Analysis method for determining lateral migration path of oil and gas

Abstract

The invention discloses an analysis method for determining an oil and gas lateral migration path, which comprises the following steps: (1) analyzing a crude oil sample by utilizing GC * GC-TOFMS (Gas Chromatography-Time of Flight Mass Spectrometry) to obtain peak information of adamantane series compounds; (2) analyzing the crude oil sample by utilizing GC * GC-FID, and calculating the peak area in a GC * GC-FID spectrogram to obtain the content of the adamantane series compounds; (3) establishing a relational graph between the adamantane content and the oil reservoir gas-oil ratio; (4) reconstructing the transformation process of the oil reservoir phase state under the action of gas cut according to the content of adamantane series compounds; (5) establishing the relationship between the gas-oil ratio and the oil-gas reservoir phase state; and (6) establishing a discrimination chart, discriminating the gas cut intensity, determining the phase state of the oil and gas reservoir, and judging the migration path. The oil-gas migration path is determined through the deep oil-gas reservoir phase state, a new index is provided for determination of the deep oil-gas migration path, and a new solution thought is provided for oil-gas resource evaluation.

Description

Technical Field

[0001] This invention relates to an analytical method for determining the lateral migration path of oil and gas, belonging to the field of petroleum sample analysis technology. Background Technology

[0002] Predicting hydrocarbon phase distribution based on gas intrusion intensity to determine hydrocarbon migration paths is a primary issue to be addressed in oil and gas field development, providing a basis for resource exploration. Two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) can effectively identify and quantify highly mature trace compounds such as adamantane, and determine the impact of gas intrusion intensity on fluid phases. Furthermore, methods such as pseudo-ternary phase diagram discrimination and hydrocarbon component block diagram discrimination can be used to determine hydrocarbon types. However, these methods generally suffer from high analysis costs and long processing times.

[0003] Two-dimensional gas chromatography (GC×GC) is a novel analytical technique that effectively separates complex mixtures and responds well to low-abundance compounds. The use of two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC) for qualitative and quantitative analysis of compounds in crude oil has been widely adopted. Adamantane, a common compound in crude oil, is extensively used to identify products of cracking in highly mature oils. Summary of the Invention

[0004] The purpose of this invention is to provide an analytical method for determining the lateral migration paths of oil and gas. It is a new method for determining oil and gas migration paths by utilizing the phase state of oil and gas reservoirs, providing new indicators for determining deep oil and gas migration paths, and offering new solutions for oil and gas resource evaluation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An analytical method for determining the lateral migration paths of oil and gas, the method comprising the following steps: (1) The crude oil sample was analyzed by a two-dimensional gas chromatography-time-of-flight mass spectrometer (GC×GC-TOF MS) to obtain the peak information of adamantane series compounds; (2) The crude oil sample was analyzed by full two-dimensional gas chromatography-hydrogen flame ionization detector to obtain the GC×GC-FID spectrum of adamantane. Based on the peak information of adamantane compounds provided in step (1), the peak area in the GC×GC-FID spectrum was calculated and compared with the peak area of ​​D16-adamantane standard sample to obtain the content of adamantane series compounds. (3) Establish a graph showing the relationship between adamantane content and reservoir gas-oil ratio; (4) The process of gas invasion modifying the reservoir phase state is reconstructed by the content of adamantane series compounds; (5) Establish the relationship between the gas-oil ratio and the phase state of the oil and gas reservoir; (6) Establish a discrimination chart, determine the gas invasion intensity by the content of adamantane series compounds in crude oil, determine the phase state of oil and gas reservoirs, and determine the migration path.

[0006] In the analytical method for determining the lateral migration path of oil and gas in this invention, in step (1), crude oil sample is taken into an autosampler, D16-adamantane standard sample is added, mixed evenly, and then dichloromethane is added. The crude oil sample is analyzed using a two-dimensional gas chromatography-time-of-flight mass spectrometer. The peak information of adamantane series compounds is obtained by comparing the mass spectrum acquired by the instrument with the standard mass spectrum.

[0007] In the analytical method for determining the lateral migration path of oil and gas in this invention, the content of adamantane series compounds obtained in step (2) is the total adamantane content and the content of 4-+3-methyldiadamantane, wherein the content of 4-+3-methyldiadamantane has a good correlation with the reservoir gas-oil ratio (GOR).

[0008] In the analytical method for determining the lateral migration pathways of oil and gas in this invention, the one-dimensional column of the two-dimensional gas chromatography-time-of-flight mass spectrometer is an HP-PONA 50m×0.2mm×0.5µm column; the temperature program is as follows: initial temperature 50℃, hold for 1 min, increase to 120℃ at 20℃ / min, increase to 310℃ at 3℃ / min, hold for 25 min; the two-dimensional column is an Rx17HT 1.5m×0.1mm×0.1µm column; the programmed temperature is 10℃ higher than that of the one-dimensional column; the injection port temperature is 300℃, splitless injection is used, the carrier gas is helium, and the flow rate is 1mL / min; the modulation cycle is 6s, including 1.8s of hot blowing time; for mass spectrometry, the transfer line and ion source temperatures are 300℃ and 240℃, respectively, the detector voltage is 1600V, the mass scan range is 40~600amu, the acquisition rate is 100 spectra / s, and the solvent delay time is 0min.

[0009] In the analytical method for determining the lateral migration path of oil and gas in this invention, the two-dimensional gas chromatography-flame ionization detector analysis method adopts the same chromatographic experimental conditions as the two-dimensional gas chromatography-time-of-flight mass spectrometry, with the flow rates of carrier gas, hydrogen, and air being 23 mL / min, 60 mL / min, and 400 mL / min, respectively; the detector temperature being 310 °C; the acquisition frequency being 200 spectra / s; and the solvent delay time being 9 min.

[0010] In the analytical method for determining the lateral migration path of oil and gas in this invention, the two-dimensional gas chromatography-flame ionization detector consists of a gas chromatograph equipped with a flame ionization detector and a dual-nozzle hot and cold modulator; the time-of-flight mass spectrometer workstation uses Chroma TOF software, and the structure of adamantane compounds can be automatically identified by the software and quantitatively analyzed using standard samples to provide accurate quantitative data on the content of adamantane compounds.

[0011] In the analytical method for determining the lateral migration path of oil and gas in this invention, the phase state of oil and gas reservoirs is divided into condensate gas reservoirs, volatile oil reservoirs, and normal oil reservoirs. For Ordovician carbonate oil and gas reservoirs in the Tarim Basin, the gas-oil ratio of normal oil reservoirs is less than 300 m³. 3 / m 3 The gas-oil ratio in volatile oil reservoirs is between 200 and 1500 m³. 3 / m 3 Condensate gas reservoirs with a gas-oil ratio greater than 1000 m 3 / m 3 .

[0012] The beneficial effects of this invention are: According to the method of the present invention, relying solely on crude oil samples, without the need for cumbersome pretreatment processes, qualitative analysis and quantitative calculation of adamantane in crude oil samples are directly performed through full two-dimensional instrument analysis to determine the intensity of gas intrusion and thus the phase state of the oil and gas reservoir, thereby determining the migration path and realizing efficient and rapid exploration and development of oil and gas fields.

[0013] This invention provides a new indicator for determining deep oil and gas migration paths by utilizing the phase state of oil and gas reservoirs, and offers a new solution for oil and gas resource evaluation. Attached Figure Description

[0014] Figure 1 This is a graph showing the fitted relationship between the gas-oil ratio and the adamantane content.

[0015] Figure 2 This is a graph showing the relationship between the logarithm of the molar concentration of n-alkanes and the number of carbon atoms.

[0016] Figure 3 This diagram illustrates the complex fluid formation and alteration process in the Lungudong region. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the accompanying drawings are an integral part of this application and, together with the embodiments of the present invention, serve to illustrate the principles of the invention, but do not imply limitation on the scope of protection of the present invention.

[0018] As a specific embodiment of the analytical method for determining the lateral migration path of oil and gas provided by the present invention, taking the Ordovician carbonate oil and gas reservoirs in the Tarim Basin as an example, the analytical method specifically includes the following steps: Step 1: Take 200 mg of crude oil sample into a 2 mL autosampler vial, add 40 μL of 0.5 μg / μL D16-adamantane standard sample, mix well, and then add dichloromethane to 1.5 mL. Analyze the crude oil sample using a two-dimensional gas chromatography-time-of-flight mass spectrometer (GC×GC-TOF MS) manufactured by Leco Corporation, USA. Compare the mass spectrum acquired by the instrument with the standard mass spectrum to identify and characterize the adamantane series compounds, obtaining peak information for each compound.

[0019] In this step, the one-dimensional column of the two-dimensional gas chromatography-time-of-flight mass spectrometer (GC×GC-TOF MS) was an HP-PONA (50m×0.2mm×0.5µm); the temperature program was as follows: initial temperature 50℃, hold for 1 min, increase to 120℃ at 20℃ / min, increase to 310℃ at 3℃ / min, hold for 25 min. The two-dimensional column was an Rx17HT (1.5m×0.1mm×0.1µm); the programmed temperature was 10℃ higher than that of the one-dimensional column. The injection port temperature was 300℃, splitless injection was used, helium was used as the carrier gas, and the flow rate was 1 mL / min. The modulation cycle was 6 s, including a 1.8 s hot-blowing time. For mass spectrometry, the transfer line and ion source temperatures were 300℃ and 240℃, respectively, the detector voltage was 1600V, the mass scan range was 40~600 amu, the acquisition rate was 100 spectra / s, and the solvent delay time was 0 min.

[0020] Step 2: Analyze the adamantane using a two-dimensional gas chromatography-flame ionization detector (GC×GC-FID) to obtain the GC×GC-FID spectrum. Based on the peak information of adamantane compounds provided by GC×GC-TOF MS, calculate the peak area of ​​the GC×GC-FID spectrum and compare it with the peak area of ​​the D16-adamantane standard sample to obtain the content of adamantane series compounds.

[0021] In this step, the GC×GC system consists of an Agilent 7890A gas chromatograph equipped with a flame ionization detector (FID) and a dual-nozzle hot and cold modulator. The time-of-flight mass spectrometer workstation uses Chroma TOF software. The structure of adamantane compounds can be automatically identified by the software and quantitatively analyzed using standard samples, providing accurate quantitative data on the content of adamantane compounds.

[0022] In this step, the same chromatographic conditions as GC×GC-TOF MS were used, with flow rates of carrier gas, hydrogen, and air of 23 mL / min, 60 mL / min, and 400 mL / min, respectively. The detector temperature was 310 °C, the acquisition frequency was 200 spectra / s, and the solvent delay time was 9 min.

[0023] Table 1 shows the gas-oil ratio and 4-+3-methyldiadamantane content data for the Tarim Basin.

[0024] Table 1. Gas-oil ratio and 4-+3-methyldiadamantane content data in the Tarim Basin Step 3: Using the adamantane content calculated in Step 2, establish a graph showing the relationship between adamantane content and the reservoir gas-oil ratio. For example... Figure 1 The figure shown is a graph depicting the fitting relationship between the gas-oil ratio and the adamantane content. Figure 1 (a) is a graph showing the fitted relationship between the gas-oil ratio and the content of 4-+3-methyldiadamantane. The fitted formula is: y=4172.1ln(x)-10681, R 2 =0.9362; Figure 1 (b) is a graph showing the fitted relationship between the gas-oil ratio and the total adamantane content. The fitted formula is: y = 3779.31n(x) - 23364, R 2 =0.9228.

[0025] The content of adamantane series compounds was quantitatively calculated by integrating the peak area of ​​the standard sample peak and the peak area of ​​each compound using the internal standard method. The total adamantane content and the 4-+3-methyldiadamantane content were obtained. A graph showing the relationship between the 4-+3-methyldiadamantane content, the total adamantane content and the reservoir gas-oil ratio was fitted. The gas-oil ratio was obtained from the actual production data of the reservoir and represents the ratio of the total natural gas production to the total crude oil production obtained in the early stage of oil and gas production and after stabilization.

[0026] Step 4: Using the adamantane content obtained in Step 2, reconstruct the process by which gas invasion alters the reservoir phase.

[0027] The phase state of oil and gas is determined by the adamantane content, the intensity of gas invasion is determined by the relationship between the adamantane content and the gas-oil ratio, and the direction of gas invasion modification is determined by the fault development. The more severe the gas invasion, the higher the adamantane content, the lack of biomarkers, and the greater the loss of n-alkanes. The weaker the gas invasion intensity, the richer the content of biomarkers, and the very low content of adamantane series compounds.

[0028] Lateral gas intrusion mainly occurs on the slope of hydrocarbon-generating depressions, moving from low to high. The reservoir is most affected at lower elevations, with significant changes in fluid properties and phases. In contrast, gas intrusion has a relatively weaker impact at higher elevations, with little or no change in fluid properties and phases.

[0029] Step 5: Establish the relationship between the gas-oil ratio and the phase state of the oil and gas reservoir. For the Ordovician carbonate oil and gas reservoirs in the Tarim Basin platform area, the oil and gas properties in this region are complex and the phase states are varied. The oil and gas reservoir phase states are divided into condensate gas reservoirs, volatile oil reservoirs, and normal oil reservoirs. Among them, the gas-oil ratio of normal oil reservoirs is generally less than 300 m³ / s. 3 / m 3 Volatile oil reservoirs are generally located at depths of 200–1500 m. 3 / m 3 Condensate gas reservoirs are generally larger than 1000 m 3 / m 3 .

[0030] Step Six: Apply this theory to the Lungu region to verify its effectiveness. For example, this can be verified by analyzing the relationship between the logarithm of the molar concentration of n-alkanes and the number of carbon atoms (…). Figure 2 ), to verify its effectiveness.

[0031] For crude oil that has not undergone secondary alteration due to invasive distillation, the logarithm of the molar concentration of n-alkanes follows a certain linear relationship with the carbon number. In crude oil that has undergone invasive distillation, high-carbon-number n-alkanes are unaffected by the distillation process, while the percentage concentration of low-carbon-number n-alkanes in crude oil that has undergone invasive distillation can be reduced to its pre-invasive percentage concentration based on its high-carbon-number n-alkanes. Generally, the later the carbon number at the breakpoint, the stronger the invasive effect on the crude oil. Figure 2 It is evident that LG38, LG391, and LG32 are areas of strong gas intrusion; LG101, LG11, and LG16-1 are areas of weak gas intrusion; and LG701, LG7, and LG7-2c are not affected by gas intrusion.

[0032] Step 7: Establish a discrimination map for the Lungu region, determine the intensity of gas intrusion by analyzing the content of adamantane series compounds in the crude oil, identify the phase state and structural type of the oil and gas reservoir, and determine the migration path. For example... Figure 3 The diagram shown illustrates the complex fluid formation and alteration process in the Lungudong area. Based on the distribution of oil wells, the gas intrusion effect weakens progressively from east to west.

Claims

1. An analytical method for determining the lateral migration path of oil and gas, characterized in that, The method includes the following steps: (1) The crude oil sample was analyzed by a two-dimensional gas chromatography-time-of-flight mass spectrometer (GC×GC-TOFMS) to obtain the peak information of adamantane series compounds; (2) The crude oil sample was analyzed by full two-dimensional gas chromatography-hydrogen flame ionization detector to obtain the GC×GC-FID spectrum of adamantane. Based on the peak information of adamantane compounds provided in step (1), the peak area in the GC×GC-FID spectrum was calculated and compared with the peak area of ​​D16-adamantane standard sample to obtain the content of adamantane series compounds. (3) Establish a graph showing the relationship between adamantane content and reservoir gas-oil ratio; (4) The process of gas invasion modifying the reservoir phase state is reconstructed by the content of adamantane series compounds; (5) Establish the relationship between the gas-oil ratio and the phase state of the oil and gas reservoir; (6) Establish a discrimination chart, determine the gas invasion intensity by the content of adamantane series compounds in crude oil, determine the phase state of oil and gas reservoirs, and determine the migration path.

2. The analytical method for determining the lateral migration path of oil and gas according to claim 1, characterized in that, In step (1), crude oil sample is placed in an autosampler vial, D16-adamantane standard sample is added, and after mixing evenly, dichloromethane is added. The crude oil sample is analyzed using a two-dimensional gas chromatography-time-of-flight mass spectrometer. The peak information of adamantane series compounds is obtained by comparing the mass spectrum acquired by the instrument with the standard mass spectrum.

3. The analytical method for determining the lateral migration path of oil and gas according to claim 1 or 2, characterized in that, In step (2), the content of the adamantane series compounds is the total adamantane content and the 4-+3-methyldiadamantane content.

4. The analytical method for determining the lateral migration path of oil and gas according to claim 1, characterized in that, The one-dimensional column of the all-two-dimensional gas chromatography-time-of-flight mass spectrometer was an HP-PONA 50m×0.2mm×0.5µm column; the temperature program was as follows: initial temperature 50℃, hold for 1 min, increase to 120℃ at 20℃ / min, increase to 310℃ at 3℃ / min, hold for 25 min; the two-dimensional column was an Rx17HT 1.5m×0.1mm×0.1µm column; the programmed temperature was 10℃ higher than that of the one-dimensional column; the injection port temperature was 300℃, splitless injection, helium as the carrier gas, and the flow rate was 1mL / min; the modulation cycle was 6s, including a 1.8s hot-blowing time; for mass spectrometry, the transfer line and ion source temperatures were 300℃ and 240℃, respectively, the detector voltage was 1600V, the mass scan range was 40~600 amu, the acquisition rate was 100 spectra / s, and the solvent delay time was 0 min.

5. The analytical method for determining the lateral migration path of oil and gas according to claim 1, characterized in that, In step (2), the two-dimensional gas chromatography-flame ionization detector analysis method adopts the same chromatographic experimental conditions as the two-dimensional gas chromatography-time-of-flight mass spectrometer, with the flow rates of carrier gas, hydrogen, and air being 23 mL / min, 60 mL / min, and 400 mL / min, respectively; the detector temperature is 310℃, the acquisition frequency is 200 spectra / s, and the solvent delay time is 9 min.

6. The analytical method for determining the lateral migration path of oil and gas according to claim 1, characterized in that, The two-dimensional gas chromatography-flame ionization detector consists of a gas chromatograph equipped with a flame ionization detector and a dual-nozzle hot and cold modulator; the time-of-flight mass spectrometer workstation uses Chroma TOF software, which can automatically identify the structure of adamantane compounds and perform quantitative analysis using standard samples, providing accurate quantitative data on the content of adamantane compounds.

7. The analytical method for determining the lateral migration path of oil and gas according to claim 1, characterized in that, In step (5), the phases of the oil and gas reservoir are divided into condensate gas reservoirs, volatile oil reservoirs, and normal oil reservoirs. Among them, the gas-oil ratio of the normal oil reservoir is less than 300 m³. 3 / m 3 The gas-oil ratio in volatile oil reservoirs is between 200 and 1500 m³. 3 / m 3 Condensate gas reservoirs with a gas-oil ratio greater than 1000 m 3 / m 3 .

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