A full-size wellbore chemical oil displacement characteristic measuring device and measuring method

Abstract

The present application belongs to the technical field of oilfield chemical flooding oil displacement dynamic physical simulation experiment of different displacement medium, and discloses a kind of measuring full-size wellbore chemical flooding oil displacement characteristic testing device and measuring method, containing 3 wells (1 injection 2 production), artificial core, perforated core ring, core constant temperature heating device, core ring pressure sharing device and the like, the method includes putting into columnar artificial core, adding perforated core ring outside injection wellbore, making both perforations correspond one by one, installing injection-production well, drilling sampling hole, and lowering sampler from sampling pipe;Water and oil are injected from injection well to saturate columnar artificial core;The pressure and temperature in the device are increased to the design value by pressurizing and heating;When there is a significant pressure change in the sampling hole, sampling is performed, and the composition and performance of the sample are analyzed.The present application carries out chemical flooding oil displacement physical simulation experiment under different perforation modes of full-size wellbore to determine the oil-water movement law and remaining oil distribution of chemical flooding formation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of physical simulation experiment of oil displacement by different displacement medium in oilfield chemical flooding, in particular to a full-size wellbore chemical flooding characteristic measuring device and measuring method. BACKGROUND

[0002] At present, in the later stage of exploitation of medium-high permeability sandstone reservoir, chemical reagents such as polymer, surfactant and alkali are mixed in a certain proportion to form a target liquid, and then the target liquid is injected into the formation to displace oil, so as to increase the oil displacement efficiency and swept volume and obtain higher recovery.

[0003] In the chemical flooding development stage, the viscosity and concentration of the injected liquid have a great influence on the oil displacement effect, how to optimize the formula system of the injected liquid and determine the performance of the injected liquid at different injection positions such as wellbore, perforation and formation are the main control factors for the success of chemical flooding development.

[0004] The existing indoor test device can only simulate the chemical flooding effect of small size and single influencing factor, and the wellbore, perforation and in-layer displacement swept conditions cannot be effectively or uniformly tested, resulting in a large difference between the evaluation of the formula system of the injected liquid and the actual condition of the reservoir. In the field implementation process, the formula system of the injected liquid needs to be adjusted constantly to explore the best injected liquid system and improve the chemical flooding effect of the oilfield, which leads to a large amount of chemical reagents wasted due to the adjustment of the suitable formula system for many times in the chemical flooding development process, and increases the cost of chemical flooding development. At the same time, the overall performance of the injected liquid is greatly reduced due to the abrasion and variable diameter in the wellbore and perforation, which also reduces the effect of chemical flooding development. The small size displacement test in the indoor test leads to that the key development indexes such as the in-layer displacement front shape and remaining oil distribution condition of chemical flooding cannot be effectively measured, it is difficult to determine the effect of chemical flooding and the remaining potential of chemical flooding in different reservoirs, and the chemical flooding development of the oilfield cannot develop the full potential. SUMMARY

[0005] In view of the shortcomings of the existing chemical flooding indoor test technology, the purpose of the present application is to provide a full-size wellbore chemical flooding characteristic measuring device and measuring method.

[0006] A further purpose of the present application is to optimize the wellbore and perforation mode suitable for chemical flooding development by testing the performance change of the injected liquid at different positions, and determine indexes such as displacement speed, swept range and remaining oil distribution condition, so as to optimize the chemical flooding scheme.

[0007] To achieve the above purpose, the technical scheme of the present application is as follows:

[0008] A kind of measurement full-size wellbore chemical flooding oil characteristic testing device, a insertable open steel pipe is arranged in the center as injection well, 2 insertable open steel pipes are arranged on the side as production well 1 and production well 2, the inside of the device can also include: columnar artificial core, columnar artificial core sleeve, perforated core ring, core constant temperature heating device, core ring pressure supply device, sampling tube with top cover, metal fixing block, device bottom support frame.

[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, at the same distance from the injection well, the distance L5 between the injection well and the production well is 5 m, the injection well is filled with a full-size casing with a diameter L1 of 139.7 mm, the injection well casing is perforated on both sides of the core section, the perforation size is 8-16 mm, and the two sides can be equal or different in size according to the measurement needs. Production well 1 and production well 2 are only perforated on the side facing the core, with a perforation size of 8-16 mm.

[0010] The perforated core ring outside the injection well has a thickness L3 of 30 cm, and its main function is to simulate different perforation sizes, pore volumes, and whether the perforation is equal in diameter. In the current downhole perforation process, the conventional perforating gun bullet cannot be centered due to the bending changes of the well trajectory, resulting in a large hole diameter and large pore volume at the end close to the perforating gun, and a small hole diameter and small pore volume at the end away from the casing. For improved equal-diameter perforating gun bullets, the perforation shape changes from the previous near-conical shape to a near-cylindrical shape. The above perforation modes result in different perforation diameters, pore volumes, and perforation shapes, as shown in FIG. 1. Figure 2 The perforated core ring is made with the perforation corresponding to the injection well and the same size as the corresponding hole, with a perforation size of 8-16 mm. Different combinations of hole diameter, pore volume, and perforation shape can be made, and 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 40-150 cm. It is made of artificial sand precast and has a single-sided core length. The layered casting mode is usually used, i.e., it is divided into multiple layers from top to bottom in the vertical direction. Each layer can have different permeability to simulate the vertical difference 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 its internal fluid during testing is the same as the formation temperature.

[0013] The core ring pressure supply device is used to heat and maintain the pressure of the core to ensure that the pressure of the columnar artificial core and its internal fluid during testing is the same as the formation pressure. By adding pressure-increasing liquid to the inside of the device, the lining is pressurized. The lining transmits the confining pressure to the columnar artificial core sleeve and the columnar artificial core inside the testing device, adding confining pressure to them.

[0014] The length of the columnar artificial core sleeve is 470 cm, which is sleeved outside the columnar artificial core, and ensures that the columnar artificial cores with different radii can fill the test device through the columnar artificial core sleeve, one side of the columnar artificial core sleeve is tightly attached to the core ring pressure supply device, and the other side is tightly attached to the columnar artificial core.

[0015] The sampling tube with a top cover can guide fluids at different positions to be sampled and analyzed, and the pore diameter is 0.3 cm, and the fluid is guided out through the equal-diameter flow guide steel pipe for test analysis. A sampling hole is arranged in the injection well and the production well; one sampling hole is arranged at each of the left and right perforation cavities of the perforated core ring; sampling holes are arranged in rows at the left and right columnar artificial cores, each row is 30 cm away from L4, 25 sampling holes are arranged in each row and uniformly distributed on the columnar artificial core, and the depth of each row of sampling points into the columnar artificial core is set to 10 cm, 20 cm and 30 cm, and the center is different in depth, 8 points are arranged at each depth, and the sampling points at different depths in the same row are uniformly distributed on the columnar artificial core.

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

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

[0018] S01 Put in the columnar artificial core, add the perforated core ring outside the injection wellbore, and correspond one by one at the perforation positions of the two, and install the injection well, the production well 1 and the production well 2;

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

[0020] S03 The pressure and temperature in the device are increased to the design value by pressurization and heating;

[0021] S04 The injection fluid is injected from the injection well, when there is a significant pressure change in the sampling hole, the sampling hole is opened to take samples, and the composition and performance of the samples are analyzed.

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

[0023] 1. The chemical flooding oil displacement characteristics of a full-size wellbore can be measured.

[0024] 2. The influence of different perforation conditions on the performance of the injection fluid can be simulated, including equal-pore-diameter and equal-pore-volume perforation, pore-diameter-difference perforation, pore-diameter and pore-density adjustment, the casing and the perforated core ring can be flexibly disassembled and replaced, the experiment analysis can be quickly switched, and the disassembled casing and perforated core ring can be reused, thereby saving cost.

[0025] 3. The measuring device has a pressurizing and heat pressurizing device, which can simulate chemical flooding experiments under different pressures and temperatures, and can better correspond to the underground conditions of the field experiment reservoir.

[0026] 4. The injection fluid sampling device is arranged on the bottom of the injection well and the production well, the perforated core ring perforated cavity and the displacement core, which can measure the injection fluid performance at different positions, and can also record the chemical flooding front position and the remaining oil distribution on the displacement core in time, which is greatly improved compared with the single factor measurement of the existing indoor test device. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described below in combination with the drawings and examples.

[0028] Figure 1 It is a side reference structure diagram of the full-size wellbore chemical flooding characteristic test device of the present application;

[0029] Figure 2 It is a horizontal structure diagram of the full-size wellbore chemical flooding characteristic test device structure of the present application;

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

[0031] Figure 4 It is a flow chart of the method for measuring the chemical flooding characteristics of the present application.

[0032] Wherein: 1 - device bottom support; 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 lock; 12 - lower connection lock; 13 - conical perforated cavity in the perforated core ring; 14 - columnar perforated cavity in the perforated core ring; 15 - left sampling hole of the perforated core ring; 16 - right sampling hole of the perforated core ring; h1 - left perforated hole diameter of the perforated core ring; h2 - right perforated hole diameter of the perforated core ring; h3 - diameter of the columnar artificial core; L1 - well diameter of the injection well and the production well; L2 - left perforated cavity depth of the perforated core ring; L3 - right perforated cavity depth of the perforated core ring; L4 - distance between two adjacent fluid sampling points on the columnar core; L5 - well distance of the injection well and the production well. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application will be described in detail below in combination with the following specific examples, but it should not be understood as limiting the scope of the present application. Unless otherwise specified, the experimental methods used in the present application are conventional methods, and the equipment used can be obtained from commercial channels.

[0034] Example 1

[0035] A full-size wellbore chemical oil displacement characteristic measuring device, the tank body is connected by the upper connecting lock 11 and the lower connecting lock 12, characterized in that a insertable open steel pipe is arranged in the center as an injection well, two insertable open steel pipes are arranged on the side as production well 1 and production well 2, the distance between production well 1 and injection well, 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, the perforated core ring 4 is inserted outside the injection well, one side of the columnar artificial core 5 is closely attached to the production well 1 or the production well 2, and the other side is closely attached to the perforated core ring 4, and a sampling point is arranged in the injection well and the production well; an injection fluid sampling point is arranged at each of the left and right perforated cavities of the perforated core ring 4; a row of sampling holes 6 are arranged at the left and right columnar artificial cores 5, each row is 30 cm apart from L4, 25 sampling holes 6 are arranged in each row and 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 10 cm, 20 cm, and 30 cm at different depths, and there are 8 points at each depth, and each sampling hole 6 is equipped with a sampling tube 9 with a cap and a sampler 10, and the metal fixing block 7 is placed outside the unperforated end of the production well, and the outer wall of the testing device is sequentially provided with a core ring pressure supply device 3 and a core constant temperature heating device 2.

[0036] As shown in the figure, the measuring process is as follows: Figures 1-4

[0037] 001, make a core suitable for the size of a full-size wellbore chemical oil displacement characteristic measuring device, and ensure that it is distributed in 3-5 layers of different permeability reservoirs in the longitudinal direction;

[0038] 002, open the upper connecting lock 11 and the lower connecting lock 12 on one side of the testing device, open the testing equipment, and put the columnar artificial core 5 into the testing device, if the radius of the columnar artificial core 5 reaches 150 cm, it indicates that the testing core can fill the testing equipment, then directly put the columnar artificial core 5, if the size of the columnar artificial core 5 is less than 150 cm, add a columnar artificial core sleeve 8 outside it to ensure that the inside of the columnar artificial core sleeve 8 and the columnar artificial core 5 are closely attached, the outer diameter of the sleeve reaches 150 cm, and the outside is closely attached to the testing device. Open the sampling tube 9 with a cap outside the equipment, drill a hole from the sampling tube 9 with a cap to the columnar artificial core sleeve 8 and the columnar artificial core 5, drill to the sampling point, and lower the liquid sampling tube with a pressure and temperature sensor at the top end from the sampling tube 9 with a cap, the sampling tube extends from the cap, and the cap is closed to ensure that it does not expose liquid;

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

[0040] 004. According to the test requirements, appropriate openings are made on the perforated core ring 4 to meet the perforation shape simulation requirements. The perforated core ring is placed in the test equipment, ensuring that it is located in 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. The sampling tube 9 with a top cover is lowered from the sampling tube outside the equipment using the core sampling point 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 lock 11 and the lower lock 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 the 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. Maintaining pressure and heating the columnar artificial core 5 are applied by the core constant temperature heating device 2 and the core annular pressure supply device 3, raising both the columnar artificial core 5 and the fluid to the designed pressure and temperature;

[0045] 009. Inject the chemical flooding fluid from the injection well and monitor the pressure changes at different sampling holes 6. When there is a significant pressure change, open the sampling hole 6 to take samples and analyze the composition and properties of the samples. This allows us to determine the performance changes of the injection fluid in the wellbore. By using different perforation density, aperture, pore volume, and perforation morphology, we can infer the performance changes of the injection fluid passing through the perforations. We can also infer the performance changes of the injection fluid at different locations in the core. We can also infer the performance status of the produced fluid in the production well.

[0046] After a set of tests is completed, it is only necessary to change the core ratio to the oil and water form under the initial condition to carry out a new test. There is no need to replace the columnar artificial core 5 for each test. At the same time, the 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 can carry out different injection liquid chemical agent proportioning, oil displacement condition comparison test, and optimize the optimal chemical flooding injection system and injection-production parameters. Further, different perforation hole density, aperture, hole volume, perforation shape, and injection liquid property loss comparison test can be carried out to optimize the optimal perforation scheme. Further, the flow characteristics and seepage characteristics of the chemical flooding between the injection well and the production well can be determined, and the oil-water movement law, the remaining oil enrichment characteristics and the region of the chemical flooding reservoir can be determined.

[0048] The above description is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application still belong to the protection scope of the technical solution of the present application.

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 set in the center as an injection well, and two insertable open steel pipes are set on 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 set in the middle of the injection well and the production well; a sampling hole (6) 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, with a distance L4 of 30 cm between each row. 25 sampling holes (6) 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 outside 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 device for measuring the characteristics of chemical flooding in a full-scale wellbore according to claim 1, characterized in that: The columnar artificial rock core (5) is sleeved with a columnar artificial rock core sleeve (8).

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

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

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

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

7. The device for measuring the characteristics of chemical flooding 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 is 8 mm to 16 mm.

8. The device for measuring the characteristics of chemical flooding 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 to 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: Place a cylindrical artificial core (5), add a perforated core ring (4) outside the injection wellbore, 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 inside the device to the designed value by pressurizing and heating; S04: injecting the injection liquid from the injection well, and when the sampling hole (6) has an obvious pressure change, opening the sampling hole (6) to take a sample, and analyzing the composition and performance of the sample.

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