Cementing slurry composition, cementing slurry system and method for preparing and using the same

Abstract

The present application relates to a kind of cementing cement slurry compositions, cementing cement slurry system and its preparation method and application, the composition includes: 100 weight parts main material, 2-5 weight parts performance optimization agent, 0.1-1 weight parts accelerator, 0.1-2 weight parts fluid loss additive and 42-45 weight parts water;The main material is composed of fine cement and lightening agent, the lightening agent is nano silicon carbide micro powder, and the mass ratio of fine cement and nano silicon carbide micro powder is 95:5-40:60.The cementing cement slurry system is prepared from the cementing cement slurry composition.The cement slurry density can be changed according to the actual situation on site by adjusting the content of nano silicon carbide, the adjustable range is 1.90-1.21g / cm 3 , all can reach the performance index of traditional high-density cement slurry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas field exploitation, and particularly relates to a cementing slurry composition, a cementing slurry system and a preparation method and application thereof. BACKGROUND

[0002] A certain oilfield is rich in resources and is a typical low-permeability, low-pressure, low-abundance and low-yield oil and gas reservoir. The oilfield is mainly developed at low cost through cluster long horizontal section horizontal well cementing, perforating and fracturing. Due to the deep burial of the oil and gas reservoir, the multiple lost layers, the long open hole section of the horizontal section, the large circulation pressure consumption of the small wellbore size, the high fracturing modification pressure and large scale in the later stage, higher technical requirements and challenges are put forward for the cementing of the horizontal section of the horizontal well. With the progress of drilling technology, the cement slurry system prepared by ordinary cement cannot meet the increasingly harsh production needs of the field. Therefore, a cement slurry system formula and preparation method for cementing the horizontal section of an oil and gas well are researched and invented. SUMMARY

[0003] The present application uses the lightweight nanomaterial SiC with stable performance as a lightening agent for cement slurry, and simultaneously adds a performance optimizer compounded by carboxypropyl methyl cellulose, polyethylene micro powder, white latex and BFRP fiber, so that the low-density cement slurry has good rheological property and stability, and also has the compression resistance and toughness of high-density cement slurry.

[0004] The technical scheme adopted by the present application is as follows: a cementing slurry composition, which comprises: 100 parts by weight of a main material, 2-5 parts by weight of a performance optimizer, 0.1-1 parts by weight of a setting accelerator, 0.1-2 parts by weight of a fluid loss reducer and 42-45 parts by weight of water.

[0005] The main material is composed of fine cement and a lightening agent, the lightening agent is nano silicon carbide micro powder, and the mass ratio of the fine cement to the nano silicon carbide micro powder is 95:5-40:60.

[0006] Further, the fine cement is G-grade ordinary type calcium silicate cement clinker, and the density is 3.15 g / cm 3 ; the fineness distribution requirements are as follows: the proportion of cement particles with a particle size of ≤3 μm is 10%, the proportion of cement particles with a particle size of ≤32 μm is 50%, the proportion of cement particles with a particle size of ≤65 μm is 70%, and the proportion of cement particles with a particle size of ≤100 μm is 100%.

[0007] Further, the performance optimizer formula is composed of 20% mass parts of carboxypropyl methyl cellulose, 20% mass parts of polyethylene micro powder, 55-57% mass parts of white latex and 3-5% mass parts of basalt fiber reinforced plastic fiber; the polyethylene micro powder is composed of low-density polyethylene and high-density polyethylene with a mass ratio of 1:1, and the particle size of the low-density polyethylene and the high-density polyethylene is 500-1500 mesh.

[0008] Further, the accelerator is capsule controllable CaCl2.

[0009] Further, the nano-silicon carbide powder has a density of 0.11 g / cm 3 .

[0010] The application also relates to a cementing slurry system prepared from the cementing slurry composition.

[0011] Further, the cementing slurry system has an applicable temperature range of 0-100 DEG C, a density of 1.90-1.21 g / cm 3 , an API fluid loss of less than 50 mL, a 48h compressive strength of greater than or equal to 14 MPa, a 72h compressive strength of greater than or equal to 35 MPa, a thickening time of 1-10 h, an initial consistency of 22-28 Bc and a longitudinal density difference of less than 0.01 g / cm 3 .

[0012] The application also relates to a preparation method of the cementing slurry system.

[0013] The performance optimizing agent, the accelerator and the fluid loss reducer are added into the main material to obtain dry mixed material;

[0014] Water is further added into the dry mixed material to obtain the cementing slurry.

[0015] The main material is 100 parts by weight, the performance optimizing agent is 2-5 parts by weight, the accelerator is 0.1-1 part by weight, the fluid loss reducer is 0.1-2 parts by weight, and water is 42-45 parts by weight; the main material is composed of fine cement and a lightening agent, the lightening agent is nano-silicon carbide powder, and the mass ratio of the fine cement to the nano-silicon carbide powder is 95:5-40:60.

[0016] The application also relates to application of the cementing slurry system or the cementing slurry system prepared by the method to normal-temperature oil and gas wells, horizontal-section small-hole cementing, straight wells or directional wells.

[0017] The cementing slurry system formula designed by the application has the following beneficial effects:

[0018] 1. The cementing slurry has good rheological property, stability and controllability under different cementing slurry densities; meanwhile, the cementing slurry density can be changed by adjusting the content of the nano-silicon carbide powder according to the actual situation on site, and the adjustable range is 1.90-1.21 g / cm 3 , and the performance indexes of traditional high-density cementing slurry can be achieved;

[0019] 2. The system formula optimizes the particle size distribution range of cement clinker, appropriately increases the specific surface area of cement clinker, slows down the early cement hydration speed, improves rheological property, maintains the early consistency at about 22Bc, and enhances pumpability;

[0020] 3. The cementing slurry system formula uses a capsule controllable CaCl2 accelerator, so that the hydration and thickening reaction of the cement slurry can be controlled and optimized according to the actual construction site;

[0021] 4. The system formula adds a performance optimizer compounded by carboxypropyl methyl cellulose, polyethylene micro powder, white latex and BFRP fiber, which not only makes the low-density cement slurry have good rheological property and uniform stability, but also improves the cementing strength between the cement sheath, casing and formation, increases the compressive strength and toughness of the cement stone, reduces the permeability of the cement stone, and improves the corrosion resistance of the cement sheath, so as to improve the cementing quality of the horizontal section.

[0022] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the methods and systems particularly pointed out in the written description. DETAILED DESCRIPTION

[0023] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0024] The present application relates to a cementing slurry system prepared from a cementing slurry composition. The cementing slurry composition comprises: 100 parts by weight of a main material, 2-5 parts by weight of a performance optimizer, 0.1-1 parts by weight of an accelerator, 0.1-2 parts by weight of a fluid loss reducer, and 42-45 parts by weight of water; the main material is composed of fine cement and a lightening agent, the lightening agent is nano-silicon carbide micro powder, and the mass ratio of the fine cement to the nano-silicon carbide micro powder is 95:5-40:60.

[0025] Theoretical research shows that the fine cement is composed of cement particles of various gradations, the cement particles with a particle size of 10 microns or less have the fastest hydration speed, the cement particles with a particle size of 3-30 microns have the maximum activity, the cement particles with a particle size of 65-100 microns have relatively weak activity and slow hydration, and the cement particles with a particle size of more than 100 microns can only have surface hydration and play a role of packing material. Generally, the finer the cement is, the greater the specific surface area is, but the production cost of the cement is also increased; the fineness requirement of the ordinary type calcium silicate cement is that the specific surface area should be greater than 300 m 2 / kg according to the national regulation. In order to improve the cementation and early strength of the cement, it is necessary to improve the fineness of the cement and optimize the particle size distribution.

[0026] In the present application, the fine cement particle size distribution is shown in Table 1.

[0027] Table 1 fine cement particle size distribution

[0028] Particle size (μm) ≤3 ≤32 ≤65 ≤100 Interval distribution (%) 10 50 70 100

[0029] In Table 1, the proportion of the particles with a particle size of 3 microns or less accounts for 10%, too much or too little will affect the cementing strength of the cement slurry system; the proportion of the particles with a particle size of 32 microns or less accounts for 50%, the activity of this part of the cement particles is the maximum, the reaction is relatively sufficient when meeting water, and it is crucial to improve the cementation and early strength of the cement; the activity of the particles with a particle size of 65-100 microns is relatively weak, and the hydration is slow, but it is beneficial to the fluidity of the cement slurry system; the fine cement particle size distribution designed in Table 1 improves the total specific surface area and the initial hydration speed of the cement, and also improves the fluidity of the cement slurry system.

[0030] In the embodiment of the present application, the nano silicon carbide powder (product model DK-SIC-001) is a lightweight nano material with a bulk density of only 0.11 g / cm 3 As a key material of the cement slurry system formula, the proportion of the addition of the nano silicon carbide powder determines the density of the cement slurry. Experiments prove that when the water material mass ratio is 0.44, the relationship between the mass ratio of the cement and the nano silicon carbide powder and the density of the cement slurry is shown in Table 2.

[0031] Table 2 relationship between the mass ratio of the cement and the nano silicon carbide powder and the density of the cement slurry

[0032] Mass ratio of cement to nano-carbide silicon 90：10 80：20 70：30 60：40 50：50 40：60 Main material density (g / cm 3 )]]> 2.85 2.43 2.24 1.93 1.63 1.33 Cement paste density (g / cm 3 ) 1.82 1.66 1.62 1.50 1.37 1.21

[0033] In the embodiment of the present application, the performance optimization agent formula is composed of 20% mass parts of carboxypropyl methyl cellulose, 20% mass parts of polyethylene powder, 55-57% mass parts of white latex, and 3-5% mass parts of basalt fiber reinforced plastic fiber; the polyethylene powder is composed of low-density polyethylene and high-density polyethylene with a mass ratio of 1:1, and the particle size of the low-density polyethylene and the high-density polyethylene is 500-1500 mesh.

[0034] In the embodiment of the present application, the coagulant is CaCl2, the wall thickness of the capsule is adjustable, the wall thickness is 0.1-0.3mm, and the different particle sizes are 0.1mm-15mm; the different setting time of the cement slurry system in the field requires different wall thickness and pressure resistance parameters.

[0035] In the embodiment of the present application, the fluid loss reducer can be selected from various fluid loss reducers in the prior art, such as J-2B (ordinary type) oil well cement fluid loss reducer or polyacrylamide polymer; the water is pure water or fresh water used in the field without affecting the quality.

[0036] The second aspect of the embodiment of the present application relates to a preparation method of the cement slurry system, and the method comprises the following steps:

[0037] The performance optimization agent, the coagulant and the fluid loss reducer are added to the main material to perform first mixing to obtain dry mixed material;

[0038] Water is added to the dry mixed material to perform second mixing to obtain the cement slurry system; the main material is 100 parts by weight, the performance optimization agent is 2-5 parts by weight, the coagulant is 0.1-1 part by weight, the fluid loss reducer is 0.1-2 parts by weight, and the water is 42-45 parts by weight; the main material is composed of fine cement and a lightening agent, the lightening agent is nano silicon carbide powder, and the mass ratio of the fine cement to the nano silicon carbide powder is 95:5-40:60;

[0039] The application temperature range of the cement slurry system prepared by the above method is 0-100℃, the density of the cement slurry system is 1.90-1.21g / cm 3 , the API fluid loss is less than 50mL, the 48h compressive strength is 14MPa or above, the 72h compressive strength is 35MPa or above, the thickening time is adjustable and controllable within 1-10h, the initial consistency is 22-28Bc, and the longitudinal density difference is 0.01g / cm 3 .

[0040] The third aspect of the embodiment of the present application relates to the application of the above cement slurry system or the cement slurry system prepared by the above preparation method in normal temperature oil and gas wells, horizontal section small hole well cementing, straight wells or directional wells.

[0041] Example 1: Lightening agent nano silicon carbide powder dosage and evaluation test

[0042] The lightening agent nano silicon carbide powder dosage and the evaluation test results in example 1 are listed in table 1, and it can be seen from the data in table 3 that the cement slurry density is adjusted by adjusting the content of the lightening agent nano silicon carbide powder, but as the cement content in the main material decreases, the cement slurry density decreases, the longitudinal density difference appears, and the performance optimization material needs to be added.

[0043] Table 3 dosage of lightening agent nano-carbonized silicon micro-powder and evaluation test

[0044]

[0045]

[0046] Example 2: cement clinker particle size optimization test

[0047] The five sets of experimental data of the cement clinker particle size optimization test in Table 4 show that the optimal distribution range of the cement clinker fineness is: the proportion of particle size ≤ 100 μm is 100%, the proportion of particle size ≤ 65 μm is 70%, the proportion of particle size ≤ 32 μm is 50%, and the proportion of particle size ≤ 3 μm is 10%; when the cement clinker particle size is distributed in this range, the cement paste density is 1.21 g / cm 3 ; the initial consistency is 22Bc; and the thickening time is 18h; compared with the test results in the first to fourth groups, the initial consistency is reduced and the thickening time is prolonged.

[0048] Table 4 cement clinker particle size optimization test and results

[0049]

[0050]

[0051] Example 3: accelerator CaCl2 optimization test

[0052] Table 5 gives the test results of a typical low-density cement slurry system with a density of 1.37 g / cm 3 ; the optimal dosage of the accelerator for the cement slurry system is (0.4-1)% of the mass of the cement slurry system; and the experiment shows that the capsule controllable CaCl2 as the key control material is adjustable and controllable under simulated working conditions.

[0053] Table 5 accelerator CaCl2 optimization test and results

[0054]

[0055]

[0056] Example 4: fluid loss additive optimization test

[0057] As can be seen from the test results in Table 6, the dosage (0.2-1) parts by weight and the type of the conventional fluid loss additive do not change particularly, and the conventional fluid loss additive can meet the fluid loss requirement according to the conventional dosage.

[0058] Table 6 fluid loss additive optimization test and results

[0059]

[0060]

[0061]

[0062] Example 5: Optimization test of cement slurry system formulation

[0063] From the test results in Table 7, it can be seen that the performance optimization agent formulation (mass ratio) M is: carboxypropyl methyl cellulose 20% + polyethylene micro powder 20% + white latex (55-57)% + BFRP fiber (3-5)%, the polyethylene micro powder is composed of low density polyethylene and high density polyethylene with a mass ratio of 1:1, and the particle size of the low density polyethylene and the high density polyethylene is 500-1500 mesh. The results of multiple experiments in the early stage of this formulation have been applied and proved, and here the direct test application is described. When the added weight of the performance optimization agent is 2, the optimization effect has been shown, and the longitudinal density difference reaches 0.01 g / cm 3 The system stability is improved, and the 72h compressive strength is significantly increased. Considering economic factors, the general addition amount is between 2-5 parts by weight.

[0064] Table 7: Optimization test of cement slurry system formulation and results

[0065]

[0066]

[0067]

[0068]

[0069] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent replacements can be made to part of the technical features; and such modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A cement slurry composition, characterized in that, The composition comprises 100 parts by weight of a main material, 2-5 parts by weight of a performance optimization agent, 0.1-1 parts by weight of a coagulant, 0.1-2 parts by weight of a fluid loss agent, and 42-45 parts by weight of water; The main material is composed of fine cement and a lightening agent, the lightening agent is nano-silicon carbide powder, and the mass ratio of the fine cement to the nano-silicon carbide powder is 95:5-40:60; The fine cement is G-grade ordinary type calcium silicate cement clinker, with a density of 3.15 g / cm 3 ; the fineness distribution requirements are as follows: the proportion of cement particles with a particle size of ≤3 µm is 10%, the proportion of cement particles with a particle size of ≤32 µm is 50%, the proportion of cement particles with a particle size of ≤65 µm is 70%, and the proportion of cement particles with a particle size of ≤100 µm is 100%. The performance optimization agent is composed of 20% by mass of carboxypropyl methyl cellulose, 20% by mass of polyethylene powder, 55-57% by mass of white latex, and 3-5% by mass of basalt fiber reinforced plastic fiber; the polyethylene powder is composed of low-density polyethylene and high-density polyethylene at a mass ratio of 1:1, and the particle size of the low-density polyethylene and the high-density polyethylene is 500-1500 mesh; The coagulant is a capsule controllable CaCl2.

2. The cement slurry composition of claim 1, wherein, The nano-silicon carbide powder has a density of 0.11 g / cm 3 .

3. A cement slurry system characterized by, The cementing slurry system is prepared from the cementing slurry composition of any one of claims 1-2.

4. The cementing slurry system of claim 3, wherein, The applicable temperature range of the cement slurry system is 0-100 DEG C, the density of the cement slurry system for well cementation is 1.90-1.21 g / cm 3 ; API fluid loss is less than 50 mL; 48h compressive strength is greater than or equal to 14 MPa; 72h compressive strength is greater than or equal to 35 MPa; thickening time is 1-10 h; initial consistency is 22-28 Bc; longitudinal density difference is less than 0.01 g / cm 3 .

5. A method of preparing the cement slurry system of claim 3 or 4, characterized in that, The method comprises the following steps: The performance optimization agent, the coagulant, and the fluid loss agent are added to the main material for mixing to obtain a dry mixture; Water is further added to the dry mixture for mixing and stirring to obtain the cementing slurry. The main material is 100 parts by weight, the performance optimization agent is 2-5 parts by weight, the coagulant is 0.1-1 parts by weight, the fluid loss agent is 0.1-2 parts by weight, and the water is 42-45 parts by weight; the main material is composed of fine cement and a lightening agent, the lightening agent is nano-silicon carbide powder, and the mass ratio of the fine cement to the nano-silicon carbide powder is 95:5-40:

60.

6. The cementing slurry system of claim 3 or 4, or the cementing slurry system prepared by the method of claim 5 is applied in normal temperature oil and gas wells, horizontal section small hole cementing, straight wells, or directional wells.

Images