Low-cost and high-water-demand reinforcing material for oil well cement
By using low-cost, high-water-required reinforced materials prepared with ultrafine cement, bentonite and other materials, the problems of low-strength, poor stability and high cost in the early stages of low-density cement slurry are solved, and efficient preparation and performance improvement of low-density cement slurry with a density of 1.20 to 1.50g/cm3 are achieved.
Patent Information
- Application Number
- CN202311366707.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-20
- Publication Date
- 2025-04-22
AI Technical Summary
The existing low-density cement slurry has low strength, poor stability in the early stage during the cementing process, and is relatively high in cost, making it difficult to meet the sealing requirements of low-pressure leakage-prone formations.
Low-cost, high-water-required reinforced materials including ultrafine cement, bentonite, ultrafine silicon powder, fly ash, mica powder, alkali slag, diatomaceous earth and floating beads are used to prepare low-density cement slurry with a density of 1.20 to 1.50g/cm3 by expanding the liquid-solid ratio.
It achieves improved early strength and stability in low-density cement slurry, while significantly reducing costs. Compared with traditional hollow microbead systems, the cost can be reduced by more than 70%.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of drilling, and in particular to a low-cost, high-water-demand reinforcing material for oil well cement. Background Art
[0002] All oil fields strictly require that the entire well section be sealed and cement slurry be returned to the ground, which undoubtedly results in a large amount of low-density cement slurry used, leading to higher cementing costs. At the same time, the exploration and development costs are greatly reduced under the "low oil price" market environment. Therefore, the contradiction between the "high performance" and "low cost" of low-density cement slurry becomes more prominent and needs to be resolved urgently.
[0003] There are two relatively mature technologies for low-density cement slurry: one is to increase the liquid-solid ratio. Generally, sticky solid inorganic and organic highly absorbent materials and lightweight fillers are added, such as bentonite, diatomaceous earth, expanded perlite, etc. The second is to add glass microspheres, which can replace part of the cement to reduce the density by relying on the low density of the material itself. Such as fly ash, floating beads, hollow microspheres, etc. Generally, the density of low-density systems has a minimum limit, such as the minimum density of bentonite cement slurry is 1.60g / cm 3 The minimum density of diatomite cement slurry is 1.50g / cm 3 The minimum density of fly ash cement slurry is 1.55g / cm 3 The minimum density of floating bead cement slurry is
[0004] 1.38g / cm 3 When the cement slurry is lower than the above value, the performance is poor, especially the early compressive strength is low. According to the cementing technical specifications, the 24-48h compressive strength of the cement stone in the production casing non-target layer is not less than 7MPa. The above system is difficult to meet the requirements of one-time return and full well sealing in low-pressure and leaky formations. The cement slurry of the artificial hollow microsphere system has better performance and lower density, but the cost is high and it is difficult to promote and apply. Summary of the invention
[0005] The present application provides a low-cost, high-water-demand reinforcing material for oil well cement, which can solve the problems of high cost of low-density and ultra-low-density cement slurry systems, poor stability of conventional low-density and ultra-low-density conventional cement slurry systems, and low early strength.
[0006] This application adopts the following technical solutions:
[0007] The present application provides a low-cost, high-water-demand reinforcing material for oil well cement, comprising the following materials in parts by weight: 30 to 40 parts of ultrafine cement, 25 to 30 parts of bentonite, 30 to 40 parts of ultrafine silica powder, 10 to 20 parts of fly ash, 10 parts of mica powder, 20 parts of alkali residue, 10 parts of diatomaceous earth, and 0-60 parts of floating beads.
[0008] Furthermore, the ultrafine cement includes the following materials in parts by weight: 60 to 80 parts of cement with a particle size distribution of 1 to 5 μm, and 20 to 40 parts of cement with a particle size distribution of 5 to 10 μm.
[0009] Furthermore, the density of bentonite is 2.60-2.70 g / cm 3 , water content ≤3%, average particle size 50~75μm.
[0010] Furthermore, the density of ultrafine silicon powder is 2.50-2.60 g / cm 3 , average particle size 0.1~0.3μm.
[0011] Furthermore, the density of fly ash is 2.50-2.60 g / cm 3 , loss on ignition 1% to 2%, particle size range 0.5 to 50 μm.
[0012] Furthermore, the density of mica powder is 2.60-2.70 g / cm 3 , the average particle size is 10 to 15 μm.
[0013] Furthermore, the particle size of the alkali residue is in the range of 5 to 30 μm.
[0014] Furthermore, the density of diatomaceous earth is 1.90 to 2.30 g / cm 3 , the average particle size is 15 to 25 μm.
[0015] Compared with the prior art, this application has the following beneficial effects:
[0016] The low-cost high-water-demand reinforcing material for oil well cement provided in this application can be used to prepare a high-water-cement low-density cement slurry, which has good stability, high early strength and low cost. The water demand of the material in this application is 1.50-1.70, and can be prepared into a liquid-to-solid ratio of 0.94-1.36 and a density of
[0017] 1.20~1.50g / cm 3 The low-density cement slurry has a compressive strength of >8MPa at 60℃ / 24h and a compressive strength of 10MPa or more at 72h. The material of this application mainly solves the problems of low early strength, poor slurry fluidity and poor stability of the existing low-density cement slurry for cementing. At the same time, the raw materials are widely available and inexpensive. The prepared 1.20g / cm 3 Ultra-low density cement slurry compared to traditional hollow microspheres 1.20g / cm 3 The cost of cement slurry system is reduced by more than 70%, which can adapt to the current low-cost strategy of oil and gas exploration. DETAILED DESCRIPTION
[0018] The technical methods in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.
[0019] The embodiments of the present application provide a low-cost, high-water-demand reinforcing material for oil well cement, comprising the following materials in parts by weight: 30 to 40 parts of ultrafine cement, 25 to 30 parts of bentonite, 30 to 40 parts of ultrafine silica powder, 10 to 20 parts of fly ash, 10 parts of mica powder, 20 parts of alkali slag, 10 parts of diatomaceous earth, and 0-60 parts of floating beads.
[0020] The dosage of ultrafine cement can be 30, 35, or 40 parts. The ultrafine cement includes the following materials by weight: 60 to 80 parts of cement with a particle size distribution of 1 to 5 μm, and 20 to 40 parts of cement with a particle size distribution of 5 to 10 μm.
[0021] The dosage of bentonite can be 25, 28, or 30 parts. The density of bentonite is 2.60 to 2.70 g / cm 3 , water content ≤3%, average particle size 50~75μm.
[0022] The dosage of ultrafine silicon powder can be 30, 35, or 40 parts. The density of ultrafine silicon powder is 2.50 to 2.60 g / cm 3 , average particle size 0.1~0.3μm.
[0023] The dosage of fly ash can be 10, 15, or 20 parts. The density of fly ash is 2.50 to 2.60 g / cm 3 , loss on ignition 1% to 2%, particle size range 0.5 to 50 μm.
[0024] The density of mica powder is 2.60~2.70g / cm 3 , the average particle size is 10 to 15 μm.
[0025] The particle size of the alkali residue ranges from 5 to 30 μm.
[0026] The density of diatomaceous earth is 1.90~2.30g / cm 3 , the average particle size is 15 to 25 μm.
[0027] The dosage of floating beads can be 0, 20, 40, or 60 parts.
[0028] The low-cost high-water-demand reinforcing material for oil well cement provided in the present application can be used to prepare 1.20-1.60 g / cm 3Low-density cement slurry for cementing reduces costs by increasing the liquid-to-solid ratio, and the raw materials are widely available and inexpensive. By introducing active substances such as ultrafine cement, ultrafine silica powder and other components and compounding them in a certain ratio, the components can interact with each other and achieve close stacking, so that the cement slurry still has high strength and stability at a high liquid-to-solid ratio. This application aims to reduce costs and take performance into consideration. It uses highly absorbent, highly active, ultrafine materials to develop a low-cost, high-water-demand reinforcing material for oil well cement, which greatly reduces the cost of cement slurry and improves the performance of cement slurry. Under the premise that the performance difference is not much, the cost can be reduced by more than 70% compared to the hollow microsphere low-density system.
[0029] The following is a detailed description with reference to specific embodiments:
[0030] Example 1
[0031] Weigh 100 parts by weight of G-grade cement, 40 parts by weight of ultrafine cement, 30 parts by weight of bentonite, 40 parts by weight of ultrafine silica powder, 10 parts by weight of fly ash, 10 parts by weight of mica powder, 20 parts by weight of alkali residue, 10 parts by weight of diatomaceous earth, 60 parts by weight of floating beads, and 420 parts by weight of water to prepare a cement slurry of 1.20 g / cm according to the preparation method of cement slurry specified in GB19139-2012 Test Methods for Oil Well Cement. 3 Low cost low density cement slurry.
[0032] The performance of the cement slurry prepared with the low-cost, high-water-demand reinforcement material was evaluated according to the test method specified in GB / T 19139-2012 “Test Methods for Oil Well Cement”. The experimental results are shown in Table 1.
[0033] Table 1 1.20g / cm under different conditions 3 Evaluation results of low-density cement slurry
[0034]
[0035] Example 2
[0036] Weigh 100 parts by weight of G-grade cement, 40 parts by weight of ultrafine cement, 30 parts by weight of bentonite, 40 parts by weight of ultrafine silica powder, 10 parts by weight of fly ash, 10 parts by weight of mica powder, 20 parts by weight of alkali residue, 10 parts by weight of diatomaceous earth, 20 parts by weight of floating beads, and 380 parts by weight of water to prepare a cement slurry of 1.30 g / cm according to the preparation method of cement slurry specified in GB19139-2012 Test Methods for Oil Well Cement. 3 Nano-based low-density cement paste.
[0037] The performance of the cement slurry prepared with the low-cost, high-water-demand reinforcement material was evaluated according to the test method specified in GB / T 19139-2012 “Test Methods for Oil Well Cement”. The experimental results are shown in Table 2.
[0038] Table 2 1.30g / cm under different conditions 3 Evaluation results of low-density cement slurry
[0039]
[0040] Example 3
[0041] Weigh 100 parts by weight of G-grade cement, 30 parts by weight of ultrafine cement, 25 parts by weight of bentonite, 30 parts by weight of ultrafine silica powder, 20 parts by weight of fly ash, 10 parts by weight of mica powder, 20 parts by weight of alkali residue, 10 parts by weight of diatomaceous earth, and 300 parts by weight of water to prepare a cement slurry of 1.40 g / cm2 according to the preparation method of cement slurry specified in GB19139-2012 Test Methods for Oil Well Cement. 3 Nano-based low-density cement paste.
[0042] The performance of the cement slurry prepared with the low-cost, high-water-demand reinforcement material was evaluated according to the test method specified in GB / T 19139-2012 “Test Methods for Oil Well Cement”. The experimental results are shown in Table 3.
[0043] Table 3 1.40g / cm under different conditions 3 Evaluation results of low-density cement slurry
[0044]
[0045] Example 4
[0046] Weigh 100 parts by weight of G-grade cement, 30 parts by weight of ultrafine cement, 25 parts by weight of bentonite, 30 parts by weight of ultrafine silica fume, 20 parts by weight of fly ash, 10 parts by weight of mica powder, 20 parts by weight of alkali residue, 10 parts by weight of diatomaceous earth, and 230 parts by weight of water, and prepare a cement slurry of 1.50 g / cm according to the preparation method of cement slurry specified in GB19139-2012 Test Methods for Oil Well Cement. 3 Nano-based low-density cement paste.
[0047] The performance of the cement slurry prepared with the low-cost, high-water-demand reinforcement material was evaluated according to the test method specified in GB / T 19139-2012 “Test Methods for Oil Well Cement”. The experimental results are shown in Table 4.
[0048] Table 4 1.50g / cm under different conditions 3 Evaluation results of low-density cement slurry
[0049]
[0050] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and the scope of protection claimed in the present application is defined by the attached claims, description and their equivalents.
[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.
Claims
1. A low-cost, high-water-demand reinforcing material for oil well cement, characterized in that: Including the following materials by weight: 30-40 parts of ultrafine cement, 25-30 parts of bentonite, 30-40 parts of ultrafine silica powder, 10-20 parts of fly ash, 10 parts of mica powder, 20 parts of alkali slag, 10 parts of diatomaceous earth, and 0-60 parts of floating beads.
2. The low-cost high-water-demand reinforced material according to claim 1, characterized in that: The ultrafine cement comprises the following materials by weight: 60 to 80 parts of cement with a particle size distribution of 1 to 5 μm, and 20 to 40 parts of cement with a particle size distribution of 5 to 10 μm.
3. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The density of the bentonite is 2.60-2.70 g / cm 3 , water content ≤3%, average particle size 50~75μm.
4. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The density of the ultrafine silicon powder is 2.50-2.60 g / cm 3 , average particle size 0.1~0.3μm.
5. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The density of the fly ash is 2.50-2.60 g / cm 3 , loss on ignition 1% to 2%, particle size range is 0.5 to 50 μm.
6. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The density of the mica powder is 2.60-2.70 g / cm 3 , the average particle size is 10 to 15 μm.
7. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The particle size of the alkali residue is in the range of 5 to 30 μm.
8. The low-cost high-water-demand reinforcement material according to claim 1, characterized in that: The density of the diatomaceous earth is 1.90-2.30 g / cm 3 , the average particle size is 15 to 25 μm.