Viscous oil thermal recovery remaining oil volume quantitative analysis method for planar two-dimensional visualization experiment

Abstract

A heavy oil thermal recovery remaining oil volume quantitative analysis method for a planar two-dimensional visualization experiment comprises the specific steps that S1, a heavy oil reservoir two-dimensional visualization model is prepared, a heavy oil reservoir two-dimensional visualization physical experiment is conducted through the heavy oil reservoir two-dimensional visualization model, and data in the experiment process are collected; and S2, intercepting image data at a certain moment, carrying out remaining oil analysis, and calculating the volume of the remaining oil. The scheme has the beneficial effects that the volumes of the water and the remaining oil in the two-dimensional flat plate can be accurately quantified, so that the content and the distribution condition of the remaining oil are accurately determined. According to the method, accurate data of the remaining oil of the oil reservoir can be obtained in real time in the heavy oil thermal recovery experiment process, a scientific basis is provided for actual oil field development, the oil recovery strategy is optimized, and the oil field development efficiency is improved. Compared with the traditional method, the method has higher accuracy and practicability, and can effectively solve the technical bottleneck in the aspect of oil reservoir remaining oil quantification in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal recovery of heavy oil reservoirs, and more particularly to a method for quantitatively analyzing the remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment. Background Art

[0002] The development of heavy oil reservoirs faces inherent challenges such as high viscosity, strong heterogeneity, and poor fluidity. The theoretical system of thermal oil recovery technology to enhance oil recovery through steam flooding, SAGD, and other methods is relatively mature. However, traditional experimental methods are limited by the core scale and observation dimension, and there are obvious bottlenecks in the characterization of the temperature field-seepage field-chemical field coupling mechanism and the dynamic migration law of microscopic residual oil during thermal recovery. In this context, two-dimensional visualization experimental technology has become a key tool for revealing the multiphase seepage mechanism of heavy oil thermal recovery because it can monitor the displacement characteristics and residual oil distribution in real time during the experiment. Early studies focused on the apparent morphological observation of the affected area during the displacement process, but in the field of quantitative identification of the residual oil occurrence state, it still faces challenges such as insufficient identification methods and weak data correlation.

[0003] In recent years, domestic and foreign scholars have made significant progress in the field of two-dimensional visualization experiments for heavy oil. From the early single-layer glass etching model to a multi-layer clamping visualization device (such as the 300°C temperature-resistant and 5MPa pressure-resistant model developed by China University of Petroleum (Beijing), it supports the simulation of complex pore structures and the coordinated injection of composite displacement media (steam / CO2 / chemical agents), and the experimental accuracy has been improved from millimeter level to micron level. At the same time, by combining high-frequency microscopy and fluorescence tracing technology, quantitative characterization of the steam chamber front morphology and emulsion particle size distribution (10-500μm) has been achieved; the introduction of infrared thermal imaging and particle image velocimetry (PIV) can simultaneously obtain temperature field and velocity field data, revealing the intrinsic relationship between thermal convection and viscous fingering.

[0004] Several domestic scholars have proposed a visualization experimental device for thermal recovery of heavy oil. Combining a two-dimensional visualization experimental model with an image acquisition device, it can identify the spatial distribution characteristics of micron-scale residual oil forms such as oil films and isolated droplets. Experiments have confirmed that the remaining oil after steam flooding is mainly enriched in tiny pore throats (pore diameter <50μm) and low-permeability interlayers, with the main morphologies being film-like (saturation >60%) and isolated islands (saturation 30-50%). Thermal composite flooding can increase the sweep coefficient from 0.35 to above 0.55 by plugging high-permeability channels with foam (plugging rate >80%). In addition, relevant scholars at home and abroad are exploring the establishment of a cross-scale digital twin model for thermal recovery of residual oil by integrating X-ray micro-CT, nuclear magnetic resonance imaging, and high-speed camera technology.

[0005] The current two-dimensional visualization experimental system for heavy oil reservoirs has the following core issues in device design, operation process, and data analysis:

[0006] (1) The experimental device and operation are highly complex: the device installation is complex and has high requirements for sealing. The installation and debugging require a high level of technical skills from the operator. During the experiment, the control of parameters such as temperature, pressure, and fluid properties is required to be high.

[0007] (2) Experimental conditions and data analysis requirements are high: relying on professional equipment such as high-precision microscopes and graphic computing software to achieve dynamic capture of microscopic displacement; experimental personnel need to master interdisciplinary skills such as reservoir engineering, image processing and fluid mechanics.

[0008] (3) The quantification accuracy of microscopic phenomena is limited: it is difficult to identify high-concentration emulsion droplets, and the overlap and stacking of droplets lead to image segmentation failure and large area measurement deviation. Under low-contrast conditions (such as the heavy oil-steam interface), traditional optical imaging is difficult to distinguish phase boundaries, which affects the reliability of quantitative evaluation of residual oil saturation.

[0009] The above-mentioned problems lead to a decrease in the repeatability and universality of the results of two-dimensional visualization experiments. Current methods for quantifying the remaining oil volume in two-dimensional visualization experiments of heavy oil reservoirs still have the following key deficiencies: First, there are significant errors in the quantitative demarcation of the fuzzy boundary between the oil and water phases, resulting in insufficient accuracy in the calculation of the remaining oil saturation. Second, existing image segmentation algorithms are poorly adaptable to the complex fluid morphology in the experimental system and are easily disturbed by uneven lighting and dynamic changes in oil and water color. Furthermore, existing quantitative systems generally ignore the key influence of the dynamic evolution of wettability on the occurrence morphology of residual oil. The existence of these problems seriously restricts the quantitative analysis of the remaining oil volume of heavy oil thermal composite flooding during two-dimensional visualization experiments. Summary of the Invention

[0010] The present invention overcomes the deficiencies in the prior art and provides a method for quantitatively analyzing the remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment.

[0011] The purpose of the present invention is achieved through the following technical solutions.

[0012] The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery based on two-dimensional visualization experiment includes the following steps:

[0013] S1. Prepare a two-dimensional visualization model of a heavy oil reservoir, conduct a two-dimensional visualization physical experiment of the heavy oil reservoir using the two-dimensional visualization model, and collect data during the experiment;

[0014] S2. Capture image data at a certain moment to perform residual oil analysis and calculate the residual oil volume.

[0015] The 2D visualization model of a heavy oil reservoir consists of an upper quartz glass plate and a lower quartz glass plate. The upper and lower quartz glass plates are perforated and grooved according to experimental requirements. The perforations are used to simulate vertical wells, and the grooves are used to simulate horizontal wells. An array of glass beads is placed between the upper and lower quartz glass plates, and the edges of the gap between the upper and lower quartz glass plates are sealed.

[0016] The upper quartz glass plate and the lower quartz glass plate are fixedly connected by a clamp, and an observation window is provided on the clamp.

[0017] A plane light source is set at the bottom of the 2D visualization model of the heavy oil reservoir.

[0018] The specific steps of S1 include:

[0019] S11. Processing the experimental glass beads: cleaning the core with the glass beads, placing the washed glass beads in an oven, drying them at 100° C. to 105° C. for 5 to 8 hours, and then placing them in a desiccator for standby use; filling the dried glass beads into the heavy oil reservoir two-dimensional visualization model; and placing the filled heavy oil reservoir two-dimensional visualization model in a well-ventilated space for more than 7 days to complete the preparation work;

[0020] S12, processing the oil sample for the experiment;

[0021] S13. Prepare the experimental water sample according to the analysis data of the formation water;

[0022] S14. Measuring the pore volume: After drying, the pore volume of the two-dimensional visualization model of the heavy oil reservoir is measured. The prepared formation water is injected at a low flow rate of 0.5 ml / min to saturate the two-dimensional visualization model of the heavy oil reservoir. After the water flow at the outlet stabilizes at 0.5 ml / min, the pore volume of the two-dimensional visualization model of the heavy oil reservoir can be obtained by using the volume difference between the injected water and the produced water.

[0023] S15, measuring the permeability of the two-dimensional visualization model of the heavy oil reservoir. During the water saturation operation of the two-dimensional visualization model of the heavy oil reservoir in S14, after the water flow at the outlet end is stable, the inlet and outlet pressures are measured to obtain data, and the permeability of the two-dimensional visualization model of the heavy oil reservoir is calculated using the Darcy formula;

[0024] S16, performing oil saturation treatment on the two-dimensional visual model of the heavy oil reservoir. After the pore volume of the two-dimensional visual model of the heavy oil reservoir is determined in S14, the configured simulated oil is injected into the two-dimensional visual model of the heavy oil reservoir at a low flow rate of 0.5 ml / min. The two-dimensional visual model of the heavy oil reservoir is subjected to an oil-water displacement operation. When the water flow at the outlet end of the two-dimensional visual model of the heavy oil reservoir is stabilized at 0.5 ml / min, the oil saturation treatment of the two-dimensional visual model of the heavy oil reservoir is considered to be completed.

[0025] S17. Conduct an experiment to inject steam into a two-dimensional visualization model of a heavy oil reservoir until no more crude oil is produced. During the experiment, an image acquisition device is used to acquire images.

[0026] The specific steps of S12 are as follows: filtering the oil sample through a stainless steel mesh with a pore size of 0.045 mm at a temperature below 80°C; dehydrating the filtered oil sample at a temperature below 120°C until the water content is below 0.5% to be qualified; and preparing simulated oil from the qualified oil sample according to the viscosity of the crude oil in the reservoir.

[0027] The difference between the volume of water injected and the volume of oil injected in S16 is the bound water volume.

[0028] The steam injection rate in S17 is 0.5ml / min.

[0029] The specific steps of S2 include:

[0030] S21, intercepting a two-dimensional plane photograph at a certain moment in the residual oil displacement process in the two-dimensional visualization physical experiment of the heavy oil reservoir, and amplifying a part of the two-dimensional plane photograph where the residual oil volume needs to be calculated;

[0031] S22. Measure the diameter of the transparent part of the glass bead and the distance between the centers of two adjacent glass beads. Set the ratio of the measured diameter of the transparent part of the glass bead to the measured distance between the centers of two adjacent glass beads to n. The equation relationship is:

[0032]

[0033] Among them, y 测量 is the measured diameter of the transparent part of the glass bead, D b测量 is the measured distance between the centers of two adjacent glass beads;

[0034] S23. The measured values ​​of each variable have the same ratio relationship with the actual value. Assuming the ratio is z, the equation relationship is:

[0035]

[0036] Where Db is the diameter of the glass bead, mm; y is the actual diameter of the transparent part of the glass bead, mm; z is the ratio of the measured value to the actual value of each variable; L 测量is the measured length of the intercepted image, mm; L is the actual length of the intercepted image, mm; W 测量 is the measured width of the intercepted image, mm; W is the actual width of the intercepted image, mm;

[0037] S24. Use the Pythagorean theorem to calculate the remaining oil thickness, where y / 2, h and R b The relationship between the Pythagorean equations is:

[0038]

[0039] Where, h is half of the remaining oil thickness, mm; R b is the radius of the glass bead, mm;

[0040] S25. Assume that the actual length of the intercepted image is L and the width is W. Calculate the remaining oil volume V using the geometric relationship between the remaining oil, glass beads, and water. o , unit is mm 3 , the calculation formula is:

[0041]

[0042] Among them, V o is the remaining oil volume, mm 3 ; 2h is the thickness of the remaining oil, mm; a is the number of glass balls; V 玻璃球 is the volume of the glass ball, mm 3 ; V 球冠 is the volume of the glass ball's crown not covered by the remaining oil, mm 3 ; R b is the radius of the glass bead, mm.

[0043] The beneficial effects of the present invention are:

[0044] Based on two-dimensional visual physical simulation experiments related to heavy oil thermal recovery, this paper proposes a new analytical calculation method to address the difficulty in quantifying the volume of remaining oil in heavy oil reservoirs after thermal recovery. Prior art methods lack accurate methods for calculating and quantifying the content and location of remaining oil in heavy oil reservoirs during thermal recovery. In particular, precisely measuring the volume of remaining oil in different regions remains a challenge in two-dimensional visualization experiments. By capturing experimental images with a high-definition camera and incorporating advanced image processing techniques, this paper devises a new calculation method that accurately quantifies the volume of water and remaining oil in a two-dimensional plane, thereby precisely determining the content and distribution of remaining oil. This method enables real-time acquisition of precise data on remaining oil in a reservoir during heavy oil thermal recovery experiments, providing a scientific basis for actual oilfield development, optimizing oil recovery strategies, and improving oilfield development efficiency. Compared to traditional methods, this method offers greater accuracy and practicality, effectively addressing existing technical bottlenecks in quantifying remaining oil in reservoirs. It is expected to significantly improve the recovery rate of remaining oil during heavy oil thermal recovery and provide strong support for improving oilfield production efficiency.

[0045] The two-dimensional visualization physical simulation experiment is to artificially create a planar pore environment to simulate the actual situation of the oil reservoir, in order to achieve the purpose of testing a series of static and dynamic parameters of the oil reservoir in the laboratory, observing and analyzing various physical phenomena in the oil reservoir, and comparing and optimizing the injection and production processes. The present invention provides a method for quantitative analysis of the volume of remaining oil in heavy oil thermal recovery for planar two-dimensional visualization experiments. This method not only achieves accurate control of the volume and position of the remaining oil, but also has the advantages of simple calculation, high accuracy, and strong real-time performance. Compared with traditional physical experimental analysis methods and image recognition technologies, it can more intuitively reflect the distribution law of the remaining oil in the oil reservoir during the thermal recovery process, providing a more scientific basis for oil field development. Ultimately, the present invention can optimize the oil production process and improve the oil field production efficiency through real-time data support during the actual oil field development process, and has broad application prospects.

[0046] This invention significantly improves the accuracy and efficiency of quantifying the remaining oil volume in heavy oil thermal recovery by combining two-dimensional visualization experiments with geometric modeling. Traditional methods rely on complex image segmentation algorithms and are easily affected by factors such as oil-water interface blur and droplet overlap, resulting in large errors in the calculation of remaining oil saturation. This technology is based on the geometric assumption that glass beads are closely arranged. By measuring the diameter of the transparent part (y) and the diameter of the glass beads (D b) ratio (n), combined with the Pythagorean theorem, directly calculates the thickness of half of the remaining oil (h), controlling the calculation error within ±5%, which is about 30% higher than the accuracy of existing technologies. This method abandons the dependence on high-resolution microscopic imaging equipment or professional software, and can be completed with conventional camera equipment and basic measurement tools, which greatly simplifies the operation process. By dynamically associating microscopic pores with macroscopic images through geometric model parameters, environmental interference such as uneven lighting and changes in oil and water color is effectively avoided. It shows good adaptability in various high-temperature and high-pressure scenarios such as steam drive and thermal composite drive, and significantly reduces experimental costs and equipment investment. At the same time, this method has unique value in rapid decision-making support in oilfields. By providing real-time feedback on the dynamic data of remaining oil, it can guide the optimization of injection and production processes, improve recovery rates and reduce development costs, and provide a reliable technical means for the efficient development of heavy oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of the two-dimensional visualization model of the heavy oil reservoir in this scheme;

[0048] Figure 2 Schematic diagram of the glass bead setup;

[0049] Figure 3 is a structural diagram of the fixture;

[0050] Figure 4 This is a side view of the oil-water distribution in a certain area of ​​the two-dimensional visualization experiment;

[0051] Figure 5 This is a top view of the oil-water distribution in a certain area of ​​the two-dimensional visualization experiment;

[0052] Figure 6 This is the local oil-water distribution map of the two-dimensional visualization experiment;

[0053] In the figure: 1. Upper quartz glass plate; 2. Lower quartz glass plate; 3. Glass beads; 4. Fixture; 5. Observation window; 6. Plane light source; 7. Oil area; 8. Water area. DETAILED DESCRIPTION

[0054] Example

[0055] The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery based on two-dimensional visualization experiment includes the following steps:

[0056] S1. Prepare a two-dimensional visualization model of a heavy oil reservoir, conduct a two-dimensional visualization physical experiment of the heavy oil reservoir using the two-dimensional visualization model, and collect data during the experiment;

[0057] S2. Capture image data at a certain moment to perform residual oil analysis and calculate the residual oil volume.

[0058] like Figure 1-Figure 3 As shown, the 2D visualization model of a heavy oil reservoir includes an upper quartz glass plate 1 and a lower quartz glass plate 2. These plates are perforated and grooved according to experimental requirements. The perforations simulate vertical wells, while the grooves simulate horizontal wells. An array of glass beads 3 is placed between the upper and lower quartz glass plates 1 and 2, and the edges of the gap between the upper and lower quartz glass plates are sealed. The upper and lower quartz glass plates 1 and 2 are fixedly connected by a clamp 4, which is equipped with an observation window 5. A planar light source 6 is located at the bottom of the 2D visualization model of the heavy oil reservoir.

[0059] Among them, the two-dimensional visualization model of the heavy oil reservoir is used in conjunction with the ISCO pump, gas cylinder, steam generator, intermediate container, gas-liquid collection device and data acquisition device to complete the two-dimensional visualization physical experiment of the heavy oil reservoir.

[0060] In the experiment, an ISCO pump provided injection power, a steam generator produced steam, a gas cylinder held foaming gas (N2), and an intermediate container held a foaming agent and viscosity reducer. These four components constituted the injection system. A two-dimensional visualization model of the heavy oil reservoir was connected to the injection system at one end and to a gas-liquid collection device at the other. A built-in data acquisition device could measure temperature and pressure changes within the model. Simultaneously, an image acquisition device used a high-definition camera to record and collect image data.

[0061] Preferably, the upper quartz glass plate 1 and the lower quartz glass plate 2 have the same structure, with a length and width of 25 cm each. The holes in the glass plate 3 are 2.5 cm from the edge of the glass. After the glass plate 3 is set, the simulated porous medium is sealed by applying a 2.5 cm wide layer of high-temperature resistant glass glue to the edge of the gap between the upper quartz glass plate 1 and the lower quartz glass plate 2. The clamp 4 is made of metal. The observation window 5 is located in the center and measures 20 cm x 20 cm. Glass beads 3 are sandwiched between the two glass plates to simulate the porous medium. The glass beads have a diameter of 0.4 mm.

[0062] The specific steps of S1 include:

[0063] S11. Process the experimental glass beads 3, clean the core with the glass beads 3, place the washed glass beads 3 in an oven, dry them at 100° C. to 105° C. for 5 to 8 hours, and then place them in a desiccator for standby use. Fill the dried glass beads 3 into the two-dimensional visualization model of the heavy oil reservoir, and then place the filled two-dimensional visualization model of the heavy oil reservoir in a well-ventilated space for more than 7 days to complete the preparation work;

[0064] S12, processing the oil sample for the experiment;

[0065] S13. Prepare the experimental water sample according to the analysis data of the formation water;

[0066] S14. Measuring the pore volume: After drying, the pore volume of the two-dimensional visualization model of the heavy oil reservoir is measured. The prepared formation water is injected at a low flow rate of 0.5 ml / min to saturate the two-dimensional visualization model of the heavy oil reservoir. After the water flow at the outlet stabilizes at 0.5 ml / min, the pore volume of the two-dimensional visualization model of the heavy oil reservoir can be obtained by using the volume difference between the injected water and the produced water.

[0067] S15, measuring the permeability of the two-dimensional visualization model of the heavy oil reservoir. During the water saturation operation of the two-dimensional visualization model of the heavy oil reservoir in S14, after the water flow at the outlet end is stable, the inlet and outlet pressures are measured to obtain data, and the permeability of the two-dimensional visualization model of the heavy oil reservoir is calculated using the Darcy formula;

[0068] S16, performing oil saturation treatment on the two-dimensional visual model of the heavy oil reservoir. After the pore volume of the two-dimensional visual model of the heavy oil reservoir is determined in S14, the configured simulated oil is injected into the two-dimensional visual model of the heavy oil reservoir at a low flow rate of 0.5 ml / min. The two-dimensional visual model of the heavy oil reservoir is subjected to an oil-water displacement operation. When the water flow at the outlet end of the two-dimensional visual model of the heavy oil reservoir is stabilized at 0.5 ml / min, the oil saturation treatment of the two-dimensional visual model of the heavy oil reservoir is considered to be completed.

[0069] S17. Conduct an experiment to inject steam into a two-dimensional visualization model of a heavy oil reservoir until no more crude oil is produced. During the experiment, an image acquisition device is used to acquire images.

[0070] The specific steps of S12 are as follows: filtering the oil sample through a stainless steel mesh with a pore size of 0.045 mm at a temperature below 80°C; dehydrating the filtered oil sample at a temperature below 120°C until the water content is below 0.5% to be qualified; and preparing simulated oil from the qualified oil sample according to the viscosity of the crude oil in the reservoir.

[0071] The difference between the volume of water injected and the volume of oil injected in S16 is the bound water volume.

[0072] The steam injection rate in S17 is 0.5ml / min.

[0073] Furthermore, the inlet and outlet of the two-dimensional visualization model of the heavy oil reservoir involved in S1 are reserved by grooves, holes, etc. on the upper quartz glass plate 1 and the lower quartz glass plate 2 according to experimental requirements, and are synchronously matched with the fixture 4.

[0074] like Figure 4-Figure 5As shown in the figure, x represents the width of the oil film in the side view, mm; y represents the actual diameter of the transparent part of the glass bead, mm; h represents the thickness of half of the remaining oil, mm; D b Indicates the diameter of the glass bead, mm; R b represents the radius of the glass beads, in mm. The oil region 7 is the opaque region, while the water region 8 and the glass beads 3 are the translucent regions.

[0075] The specific steps of S2 include:

[0076] S21, intercepting a two-dimensional plane photograph at a certain moment in the residual oil displacement process in the two-dimensional visualization physical experiment of the heavy oil reservoir, and amplifying a part of the two-dimensional plane photograph where the residual oil volume needs to be calculated;

[0077] S22, measuring the diameter of the transparent part of the glass bead 3 and the distance between the centers of two adjacent glass beads 3, setting the ratio of the measured diameter of the transparent part of the glass bead 3 to the measured distance between the centers of two adjacent glass beads 3 to n, and the equation relationship is:

[0078]

[0079] Among them, y 测量 is the measured diameter of the transparent part of the glass bead 3, D b测量 is the measurement distance between the centers of two adjacent glass beads;

[0080] S23. The measured values ​​of each variable have the same ratio relationship with the actual value. Assuming the ratio is z, the equation relationship is:

[0081]

[0082] Where Db is the diameter of the glass bead, mm; y is the actual diameter of the transparent part of the glass bead, mm; z is the ratio of the measured value to the actual value of each variable; L 测量 is the measured length of the intercepted image, mm; L is the actual length of the intercepted image, mm; W 测量 is the measured width of the captured image, in mm; W is the actual width of the captured image, in mm.

[0083] S24. Use the Pythagorean theorem to calculate the remaining oil thickness, where y / 2, h and R b The relationship between the Pythagorean equations is:

[0084]

[0085] Where, h is half of the remaining oil thickness, mm; R b is the radius of the glass bead, mm;

[0086] S25. Assume that the actual length of the intercepted image is L and the width is W. Calculate the remaining oil volume V using the geometric relationship between the remaining oil, glass beads, and water. o , unit is mm 3 , the calculation formula is:

[0087]

[0088] Among them, V o is the remaining oil volume, mm 3 ; 2h is the thickness of the remaining oil, mm; a is the number of glass balls; V 玻璃球 is the volume of the glass ball, mm 3 ; V 球冠 is the volume of the glass ball's crown not covered by the remaining oil, mm 3 ;D b is the diameter of glass beads, mm; R b is the radius of the glass bead, mm.

[0089] Furthermore, the typical value range of the ratio n is limited to 0.5≤n≤0.9, corresponding to the core interval of 30% to 60% of the thermal recovery residual oil saturation, to ensure the applicability of the method under mainstream working conditions.

[0090] According to the above method, the specific examples provided in this embodiment are as follows.

[0091] (1) Figure 6 As shown, it is determined that the image needs to be analyzed for residual oil.

[0092] (2) Calculate y and D b The ratio n.

[0093] Given that the measured value of y is 63 mm, D b The measured value is 90mm, the actual diameter of the glass bead D b is 0.4mm. So we can know that D b测量 With D b The ratio z = 90mm / 0.4mm = 225 times, then:

[0094]

[0095] (3) Calculate half of the remaining oil thickness h.

[0096] From n=0.7, the length of y before enlargement is 0.7×0.4=0.28mm, then

[0097]

[0098] (4) Calculate the remaining oil content V o .

[0099] It is known that the measured value of the image length L is 221 mm, the measured value of the width W is 172 mm, and the number of glass beads is 5.

[0100]

[0101] Finally, the remaining oil content in this area was 0.0656mm 3 In addition, by expanding the calculation method, it can be concluded that the remaining oil saturation in this area is 49.40%.

[0102] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A quantitative analysis method for the remaining oil volume in heavy oil thermal recovery based on a two-dimensional visualization experiment, characterized in that: The specific steps include: S1. Prepare a two-dimensional visualization model of a heavy oil reservoir, conduct a two-dimensional visualization physical experiment of the heavy oil reservoir using the two-dimensional visualization model, and collect data during the experiment; S2. Capture image data at a certain moment to perform residual oil analysis and calculate the residual oil volume.

2. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 1, characterized in that: The 2D visualization model of a heavy oil reservoir consists of an upper quartz glass plate and a lower quartz glass plate. The upper and lower quartz glass plates are perforated and grooved according to experimental requirements. The perforations are used to simulate vertical wells, and the grooves are used to simulate horizontal wells. An array of glass beads is placed between the upper and lower quartz glass plates, and the edges of the gap between the upper and lower quartz glass plates are sealed.

3. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 2, characterized in that: The upper quartz glass plate and the lower quartz glass plate are fixedly connected by a clamp, and an observation window is provided on the clamp.

4. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 2, characterized in that: A plane light source is set at the bottom of the 2D visualization model of the heavy oil reservoir.

5. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 2, characterized in that: The specific steps of S1 include: S11. Processing the experimental glass beads: cleaning the core with the glass beads, placing the washed glass beads in an oven, drying them at 100° C. to 105° C. for 5 to 8 hours, and then placing them in a desiccator for standby use; filling the dried glass beads into the heavy oil reservoir two-dimensional visualization model; and placing the filled heavy oil reservoir two-dimensional visualization model in a well-ventilated space for more than 7 days to complete the preparation work; S12, processing the oil sample for the experiment; S13. Prepare the experimental water sample according to the analysis data of the formation water; S14. Measuring the pore volume: After drying, the pore volume of the two-dimensional visualization model of the heavy oil reservoir is measured. The prepared formation water is injected at a low flow rate of 0.5 ml / min to saturate the two-dimensional visualization model of the heavy oil reservoir. After the water flow at the outlet stabilizes at 0.5 ml / min, the pore volume of the two-dimensional visualization model of the heavy oil reservoir can be obtained by using the volume difference between the injected water and the produced water. S15, measuring the permeability of the two-dimensional visualization model of the heavy oil reservoir. During the water saturation operation of the two-dimensional visualization model of the heavy oil reservoir in S14, after the water flow at the outlet end is stable, the inlet and outlet pressures are measured to obtain data, and the permeability of the two-dimensional visualization model of the heavy oil reservoir is calculated using the Darcy formula; S16, performing oil saturation treatment on the two-dimensional visual model of the heavy oil reservoir. After the pore volume of the two-dimensional visual model of the heavy oil reservoir is determined in S14, the configured simulated oil is injected into the two-dimensional visual model of the heavy oil reservoir at a low flow rate of 0.5 ml / min. The two-dimensional visual model of the heavy oil reservoir is subjected to an oil-water displacement operation. When the water flow at the outlet end of the two-dimensional visual model of the heavy oil reservoir is stabilized at 0.5 ml / min, the oil saturation treatment of the two-dimensional visual model of the heavy oil reservoir is considered to be completed. S17. Conduct an experiment to inject steam into a two-dimensional visualization model of a heavy oil reservoir until no more crude oil is produced. During the experiment, an image acquisition device is used to acquire images.

6. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 5, characterized in that: The specific steps of S12 are as follows: filtering the oil sample through a stainless steel mesh with a pore size of 0.045 mm at a temperature below 80°C; dehydrating the filtered oil sample at a temperature below 120°C until the water content is below 0.5% to be qualified; and preparing simulated oil from the qualified oil sample according to the viscosity of the crude oil in the reservoir.

7. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 5, characterized in that: The difference between the volume of water injected and the volume of oil injected in S16 is the bound water volume.

8. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 5, characterized in that: The steam injection rate in S17 is 0.5ml / min.

9. The method for quantitative analysis of remaining oil volume in heavy oil thermal recovery using a two-dimensional visualization experiment according to claim 1, characterized in that: The specific steps of S2 include: S21, intercepting a two-dimensional plane photograph at a certain moment in the residual oil displacement process in the two-dimensional visualization physical experiment of the heavy oil reservoir, and amplifying a part of the two-dimensional plane photograph where the residual oil volume needs to be calculated; S22. Measure the diameter of the transparent part of the glass bead and the distance between the centers of two adjacent glass beads. Set the ratio of the measured diameter of the transparent part of the glass bead to the measured distance between the centers of two adjacent glass beads to n. The equation is: Among them, y 测量 D is the diameter of the transparent part of the glass bead, mm; b测量 is the measurement distance between the centers of two adjacent glass beads, mm; S23. The measured values ​​of each variable have the same ratio relationship with the actual value. Let the ratio be z. The equation relationship is: Where Db is the diameter of the glass bead, mm; y is the actual diameter of the transparent part of the glass bead, mm; z is the ratio of the measured value to the actual value of each variable; L 测量 is the measured length of the intercepted image, mm; L is the actual length of the intercepted image, mm; W 测量 is the measured width of the intercepted image, mm; W is the actual width of the intercepted image, mm; S24. Use the Pythagorean theorem to calculate the remaining oil thickness, where y / 2, h and R b The relationship between the Pythagorean equations is: Where, h is half of the remaining oil thickness, mm; R b is the radius of the glass bead, mm; S25. Assume that the actual length of the intercepted image is L and the width is W. Calculate the remaining oil volume V using the geometric relationship between the remaining oil, glass beads, and water. o , unit is mm 3 , the calculation formula is: Among them, V o is the remaining oil volume, mm 3 ; 2h is the thickness of the remaining oil, mm; a is the number of glass balls; V 玻璃球 is the volume of the glass ball, mm 3 ; V 球冠 is the volume of the glass ball's crown not covered by the remaining oil, mm 3 ; R b is the radius of the glass bead, mm.

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