CN110687613B - Method for continuously characterizing relative wettability index of shale oil reservoir - Google Patents

Method for continuously characterizing relative wettability index of shale oil reservoir Download PDF

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CN110687613B
CN110687613B CN201910914016.6A CN201910914016A CN110687613B CN 110687613 B CN110687613 B CN 110687613B CN 201910914016 A CN201910914016 A CN 201910914016A CN 110687613 B CN110687613 B CN 110687613B
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霍进
宋永�
毛新军
支东明
孙中春
贾希玉
王伟
王振林
张妮
牟立伟
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Petrochina Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/18Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
    • G01V3/32Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with electron or nuclear magnetic resonance
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N13/00Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
    • G01N13/04Investigating osmotic effects
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N24/00Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects
    • G01N24/08Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects by using nuclear magnetic resonance
    • G01N24/081Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00Investigating or analyzing materials by the use of thermal means
    • G01N25/14Investigating or analyzing materials by the use of thermal means by using distillation, extraction, sublimation, condensation, freezing, or crystallisation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/38Processing data, e.g. for analysis, for interpretation, for correction

Abstract

The invention provides a method for continuously characterizing a relative wettability index of a shale oil reservoir, which comprises the following steps: step S1, drilling, closing and coring are carried out on the shale oil dessert section to obtain a rock core sample which is full of oil and well stored in a fluid state; step S2, performing nuclear magnetic resonance logging on the shale oil dessert section to obtain a nuclear magnetic resonance logging spectrum; step S3, performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement, the self-priming relative wettability index and the distillation saturation, and calculating the threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j1(ii) a Step S4, calculating the upper limit value T of the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j2(ii) a Step S5, logging the spectrum according to the nuclear magnetic resonance, the threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously. The invention provides a brand new technical means for the full-section evaluation of the wettability of the shale oil reservoir.

Description

Method for continuously characterizing relative wettability index of shale oil reservoir
Technical Field
The invention relates to the technical field of shale oil exploration and development, in particular to a method for continuously representing a shale oil reservoir relative wettability index.
Background
The shale oil (gas) revolution in north america has changed the world's oil and gas supply pattern. The shale oil (gas) resource is rich in the global range, and a brand new and important field is provided for oil gas exploration and development. The wettability of the shale oil reservoir has a large influence on the mobility of shale oil, thereby affecting the exploitation mode of shale oil. The wettability index of an oil reservoir is generally obtained by core analysis, the wettability data obtained by the method is limited by the core position of a well, the cost for obtaining the wettability index is relatively high, and the analysis data is discrete and cannot represent the wettability characteristics of the whole well profile. The logging information has the characteristics of continuity and high resolution, the wettability of the shale oil reservoir is continuously represented by the logging information, the wettability of the reservoir with a full section is analyzed, and the method has great significance for shale oil exploration and development.
Experimental research shows that the shale oil reservoir is generally mixed wet or oil wet, and is characterized by oleophilic oil-containing pores and hydrophilic surface wettability compared with the conventional oil reservoir due to buoyancy.
Experimental research shows that, different from a conventional reservoir, the shale oil reservoir has no invasion of drilling fluid, and the measurement range of nuclear magnetic resonance is basically an undisturbed formation. For shale oil reservoirs, the response characteristic of nmr is the sum of the contributions of surface relaxation of adsorbed water, surface relaxation of oil adsorbed by oleophilic pores, and volume relaxation of free oil.
That is, the prior art has a problem in that the cost for characterizing the wettability index is high.
Disclosure of Invention
The invention mainly aims to provide a method for continuously characterizing a relative wettability index of a shale oil reservoir, so as to solve the problem of high cost of characterizing the wettability index in the prior art.
To achieve the above object, according to one aspect of the present invention, there is provided a method of continuously characterizing a shale oil reservoir relative wettability index, comprising: step S1, drilling, closing and coring are carried out on the shale oil dessert section to obtain a rock core sample which is full of oil and well stored in a fluid state; step S2, performing nuclear magnetic resonance logging on the shale oil dessert section to obtain a nuclear magnetic resonance logging spectrum; step S3, performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement result, the self-priming relative wettability index and the distillation saturation, and calculating the threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j1(ii) a Step S4, calculating the upper limit value T of the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j2(ii) a Step S5, logging the spectrum according to the nuclear magnetic resonance, the threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously.
Further, step S3 further includes: step S31, horizontally drilling a plurality of 1-inch plunger samples on the core sample, dividing each plunger sample into two parallel analysis samples, wherein one parallel analysis sample is an experimental sample for nuclear magnetic resonance measurement and distillation saturation measurement, and the other parallel analysis sample is a control sample for relative wettability measurement by a self-priming method; and step S32, performing nuclear magnetic resonance measurement on the experimental sample, obtaining a nuclear magnetic resonance T2 spectrum, and determining nuclear magnetic porosity.
Further, step S3 includes step S33, selecting an experimental sample having a nmr porosity of 0.08 or more and 0.16 or less and a peak in an nmr T2 spectrum as a selected sample, and performing a self-priming relative wettability measurement on a control sample in the same plunger sample as the selected sample.
Further, the step S3 includes a step S34 of performing distillation saturation measurement on the experimental samples with different wetting characteristics and completed nmr measurement to obtain the water saturation of the core sample.
Further, the step S3 includes a step S35 of dividing the control sample into a plurality of wetting samples according to the measurement result after the relative wettability measurement by the self-priming method, wherein the plurality of wetting samples at least include a neutral wetting sample and a weak oil wetting sample, selecting a nuclear magnetic resonance T2 spectrum of the neutral wetting sample or the weak oil wetting sample, accumulating the porosity from left to right, determining a T2 transverse relaxation time corresponding to the water saturation of the core sample, and the transverse relaxation time is used as a T2 threshold value T between the volume of adsorbed water and the volume of adsorbed oil2j1
Further, in step S33, the relative wettability index calculation formula of the self-priming relative wettability measurement is:
IA=Iw+Io equation 1
Wherein, IARelative wetting index, I, measured for self-priming methodwAs a displacement ratio with water, IoThe displacement ratio is oil displacement ratio.
Further, the multi-stage wetted samples are based on the relative wettability index IAIs divided by the size of (A), relative wettability index IAA relative wettability index I of-1 or more and 1 or less as measured by a self-priming methodAWhen the sample is more than or equal to-1 and less than or equal to-0.7, the multi-stage wetting sample is wetted by strong oil to be used as a strong oil wetting sample; relative wettability index I when measured by the self-priming methodAWhen the sample is more than or equal to-0.7 and less than or equal to-0.3, the multi-stage wetting sample is oil-wet and is used as an oil-wet sample; when coming fromRelative wettability index I measured by pipettingAWhen the sample is more than or equal to-0.3 and less than or equal to-0.1, the multistage wetting sample is wetted by weak oil to be used as a weak oil wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to-0.1 and less than or equal to 0.1, the multi-stage wetting sample is neutral wetting to be used as a neutral wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to 0.1 and less than or equal to 0.3, the multistage wetting sample is wetted by weak water to be used as a weak water wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to 0.3 and less than or equal to 0.7, the multi-stage wetting sample is wetted by water to serve as a water wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is 0.7 or more and 1 or less, the multi-stage wet sample is strongly wetted with water to be used as a strongly wetted sample.
Further, in step S33, the peak includes at least one of an adsorbed water peak, an adsorption peak, and a volume relaxation peak.
Further, step S4 further includes: step S41, according to the nuclear magnetic resonance T2 spectrum and the T2 threshold value T between the volume of the adsorbed water and the volume of the adsorbed oil2j1Calculating the volume of the absorbed water:
Figure BDA0002215542560000031
wherein, VAdsorbed waterThe volume of the absorbed water calculated by applying a nuclear magnetic resonance T2 spectrum is dimensionless and decimal; piPorosity components corresponding to the nuclear magnetic resonance T2 spectrum, dimensionless and decimal; t is2j1Is the T2 threshold value between the volume of adsorbed water and the volume of adsorbed oil;
step S42, calculating adsorbed oil volume from the measured wettability index:
Figure BDA0002215542560000032
wherein, VAdsorbed waterThe volume of the absorbed water calculated by applying a nuclear magnetic resonance T2 spectrum is dimensionless and decimal; i isrFor relative wetting of core measurementsWetness index, dimensionless, decimal;
step S43, from T2j1And starting to accumulate the nuclear magnetic resonance T2 spectrum of the rock core sample rightwards until the calculated adsorbed oil volume is equal to the adsorbed oil volume in the step S42, wherein the T2 value corresponding to the nuclear magnetic resonance T2 spectrum of the rock core is the upper limit T of the calculation of the adsorbed oil volume2j2
Further, step S5 includes:
Figure BDA0002215542560000033
Figure BDA0002215542560000034
Figure BDA0002215542560000035
wherein, VAdsorbed water(h) The volume of the absorbed water is calculated by applying logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; vAdsorption oil(h) The volume of the adsorbed oil is calculated by applying logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; i isr(h) The relative wettability index calculated by the common logging nuclear magnetic spectrum with the depth of h point is dimensionless and decimal.
By applying the technical scheme of the invention, the method for continuously representing the relative wettability index of the shale oil reservoir comprises the following steps: step S1, drilling, closing and coring are carried out on the shale oil dessert section to obtain a rock core sample which is full of oil and well stored in a fluid state; step S2, performing nuclear magnetic resonance logging on the shale oil dessert section to obtain a nuclear magnetic resonance logging spectrum; step S3, performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement result, the self-priming relative wettability index and the distillation saturation, and calculating the threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j1(ii) a Step S4, calculating the upper limit value T of the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j2(ii) a Step S5, according to the nuclear magnetic resonanceWell spectrum, threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously.
And drilling and closing to core in the shale oil dessert section to obtain core samples which are full of oil and complete in fluid state, so that the measured samples are all from the oil reservoir, and the accuracy of the measured data is improved. And performing nuclear magnetic resonance logging on the shale oil dessert section to determine the nuclear magnetic resonance logging spectrum of the environment where the core sample is located. And performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement result, the self-priming relative wettability index and the distillation saturation, and determining a threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil2j1And an upper limit value T of the volume of adsorbed oil2j2Then logging the spectrum according to the nuclear magnetic resonance, the threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously. The method realizes the quantitative and continuous characterization of the shale oil reservoir relative wettability index logging, and provides a brand new technical means for the full-section evaluation of the shale oil reservoir wettability. Meanwhile, the wettability characteristics of the whole drilling profile can be known by adopting one-time drilling coring, so that the times of drilling coring are greatly reduced, and the measurement cost is further reduced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 shows a flow chart of a method of continuously characterizing the relative wettability index of a shale oil reservoir in accordance with an alternative embodiment of the present invention; and
FIG. 2 shows a nuclear magnetic resonance log spectrum of an alternative embodiment of the invention;
FIG. 3 shows a nuclear magnetic resonance T2 spectrum at formation temperature for a sample (porosity 18.5%, oil saturation 78%, relative wettability index-0.12) of an alternative embodiment of the invention;
FIG. 4 shows a nuclear magnetic resonance T2 spectrum at formation temperature for a sample (porosity 19.0%, oil saturation 87%, relative wettability index-0.39) of an alternative embodiment of the invention;
FIG. 5 shows a nuclear magnetic resonance T2 spectrum at formation temperature for a sample (porosity 18.5%, oil saturation 98.6%, relative wettability index-0.89) of an alternative embodiment of the invention;
FIG. 6 shows a nuclear magnetic resonance T2 spectrum at formation temperature for a sample (porosity 16.4%, oil saturation 99.4%, relative wettability index-0.97) of an alternative embodiment of the invention;
figure 7 shows a graph of the relative wettability index results from an alternative embodiment of the present invention using a method of continuously characterizing the relative wettability index of a shale oil reservoir.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
In the present invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.
In order to solve the problem of high cost of representing the wettability index in the prior art, the invention provides a method for continuously representing the relative wettability index of a shale oil reservoir.
As shown in fig. 1, a method of continuously characterizing the relative wettability index of a shale oil reservoir comprises: step S1, drilling, closing and coring are carried out on the shale oil dessert section to obtainA core sample which is saturated with oil and well preserved in a fluid state; step S2, performing nuclear magnetic resonance logging on the shale oil dessert section to obtain a nuclear magnetic resonance logging spectrum; step S3, performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement result, the self-priming relative wettability index and the distillation saturation, and calculating the threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j1(ii) a Step S4, calculating the upper limit value T of the volume of the adsorbed oil according to the nuclear magnetic resonance spectrum2j2(ii) a Step S5, logging the spectrum according to the nuclear magnetic resonance, the threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously.
And drilling and closing to core in the shale oil dessert section to obtain core samples which are full of oil and complete in fluid state, so that the measured samples are all from the oil reservoir, and the accuracy of the measured data is improved. And performing nuclear magnetic resonance logging on the shale oil dessert section to determine the nuclear magnetic resonance logging spectrum of the environment where the core sample is located. And performing nuclear magnetic resonance measurement, self-priming relative wettability measurement and distillation saturation measurement on the rock core sample, determining a nuclear magnetic resonance spectrum according to the nuclear magnetic resonance measurement result, the self-priming relative wettability index and the distillation saturation, and determining a threshold value T of the volume of the adsorbed water and the volume of the adsorbed oil2j1And an upper limit value T of the volume of adsorbed oil2j2Then logging the spectrum according to the nuclear magnetic resonance, the threshold value T2j1And an upper limit value T2j2The relative wettability index for each depth point is calculated continuously. The method realizes the quantitative and continuous characterization of the shale oil reservoir relative wettability index logging, and provides a brand new technical means for the full-section evaluation of the shale oil reservoir wettability. Meanwhile, the wettability characteristics of the whole drilling profile can be known by adopting one-time drilling coring, so that the times of drilling coring are greatly reduced, and the measurement cost is further reduced.
It should be noted that the shale oil dessert segment refers to a layer segment of shale that is enriched in crude oil and relatively easy to recover. The well-preserved fluid state refers to the core which is not volatilized or has small volatilization amount of oil in the process that the core which is saturated with the oil goes from the underground to the ground.
Specifically, step S3 further includes: step S31, horizontally drilling a plurality of 1-inch plunger samples on the core sample, dividing each plunger sample into two parallel analysis samples, wherein one parallel analysis sample is an experimental sample for nuclear magnetic resonance measurement and distillation saturation measurement, and the other parallel analysis sample is a control sample for relative wettability measurement by a self-priming method; step S32, performing nuclear magnetic resonance measurement on the experimental sample, obtaining a nuclear magnetic resonance T2 spectrum, and determining nuclear magnetic porosity; step S33, selecting an experimental sample which satisfies that the nuclear magnetic porosity is more than or equal to 0.08 and less than or equal to 0.16 and the nuclear magnetic resonance T2 spectrum has a peak as a selected sample, and performing relative wettability measurement by a self-priming method with a control sample which is in the same plunger sample with the selected sample; step S34, carrying out distillation saturation measurement on the experimental samples with different wetting characteristics and completing nuclear magnetic resonance measurement to obtain the water saturation of the core sample; step S35, after the relative wettability measurement by the self-priming method, dividing the control sample into a plurality of levels of wetting samples according to the measurement result, wherein the plurality of levels of wetting samples at least comprise neutral wetting samples and weak oil wetting samples, selecting a nuclear magnetic resonance T2 spectrum of the neutral wetting samples or the weak oil wetting samples, accumulating the porosity from left to right, determining the transverse relaxation time of the porosity percentage equal to the T2 corresponding to the water saturation of the rock core sample, and the transverse relaxation time is used as the T2 threshold value T between the volume of the adsorbed water and the volume of the adsorbed oil2j1
The porosity is the ratio of the volume of the rock sample pore space to the volume of the rock sample; the percent porosity is the ratio of the pore volume of water to the total pore volume of the rock sample.
A plurality of 1-inch plunger samples were divided into two equal parts to serve as an experimental sample and a control sample, so that the control sample was used to know the wettability of each sample in the experimental sample, and the experimental sample was not contaminated, thereby increasing the accuracy of the nuclear magnetic resonance T2 spectrum obtained by the experimental sample. By accumulating the porosity of the nuclear magnetic resonance T2 spectrum, when the accumulated data is equal to the water saturation of the core sample, the transverse relaxation time corresponding to the nuclear magnetic resonance T2 spectrum is the adsorbed water volume and the adsorbed oil volumeT2 limit value T in between2j1
In step S33, the relative wettability index calculation formula of the self-priming relative wettability measurement is:
IA=Iw+Io equation 1
Wherein, IARelative wetting index, I, measured for self-priming methodwAs a displacement ratio with water, IoThe displacement ratio is oil displacement ratio.
The water displacement ratio is the ratio of the volume of oil displaced by automatic imbibition to the total volume of oil displaced by water imbibition and forced displacement; the oil displacement ratio is the ratio of the volume of water displaced by automatic oil imbibition to the total volume of water displaced by oil imbibition and forced displacement.
In particular, the multi-stage wetting samples are based on the relative wettability index IAIs divided by the size of (A), relative wettability index IAA relative wettability index I of-1 or more and 1 or less as measured by a self-priming methodAWhen the sample is more than or equal to-1 and less than or equal to-0.7, the multi-stage wetting sample is wetted by strong oil to be used as a strong oil wetting sample; relative wettability index I when measured by the self-priming methodAWhen the sample is more than or equal to-0.7 and less than or equal to-0.3, the multi-stage wetting sample is oil-wet and is used as an oil-wet sample; relative wettability index I when measured by the self-priming methodAWhen the sample is more than or equal to-0.3 and less than or equal to-0.1, the multistage wetting sample is wetted by weak oil to be used as a weak oil wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to-0.1 and less than or equal to 0.1, the multi-stage wetting sample is neutral wetting to be used as a neutral wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to 0.1 and less than or equal to 0.3, the multistage wetting sample is wetted by weak water to be used as a weak water wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is more than or equal to 0.3 and less than or equal to 0.7, the multi-stage wetting sample is wetted by water to serve as a water wetting sample; relative wettability index I when measured by the self-priming methodAWhen the concentration is 0.7 or more and 1 or less, the multi-stage wet sample is strongly wetted with water to be used as a strongly wetted sample. In step S33, I is selectedAMore than or equal to-0.3 and less than or equal toThe porosity in the NMR T2 spectrum of the 0.1 test sample was accumulated to determine the T2 limit T between the adsorbed water and the adsorbed oil2j1
In step S33, the peak includes at least one of an adsorbed water peak, an adsorption peak, and a volume relaxation peak. The self-absorption method relative wettability index determination of a control sample with obvious absorption peak, absorption oil peak and volume relaxation peak is selected in the application. Of course, a control sample with a significant volume relaxation peak can be selected for the relative wettability index determination by the self-priming method.
Step S4 further includes: step S41, according to the nuclear magnetic resonance T2 spectrum and the T2 threshold value T between the volume of the adsorbed water and the volume of the adsorbed oil2j1Calculating the volume of the absorbed water:
Figure BDA0002215542560000071
wherein, VAdsorbed waterThe volume of the absorbed water calculated by applying a nuclear magnetic resonance T2 spectrum is dimensionless and decimal; piPorosity components corresponding to the nuclear magnetic resonance T2 spectrum, dimensionless and decimal; t is2j1Is the T2 threshold value between the volume of adsorbed water and the volume of adsorbed oil;
step S42, calculating adsorbed oil volume from the measured wettability index:
Figure BDA0002215542560000072
wherein, VAdsorbed waterThe volume of the absorbed water calculated by applying a nuclear magnetic resonance T2 spectrum is dimensionless and decimal; i isrThe relative wettability index, dimensionless, decimal, of the core measurement;
step S43, from T2j1And starting to accumulate the nuclear magnetic resonance T2 spectrum of the rock core sample rightwards until the calculated adsorbed oil volume is equal to the adsorbed oil volume in the step S42, wherein the T2 value corresponding to the nuclear magnetic resonance T2 spectrum of the rock core is the upper limit T of the calculation of the adsorbed oil volume2j2
Further, step S5 includes:
Figure BDA0002215542560000073
Figure BDA0002215542560000074
Figure BDA0002215542560000075
wherein, VAdsorbed water(h) The volume of the absorbed water is calculated by applying logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; vAdsorption oil(h) The volume of the adsorbed oil is calculated by applying logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; i isr(h) The relative wettability index calculated by the common logging nuclear magnetic spectrum with the depth of h point is dimensionless and decimal.
Taking a specific example as an example, four samples were taken, sample 1 having a nuclear magnetic porosity of 18.5%, a water saturation of 22.0% and a measured relative wettability index of-0.12, sample 2 having a nuclear magnetic porosity of 19.0%, a water saturation of 13.0% and a measured relative wettability index of-0.39, sample 3 having a nuclear magnetic porosity of 18.5%, a water saturation of 1.4% and a measured relative wettability index of-0.89, sample 4 having a nuclear magnetic porosity of 16.4%, a water saturation of 0.6% and a measured relative wettability index of-0.97, sample 1 having a weak oil wetness and sample 2 having an oil wetness were taken and subjected to nuclear magnetic spectrum measurements to obtain a nuclear magnetic resonance T2 spectrum (see FIG. 3) of sample 1 and a nuclear magnetic resonance T2 spectrum (see FIG. 4) of sample 2, the nuclear magnetic resonance T2 spectrum of sample 1 and the nuclear magnetic resonance T2 spectrum of sample 2 were accumulated in a left-to-right direction, when the percentage of porosity is equal to the transverse relaxation time corresponding to the water saturation of the rock core sample, the transverse relaxation time obtained by the sample 1 is 3.4ms, the transverse relaxation time obtained by the sample 2 is 3.3ms, and then the threshold value T of the adsorbed water volume and the adsorbed oil volume is determined2j1Is 3.3 ms.
According to the limit value T of the volume of the adsorbed water and the volume of the adsorbed oil2j1The volume of water adsorbed was calculated,
Figure BDA0002215542560000081
in this example the aqueous volume of sample 1 was 0.041, the aqueous volume of sample 2 was 0.025, the aqueous volume of sample 3 was 0.0026 and the aqueous volume of sample 4 was 0.001.
Calculating the volume of the adsorbed oil according to the volume of the adsorbed water and the relative wettability index,
Figure BDA0002215542560000082
since samples 3 and 4 are strong oil wet and have low water saturation, and are used for calculating the adsorbed oil content with a large error, the adsorbed oil volume is calculated by using samples 1 and 2, and the calculation results are that sample 1 is 0.052 and sample 2 is 0.057 respectively. The nmr T2 spectrum of sample 1 was accumulated to the right starting at 3.3ms until the calculated adsorbed oil volume was 0.052, at which time the transverse relaxation time of the nmr T2 spectrum of sample 1 was 32 ms. The nmr T2 spectrum of sample 2 was accumulated in the same way and the transverse relaxation time obtained was 32.3 ms. The relative wettability index obtained by accumulating the nuclear magnetic resonance T2 spectrum of the sample 3 from 3.3ms to 32m is consistent with the experimental result, and the relative wettability index obtained by accumulating the nuclear magnetic resonance T2 spectrum of the sample 4 from 3.3ms to 32ms is consistent with the experimental result. The upper limit value T of the adsorbed oil volume can thus be determined2j2Is 32 ms.
Then according to the limit value T of the volume of the adsorbed water and the volume of the adsorbed oil2j1And an upper limit value T of the volume of adsorbed oil2j2And nuclear magnetic resonance logging data of the well section, and continuously and quantitatively calculating the relative wettability index of the shale oil of the well section, as shown in fig. 7, as can be seen from fig. 7, the change rule of the experimental value and the calculated value is completely consistent, and the numerical value is basically equal.
In addition, V is as defined aboveAdsorbed waterIs the volume of water in a unit volume of the sample, VAdsorption oilRefers to the volume occupied by oil per unit volume of sample. Both are decimals without dimension.
It is to be understood that the above-described embodiments are only a few, but not all, embodiments of the present 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.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. A method for continuously characterizing the relative wettability index of a shale oil reservoir, comprising:
step S1, drilling, closing and coring are carried out on the shale oil dessert section to obtain a rock core sample which is full of oil and well stored in a fluid state;
step S2, performing nuclear magnetic resonance logging on the shale oil dessert section to obtain a nuclear magnetic resonance logging spectrum;
step S3, performing nuclear magnetic resonance measurement, self-absorption relative wettability measurement and distillation saturation measurement on the core sample, and measuring the knot according to the nuclear magnetic resonanceDetermining nuclear magnetic resonance spectrum according to relative wettability index and distillation saturation of fruit and self-absorption method, and calculating threshold value T of volume of adsorbed water and volume of adsorbed oil according to the nuclear magnetic resonance spectrum2j1
The step S3 further includes:
step S31, horizontally drilling a plurality of 1-inch plunger samples on the core sample, dividing each plunger sample into two parallel analysis samples, wherein one parallel analysis sample is an experimental sample for the nuclear magnetic resonance measurement and the distillation saturation measurement, and the other parallel analysis sample is a control sample for the self-priming relative wettability measurement;
step S32, performing nuclear magnetic resonance measurement on the experimental sample, obtaining a nuclear magnetic resonance T2 spectrum, and determining nuclear magnetic porosity;
step S33, selecting the experimental sample which satisfies that the nuclear magnetic porosity is more than or equal to 0.08 and less than or equal to 0.16 and the nuclear magnetic resonance T2 spectrum has a peak as a selected sample, and carrying out the self-priming relative wettability measurement on a control sample which is in the same plunger sample with the selected sample;
step S34, carrying out distillation saturation measurement on the experimental samples with different wetting characteristics and completing the nuclear magnetic resonance measurement to obtain the water saturation of the core sample;
step S35, after the self-priming method relative wettability measurement, dividing the control sample into a plurality of stages of wetting samples according to the measurement result, wherein the plurality of stages of wetting samples at least comprise neutral wetting samples and weak oil wetting samples, selecting the nuclear magnetic resonance T2 spectrum of the neutral wetting samples or the weak oil wetting samples, accumulating the porosity from left to right, determining the transverse relaxation time of the nuclear magnetic resonance T2 spectrum with the porosity percentage equal to the water saturation of the rock core sample, and the transverse relaxation time is used as the T2 threshold value T between the volume of the adsorbed water and the volume of the adsorbed oil2j1
Step S4, calculating the upper limit value T of the volume of the adsorption oil according to the nuclear magnetic resonance spectrum2j2
From T2j1And starting to accumulate the nuclear magnetic resonance T2 spectrum of the core sample rightwards until the calculated adsorbed oil volume is equal to the adsorbed oil volume calculated according to the measured wettability index, wherein the T2 value corresponding to the nuclear magnetic resonance T2 spectrum of the core is the calculation upper limit T of the adsorbed oil volume2j2
Step S5, according to the nuclear magnetic resonance logging spectrum and the threshold value T2j1And the upper limit value T2j2The relative wettability index for each depth point is calculated continuously.
2. The method for continuously characterizing the relative wettability index of a shale oil reservoir as claimed in claim 1, wherein in said step S33, said relative wettability index calculation formula of said self-priming relative wettability measurement is:
IA=Iw+Ioequation 1
Wherein, IARelative wetting index, I, measured for self-priming methodwAs a displacement ratio with water, IoThe displacement ratio is oil displacement ratio.
3. Method for continuously characterizing the relative wettability index of shale oil reservoirs in accordance with claim 2, wherein said multi-stage wetting sample is according to relative wettability index IAIs divided by the size of the relative wettability index IAIs greater than or equal to-1 and less than or equal to 1,
when the relative wettability index I is measured by the self-priming methodAWhen the sample is larger than or equal to-1 and smaller than-0.7, the multistage wetting sample is wetted by strong oil to serve as a strong oil wetting sample;
when the relative wettability index I is measured by the self-priming methodAWhen the sample is more than or equal to-0.7 and less than-0.3, the multistage wetting sample is oil-wet and is used as an oil-wet sample;
when the relative wettability index I is measured by the self-priming methodAWhen the sample is more than or equal to-0.3 and less than-0.1, the multistage wetting sample is wetted by weak oil to serve as the weak oil wetting sample;
when measured by the self-priming methodRelative wettability index IAWhen the concentration is more than or equal to-0.1 and less than or equal to 0.1, the multistage wetting sample is neutral wetting to be used as the neutral wetting sample;
when the relative wettability index I is measured by the self-priming methodAWhen the concentration of the multi-stage wetting sample is more than 0.1 and less than or equal to 0.3, the multi-stage wetting sample is wetted by weak water to be used as a weak water wetting sample;
when the relative wettability index I is measured by the self-priming methodAWhen the concentration is more than 0.3 and less than or equal to 0.7, the multistage wetting sample is wetted by water to serve as a water wetting sample;
when the relative wettability index I is measured by the self-priming methodAAnd when the concentration is more than 0.7 and less than or equal to 1, the multistage wetting sample is wetted by strong water to be used as a strong water wetting sample.
4. The method for continuously characterizing the relative wettability index of a shale oil reservoir according to claim 1, wherein in step S33, said peaks include at least one of an adsorbed water peak, an adsorption peak and a volume relaxation peak.
5. The method for continuously characterizing the relative wettability index of shale oil reservoirs according to claim 1, wherein said step S4 further comprises:
step S41, according to the nuclear magnetic resonance T2 spectrum and the T2 threshold value T between the volume of the adsorption water and the volume of the adsorption oil2j1Calculating the volume of the adsorbed water:
Figure FDA0002512935800000021
wherein, VAdsorbed waterThe volume of the adsorbed water calculated by applying the nuclear magnetic resonance T2 spectrum is dimensionless and decimal; piIs a porosity component, dimensionless, decimal, corresponding to the nuclear magnetic resonance T2 spectrum; t is2j1Is a threshold value between the adsorbed water volume and the adsorbed oil volume;
step S42, calculating the adsorbed oil volume from the measured wettability index:
Figure FDA0002512935800000031
wherein, VAdsorption oilThe volume, dimensionless, decimal fraction of the adsorbed oil calculated for the application of the nuclear magnetic resonance T2 spectrum; i isrThe relative wettability index, dimensionless, decimal, of the core measurements.
6. The method for continuously characterizing the relative wettability index of shale oil reservoirs according to claim 5, wherein said step S5 comprises:
Figure FDA0002512935800000032
Figure FDA0002512935800000033
Figure FDA0002512935800000034
wherein, VAdsorbed water(h) The volume of the adsorbed water is calculated by applying a logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; vAdsorption oil(h) The volume of the adsorbed oil is calculated by applying logging nuclear magnetic spectrum with the depth of h point, and is dimensionless and decimal; i isr(h) The relative wettability index, dimensionless and decimal, calculated by applying the logging nuclear magnetic spectrum for the depth h point; pi(h) The porosity component of the spectrum of nuclear magnetic resonance T2 with the depth h point.
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Publication number Priority date Publication date Assignee Title
CN113138205A (en) * 2020-01-20 2021-07-20 中国石油天然气股份有限公司 Method and system for determining gas-water imbibition condition in porous medium
CN113820249B (en) * 2021-11-22 2022-03-01 中国矿业大学(北京) Device and method for evaluating wettability of sediment based on imbibition nuclear magnetic resonance
CN116223553B (en) * 2023-03-14 2023-11-14 西南石油大学 Shale wettability fine characterization method based on nuclear magnetic resonance

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101196460A (en) * 2007-10-26 2008-06-11 辽河石油勘探局 Appraisement method for rock wettability
CN102834737A (en) * 2009-12-16 2012-12-19 英国石油勘探运作有限公司 Method for measuring rock wettability
CN104246484A (en) * 2012-04-02 2014-12-24 普拉德研究及开发股份有限公司 Methods for determining wettability from NMR
CN106525888A (en) * 2016-09-26 2017-03-22 中国石油天然气股份有限公司 Method and device for testing wettability of tight oil reservoir
CN109030292A (en) * 2018-09-26 2018-12-18 西南石油大学 A kind of new method that tight rock wetability determines
WO2019070548A1 (en) * 2017-10-03 2019-04-11 Schlumberger Technology Corporation Wettability of formations with heavy oil

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8538700B2 (en) * 2010-07-13 2013-09-17 Schlumberger Technology Corporation Method of determining subterranean formation parameters
US9016111B2 (en) * 2011-12-14 2015-04-28 Schlumberger Technology Corporation Methods for determining wettability alteration
US9746576B2 (en) * 2014-05-27 2017-08-29 Baker Hughes Incorporated Wettability estimation using magnetic resonance
US10718701B2 (en) * 2015-05-12 2020-07-21 Schlumberger Technology Corporation NMR based reservoir wettability measurements

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101196460A (en) * 2007-10-26 2008-06-11 辽河石油勘探局 Appraisement method for rock wettability
CN102834737A (en) * 2009-12-16 2012-12-19 英国石油勘探运作有限公司 Method for measuring rock wettability
CN104730587A (en) * 2009-12-16 2015-06-24 英国石油勘探运作有限公司 Method for measuring rock wettability
CN104849765A (en) * 2009-12-16 2015-08-19 英国石油勘探运作有限公司 Method for measuring rock wettability
CN104246484A (en) * 2012-04-02 2014-12-24 普拉德研究及开发股份有限公司 Methods for determining wettability from NMR
CN106525888A (en) * 2016-09-26 2017-03-22 中国石油天然气股份有限公司 Method and device for testing wettability of tight oil reservoir
WO2019070548A1 (en) * 2017-10-03 2019-04-11 Schlumberger Technology Corporation Wettability of formations with heavy oil
CN109030292A (en) * 2018-09-26 2018-12-18 西南石油大学 A kind of new method that tight rock wetability determines

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
NMR wettability indices: Effect of OBM on wettability and NMR responses;J. Chen,等;《Journal of Petroleum Science and Engineering》;20061231;第161-171页 *
WETTABILITY AS A FUNCTION OF PORE SIZE BY NMR;Ahmed S. Al-Muthana,等;《SCA》;20121231;第1-12页 *
核磁共振法确定润湿性指数;汪先珍,等;《国外油田工程》;20070731;第20-27页 *
致密油储层核磁共振测井响应机理研究;赵培强,等;《地球物理学报》;20160531;第1927-1937页 *

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