Intelligent rock core displacement experimental device

Abstract

The invention provides an intelligent rock core displacement experiment device which comprises a drying box, a rock core geometric parameter measuring device, a constant temperature box, a displacement device and computer equipment, the drying box is started to uniformly dry a rock core, and the computer equipment can obtain measurement parameters related to the rock core; putting the dried rock core into a constant-temperature box, carrying out a displacement experiment under the condition of simulating formation temperature, calculating the recovery ratio by computer equipment, drawing a relation curve between the pressure difference and the flow of fluid passing through the rock core, and further calculating the absolute permeability of the fluid and a possible starting pressure gradient; the relative permeability of the oil phase and the water phase is calculated, and a relative permeability curve is drawn; according to the invention, the problems of separation of displacement experiment from drying and geometric measurement links, indirect calculation by combining data with an empirical formula, large personal error, low efficiency and the like in the rock core displacement experiment are solved; all functional modules of the device are closely connected, the data automatic correlation error is low, and the measurement precision and the automation degree are high.

Description

Technical Field

[0001] The present invention relates to the technical field of core processing, in particular to an intelligent core displacement experimental device. Background Art

[0002] Core experiments are a key step in evaluating reservoir properties and formulating development plans. Traditional core analysis usually requires transferring the cores multiple times between different devices for drying, geometric parameter measurement, and displacement experiments. This is not only cumbersome and time-consuming, with a low degree of automation, but can also easily lead to core structural damage or data distortion due to human intervention. These have become prominent technical difficulties that hinder the efficient development of unconventional oil and gas.

[0003] Core drying is performed in a core dryer. Common core dryers typically place the core on a plate, generate heat through a heating tube, and use an air guide to maintain the dryer temperature at no more than 105°C for approximately eight hours. However, these core dryers cannot precisely control the drying time. If the drying time is insufficient, moisture may remain inside the core. Excessive drying time consumes both energy and time, and may also create safety hazards due to the dryer's prolonged overload.

[0004] In terms of core geometric parameter measurement, the manual measurement mode currently used is a vernier caliper combined with a volume displacement method. This is easily affected by human operating errors, resulting in large measurement errors, and is relatively cumbersome.

[0005] Existing technologies for calculating recovery factors, relative permeability of oil and water phases, and absolute fluid permeability have numerous limitations, severely impacting experimental efficiency and measurement accuracy. First, displacement experiments are separated from drying and geometric measurement, requiring manual data collation and indirect inference based on empirical formulas, resulting in low efficiency. Second, conventional devices operate independently from each other in their functional modules, preventing data from being automatically linked. This results in long experimental cycles and significant error accumulation. This is particularly true in the development of unconventional oil and gas reservoirs, where core heterogeneity is high, making it difficult for traditional methods to meet the demands of high-precision and high-efficiency testing. Summary of the Invention

[0006] The purpose of the present invention is to provide an intelligent core displacement experimental device to solve the technical problems mentioned in the above background technology.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] An intelligent core displacement experimental device includes a drying box, a core geometric parameter measuring device, a constant temperature box, a displacement device and a computer device. A hinged box door is installed on the front side of the drying box. An exhaust channel is provided on the top of the drying box to discharge water vapor generated during the heating and drying process. Two function buttons are also provided on the top of the drying box, corresponding to the core drying and core geometric parameter measurement functions respectively. At the same time, a computer control panel is also provided on the top of the drying box. Drying mechanisms are provided on the four sides of the drying box to evenly dry the core. A core placing table is provided at the bottom of the drying box. A weight sensor is provided on the core placing table to place the core and measure the weight change of the core during the drying process. The core geometric parameter measuring device is provided on the top of the drying box. The numerical measurement device consists of two groups of laser measurement equipment, one group is installed on the left and right sides of the drying box, and the other group is installed on the core placement table; a hinged box door is installed on the front side of the constant temperature box, and a computer control panel is set on the top of the constant temperature box to adjust the temperature of the constant temperature box to maintain it within the formation temperature range; the displacement device consists of a water container, a horizontal flow pump, a six-way valve 1, a six-way valve 2, a pressure gauge 1, a pressure gauge 2, a pressure gauge 3, an intermediate container 1, an intermediate container 2, an intermediate container 3, a flow meter, a core, a core holder, a back pressure valve, an electronic measuring cylinder and a capacitive crude oil water content online measurement device; the volume of the water container needs to be large enough to ensure that the water volume can complete different types of displacement experiments; the inlet end of the horizontal flow pump is connected to the pressure relief valve. The water container is connected through a pipeline to pump water into the bottom of the piston of the intermediate container; the six-way valve 1 is connected to three intermediate containers containing different displacement fluids, and the six-way valve 1 is connected to the pressure gauge 1; the flow meter is connected to the six-way valve 2 through a pipeline to measure the liquid flow at the inlet end of the core holder; the core holder is used to hold the core to be displaced, and the inlet end of the core holder is connected to the six-way valve 2 through a pipeline and then connected to the pressure gauge 2 for real-time measurement of the pressure at the inlet end of the core holder; the back pressure valve is connected to the rear end of the core holder through a pipeline to reduce the pressure at the outlet end of the core holder, and the rear end of the back pressure valve is connected to the pressure gauge 3; the electronic measuring cylinder is connected to the rear end of the pressure gauge 3 through a pipeline to measure the displacement fluid in real time. The height and volume of the body, and the electronic graduated cylinder is also connected to the computer device; the capacitive crude oil water content online measuring device is inserted into the electronic graduated cylinder and the probe is in close contact with the bottom surface of the electronic graduated cylinder, and the capacitive crude oil water content online measuring device is also connected to the computer device; the computer device is connected to the pressure gauge, the electronic graduated cylinder, the drying box control panel, the constant temperature box control panel and the capacitive crude oil water content online measuring device, and is used to obtain the transmitted real-time measurement data and calculate the recovery rate, draw a relationship curve between the pressure difference and flow rate of the fluid passing through the core, and then calculate the absolute permeability of the fluid and the possible starting pressure gradient, and calculate the relative permeability of the oil and water phases and draw the oil-water phase relative permeability curve;

[0009] Furthermore, the drying box door is provided with an observation window for observing the internal state of the drying box during drying; and a groove-shaped handle is also provided for opening and closing the door.

[0010] Furthermore, in order to avoid danger caused by expansion of gas in the drying box due to heating, the exhaust channel is configured as a one-way channel to maintain the air pressure balance inside and outside the drying box.

[0011] Furthermore, the drying mechanism consists of two layers, the lower layer is a bottom plate, on which an air duct is arranged for generating wind to blow heat, and the upper layer is a fixed frame on which a heating tube is arranged for generating heat, and then the heat is evenly blown into the box through the lower air duct.

[0012] Furthermore, the core placing table is composed of an upper core placing table and a lower base, the core placing table is used to place the core, and the base is used to support the upper core placing table; a weight sensor is provided in the base, which can be used to measure the weight change of the core on the upper core placing table; a group of laser measuring equipment is provided on the front and rear sides of the core placing table for measuring the core diameter.

[0013] Furthermore, the core geometric parameter measuring device is composed of two groups of laser measuring equipment, and each group of laser measuring equipment is composed of a laser transmitter and a laser signal receiver, wherein the laser transmitter is used to generate the transmitted laser and the laser signal receiver is used to receive the transmitted laser signal.

[0014] Furthermore, the thermostat is used to simulate the formation temperature; an observation window is provided on the door of the thermostat for observing the internal state of the thermostat during the displacement experiment; and a groove-shaped handle is also provided for opening and closing the door;

[0015] Furthermore, the core holder is placed inside the thermostatic box to ensure that the displacement experiment is carried out at the simulated formation temperature; the inlet end of the core holder is connected to a six-way valve 2 through a pipeline and then connected to a pressure gauge 2 for real-time measurement of the pressure at the inlet end of the core holder and real-time transmission of the data to a computer device; the core to be displaced is placed in the middle of the core holder; the outlet end of the core holder is connected to a back pressure valve through a pipeline to reduce the outlet pressure of the core holder;

[0016] Furthermore, the outlet of the back-pressure valve is connected to a pressure gauge 3 for measuring the pressure at the outlet of the back-pressure valve and transmitting the data to a computer device in real time;

[0017] Furthermore, the electronic graduated cylinder transmits the height and volume of the driven liquid measured in real time to a computer device for calculating the recovery factor;

[0018] Furthermore, the capacitive crude oil water content online measuring device is inserted into an electronic graduated cylinder with the probe in close contact with the bottom surface of the electronic graduated cylinder to measure the water saturation of the liquid displaced from the electronic graduated cylinder. At the same time, the capacitive crude oil water content online measuring device transmits the data to a computer device in real time, which is combined with the data from the electronic graduated cylinder to determine whether the displacement is complete and to calculate the recovery factor.

[0019] Furthermore, the intermediate containers are connected to the inlet end of the thermostat via pipes. The intermediate containers are three parallel liquid containers, each of which is provided with a piston for separating the pumped water from the fluid to be displaced in the intermediate container. The fluids to be displaced are simulated formation water, simulated oil, and simulated ionized water, respectively, for conducting different types of displacement experiments.

[0020] Furthermore, the six-way valve 1 is connected to three intermediate containers containing different displacement fluids. The six-way valve 1 switches different flow paths by rotating the valve core. Flow path 1 simulates the formation water displacement experiment, flow path 2 simulates the oil displacement experiment, and flow path 3 simulates the ionized water displacement experiment.

[0021] Furthermore, the measuring devices in the drying box and the constant temperature box will send the measured data to the computer equipment in real time through the computer control panel for relevant calculations.

[0022] Furthermore, the present invention provides a method for determining whether displacement is complete based on a displacement experiment of the displacement device described above: when displacement is complete, the oil volume in the electronic graduated cylinder remains stable; a computer device receives real-time data transmitted from the electronic graduated cylinder and the capacitive crude oil water content online measurement device, and performs aggregation, calculation, and judgment;

[0023] The calculation formula of the oil-containing volume is:

[0024] Oil content volume = oil content × total liquid volume

[0025] Wherein, the oil content is the oil content in the electronic graduated cylinder, and the calculation formula of the oil content is:

[0026] Oil content = 1-water content

[0027] Wherein, water content is the water content measured in real time by the capacitive crude oil water content online measuring device;

[0028] When the computer device calculates in real time through the above method that the value of the oil volume in the electronic graduated cylinder remains in a stable state, it indicates that the displacement is completed;

[0029] Furthermore, the present invention provides a method for calculating the recovery factor based on the displacement experiment of the above displacement device:

[0030] Step 1: Select a core, place it in a drying oven, and measure the mass m of the core after drying. 干 , radius r, height h;

[0031] Step 2: Rotate the valve core of the six-way valve 1, select the intermediate container 1, and use simulated formation water flooding. The flooding is carried out until the dried core is saturated with simulated formation water. At this time, the water flow rate per unit time into the electronic graduated cylinder remains stable within a certain range. The flow meter transmits the flow rate Q to the computer device in real time through the computer control panel of the thermostat. The computer device calculates the real-time flow rate using the formula:

[0032]

[0033] Where Q is the flow rate measured by the flowmeter; A is the cross-sectional area of the pipe; r is the radius of the pipe; v w is the water flow rate;

[0034] The computer device calculates the porosity of the core using the formula:

[0035]

[0036] Where V 岩 is the core volume; φ is the porosity of the core; V w is the volume of water entering the core, and the formula is:

[0037] V w =v w ×tV 量筒 -V 前管 -V 后管

[0038] Where, v w is the water flow rate; t is the time; V 量筒 is the volume of water in the measuring cylinder; to improve accuracy, the volume of water in the pipes before and after the core holder is also subtracted V 前管 、V 后管 , where relevant pipeline parameters can be input into the computer equipment during installation;

[0039] The computer device calculates the porosity of the core and then calculates the pore volume of the core using the formula:

[0040] V 孔 =V 岩 ×φ

[0041] Where V 孔 is the pore volume of the core; φ is the porosity of the core; V 岩 is the core volume, and the formula is:

[0042] V 岩 =πr2 h

[0043] Where V 岩 is the core volume; r is the core radius; h is the core height;

[0044] Step 3: Rotate the valve core of the six-way valve 1, select the intermediate container 2, and use simulated oil flooding. The displacement is carried out until the computer device calculates that the water volume in the electronic measuring cylinder is maintained at a stable state. The simulated oil flooding experiment is completed, and the computer device obtains the volume of simulated formation water displaced by the oil flooding simulated formation water V 水 ; The computer device calculates the bound water saturation S wi , the formula is:

[0045] S wi =V 孔 -V 水

[0046] Where S wi is the bound water saturation; V 孔 is the pore volume of the core; V 水 is the volume of water displaced by oil after the core is saturated with water;

[0047] Step 4: Rotate the valve core of the six-way valve 1, select the intermediate container 1, and use simulated formation water flooding. At this time, there are both simulated formation water and simulated oil in the core. The flooding is carried out until the computer device calculates that the oil volume in the electronic measuring cylinder remains in a stable state. The simulated formation water flooding experiment is completed, and the computer device obtains the volume V of the simulated oil displaced by the simulated formation water. 油1 The computer device calculates the simulated formation water flooding at the end of the remaining simulated oil volume V in the core or , the formula is:

[0048] V or =V 水1 -V 油1

[0049] Where V 油1 V is the volume of simulated oil displaced from the core saturated with oil and water by flooding with simulated formation water; or V is the volume of simulated oil remaining in the core at the end of simulated formation water displacement; 水1 The volume of simulated formation water displaced by the simulated oil in the core saturated with simulated formation water is given by:

[0050] V 水1 =V 孔 (1-S wi )

[0051] Where V 孔 is the pore volume of the core; Swi is the bound water saturation;

[0052] The computer equipment calculates the residual oil saturation S at the end of the simulated formation water flooding. or , the formula is:

[0053]

[0054] Where V or V is the volume of simulated oil remaining in the core at the end of simulated formation water displacement; 孔 is the pore volume of the core; S or It is the residual oil saturation at the end of simulating formation water displacement.

[0055] The computer device calculates the simulated oil recovery factor η using the formula:

[0056]

[0057] Where S or is the residual oil saturation; S wi is the irreducible water saturation; η is the simulated oil recovery factor;

[0058] Furthermore, the present invention provides a displacement experiment based on the above displacement device, wherein a computer device plots a relationship curve between the pressure difference ΔP between the front and rear ends of the fluid passing through the core and the flow rate Q of the fluid passing through the core, and calculates the absolute permeability k of the fluid and the possible starting pressure gradient;

[0059] Furthermore, the present invention provides a displacement experiment based on the above displacement device, in which a computer device calculates the relative permeability of the oil-water phase using the empirical formula of the oil-water relative permeability and draws the oil-water relative permeability curve. The formula is:

[0060]

[0061] Where S wi is the bound water saturation; S w is the water saturation, and the formula is:

[0062]

[0063] Where V 孔 is the pore volume of the core; V 岩油 is the volume of oil in the core, and the formula is:

[0064] V 岩油 =V 总油 -V 量液 ×(1-W 量 )

[0065] Where V总油 V is the total oil volume in the core before water flooding; 量液 W is the total volume of liquid in the measuring cylinder; 量 The water content in the graduated cylinder is measured by a capacitive crude oil water content online measuring device;

[0066] According to different rock types, select different empirical formulas for oil-water relative permeability in the table:

[0067]

[0068] The present invention has the following advantages: after the rock core is placed on the core placement table of the drying box, the four drying devices distributed in the drying box evenly generate hot air and send it into the drying box body, fully contacting the rock core. At the same time, the weight sensor transmits the rock core weight data to the computer device in real time and displays it on the computer control panel on the top of the drying box. When the rock core weight data tends to be stable, it means that the moisture in the rock core is fully dried. At this time, the computer device controls the drying box to stop working; if the rock core geometric parameters need to be measured, the rock core is placed horizontally, and the two sets of laser measuring devices are started to transmit signals to the computer device. The computer device converts the laser signals emitted and received by the laser measuring devices to obtain the length and diameter of the rock core and displays them on the computer control panel on the top of the drying box. The dried core is placed on the core holder in the constant temperature box, and the horizontal flow pump is turned on. The water in the water container is pumped into the intermediate container through the six-way valve 1 and pushes the piston upward. The displacement hydraulic pressure of the intermediate container is sent to the core holder to complete the core displacement. The displaced liquid flows into the electronic graduated cylinder. The real-time data measured by the electronic graduated cylinder and the capacitive crude oil water content online measurement device are transmitted to the computer equipment for real-time summary and calculation of the recovery factor, the relative permeability of the oil and water phases, and the absolute permeability of the fluid according to the formula. At the same time, the oil and water phase relative permeability curve can also be drawn. Core drying, core geometry parameter measurement, core displacement, recovery factor calculation, oil-water two-phase relative permeability and fluid absolute permeability, and drawing of oil-water two-phase relative permeability curves are all intelligently controlled throughout the process. Compared with traditional core drying, geometry parameter measurement, displacement and recovery factor calculation methods, this system can more fully dry the core and avoid the safety hazards caused by long-term operation of the drying box. It also reduces human error and improves the measurement accuracy of core geometry parameters. At the same time, it also highly automatically completes displacement experiments and calculations of recovery factor, two-phase relative permeability, and fluid absolute permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 Schematic diagram of the overall structure of an embodiment of the present invention.

[0070] Figure 2 Schematic diagram of the external structure of the constant temperature box and the drying box according to an embodiment of the present invention.

[0071] Figure 3This is a schematic structural diagram of a core placement table in a drying box according to an embodiment of the present invention.

[0072] In the figure: thermostat computer control panel-1, exhaust channel-2, drying box computer control panel-3, function button 1 (drying function)-4, function button 2 (core geometry parameter measurement function)-5, thermostat observation window-6, drying box observation window-7, thermostat handle-8, drying box handle-9, thermostat-10, drying box-11, water container-12, horizontal flow pump-13, six-way valve 1-14, pressure gauge 1-15, computer equipment-16, intermediate container 1-17, intermediate Container 2-18, intermediate container 3-19, piston 20, six-way valve 2-21, core holder 22, core 23, back pressure valve 24, pressure gauge 3-25, laser signal transmitter 26, heating tube 27, signal transmission line 28, laser signal receiver 29, air duct 30, base 31, weight sensor 32, core placement table 33, capacitive crude oil water content tester 34, electronic graduated cylinder 35, pressure gauge 2-36, flow meter 37. DETAILED DESCRIPTION

[0073] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0074] Example 1

[0075] The purpose of this embodiment is to determine whether the displacement experiment of simulating formation water displacement is completed. When the displacement is completed, the oil volume in the electronic measuring cylinder 35 will remain stable; please refer to Figure 1 、 2 3. An intelligent core displacement experimental device, comprising a drying box 11, a core geometric parameter measuring device, a constant temperature box 10, a displacement device and a computer device 16;

[0076] Step 1: Select a core 23 and place the core 23 in the drying box 11 for drying;

[0077] Step 2: Place the dried core 23 into the core holder 22 of the constant temperature box 10;

[0078] Step 3: Rotate the valve core of the six-way valve 1-14, select the intermediate container 2-18, use simulated oil drive, turn on the horizontal flow pump 13 to pump the water in the water container 12 into the lower part of the piston 20 in the intermediate container 2-18, push the piston 20 upward, and pressurize the simulated formation water in the intermediate container 2-18 to the core holder 22;

[0079] Step 4: The displacement is continued until the dried core 23 is saturated with simulated oil, and the advection pump 13 is turned off;

[0080] Step 5: Rotate the valve core of the six-way valve 1-14, select the intermediate container 1-17, use simulated formation water drive, turn on the horizontal flow pump 13, pump the water in the water container 12 into the lower part of the piston 20 in the intermediate container 1-17, push the piston 20 upward, and pressurize the simulated formation water in the intermediate container 1-17 to the core holder 22;

[0081] Step 6: As displacement time increases, simulated oil and simulated formation water appear in the electronic graduated cylinder 35. The electronic graduated cylinder 35 and the capacitive crude oil water content online measuring device 34 measure the volume of simulated formation water and simulated oil, as well as the water content in real time. The data is transmitted to the computer device 16 in real time for aggregation, calculation, and judgment.

[0082] The calculation formula of the oil-containing volume is:

[0083] Oil content volume = oil content × total liquid volume

[0084] Wherein, the oil content is the oil content in the electronic graduated cylinder 35, and the calculation formula of the oil content is:

[0085] Oil content = 1-water content

[0086] Wherein, water content is the water content measured in real time by the capacitive crude oil water content online measuring device 34;

[0087] When the computer device 16 calculates the oil volume in the electronic measuring cylinder 35 in real time in the above manner and the value remains stable, it indicates that the displacement is completed;

[0088] Example 2

[0089] The purpose of this second embodiment is to calculate the recovery rate of simulated formation water flooding, draw the relationship curve between the pressure difference and flow rate of the fluid passing through the core, and then calculate the absolute permeability of the fluid and the possible starting pressure gradient, and calculate the relative permeability of the oil and water phases, and draw the oil and water phase relative permeability curve. Figure 1 、 2 3. An intelligent core displacement experimental device, comprising a drying box 11, a core geometric parameter measuring device, a constant temperature box 10, a displacement device and a computer device 16;

[0090] Step 1: Select a core 23, place the core 23 in the drying oven 11 for drying, and measure the mass m of the core 23 after drying. 干 , radius r, height h, place the dried core 23 into the core holder 22 of the thermostat 10;

[0091] Step 2: Rotate the valve core of the six-way valve 1-14, select the intermediate container 1-17, use simulated formation water flooding, turn on the horizontal flow pump 13 to pump the water in the water container 12 into the intermediate container 1-17 below the piston 20, push the piston 20 upward, and pressurize the simulated formation water in the intermediate container 1-17 to the core holder 22. The flooding is continued until the dried core 23 is saturated with the simulated formation water. Turn off the horizontal flow pump 13, and the flow meter 37 transmits the flow rate Q to the computer device 16 in real time. The computer device 16 calculates the real-time flow rate using the formula:

[0092]

[0093] Where Q is the flow rate measured by the flowmeter; A is the cross-sectional area of the pipe; r is the radius of the pipe; v w is the water flow rate;

[0094] Step 3: The computer device 16 calculates the porosity of the core 23 using the formula:

[0095]

[0096] Where V 岩 is the core volume; φ is the porosity of the core; V w is the volume of water entering the core, and the formula is:

[0097] V w =v w ×tV 量简 -V 前管 -V 后管

[0098] Where, v w , is the water flow rate; t is the time; V 量筒 is the volume of water in the measuring cylinder; to improve accuracy, the volume of water in the pipes before and after the core holder is also subtracted V 前管 、V 后管 , where relevant pipeline parameters can be input into the computer equipment during installation;

[0099] The computer device 16 calculates the porosity of the core 23 and then calculates the pore volume of the core 23 using the following formula:

[0100] V 孔 =V 岩 ×φ

[0101] Where V 孔 is the pore volume of the core; V 岩 is the core volume; φ is the porosity of the core;

[0102] Step 4: Rotate the valve core of the six-way valve 1-14, select the intermediate container 2-18, use simulated oil drive, turn on the horizontal flow pump 13, pump the water in the water container 12 into the lower part of the piston 20 in the intermediate container 2-18, push the piston 20 upward, and send the simulated oil pressure in the intermediate container 2-18 to the core holder 22;

[0103] Step 5: The displacement is continued until the computer device 16 calculates that the water volume in the electronic graduated cylinder 35 is maintained in a stable state. The simulated oil displacement experiment is ended, and the horizontal flow pump 13 is turned off. The computer device 16 obtains the volume V of the simulated formation water displaced by the oil displacement simulated formation water. 水 The computer device 16 calculates the bound water saturation S wi , the formula is:

[0104] S wi =V 孔 -V 水

[0105] Where S wi is the bound water saturation; V 孔 is the pore volume of the core; V 水 is the volume of water displaced by oil after the core is saturated with water;

[0106] Step 6: Rotate the valve core of the six-way valve 1-14, select the intermediate container 1-17, and use simulated formation water flooding. At this time, the core 23 contains both simulated formation water and simulated oil. Turn on the horizontal flow pump 13 to pump the water in the water container 12 into the intermediate container 1-17 below the piston 20, push the piston 20 upward, and pressurize the simulated formation water in the intermediate container 1-17 to the core holder 22.

[0107] Step 7: The displacement is continued until the computer device 16 calculates that the oil volume in the electronic graduated cylinder 35 is maintained at a stable state. The simulated formation water flooding experiment is completed, and the horizontal flow pump 13 is turned off. The computer device 16 obtains the volume V of the simulated oil displaced by the simulated formation water. 油1 The computer device 16 calculates the simulated formation water flooding end, the remaining simulated oil volume V in the core or , the formula is:

[0108] V or =V 水1 -V 油1

[0109] Where V 油1 V is the volume of simulated oil displaced from the core saturated with oil and water by flooding with simulated formation water; or V is the volume of simulated oil remaining in the core at the end of simulated formation water displacement;水1 The volume of simulated formation water displaced by the simulated oil in the core saturated with simulated formation water is given by:

[0110] V 水1 =V 孔 (1-S wi )

[0111] Where V 孔 is the pore volume of the core; S wi is the bound water saturation;

[0112] Step 8: The computer device 16 calculates the residual oil saturation S at the end of the simulated formation water flooding. or , the formula is:

[0113]

[0114] Where V or V is the volume of simulated oil remaining in the core at the end of simulated formation water displacement; 孔 is the pore volume of the core; S or It is the residual oil saturation at the end of simulating formation water displacement.

[0115] The computer device calculates the simulated oil recovery factor η using the formula:

[0116]

[0117] Where S or is the residual oil saturation; S wi is the irreducible water saturation; η is the simulated oil recovery factor;

[0118] Step 9: The computer device 16 plots a relationship curve between the pressure difference ΔP between the front and rear ends of the fluid passing through the core and the flow rate Q of the fluid passing through the core, and calculates the absolute permeability k of the fluid and the possible starting pressure gradient;

[0119] Step 10: The computer device 16 calculates the relative permeability of the oil-water two-phase and draws the oil-water two-phase relative permeability curve. The formula is:

[0120]

[0121] Where S wi is the bound water saturation; S w is the water saturation, and the formula is:

[0122]

[0123] Where V 孔 is the pore volume of the core; V 岩油is the volume of oil in the core, and the formula is:

[0124] V 岩油 =V 总油 -V 量液 ×(1-W 量 )

[0125] Where V 总油 V is the total oil volume in the core before water flooding; 量液 W is the total volume of liquid in the measuring cylinder; 量 The water content in the graduated cylinder is measured by a capacitive crude oil water content online measuring device;

[0126] According to different rock types, select different empirical formulas for oil-water relative permeability in the table:

[0127]

[0128] Example 3

[0129] The purpose of this embodiment 3 is to calculate the recovery rate of simulated ion water flooding, draw the relationship curve between the pressure difference and flow rate of the fluid passing through the core, and then calculate the absolute permeability of the fluid and the possible starting pressure gradient. Figure 1 、 2 3. An intelligent core displacement experimental device, comprising a drying box 11, a core geometric parameter measuring device, a constant temperature box 10, a displacement device and a computer device 16;

[0130] Step 1: Select a core 23, place the core 23 in the drying box 11 for drying, and measure the mass m of the core 23 after drying. 干 , radius r, height h, place the dried core 23 into the core holder 22 of the thermostat 10;

[0131] Step 2: Rotate the valve core of the six-way valve 1-14, select the intermediate container 1-17, use simulated formation water flooding, turn on the horizontal flow pump 13 to pump the water in the water container 12 into the intermediate container 1-17 below the piston 20, push the piston 20 upward, and pressurize the simulated formation water in the intermediate container 1-17 to the core holder 22. The flooding is continued until the dried core 23 is saturated with the simulated formation water. Turn off the horizontal flow pump 13, and the flow meter 37 transmits the flow rate Q to the computer device 16 in real time. The computer device 16 calculates the real-time flow rate using the formula:

[0132]

[0133] Where Q is the flow rate measured by the flowmeter; A is the cross-sectional area of the pipe; r is the radius of the pipe; v w is the water flow rate;

[0134] Step 3: The computer device 16 calculates the porosity of the core 23 using the formula:

[0135]

[0136] Where V 岩 is the core volume; φ is the porosity of the core; V w is the volume of water entering the core, and the formula is:

[0137] V w =v w ×tV 量筒 -V 前管 -V 后管

[0138] Where, v w is the water flow rate; t is the time; V 量筒 is the volume of water in the measuring cylinder; to improve accuracy, the volume of water in the pipes before and after the core holder is also subtracted V 前管 、V 后管 , where relevant pipeline parameters can be input into the computer equipment during installation;

[0139] The computer device 16 calculates the porosity of the core 23 and then calculates the pore volume of the core 23 using the following formula:

[0140] V 孔 =V 岩 ×φ

[0141] Where V 孔 is the pore volume of the core; V 岩 is the core volume; φ is the porosity of the core;

[0142] Step 4: Rotate the valve core of the six-way valve 1-14, select the intermediate container 2-18, use simulated oil drive, turn on the horizontal flow pump 13, pump the water in the water container 12 into the lower part of the piston 20 in the intermediate container 2-18, push the piston 20 upward, and send the simulated oil pressure in the intermediate container 2-18 to the core holder 22;

[0143] Step 5: The displacement is continued until the computer device 16 calculates that the water volume in the electronic graduated cylinder 35 is maintained at a stable state. The simulated oil displacement experiment is ended, and the horizontal flow pump 13 is turned off. The computer device 16 obtains the volume V of the simulated formation water displaced by the oil displacement simulated formation water. 水 The computer device 16 calculates the bound water saturation S wi , the formula is:

[0144] S wi =V 孔 -V 水

[0145] Where S wi is the bound water saturation; V 孔 is the pore volume of the core; V 水 is the volume of water displaced by oil after the core is saturated with water;

[0146] Step 6: Rotate the valve core of the six-way valve 1-14, select the intermediate container 3-19, and use simulated ion water flooding. At this time, the core 23 contains both simulated formation water and simulated oil. Turn on the horizontal flow pump 13 to pump water from the water container 12 into the intermediate container 3-19 below the piston 20, push the piston 20 upward, and pressurize the simulated ion water in the intermediate container 3-19 to the core holder 22.

[0147] Step 7: The displacement is continued until the computer device 16 calculates that the oil volume in the electronic graduated cylinder 35 is maintained at a stable state. The simulated ion water flooding experiment is completed, and the advection pump 13 is turned off. The computer device 16 obtains the volume V of the simulated oil displaced by the simulated ion water. 油1 The computer device 16 calculates the simulated ion water flooding at the end of the remaining simulated oil volume V in the core or , the formula is:

[0148] V or =V 水 1-V 油1

[0149] Where V 油1 V is the volume of simulated oil displaced from a core saturated with oil and water by simulated ion water flooding; or V is the volume of simulated oil remaining in the core at the end of simulated ion water flooding; 水1 The volume of simulated formation water displaced by the simulated oil in the core saturated with simulated formation water is given by:

[0150] V 水1 =V 孔 (1-S wi )

[0151] Where V 孔 is the pore volume of the core; S wi is the bound water saturation;

[0152] Step 8: The computer device 16 calculates the residual oil saturation Sor at the end of the simulated ion water flooding, using the formula:

[0153]

[0154] Where V or V is the volume of simulated oil remaining in the core at the end of simulated ion water flooding;孔 is the pore volume of the core; S or It is the residual oil saturation at the end of ion water flooding simulation.

[0155] The computer device calculates the simulated oil recovery factor η using the formula:

[0156]

[0157] Where S or is the residual oil saturation; S wi is the irreducible water saturation; η is the simulated oil recovery factor;

[0158] Step 9: The computer device 16 plots a relationship curve between the pressure difference ΔP between the front and rear ends of the fluid passing through the core and the flow rate Q of the fluid passing through the core, and calculates the absolute permeability k of the fluid and the possible starting pressure gradient;

[0159] The present invention solves the problems existing in core displacement experiments, such as "the displacement experiment is separated from the drying and geometric measurement links, the data needs to be manually sorted, and then indirectly calculated by combining empirical formulas, which is inefficient". The device of the present invention has the characteristics of close connection between various functional modules, automatic data association, low error, high measurement accuracy and degree of automation. It can calculate the recovery rate of water-driven oil, draw the relationship curve between the pressure difference and flow rate of the fluid through the core, and then calculate the absolute permeability of the fluid and the possible starting pressure gradient, as well as calculate the relative permeability of the oil and water phases and draw the oil-water relative permeability curve.

[0160] The above description is merely an embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An intelligent core displacement experimental device, comprising a drying box, a core geometric parameter measuring device, a constant temperature box, a displacement device and a computer device, wherein the displacement device is composed of a water container, a horizontal flow pump, a six-way valve 1, a six-way valve 2, a pressure gauge 1, a pressure gauge 2, a pressure gauge 3, an intermediate container 1, an intermediate container 2, an intermediate container 3, a flow meter, a core, a core holder, a back pressure valve, an electronic measuring cylinder and a capacitive crude oil water content online measuring device; the inlet end of the horizontal flow pump is connected to the water container through a pipeline to pump water into the bottom of the piston of the intermediate container; the six-way valve 1 is connected to three intermediate containers containing different displacement fluids, and the six-way valve 1 is connected to the pressure gauge 1; the flow meter is connected to the six-way valve 2 through a pipeline for measuring the liquid flow at the inlet end of the core holder; the core holder is used to support the core to be displaced, and the inlet end of the core holder is connected to the six-way valve 2 through a pipeline and then connected to the pressure gauge 2 for real-time measurement of the pressure at the inlet end of the core holder; the back pressure valve A valve is connected to the rear end of the core holder via a pipeline to reduce the pressure at the core holder outlet, and the rear end of the back-pressure valve is connected to a pressure gauge 3. The electronic graduated cylinder is connected to the rear end of the pressure gauge 3 via a pipeline to measure the height and volume of the expelled liquid in real time, and the electronic graduated cylinder is also connected to a computer device. The capacitive online measurement device for the water content in crude oil is inserted into the electronic graduated cylinder, and the probe is in close contact with the bottom surface of the electronic graduated cylinder. The capacitive online measurement device for the water content in crude oil is also connected to the computer device. The computer device is connected to the pressure gauge, the electronic graduated cylinder, the drying box control panel, the constant temperature box control panel, and the capacitive online measurement device for the water content in crude oil, and is used to obtain the transmitted real-time measurement data and calculate the recovery rate, draw a relationship curve between the pressure difference and flow rate of the fluid passing through the core, and then calculate the absolute permeability of the fluid and the possible starting pressure gradient, as well as calculate the relative permeability of the oil and water phases and draw an oil-water relative permeability curve.

2. The intelligent core flooding experimental device according to claim 1 is characterized in that The thermostat is used to simulate formation temperature. An observation window is provided on the door of the thermostat for observing the internal state of the thermostat during the displacement experiment. A groove-shaped handle is also provided for opening and closing the door. The measuring devices in the thermostat and drying box will send the measured data to the computer equipment in real time through the computer control panel for relevant calculations.

3. The intelligent core flooding experimental device according to claim 1 is characterized in that The core holder is placed inside a constant temperature box to ensure that the displacement experiment is carried out at a simulated formation temperature; the inlet end of the core holder is connected to a six-way valve 2 through a pipeline and then to a pressure gauge 2 for real-time measurement of the pressure at the inlet end of the core holder and transmitting the data to a computer device in real time; the core to be displaced is placed in the middle of the core holder; the outlet end of the core holder is connected to a back pressure valve through a pipeline to reduce the outlet pressure of the core holder.

4. The intelligent core flooding experimental device according to claim 1, characterized in that The electronic graduated cylinder transmits the height and volume of the displaced liquid measured in real time to a computer device for use in calculating the recovery rate. The capacitive crude oil water content online measuring device is inserted into the electronic graduated cylinder, with the probe in close contact with the bottom surface of the electronic graduated cylinder, to measure the water saturation of the displaced liquid in the electronic graduated cylinder. At the same time, the capacitive crude oil water content online measuring device transmits the data to the computer device in real time, which is combined with the data from the electronic graduated cylinder to determine whether the displacement is complete and used for calculation of the recovery rate, the relative permeability of the oil and water phases, and the absolute permeability of the fluid.

5. The intelligent core flooding experimental device according to claim 1, characterized in that A method for determining whether the displacement is complete is provided in a displacement experiment based on the above-mentioned displacement device. The method comprises: the computer device receives real-time data transmitted from an electronic graduated cylinder and a capacitive crude oil water content online measurement device, summarizes, calculates, and determines that when the displacement is complete, the oil volume in the electronic graduated cylinder will remain stable. When the computer device calculates in real time through the above method that the value of the oil volume in the electronic graduated cylinder remains in a stable state, it indicates that the displacement is complete.

6. The intelligent core flooding experimental device according to claim 1, characterized in that A method for calculating the recovery factor and absolute fluid permeability based on the displacement experiment of the above displacement device is provided: Step 1: Select a core, place the core in a drying oven to dry it, and measure the mass, radius, and height of the core after drying; Step 2: Rotate the valve core of six-way valve 1, select intermediate container 1, and use simulated formation water flooding. Continue flooding until the dried core is saturated with simulated formation water. At this time, the water flow rate per unit time into the electronic graduated cylinder remains stable within a certain range. The flow meter transmits the flow rate in real time to the computer equipment through the computer control panel of the constant temperature box. The computer equipment calculates the real-time flow rate and the porosity of the core, and then calculates the pore volume of the core. Step 3: Rotate the valve core of the six-way valve 1, select the intermediate container 2, and use simulated oil flooding. The flooding is carried out until the computer equipment calculates that the water volume in the electronic graduated cylinder remains in a stable state. The simulated oil flooding experiment ends, and the computer equipment obtains the volume of water displaced by the oil flooding and calculates the irreducible water saturation. Step 4: Rotate the valve core of the six-way valve 1, select the intermediate container 1, and use simulated formation water drive. At this time, there are both simulated formation water and simulated oil in the core. The drive is carried out until the computer device calculates that the oil volume in the electronic measuring cylinder is maintained in a stable state. The simulated formation water drive experiment is completed, and the computer device obtains the volume of simulated oil driven out by the simulated formation water; the computer device calculates the volume of simulated oil remaining in the core at the end of the simulated formation water drive, the residual oil saturation and the recovery rate of the simulated oil, draws a relationship curve between the pressure difference ΔP at the front and rear ends of the fluid passing through the core and the flow rate Q of the fluid through the core, and calculates the absolute permeability k of the fluid and the possible starting pressure gradient.

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