High-temperature-resistant and large-temperature-difference-resistant cement paste for well cementation in oil field and application of cement paste

Abstract

The invention relates to high-temperature-resistant and large-temperature-difference-resistant cement paste for well cementation in an oil field and application of the high-temperature-resistant and large-temperature-difference-resistant cement paste, in particular to the technical field of petroleum drilling, and the cement paste comprises well cementation cement, a reinforcing admixture, an AMPS / AM / AA terpolymer fluid loss agent, a defoaming agent, a retarder GWR-300L, a stabilizer and water. According to the cement paste provided by the invention, through the synergistic cooperation of the specific fluid loss agent and the retarder in a cement paste system, the obtained cement paste can resist ultrahigh temperature and large temperature difference during well cementation, so that the well cementation operation of an ultra-deep well is realized, and the effect of oil well development is ensured.

Description

Technical Field

[0001] This invention relates to the field of oil drilling technology, specifically to a high-temperature resistant cement slurry for oilfield cementing and its applications. Background Technology

[0002] Currently, deep and ultra-deep oil and gas have become particularly important alternative energy sources in China, and the number of ultra-deep wells is increasing. The quality of the wellbore directly affects the success or failure of drilling projects and the lifespan of oil and gas wells. Cementing is a key technology to ensure the quality of well projects, and cement slurry is the core technology of cementing. It is an important means to ensure the sustainable and high-quality development of oil and gas field exploration and development.

[0003] Due to the complex geological conditions, pressure systems, temperature systems, and well depth structure of ultra-deep wells, it is essential to ensure long-term sealing quality. Especially under conditions of narrow safety density windows, difficulty in single-pass cementing and continuous cement filling, and the coexistence of high and low pressures, the cementing quality pass rate is low, necessitating further improvements in cement slurry performance.

[0004] In recent years, polymer cementing admixtures resistant to large temperature differences have seen the fastest development, such as common products like LW-1, FC-03, SK-1, TD-X, TD-S, J-2B, T121, T-50A, and W99. For example, CN115304302A discloses a cementing admixture suitable for CO2-EGS and its preparation method, which relates to the field of cementing materials technology for oil and gas field development. The cementing admixture's components, by weight percentage, include 55%-65% lithium slag, 25% aerated concrete waste, 5%-10% sodium molybdate, and 5%-10% aluminum hypophosphite.

[0005] CN107902933A discloses an admixture for high-temperature degradation resistance in oil well cement and its preparation method, which solves the problem that the existing cement slurry system is not suitable for cementing geothermal wells where ultra-high temperature and ultra-large temperature difference coexist. The admixture includes: 40%-60% photovoltaic silicon, 15%-30% fumed silica, 15%-30% reburned magnesia, and 1%-2% mineral fiber.

[0006] Although many additives have been practically applied to oilfield cementing and achieved good results, these additives can only be used below 200℃, and the temperature difference between circulating temperature and static temperature is within 50℃. That is, the current cement slurry system for ultra-deep wells still has the defects of not being resistant to high temperature and large temperature difference. Based on this, it is urgent to improve cementing additives and cement stone that are resistant to large temperature difference in order to further improve their temperature resistance. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a high-temperature and large temperature difference resistant cement slurry for oilfield cementing and its application, so as to solve the defect of the current cement slurry system in terms of temperature difference resistance for ultra-deep wells.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a high-temperature resistant cement slurry with large temperature difference for oilfield cementing, the cement slurry comprising:

[0010] Cementing agent, reinforcing admixture, AMPS / AM / AA terpolymer fluid loss reducer, defoamer, GWR-300L retarder, stabilizer and water.

[0011] The cement slurry provided by this invention utilizes the synergistic effect of specific water loss reducing agents and retarders within the cement slurry system, enabling the resulting cement slurry to withstand ultra-high temperatures (≥220℃) and large temperature differences (≥80℃) during well cementing, thereby achieving cementing operations in ultra-deep wells and ensuring the development effect of oil wells.

[0012] As a preferred embodiment of the present invention, the cement slurry comprises, by weight:

[0013] 400-600 parts cementing cement, 250-350 parts reinforcing admixture, 55-81 parts AMPS / AM / AA terpolymer fluid loss reducer, 1.5-2 parts defoamer, 32-48 parts GWR-300L retarder, 0.1-0.2 parts stabilizer, and 270-400 parts water.

[0014] As a preferred embodiment of the present invention, the cementing cement includes Grade G cementing cement.

[0015] As a preferred embodiment of the present invention, the reinforcing admixture comprises quartz sand with a particle size of 200-350 mesh.

[0016] As a preferred technical solution of the present invention, the AMPS / AM / AA terpolymer water loss reducing agent includes water loss reducing agent GWF-200L.

[0017] As a preferred embodiment of the present invention, the defoamer includes defoamer GWX-1L or tributyl phosphate.

[0018] As a preferred embodiment of the present invention, the stabilizer includes one or a combination of at least two of Brunei gum, xanthan gum, or bio-gum.

[0019] In a second aspect, the present invention provides an application of the cement slurry as described in the first aspect, the application including: using the cement slurry for well cementing.

[0020] As a preferred technical solution of the present invention, the cementing operation temperature is ≥220℃.

[0021] As a preferred technical solution of the present invention, the cementing operation temperature difference is ≥80℃.

[0022] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0023] The cement slurry provided by this invention, with the help of specific water loss reducing agents and coagulants, achieves high temperature resistance and large temperature difference performance of cement slurry, which is beneficial to cementing operations in ultra-deep wells and thus ensures the development effect of oil wells. After 28 days of curing, the compressive strength is ≥42.7MPa at 220℃ and ≥39.2MPa at 350℃. Detailed Implementation

[0024] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0025] This embodiment provides a high-temperature resistant cement slurry with large temperature difference for oilfield cementing, the cement slurry comprising:

[0026] Cementing agent, reinforcing admixture, AMPS / AM / AA terpolymer fluid loss reducer, defoamer, GWR-300L retarder, stabilizer and water.

[0027] Specifically, the cement slurry comprises, by weight:

[0028] 400-600 parts cementing cement, 250-350 parts reinforcing admixture, 55-81 parts AMPS / AM / AA terpolymer fluid loss reducer, 1.5-2 parts defoamer, 32-48 parts GWR-300L retarder, 0.1-0.2 parts stabilizer, and 270-400 parts water.

[0029] In this invention, the cement cement in the cement slurry is 400-600 parts by weight, for example, 400 parts, 420 parts, 440 parts, 460 parts, 480 parts, 500 parts, 520 parts, 540 parts, 560 parts, 580 parts or 600 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0030] In this invention, the reinforcing admixture in the cement slurry is 250-350 parts by weight, for example, 250 parts, 260 parts, 270 parts, 280 parts, 290 parts, 300 parts, 310 parts, 320 parts, 330 parts, 340 parts or 350 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0031] In this invention, the AMPS / AM / AA terpolymer water loss reducing agent in the cement slurry is 55-81 parts by weight, for example, it can be 55 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts or 81 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0032] In this invention, the defoamer in the cement slurry is 1.5-2 parts by weight, for example, it can be 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0033] In this invention, the retarder GWR-300L in the cement slurry is 32-48 parts by weight, for example, it can be 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts or 48 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0034] In this invention, the stabilizer in the cement slurry is 0.1-0.2 parts by weight, for example, it can be 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts or 0.2 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0035] In this invention, the water in the cement slurry is 270-400 parts by weight, for example, 270 parts, 280 parts, 290 parts, 300 parts, 310 parts, 320 parts, 330 parts, 340 parts, 350 parts, 360 parts, 370 parts, 380 parts, 390 parts, or 400 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0036] The cementing cement includes Grade G cementing cement.

[0037] The reinforcing admixture includes quartz sand with a particle size of 200-350 mesh.

[0038] In this invention, the particle size is selected as an aggregate of particles of a single size within a limited range, or an aggregate of all particles within a certain range.

[0039] The AMPS / AM / AA terpolymer water loss reducing agent includes water loss reducing agent GWF-200L.

[0040] The defoamer includes defoamer GWX-1L or tributyl phosphate.

[0041] The stabilizer includes one or a combination of at least two of Brunei gum, xanthan gum, or bio-gum.

[0042] In this invention, the cement slurry is prepared by mixing ingredients according to their weight proportions.

[0043] Furthermore, this embodiment provides the use of the cement slurry as described above, including: using the cement slurry for well cementing.

[0044] The cementing operation temperature is ≥220℃, for example, it can be 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0045] The cementing operation temperature difference is ≥80℃, for example, it can be 80℃, 85℃, 90℃, 95℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0046] In this invention, the operating temperature difference in cementing refers to the temperature difference between the circulating temperature and the static temperature, or the temperature difference between the bottom hole temperature and the return temperature.

[0047] In this invention, the cement slurry provided can also be used for cementing wells with an operating temperature of <220℃ and / or a temperature difference of <80℃, because the aforementioned working conditions are significantly better than the working conditions targeted by this invention, i.e., the working conditions of this invention are relatively harsh.

[0048] Furthermore, to illustrate the excellent cementing effect achievable by the cement slurry provided by the present invention, the following practical example is provided for illustrative purposes:

[0049] Example 1

[0050] This embodiment provides a high-temperature resistant cement slurry with large temperature difference for oilfield cementing, comprising, by weight:

[0051] 500 parts cementing cement, 300 parts reinforcing admixture, 70 parts AMPS / AM / AA terpolymer fluid loss reducer, 1.8 parts defoamer, 40 parts GWR-300L retarder, 0.15 parts stabilizer, and 350 parts water;

[0052] The cementing cement is Grade G cementing cement;

[0053] The reinforcing admixture is quartz sand with a particle size of 200-300 mesh;

[0054] The AMPS / AM / AA terpolymer water loss reducing agent is water loss reducing agent GWF-200L;

[0055] The defoamer is defoamer GWX-1L;

[0056] The stabilizer is Brunei gum.

[0057] Example 2

[0058] This embodiment provides a high-temperature resistant cement slurry with large temperature difference for oilfield cementing, comprising, by weight:

[0059] 400 parts cementing cement, 250 parts reinforcing admixture, 55 parts AMPS / AM / AA terpolymer fluid loss reducer, 1.5 parts defoamer, 48 parts GWR-300L retarder, 0.2 parts stabilizer, and 270 parts water;

[0060] The cementing cement is Grade G cementing cement;

[0061] The reinforcing admixture is quartz sand with a particle size of 250-350;

[0062] The AMPS / AM / AA terpolymer water loss reducing agent is water loss reducing agent GWF-200L;

[0063] The defoamer is tributyl phosphate;

[0064] The stabilizer is hydroxyethyl cellulose.

[0065] Example 3

[0066] This embodiment provides a high-temperature resistant cement slurry with large temperature difference for oilfield cementing, comprising, by weight:

[0067] The mixture consists of 600 parts cementing cement, 350 parts reinforcing admixture, 81 parts AMPS / AM / AA terpolymer fluid loss reducer, 2 parts defoamer, 32 parts GWR-300L retarder, 0.1 parts stabilizer, and 400 parts water.

[0068] The cementing cement is Grade G cementing cement;

[0069] The reinforcing admixture is quartz sand with a particle size of 220-300 mesh;

[0070] The AMPS / AM / AA terpolymer water loss reducing agent is water loss reducing agent GWF-200L;

[0071] The defoamer is defoamer GWX-1L;

[0072] The stabilizer is xanthan gum.

[0073] Example 4

[0074] The only difference from Example 1 is that the water loss reducing agent GWF-200L is replaced with an equal amount of water loss reducing agent DS-1.

[0075] Example 5

[0076] The only difference from Example 1 is that the water loss reducing agent GWF-200L is replaced with an equal amount of the water loss reducing agent DRG.

[0077] Example 6

[0078] The only difference from Example 1 is that the water loss reducing agent GWF-200L is replaced with an equal amount of water loss reducing agent D181.

[0079] Example 7

[0080] The only difference from Example 1 is that the retarder GWR-300L is replaced with an equal amount of retarder HS201L.

[0081] Example 8

[0082] The only difference from Example 1 is that the retarder GWR-300L is replaced with an equal amount of citric acid as a retarder.

[0083] Example 9

[0084] The only difference from Example 1 is that the retarder GWR-300L is replaced with an equal amount of retarder DRH-2L.

[0085] The cement slurry obtained in the above examples was subjected to a thickening test according to the requirements of GB / T-10238 at a temperature of 220℃. The results are shown in Table 1 below.

[0086] Table 1

[0087]

[0088]

[0089] As shown in Table 1, the cement slurry provided by the present invention uses a specific AMPS / AM / AA terpolymer water loss reducer and a retarder GWR-300L to achieve a thickening closer to a right angle, resulting in better anti-channeling performance.

[0090] Furthermore, curing tests were conducted on the cement slurry obtained in the above embodiments. The results are shown in Tables 2 and 3 below. Table 2 shows the results of the 48-hour curing test, specifically the large temperature difference test. The first column of the data in the table represents the static curing strength, and the second column represents the curing strength under temperature difference. That is, the cement slurry was heated to 220℃ in 120 minutes, kept at a constant temperature for 20 minutes, cooled to the target temperature, and then removed for the strength curing test. The 220℃ test data represents the static curing data. Table 3 shows the results of the 28-day curing test, which represents the data after the cement stone was demolded for 48 hours and then cured for 28 days.

[0091] Table 2

[0092]

[0093]

[0094] Table 3

[0095]

[0096] As shown in Tables 2 and 3, the cement slurry system provided by the present invention, by using specific water loss reducing agents and retarders, enables the cement slurry to withstand ultra-high temperatures (≥220℃) and large temperature differences (≥80℃) when cementing wells, thereby enabling cementing operations in ultra-deep wells and ensuring the development effect of oil wells.

[0097] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0098] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0099] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-temperature, large-temperature-difference resistant cement slurry for oilfield cementing, characterized in that, The cement slurry includes: Cementing agent, reinforcing admixture, AMPS / AM / AA terpolymer fluid loss reducer, defoamer, GWR-300L retarder, stabilizer and water.

2. The cement grout as described in claim 1, characterized in that, The cement slurry comprises, by weight: 400-600 parts cementing cement, 250-350 parts reinforcing admixture, 55-81 parts AMPS / AM / AA terpolymer fluid loss reducer, 1.5-2 parts defoamer, 32-48 parts GWR-300L retarder, 0.1-0.2 parts stabilizer, and 270-400 parts water.

3. The cement grout as described in claim 1, characterized in that, The cementing cement includes Grade G cementing cement.

4. The cement grout as described in claim 1, characterized in that, The reinforcing admixture includes quartz sand with a particle size of 200-350 mesh.

5. The cement grout as described in claim 1, characterized in that, The AMPS / AM / AA terpolymer water loss reducing agent includes water loss reducing agent GWF-200L.

6. The cement grout as described in claim 1, characterized in that, The defoamer includes defoamer GWX-1L or tributyl phosphate.

7. The cement grout as described in claim 1, characterized in that, The stabilizer includes one or a combination of at least two of Brunei gum, xanthan gum, or bio-gum.

8. A use of the cement grout as described in claim 1, characterized in that, The applications include: using the cement slurry for well cementing.

9. The use as described in claim 8, characterized in that, The cementing operation temperature is ≥220℃.

10. The use as described in claim 8, characterized in that, The cementing operation temperature difference is ≥80℃.

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