An online profile adjustment device and method

Abstract

This disclosure relates to an online profile control device and method. The outlet pipeline of the crosslinking agent tank (17) of the device is connected to the pipeline between the mother liquor storage tank (13) and the injection pump (14). Since the device only mixes the stabilizer and the polymer at the curing end, that is, the crosslinking agent does not participate in the curing, but is added before the injection pump, the viscosity of the system can be kept stable. It is precisely because the profile control system after adding the crosslinking agent before the injection station pump has good viscosity stability that the gelation process of the profile control system can be ensured to occur during the injection into the underground profile control layer and migration into the deep formation. This is more conducive to the system advancing into the deep formation, improving the adjustment effect of the deep oil layer, and effectively solving a series of problems caused by the unstable viscosity of the system after mixing due to the direct curing of three agents.

Description

Technical Field

[0001] This disclosure relates to the field of tertiary oil recovery technology, and in particular to an online profile control device and method. Background Technology

[0002] Profile control technology is an important technique for adjusting the horizontal and / or vertical differences of oil reservoirs during oilfield development, which can more effectively improve the efficiency of displacement agents. Existing profile control processes mainly consist of preparation, injection, and supporting facilities. Figure 1 The preparation section mainly includes a dispersion tank 1, a maturation tank 2, a profile control agent storage tank 3, a crosslinking agent storage tank 4, a matching water pressure reducing device and a water buffer tank; the injection section includes a feeding device and a polymer injection pump 5; the supporting parts include a material storage room, a duty room, etc.

[0003] The specific profile control process involves reducing the pressure of the high-pressure water from the injection station, injecting the polymer and stabilizer dry powder into the dispersion tank 1, and simultaneously adding the crosslinking agent from the crosslinking agent storage tank 4 into the dispersion tank 1 according to the plan requirements before it enters the maturation tank 2 for maturation. The matured profile control agent is then injected into the profile control agent storage tank 3, and then pumped to the polymer injection pump 5 for pressurization via the feeding pump, and injected into the injection well 6 through the injection station valve group.

[0004] However, the profile control agent obtained by mixing and maturing polymers, stabilizers, and crosslinking agents exhibits unstable system viscosity. If not properly managed, it can easily lead to premature gelation, clogging of equipment and the near-wellbore area of ​​the oil layer. Summary of the Invention

[0005] In view of this, this disclosure provides an online profile control device and method to solve the problem of unstable system viscosity of the profile control agent prepared in the current profile control process.

[0006] To achieve the above-mentioned objectives, in a first aspect, the online profile adjustment device disclosed herein includes:

[0007] Polymer dispersion tank, maturation tank, mother liquor storage tank, injection pump, stabilizer dosing device and crosslinking agent tank;

[0008] The outlet of the stabilizer dosing device is connected to the polymer dispersion tank;

[0009] The outlet pipeline of the crosslinking agent tank is connected to the pipeline between the mother liquor storage tank and the injection pump.

[0010] In this disclosure and possible embodiments, the stabilizer dosing device includes a storage tank, the outlet of which is connected to a feeding control mechanism and a feeding funnel, and the feeding funnel is connected to a polymer dispersion tank.

[0011] In this disclosure and possible embodiments, the stabilizer dosing device adopts a skid-mounted structure.

[0012] In this disclosure and possible embodiments, the feeding control mechanism is a screw feeder.

[0013] In this disclosure and possible embodiments, the outlet of the crosslinking agent tank is connected to a delivery pump, and the outlet of the delivery pump is connected to a pipeline between the mother liquor storage tank and the injection pump.

[0014] In this disclosure and possible embodiments, the delivery pump 8 is an automatic dosing metering pump.

[0015] In this disclosure and possible embodiments, the crosslinking agent tank and the delivery pump 8 are configured as skid-mounted structures.

[0016] Secondly, the online profile adjustment method described in this disclosure includes:

[0017] The online profile adjustment is performed using the online profile adjustment device described in any one of the first aspects.

[0018] In this disclosure and possible embodiments, the polymer is diluted with clean water or wastewater according to a set ratio and added to a polymer dispersion tank. A stabilizer is added to the polymer dispersion tank through a stabilizer dosing device. The mixed dispersion of the polymer and the stabilizer is input into a maturation tank and matured for a set time before being input into a mother liquor storage tank. When profile adjustment is required, a crosslinking agent is delivered to the injection pump in front of the injection pump according to a set crosslinking ratio, and the material in the mother liquor storage tank and the crosslinking agent are simultaneously injected into the injection well through the injection pump.

[0019] In this disclosure and possible embodiments, the polymer is polyacrylamide, the stabilizer is industrial thiourea, and the crosslinking agent is a chromium ion crosslinking agent.

[0020] The beneficial effects of this invention are:

[0021] The online profile control device and method disclosed herein address the issue that existing profile control processes involve mixing, curing, and injecting polymers, stabilizers, and crosslinking agents. This method is highly susceptible to factors such as the quality of the additives and the curing time, leading to unstable initial viscosity and premature gelation, potentially causing equipment blockages and production accidents in the near-wellbore zone. In contrast, the online profile control device and method of this disclosure only mixes the stabilizer and polymer at the curing stage; the crosslinking agent is added before the injection pump, thus maintaining stable system viscosity. Because the profile control system, after mixing with the crosslinking agent before the injection pump, exhibits better viscosity stability, the gelation process occurs during the injection into the underground profile control zone and as the system migrates deeper into the formation. This facilitates deeper penetration and improves the adjustment effect in deeper oil layers, effectively solving a series of problems caused by unstable viscosity after mixing the three agents during direct curing. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0023] Figure 1 This is a diagram of the existing profile control process equipment;

[0024] Figure 2 This is a diagram of the existing polymer flooding and injection process equipment;

[0025] Figure 3 This is a diagram of the online profile adjustment device according to an embodiment of this disclosure;

[0026] Figure 4 This is a schematic diagram of the stabilizer dosing device according to an embodiment of the present disclosure;

[0027] Figure 5 This is a schematic diagram of the crosslinking agent dosing device according to an embodiment of this disclosure. Detailed Implementation

[0028] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote components that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0029] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0030] The oilfield polymer flooding injection process also includes a polymer dispersion tank 11, a maturation tank 12, a mother liquor storage tank 13, and an injection pump 14. Figure 2 ).and Figure 1 The profile adjustment process devices shown are highly similar, and the process meets the basis for optimization and improvement. Therefore, the online profile adjustment device disclosed herein can be configured based on the existing injection facilities and online profile adjustment can be carried out.

[0031] Figure 3 This is a diagram of an online profile adjustment process apparatus based on existing dispensing facilities, as described in this embodiment; Figure 3 As shown, the online profile control process device relying on existing injection facilities includes a polymer dispersion tank 11, a maturation tank 12, a mother liquor storage tank 13, an injection pump 14, a stabilizer dosing device 16, and a crosslinking agent tank 17.

[0032] In one specific embodiment, by Figure 4As shown, the stabilizer dosing device 16 includes a storage tank 21. The lower outlet of the storage tank 21 is connected to a feeding control mechanism 22, and the feeding outlet is connected to a feeding funnel 23. The feeding funnel is connected to the polymer dispersion tank 11. That is, the stabilizer dosing device 16 is configured as a skid-mounted automatic feeding device to realize the automatic dosing of stabilizer. Preferably, the feeding control mechanism 22 is a screw feeder, which is a screw feeding mechanism. More preferably, the stabilizer dosing device 16 adopts a skid-mounted structure, that is, the storage tank 21, the feeding control mechanism 22, and the feeding funnel 23 are combined on the skid plate 24, which facilitates the overall relocation.

[0033] In one specific embodiment, by Figure 5 As shown, a delivery pump 18 is connected to the outlet of the crosslinking agent tank 17. The outlet of the delivery pump 18 is connected to the pipeline between the mother liquor storage tank 13 and the injection pump 14. That is, the crosslinking agent in the crosslinking agent tank 17 is mixed with the matured polymer and stabilizer in the mother liquor storage tank 13 by the delivery pump 18 before entering the injection pump 14, and then injected into the injection well 15 by the injection pump 14. Of course, the delivery pump 18 is preferably an automatic dosing metering pump, such as a drip metering pump, and it is preferable to set the crosslinking agent tank 17 and the delivery pump 18 as skid-mounted, that is, to combine the crosslinking agent tank 17 and the delivery pump 18 on a skid plate to realize automatic dosing of the crosslinking agent, which also facilitates overall relocation.

[0034] The following is adopted in this disclosure Figure 3 The method for online profile adjustment using the aforementioned online profile adjustment device is as follows:

[0035] 1. Dilute the polymer with clean water or wastewater according to the set ratio and add it to the polymer dispersion tank 11. Add the stabilizer to the polymer dispersion tank 11 through the stabilizer dosing device 16.

[0036] 2. The mixed dispersion of the polymer and the stabilizer is fed into the maturation tank 12 and matured for a set time, and then fed into the mother liquor storage tank 13;

[0037] 3. When profile adjustment is required, crosslinking agent is delivered to injection pump 14 in advance according to the set crosslinking ratio, and the material in mother liquor storage tank 13 and crosslinking agent are simultaneously injected into injection well 15 through injection pump 14.

[0038] In one specific embodiment, the polymer is polyacrylamide, the stabilizer is industrial thiourea, and the crosslinking agent is a chromium ion crosslinking agent.

[0039] Example 1

[0040] In this embodiment 1, the preparation process of the online profile control system of this application is simulated indoors. Specifically, in the polymer dispersion tank 11, the polymer (polyacrylamide) is dispersed at a concentration of 5000 mg / L and the stabilizer (industrial thiourea) at a concentration of 800 mg / L. Then, the dispersed and mixed material is transported to the maturation tank 12 for maturation. Unlike the existing profile control process, only the polyacrylamide and the stabilizer industrial thiourea are mixed and matured at this time, without the addition of chromium ion crosslinking agent. After maturation time of 3 hours, the mixture is pumped into the mother liquor storage tank 13. Then, chromium ion crosslinking agent is added in front of the injection pump 14 at a polymerization ratio of 18:1. After mixing, the mixture is injected into the injection well 15.

[0041] Furthermore, this embodiment 1 compares the technical effects of the present application with those of existing profile adjustment processes. Specifically, in... Figure 1 In the profile control process device shown, polyacrylamide and industrial thiourea are dispersed and mixed in dispersion tank 1 according to the same ratio of polymer (polyacrylamide) concentration of 5000 mg / L and stabilizer (industrial thiourea) concentration of 800 mg / L and then fed into curing tank 2. During the transportation process, chromium ion crosslinking agent is fed into curing tank 2 together at a ratio of 18:1. After the polyacrylamide, industrial thiourea and chromium ion crosslinking agent are cured together in curing tank 2 for 3 hours, they are pumped into profile control fluid storage tank 3 and finally injected into injection well 6 by injection pump 5.

[0042] The viscosity of the profiled systems obtained by the two profiled modification methods described above was tested. Specifically, the viscosity of the profiled systems was tested according to the Polymer Solution Sampling and Testing Procedure (Q / SY DQ0925-2012). The results are shown in Table 1.

[0043] Table 1 Comparison of viscosity between the two methods

[0044]

[0045]

[0046] Note: The chromium ion crosslinking agent was purchased from Daqing High-tech Zone Hualongxiang Chemical Co., Ltd.

[0047] The comparative data in Table 1 shows that the viscosity of the two batches of the profile control system using the proposed method in Example 1 did not change significantly at the initial, 3-day, and 5-day stages, indicating good stability of the viscosity in the indoor simulation system. In contrast, the three batches of the profile control system using the existing process showed that the first batch failed to gel, the second batch was normal, but the initial viscosity (mPa·s) of the third batch reached over 8000. Therefore, gelation may occur in the curing tank during the preparation process, potentially leading to premature gelation and blockage of the equipment and the near-wellbore area of ​​the oil layer. The above comparison demonstrates that the proposed profile control method can significantly avoid the problem of premature gelation caused by unstable initial viscosity in the profile control system.

[0048] Example 2

[0049] The polymer (polyacrylamide) was prepared with clean water at a concentration of 5000 mg / L, then diluted with wastewater to 2500 mg / L, and the stabilizer (industrial thiourea) was dispersed at a concentration of 1600 mg / L. The dispersed and mixed material was then fed into maturation tank 12 for maturation. After maturation for 3 hours, the mixture was pumped into mother liquor storage tank 13. Chromium ion crosslinking agent was then added before injection pump 14 at a crosslinking ratio of 18:1, and the mixture was injected into injection well 15. The viscosity of the profile control system in Example 2 was tested, and the results are shown in Table 2.

[0050] Table 2 Stability of the Profile Adjustment System

[0051]

[0052] As can be seen from Table 2, the profile adjustment system of this Example 2 can ensure the stability of the initial system viscosity, avoid premature gelation, ensure normal gelation, and ensure a relatively stable time period after gelation.

[0053] The test results of the above embodiments show that the online profile control device and method disclosed herein, which only mixes stabilizer and polymer at the curing end, can ensure that the initial viscosity of the profile control system remains stable (Table 1). The profile control system after adding crosslinking agent before the injection station pump has good gelling performance and stability (Table 2). The gelling process of the profile control system occurs during the migration to the deeper formation after injection into the underground profile control section, which is more conducive to the system advancing to the deeper formation and improving the adjustment effect of deep oil layers. This effectively avoids a series of problems caused by the unstable initial viscosity of the system and premature gelling due to the current method of directly curing and mixing three agents.

[0054] It is understood that the various method embodiments mentioned above in this disclosure can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this disclosure will not elaborate further.

[0055] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An online profile adjustment device, characterized in that, include: Polymer dispersion tank (11), maturation tank (12), mother liquor storage tank (13), injection pump (14), stabilizer dosing device (16) and crosslinking agent tank (17). The outlet of the stabilizer dosing device (16) is connected to the polymer dispersion tank (11); The outlet pipeline of the crosslinking agent tank (17) is connected to the pipeline between the mother liquor storage tank (13) and the injection pump (14).

2. The online profile adjustment device according to claim 1, characterized in that: The stabilizer dosing device (16) includes a storage tank (21), the outlet of which is connected to a feeding control mechanism (22) and a feeding funnel (23), and the feeding funnel (23) is connected to a polymer dispersion tank (11).

3. The online profile adjustment device according to claim 2, characterized in that: The stabilizer dosing device (16) adopts a skid-mounted structure.

4. The online profile adjustment device according to claim 2 or 3, characterized in that: The feeding control mechanism (22) is a screw feeder.

5. The online profile adjustment device according to claim 4, characterized in that: The outlet of the crosslinking agent tank (17) is connected to the delivery pump (18), and the outlet of the delivery pump (18) is connected to the pipeline between the mother liquor storage tank (13) and the injection pump (14).

6. The online profile adjustment device according to claim 5, characterized in that: The delivery pump (18) is an automatic dosing metering pump.

7. The online profile adjustment device according to claim 5 or 6, characterized in that: The crosslinking agent tank (17) and the delivery pump (18) are configured as skid-mounted structures.

8. An online profile adjustment method, characterized in that, include: The online profile adjustment is performed using the online profile adjustment device according to any one of claims 1-7.

9. The online profile adjustment method according to claim 8, characterized in that: According to the set ratio, the polymer is diluted with clean water or sewage and added to the polymer dispersion tank (11). The stabilizer is added to the polymer dispersion tank (11) through the stabilizer dosing device (16). The mixed dispersion of the polymer and the stabilizer is input into the maturation tank (12) and matured for a set time, and then input into the mother liquor storage tank (13). When profile adjustment is required, crosslinking agent is delivered to the injection pump (14) in front of the injection pump (14) according to the set crosslinking ratio, and the material in the mother liquor storage tank (13) and the crosslinking agent are simultaneously injected into the injection well (15) through the injection pump (14).

10. The online profile adjustment method according to claim 9, characterized in that: The polymer is polyacrylamide, the stabilizer is industrial thiourea, and the crosslinking agent is a chromium ion crosslinking agent.

Images