Simulation device and simulation method for electrical heating in-situ conversion of oil shale
By designing an in-situ conversion simulation device for oil shale electrothermal heating, using sensors to monitor and control the electrothermal process, and optimizing well network matching, the problem of the influence of shale reservoir heterogeneity was solved, and efficient energy transmission and economically feasible energy input were achieved.
Patent Information
- Application Number
- CN202411078982.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies cannot effectively reflect the impact of shale reservoir heterogeneity on in-situ conversion of oil shale, and the high cost of electric heating in-situ conversion technology leads to low energy utilization efficiency, making it difficult to achieve economically feasible energy input.
Design an in-situ conversion simulation device for oil shale electric heating, which includes a simulated oil shale rock mass, a heating well, and a production well. Equipped with temperature and pressure sensors, the device monitors and controls the electric heating throughout the process, and optimizes well network matching and energy transmission strategies.
It improves the energy utilization efficiency of electric heating, scientifically and accurately simulates the mining development process, determines the optimal heating temperature window and well network strategy, achieves efficient energy transmission, and reduces costs.
Smart Images
Figure CN121497301A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of shale oil extraction technology, and relates to a simulation device for in-situ electric heating conversion of oil shale, and more particularly to a simulation device and simulation method for in-situ electric heating conversion of oil shale. Background Technology
[0002] Shale oil refers to the collective term for retained oil and unconverted organic matter in shale. Based on differences in organic matter maturity (vitrinite reflectance Ro), shale oil can be divided into two categories: medium-high maturity shale oil (Ro ≥ 0.95%) and medium-low maturity shale oil (Ro < 0.95%). Medium-high maturity shale oil has become an important area for global oil exploration and development. Exploration and development practice has proven that due to the low organic matter maturity and underdeveloped organic pores in medium-low maturity shale oil, fluid flow is difficult, and existing horizontal well volumetric fracturing technology cannot achieve large-scale development. However, medium-low maturity shale oil can be developed using in-situ conversion technology.
[0003] Preliminary research estimates that the recoverable resources of medium- and low-maturity shale oil using in-situ conversion technology worldwide are approximately 1.4 trillion tons. With the current global crude oil production scale of 7.5 billion tons per year, the development of medium- and low-maturity shale oil resources using in-situ conversion technology could last for about 200 years, indicating a very promising future.
[0004] Currently, there are numerous methods for in-situ pyrolysis of oil shale, each with its own advantages and disadvantages. The key to in-situ pyrolysis of oil shale is the migration of pyrolysis products; the generated shale oil and gas should be transported out of the oil shale layer as much as possible to avoid being trapped underground. Small-well-spacing electric heating technology is currently the most mature in-situ conversion technology for medium- and low-maturity shale oil. By continuously heating the shale oil reservoir with heating cables, the oil and gas trapped in the shale oil and unconverted organic matter can be effectively converted into light oil and natural gas.
[0005] However, experimental physical simulation studies on the in-situ electrothermal conversion of oil shale mainly employ core holders to conduct one-dimensional experiments on shale cores. Such one-dimensional experiments cannot reflect the impact of shale reservoir heterogeneity on the in-situ conversion of shale oil, nor can they reflect the variation patterns of the shale oil reservoir temperature field and its influence on shale oil conversion efficiency. Furthermore, high cost remains the biggest constraint on the technology of electrothermal in-situ conversion of medium- and low-maturity shale oil.
[0006] Therefore, how to provide a simulation device and method for in-situ conversion of oil shale by electric heating, improve the utilization efficiency of electric heating energy, and thus formulate an efficient and economically feasible energy input rate has become an urgent problem to be solved by those skilled in the art. Summary of the Invention
[0007] The purpose of this invention is to provide a simulation device and method for in-situ conversion of oil shale by electric heating. The simulation device improves the utilization efficiency of electric heating energy, thereby enabling the formulation of an efficient and economically feasible energy input rate.
[0008] To achieve this objective, the present invention adopts the following technical solution:
[0009] In a first aspect, the present invention provides a simulation device for in-situ electric heating conversion of oil shale, the simulation device comprising a model container and a simulated oil shale rock mass placed inside the model container, and the gap between the simulated oil shale rock mass and the model container is filled with epoxy resin.
[0010] At least one simulated heating well and at least one simulated production well are drilled longitudinally in the simulated oil shale rock mass, and temperature sensors and pressure sensors are distributed at multiple points around the simulated heating well.
[0011] The simulated production well is connected to a gas-liquid collection device, which quantitatively calculates the composition and quantity of the produced oil and gas.
[0012] This invention simulates the entire process of in-situ electric heating transformation and extraction of oil shale by drilling heating wells and production wells within a simulated oil shale mass. This not only allows for the study of the impact of oil shale heterogeneity on in-situ transformation and the influence of different well patterns on the in-situ transformation of medium- and low-maturity oil shale, thus providing a more scientific and accurate simulation of the actual development and production process in the mining area, but also allows for the selection of different heating well patterns and production well types according to research needs, thereby exploring the optimal matching method between heating well patterns and production well patterns.
[0013] Furthermore, this invention utilizes multi-point distributed temperature sensors to control and monitor the entire heating process of electric heating, proposing methods for temperature-pressure inversion and inter-well temperature difference to explore the heating and heat transfer laws of the heater. Simultaneously, by analyzing factors such as shale oil products and production rates, the optimal heating temperature window of the model and the electrical control strategy for the heater well network are determined, thereby achieving the goal of high-efficiency energy transfer to the shale oil reservoir. This invention also utilizes multi-point distributed pressure sensors to characterize the seepage laws and pressure difference changes during shale oil transfer and production processes, facilitating the exploration of the migration laws and influencing factors of medium- and low-maturity shale oil after its formation.
[0014] Preferably, the simulated heating well and the simulated production well are independently horizontal wells or vertical wells.
[0015] Preferably, an ice bath device is provided between the simulated production well and the gas-liquid collection device.
[0016] Preferably, a resistance heating rod is installed inside the simulated heating well.
[0017] Preferably, the simulated production well is a stainless steel pipe with a filter screen at one end.
[0018] Secondly, the present invention provides a simulation method for in-situ electrothermal conversion of oil shale using the simulation device described in the first aspect, the simulation method comprising the following steps:
[0019] (1) Apply confining pressure to the simulated oil shale rock mass in the simulation device to simulate the original formation pressure;
[0020] (2) The simulated oil shale rock mass in the simulation device is electrically heated;
[0021] (3) The gas-liquid collection device is used to sample the simulation device, and the oil and gas components and output are quantitatively calculated respectively.
[0022] Preferably, nitrogen is used to apply the confining pressure in step (1).
[0023] Preferably, the relative pressure of the confining pressure applied in step (1) is 0-30 MPa, for example, it can be 0 MPa, 2 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa, 12 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa, 22 MPa, 24 MPa, 26 MPa, 28 MPa or 30 MPa, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0024] Preferably, the power of the electric heating in step (2) is ≥100W, for example, it can be 100W, 200W, 30W, 400W, 500W, 600W, 700W, 800W, 900W, 1000W, 1500W or 2000W, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0025] Preferably, the target temperature for electric heating in step (2) is 200-600℃, for example, it can be 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃ or 600℃, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0026] Preferably, the sampling frequency of the sampling operation in step (3) is 1-3 times / day, for example, it can be 1 time / day, 2 times / day or 3 times / day, and the sampling is carried out for a total of 3-30 days, for example, it can be 3 days, 5 days, 10 days, 15 days, 20 days, 25 days or 30 days, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0027] Preferably, the final sampling operation is performed when the relative pressure of the simulated oil shale rock mass drops to 0 MPa.
[0028] Preferably, when the relative pressure of the simulated oil shale rock mass drops to 0 MPa, the porosity and permeability of different parts of the core are measured.
[0029] Preferably, when the relative pressure of the simulated oil shale rock mass drops to 0 MPa, the core is cleaned with solvent and the residual oil in the core is measured.
[0030] As a preferred embodiment of the second aspect of the present invention, the simulation method includes the following steps:
[0031] (1) Nitrogen gas was used to apply confining pressure to the simulated oil shale rock mass in the simulation device, and the relative pressure of the confining pressure was controlled to be 0-30 MPa to simulate the original formation pressure;
[0032] (2) The simulated oil shale rock mass in the simulation device is electrically heated, and the power of the electric heating is controlled to be ≥100W, with a target temperature of 200-600℃;
[0033] (3) A gas-liquid collection device is used to sample the simulation device, and an ice bath device is set between the gas-liquid collection device and the simulation device to convert the gaseous light oil into liquid. The sampling frequency is controlled at 1-3 times / day, and sampling is carried out for a total of 3-30 days. The oil and gas components and output are quantitatively calculated respectively. When the relative pressure of the simulated oil shale rock mass drops to 0MPa, the final sampling operation is carried out, and the porosity and permeability of different parts of the core are measured. Then, the core is cleaned with solvent and the residual oil in the core is measured.
[0034] The numerical range described in this invention includes not only the point values listed above, but also any point values within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values included in the range.
[0035] Compared with the prior art, the present invention has the following beneficial effects:
[0036] (1) This invention simulates the entire process of in-situ electric heating transformation and extraction of oil shale by drilling heating wells and production wells within a simulated oil shale body. This not only allows for the study of the impact of the heterogeneity of oil shale on in-situ transformation and the impact of different well patterns on the in-situ transformation of medium and low maturity oil shale, thus simulating the actual development and production process of the mine more scientifically and accurately, but also allows for the selection of different heating well patterns and production well types according to research needs, thereby exploring the optimal matching method between heating well patterns and production well patterns.
[0037] (2) This invention utilizes multi-point distributed temperature sensors to control and monitor the heating process of electric heating throughout the entire process, and proposes temperature and pressure inversion and well temperature difference methods to explore the heating and heat transfer laws of the heater. At the same time, by analyzing factors such as shale oil products and production rate, the optimal heating temperature window of the model and the power control strategy of the heater well network are determined, thereby achieving the goal of high-efficiency energy transfer to shale oil reservoirs. This invention utilizes multi-point distributed pressure sensors to characterize the seepage law and pressure difference change characteristics during the shale oil transfer and production process, which is convenient for exploring the migration law and influencing factors of medium and low maturity shale oil after its formation. Attached Figure Description
[0038] Figure 1 This is a schematic diagram of the simulation device for in-situ electric heating conversion of oil shale provided in Example 1;
[0039] Figure 2 This is a schematic diagram of the model container and simulated oil shale rock mass provided in Example 1;
[0040] Figure 3 This is a schematic diagram showing the distribution of simulated heating wells and simulated production wells in a simulated oil shale rock mass provided in Example 1;
[0041] Figure 4 This is a schematic diagram of the structure of the simulated oil shale rock mass provided in Example 1.
[0042] The components are as follows: 1-Data processing device; 2-Data receiving device; 3-Simulation unit; 4-Ice bath device; 5-One-way valve; 6-Gas-liquid separator; 7-Oil sample collection device; 8-Back pressure valve; 9-Gas phase component analyzer; 10-Gas collection device; 11-Hydraulic device; 12-Model container; 13-Simulated oil shale rock mass; 14-Epoxy resin; 15-Simulated heating well; 16-Simulated production well; 17-Temperature sensor. Detailed Implementation
[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.
[0044] Example 1
[0045] This embodiment provides a simulation device for the in-situ electric heating conversion of oil shale, such as... Figure 1As shown, the simulation device includes a simulation unit 3, an ice bath device 4, and a gas-liquid separator 6 connected in sequence. The simulation unit 3 is also connected in sequence to a data receiving device 2 and a data processing device 1. The gas phase outlet of the gas-liquid separator 6 is connected to a gas phase component analyzer 9 and a water pressure device 11 via a back pressure valve 8. The liquid phase outlet is equipped with a one-way valve 5, and an oil sample collection device 7 is placed below it. The outlet of the gas phase component analyzer 9 is equipped with a gas collection device 10. The gas phase component analyzer 9 performs quantitative analysis on the produced oil and gas components, separately counts the gas and liquid contents in the oil sample collection device 7 and the gas collection device 10, and quantitatively calculates the output.
[0046] like Figure 2 As shown, the simulation unit 3 has a model container 12 and a simulated oil shale rock mass 13 placed inside the model container 12, and the gap between the simulated oil shale rock mass 13 and the model container 12 is filled with epoxy resin 14. The space formed between the inner wall steel plate of the simulation unit 3 and the model container 12 is covered with an inner cavity cover steel plate and covered with an insulation cover (not shown in the figure).
[0047] like Figure 3 As shown, the simulated oil shale rock mass 13 has one simulated heating well 15 and two simulated production wells 16 drilled longitudinally, and the simulated heating well 15 and the simulated production wells 16 are each independently horizontal wells.
[0048] like Figure 4 As shown, temperature sensors 17 and pressure sensors (not shown in the figure) are distributed at multiple points around the simulated heating well 15. The temperature and pressure data measured by the temperature sensors 17 and pressure sensors are transmitted to the data receiving device 2, and then the relevant data are calculated and analyzed in the data processing device 1.
[0049] In this embodiment, the simulated oil shale rock mass 13 has dimensions of 35cm×30cm×20cm, and the simulated heating well 15 and the simulated production well 16 both have dimensions of 35cm×φ1.0cm. The simulated heating well 15 is equipped with a resistance heating rod, and the simulated production well 16 is a stainless steel pipe with a filter screen at the end.
[0050] Application Example 1
[0051] This application example uses the simulation device provided in Example 1 to simulate the in-situ conversion of oil shale by electric heating. The specific simulation method includes the following steps:
[0052] (1) Nitrogen gas was used to apply confining pressure to the simulated oil shale rock mass 13 in the simulation device, and the relative pressure of the confining pressure was controlled to be 5 MPa to simulate the original formation pressure.
[0053] (2) The simulated oil shale rock mass 13 in the simulation device is electrically heated, and the power of the electric heating is controlled at 2000W. When the rock mass temperature reaches 300℃, the power is gradually reduced so that the rock mass temperature increases slowly.
[0054] (3) When the rock mass temperature reaches 350℃, continue heating for 2 days. Use gas-liquid separator 6 to sample the simulation device and use ice bath device 4 to convert gaseous light oil into liquid. Control the sampling frequency to 1 time / day and sample for a total of 3 days. Quantitatively calculate the oil and gas components and output. When the relative pressure of the simulated oil shale rock mass 13 drops to 0MPa, perform the final sampling operation and measure the porosity and permeability of different parts of the core. Then use solvent to clean the core and measure the residual oil in the core.
[0055] Therefore, this invention, by drilling heating wells and production wells within simulated oil shale bodies, directly simulates the entire process of in-situ electric heating transformation and extraction of oil shale. This not only allows for the study of the impact of oil shale heterogeneity on in-situ transformation and the influence of different well patterns on the in-situ transformation of medium- and low-maturity oil shale, thus simulating the actual development and production process of the mine more scientifically and accurately, but also allows for the selection of different heating well patterns and production well types according to research needs, thereby exploring the optimal matching method between heating well patterns and production well patterns.
[0056] Furthermore, this invention utilizes multi-point distributed temperature sensors to control and monitor the entire heating process of electric heating, proposing methods for temperature-pressure inversion and inter-well temperature difference to explore the heating and heat transfer laws of the heater. Simultaneously, by analyzing factors such as shale oil products and production rates, the optimal heating temperature window of the model and the electrical control strategy for the heater well network are determined, thereby achieving the goal of high-efficiency energy transfer to the shale oil reservoir. This invention also utilizes multi-point distributed pressure sensors to characterize the seepage laws and pressure difference changes during shale oil transfer and production processes, facilitating the exploration of the migration laws and influencing factors of medium- and low-maturity shale oil after its formation.
[0057] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A simulation device for in-situ electric heating conversion of oil shale, characterized in that, The simulation device includes a model container and a simulated oil shale rock mass placed inside the model container, and the gap between the simulated oil shale rock mass and the model container is filled with epoxy resin. The simulated oil shale rock mass is drilled longitudinally with at least one simulated heating well and at least one simulated production well, and temperature sensors and pressure sensors are distributed at multiple points around the simulated heating well. The simulated production well is connected to a gas-liquid collection device, which quantitatively calculates the composition and quantity of the produced oil and gas.
2. The simulation device according to claim 1, characterized in that, The simulated heating well and the simulated production well are each independently a horizontal well or a vertical well; Preferably, an ice bath device is provided between the simulated production well and the gas-liquid collection device.
3. The simulation device according to claim 1 or 2, characterized in that, The simulated heating well is equipped with a resistance heating rod; Preferably, the simulated production well is a stainless steel pipe with a filter screen at one end.
4. A simulation method for in-situ electrothermal conversion of oil shale using the simulation device described in any one of claims 1-3, characterized in that, The simulation method includes the following steps: (1) Apply confining pressure to the simulated oil shale rock mass in the simulation device to simulate the original formation pressure; (2) The simulated oil shale rock mass in the simulation device is electrically heated; (3) The gas-liquid collection device is used to sample the simulation device, and the oil and gas components and output are quantitatively calculated respectively.
5. The simulation method according to claim 4, characterized in that, The confining pressure applied in step (1) is performed using nitrogen gas; Preferably, the relative pressure of the confining pressure applied in step (1) is 0-30 MPa.
6. The simulation method according to claim 4 or 5, characterized in that, The power of the electric heating in step (2) is ≥100W; Preferably, the target temperature for electric heating in step (2) is 200-600℃.
7. The simulation method according to any one of claims 4-6, characterized in that, The sampling frequency of the sampling operation described in step (3) is 1-3 times / day, and the sampling period is 3-30 days. Preferably, the final sampling operation is performed when the relative pressure of the simulated oil shale rock mass drops to 0 MPa.
8. The simulation method according to claim 7, characterized in that, When the relative pressure of the simulated oil shale rock mass drops to 0 MPa, the porosity and permeability of different parts of the core are measured.
9. The simulation method according to claim 8, characterized in that, When the relative pressure of the simulated oil shale rock mass drops to 0 MPa, the core is cleaned with solvent and the residual oil in the core is measured.
10. The simulation method according to any one of claims 4-9, characterized in that, The simulation method includes the following steps: (1) Nitrogen gas was used to apply confining pressure to the simulated oil shale rock mass in the simulation device, and the relative pressure of the confining pressure was controlled to be 0-30 MPa to simulate the original formation pressure; (2) The simulated oil shale rock mass in the simulation device is electrically heated, and the power of the electric heating is controlled to be ≥100W, with a target temperature of 200-600℃; (3) A gas-liquid collection device is used to sample the simulation device, and an ice bath device is set between the gas-liquid collection device and the simulation device to convert the gaseous light oil into liquid. The sampling frequency is controlled at 1-3 times / day, and sampling is carried out for a total of 3-30 days. The oil and gas components and output are quantitatively calculated respectively. When the relative pressure of the simulated oil shale rock mass drops to 0MPa, the final sampling operation is carried out, and the porosity and permeability of different parts of the core are measured. Then, the core is cleaned with solvent and the residual oil in the core is measured.