An oil and gas development method, device and system based on downhole electric heating

Abstract

This specification provides an embodiment of a method, apparatus, and system for oil and gas development based on downhole electric heating. The method includes: calculating the oil-to-energy ratio based on the oil and gas production volume and the total power of the electric heating tool string during the electric heating extraction process; setting different electric heating tools at different locations in the heated well; adjusting the total power of the electric heating tool string based on the change in the oil-to-energy ratio over time to stabilize the oil-to-energy ratio; when increasing or decreasing the total power results in a decrease in the oil-to-energy ratio, performing differentiated power adjustments for each electric heating tool to determine the target power for each tool; using the sum of the target powers of all electric heating tools to control the oil-to-energy ratio to its maximum; and controlling the output power of the electric heating tool string based on the combined target power. This method minimizes energy consumption while ensuring production volume, thus guaranteeing the practical application value of electric heating development.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of geological exploration and development technology, and in particular to an oil and gas development method, apparatus and system based on downhole electric heating. Background Technology

[0002] Thermal recovery technology is an effective means of improving the efficiency of oil and gas extraction, especially for unconventional oil and gas extraction such as heavy oil, oil sands, and oil shale. Traditional thermal recovery technology mainly uses steam extraction. However, the process of generating steam for thermal recovery not only consumes large amounts of fuel and emits significant amounts of carbon dioxide, but also requires high investment and large land area for steam generation facilities, making it difficult to meet the needs of green and low-carbon oil and gas development and lacking practical application value. In recent years, electric heating for oil and gas extraction has shown a trend of gradually replacing steam extraction due to its advantages such as low carbon emissions, cleanliness, and high efficiency.

[0003] Despite the numerous advantages of electrothermal extraction, the process consumes a significant amount of electricity, which, under current conditions, not only wastes substantial power resources but also offers limited economic benefits, thus restricting the effective application of this technology. Therefore, effectively planning the electrothermal extraction process to minimize electricity consumption while ensuring sufficient oil and gas production is a pressing technical challenge. Summary of the Invention

[0004] The purpose of the embodiments in this specification is to provide an oil and gas development method, apparatus and system based on downhole electric heating, so as to solve the problem of how to ensure the oil and gas development effect and reduce the power consumption during the electric heating extraction process.

[0005] To address the aforementioned technical problems, this specification proposes an oil and gas development method based on downhole electric heating, comprising: calculating the oil-to-energy ratio based on the oil and gas production volume and the total power of the electric heating tool string during the electric heating extraction process; the electric heating tool string includes multiple electric heating tools; different electric heating tools are installed at different locations in the heated well; adjusting the total power of the electric heating tool string based on the change of the oil-to-energy ratio over time to stabilize the value of the oil-to-energy ratio; when the oil-to-energy ratio decreases both when increasing and decreasing the total power, performing differentiated power adjustments for each electric heating tool to determine the target power of each electric heating tool; the sum of the target power of each electric heating tool is used to control the oil-to-energy ratio to be maximized; and controlling the output power of the electric heating tool string based on the combined target power.

[0006] In some embodiments, before calculating the oil-energy ratio based on the oil and gas production and the total power of the electric heating tool string, the method further includes: calculating the total power of the electric heating tool string; the total power is calculated by: determining the heating temperature at which oil and gas resources in the core sample are maximized based on core experiments; calculating the heat energy absorbed by the core sample based on the heating temperature; and calculating the total power based on the absorbed heat energy and the electric heating time.

[0007] Based on the above implementation method, the calculation of the absorbed heat energy of the core sample based on the heating temperature includes: using the formula J1=(T m The absorbed heat energy is calculated as J1 × V × ρ × c, where J1 is the absorbed heat energy, and T is the absorbing heat energy. m T0 is the heating temperature, V is the volume of the core sample, ρ is the density of the core sample, and c is the specific heat capacity of the core sample. The calculation of total power based on absorbed heat energy and electric heating time includes: calculating total power using the formula P = J1 / (η×t2), where P is the total power, η is the conversion power of heat energy to electrical energy, and t2 is the heating time.

[0008] In some embodiments, the calculation of the oil-energy ratio based on the oil and gas extraction volume and the total power of the electric heating tool string during the electric heating extraction process includes: obtaining the oil and gas extraction volume and the total power of the electric heating tool string within a preset time step to calculate the average oil-energy ratio; the total power remains unchanged within the preset time step.

[0009] In some embodiments, adjusting the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio includes: gradually increasing the total power of the electric heating tool string, and continuing to increase the total power until the oil-energy ratio reaches its maximum value as the oil-energy ratio increases; or gradually decreasing the total power of the electric heating tool string, and continuing to decrease the total power until the oil-energy ratio reaches its maximum value as the oil-energy ratio increases.

[0010] Based on the above embodiments, adjusting the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio includes: determining a first maximum oil-energy ratio obtained by increasing the total power and a second maximum oil-energy ratio obtained by decreasing the total power when both increasing and decreasing the total power of the electric heating tool string increase the oil-energy ratio; and adjusting the total power of the electric heating tool string based on the relationship between the first maximum oil-energy ratio and the second maximum oil-energy ratio.

[0011] In some embodiments, the differentiated power adjustment for each electric heating tool includes: adjusting the output power for a single electric heating tool and determining the change in oil-energy ratio during the adjustment process; based on the change in oil-energy ratio, determining the output power corresponding to the maximum oil-energy ratio as the target power of the electric heating tool; and repeating the above adjustment process for all electric heating tools until the target power of each electric heating tool is determined.

[0012] In some implementations, the differentiated power adjustment for each electric heating tool to determine the target power of each electric heating tool includes: determining the target power of each electric heating tool based on an objective function that solves for the minimum value of a nonlinear multivariate function.

[0013] This specification also proposes an oil and gas development device based on downhole electric heating, comprising: an oil-energy ratio calculation module, used to calculate the oil-energy ratio based on the oil and gas production volume and the total power of the electric heating tool string during the electric heating extraction process; the electric heating tool string includes multiple electric heating tools; different electric heating tools are set at different locations in the heated well; a total power adjustment module, used to adjust the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio; a differentiated power adjustment module, used to perform differentiated power adjustment for each electric heating tool when the oil-energy ratio decreases due to the adjustment of the total power, to determine the target power of each electric heating tool respectively; the sum of the target power of each electric heating tool is used to control the oil-energy ratio to be maximized; and an output power control module, used to control the output power of the electric heating tool string in combination with the target power.

[0014] This specification also proposes an oil and gas development system based on downhole electric heating, the system comprising a production module, a heating module, and a central control device; the production module is used to extract oil from the target reservoir and determine the oil and gas production volume; the heating module includes an electric heating tool string; the heating module is used to heat the target reservoir using the electric heating tool string and determine the total power of the electric heating tool string; the central control device includes a memory and a processor; the memory is used to store computer programs / instructions; the processor is used to execute the computer programs / instructions to implement the steps of the above-described oil and gas development method based on downhole electric heating.

[0015] As can be seen from the technical solutions provided in the embodiments of this specification above, in the process of electric heating extraction, the oil-energy ratio is first calculated based on the oil and gas extraction volume and the total power of the electric heating tool string. Then, the total power of the electric heating tool string is adjusted according to the oil-energy ratio to maintain a stable and high oil-energy ratio for oil and gas resource extraction. When increasing or decreasing the total power results in a decrease in the oil-energy ratio, differentiated power adjustments are made for each electric heating tool to determine the target power of each tool, thereby ensuring the maximum oil-energy ratio. Through this method, the power consumption of the electric heating tool string in the electric heating extraction process is effectively controlled, minimizing energy consumption while ensuring the extraction volume, improving the economic performance of electric heating oil and gas development technology, and ensuring the practical application value of electric heating development. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an oil and gas development system based on downhole electric heating, as described in this specification.

[0018] Figure 2 This is a schematic diagram of the structure of an electric heating tool string according to an embodiment of this specification;

[0019] Figure 3 This is a flowchart illustrating an oil and gas development method based on downhole electric heating, as described in this specification.

[0020] Figure 4 This is a schematic diagram illustrating the change of oil-energy ratio over time in an embodiment of this specification.

[0021] Figure 5 This is a schematic flowchart illustrating an oil and gas development method based on downhole electric heating, as described in this specification.

[0022] Figure 6 This is a module diagram of an oil and gas development device based on downhole electric heating, as an embodiment of this specification.

[0023] Explanation of reference numerals in the attached drawings: 1. Oil production equipment; 2. Winding drum; 3. Flexible pipe; 4. Power supply cable; 5. Electric heating tool controller; 6. Electrical control cabinet; 7. Power grid; 8. Traction device; 9. Heated well; 10. Electric heating tool string; 11. Production well; 12. Oil production pipe; 13. Underlying strata; 14. Oil and gas reservoir; 15. Overlying strata; 16. Surface strata; 10-1. Electric heating tool numbered E1; 10-2. Electric heating tool numbered E2; 10-3. Electric heating tool numbered E3; 10-4. Electric heating tool numbered E... n-1 Electric heating tools; 10-5, numbered E n Electric heating tools. Detailed Implementation

[0024] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0025] To better understand the technical solution of this application, an oil and gas development system based on downhole electric heating, as described in this specification, is first introduced. The system includes a production module, a heating module, and central control equipment. For example... Figure 1 The diagram shown is a structural schematic of the oil and gas development system based on downhole electric heating.

[0026] The extraction module is primarily used for extracting oil and gas resources from target reservoirs. For example... Figure 1 The image shows an example of an oil extraction scenario, where the extraction module includes oil extraction equipment 1 and an oil production pipe 12. The oil production pipe 12 is installed in a production well 11, which is excavated into a corresponding rock stratum, for example... Figure 1 The oil is set in the underlying rock layer 13. Oil is extracted from the production well using the oil production equipment 1, and the extracted crude oil is output using the production pipe.

[0027] Correspondingly, the extraction module can also determine the amount of oil and gas extracted. The extracted oil and gas amount is preferably the quantity extracted per unit time, and the time increment can be set according to actual application requirements.

[0028] The heating module primarily heats the oil and gas resources in the reservoir. Heating not only improves the extraction efficiency of oil and gas resources but also effectively enables the extraction of some unconventional oil and gas resources. The heating module is typically installed in the heating well 9, which can be located above the production well 11, for example, within the oil and gas reservoir 14. Above the oil and gas reservoir is the overlying stratum 15, and above the overlying stratum 15 is the surface stratum 16, on which surface facilities are installed.

[0029] The heating module mainly consists of a string of electric heating tools. The string of electric heating tools is composed of multiple electric heating tools connected in series. For example... Figure 2 The diagram shows a schematic of an electric heating tool string, wherein E1, E2, E3, and E are connected in series. n-1 E n Electric heating tools. The specific number of electric heating tools can be determined according to actual application requirements, such as the length of the horizontal section of the horizontal well and the electrical energy required by the reservoir. The spacing between electric heating tools can also be set according to actual application requirements. Generally, the spacing between any two adjacent electric heating tools is set to an equal value.

[0030] The heating module may also include a winding roller 2, a flexible tube 3, a power supply cable 4, an electric heating tool controller 5, an electrical control cabinet 6, a power grid 7, and a traction device 8. The ground power grid 7 transmits electrical energy through the power supply cable 4 to the electrical control cabinet 6, the electric heating tool controller 5, the electric heating tool string 10, and the traction device 8. The function of the electrical control cabinet 6 is to convert the power from the power grid into electrical energy compatible with the electric heating tools, ensuring their normal operation. The electric heating tool controller 5 controls the on / off state and power output of each electric heating tool.

[0031] The flexible tube 3 wound by the ground winding roller 2 is connected to the electric heating tool string 10 inside the heating well. This allows for the smooth insertion of the electric heating tool string 10 and the traction device 8 into the horizontal well, and also enables the pulling of the electric heating tools out of the heating well. The traction device 8 provides pulling force to smoothly guide the electric heating tool string 10 into the designated position within the heating well. Inside the heating well, the traction device 8 is located at the toe end and connected to the electric heating tool string 10 via the flexible tube 3. The traction device 8 moves the electric heating tool string 10 to the corresponding position via a wheel assembly attached to the well wall.

[0032] The central control equipment acquires oil and gas extraction data from the extraction module and power consumption data from the heating module, processes this data to determine the control status of the electric heating tool string under the optimal extraction scheme. Correspondingly, the central control equipment can also control the electric heating tool controller, indirectly controlling the power of the electric heating tools.

[0033] Based on the aforementioned downhole electric heating-based oil and gas development system, this specification proposes an oil and gas development method based on downhole electric heating. The main implementer of the method is the aforementioned central control equipment. For example... Figure 3 As shown, the oil and gas development method based on downhole electric heating includes the following specific implementation steps.

[0034] S310: During the electric heating extraction process, the oil-energy ratio is calculated based on the oil and gas extraction volume and the total power of the electric heating tool string; the electric heating tool string includes multiple electric heating tools; different electric heating tools are set at different locations in the heating well.

[0035] In the process of electrically heated extraction, the oil-to-energy ratio can be calculated based on the oil and gas extraction volume and the total power of the electrically heated tool string. Initially, the power of the electrically heated tool string can be set to a specific value, such as adjusting it to its rated power.

[0036] The oil and gas extraction rate and the total power of the electric heating tool string can be determined by the data transmitted from the extraction module and the heating module. Specifically, the oil and gas extraction rate and the total power of the electric heating tool string can correspond to values ​​over a period of time. Preferably, the total power of the electric heating tool string remains constant during this period to facilitate calculation and adjustment.

[0037] The oil-to-energy ratio is the ratio of oil and gas production to total power output. The higher the oil-to-energy ratio, the less electricity is required to extract the same amount of oil and gas resources.

[0038] In a specific example, the formula for calculating the oil-energy ratio is δ = s / q, where s represents the number of barrels of crude oil produced per day, in bbl / d; q represents the electric heat generated by the electric heating tool string in the heated well per day, in MJ; and the electric heat q and the total power P of the electric heating tool string are also included. t The relationship is: q = 86.4P t Total power P t The unit is kW.

[0039] Since the power of the electric heating tool string cannot be reflected as the power for directly heating the oil and gas reservoir 14 in practical applications, in some embodiments, the total power can be calculated in the following ways: based on the heating temperature at which the oil and gas resources in the core sample are maximized, determined by core experiments; based on the heating temperature, the heat energy absorbed by the core sample is calculated; and based on the absorbed heat energy and the electric heating time, the total power is calculated.

[0040] Specifically, the formula J1 = (T) can be used. m The absorbed heat energy is calculated as J1 × V × ρ × c, where J1 is the absorbed heat energy, and T is the absorbing heat energy. mHere, T0 is the temperature of the core sample before heating, V is the volume of the core sample, ρ is the density of the core sample, and c is the specific heat capacity of the core sample. Correspondingly, the total power can be calculated using the formula P = J1 / (η × t2), where P is the total power, η is the power converted from thermal energy to electrical energy, and t2 is the heating time.

[0041] The calculation process of total power is illustrated using an example: 1. First, the highest temperature T corresponding to the maximum extraction of crude oil from the core is determined based on core experiments. m 2. Calculate the thermal energy required to heat a reservoir volume of V using the formula: J1 = (T m -T0)×V×ρ×c, where T0 is the temperature of the reservoir before it is heated; ρ is the reservoir density, obtained by measuring the core density; and c is the specific heat capacity of the reservoir, obtained by measuring the specific heat capacity of the core. 3. The thermal energy calculated in step 2 is converted from electrical energy. Due to losses, the conversion power is set to η, so the electrical energy is: J2=J1 / η. The preset heating time is t2 days, so the power is: P=J2 / (3600×24×t2).

[0042] In the initial state, the power of each electric heating tool in the electric heating tool string can be controlled to be the same, that is, the output power of each electric heating tool is P / n (n is the number of electric heating tools contained in the electric heating tool string).

[0043] S320: Adjust the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio.

[0044] Based on the calculated oil-energy ratio, its variation over time can be determined. Under constant total power, the oil-energy ratio generally remains constant or gradually decreases. If the oil-energy ratio decreases, it may be because the heating power is too low to achieve optimal oil and gas resource output, or it may be due to excessive electrical energy output while maintaining the current oil and gas resource output. Therefore, based on the variation of the oil-energy ratio over time, the total power can be adjusted to ensure that the oil-energy ratio remains at its maximum.

[0045] In some implementations, the total power of the electric heating tool string can be gradually increased, and the total power can be continued to increase until the oil-energy ratio reaches its maximum value as the oil-energy ratio increases; or, the total power of the electric heating tool string can be gradually decreased, and the total power can be continued to decrease until the oil-energy ratio reaches its maximum value as the oil-energy ratio increases.

[0046] If the oil-energy ratio increases both when the total power of the electric heating tool string is increased and when the total power is decreased, a first maximum oil-energy ratio obtained by increasing the total power and a second maximum oil-energy ratio obtained by decreasing the total power can be determined respectively. The total power of the electric heating tool string can then be adjusted based on the relationship between the first maximum oil-energy ratio and the second maximum oil-energy ratio. Specifically, the adjustment method corresponding to the larger oil-energy ratio can be determined as the actual adjustment method.

[0047] To illustrate with a specific example, power adjustment includes the following two methods: ① Gradually increase the total power of the electric heating tool string in steps of ΔP1. After a period of time, observe the change in the oil-energy ratio. If the oil-energy ratio increases, continue to increase the total power until the oil-energy ratio reaches its maximum value δ. m1 ② Gradually reduce the total power of the electric heating tool string in increments of ΔP2. Observe the change in the oil-energy ratio over a period of time. If the oil-energy ratio increases, continue to reduce the total power until the oil-energy ratio reaches its maximum value δ. m2 Compare δ m1 and δ m2 The magnitude of the values ​​is used to determine the total power value P corresponding to the maximum value of the two values. m This is the corrected total power of electric heating.

[0048] S330: When the total power is increased or decreased and the oil-energy ratio decreases, differentiated power adjustment is performed for each electric heating tool to determine the target power of each electric heating tool; the sum of the target power of each electric heating tool is used to control the oil-energy ratio to be maximized.

[0049] With prolonged heating and crude oil extraction, the crude oil content in the reservoir area around the horizontal section of the heated horizontal well gradually decreases. In addition, since the reservoir is generally heterogeneous and the reservoir thickness varies along the horizontal direction, the maximum oil-energy ratio will generally gradually decrease.

[0050] When the oil-energy ratio decreases, the power of the electric heating tool string can be adjusted to obtain the maximum oil-energy ratio, following the strategy in step S320. However, in some cases, the oil-energy ratio may gradually decrease regardless of the adjustment method used, which may indicate uneven heating.

[0051] Because the electric heating tool strings are distributed over a long distance, while maintaining the same power for each tool, some tools may contribute more to the oil-to-energy ratio, some may overheat, and some may not have reached their optimal power. Therefore, differentiated power adjustments can be made for each electric heating tool.

[0052] Differentiated power adjustment mainly involves adjusting each electric heating tool individually to maximize the overall oil-energy ratio. Specifically, the output power of a single electric heating tool can be adjusted, and the change in oil-energy ratio during the adjustment process can be determined. Based on the change in oil-energy ratio, the output power corresponding to the maximum oil-energy ratio is determined as the target power of that electric heating tool. Finally, the above adjustment process is repeated for all electric heating tools until the target power of each electric heating tool is determined.

[0053] Correspondingly, the target power can be determined by finding the minimum value of a nonlinear multivariate function to determine the target power of each electric heating tool.

[0054] To illustrate this with a concrete example, consider a string of electric heating tools within the horizontal section of a horizontal well. These tools are numbered E1-E1, distributed from the toe to the heel. n Its output power is set sequentially as P1-P n Since the heating power of each electric heating tool in the electric heating tool string is the same during steps 1)-5), then P1 = P2 = ... P n-1 =P n =P i First, adjust the output power of the electric heating tool numbered E1 to P. i +Δp1, with the output power of the other electrically heated tools remaining unchanged, record the increase in oil-energy ratio Δδ1 for duration t at this power. Similarly, record E2, E3, ... E n-1 and E n At power P i +Δp2、P i +Δp3、…P i +Δp n-1 and P i +Δp n The increase in oil-energy ratio Δδ2, Δδ3, ... Δδ for the same duration t n-1 and Δδ n The output power of the electric heating tool is then determined using an optimization function that solves for the minimum value of a nonlinear multivariate function, where ① variables and initial values: x = [x1, x2, ... x n-1 x n ] = [1, 0, ..., 0, 0]; ② Boundary conditions: 0 ≤ x1 ≤ 1; 0 ≤ x2 ≤ 1; ... 0 ≤ x n-1 ≤1; 0≤x n ≤1; Δp1∈R; Δp2∈R…Δp n-1 ∈R; Δp n ∈R; ③ Objective function: f(x)=1 / (x1Δδ1+x2Δδ2+…+x n-1 Δδ n-1 +xn Δδ n The calculation shows that f(x) is the smallest in ③, which is the increase in the energy-to-oil ratio: x1Δδ1 + x2Δδ2 + ... + x n-1 Δδ n-1 +x n Δδ n Therefore, the calculated output power of each electric heating tool in the electric heating tool string is P. i +x1Δp1、P i +x2Δp2、…P i +x n-1 Δp n-1 and P i +x n Δp n .

[0055] S340: Control the output power of the electric heating tool string based on the target power.

[0056] After determining the target power, the output power of the electric heating tool string is controlled based on the target power. Specifically, each electric heating tool can be adjusted according to its target power to achieve final output power control. This adjustment process can be implemented through the electric heating tool control cabinet to obtain the maximum oil-energy ratio.

[0057] The following is in conjunction with the appendix Figure 5 This will be illustrated using a specific scenario example. For example... Figure 5 The execution steps are performed sequentially as follows to ultimately obtain the output power of the electric heating tool.

[0058] 1) Based on the core data obtained in the early stage of drilling, the porosity, viscosity, oil content, water saturation and other parameters of the reservoir rock sample were obtained by experimental testing. The total power P of the electric heating tool string was determined by numerical simulation calculation. Then the output power of each electric heating tool in the electric heating tool string is P / n (n is the number of electric heating tools in the electric heating tool string).

[0059] 2) After heating for a period of time, the oil production system begins to extract crude oil from the production well to the surface, and plots the oil-energy ratio versus time under the condition of total power P, and calculates the average value δ of the oil-energy ratio within the time period Δd. p .like Figure 4 As shown in the figure, the oil-energy ratio changes over time in an example scenario. As can be seen from the example in the figure, the oil-energy ratio shows an overall trend of gradually decreasing and fluctuating.

[0060] 3) To achieve the maximum average oil-energy ratio δ pTo achieve this, the total heating power P is adjusted during the actual electric heating process: ① Gradually increase the total power of the electric heating tool string with a step size of ΔP1. After a period of time, observe the change in the oil-energy ratio. If the oil-energy ratio increases, continue to increase the total power until the oil-energy ratio reaches its maximum value δ. m1 ② Gradually reduce the total power of the electric heating tool string in increments of ΔP2. Observe the change in the oil-energy ratio over a period of time. If the oil-energy ratio increases, continue to reduce the total power until the oil-energy ratio reaches its maximum value δ. m2 Compare δ m1 and δ m2 The magnitude of the values ​​is used to determine the total power value P corresponding to the maximum value of the two values. m This is the corrected total power of electric heating.

[0061] 4) With prolonged heating and crude oil extraction, the crude oil content in the reservoir area surrounding the horizontal section of the heated horizontal well gradually decreases. Furthermore, because reservoirs are generally heterogeneous and their thickness varies along the horizontal direction, the maximum energy-to-oil ratio gradually decreases to δ. m3 .

[0062] 5) Take measures to increase the total power to increase the oil-to-energy ratio in step 4): ① Gradually increase the total power value according to the step size ΔP3 until the rated heating power of the electric heating tool string is reached, and the oil-to-energy ratio begins to rise to the maximum value δ. m4 Continue following step 4); ② Gradually increase the total power value according to step size ΔP4 until the rated heating power of the electric heating tool string is reached. If the oil-energy ratio does not change, it is determined that there may be an overheating problem. The total power is reduced by step size ΔP5. If the daily oil production remains unchanged, the oil-energy ratio increases due to the reduction in power. Continue following step 4); If the daily oil production decreases, the power decreases, and the oil-energy ratio decreases, then step 6 is required.

[0063] 6) To improve the oil-to-energy ratio in step 4), the heating power of each electric heating tool in the electric heating tool string is adjusted differentially. The electric heating tool string within the horizontal section of the horizontal well contains n electric heating tools, and the electric heating tools distributed from the toe to the heel of the horizontal well are numbered E1-E1. n Its output power is set sequentially as P1-P n Since the heating power of each electric heating tool in the electric heating tool string is the same during steps 1)-5), then P1 = P2 = ... P n-1 =P n =P i First, adjust the output power of the electric heating tool numbered E1 to P. i+Δp1, with the output power of the other electrically heated tools remaining unchanged, record the increase in oil-energy ratio Δδ1 for duration t at this power. Similarly, record E2, E3, ... E n-1 and E n At power P i +Δp2、P i +Δp3、…P i +Δp n-1 and P i +Δp n The increase in oil-energy ratio Δδ2, Δδ3, ... Δδ for the same duration t n-1 and Δδ n .

[0064] 7) The output power of the electric heating tool is determined using the MATLAB optimization function fmincon, which solves for the minimum value of a nonlinear multivariate function.

[0065] ① Variables and initial values: x = [x1, x2, ... x n-1 x n ] = [1, 0, ..., 0, 0]

[0066] ② Boundary conditions: 0≤x1≤1; 0≤x2≤1; …0≤x n-1 ≤1; 0≤x n ≤1; Δp1∈R; Δp2∈R…Δp n-1 ∈R; Δp n ∈R.

[0067] ③ Objective function: f(x) = 1 / (x1Δδ1 + x2Δδ2 + ... + x n-1 Δδ n-1 +x n Δδ n )

[0068] The calculation shows that f(x) is the smallest in ③, which is the increase in the energy-to-oil ratio: x1Δδ1 + x2Δδ2 + ... + x n-1 Δδ n-1 +x n Δδ n Therefore, the calculated output power of each electric heating tool in the electric heating tool string is P. i +x1Δp1、P i +x2Δp2、…P i +x n-1 Δp n-1 and P i +x n Δp n .

[0069] Through the above embodiments and scenario examples, it can be seen that the above method, in the process of electrothermal extraction, first calculates the oil-energy ratio based on the oil and gas extraction volume and the total power of the electrothermal tool string. Then, it adjusts the total power of the electrothermal tool string according to the oil-energy ratio to maintain a stable and high oil-energy ratio for oil and gas resource extraction. When increasing or decreasing the total power results in a decrease in the oil-energy ratio, differentiated power adjustments are made for each electrothermal tool to determine the target power of each tool, thereby ensuring the maximum oil-energy ratio. Through this method, the power consumption of the electrothermal tool string in the electrothermal extraction process is effectively controlled, minimizing energy consumption while ensuring the extraction volume, improving the economic performance of electrothermal oil and gas development technology, and ensuring the practical application value of electrothermal development.

[0070] Based on the above-described oil and gas development method based on downhole electric heating, this specification also proposes an oil and gas development device based on downhole electric heating. For example... Figure 6 As shown, the oil and gas development device based on downhole electric heating includes the following modules.

[0071] The oil-energy ratio calculation module 610 is used to calculate the oil-energy ratio based on the oil and gas production volume and the total power of the electric heating tool string during the electric heating extraction process; the electric heating tool string includes multiple electric heating tools; different electric heating tools are set at different positions in the heating well.

[0072] The total power adjustment module 620 is used to adjust the total power of the electric heating tool string based on the change of the oil-energy ratio over time, so as to stabilize the value of the oil-energy ratio.

[0073] The differentiated power adjustment module 630 is used to perform differentiated power adjustment for each electric heating tool when the total power is adjusted and the oil-energy ratio decreases, so as to determine the target power of each electric heating tool respectively; the sum of the target power of each electric heating tool is used to control the oil-energy ratio to be maximized.

[0074] The output power control module 640 is used to control the output power of the electric heating tool string based on the target power.

[0075] based on Figure 1 The corresponding oil and gas development method based on downhole electric heating, as described in this specification, provides a computer-readable storage medium storing computer programs / instructions. The computer-readable storage medium can be read by a processor via the device's internal bus, and the processor can then implement the program instructions in the computer-readable storage medium.

[0076] In this embodiment, the computer-readable storage medium can be implemented in any suitable manner. The computer-readable storage medium includes, but is not limited to, random access memory (RAM), read-only memory (ROM), cache, hard disk drive (HDD), memory card, etc. The computer storage medium stores computer program instructions. When the computer program instructions are executed, this specification is implemented. Figure 1 The program instructions or modules corresponding to the embodiments.

[0077] In this embodiment, the processor can be implemented in any suitable manner. For example, the processor can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. Specifically, the processor can execute [the following] when it is mounted on a suitable device. Figure 1 The method steps in the corresponding embodiments.

[0078] Although the process described above includes multiple operations that occur in a specific order, it should be clearly understood that these processes may include more or fewer operations, which may be executed sequentially or in parallel (e.g., using parallel processors or a multithreaded environment).

[0079] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0080] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0082] Those skilled in the art will understand that the embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, the embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0083] The embodiments described in this specification can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. The embodiments of this specification can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0084] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0085] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for oil and gas development based on downhole electric heating, characterized in that, include: In the process of electric heating extraction, the oil-energy ratio is calculated based on the amount of oil and gas extracted and the total power of the electric heating tool string; The electric heating tool string includes multiple electric heating tools; different electric heating tools are set at different locations in the heating well; the oil-energy ratio is the ratio of oil and gas production to total power. The total power of the electric heating tool string is adjusted based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio; When the oil-energy ratio decreases both when the total power is increased and decreased, differentiated power adjustments are made for each electric heating tool to determine the target power for each electric heating tool; the sum of the target power of each electric heating tool is used to control the oil-energy ratio to be maximized. The output power of the electric heating tool string is controlled based on the target power.

2. The method as described in claim 1, characterized in that, Before calculating the oil-energy ratio based on the oil and gas production and the total power of the electrically heated tool string, the following steps are also included: Calculate the total power of the electric heating tool string; the total power is calculated by: determining the heating temperature at which the oil and gas resources in the core sample are maximized based on the core experiment; calculating the heat energy absorbed by the core sample based on the heating temperature; and calculating the total power based on the absorbed heat energy and the electric heating time.

3. The method as described in claim 2, characterized in that, The calculation of the absorbed thermal energy of the core sample based on the heating temperature includes: Using the formula J1=(T m The absorbed heat energy is calculated as J1 × V × ρ × c, where J1 is the absorbed heat energy, and T is the finite element. m T0 is the heating temperature, V is the volume of the core sample before heating, ρ is the density of the core sample, and c is the specific heat capacity of the core sample. The calculation of total power based on absorbed heat energy and electric heating time includes: The total power is calculated using the formula P=J1 / (η×t2), where P is the total power, η is the conversion power from heat energy to electrical energy, and t2 is the heating time.

4. The method as described in claim 1, characterized in that, In the process of electrically heated extraction, the calculation of the oil-to-energy ratio based on the oil and gas extraction volume and the total power of the electrically heated tool string includes: The average oil-to-energy ratio is calculated by obtaining the oil and gas extraction volume and the total power of the electric heating tool string within a preset time step; the total power remains constant within the preset time step.

5. The method as described in claim 1, characterized in that, The adjustment of the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio includes: Gradually increase the total power of the electric heating tool string. As the oil-energy ratio increases, continue increasing the total power until the oil-energy ratio reaches its maximum value, or... Gradually reduce the total power of the electric heating tool string. As the oil-energy ratio increases, continue to reduce the total power until the oil-energy ratio reaches its maximum value.

6. The method as described in claim 5, characterized in that, The adjustment of the total power of the electric heating tool string based on the change of the oil-energy ratio over time to stabilize the value of the oil-energy ratio includes: When the oil-energy ratio increases both when the total power of the electric heating tool string is increased and when the total power is decreased, a first maximum oil-energy ratio obtained by increasing the total power and a second maximum oil-energy ratio obtained by decreasing the total power are determined respectively. The total power of the electric heating tool string is adjusted based on the relationship between the first maximum oil energy ratio and the second maximum oil energy ratio.

7. The method as described in claim 1, characterized in that, The differentiated power adjustment for each electric heating tool includes: Adjust the output power for a single electric heating tool and determine the change in oil-energy ratio during the adjustment process; Based on the change in oil-energy ratio, the output power corresponding to the maximum oil-energy ratio is determined as the target power of the electric heating tool; Repeat the above adjustment process for all electric heating tools until the target power of each electric heating tool is determined.

8. The method as described in claim 1, characterized in that, The method of differentially adjusting the power for each electric heating tool to determine the target power for each electric heating tool includes: The target power of each electric heating tool is determined based on the objective function of finding the minimum value of a nonlinear multivariate function.

9. An oil and gas development device based on downhole electric heating, characterized in that, include: The oil-energy ratio calculation module is used to calculate the oil-energy ratio based on the oil and gas extraction volume and the total power of the electric heating tool string during the electric heating extraction process. The electric heating tool string includes multiple electric heating tools; different electric heating tools are set at different locations in the heating well; the oil-energy ratio is the ratio of oil and gas production to total power. The total power adjustment module is used to adjust the total power of the electric heating tool string based on the change of the oil-energy ratio over time, so as to stabilize the value of the oil-energy ratio; A differentiated power adjustment module is used to perform differentiated power adjustment for each electric heating tool when the total power is adjusted and the oil-energy ratio decreases, so as to determine the target power of each electric heating tool; the sum of the target power of each electric heating tool is used to control the oil-energy ratio to be maximized; The output power control module is used to control the output power of the electric heating tool string based on the target power.

10. An oil and gas development system based on downhole electric heating, characterized in that, The system includes a mining module, a heating module, and a central control device; The extraction module is used to extract oil and gas resources from the target reservoir and determine the amount of oil and gas extracted. The heating module includes an electric heating tool string; the heating module is used to heat the target reservoir through the electric heating tool string and determine the total power of the electric heating tool string; The central control device includes a memory and a processor; the memory is used to store computer programs / instructions; the processor is used to execute the computer programs / instructions to implement the steps of the method as described in any one of claims 1-8.

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