Method for testing initial setting time of polymer cement paste plugging agent

Abstract

The invention belongs to the technical field of oil-water well plugging, and particularly relates to a method for testing the initial setting time of a polymer cement paste plugging agent. The testing method comprises the following steps: measuring the sample viscosity of the polymer cement paste plugging agent by using a viscometer, and when the sample viscosity reaches 9000-10000 mPa.s, the used time is the initial setting time of the polymer cement paste plugging agent. According to the method for testing the initial setting time of the polymer cement paste plugging agent, a viscosity-time curve is used for testing the initial setting time of the polymer cement paste plugging agent, and the viscosity value range during initial setting is determined. The test method is safe and reliable, the measured initial setting time data is real and accurate, and the construction safety and the construction effect of the oil field plugging site are powerfully guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of oil and water well plugging technology, specifically relating to a method for testing the initial setting time of polymer cement slurry plugging agent. Background Technology

[0002] Oil and water well plugging measures are crucial supporting measures for improving oil and water well production and ensuring safe oilfield production during development and construction. Cement-based materials are the most widely used inorganic cementitious materials in oilfield plugging measures, possessing advantages such as high strength, low permeability, readily available raw materials, and simple production. However, they also suffer from drawbacks such as high brittleness of the solidified body, poor corrosion resistance, and insufficient durability, necessitating modification. Research indicates that resin polymers, due to their molecular chain structure and the self-rotation of chain segments or units, exhibit good elasticity and plasticity. Adding resin polymers to cement-based materials in a specific proportion to form polymer cement slurry plugging agents can solve the problems of high brittleness, low impermeability, and insufficient durability of hardened cement stone. Currently, commonly used resin polymers in oilfields mainly include latex polymer resins, unsaturated polyester resins, phenolic resins, urea-formaldehyde resins, and epoxy resins.

[0003] Because the window period for oilfield plugging operations is relatively long, in order to ensure construction safety, the polymer cement slurry plugging agent needs sufficient liquid pumping time to ensure that the plugging agent can replace the target location during construction. Therefore, it is necessary to test the initial setting time of the polymer cement slurry plugging agent.

[0004] The primary method for testing the initial setting time of oilfield cement slurry plugging agents is the thickening time evaluation method in GB / T 19139—2012 "Test Methods for Cement in Oil Wells". This involves preparing the cement slurry plugging agent, loading it into a thickener equipped with a paddle, setting the experimental temperature and pressure, and determining the initial setting time when the cement slurry consistency reaches 100 BC. This evaluation method can dynamically reflect the consistency change of the cement slurry plugging agent under simulated high temperature and high pressure conditions in oil reservoirs, and accurately determine the initial setting time of the cement slurry. However, it is not suitable for testing the initial setting time of polymer cement slurry plugging agents.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a test method for the initial setting time of polymer cement slurry plugging agent; this test method is safe and reliable, and the measured initial setting time data is true and accurate, which effectively ensures the safety and construction effect of oilfield plugging site construction.

[0007] To overcome the shortcomings of the prior art, the present invention provides the following technical solution:

[0008] A method for testing the initial setting time of a polymer cementitious grout sealant includes the following steps:

[0009] The viscosity of the polymer cement slurry plugging agent sample was measured using a viscometer. The time taken for the sample viscosity to reach 9000-10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent.

[0010] Furthermore, the viscometer is a rotational viscometer.

[0011] Furthermore, it includes the following steps:

[0012] S1. Pour the polymer cement slurry plugging agent sample into the sample cell of the rotation viscometer, and adjust the rotation speed and measurement temperature.

[0013] S2. Start the viscometer at regular intervals to measure the viscosity of the sample. The time taken when the viscosity reaches 9000-10000 mPa·s is the initial setting time of the polymer cement slurry sealant.

[0014] Further, in step S1, the rotation speed is adjusted to 3-30 revolutions per minute; and / or, the measured temperature is the actual temperature inside the oil / water well.

[0015] Furthermore, in step S2, the viscometer is activated every 10 to 30 minutes.

[0016] Furthermore, in the polymer cement slurry sealant, the volume ratio of cement slurry to resin polymer is (1-3):1.

[0017] Furthermore, the density of the cement slurry is 1.70-1.85 g / cm³. 3 .

[0018] Furthermore, the initial viscosity of the resin polymer is ≤2000 mPa·s.

[0019] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0020] The method for testing the initial setting time of polymer cement slurry plugging agent of the present invention uses a viscosity-time curve to test the initial setting time of the polymer cement slurry plugging agent and determines the viscosity range at initial setting. This testing method is safe and reliable, and the measured initial setting time data is true and accurate, effectively ensuring the safety and construction effect of oilfield plugging site construction. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0022] Figure 1 This is a viscosity-time curve of the polymer cement slurry plugging agent of the present invention;

[0023] Figure 2 This is a viscosity-temperature curve of the resin material;

[0024] Figure 3 This is a consistency-time curve for cement. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0026] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0027] This invention provides a method for testing the initial setting time of a polymer cement slurry plugging agent, comprising the following steps: measuring the viscosity of a sample of the polymer cement slurry plugging agent using a viscometer; the time taken for the sample viscosity to reach 9000-10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent.

[0028] The inventors discovered through research that the curing reaction of resin polymers differs from the hydration reaction of cement. After the resin curing reaction begins, the viscosity of the system gradually increases, and the flow resistance gradually rises, exhibiting a slow "climbing" characteristic in viscosity (see appendix). Figure 1 The consistency of cement exhibits a "right-angle" characteristic (see appendix). Figure 2This means that the consistency of the cement slurry increases very little or even remains constant over a long period of time, but rapidly increases until it loses its fluidity near the thickening time. Furthermore, polymer cement slurry plugging agents, formed by the compounding of resin polymers and cement slurry, have a higher viscosity than cement slurry plugging agents. Therefore, at the same fluidity, the thickener's blades experience greater flow resistance in the polymer cement slurry, exhibiting a "pole-climbing" phenomenon. The measured consistency is also higher compared to cement slurry plugging agents. Cement slurry loses its fluidity at 100 BC, while polymer cement slurry plugging agents maintain a fluidity of 21 cm at 100 BC, still exhibiting good fluidity (see Table 1). Therefore, using the "consistency-time curve" cannot accurately determine the initial setting time of polymer cement slurry plugging agents.

[0029] In this invention, when measuring the viscosity of polymer cement slurry plugging agent samples using a viscometer, it is first necessary to determine the viscosity range of the polymer cement slurry at its initial setting. Samples of the polymer cement slurry plugging agent are taken, and parallel samples are tested for consistency, viscosity, and flowability at different times. The consistency test is conducted using a thickener, the viscosity test using a viscometer, and the flowability test is performed according to the net flowability test method for cement slurry in GB / T 8077-2023. The experimental data are shown in Table 1.

[0030] Table 1

[0031] Consistency / BC 6 10 20 40 60 98 / / Viscosity / mPa.s 102 211 533 859 1585 3257 9864 16520 Flowability / cm 30 28 27 25 22 21 18 14

[0032] Table 1 shows that conventional cement slurry loses its fluidity when its consistency reaches 100 BC, while the polymer cement slurry plugging agent, with a consistency close to 100 BC, exhibits a fluidity of 21 cm and a viscosity of 3257, still demonstrating good fluidity. This indicates that the "consistency-time curve" cannot accurately determine the initial setting time of the polymer cement slurry plugging agent. When the viscosity of the polymer cement slurry plugging agent reaches approximately 10000 mPa·s, the fluidity is 18 cm, indicating good fluidity. After this point, the viscosity rises rapidly, and the fluidity decreases significantly, making further testing less meaningful and increasing the difficulty of cleaning the experimental equipment due to the plugging agent's hardening. Therefore, the viscosity range of the polymer cement slurry at initial setting was determined to be 9000–10000 mPa·s. A "viscosity-time curve" was plotted based on the polymer cement slurry viscosity range and testing time (see attached figure). Figure 1 (As shown).

[0033] It is understood that in the test method of the present invention, the viscometer includes, but is not limited to, a rotational viscometer, as long as it can ensure that the maximum measurement range of viscosity can reach 10000 mPa·s or higher. When using a rotational viscometer, the test method includes the following steps:

[0034] S1. Pour the polymer cement slurry plugging agent sample into the sample cell of the rotation viscometer, and adjust the rotation speed and measurement temperature.

[0035] S2. Start the viscometer at regular intervals to measure the viscosity of the sample. The time taken when the viscosity reaches 9000-10000 mPa·s is the initial setting time of the polymer cement slurry sealant.

[0036] In the above testing method, the method of measuring viscosity using a rotational viscometer is a conventional operation in the art and will not be described in detail here. As a preferred embodiment, the rotational speed of the rotational viscometer is adjusted to 3-30 rpm; and / or, the measured temperature is the actual temperature inside the oil / water well. Optionally, the measured temperature is the actual temperature inside the oil / water well.

[0037] In the above testing method, as a preferred implementation, the viscometer is started every 10-30 minutes. Initially, before the plugging agent undergoes a gelation reaction, the viscosity of the system does not change significantly, so measurements can be taken every 30 minutes. Later, as the plugging agent begins to gel, the viscosity of the system increases rapidly, requiring measurements to be taken every 10 minutes to ensure testing accuracy.

[0038] In the above testing method, as a preferred embodiment, the volume ratio of cement slurry to resin polymer in the polymer cement slurry plugging agent is (1-3):1. The volume ratio of cement slurry to resin polymer in this invention is preferably controlled within this range. If it is not within this volume ratio, such as a volume ratio less than 1:1 (i.e., the amount of resin polymer added is too large), the initial viscosity of the prepared polymer cement slurry plugging agent will be too high, and the rotor will easily exhibit rod climbing phenomenon in the viscometer, causing the viscosity to increase rapidly and affecting the testing accuracy. If the volume ratio is greater than 3:1 (i.e., the amount of resin polymer added is too low), firstly, the modification effect on the cement stone is small, and secondly, the testing time is too long, resulting in decreased experimental accuracy.

[0039] In the above testing method, as a preferred embodiment, the density of the cement slurry is 1.70-1.85 g / cm³. 3 .

[0040] In the above testing method, as a preferred embodiment, the initial viscosity of the resin polymer is ≤2000 mPa·s. The density of the cement slurry and the initial viscosity of the resin polymer are preferably controlled within the range of this invention. If the density of the cement slurry and the initial viscosity of the resin polymer are too high, the initial viscosity of the prepared polymer cement slurry blocker is easily too high, and the rotor is prone to rod climbing in the viscometer, affecting the testing accuracy.

[0041] The present invention will now be described in detail with reference to embodiments thereof. These examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0042] In the embodiments of the present invention, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0043] Example 1

[0044] I. Preparation of polymer cement grout plugging agent samples:

[0045] ① Prepare cement slurry with a density of 1.82 g / cm³. 3 ;

[0046] ② The resin polymer was prepared by mixing phenolic resin and its matching curing agent at a ratio of resin:curing agent = 100:15; the initial viscosity of the resin polymer was 1050 mPa·s.

[0047] ③ The prepared cement slurry and resin polymer are thoroughly mixed at a volume ratio of 2:1 to form a polymer cement slurry plugging agent sample;

[0048] 2. Load the prepared polymer cement slurry plugging agent sample into a rotational viscometer, set the rotational speed to 3-30 rpm; the experimental temperature is 50℃.

[0049] 3. Start the viscometer every 10-30 minutes to test the viscosity of the plugging agent. The time taken for the viscosity of the plugging agent to approach 10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent. The experimental data are shown in Table 2:

[0050] Table 2

[0051]

[0052] Experimental results: As can be seen from Table 2, the time required for the sealant viscosity to reach 9678 mPa·s was 210 min, that is, the initial setting time of the polymer cement slurry sealant at 50℃ was 210 min.

[0053] Example 2

[0054] I. Preparation of polymer cement grout plugging agent samples:

[0055] ① Prepare cement slurry with a density of 1.75 g / cm³.3 ;

[0056] ② The resin polymer was prepared by mixing epoxy resin and its matching curing agent at a ratio of resin:curing agent = 100:30; the initial viscosity of the resin polymer was 1725 mPa·s.

[0057] ③ The prepared cement slurry and resin polymer are thoroughly mixed at a volume ratio of 1:1 to form a polymer cement slurry plugging agent sample;

[0058] 2. Load the prepared polymer cement slurry plugging agent sample into a rotational viscometer, set the rotational speed to 3-30 rpm; the experimental temperature is 90℃.

[0059] 3. Start the viscometer every 10-30 minutes to test the viscosity of the plugging agent. The time taken for the viscosity of the plugging agent to approach 10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent. The experimental data are shown in Table 3:

[0060] Table 3

[0061]

[0062] Experimental results: As can be seen from Table 3, the time required for the sealant viscosity to reach 9933 mPa·s was 180 min, that is, the initial setting time of the polymer cement slurry sealant at 90℃ was 180 min.

[0063] Example 3

[0064] I. Preparation of polymer cement grout plugging agent samples:

[0065] ① Prepare cement slurry with a density of 1.85 g / cm³. 3 ;

[0066] ② The resin polymer was prepared by mixing unsaturated polyester resin and its matching curing agent at a ratio of resin:curing agent = 100:10; the initial viscosity of the resin polymer was 621 mPa·s.

[0067] ③ The prepared cement slurry and resin polymer are thoroughly mixed at a volume ratio of 3:1 to form a polymer cement slurry plugging agent sample;

[0068] 2. Load the prepared polymer cement slurry plugging agent sample into a rotational viscometer, set the rotational speed to 3-30 rpm; the experimental temperature is 70℃.

[0069] 3. Start the viscometer every 10-30 minutes to test the viscosity of the plugging agent. The time taken for the viscosity of the plugging agent to approach 10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent. The experimental data are shown in Table 4:

[0070] Table 4

[0071]

[0072] Experimental results: As can be seen from Table 4, the time required for the sealant viscosity to reach 9866 mPa·s was 240 min, which means that the initial setting time of the polymer cement slurry sealant at 70℃ was 240 min.

[0073] The foregoing has described and evaluated some embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, still fall within the protection scope of the present invention.

Claims

1. A method for testing the initial setting time of a polymer cementitious grout sealant, characterized in that, Includes the following steps: The viscosity of the polymer cement slurry plugging agent sample was measured using a viscometer. The time taken for the sample viscosity to reach 9000-10000 mPa·s is the initial setting time of the polymer cement slurry plugging agent.

2. The test method according to claim 1, characterized in that, The viscometer is a rotational viscometer.

3. The test method according to claim 2, characterized in that, Includes the following steps: S1. Pour the polymer cement slurry plugging agent sample into the sample cell of the rotation viscometer, and adjust the rotation speed and measurement temperature. S2. Start the viscometer at regular intervals to measure the viscosity of the sample. The time taken when the viscosity reaches 9000-10000 mPa·s is the initial setting time of the polymer cement slurry sealant.

4. The test method according to claim 3, characterized in that, In step S1, the rotation speed is adjusted to 3-30 revolutions per minute; and / or, the measured temperature is the actual temperature inside the oil-water well.

5. The test method according to claim 3, characterized in that, In step S2, the viscometer is started every 10 to 30 minutes.

6. The test method according to any one of claims 3-5, characterized in that, In the polymer cement slurry sealant, the volume ratio of cement slurry to resin polymer is (1-3):

1.

7. The test method according to claim 6, characterized in that, The density of the cement slurry is 1.70-1.85 g / cm³. 3 .

8. The test method according to claim 6, characterized in that, The initial viscosity of the resin polymer is ≤2000 mPa·s.

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