Testing device and measuring method for measuring chemical oil displacement characteristics of full-size shaft

Abstract

The invention belongs to the technical field of oil displacement dynamic physical simulation experiments of different displacement media in chemical oil displacement oil extraction of an oil field, and discloses a testing device and a measuring method for measuring chemical oil displacement characteristics of a full-size shaft, and the testing device comprises three wells (1 injection and 2 production), an artificial core, a perforation core ring, a core constant-temperature heating device, a core ring pressure co-supplying device and the like. The method comprises the following steps: putting a columnar artificial rock core, adding a perforation rock core ring outside an injection shaft, enabling perforation positions of the perforation rock core ring and the injection shaft to correspond one by one, installing an injection-production well, drilling a sampling hole, and lowering a sampler from a sampling pipe; injecting water and oil from the injection well to saturate the columnar artificial core; increasing the pressure and temperature in the device to a design value through pressurizing and heating; injection liquid is injected from the injection well, when the pressure of the sampling hole is obviously changed, sampling is carried out, and the composition and performance of a sample are analyzed. Chemical flooding oil displacement physical simulation experiments under different perforation modes of a full-size borehole are carried out, and the oil-water movement rule and the remaining oil distribution condition of a chemical flooding stratum are determined.

Description

Technical Field

[0001] The invention relates to the technical field of dynamic physical simulation experiments on oil recovery by different displacement media in oilfield chemical recovery, and in particular to a testing device and a method for measuring chemical recovery characteristics of a full-size wellbore. Background Art

[0002] At present, in the later stage of exploitation of medium and high permeability sandstone reservoirs, it is necessary to mix polymers, surfactants, alkali and other chemical reagents in a certain proportion to form a target fluid, and then inject the target fluid into the formation for oil recovery, thereby increasing the oil recovery efficiency and swept volume to obtain a higher recovery rate.

[0003] During the chemical flooding development stage, the viscosity and concentration of the injection fluid have a great influence on the oil recovery effect. How to optimize the injection fluid formula system and clarify the performance of the injection fluid at different injection locations such as in the wellbore, perforation, and formation are the main controlling factors for the success of chemical flooding development.

[0004] The existing indoor test equipment can only simulate the chemical flooding effect of small size and single influencing factor. The wellbore, perforation, and displacement and impact conditions in the layer cannot be effectively or uniformly tested, resulting in a large difference between the actual reservoir conditions and the injection fluid formula system when evaluating the injection fluid formula system. During the field implementation, it is necessary to continuously adjust the injection fluid formula system according to the development dynamic characteristics to explore the best injection fluid system and improve the chemical flooding effect of the oil field. As a result, a large amount of chemical agents are wasted due to multiple adjustments to the appropriate formula system during the chemical flooding development process, which increases the cost of chemical flooding development. At the same time, the overall performance of the injection fluid is greatly reduced due to wear and diameter change in the wellbore and perforation, which will also reduce the chemical flooding development effect. The indoor test uses a small-scale displacement test, which results in the inability to effectively measure key development indicators such as the displacement front morphology and the distribution of residual oil in the chemical flooding layer. It is difficult to clarify the effect of chemical flooding in different reservoirs and the residual potential of chemical flooding, resulting in the inability to fully realize the potential of chemical flooding development in oil fields. Summary of the invention

[0005] In view of the shortcomings of existing chemical flooding laboratory test technology, the purpose of the present invention is to provide a test device and a measurement method for measuring the chemical flooding characteristics of a full-size wellbore.

[0006] A further purpose of the present invention is to optimize the chemical flooding scheme by testing the changes in the performance of the injection fluid in different parts, selecting the wellbore and perforation method suitable for chemical flooding development, and determining indicators such as the displacement speed, the swept range, and the remaining oil distribution.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A testing device for measuring chemical oil recovery characteristics of a full-size wellbore, wherein an insertable open steel pipe is arranged in the center as an injection well, and two insertable open steel pipes are arranged on the sides as production wells 1 and 2. The device may also include: a columnar artificial core, a columnar artificial core sleeve, a perforated core ring, a core constant temperature heating device, a core ring pressure supply device, a sampling tube with a top cover, a metal fixing block, and a bottom support frame of the device.

[0009] The injection well is located in the middle of the device, and the two production wells are located on both sides of the device, with the same distance from the injection well. The distance L5 between injection well 1 and the production well is 5m. The injection well is loaded with a diameter L1 of 139.7mm full-size casing. The injection well casing is opened on both sides of the core section, and the hole diameter is 8mm to 16mm. The hole diameters on both sides can be equal or different according to measurement requirements. Production wells 1 and 2 are only opened on the side facing the core, and the hole diameters are 8mm to 16mm.

[0010] The perforation core ring outside the injection well has a thickness of 30cm, and its main function is to simulate different downhole perforation modes such as perforation size, hole volume, and whether to perforate with equal diameter. At present, in the downhole perforation process, the conventional perforating bullet cannot perforate in the center due to the bending change of the wellbore trajectory, so the hole diameter and hole volume are large at the end close to the perforating gun, and the hole diameter and hole volume are small at the end far from the casing; for the improved equal-aperture perforating bullet, the perforation shape changes from the previous near-conical shape to the near-cylindrical cone shape. The above perforation mode leads to different perforation diameters, hole volumes, and perforation shapes, such as Figure 2 The opening of the perforated core ring is corresponding to the opening of the injection well and the corresponding hole size is equal. The opening diameter is 8mm to 16mm. Different combinations of hole diameters, pore volumes, and perforation forms can be produced. The perforated core ring can be fully perforated or partially perforated.

[0011] The columnar artificial core has a length of 470 cm and a radius of 40 to 150 cm. It is precast with artificial sand and has a single-side core length. A layered casting mode is usually adopted, that is, it is divided into multiple layers from top to bottom vertically. Different permeabilities can be set for each layer to simulate the vertical differences of the formation.

[0012] The core constant temperature heating device is used to heat the entire core to ensure that the temperature of the columnar artificial core and the fluid inside it can be the same as the formation temperature during testing.

[0013] The function of the core ring pressure co-supply device is to heat and maintain the pressure of the core to ensure that the pressure of the columnar artificial core and its internal fluid can be the same as the formation pressure during the test. By adding pressurized fluid inside it to give pressure to its inner liner, the liner transmits the confining pressure to the columnar artificial core sleeve and the columnar artificial core inside the test device, thereby adding confining pressure to them.

[0014] The length of the columnar artificial core sleeve is less than 470 cm, and it is sleeved on the outside of the columnar artificial core to ensure that columnar artificial cores 5 of different radii can be filled with the test device through the columnar artificial core sleeve. One side of the columnar artificial core sleeve is close to the core ring pressure supply device, and the other side is close to the columnar artificial core.

[0015] The sampling tube with a top cover can export fluids from different parts for sampling and analysis. Its aperture is 0.3cm, and the fluid is exported through an equal-diameter flow-guiding steel pipe for testing and analysis. A sampling hole is set in the middle of the injection well and the production well; a sampling hole is set at each of the left and right perforation cavities of the perforated core ring; sampling holes are set in rows at the columnar artificial cores on the left and right sides, with each row 30cm away from L4, and 25 sampling holes are set in each row evenly distributed on the columnar artificial core. The depth of each row of sampling points into the columnar artificial core is set to 10cm, 20cm, and 30cm, with different depths in the center, and 8 points at each depth, to ensure that the sampling points in the same row at different depths are evenly distributed on the columnar artificial core.

[0016] The metal fixing block is placed on the outside of the unperforated end of the production well. It can transmit pressure and temperature and is generally prefabricated with a metal block.

[0017] A method for measuring the characteristics of chemical flooding in a full-scale wellbore, characterized in that it comprises the following steps:

[0018] S01 puts in a columnar artificial core, adds a perforated core ring outside the injection wellbore, and the perforations of the two correspond one by one. The injection well, production well 1, and production well 2 are installed;

[0019] S02. Inject water and oil from the injection well to saturate the columnar artificial core;

[0020] S03 raises the pressure and temperature in the device to the designed value by pressurizing and heating;

[0021] S04 injects the injection liquid from the injection well. When there is an obvious pressure change in the sampling hole, open the sampling hole to take samples and analyze the composition and performance of the samples.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. Capable of measuring full-scale wellbore chemical flooding oil recovery characteristics.

[0024] 2. It can simulate the influence of different perforation conditions on the performance of injection fluid, including equal aperture and equal pore volume perforation, aperture difference perforation, the aperture and density can be adjusted, the casing and perforation core ring can be flexibly disassembled and replaced, and can be quickly switched to carry out experimental analysis. The disassembled casing and perforation core ring can be reused to save costs.

[0025] 3. The measuring device is equipped with pressurization and heating devices, which can simulate chemical flooding experiments under different pressures and temperatures, and can better correspond to the underground conditions of the reservoir in the field experiment.

[0026] 4. Injection fluid sampling devices are installed at the bottom of the injection well and the production well, the perforation cavity of the perforated core ring, and the displacement core, which can measure the performance of the injection fluid at different positions. At the same time, the position of the chemical drive front and the distribution of the remaining oil can also be recorded in time on the displacement core, which is a significant improvement over the single-factor measurement of existing indoor test devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0028] Figure 1 A schematic diagram of the side reference structure of the testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to the present invention;

[0029] Figure 2 It is a cross-sectional structural diagram of the structure of the testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to the present invention;

[0030] Figure 3 is a schematic diagram of the reference structure of the perforated core ring of the present invention;

[0031] Figure 4 The present invention is a flow chart of the method for measuring characteristics of chemical flooding oil recovery.

[0032] Among them: 1-bottom support frame of the device; 2-core constant temperature heating device; 3-core ring pressure supply device; 4-perforated core ring; 5-columnar artificial core; 6-sampling hole; 7-metal fixing block; 8-columnar artificial core sleeve; 9-sampling tube with top cover; 10-sampler; 11-upper connection locker; 12-lower connection locker; 13-conical perforation cavity in the perforated core ring; 14-columnar cone perforation cavity in the perforated core ring; 15-sampling hole on the left side of the perforated core ring; 16-sampling hole on the right side of the perforated core ring; h1-diameter of the perforation hole on the left side of the perforated core ring; h2-diameter of the perforation hole on the right side of the perforated core ring; h3-diameter of the columnar artificial core; L1-diameter of the injection well and the production well; L2-depth of the perforation cavity on the left side of the perforated core ring; L3-depth of the perforation cavity on the right side of the perforated core ring; L4-row spacing between two adjacent rows of fluid sampling points on the columnar core; L5-well spacing between the injection well and the production well. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical scheme of the present invention is now described in detail in conjunction with the following specific embodiments, but it should not be understood as limiting the scope of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the equipment used can be obtained from commercial channels.

[0034] Example 1

[0035] A test device for measuring chemical oil flooding characteristics of a full-size wellbore, wherein the tank body is connected by an upper connecting locker 11 and a lower connecting locker 12, and is characterized in that an open steel pipe that can be inserted is arranged in the center thereof as an injection well, and two open steel pipes that can be inserted are arranged on the edge, as production well 1 and production well 2, the distance between production well 1 and the injection well, and the distance between production well 2 and the injection well are both L5, the injection well casing is opened on both sides of the core section, a perforated core ring 4 is inserted on the outside of the injection well, one side of the columnar artificial core 5 is tightly fitted with the production well 1 or the production well 2, and the other side is tightly fitted with the perforated core ring 4, and the injection well and the production well are connected at the injection well and the production well. A sampling point is set in the middle; an injection fluid sampling point is set at each of the left and right perforation cavities of the perforated core ring 4; sampling holes 6 are arranged in rows at the columnar artificial cores 5 on the left and right sides, and the distance between each row and L4 is 30 cm. 25 sampling holes 6 are set in each row and are evenly distributed on the columnar artificial core 5. The depth of each row of sampling holes 6 into the columnar artificial core 5 is set to different depths of 10 cm, 20 cm, and 30 cm, with 8 points at each depth. Each sampling hole 6 is equipped with a sampling tube 9 with a top cover and a sampler 10. The metal fixing block 7 is placed on the outside of the unperforated end of the production well. The outer wall of the test device is provided with a core ring pressure supply device 3 and a core constant temperature heating device 2 in sequence.

[0036] like Figure 1-4 As shown, the measurement process is as follows:

[0037] 001. Make a core of a size suitable for a full-scale wellbore chemical flooding characteristic test device, ensuring that 3-5 layers of reservoirs with different permeabilities are distributed vertically;

[0038] 002. Open the upper connection locker 11 and the lower connection locker 12 on one side of the test device, open the test equipment, and place the columnar artificial core 5 into the test device. If the radius of the columnar artificial core 5 reaches 150 cm, it indicates that the test core can fill the test equipment, and the columnar artificial core 5 is directly placed therein; if the size of the columnar artificial core 5 is less than 150 cm, add a columnar artificial core sleeve 8 to its outside to ensure that the inner side of the columnar artificial core sleeve 8 and the columnar artificial core 5 fit tightly, and the outer diameter of the sleeve reaches 150 cm to ensure that its outer side fits tightly with the test device. Open the sampling tube 9 with a top cover outside the equipment, drill holes from the sampling tube 9 with a top cover to the columnar artificial core sleeve 8 and the columnar artificial core 5, drill to the sampling point, and insert a liquid sampling tube with a pressure and temperature sensor on the top from the sampling tube 9 with a top cover. The sampling tube extends from the top cover, and the sampling tube top cover is closed to ensure that no liquid is exposed;

[0039] 003. After installing the columnar artificial core 5 on one side, drill a hole that can accommodate a full-size casing with an outer diameter of 139.7 mm from the position of the simulated production well on one side, and add a simulated production well steel pipe with a single-side opening;

[0040] 004. According to the test requirements, suitable openings are made on the perforated core ring 4 to meet the perforation morphology simulation requirements, the perforated core ring is placed in the test equipment to ensure that it is located at the center of the equipment, the casing of the simulated injection well is opened on both sides as required and inserted into the perforated core ring 4, and the sampling tube 9 with a top cover is lowered from the sampling tube outside the equipment using the core sampling point lowering method;

[0041] 005. Add the columnar artificial core 5 on the other side, drill a hole and lower the steel pipe on the other side to simulate the production well at the other end, drill a sampling hole 6 in the core and lower the sampling tube 9 with a top cover;

[0042] 006. Close the test device, and connect the upper locking device 11 and the lower locking device 12 to ensure that the test device is sealed;

[0043] 007. Inject water from the injection well. After the columnar artificial core 5 is saturated with water, inject oil sample from the injection well to drive water, saturate the columnar artificial core 5 with the oil sample, and finally adjust the oil saturation in the core to the designed oil saturation by injecting water from the injection well;

[0044] 008. The columnar artificial core 5 is pressurized and heated by the core constant temperature heating device 2 and the core annular pressure supply device 3, and the columnar artificial core 5 and the fluid are raised to the designed pressure and temperature;

[0045] 009. Inject the chemical flooding injection fluid from the injection well, monitor the pressure change at different sampling holes 6, and when there is a significant pressure change, open the sampling hole 6 to take samples, analyze the composition and performance of the samples, so as to determine the performance change of the injection fluid in the wellbore; infer the performance change of the injection fluid passing through the perforations through different perforation densities, apertures, pore volumes, perforation morphologies, etc.; the performance change of the injection fluid at different positions in the core; the performance status of the produced fluid in the production well;

[0046] After a set of tests is completed, a new test can be carried out by simply changing the core ratio to the oil and water form under the initial condition. There is no need to replace the columnar artificial core 5 for each test. At the same time, different perforated casings of the injection well and the corresponding perforated core rings 4 can be recycled, thereby effectively reducing the testing cost.

[0047] The device of the present invention can carry out different injection liquid chemical agent ratios, and its oil displacement status comparison test, and optimize the best chemical flooding injection system and injection and production parameters. Further, different perforation density, pore size, pore volume, perforation morphology, and injection liquid property loss comparison tests can be carried out to optimize the best perforation scheme. Further, the flow characteristics and seepage characteristics of chemical flooding between injection wells and production wells can be clarified, and the oil-water movement law and residual oil enrichment characteristics and areas of chemical flooding reservoirs can be clarified.

[0048] The above description is only an illustrative preferred embodiment of the present invention and does not impose any limitation on the present invention. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A test device for measuring the characteristics of chemical oil displacement in a full-scale wellbore, wherein the tank body is connected by an upper connecting locker (11) and a lower connecting locker (12), characterized in that: An insertable open steel pipe is arranged at the center as an injection well, and two insertable open steel pipes are arranged at the edge as production well 1 and production well 2. The distance between production well 1 and injection well, and the distance between production well 2 and injection well are both L5. The injection well casing is perforated on both sides of the core section. A perforated core ring (4) is inserted into the outside of the injection well. One side of the columnar artificial core (5) is tightly fitted with production well 1 or production well 2, and the other side is tightly fitted with the perforated core ring (4). A sampling point is arranged in the middle of the injection well and the production well; and a sampling hole (6) is arranged at each of the left and right perforation cavities of the perforated core ring (4). Sampling holes (6) are arranged in rows at the columnar artificial cores (5) on the left and right sides, with a distance L4 of 30 cm between each row. 25 sampling holes (6) are arranged in each row and are evenly distributed on the columnar artificial core 5. The depth of each row of sampling holes (6) into the columnar artificial core (5) is set to different depths of 10 cm, 20 cm, and 30 cm, with 8 points at each depth. Each sampling hole (6) is equipped with a sampling tube (9) with a top cover and a sampler (10). A metal fixing block (7) is placed on the outside of the unperforated end of the production well. The outer wall of the test device is provided with a core ring pressure supply device (3) and a core constant temperature heating device (2) in sequence.

2. The full-scale wellbore chemical flooding characteristics test device according to claim 1 is characterized in that: The columnar artificial rock core (5) is sleeved with a columnar artificial rock core sleeve (8).

3. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: A device bottom support frame (1) is provided.

4. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: The diameters of the holes opened in the injection well casing on both sides of the core section are the same or different.

5. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: L5 is 5m, the injection well's loading diameter L1 is 139.7mm full-size casing, the hole diameter is 8mm~16mm, and production wells 1 and 2 are only opened on the side facing the core, and the hole diameter is 8mm~16mm.

6. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: The core ring (4) of the hole is fully or partially perforated.

7. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: The thickness L3 of the perforated core ring (4) is 30 cm, the opening of the perforated core ring (4) corresponds to the opening of the injection well and the corresponding hole sizes are equal, and the opening diameter size is 8 mm to 16 mm.

8. The testing device for measuring the characteristics of chemical oil displacement in a full-scale wellbore according to claim 1, characterized in that: The length of the columnar artificial core (5) is 470 cm, the radius is 40-150 cm, and it is prefabricated and cast in layers using artificial sand.

9. A method for measuring the characteristics of chemical flooding in a full-scale wellbore, characterized in that: The steps include: S01: insert a columnar artificial core (5), add a perforated core ring (4) outside the injection wellbore, the perforations of the two wells correspond to each other, and install the injection well, production well 1, and production well 2; S02. Injecting water and oil from the injection well to saturate the columnar artificial core (5); S03 raises the pressure and temperature in the device to the designed value by pressurizing and heating; S04 injects the injection liquid from the injection well, and when there is an obvious pressure change in the sampling hole (6), opens the sampling hole (6) to take samples, and analyzes the composition and performance of the samples.

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