vsh.ΦNsh；
wherein CNL is neutron log value, phiNshIs the mudstone neutron value.
13. The method for evaluating the gas content of the tight sandstone anhydrous gas reservoir of claim 12, wherein the phi isNshDetermined from the GR and CNL cross plots.
14. The tight sandstone anhydrous gas reservoir gas content evaluation method of claim 1, wherein in the step 4, the calculation formula for converting the pure rock neutron curve CNL1 into the sandstone skeleton hydrogen-containing index curve CNL2 is as follows:
15. the method for evaluating the gas content of the tight sandstone anhydrous gas reservoir according to claim 1, wherein in the step 5, a calculation formula for calculating a gassiness evaluation index parameter GASFG curve is as follows:
16. the method for evaluating the gas content of the tight sandstone anhydrous gas reservoir according to claim 1, wherein in the step 6, the evaluation indexes of the gas content evaluation by using a gas content evaluation index parameter GASFG curve are as follows: the GASFG is greater than 0.9 and is a gas layer, the GASFG is between 0.7 and 0.9 and is a gas-poor layer, the GASFG is between 0.5 and 0.7 and is a gas-containing layer, and the GASFG is less than 0.5 and is a dry layer or a non-reservoir layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010714325.1A CN111812736B (en) | 2020-07-22 | 2020-07-22 | Method for evaluating gas content of compact sandstone anhydrous gas reservoir |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010714325.1A CN111812736B (en) | 2020-07-22 | 2020-07-22 | Method for evaluating gas content of compact sandstone anhydrous gas reservoir |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111812736A CN111812736A (en) | 2020-10-23 |
| CN111812736B true CN111812736B (en) | 2021-03-16 |
Family
ID=72862210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010714325.1A Active CN111812736B (en) | 2020-07-22 | 2020-07-22 | Method for evaluating gas content of compact sandstone anhydrous gas reservoir |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111812736B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112814667B (en) * | 2021-01-05 | 2023-07-14 | 中海石油(中国)有限公司 | Method for evaluating water content of tight gas layer based on thermal neutron logging count rate ratio |
| CN113236237B (en) * | 2021-05-11 | 2022-05-03 | 西南石油大学 | Effectiveness evaluation method for compact sandstone reservoir based on conventional logging curve |
| CN113376699B (en) * | 2021-06-08 | 2022-04-29 | 西南石油大学 | Multi-mineral component calculation method based on single acoustic old well logging series |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101832133A (en) * | 2010-01-28 | 2010-09-15 | 中国石油集团川庆钻探工程有限公司 | Reservoir fluid type discrimination method based on difference value of density porosity and neutron porosity |
| CN106593423A (en) * | 2016-11-08 | 2017-04-26 | 中国石油天然气股份有限公司 | Method and device for identifying oil reservoir fluid type |
| CN107346455A (en) * | 2016-05-05 | 2017-11-14 | 中国石油化工股份有限公司 | A kind of method for identifying shale gas production capacity |
| CN108979629A (en) * | 2018-07-10 | 2018-12-11 | 中国海洋石油集团有限公司 | It is a kind of based on density, neutron, nuclear magnetic resonance log gas-bearing formation density calculation method |
| CN111241460A (en) * | 2020-01-19 | 2020-06-05 | 西安石油大学 | Complex compact reservoir porosity calculation method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9995842B2 (en) * | 2015-05-29 | 2018-06-12 | Schlumberger Technology Corporation | Borehole fluid and/or casing effect correction for pulsed neutron measurements |
-
2020
- 2020-07-22 CN CN202010714325.1A patent/CN111812736B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101832133A (en) * | 2010-01-28 | 2010-09-15 | 中国石油集团川庆钻探工程有限公司 | Reservoir fluid type discrimination method based on difference value of density porosity and neutron porosity |
| CN107346455A (en) * | 2016-05-05 | 2017-11-14 | 中国石油化工股份有限公司 | A kind of method for identifying shale gas production capacity |
| CN106593423A (en) * | 2016-11-08 | 2017-04-26 | 中国石油天然气股份有限公司 | Method and device for identifying oil reservoir fluid type |
| CN108979629A (en) * | 2018-07-10 | 2018-12-11 | 中国海洋石油集团有限公司 | It is a kind of based on density, neutron, nuclear magnetic resonance log gas-bearing formation density calculation method |
| CN111241460A (en) * | 2020-01-19 | 2020-06-05 | 西安石油大学 | Complex compact reservoir porosity calculation method |
Non-Patent Citations (2)
| Title |
|---|
| 四川盆地浅气层测井泥质参数校正模型;赵良孝 等;《天然气工业》;20071130;第27卷(第11期);第43-45页 * |
| 大庆徐家围子地区深部致密砂砾岩气层识别;黄布宙 等;《吉林大学学报（地球科学版）》;20031031;第33卷(第4期);第490-494页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111812736A (en) | 2020-10-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111812736B (en) | Method for evaluating gas content of compact sandstone anhydrous gas reservoir | |
| CN101930082B (en) | Method for discriminating reservoir fluid type by using resistivity data | |
| CN109254138B (en) | Water-rich evaluation method based on sandstone microcosmic characteristics | |
| WO2017024700A1 (en) | Device for calculating content of organic carbon in source rock | |
| CN106154351A (en) | A kind of evaluation method of low porosity permeability reservoir permeability | |
| EP0460927A2 (en) | Method for logging hydraulic characteristics of a formation | |
| CN105930932B (en) | The acquisition methods of shale gas-bearing formation standardization open-flow capacity based on gassiness index | |
| CN106468172A (en) | A kind of Oil in Super-low Permeability sandstone oil reservoir low-resistance reservoir log interpretation method | |
| CN109138975B (en) | Novel method for solving phase-permeability characteristic curve based on time-shifting logging data | |
| CN103306671A (en) | Four-quadrant reservoir type identification method and system | |
| CN112083515B (en) | Quantitative characterization and gas-bearing property evaluation method for excavation effect of low-resistance reservoir of tight sandstone | |
| CN110905493B (en) | Method for measuring pollution rate of underground stratum fluid | |
| Askari et al. | A fully integrated method for dynamic rock type characterization development in one of Iranian off-shore oil reservoir | |
| CN107728205A (en) | A kind of Formation pressure prediction method | |
| CN114370269A (en) | Comprehensive determination method for lower limit of physical property of effective reservoir of deep carbonate gas reservoir | |
| CN103698494B (en) | Method and device for determining saturation degree of hydrocarbon in lithologic trap | |
| CN111811988B (en) | Method for predicting gas-oil interface in trap based on fluid analysis and application thereof | |
| CN110322363A (en) | Shale gas reservoir reconstruction volume calculation method and system | |
| CN112746835B (en) | Optimized comprehensive evaluation method for deep shale gas geological dessert logging | |
| CN109655394B (en) | Nuclear magnetic resonance T2 spectrum permeability calculation method under constraint of throat structure parameters | |
| CN108412488B (en) | Logging method for rapidly determining organic porosity of shale gas reservoir | |
| CN114086938B (en) | Method for predicting gas saturation of heterogeneous sandstone reservoir | |
| RU2419111C2 (en) | Method to detect permeability of terrigenous container rocks | |
| CN112069444B (en) | Method and computer for calculating reservoir well testing permeability by using well logging data | |
| Yiren et al. | Simulation of mud invasion and analysis of resistivity profile in sandstone formation module |
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 |