Reservoir water content evaluation model constructed by nuclear magnetic resonance and microfluorescence fusion technology
The three-dimensional evaluation model of reservoir water content is constructed through nuclear magnetic resonance and microfluorescence fusion technology, which solves the problem of insufficient accuracy in the water content of reservoirs in the prior art, and achieves high accuracy quantitative evaluation.
Patent Information
- Application Number
- CN202111284168.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-11-01
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2041-11-01
AI Technical Summary
The prior art has insufficient accuracy in the judgment of reservoir water content, poor interpretation effects of conventional well recording and gas measurement, and lacks mutual verification methods of nuclear magnetic resonance and microfluorescence technology.
Using nuclear magnetic resonance and microfluorescence fusion technology, a three-dimensional stereoscopic evaluation model of water content in reservoirs was constructed through the movable water index, oil index and microfluorescence water-soluble hydrocarbon index analyzed by the third-sweep of nuclear magnetic resonance to achieve quantitative evaluation.
The accuracy of reservoir water content discrimination is improved, the shortcomings of inaccurate and qualitative description in the prior art are overcome, and a novel method for identifying well recording water content is provided.
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Figure CN116066089B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of reservoir water content evaluation methods, and is a reservoir water content evaluation model constructed by nuclear magnetic resonance and microscopic fluorescence fusion technology. Background Art
[0002] At present, there are many methods for evaluating reservoir oil content using logging technology, but there is a relative lack of methods for determining reservoir water content. Conventional logging and gas logging interpretation are not very effective in determining reservoir water content, and new logging methods are urgently needed to solve this problem. Traditional nuclear magnetic resonance and microfluorescence technologies both use spectral features to qualitatively evaluate reservoir fluid properties, lacking mutual verification methods and the application of interpretation models.
[0003] The nuclear magnetic resonance interpretations currently used in China are mostly two-dimensional intersection maps constructed using conventional parameters (such as nuclear magnetic resonance porosity, movable water saturation, etc.). The fluid properties are evaluated based on the distribution range of the intersection points. The intersection evaluation maps may have uneven distribution of landing points, resulting in inaccurate judgment of fluid properties.
[0004] The NMR parameters used in the above evaluation chart are obtained by measuring the ratio between pore signals and oil signals. However, the fluid in the rock sample is volatile. When the fluid evaporates, the pores are filled with exogenous water (saturated brine), which will cause misjudgment of reservoir water. Secondly, this evaluation method only uses NMR parameters to construct the chart, and the most effective T2 spectrum fluid property evaluation method is not fully utilized in the chart.
[0005] Core microscopic fluorescent thin section technology plays a unique role in identifying reservoir water content. It is the only technology that can observe the state of formation fluid in microscopic pores with the naked eye, and realizes the visualization of microscopic fluid occurrence. However, domestically, it is only a qualitative description, and quantitative evaluation of core water content has not been achieved. Summary of the invention
[0006] The present invention provides a reservoir water content evaluation model constructed by the fusion technology of nuclear magnetic resonance and micro-fluorescence, which overcomes the shortcomings of the above-mentioned prior art. It constructs a three-dimensional evaluation model of reservoir water content with the movable water index and oil content index of nuclear magnetic resonance three-scan analysis and the water-soluble hydrocarbon index of micro-fluorescence. The reservoir water content is quantitatively evaluated through the constructed three-dimensional evaluation model, thereby improving the accuracy of the evaluation.
[0007] The technical scheme of the present invention is achieved by the following measures: a reservoir water content evaluation model constructed by nuclear magnetic resonance and microscopic fluorescence fusion technology, comprising the following steps: step one, establishing a three-dimensional water content evaluation model: collecting core samples of several logging display layers, performing nuclear magnetic resonance and microscopic fluorescence thin section analysis on each collected core sample in the logging display section, obtaining nuclear magnetic resonance data of the core sample through nuclear magnetic resonance analysis, calculating a movable water index and an oil content index through the nuclear magnetic resonance data, obtaining microscopic fluorescence thin section data of the core sample through microscopic fluorescence thin section analysis, and calculating a water-soluble hydrocarbon index through the microscopic fluorescence thin section data; establishing a three-dimensional water content evaluation model with the movable water index as the X-axis, the oil content index as the Y-axis, and the water-soluble hydrocarbon index as the Z-axis;
[0008] Step 2, water content evaluation: perform nuclear magnetic resonance and microscopic fluorescence thin section analysis on the core samples of the logging display layer section of the evaluation well location, obtain nuclear magnetic resonance data of the core sample through nuclear magnetic resonance analysis, calculate the movable water index and oil content index through the nuclear magnetic resonance data, obtain microscopic fluorescence thin section data of the core sample through microscopic fluorescence thin section analysis, calculate the water-soluble hydrocarbon index through the microscopic fluorescence thin section data, locate the obtained movable water index as the X-axis value, the oil content index as the Y-axis value, and the water-soluble hydrocarbon index as the Z-axis value in the three-dimensional water content evaluation model, and obtain the reservoir water content determination result according to the located spatial orientation.
[0009] The following are further optimizations and / or improvements to the above technical solutions:
[0010] In the above-mentioned three-dimensional water content evaluation model, when the movable water index is less than 30%, the oil content index is greater than 20% and the water-soluble hydrocarbon index is 0, the reservoir is an oil layer; when the movable water index is less than 30%, the oil content index is less than 20% and the water-soluble hydrocarbon index is 0, the reservoir is a poor oil layer; when the movable water index is greater than 70%, the oil content index is greater than 5% and the water-soluble hydrocarbon index is greater than 10%, the reservoir is an oil-water mixed layer; when the movable water index is greater than 70%, the oil content index is less than 5% and the water-soluble hydrocarbon index is greater than or equal to 0, the reservoir is a water layer.
[0011] The above-mentioned NMR data include movable oil signal intensity, movable dry sweep signal intensity, relaxation time corresponding to T2 cutoff value, relaxation time at the end of NMR signal and movable oil saturation.
[0012] The above movable water index is calculated according to the following formula:
[0013] KDS=(Sg-Sy) / Sg*100% (1)
[0014] In formula (1), KDS is the movable water index (%), Sy is the movable oil signal area, and Sg is the movable dry sweep signal area.
[0015] The movable oil signal area is calculated by the following formula:
[0016]
[0017] In formula (2), Sy is the movable oil signal area, y is the movable oil signal intensity (unit: n / a), is the relaxation time corresponding to the T2 cutoff value (unit: ms); is the relaxation time at the end of the NMR signal (unit: ms).
[0018] The movable dry sweep signal area is calculated by the following formula:
[0019]
[0020] In formula (3), Sg is the movable dry sweep signal area, g is the movable dry sweep signal intensity (unit: n / a), is the relaxation time corresponding to the T2 cutoff value (unit: ms); is the relaxation time at the end of the NMR signal (unit: ms).
[0021] The above oil content index is calculated according to the following formula:
[0022] X=EXP(e i / 100) (4)
[0023]
[0024] In formulas (4) to (5), e i is the movable oil saturation (%), HYZ is the oil content index (%), X is the natural logarithm, X i is the natural logarithm of a single well, X min is the minimum natural logarithm of the region, X max is the maximum natural logarithm of the region.
[0025] The above-mentioned microscopic fluorescent thin-section data include the proportion of luminescent area of water-soluble hydrocarbons and the proportion of luminescent area of fluids.
[0026] The above water-soluble hydrocarbon index is the ratio of the luminous area of water-soluble hydrocarbons to the luminous area of fluid multiplied by 100%.
[0027] The present invention integrates the quantitative parameters of the nuclear magnetic resonance-derived parameters "mobile water index" and "oil content index" with the micro-fluorescence-derived parameter "water-soluble hydrocarbon index" to establish a nuclear magnetic resonance + micro-fluorescence water content evaluation model (i.e., a three-dimensional water content evaluation model). The model covers the most sensitive water content evaluation parameters in nuclear magnetic resonance and micro-fluorescence thin sections. Through dual verification by nuclear magnetic resonance and micro-fluorescence thin section technology, the accuracy of reservoir water content discrimination is greatly improved, and a new method for water content identification in logging is provided. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Attached Figure 1 This is the nuclear magnetic resonance + microscopic fluorescence water content evaluation model diagram of the present invention.
[0029] Attached Figure 2 This is the area spectrum of the NMR fluid oil signal.
[0030] Attached Figure 3 This is a picture of the processing of microscopic fluorescence photos using the digital application system for logging core microscopic fluorescence slices.
[0031] Attached Figure 4 This is the comprehensive logging diagram of Well M45.
[0032] Attached Figure 5 This is the NMR fluid oil signal area spectrum of M45 well.
[0033] Attached Figure 6 This is a microscopic fluorescence photograph of M45 well.
[0034] Attached Figure 7 This is the three-dimensional evaluation model diagram of the water content of M45 well.
[0035] Attached Figure 2 In the figure, area a is the movable oil signal area, and area b is the movable water signal area.
[0036] Attached Figure 3 In the figure, the dotted area in Figure a is the luminescent area of water-soluble hydrocarbons, and the dotted area in Figure b is the luminescent area of fluids; Figure 5 In the example, the dry sample signal is the dry sweep signal.
[0037] Attached Figure 5 In the figure, area a is the movable oil signal area, and area b is the movable water signal area.
[0038] Attached Figure 6 In the figure, a is the trace of water-soluble hydrocarbons and b is the trace of movable oil. DETAILED DESCRIPTION
[0039] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.
[0040] The attached Figure 2 , Attachment Figure 5 It is the T2 spectrum of nuclear magnetic resonance.
[0041] The present invention will be further described below in conjunction with embodiments:
[0042] Embodiment: The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microscopic fluorescence fusion technology includes the following steps: first, establishing a three-dimensional water content evaluation model: collecting core samples of several logging display layers, performing nuclear magnetic resonance and microscopic fluorescence thin section analysis on each core sample collected in the logging display section, obtaining nuclear magnetic resonance data of the core sample through nuclear magnetic resonance analysis, calculating a movable water index and an oil content index through the nuclear magnetic resonance data, obtaining microscopic fluorescence thin section data of the core sample through microscopic fluorescence thin section analysis, and calculating a water-soluble hydrocarbon index through the microscopic fluorescence thin section data; establishing a three-dimensional water content evaluation model (nuclear magnetic resonance-microscopic fluorescence water content three-dimensional evaluation model) with the movable water index as the X-axis, the oil content index as the Y-axis, and the water-soluble hydrocarbon index as the Z-axis;
[0043] Step 2, water content evaluation: perform nuclear magnetic resonance and microscopic fluorescence thin section analysis on the core samples of the logging display layer section of the evaluation well location, obtain nuclear magnetic resonance data of the core sample through nuclear magnetic resonance analysis, calculate the movable water index and oil content index through the nuclear magnetic resonance data, obtain microscopic fluorescence thin section data of the core sample through microscopic fluorescence thin section analysis, calculate the water-soluble hydrocarbon index through the microscopic fluorescence thin section data, locate the obtained movable water index as the X-axis value, the oil content index as the Y-axis value, and the water-soluble hydrocarbon index as the Z-axis value in the three-dimensional water content evaluation model, and obtain the reservoir water content determination result according to the located spatial orientation.
[0044] In the three-dimensional evaluation model of water content,
[0045] X-axis - movable water index (KDS): the ratio of NMR movable water signal to movable dry scan signal (%), reflecting the water content in the movable fluid of the reservoir, used to judge the properties of the reservoir fluid;
[0046] Y axis - Oil content index (HYZ): a derived parameter of movable oil saturation (%), reflecting the oil content in the movable fluid of the reservoir, used to evaluate whether it is a valuable layer;
[0047] Z-axis - water-soluble hydrocarbon index (SRT): The ratio of the luminescent area of water-soluble hydrocarbons to the luminescent area of fluids in the microscopic fluorescent slice is used to further determine the water content of the reservoir.
[0048] As an optimization of Example 1,
[0049] like Figure 1As shown in Table 1, in the three-dimensional water content evaluation model, when the movable water index is less than 30%, the oil content index is greater than 20% and the water-soluble hydrocarbon index is 0, the reservoir is an oil layer; when the movable water index is less than 30%, the oil content index is less than 20% and the water-soluble hydrocarbon index is 0, the reservoir is a poor oil layer; when the movable water index is greater than 70%, the oil content index is greater than 5% and the water-soluble hydrocarbon index is greater than 10%, the reservoir is an oil-water mixed layer; when the movable water index is greater than 70%, the oil content index is less than 5% and the water-soluble hydrocarbon index is greater than or equal to 0, the reservoir is a water layer.
[0050] The magnetic resonance data include movable oil signal intensity, movable dry sweep signal intensity, relaxation time corresponding to T2 cutoff value, relaxation time at the end of nuclear magnetic signal and movable oil saturation.
[0051] The movable water index is calculated according to the following formula:
[0052] KDS=(Sg-Sy) / Sg*100% (1)
[0053] In formula (1), KDS is the movable water index (%), Sy is the movable oil signal area, and Sg is the movable dry sweep signal area. Movable water index = (movable dry sweep signal area - movable oil signal area) / movable dry sweep signal area * 100%.
[0054] Movable dry sweep signal area = movable water signal area + movable oil signal area (see Figure 2 ).
[0055] Figure 2 The movable oil signal area in is calculated by the following formula:
[0056]
[0057] In formula (2), Sy is the movable oil signal area, y is the movable oil signal intensity (unit: n / a), is the relaxation time corresponding to the T2 cutoff value (unit: ms); is the relaxation time at the end of the NMR signal (unit: ms).
[0058] Figure 2 The movable dry sweep signal area is calculated by the following formula:
[0059]
[0060] In formula (3), Sg is the movable dry sweep signal area, g is the movable dry sweep signal intensity (unit: n / a), is the relaxation time corresponding to the T2 cutoff value (unit: ms); is the relaxation time at the end of the NMR signal (unit: ms).
[0061] The oil content index is calculated according to the following formula:
[0062] X=EXP(e i / 100) (4)
[0063]
[0064] In formulas (4) to (5), e i is the movable oil saturation (%), HYZ is the oil content index (%), X is the natural logarithm, X i is the natural logarithm of a single well, X min is the minimum natural logarithm of the region, X max is the maximum natural logarithm of the region.
[0065] X i , X min , X max All of them can be calculated according to formula (4).
[0066] The microscopic fluorescent slice data includes the luminescent area ratio of water-soluble hydrocarbons and the luminescent area ratio of fluids.
[0067] The microscopic fluorescence thin-section data (luminescent area of water-soluble hydrocarbons and luminescent area of fluids) are obtained by magnifying the data with a fluorescence microscope, taking photos, and then processing the photos with the conventional "mud logging core microscopic fluorescence thin-section digitization application system" in the art (see Figure 3 ).
[0068] The water-soluble hydrocarbon index is the ratio of the luminous area of water-soluble hydrocarbons to the luminous area of fluid multiplied by 100%.
[0069] In the present invention, the three-dimensional water content evaluation model effectively solves the problem of inaccurate fluid property identification caused by uneven distribution of intersection plate points, realizes quantitative evaluation of nuclear magnetic resonance and microfluorescence technology, and integrates the core quantitative parameters in nuclear magnetic resonance and microfluorescence to double-judge reservoir water content, thereby improving the innovation and accuracy of model evaluation. In 2020, the model achieved a compliance rate of 85% in water content identification of high-pressure reservoirs in the Junggar Basin (as verified in the case), which has a strong value for promotion and application.
[0070] Verification case:
[0071] Well M45 is located in the Mahu Sag in the Central Depression of the Junggar Basin. It is a pilot well deployed to explore the oil and gas content of the Upper Urho Formation in the Permian System in the eastern wing of the Baijiantan Fan in the Mahu Sag. When the well was drilled to a depth of 5099.00m, an abnormal gas logging was observed ( Figure 4); Coring was conducted at the well section from 5099.50m to 5107.20m, and 1.75m of oil spot-grade core and 0.41m of fluorescent-grade core were obtained. When the oil-bearing core came out of the barrel, the fresh section had a strong oil smell, and light brown crude oil was partially seeping out of the surface, with an oil-bearing area of 5% to 10%; the surface section of the fluorescent-grade core had a dry fluorescence of 20% to 70%, the bottom fluorescent area was reduced, and water dripping rapidly seeped out.
[0072] The cores were subjected to nuclear magnetic resonance analysis and microscopic fluorescence thin section analysis, and the analysis results were as follows:
[0073] NMR: Porosity: 10.05% to 12.09%, movable oil saturation: 3.74% to 7.73%, movable fluid saturation: 23.19% to 31.95%; T2 spectrum: Pore signal shows movable fluid, dry sweep signal partially overlaps with oil signal ( Figure 5 ).
[0074] Microscopic fluorescence: It mainly emits green-yellow light under the microscope, and is present in the form of fine throats and clusters. The light emission is weak to medium. The main light emission sites are in some interface cracks and intergranular pores. The light emission area is 15.23% to 17.40%. Light green water-soluble hydrocarbon traces can be seen locally ( Figure 6 ).
[0075] The movable water index, oil content index and water-soluble hydrocarbon index of microfluorescence were calculated by combining NMR data and microfluorescence data with formulas (1) to (5).
[0076] The calculated movable water index, oil content index and water-soluble hydrocarbon index in the three-dimensional water-bearing evaluation model are as follows: X-axis (KDS): 64% to 82%, and the reservoir points are distributed in the water-bearing area; Y-axis (HYZ): 5.92% to 14.82%, and the movable fluid oil content of the reservoir is low; Z-axis (SRT): 15% to 35%, and the traces of water-soluble hydrocarbons are obvious; after double verification by nuclear magnetic resonance and microfluorescence, the three-dimensional water-bearing evaluation model evaluates that this section of the reservoir is characterized by oil-water mixed layer (see Figure 7 ).
[0077] Well M45 was tested, and the test results showed that the daily oil production from 5100.00m to 5105.00m was 0.42t, and the daily water production was 7.80m 3 The oil test conclusion is that it is an oil-water layer, and the water content judgment of the three-dimensional water content evaluation model is consistent with the oil test conclusion.
[0078] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.
[0079] Table 1 Evaluation criteria of NMR+microfluorescence water content model
[0080] Fluid properties KDS(%) HYZ(%) SRT(%) Oil layer <30 >20 0 Poor oil layer <30 <20 0 Oil-water mixed layer >70 >5 >10 Water layer >70 <5 ≥0
Claims
1. A reservoir water content evaluation model constructed by nuclear magnetic resonance and microfluorescence fusion technology, characterized in that The following steps are involved: Step 1, establishing a three-dimensional water content evaluation model: collecting core samples of several logging display layers, performing nuclear magnetic resonance and microscopic fluorescence thin section analysis on each core sample collected in the logging display section, obtaining nuclear magnetic resonance data of the core sample through nuclear magnetic resonance analysis, and calculating the movable water index and oil content index using the nuclear magnetic resonance data; obtaining microscopic fluorescence thin section data of the core sample through microscopic fluorescence thin section analysis, and calculating the water-soluble hydrocarbon index using the microscopic fluorescence thin section data; establishing a three-dimensional water content evaluation model with the movable water index as the X-axis, the oil content index as the Y-axis, and the water-soluble hydrocarbon index as the Z-axis; Step 2, water content evaluation: nuclear magnetic resonance and microscopic fluorescence thin section analysis are respectively performed on the core samples of the logging display layer section of the evaluation well location, and the nuclear magnetic resonance data of the core samples are obtained by nuclear magnetic resonance analysis, and the movable water index and the oil content index are calculated by the nuclear magnetic resonance data. The microscopic fluorescence thin section data of the core samples are obtained by microscopic fluorescence thin section analysis, and the water-soluble hydrocarbon index is calculated by the microscopic fluorescence thin section data. The obtained movable water index is the X-axis value, the oil content index is the Y-axis value, and the water-soluble hydrocarbon index is the Z-axis value. Positioning is performed in the established three-dimensional water content evaluation model, and the reservoir water content evaluation result is obtained according to the spatial orientation of the positioning; Among them, in the three-dimensional water content evaluation model, when the movable water index is less than 30%, the oil content index is greater than 20% and the water-soluble hydrocarbon index is 0, the reservoir is an oil layer; when the movable water index is less than 30%, the oil content index is less than 20% and the water-soluble hydrocarbon index is 0, the reservoir is a poor oil layer; when the movable water index is greater than 70%, the oil content index is greater than 5% and the water-soluble hydrocarbon index is greater than 10%, the reservoir is an oil-water mixed layer; when the movable water index is greater than 70%, the oil content index is less than 5% and the water-soluble hydrocarbon index is greater than or equal to 0, the reservoir is a water layer; The movable water index is calculated according to the following formula: KDS=(Sg-Sy) / Sg*100% (1) In formula (1), KDS is the movable water index, Sy is the movable oil signal area, and Sg is the movable dry sweep signal area; The oil content index is calculated according to the following formula: In formulas (4) to (5), e i is the movable oil saturation, HYZ is the oil content index, X is the natural logarithm, X i is the natural logarithm of a single well, X min is the minimum natural logarithm of the region, X max is the maximum natural logarithm of the region.
2. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 1 is characterized in that The NMR data include the movable oil signal intensity, the movable dry sweep signal intensity, the relaxation time corresponding to the T2 cutoff value, the relaxation time at the end of the NMR signal, and the movable oil saturation.
3. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 1 or 2 is characterized in that The movable oil signal area is calculated using the following formula: In formula (2), Sy is the movable oil signal area; y is the movable oil signal intensity, unit: n / a; is the relaxation time corresponding to the T2 cutoff value, unit: ms; It is the relaxation time at the end of the NMR signal, unit: ms.
4. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 1 or 2 is characterized in that The movable dry sweep signal area is calculated by the following formula: In formula (3), Sg is the movable dry sweep signal area, g is the movable dry sweep signal intensity, unit: n / a; is the relaxation time corresponding to the T2 cutoff value, unit: ms; It is the relaxation time at the end of the NMR signal, unit: ms.
5. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 3 is characterized in that The movable dry sweep signal area is calculated by the following formula: In formula (3), Sg is the movable dry sweep signal area, g is the movable dry sweep signal intensity, unit: n / a; is the relaxation time corresponding to the T2 cutoff value, unit: ms; It is the relaxation time at the end of the NMR signal, unit: ms.
6. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 3 is characterized in that The microscopic fluorescence thin-section data include the percentage of luminescent area of water-soluble hydrocarbons and the percentage of luminescent area of fluids.
7. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 4 is characterized in that The microscopic fluorescence thin-section data include the percentage of luminescent area of water-soluble hydrocarbons and the percentage of luminescent area of fluids.
8. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 5 is characterized in that The microscopic fluorescence thin-section data include the percentage of luminescent area of water-soluble hydrocarbons and the percentage of luminescent area of fluids.
9. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 6 is characterized in that The water-soluble hydrocarbon index is the ratio of the luminescent area of water-soluble hydrocarbons to the luminescent area of fluid multiplied by 100%.
10. The reservoir water content evaluation model constructed by the nuclear magnetic resonance and microfluorescence fusion technology according to claim 7 is characterized in that The water-soluble hydrocarbon index is the ratio of the luminescent area of water-soluble hydrocarbons to the luminescent area of fluid multiplied by 100%.