CN110412111B - Method for performing oil source comparison by using chromium isotope - Google Patents
Method for performing oil source comparison by using chromium isotope Download PDFInfo
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- CN110412111B CN110412111B CN201910608133.XA CN201910608133A CN110412111B CN 110412111 B CN110412111 B CN 110412111B CN 201910608133 A CN201910608133 A CN 201910608133A CN 110412111 B CN110412111 B CN 110412111B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/34—Purifying; Cleaning
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
- G01N2001/2866—Grinding or homogeneising
Abstract
The invention discloses a method for performing oil source comparison by using a chromium isotope. The method comprises the following steps: s100, separating and enriching chromium elements in the crude oil; s200, separating and enriching chromium elements in the source rock; s300, testing and analyzing the content of the chromium element; s400, detecting and analyzing stable isotope composition of chromium; s500, establishing delta through analysis of chromium isotopes in known different deposition environments, different maturity hydrocarbon source rocks and crude oil and hydrocarbon source rocks with different properties53Cr (‰) -oil reservoir type identification index chart; s600, determining the source and cause of the unknown oil source according to the established identification index chart. The method provided by the invention utilizes the chromium isotope to identify the source and cause of the oil gas, and provides technical and theoretical guidance for determining the oil gas exploration target by quickly determining the cause of the oil gas.
Description
Technical Field
The invention belongs to the technical field of oil-gas exploration, and particularly relates to a method for performing oil source comparison by using a chromium isotope.
Background
Organic geochemistry research mainly focuses on composition, structure, origin and evolution of organic matters in geologic bodies, and in the field of oil and gas exploration, especially the comparison between oil and gas causes and oil sources is of great importance, and the research is highly valued because the exploration target evaluation and well location optimization, the scale and distribution rule of oil and gas reservoirs and the like are concerned. The conventional method is to use the indexes such as biological markers, carbon isotopes and the like to determine the cause and source of oil gas, and the method is successfully applied in most areas or oil gas fields. However, in some complex areas, such as the Tarim basin, whether the oil and gas are from the Han-Wu system or the Ordovician system, controversy exists. Therefore, it is necessary to develop a new index system for determining the cause of oil and gas.
Chromium is easily adsorbed and chelated by organic matters, so that chromium is easily enriched in hydrocarbon source rocks, enters oil gas in the hydrocarbon formation process and migrates along with the oil gas, and the chromium has important tracing value along with the processes of organic matter formation, thermal maturity hydrocarbon generation, migration aggregation and the like in deposition. The chromium stable isotope information in the hydrocarbon source rock and the oil gas in different basin areas, different cause types and different thermal evolution stages has certain difference values, and the difference values can be used for judging the cause of the oil gas and guiding the oil gas exploration.
Disclosure of Invention
Based on the above background art, the present invention provides a method for performing oil source comparison by using a chromium isotope. The method fills the gap of identifying the source and the cause of the oil gas by using the chromium isotope at present, and provides technical and theoretical guidance for determining the oil gas exploration target by quickly determining the cause of the oil gas.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for performing oil source comparison by using a chromium isotope, which comprises the following steps:
s100, separating and enriching chromium elements in the crude oil;
s200, separating and enriching chromium elements in the source rock;
s300, testing and analyzing the content of the chromium element;
s400, detecting and analyzing stable isotope composition of chromium;
s500, establishing delta through analysis of chromium isotopes in known different deposition environments, different maturity hydrocarbon source rocks and crude oil and hydrocarbon source rocks with different properties53Cr (‰) -oil reservoir type identification index chart;
the mass fractionation of chromium is that chromium isotopes with different mass numbers are separated and enriched in different reactants in the oxidation-reduction reaction; non-mass fractionation is the fractionation of chromium isotopes in some reactions, largely unaffected by mass factors, but related to the charge energy outside the isotope core, a common feature of high mass numbers of isotopes such as chromium.
S600, determining the source and the cause of the unknown oil source according to the established identification index chart, and guiding exploration deployment.
In the above methods, the source rock and crude oil are respectively from oil field cored well core or peripheral outcrop rock samples, petroleum samples of normal production wells, including crude oil, rock samples, etc. of different cause types and different maturity, and of different properties.
Preferably, said delta53Cr (‰) -oil deposit type identification index plate, delta of coal crude oil53Cr (thousandths) range of 0.12 to 0.21 thousandths, delta of coal-series hydrocarbon source rock53Cr (mill) range is 0.09-0.26 per mill, delta of sea phase crude oil53Cr (‰) range is 0.37-0.47 ‰, and delta of marine hydrocarbon source rock53Cr (thousandths) range is 0.32-0.66 thousandths, delta of continental-phase crude oil53Cr (‰) range is-0.13 ‰ -0.06 ‰, and delta of continental-phase hydrocarbon source rock53The range of Cr (‰) is-0.22 ‰ -0.08 ‰. The following is a detailed description of each step:
s100, separating and enriching chromium elements in the crude oil.
Preferably, S100 specifically includes:
s110, preparing a crude oil sample;
s120, separating and purifying chromium in the crude oil sample.
Further preferably, the preparation of the S110 crude oil sample comprises:
s111, taking fresh crude oil, sequentially adding petroleum ether and ethanol for mixing and dissolving, and heating to obtain a primary sample; wherein, petroleum ether and ethanol are organic solvents with good effect of dissolving organic matters in crude oil.
Preferably, the proportions of crude oil, petroleum ether and ethanol are: (6-8 g): 14-16 mL: 14-16 mL. More preferably (6-8 g): 15mL of: 15 mL.
Preferably, the heating temperature is 75-85 ℃ and the heating time is 11-13 hours. More preferably, the heating is carried out at a temperature of 80 ℃ for a period of 12 hours.
For example, in the embodiment of the present invention, the step specifically includes:
taking about 20g of a fresh crude oil sample from an oil outlet well head of a production well site; weighing 6-8 g of fresh crude oil in a quartz beaker, adding 15mL of petroleum ether, shaking up to mix the crude oil and the petroleum ether basically, adding 15mL of absolute ethyl alcohol, and heating for 12 hours at 80 ℃ on an electric hot plate after shaking up.
And S112, weighing the fresh crude oil again, and repeating the process of S111.
S113, standing the primary samples prepared twice at normal temperature, respectively extracting upper oil samples, mixing, adding absolute ethyl alcohol, shaking up, and heating to prepare a crude oil sample to be tested.
Preferably, the mixture is kept still for 22-24 hours and heated at 60-70 ℃ for 16-18 hours. More preferably, the mixture is left to stand for 24 hours and heated at 60 ℃ for 18 hours.
The reason why the mixing is carried out in two times in this example is to allow the organic component to be sufficiently dissolved and to shorten the heating time.
Further preferably, the separation and purification of the chromium element in the S120 crude oil sample comprises:
1) digesting a crude oil sample;
2) dissolving the digested sample in HNO3And HF, heating for reaction until the sample is completely dissolved; evaporating to dryness to form wet salt after the reaction is finished, and then using HNO3Removing redundant HF, finally adding HCl, and evaporating to dryness to obtain powder;
3) uniformly mixing the powder with lithium tetraborate and lithium bromide, and then putting the mixture into a muffle furnace for ashing;
4) adding HNO3Putting the sample into a Teflon cup, adding the heated sample, covering the Teflon cup with a cover, and uniformly stirring for reaction to obtain a Cr sample to be subjected to column separation;
5) using AG1X8 cation resin with 200 meshes and 300 meshes to separate and purify a Cr sample, using 6mol/L HCl as a medium to separate chromium element, evaporating the purified chromium solution to dryness, and converting the chromium solution into 2 percent HNO3Medium to be tested. Conversion to 2% HNO3The medium is specifically as follows: adding 8mol/L HNO3About 20. mu.L of sample was converted to 2% HNO3A medium; conversion of the sample to 2% HNO3The medium is used to meet the acidic medium requirement of instrument test.
Preferably, the digestion solvent is dichloromethane, and the digestion reagent is HNO3-H2O2And (4) digesting the system.
In S120, the crude oil chromium element is separated by dissolving a sample, CH, by using an organic solvent dichloromethane2Cl2Can fully dissolve petroleum, make each component in the crude oil disperse uniformly, fully contact with a digestion reagent to improve the oxidation efficiency, obtain a monitoring result with better repeatability, and select HNO as the digestion reagent3-H2O2Digestion system to remove H from crude oil2S and organic impurities.
For example, S120 in the embodiment of the present invention specifically includes:
1) accurately weighing 1g of crude oil sample in a high-pressure closed digestion tank, and adding 2mL of CH2Cl2Fully dissolving the crude oil, and then adding 5mL of concentrated HNO3-H2O2Digesting the reagent at the high temperature of 200 ℃ for 5min, cooling, using high-purity water to fix the volume to 10mL, and placing the fixed-volume sample in a drying oven at the temperature of 600 ℃ for 24h to remove organic matters.
2) 2mL of HNO was added3And 4mL of HF, covering a cover, dissolving the sample, and putting the sample into an oven to react for 48 hours at 220 ℃; the steps can be repeated until the sample is completely dissolved, the sample is taken out after cooling, and the sample is dried on a heating plate at 200 ℃ until the sample is in a wet salt state; then 2mL of HNO3Removing redundant HF, repeatedly removing the HF for 3 times, finally adding 5mL of 6mol/L HCl, and evaporating to dryness to obtain powder; this step removes impurities from the sample.
3) Putting 7g of lithium tetraborate and 0.02g of lithium bromide into a quartz crucible, pouring the powder into the quartz crucible, uniformly mixing, putting the mixture into a muffle furnace at 1500 ℃, and standing for 15 min; the sample may be ashed, wherein the lithium tetraborate and lithium bromide are fluxing agents to aid in sample dissolution.
4) Putting 100mL of 3mol/L nitric acid into a Teflon cup, adding the heated sample, covering a cover, and uniformly stirring for 2 hours to obtain a Cr sample to be subjected to column separation;
5) separating and purifying the Cr sample by using Bio-Rad AG1X8 cation resin of 200 meshes and 300 meshes, and separating chromium element by using 6mol/L HCl as a mediumSeparating, purifying to obtain chromium solution, evaporating to dryness, and converting into 2% HNO3A medium to be tested; test element content and isotope analysis were waited for S300 and S400.
S200, separating and enriching chromium elements in the source rock.
Preferably, S200 specifically includes:
s210, selecting and crushing a rock sample to obtain sample powder of the hydrocarbon source rock;
s220, separating and purifying chromium element in the sample powder.
Preferably, S210 includes:
s211, selecting a rock sample;
and S212, crushing the sample, and grinding to obtain sample powder.
In the present embodiment, the process of preparing the sample powder at S210 includes:
1) selecting a rock sample: and (4) observing whether the surface of the rock sample is fresh or not and the weathering degree, and taking a photo to describe the information of the sample and inputting the information into a sample table. Wrapping the sample with clean cloth, covering the top and bottom surfaces of the sample with a wood board, hammering the wood board with a steel hammer to break the sample, selecting about 5g of sample particles with fresh four sides, no quartz vein and no wormhole structure after the sample is broken, clamping the sample with a disposable clamp, putting the sample into a sample bag, and recording and taking the number.
2) Sample crushing: selecting two identical grinding tanks, placing one of the grinding tanks into an agate ball, a) adding quartz sand into the grinding tank with the agate ball to cover the agate ball in half, screwing the two grinding tanks, placing the grinding tanks on a sample crusher, fixing the grinding tanks, rotating the grinding tanks at a speed of 1300r/min for 3 minutes, taking down the quartz powder after the rotation is finished, observing whether the inner surfaces of the grinding tanks are clean, and continuing the step if the inner surfaces of the grinding tanks are not clean. b) Clamping a sample in a sample bag by using a disposable pliers, putting the sample into a grinding tank, screwing the sample on a sample crusher, fixing the sample at a speed of 1300r/min, rotating the sample for 3 minutes, taking down the sample powder after the rotation is finished, pouring the sample powder onto disposable paper, wiping the inner surface of the grinding tank and an agate ball by using a disposable paper towel to pour the sample powder out as much as possible, and pouring the sample powder into the sample bag to record a serial number. c) Washing the grinding tank, and repeating the step a) for 2-3 times (for sure to ensure that the inner surface of the grinding tank is clean). Then the next sample crushing work is carried out in sequence.
Preferably, the separation and purification of the chromium element in the S220 sample powder comprises the following steps:
1) adding HCl into the sample powder in a high-pressure digestion tank to perform digestion reaction; after the reaction is finished, centrifugally cleaning the mixture by using deionized water;
2) drying the centrifugally cleaned sample, and grinding into powder;
3) uniformly mixing the powder in the step 2) with lithium tetraborate and lithium bromide, and then putting the mixture into a muffle furnace for ashing; wherein the lithium tetraborate and the lithium bromide are fluxing agents and are helpful for sample dissolution.
4) Adding HNO3Putting the sample into a Teflon cup, adding the heated sample, covering the Teflon cup with a cover, and uniformly stirring for reaction to obtain a Cr sample to be subjected to column separation;
5) using AG1X8 cation resin with 200-300 meshes to separate and purify a Cr sample; firstly, 3mol/L HNO is prepared3The sample is completely dissolved by the solution, and 6mol/L HNO is used3The resin is washed by the solution and deionized water, and then washed by a mixed solution of 0.02mol/L HCl and 0.2mol/L HF to completely react with the same amount of the isotopologue to remove the isotopologue; then 8mol/L of NH is used3Collecting chromium element in the ion exchange resin by using the solution; evaporating to dryness in a 150 deg.C oven, dissolving with concentrated nitric acid and concentrated hydrochloric acid for several times, and dissolving in 0.3mol/L HNO3In solution, to be tested.
In the embodiment of the present invention, the separation and purification of chromium in the S220 sample powder includes:
1) weighing about 10g of sample powder in a 20mL high-pressure digestion tank, adding 20mL of 3mol/L HCl by using a liquid transfer gun, covering a cover, fully reacting, standing for 24h, then washing by using deionized water, putting into a 3200r/min centrifugal machine for centrifugation for ten minutes after washing, and washing at least for 3 times. In this step, HCl is used to dissolve the sample powder, which is washed with water and centrifuged to dissolve it sufficiently.
2) Putting into a 75 ℃ oven for reaction for 12-20h, drying, grinding into powder by a weighing spoon, and weighing 6 g.
3) Putting 5g of lithium tetraborate and 0.01g of lithium bromide into a quartz crucible, pouring the powder, uniformly mixing, putting into a muffle furnace at 1500 ℃, standing for 15min, and ashing the sample, wherein the lithium tetraborate and the lithium bromide are fluxing agents and are beneficial to dissolving the sample.
4) Putting 50mL of 3mol/L nitric acid into a Teflon cup, adding the heated sample, covering a cover, and uniformly stirring for 2 hours to obtain a Cr sample to be subjected to column separation;
5) separating and purifying the Cr sample by using Bio-Rad AG1X8 cation resin of 200 meshes and 300 meshes to separate out chromium, and firstly preparing 3mol/L HNO3The Cr sample is completely dissolved by the solution, and 6mol/L HNO is used3The resin is washed by the solution and deionized water, then washed by a mixed solution of 0.02mol/L HCl and 0.2mol/L HF to remove the same amount of the isoteophil, and then 8mol/L NH is added3Collecting chromium element in ion exchange resin, evaporating to dryness in oven at 150 deg.C, dissolving with concentrated nitric acid and concentrated hydrochloric acid for three times, and dissolving in 0.3mol/L HNO3Solution, to be tested.
And S300, testing and analyzing the content of the chromium element.
Preferably, S300 includes:
1) crucible cleaning and sample digestion: putting the sample into a cleaned crucible, placing the crucible in a 600 ℃ muffle furnace for 24 hours, taking out the crucible, cooling the crucible to room temperature, transferring the crucible to a microwave digestion tank, placing the microwave digestion tank on an electric hot plate, and heating the microwave digestion tank until the sample is completely evaporated to dryness to obtain a sample with chromium content;
2) sample dissolving: placing a sample with chromium content in a high-temperature furnace at 800 ℃ for ashing treatment, adding nitric acid into the treated residue, placing the residue on an electric heating plate, keeping the temperature at 250 ℃, and heating for dissolving; if the turbid matter appears, adding a proper amount of 1mol/L hydrochloric acid to remove;
adding high-purity HCl and high-purity HF, covering and sealing a steel sleeve, and putting the steel sleeve into an oven at 200 ℃ for keeping the temperature for 48 hours; cooling, evaporating to dryness on an electric hot plate, adding high-purity HCl, evaporating to form wet salt, and performing total digestion in 6mol/L hydrochloric acid to make the solution acidic;
the dissolved sample was transferred to a beaker and HCl and HNO were added3Stewing for 2h, and then opening a cover to drive fluorine;
the sample is completely evaporated to dryness and added50Cr-54The total chromium content was determined by pouring the Cr double diluent into a clean beaker and completely evaporating it to dryness. The most used in the prior art for determining the Cr content is the thermal ionization mass spectrometer TIMS.
The test of the content of the chromium element in the embodiment of the invention specifically comprises the following steps:
firstly, crucible cleaning is carried out to prepare for sample digestion:
(1) the interior of the crucible is wiped by alcohol to remove residual organic matter.
(2) The crucible was soaked with detergent for a period of time, the detergent was rinsed clean, and then rinsed 3 times with deionized water.
(3) Placing the crucible in a beaker, adding high-purity water, placing the crucible on an electric hot plate at 120 ℃, keeping the temperature for 48 hours, and then washing the crucible for 3 times by using secondary water. Drying on an electric heating plate for later use.
(4) And putting the sample into a clean crucible, placing the crucible in a 600 ℃ muffle furnace for 24 hours, taking out the crucible, cooling the crucible to room temperature, transferring the crucible into a microwave digestion tank, placing the microwave digestion tank on an electric hot plate, and heating the microwave digestion tank until the sample is completely evaporated to dryness to obtain the sample with chromium content.
After the digestion of the sample is completed, the sample dissolution is carried out:
(1) accurately weighing 5g of a sample with chromium content, placing the sample in a high-temperature furnace at 800 ℃ for ashing treatment, and adding 5mL of nitric acid into the treated residue. Placing on an electric heating plate, keeping the temperature at 250 ℃, and heating for dissolving. If turbidity occurs, adding proper amount of 1mol/L hydrochloric acid to remove.
(2) Adding 5mL of each of high-purity HCl and high-purity HF, covering and sealing a steel sleeve, and putting the mixture into an oven at 200 ℃ for constant temperature for 48 hours. After cooling, the mixture was evaporated to dryness on a hot plate, and 3mL of high purity HCl was added and evaporated to a wet salt state (to remove residual HF). The total digestion was then carried out in 6mol/L hydrochloric acid and the solution was made acidic.
(3) The dissolved sample was transferred to a beaker and 1.5mL HCl and 0.5mL HNO were added3Stewing for 2h, and then opening the cover to drive fluorine.
(4) The sample is completely evaporated to dryness and added50Cr-54The total chromium content was determined by pouring the Cr double diluent into a clean beaker and completely evaporating it to dryness.
S400, detecting and analyzing the stable isotope composition of the chromium.
Preferably, the stable isotope composition of chromium is analyzed in S400 using a multi-receiver inductively coupled plasma mass spectrometer MC-ICP-MS detection.
The test of the content of the chromium element in the embodiment of the invention specifically comprises the following steps:
(1) the cleaned and cut samples were crushed and burned at 200-300 ℃ for 10 hours in double distilled HCl-HF-HNO3Is digested and then subjected to a second digestion in aqua regia.
(2) The Cr sample was purified with a Bio-Rad AG1X8 cationic resin (200-300 mesh), and the purified sample was measured with a double focusing multi-receiver Plasma mass spectrometer Nu Plasma HR manufactured by Nu Instruments. The DSN-100 type film was used to exsolve into the plasma.
(3) Washing the sample with 0.5mol/L nitric acid for 5 min; then, the standard sample is washed by 0.05mol/L nitric acid for 3 min.
(4) The MC-ICP-MS is used for measuring isotopes with high precision, the allomones of various isotopes (iron, molybdenum, nickel and the like) which can cause chromium interference need to be corrected, the chromium is corrected by using thermal ionization, and the measured chromium isotope ratio result is expressed by the thousandth deviation of a sample relative to a standard sample.
S500, establishing delta through analysis of known chromium isotopes in different deposition environments, different maturity of source rocks, and crude oil and natural gas53Cr (mill) -oil reservoir type identification index chart. Establishment of delta53In the process of identifying the index chart of the Cr (‰) -reservoir type, the value range and the boundary value parameter of the chromium isotope ratio of reservoirs with different cause types need to be determined, and the information characteristics of chromium mass fractionation and non-mass fractionation of the reservoirs with different types are summarized.
S600, determining the source and the cause of the unknown oil source according to the established identification index chart, and guiding exploration deployment.
After the method is used for establishing the identification index chart, the source and the cause of oil gas can be determined by carrying out chromium isotope analysis on the crude oil sample of the new well, and subsequent exploration deployment is guided.
Drawings
FIG. 1 shows δ established in accordance with an embodiment of the present invention53Cr (mill) -oil reservoir type identification index chart.
Detailed Description
In order to more clearly illustrate the invention, the invention is further described below in connection with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
The embodiment of the invention is specifically explained by taking a Bohai Bay basin oil reservoir as an example, and the specific method comprises the following steps:
s111, taking about 20g of a fresh crude oil sample from an oil outlet well head of a production well site; weighing 6-8 g of fresh crude oil in a quartz beaker, adding 15mL of petroleum ether, shaking up to mix the crude oil and the petroleum ether basically, adding 15mL of absolute ethyl alcohol, and heating for 12 hours at 80 ℃ on an electric hot plate after shaking up.
And S112, weighing 6-8 g of fresh crude oil in the quartz beaker again, and repeating the process of S110.
S113, standing the primary samples prepared twice for 24 hours at normal temperature, respectively extracting upper oil samples, mixing, adding 20mL of absolute ethyl alcohol, shaking up, and heating at 60 ℃ for 18 hours on an electric hot plate to prepare a crude oil sample to be tested.
S120, separating and purifying chromium elements in the crude oil sample:
1) accurately weighing 1g of crude oil sample in a high-pressure closed digestion tank, and adding 2mL of CH2Cl2Fully dissolving the crude oil, and then adding 5mL of concentrated HNO3-H2O2Digesting the reagent at the high temperature of 200 ℃ for 5min, cooling, using high-purity water to fix the volume to 10mL, and placing the fixed-volume sample in a drying cabinet at the temperature of 600 ℃ for 24h to remove organic matters.
2) 2mL of HNO was added3And 4mL of HF, covering a cover, dissolving the sample, and putting the sample into an oven to react for 48 hours at 220 ℃; the steps can be repeated until the sample is completely dissolved, the sample is taken out after cooling, and the sample is dried on a heating plate at 200 ℃ until the sample is in a wet salt state; then 2mL of HNO3Removing excessive HF, repeating for 3 times to remove HF, and adding 5mL of 6mol/L HCl, evaporated to dryness to powder.
3) And (3) putting 7g of lithium tetraborate and 0.02g of lithium bromide into a quartz crucible, pouring the powder into the quartz crucible, uniformly mixing, putting the mixture into a muffle furnace at 1500 ℃, and standing for 15 min.
4) Putting 100mL of 3mol/L nitric acid into a Teflon cup, adding the heated sample, covering a cover, and uniformly stirring for 2 hours to obtain a Cr sample to be subjected to column separation;
5) purifying the Cr sample by using Bio-Rad AG1X8 cationic resin of 200 meshes and 300 meshes, separating chromium element by using 6mol/L HCl as a medium, evaporating the purified chromium solution to dryness, and converting the chromium solution into 2% HNO3Medium to be tested.
S210, preparing source rock sample powder:
1) selecting a rock sample: and (4) observing whether the surface of the rock sample is fresh or not and the weathering degree, and taking a photo to describe the information of the sample and inputting the information into a sample table. Wrapping the sample with clean cloth, covering the top and bottom surfaces of the sample with a wood board, hammering the wood board with a steel hammer to break the sample, selecting about 5g of sample particles with fresh four sides, no quartz vein and no wormhole structure after the sample is broken, clamping the sample with a disposable clamp, putting the sample into a sample bag, and recording and taking the number. 2) Sample crushing: selecting two identical grinding tanks, placing one of the grinding tanks into an agate ball, a) adding quartz sand into the grinding tank with the agate ball to cover the agate ball in half, screwing the two grinding tanks, placing the grinding tanks on a sample crusher, fixing the grinding tanks, rotating at 1300 rpm for 3 minutes, taking down the quartz powder after the rotation is finished, observing whether the inner surfaces of the grinding tanks are clean, and continuing the step if the inner surfaces of the grinding tanks are not clean. b) Clamping a sample in a sample bag by using a disposable pliers, putting the sample into a grinding tank, screwing the sample on a sample crusher, fixing the sample at a speed of 1300r/min, rotating the sample for 3 minutes, taking down the sample powder after the rotation is finished, pouring the sample powder onto disposable paper, wiping the inner surface of the grinding tank and an agate ball by using a disposable paper towel to pour the sample powder out as much as possible, and pouring the sample powder into the sample bag to record a serial number. c) Washing the grinding tank, and repeating the step a) for 2-3 times (for sure to ensure that the inner surface of the grinding tank is clean). Then the next sample crushing work is carried out in sequence.
S220, separating and purifying chromium in sample powder:
1) crushing the rock by using a sample crusher, weighing about 10g of sample in a 20mL high-pressure digestion tank, adding 20mL of 3mol/L HCl by using a liquid transfer gun, covering a cover, fully reacting, standing for 24h, then washing by using deionized water, centrifuging for ten minutes by using a 3200r/min centrifugal machine after washing for one time, and washing for at least 3 times.
2) Putting into a 75 ℃ oven for reaction for 12-20h, drying, grinding into powder by a weighing spoon, and weighing 6 g.
3) 5g of lithium tetraborate and 0.01g of lithium bromide are taken and put into a quartz crucible, and then the powder is poured into the quartz crucible, evenly mixed and put into a muffle furnace at 1500 ℃ for 15 min.
4) Putting 50mL of 3mol/L nitric acid into a Teflon cup, adding the heated sample, covering a cover, and uniformly stirring for 2 hours to obtain a Cr sample to be subjected to column separation;
5) separating and purifying the Cr sample by using Bio-Rad AG1X8 cation resin of 200 meshes and 300 meshes to separate out chromium, and firstly preparing 2mol/L HNO3The sample is completely dissolved by the solution, and 6mol/L HNO is used3The resin is washed by the solution and deionized water, then the same amount of the isoteogen is washed by the mixed solution of 0.02mol/L HCl and 0.2mol/L HF, and then 8mol/L NH is added3Collecting chromium element in ion exchange resin, evaporating to dryness in oven at 150 deg.C, dissolving with concentrated nitric acid and concentrated hydrochloric acid for three times, and dissolving in 0.3mol/L HNO3Solution, to be tested.
S300, testing and analyzing the content of chromium element:
firstly, crucible cleaning is carried out to prepare for sample digestion:
(1) the interior of the crucible is wiped by alcohol to remove residual organic matter.
(2) The crucible was soaked with detergent for a period of time, the detergent was rinsed clean, and then rinsed 3 times with deionized water.
(3) Placing the crucible in a beaker, adding high-purity water, placing the crucible on an electric hot plate at 120 ℃, keeping the temperature for 48 hours, and then washing the crucible for 3 times by using secondary water. Drying on an electric heating plate for later use.
(4) And putting the sample into a clean crucible, placing the crucible in a 600 ℃ muffle furnace for 24 hours, taking out the crucible, cooling the crucible to room temperature, transferring the crucible to a microwave digestion tank, and placing the microwave digestion tank on an electric hot plate to heat the sample until the sample is completely evaporated to dryness.
After the digestion of the sample is completed, the sample dissolution is carried out:
(1) accurately weighing 5g of a sample with chromium content, placing the sample in a high-temperature furnace at 800 ℃ for ashing treatment, and adding 5mL of nitric acid into the treated residue. Placing on an electric heating plate, keeping the temperature at 250 ℃, and heating for dissolving. If turbidity occurs, adding proper amount of 1mol/L hydrochloric acid to remove.
(2) Adding 5mL of each of high-purity HCl and high-purity HF, covering and sealing a steel sleeve, and putting the mixture into an oven at 200 ℃ for constant temperature for 48 hours. After cooling, the mixture was evaporated to dryness on a hot plate, and 3mL of high purity HCl was added and evaporated to a wet salt state (to remove residual HF). The total digestion was then carried out in 6mol/L hydrochloric acid and the solution was made acidic.
(3) The dissolved sample was transferred to a beaker and 1.5mL of HCl and 0.5mL of HNO were added3Stewing for 2h, and then opening the cover to drive fluorine.
(4) The sample is completely evaporated to dryness and added50Cr-54The total chromium content was determined by pouring the Cr double diluent into a clean beaker and completely evaporating it to dryness.
S400, detecting and analyzing stable isotope composition of chromium:
(1) the cleaned and cut samples were crushed and burned at 200-300 ℃ for 10 hours in double distilled HCl-HF-HNO3Is digested and then subjected to a second digestion in aqua regia.
(2) The Cr sample was purified with a Bio-Rad AG1X8 cationic resin (200-300 mesh), and the purified sample was measured with a double focusing multi-receiver Plasma mass spectrometer Nu Plasma HR manufactured by Nu Instruments. The DSN-100 type film was used to exsolve into the plasma.
(3) Washing the sample with 0.5mol/L nitric acid for 5 min; then, the standard sample is washed by 0.05mol/L nitric acid for 3 min.
(4) The MC-ICP-MS is used for measuring isotopes with high precision, the allomones of all isotopes possibly causing chromium interference need to be corrected, the chromium is corrected by using thermal ionization, and the measured chromium isotope ratio result is expressed by the thousandth deviation of a sample relative to a standard sample.
S500, establishing value ranges and boundary value parameters of chromium isotope ratios of oil reservoirs with different cause types through analyzing known chromium isotopes in different deposition environments, hydrocarbon source rocks with different maturity degrees and crude oil and natural gas, summarizing the chromium mass fractionation and non-mass fractionation information characteristics of the oil reservoirs with different cause types, and establishing an identification index chart.
Respectively collecting typical Bohai Bay basin samples, and detecting the composition and content of chromium isotopes in hydrocarbon source rock and crude oil; according to the detection result, establishing value ranges and threshold parameters of chromium isotope ratios of different cause types, summarizing iron quality fractionation and non-quality fractionation information characteristics of oil gas of different types, establishing an identification index chart, determining oil gas sources and causes, and guiding exploration and deployment. Wherein delta of chromium isotope in each oil reservoir sample of Bohai Bay basin53The Cr (‰) data results are given in table 1 below:
TABLE 1 Delta of chromium isotopes in oil reservoir samples of Bohai Bay basin53Cr (‰) data
| Serial number | Sample (I) | δ53Cr(‰) |
| 1 | Bohai Bay continental facies hydrocarbon source rock | -0.10 |
| 2 | Bohai Bay continental facies hydrocarbon source rock | -0.18 |
| 3 | Crude oil for victory oil field | -0.06 |
| 4 | Crude oil for victory oil field | -0.12 |
| 5 | Tarim marine phase hydrocarbon source rock | 0.36 |
| 6 | Tarim marine phase hydrocarbon source rock | 0.62 |
| 7 | Tarim marine crude oil | 0.42 |
| 8 | Tarim marine crude oil | 0.39 |
| 9 | Coal-series hydrocarbon source rock for storehouse car | 0.16 |
| 10 | Coal-series hydrocarbon source rock for storehouse car | 0.20 |
| 11 | Coal crude oil for depot vehicle | 0.13 |
| 12 | Coal crude oil for depot vehicle | 0.19 |
Determining value ranges and boundary value parameters of the chromium isotope ratios of the oil reservoirs with different cause types according to the data in the table 1, summarizing the information characteristics of the chromium mass fractionation and the non-mass fractionation of the oil reservoirs with different cause types, and establishing an identification index chart as shown in fig. 1.
At delta53Cr (‰) -oil deposit type identification index plate, delta of coal crude oil53Cr (thousandths) range of 0.12 to 0.21 thousandths, delta of coal-series hydrocarbon source rock53Cr (mill) range is 0.09-0.26 per mill, delta of sea phase crude oil53Cr (‰) range is 0.37-0.47 ‰, and delta of marine hydrocarbon source rock53Cr (thousandths) range is 0.32-0.66 thousandths, delta of continental-phase crude oil53Cr (‰) range is-0.13 ‰ -0.06 ‰, and delta of continental-phase hydrocarbon source rock53The range of Cr (‰) is-0.22 ‰ -0.08 ‰.
S600, judging the index chart according to the established figure 1, determining the source and the cause of the unknown oil source, and guiding exploration deployment.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.
Claims (14)
1. A method for performing oil source contrast using a chromium isotope, the method comprising the steps of:
s100, separating and enriching chromium elements in the crude oil;
s200, separating and enriching chromium elements in the source rock;
s300, testing and analyzing the content of the chromium element;
s400, detecting and analyzing stable isotope composition of chromium;
s500, establishing delta through analysis of chromium isotopes in known different deposition environments, different maturity hydrocarbon source rocks and crude oil and hydrocarbon source rocks with different properties53Cr,% o-reservoir type identification index chart;
s600, determining the source and cause of an unknown oil source according to the established identification index chart;
s300, the content of the chromium element is analyzed by the test, which comprises the following steps:
1) crucible cleaning and sample digestion: putting the sample into a cleaned crucible, placing the crucible in a 600 ℃ muffle furnace for 24 hours, taking out the crucible, cooling the crucible to room temperature, transferring the crucible to a microwave digestion tank, placing the microwave digestion tank on an electric hot plate, and heating the microwave digestion tank until the sample is completely evaporated to dryness to obtain a sample with chromium content;
2) sample dissolving: placing a sample with chromium content in a high-temperature furnace at 800 ℃ for ashing treatment, adding nitric acid into the treated residue, placing the residue on an electric heating plate, keeping the temperature at 250 ℃, and heating for dissolving; if the turbid matter appears, adding a proper amount of 1mol/L hydrochloric acid to remove;
adding high-purity HCl and high-purity HF, covering and sealing a steel sleeve, and putting the steel sleeve into an oven at 200 ℃ for keeping the temperature for 48 hours; cooling, evaporating to dryness on an electric hot plate, adding high-purity HCl, evaporating to form wet salt, and performing total digestion in 6mol/L hydrochloric acid to make the solution acidic;
the dissolved sample was transferred to a beaker and HCl and HNO were added3Stewing for 2h, and then opening a cover to drive fluorine;
the sample is completely evaporated to dryness and added50Cr-54The total chromium content was determined by pouring the Cr double diluent into a clean beaker and completely evaporating it to dryness.
2. The method of claim 1, wherein δ53Delta of crude oil of coal series in Cr,% o-reservoir type identification index chart53Cr content of 0.12-0.21 ‰, and delta of coal-derived hydrocarbon source rock53Cr content in the range of 0.09-0.26 ‰, and delta of sea-phase crude oil53Cr content in the range of 0.37-0.47%, of marine hydrocarbon source rockδ53Cr, 0.32-0.66 per mill range, delta of continental-phase crude oil53Cr, 0.13-0.06 ‰, delta of continental-facies hydrocarbon source rock53Cr, the range of per mill is-0.22 per mill to-0.08 per mill.
3. The method of claim 1, wherein the source rock and crude oil are derived from an oil field cored or marginal outcrop rock sample, respectively, a petroleum sample from a normal production well.
4. The method according to claim 1, wherein S100 specifically comprises:
s110, preparing a crude oil sample;
s120, separating and purifying chromium elements in the crude oil sample.
5. The method of claim 4, wherein the preparing of the S110 crude oil sample comprises:
s111, taking fresh crude oil, sequentially adding petroleum ether and ethanol for mixing and dissolving, and heating to obtain a primary sample;
s112, weighing fresh crude oil again, and repeating the process of S111;
s113, standing the primary samples prepared twice at normal temperature, respectively extracting upper oil samples, mixing, adding absolute ethyl alcohol, shaking up, and heating to prepare a crude oil sample to be tested.
6. The method of claim 5, wherein in S111, the ratio of crude oil, petroleum ether and ethanol is: 6-8 g: 14-16 mL: 14-16 mL.
7. The method according to claim 5, wherein the heating in S111 is performed at a temperature of 75 to 85 ℃ for 11 to 13 hours.
8. The method according to claim 5, wherein the S113 is left standing for 22 to 24 hours and heated at 60 to 70 ℃ for 16 to 18 hours.
9. The method as claimed in claim 4, wherein the separation and purification of the chromium element in the S120 crude oil sample comprises:
1) digesting a crude oil sample;
2) dissolving the digested sample in HNO3And HF, heating for reaction until the sample is completely dissolved; evaporating to dryness to form wet salt after the reaction is finished, and then using HNO3Removing redundant HF, finally adding HCl, and evaporating to dryness to obtain powder;
3) uniformly mixing the powder with lithium tetraborate and lithium bromide, and then putting the mixture into a muffle furnace for ashing;
4) adding HNO3Putting the sample into a Teflon cup, adding the heated sample, covering the Teflon cup with a cover, and uniformly stirring for reaction to obtain a Cr sample to be subjected to column separation;
5) using AG1X8 cation resin with 200 meshes and 300 meshes to separate and purify a Cr sample, using 6mol/L HCl as a medium to separate chromium element, evaporating the purified chromium solution to dryness, and converting the chromium solution into 2 percent HNO3Medium to be tested.
10. The method according to claim 9, wherein the digestion solvent is dichloromethane and the digestion reagent is HNO3-H2O2And (4) digesting the system.
11. The method according to claim 1, wherein S200 specifically comprises:
s210, selecting and crushing a rock sample to obtain sample powder of the hydrocarbon source rock;
s220, separating and purifying chromium element in the sample powder.
12. The method of claim 11, wherein S210 comprises:
s211, selecting a rock sample;
and S212, crushing the sample, and grinding to obtain sample powder.
13. The method of claim 11, wherein the separation and purification of the chromium element in the S220 sample powder comprises:
1) adding HCl into the sample powder in a high-pressure digestion tank to perform digestion reaction; after the reaction is finished, centrifugally cleaning the mixture by using deionized water;
2) drying the centrifugally cleaned sample, and grinding into powder;
3) uniformly mixing the powder in the step 2) with lithium tetraborate and lithium bromide, and then putting the mixture into a muffle furnace for ashing;
4) adding HNO3Putting the sample into a Teflon cup, adding the heated sample, covering the Teflon cup with a cover, and uniformly stirring for reaction to obtain a Cr sample to be subjected to column separation;
5) using AG1X8 cation resin with 200-300 meshes to separate and purify a Cr sample; firstly, 3mol/L HNO is prepared3The Cr sample is completely dissolved by the solution, and 6mol/L HNO is used3The resin is washed by the solution and deionized water, and then the resin is washed by a mixed solution of 0.02mol/L HCl and 0.2mol/L HF to remove the same amount of the isotopologue; then 8mol/L of NH is used3Collecting chromium element in the ion exchange resin by using the solution; evaporating to dryness in a 150 deg.C oven, dissolving with concentrated nitric acid and concentrated hydrochloric acid for several times, and dissolving in 0.3mol/L HNO3In solution, to be tested.
14. The method of claim 1, wherein stable isotope composition of chromium is analyzed in S400 using multi-receiver inductively coupled plasma mass spectrometer MC-ICP-MS detection.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106153871A (en) * | 2015-03-23 | 2016-11-23 | 中国石油化工股份有限公司 | A kind of OIL SOURCE CORRELATION method |
| CN106442698A (en) * | 2016-11-21 | 2017-02-22 | 南京大学 | Re-Os isotope analysis method for oil and gas system organic matter research |
| CN109253994A (en) * | 2018-10-31 | 2019-01-22 | 中国石油天然气股份有限公司 | A kind of oil-gas-source mercury isotope detection method and device |
-
2019
- 2019-07-08 CN CN201910608133.XA patent/CN110412111B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106153871A (en) * | 2015-03-23 | 2016-11-23 | 中国石油化工股份有限公司 | A kind of OIL SOURCE CORRELATION method |
| CN106442698A (en) * | 2016-11-21 | 2017-02-22 | 南京大学 | Re-Os isotope analysis method for oil and gas system organic matter research |
| CN109253994A (en) * | 2018-10-31 | 2019-01-22 | 中国石油天然气股份有限公司 | A kind of oil-gas-source mercury isotope detection method and device |
Non-Patent Citations (3)
| Title |
|---|
| An improved method of Cr purification for high precision measurement of Cr isotopes by double spike MC-ICP-MS;Jian-Ming Zhu等;《J. Anal. At. Spectrom》;20180328;第33卷;第809-821页 * |
| Contributors to chromium isotope variation of meteorites;Liping Qin等;《Geochimica et Cosmochimica Acta》;20091110;第74卷(第3期);第1124页左栏第1段，第1130页右栏最后1段 * |
| 含水原油中金属含量的测定;居美华;《杭州化工》;20040930;第34卷(第3期);第37页左栏第1段、最后1段，右栏第3段 * |
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