Low-expansibility high-pressure-bearing expansion casing and preparation and application thereof

Abstract

The invention relates to the technical field of expansion pipes, in particular to a low-expansibility high-pressure-bearing expansion sleeve and preparation and application thereof. The high-pressure-bearing expansion sleeve comprises the following chemical elements in percentage by mass: 0.15%-0.3% of C, 0.2%-0.5% of Si, 1%-1.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.02% of S, 0.1%-1% of Cr, 0.2%-0.5% of Mo, 0.5%-2% of Ni, 0.05%-0.1% of V, 0.01%-0.05% of Nb and the balance of Fe. According to the invention, the contradiction between the post-expansion strength and the expandability of the existing expansion casing material is solved, so that the expansion casing material has both the post-expansion strength and the expandability.

Description

Technical Field

[0001] This application relates to the technical field of expansion tubes, specifically to a high-pressure expansion sleeve with low expansion force and its preparation and application. Background Technology

[0002] As oil extraction progresses into the middle and later stages of oilfield development, well damage frequently occurs during production. Expandable tubing technology has played a role in addressing these challenges. Expandable tubing utilizes the plasticity and toughness of expandable casing. After being lowered into the well, it expands radially using mechanical or hydraulic methods. Serving within the wellbore of oil and gas wells, expandable tubing offers a larger inner diameter after the expansion tubing is installed downhole, providing better wellbore conditions for downhole operations.

[0003] In the early stages of its application in the petroleum industry, expandable casing technology was primarily used to repair damaged casing and restore the integrity of oil and gas wellbores to facilitate continued production operations. The strength requirements for expandable casing were generally not high, only needing to meet the wellbore pressure requirements for subsequent oil and gas production. However, with the advancement of oil and gas resource exploration and development in my country, compared to casing-damaged well repair, the expansion of deep and ultra-deep well structures and the reconstruction of low-production wellbores have placed higher demands on the pressure-bearing capacity and expansion safety of expandable casing. The strength and expandability of conventional expandable casing can no longer meet these application requirements. The significant decrease in the crush strength of expanded casing under low expansion force is the most significant factor restricting the development of expandable casing technology. Therefore, developing high-pressure-bearing expandable casing with low expansion force is of great application significance. Summary of the Invention

[0004] The purpose of this invention is to resolve the contradiction between expandability and pressure-bearing capacity after expansion in current expansion sleeves, enabling expansion sleeves to reduce expansion pressure while maintaining good strength performance. The specific technical solution adopted in this application is as follows:

[0005] In a first aspect, this application provides a high-pressure expansion sleeve with low expansion force, comprising, by mass percentage, the following chemical elements: C: 0.15%–0.3%, Si: 0.2%–0.5%, Mn: 1%–1.5%, P ≤ 0.02%, S ≤ 0.02%, Cr: 0.1%–1%, Mo: 0.2%–0.5%, Ni: 0.5%–2%, V: 0.05%–0.1%, Nb: 0.01%–0.05%, and the balance Fe.

[0006] In one specific embodiment, optionally, the expansion sleeve comprises, by mass percentage, the following chemical elements: C: 0.2%–0.22%, Si: 0.2%–0.25%, Mn: 1%–1.2%, P: 0.008%–0.01%, S: 0.006%–0.009%, Cr: 0.2%–0.3%, Mo: 0.2%–0.3%, Ni: 0.5%–0.6%, V: 0.055%–0.06%, Nb: 0.01%–0.02%, and the balance Fe.

[0007] In one specific embodiment, optionally, the expansion sleeve comprises, by mass percentage, the following chemical elements: C: 0.15%–0.18%, Si: 0.3%–0.4%, Mn: 1.4%–1.5%, P: 0.01%–0.02%, S: 0.01%–0.02%, Cr: 0.1%–0.15%, Mo: 0.4%–0.5%, Ni: 1%–1.5%, V: 0.08%–0.1%, Nb: 0.04%–0.05%, and the balance Fe.

[0008] In one specific embodiment, optionally, the expansion sleeve comprises, by mass percentage, the following chemical elements: C: 0.25%–0.3%, Si: 0.4%–0.5%, Mn: 1.3%–1.5%, P: 0.005%–0.01%, S: 0.005%–0.01%, Cr: 0.5%–1%, Mo: 0.2%–0.4%, Ni: 1.6%–2%, V: 0.05%–0.07%, Nb: 0.02%–0.03%, and the balance Fe.

[0009] In one specific embodiment, optionally, the expansion pressure of the expansion sleeve is 7 to 14 MPa.

[0010] Secondly, this application also relates to a method for preparing the above-mentioned low-expansion-force, high-pressure-bearing expansion sleeve, comprising:

[0011] Smelting: Chemical elements are added to a smelting furnace according to a set ratio to smelt steel and obtain uniform molten steel;

[0012] Continuous casting: the production of steel billets using the continuous casting process;

[0013] Rolling: Hot rolling of steel billets to form the required expansion sleeve specifications;

[0014] Heat treatment: The rolled steel pipe is quenched and tempered to obtain the expansion sleeve.

[0015] In one specific embodiment, optionally, the rolling process includes hot rolling of the steel billet at a temperature of 800–1000°C.

[0016] In one specific embodiment, optionally, the quenching temperature is 850–900°C and the quenching time is 30–40 min.

[0017] In one specific embodiment, optionally, the tempering temperature is 750–800°C and the tempering time is 120–150 min.

[0018] Thirdly, this application also relates to the application of the aforementioned expansion casing in oil and gas development.

[0019] In summary, the advantages of this application over the prior art include:

[0020] Through repeated proportioning experiments, this application has discovered that within a certain range of material formulations and heat treatment processes, the yield strength of the expansion casing material after expansion can reach over 500 MPa. Simultaneously, under the condition of a 5% expansion rate, the expansion pressure is reduced to below 15 MPa, with an internal pressure resistance index above 45 MPa and an external extrusion resistance index above 16 MPa. This allows the expansion casing material to balance post-expansion strength and expandability. It resolves the contradiction between post-expansion strength and expandability in existing expansion casing materials, improving the service life and construction safety of expansion casings in the petroleum industry. Detailed Implementation

[0021] The present application will be described in detail below through specific embodiments and comparative examples:

[0022] Example 1

[0023] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0024] C: 0.22%, Si: 0.2%, Mn: 1.2%, P: 0.01%, S: 0.009%, Cr: 0.3%, Mo: 0.2%, Ni: 0.5%, V: 0.06%, Nb: 0.01%, with the remainder being Fe.

[0025] The method for preparing the expansion sleeve in this embodiment includes the following steps:

[0026] (1) Smelting: According to the above element ratio, the chemical elements of the material are put into the smelting furnace for smelting to obtain uniform molten steel.

[0027] (2) Continuous casting: Steel billets are produced using the continuous casting process.

[0028] (3) Rolling: The steel billet is hot rolled at 800℃ to form the required expansion sleeve specifications.

[0029] (4) Heat treatment: The rolled steel pipe is quenched at 850℃ for 30 min. Then, it is tempered at 760℃ for 120 min to obtain the expansion sleeve.

[0030] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0031] Table 1. Test results of expansion sleeve management performance in Example 1

[0032]

[0033] Example 2

[0034] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0035] C: 0.2%, Si: 0.25%, Mn: 1%, P: 0.008%, S: 0.009%, Cr: 0.2%, Mo: 0.25%, Ni: 0.6%, V: 0.055%, Nb: 0.02%, with the remainder being Fe.

[0036] The method for preparing the expansion sleeve in this embodiment includes the following steps:

[0037] (1) Smelting: According to the above element ratio, the chemical elements of the material are put into the smelting furnace for smelting to obtain uniform molten steel.

[0038] (2) Continuous casting: Steel billets are produced using the continuous casting process.

[0039] (3) Rolling: The steel billet is hot rolled at 900℃ to form the required expansion sleeve specifications.

[0040] (4) Heat treatment: The rolled steel pipe is quenched at 880℃ for 30 min. Then, it is tempered at 770℃ for 120 min to obtain the expansion sleeve.

[0041] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0042] Table 2. Test results of expansion sleeve management performance in Example 2

[0043]

[0044] Example 3

[0045] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0046] C: 0.22%, Si: 0.2%, Mn: 1.2%, P: 0.01%, S: 0.006%, Cr: 0.3%, Mo: 0.3%, Ni: 0.6%, V: 0.06%, Nb: 0.02%, with the remainder being Fe.

[0047] The method for preparing the expansion sleeve in this embodiment includes the following steps:

[0048] (1) Smelting: According to the above element ratio, the chemical elements of the material are put into the smelting furnace for smelting to obtain uniform molten steel.

[0049] (2) Continuous casting: Steel billets are produced using the continuous casting process.

[0050] (3) Rolling: The steel billet is hot rolled at 1000℃ to form the required expansion sleeve specifications.

[0051] (4) Heat treatment: The rolled steel pipe is quenched at 900℃ for 30 min. Then, it is tempered at 770℃ for 120 min to obtain the expansion sleeve.

[0052] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0053] Table 3. Test results of expansion sleeve management performance in Example 3

[0054]

[0055]

[0056] Example 4

[0057] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0058] C: 0.15%, Si: 0.3%, Mn: 1.4%, P: 0.01%, S: 0.02%, Cr: 0.1%, Mo: 0.5%, Ni: 1.5%, V: 0.08%, Nb: 0.04%, with the remainder being Fe.

[0059] The preparation method of the expansion sleeve in this embodiment is the same as that in Embodiment 1.

[0060] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0061] Table 4. Test results of expansion sleeve management performance in Example 4

[0062]

[0063] Example 5

[0064] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0065] C: 0.18%, Si: 0.4%, Mn: 1.5%, P: 0.02%, S: 0.01%, Cr: 0.15%, Mo: 0.4%, Ni: 1%, V: 0.1%, Nb: 0.05%, with the remainder being Fe.

[0066] The preparation method of the expansion sleeve in this embodiment is the same as that in Embodiment 1.

[0067] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0068] Table 5. Test results of expansion sleeve management performance in Example 5

[0069]

[0070] Example 6

[0071] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0072] C: 0.3%, Si: 0.5%, Mn: 1.5%, P: 0.005%, S: 0.005%, Cr: 1%, Mo: 0.2%, Ni: 1.6%, V: 0.05%, Nb: 0.02%, with the remainder being Fe.

[0073] The preparation method of the expansion sleeve in this embodiment is the same as that in Embodiment 1.

[0074] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0075] Table 6. Test results of expansion sleeve management performance in Example 6

[0076]

[0077] Example 7

[0078] The expansion sleeve in this embodiment comprises the following chemical elements by mass percentage:

[0079] C: 0.25%, Si: 0.4%, Mn: 1.3%, P: 0.01%, S: 0.01%, Cr: 0.5%, Mo: 0.4%, Ni: 2%, V: 0.07%, Nb: 0.03%, with the remainder being Fe.

[0080] The preparation method of the expansion sleeve in this embodiment is the same as that in Embodiment 1.

[0081] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0082] Table 7. Test results of expansion sleeve management performance in Example 7

[0083]

[0084] Comparative Example 1

[0085] The expansion sleeve in this comparative example comprises the following chemical elements by mass percentage:

[0086] C: 0.4%, Si: 0.25%, Mn: 1.3%, P: 0.02%, S: 0.01%, Cr: 0.05%, Mo: 0.1%, Ni: 0.4%, V: 0.04%, Nb: 0.008%, with the remainder being Fe.

[0087] The preparation method of the expansion sleeve in this comparative example is the same as that in Example 1.

[0088] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0089] Table 8 shows the test results of the expansion sleeve management performance in Comparative Example 1.

[0090]

[0091] Comparative Example 2

[0092] The expansion sleeve in this comparative example comprises the following chemical elements by mass percentage:

[0093] C: 0.3%, Si: 0.25%, Mn: 0.9%, P: 0.02%, S: 0.02%, Cr: 1.2%, Mo: 0.6%, Ni: 2.5%, V: 0.2%, Nb: 0.006%, with the remainder being Fe.

[0094] The preparation method of the expansion sleeve in this comparative example is the same as that in Example 1.

[0095] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0096] Table 9 shows the test results of the expansion sleeve management performance in Comparative Example 2.

[0097]

[0098] Comparative Example 3

[0099] The expansion sleeve in this comparative example comprises the following chemical elements by mass percentage:

[0100] C: 0.1%, Si: 0.2%, Mn: 3.6%, P: 0.006%, S: 0.006%, Mo: 0.3%, V: 0.06%, Nb: 0.02%, Ti: 0.001%, the remainder being Fe.

[0101] In the preparation method of the expansion sleeve, the quenching temperature is 700℃, the quenching time is 30min, the tempering temperature is 620℃, and the tempering time is 120min.

[0102] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0103] Table 10 shows the test results of the expansion sleeve management performance in Comparative Example 3.

[0104]

[0105] Comparative Example 4

[0106] The expansion sleeve in this comparative example comprises the following chemical elements by mass percentage:

[0107] C: 0.05%, Si: 0.28%, Mn: 4%, P: 0.009%, S: 0.003%, Mo: 0.5%, with the remainder being Fe.

[0108] In the preparation method of the expansion sleeve, the quenching temperature is 720℃, the quenching time is 30min, the tempering temperature is 650℃, and the tempering time is 120min.

[0109] Various physical and chemical properties of the expansion sleeve were tested, and the test results are shown in the table below:

[0110] Table 11 Results of expansion sleeve management performance tests in Comparative Example 4

[0111]

[0112] Comparing Tables 1-7 and 8-9, it can be seen that, compared to Comparative Examples 1-2, by using a certain range of material formulations and heat treatment processes, the yield strength of the expansion sleeve material after expansion can reach over 500 MPa, while the expansion pressure is reduced to below 15 MPa under a 5% expansion rate. This allows the expansion sleeve material to balance both post-expansion strength and expandability. In Comparative Examples 1 and 2, increasing the amount of C and changing the amounts of Cr, Mo, Ni, V, and Nb significantly improved the strength of the expansion sleeve after expansion, with the yield strength reaching 600 MPa. However, the expansion pressure was high and fluctuated widely. Specifically, the expansion pressure in Comparative Example 1 reached 16-25 MPa, and in Comparative Example 2, it reached 15-23 MPa.

[0113] Comparing Tables 1-5 with Table 10, it can be seen that in Comparative Example 3, although the expansion sleeve obtained by replacing Cr and Ni with Ti and increasing the amount of Mn has higher yield strength and tensile strength, its toughness is relatively poor. The expansion pressure reaches over 20 MPa and is unstable, making it prone to cracking. Further comparison in Table 11 shows that although the expansion tube in Comparative Example 4 has lower expansion pressure, its yield strength and tensile strength are relatively low. The expansion tube's resistance to internal pressure and external extrusion after expansion is difficult to reach the level of Examples 1-5, making it difficult to meet the requirements of engineering applications.

[0114] Furthermore, comparing Tables 1-3 with Tables 4-5, it can be seen that the expansion pressure of the expansion sleeve in Examples 4-5 is lower than that in Examples 1-3. This indicates that by further controlling the content of each element within a certain range, the expansion sleeve can achieve superior expandability while meeting certain post-expansion strength requirements.

[0115] Furthermore, comparing Tables 1-3 with Tables 6-7, it can be seen that, compared to Examples 1-3, the expansion sleeves in Examples 6-7 exhibit yield strength and tensile strength exceeding 550 MPa after expansion, an internal pressure resistance index of approximately 52 MPa, and an external extrusion resistance index of approximately 22 MPa. This indicates that by further controlling the content of each element within a certain range, the expansion sleeve can achieve superior post-expansion strength under an expansion pressure below 15 MPa.

[0116] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," just as "comprising" is interpreted as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A high-pressure-bearing expansion sleeve with low expansion force, characterized in that, It comprises, by mass percentage, the following chemical elements: C: 0.15%–0.3%, Si: 0.2%–0.5%, Mn: 1%–1.5%, P≤0.02%, S≤0.02%, Cr: 0.1%–1%, Mo: 0.2%–0.5%, Ni: 0.5%–2%, V: 0.05%–0.1%, Nb: 0.01%–0.05%, and the balance Fe.

2. The expansion sleeve according to claim 1, characterized in that, It comprises, by mass percentage, the following chemical elements: C: 0.2%–0.22%, Si: 0.2%–0.25%, Mn: 1%–1.2%, P: 0.008%–0.01%, S: 0.006%–0.009%, Cr: 0.2%–0.3%, Mo: 0.2%–0.3%, Ni: 0.5%–0.6%, V: 0.055%–0.06%, Nb: 0.01%–0.02%, and the balance Fe.

3. The expansion sleeve according to claim 1, characterized in that, It comprises, by mass percentage, the following chemical elements: C: 0.15%–0.18%, Si: 0.3%–0.4%, Mn: 1.4%–1.5%, P: 0.01%–0.02%, S: 0.01%–0.02%, Cr: 0.1%–0.15%, Mo: 0.4%–0.5%, Ni: 1%–1.5%, V: 0.08%–0.1%, Nb: 0.04%–0.05%, and the balance Fe.

4. The expansion sleeve according to claim 1, characterized in that, It comprises, by mass percentage, the following chemical elements: C: 0.25%–0.3%, Si: 0.4%–0.5%, Mn: 1.3%–1.5%, P: 0.005%–0.01%, S: 0.005%–0.01%, Cr: 0.5%–1%, Mo: 0.2%–0.4%, Ni: 1.6%–2%, V: 0.05%–0.07%, Nb: 0.02%–0.03%, and the balance Fe.

5. The expansion sleeve according to any one of claims 1 to 4, characterized in that, The expansion sleeve has an expansion pressure of 7-14 MPa when the expansion rate is 5%.

6. A method for preparing a low-expansion-force, high-pressure-bearing expansion sleeve according to any one of claims 1 to 5, characterized in that, include: Smelting: Chemical elements are added to a smelting furnace according to a set ratio to smelt steel and obtain uniform molten steel; Continuous casting: the production of steel billets using the continuous casting process; Rolling: Hot rolling of steel billets to form the required expansion sleeve specifications; Heat treatment: The rolled steel pipe is quenched and tempered to obtain the expansion sleeve.

7. The method according to claim 6, characterized in that, The rolling process includes hot rolling of the steel billet at a temperature of 800–1000°C.

8. The method according to claim 6, characterized in that, The quenching temperature is 850–900℃, and the quenching time is 30–40 min.

9. The method according to claim 6, characterized in that, The tempering treatment is performed at a temperature of 750–800°C for 120–150 minutes.

10. The application of the expansion casing according to any one of claims 1 to 5 in oil and gas development.

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