Profile control design method suitable for horizontal fractured reservoir

Abstract

A profile control design method suitable for a horizontal fractured reservoir belongs to the technical field of oil-gas field development, and comprises the following steps: S1, explaining formation parameters according to profile control well pressure drop test data, establishing a mathematical model based on the explained parameters, calculating fracture opening data, and realizing precision of profile control parameter calculation; s2, optimizing a profile control agent system and a slug combination mode, selecting a gel and water-swelling particle system with high plugging strength, and adopting a self-developed phenolic gel IV system; s3, the injection displacement matched with the properties of the profile control agent and the proper injection pressure change range are designed; and S4, on the basis of the profile control process parameter optimization method, a profile control design technical thought suitable for the horizontal fractured reservoir is achieved. According to the injection parameter optimization method for profile control of the horizontal fractured reservoir, effective plugging of a horizontal fractured dominant channel is achieved, the water flooding sweep efficiency is improved, and field application is guided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas field development, and particularly relates to a design method suitable for profile control of horizontal fractured reservoirs. BACKGROUND

[0002] With the increasing proportion of fractured reservoirs in the exploration and development of reservoir types, the use of hydraulic fracturing stimulation measures is becoming more and more frequent. In the process of hydraulic fracturing, the fracture initiation first overcomes the effect of the ground stress on the formation rock. Due to the different size relationships of the initial three ground stresses of the formation, vertical fractures or horizontal fractures may be formed. General research shows that the hydraulic fracture will expand along the direction of the maximum principal stress and perpendicular to the direction of the minimum principal stress. In the case of a vertical well, the hydraulic fracture is located in the vertical plane, and the fracture surface is parallel to the maximum horizontal principal stress and perpendicular to the minimum horizontal principal stress. However, in shallow reservoirs, due to the relatively large tectonic stress, the hydraulic fracture is likely to be in the horizontal plane. Therefore, the research on horizontal fractures is less, especially in the field of profile control of horizontal fractured reservoirs.

[0003] By analyzing the pressure field of the injection-production system, the pressure difference is mainly reflected in the plane direction, and the vertical direction is relatively weak, which leads to the fact that the seepage velocity in the plane direction is much larger than that in the vertical direction. The large seepage velocity in the plane direction makes it extremely difficult to plug the horizontal fractures formed by hydraulic fracturing near the injection well. Therefore, how to quantitatively identify the horizontal fractures, increase the plugging strength of the horizontal fractures, and reduce the high conductivity of the horizontal fractures is the key to the profile control of horizontal fractured reservoirs.

[0004] Before the present application, the existing profile control design method mainly uses the combination of gel carrying particles. This method aims to plug the fractures by using the gel carrying particle system to reduce the high conductivity of the fractures. However, due to the need for high reduction of the pore and permeability of the fracture system to plug the horizontal fractures, the conventional design method system and the dosage parameter optimization method do not have obvious effect on improving the fracture pore filling volume, the plugging strength is low, which leads to the problems of unobvious increase of the injection water pressure after profile control, un-reduction of the water cut, and poor overall profile control process effect. SUMMARY

[0005] In order to solve the above problems, the present application provides a design method suitable for profile control of horizontal fractured reservoirs, which comprises the following steps:

[0006] S1, according to the formation parameters such as inner and outer zone permeability, inner zone radius and formation coefficient obtained by interpreting the pressure drop test data of the profile control well, a mathematical model is established based on the interpreted parameters, and fracture opening data is calculated to realize the accuracy of profile control parameter calculation;

[0007] S2, the profile control agent system and the combination mode of the slug are optimized, the gel and the water-absorbing and swelling particle system with high plugging strength are selected, the self-developed phenolic aldehyde gel IV system is used, the ratio is 0.2%-0.3% of polyacrylamide, 0.1%-0.2% of polyformaldehyde, 0.05%-0.10% of m-benzene diol and 0.05%-0.15% of ammonium chloride, and the preferred ratio is 0.25% of polyacrylamide, 0.15% of polyformaldehyde, 0.05% of m-benzene diol and 0.08% of ammonium chloride;

[0008] S3, and the injection displacement matching the property of the profile control agent and the suitable injection pressure variation range are designed;

[0009] S4, the profile control design technical idea suitable for the horizontal fractured reservoir is realized based on the profile control process parameter optimization method.

[0010] Further, the horizontal fractured reservoir profile control parameter optimization method comprises the following steps:

[0011] S11, the well testing interpretation is performed on the pressure drop data of the injection well, the pressure drop data is interpreted by using the double-zone composite percolation model, and the data of the inner zone permeability, the outer zone permeability and the inner zone radius are obtained.

[0012] Further, the horizontal fractured reservoir profile control parameter optimization method further comprises the following steps:

[0013] S12, the plugging range is determined based on the variation rate of the pressure gradient in the near wellbore zone, and the volume method is used to calculate the required amount of the profile control agent.

[0014] Further, the horizontal fractured reservoir profile control parameter optimization method further comprises the following steps:

[0015] S13, the mathematical model among the pseudo-double medium permeability, the fracture opening and the fracture porosity is established, the inner zone permeability obtained by the well testing is used as the pseudo-double medium permeability, and the outer zone permeability is used as the matrix system permeability.

[0016] Further, the horizontal fractured reservoir profile control parameter optimization method further comprises the following steps:

[0017] S14, the mathematical model established is used to calculate the fracture opening.

[0018] Further, the horizontal fractured reservoir profile control parameter optimization method further comprises the following steps:

[0019] S15, based on the horizontal fracture plugging design, the three-stage gel carrying particle slug is used to realize the effective plugging of the horizontal fracture.

[0020] Further, the horizontal fractured reservoir profile control parameter optimization method further comprises the following steps:

[0021] S16, design matching profile control agent and injection displacement and injection pressure of the reservoir.

[0022] Further, the determination of the profile control agent action range is determined according to the interwell pressure gradient data, and the pressure gradient calculation formula is:

[0023]

[0024] In the formula, P e - formation pressure at the boundary, MPa

[0025] P wf - bottom hole flowing pressure, MPa

[0026] R e - supply radius, m

[0027] R w - wellbore radius, m

[0028] R - distance from injection and production wells, m.

[0029] Further, the profile control agent action range is determined according to the near wellbore pressure gradient change, and the distance with pressure gradient drop rate of more than 99% is taken as the profile control agent action range based on the pressure gradient calculation result.

[0030] Further, the amount of plugging agent is calculated by volume method, that is, the injected profile control agent can fill the profile control radius range, and the rubber particle density is taken as 1.25t / m 3 Calculate the mass of the particles.

[0031] Further, fracture opening degree calculation adopts chart method, and the fracture opening degree and pseudo dual medium permeability chart is drawn by using the calculation result, and the most suitable fracture opening degree is found, and the pseudo dual medium permeability calculation formula is:

[0032]

[0033] In the formula, b - fracture opening degree, cm

[0034] φ f - fracture porosity, %

[0035] K m - pseudo dual medium matrix permeability, D

[0036] - pseudo dual medium permeability, D.

[0037] Further, according to the previous profile control experience, the particle size and fracture opening degree matching range is established, and the opening degree 1-45um corresponds to 0.2-1mm, the opening degree 45-80um corresponds to 1-3mm, and the opening degree 80um and above corresponds to 3-5mm:

[0038] Further, the gel carrying particles is used to seal the horizontal fracture, and the amount of each stage is calculated by the following formula:

[0039] V1=50%*(V g +V p )

[0040] V2=30%*(V g +V p )

[0041] V3=20%*(V g +V p )

[0042] In the formula, V1 is the amount of the third stage profile control agent, m 3

[0043] V2 is the amount of the second stage profile control agent, m 3

[0044] V3 is the amount of the first stage profile control agent, m 3 .

[0045] Further, the injection pressure is designed: the pressure during construction is less than the formation fracture pressure

[0046] P 施工 <P 岩石破裂 -0.5.

[0047] Further, the injection rate is designed: different profile control agent systems adopt different injection rates:

[0048] The injection rate of the pre-protecting liquid (0.2% polymer) is 4m 3 / h

[0049] The injection rate of the gel carrying particles system is 3m 3 / h

[0050] The injection rate of the post-protecting liquid (0.2% polymer) is 4m 3 / h.

[0051] The beneficial effects of the present application are: the present application forms a horizontal fracture reservoir profile control design technical idea, establishes an injection parameter optimization method for horizontal fracture reservoir profile control, realizes effective sealing of horizontal fracture type dominant channels, improves water flooding sweep efficiency, and guides field application.

[0052] The present application is tested in 12 wells, the profile control parameter optimization and profile control scheme comprehensive design are carried out in the test well, the profile control agent is injected smoothly in the construction process, the pressure boosting amplitude reaches the expectation after the profile control, the follow-up tracking related production data of the effective oil well shows the obvious effect of liquid reduction, oil increase and water cut reduction, and has high practicability. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a double-zone composite percolation schematic diagram of near-wellbore zone of injection well;

[0054] Figure 2 It is a pressure gradient change diagram between injection and production wells;

[0055] Figure 3 It is a fracture opening and pseudo-double-medium percolation capacity diagram;

[0056] Figure 4 It is a plugging plug schematic diagram;

[0057] Figure 5 It is a production curve diagram of well group A of example 1;

[0058] Figure 6 It is a production curve diagram of well group B of example 2. DETAILED DESCRIPTION

[0059] In order to make the technical means and purposes adopted by the present application easy to understand, the present application is further described below in combination with specific embodiments, a profile control design method suitable for horizontal fractured reservoir, the profile control design technical idea of horizontal fractured reservoir: according to the formation parameter interpretation of the profile control well pressure drawdown test data, such as internal and external zone permeability, internal zone radius and formation coefficient, a mathematical model is established based on the interpreted parameters, fracture opening data is calculated, and the accuracy of profile control parameter calculation is realized. The profile control agent system and plug combination mode are optimized and optimized, the gel and water-absorbing and expanding particle system with high plugging strength are selected, the self-developed phenolic aldehyde gel IV system is used, the ratio is 0.2%-0.3% of polyacrylamide, 0.1%-0.2% of polyformaldehyde, 0.05%-0.10% of m-benzene diol and 0.05%-0.15% of ammonium chloride, the optimized ratio is 0.25% of polyacrylamide, 0.15% of polyformaldehyde, 0.05% of m-benzene diol and 0.08% of ammonium chloride. And the injection displacement matching the properties of the profile control agent and the suitable injection pressure change range are designed. The profile control process parameter optimization method is used to realize the profile control design technical idea suitable for horizontal fractured reservoir.

[0060] The profile control parameter optimization method of horizontal fractured reservoir: (1) the well test interpretation is carried out through the injection well pressure drawdown data, based on Figure 1 The double-zone composite percolation model is used to interpret the pressure drawdown data, the internal zone permeability, external zone permeability and internal zone radius and other data are obtained. (2) based onFigure 2 The rate of change of the middle pressure gradient in the near wellbore determines the plugging range, and the volume method is used to calculate the required amount of profile control agent. Figure 4 A three-stage gel carrying particle plug is designed to achieve effective plugging of the horizontal fracture.

[0061] DETAILED DESCRIPTION

[0062] (1) The profile control agent action range is determined according to the interwell pressure gradient data, and the pressure gradient calculation formula is:

[0063]

[0064] In the formula: P e - formation pressure at the boundary, MPa

[0065] P wf - bottom hole flowing pressure, MPa

[0066] R e - supply radius, m

[0067] R w - wellbore radius, m

[0068] R - distance from injection and production wells, m

[0069] (2) The profile control agent action range is determined according to the change of the near wellbore pressure gradient, and the pressure gradient calculation result is taken as the distance where the pressure gradient drop rate is more than 99% as the profile control agent action range. Figure 2

[0070] (3) The volume method is used to calculate the amount of plugging agent, that is, the injected profile control agent can fill the profile control radius range, and the rubber particle density is taken as 1.25 t / m 3 The particle mass is calculated.

[0071] (4) As shown in Figure 3 , the fracture opening degree is calculated using the chart method, and the fracture opening degree and pseudo-dual medium permeability chart is drawn using the calculation results to find the most suitable fracture opening degree. The pseudo-dual medium permeability calculation formula is:

[0072]

[0073] In the formula: b - fracture opening degree, cm

[0074] ​Fracture porosity, %

[0075] K m Pseudo dual media matrix permeability, D

[0076] Pseudo dual media permeability, D

[0077] (5) According to the previous experience of profile control, the matching range of particle size and fracture opening is established, and the opening of 1-45 um corresponds to 0.2-1 mm, the opening of 45-80 um corresponds to 1-3 mm, and the opening of 80 um and above corresponds to 3-5 mm:

[0078] (6) The three-stage gel carrying particles is designed to plug horizontal fractures, and the dosage calculation formula of each stage is:

[0079] V1=50% x (V g +V p )

[0080] V2=30% x (V g +V p )

[0081] V3=20% x (V g +V p )

[0082] V1-Third slug profile control agent dosage, m 3

[0083] V2-Second slug profile control agent dosage, m 3

[0084] V3-First slug profile control agent dosage, m 3

[0085] (7) Injection pressure design: the pressure during construction is less than the formation fracture pressure

[0086] P 施工 <P 岩石破裂 -0.5

[0087] (8) Injection rate design: different profile control agent systems use different injection rates 3 / h

[0088] Gel carrying particle system injection rate: 3m 3 / h

[0089] Post-protective fluid (0.2% polymer) injection rate: 4m 3 / h

[0090] Example 1:

[0091] As Figure 5 shown, the water cut of the effective oil well around the block well group A is high, and the profile control and water plugging measures are to be taken. Then, pressure drawdown test is carried out and data interpretation is carried out, and the inner zone permeability is 62.4 mD, the outer zone permeability is 3.1 mD, the inner zone radius is 12.4 m, and the fracture opening is 0.049 mm. Combined with the reservoir porosity of 0.23% and the effective thickness of 5.5 m, the gel dosage (integer) is calculated as 916 m3, the particle dosage is 1 t, and the particle size range is 1-2 mm. The gel formula adopts the self-developed system of Jilin Oilfield Oil and Gas Technology Research Institute, that is, phenolic aldehyde gel IV, and the particle adopts the self-developed high-elastic expansion particle system. The designed gel+particle three-stage composite plug is used for plugging, the first plug profile control agent dosage is 183 m3 (particle size 1 mm, 0.2 t), the second plug profile control agent dosage is 274 m3 (particle size 1.5 mm, 0.3 t), and the third plug profile control agent dosage is 458 m3 (particle size 2 mm, 0.5 t). By the end of 2023, the average injection pressure rises by 0.7 MPa, the average well group liquid production decreases by 20 t, the water cut decreases by 0.3%, and the average oil production increases by 0.7 t, and good application effect is obtained.

[0092] Example 2:

[0093] As Figure 6 shown, the water cut of the effective oil well around the block well group A is high, and the profile control and water plugging measures are to be taken. Then, pressure drawdown test is carried out and data interpretation is carried out, and the inner zone permeability is 62.4 mD, the outer zone permeability is 3.1 mD, the inner zone radius is 12.4 m, and the fracture opening is 0.049 mm. Combined with the reservoir porosity of 0.23% and the effective thickness of 5.5 m, the gel dosage (integer) is calculated as 916 m3, the particle dosage is 1 t, and the particle size range is 1-2 mm. The gel formula adopts the self-developed system of Jilin Oilfield Oil and Gas Technology Research Institute, that is, phenolic aldehyde gel IV, and the particle adopts the self-developed high-elastic expansion particle system. The designed gel+particle three-stage composite plug is used for plugging, the first plug profile control agent dosage is 183 m3 (particle size 1 mm, 0.2 t), the second plug profile control agent dosage is 274 m3 (particle size 1.5 mm, 0.3 t), and the third plug profile control agent dosage is 458 m3 (particle size 2 mm, 0.5 t). By the end of 2023, the average injection pressure rises by 0.7 MPa, the average well group liquid production decreases by 20 t, the water cut decreases by 0.3%, and the average oil production increases by 0.7 t, and good application effect is obtained.

[0094] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for profile control design suitable for horizontal fractured reservoirs, characterized in that, It comprises the following steps: S1. Interpret the formation parameters such as inner and outer zone permeability, inner zone radius and formation coefficient according to the pressure drop test data of profile control well, and establish a mathematical model based on the interpreted parameters, calculate the fracture opening data, and realize the accuracy of profile control parameter calculation; S2. Optimize and select the profile control agent system and slug combination mode, select the gel and water-absorbing and swelling particle system with high plugging strength, and adopt the self-developed phenolic gel IV system; S3. Design the injection rate matching the profile control agent properties and the suitable injection pressure variation range; S4. Realize the profile control design technical idea suitable for horizontal fractured reservoir based on the profile control process parameter optimization method.

2. The method for profile control design suitable for horizontal fractured reservoirs according to claim 1, characterized in that, The horizontal fractured reservoir profile control parameter optimization method comprises the following steps: S11. Interpret the pressure drop data by well testing, obtain the inner zone permeability, outer zone permeability and inner zone radius by using the double-zone composite seepage model, and obtain the data.

3. The method for profile control design suitable for horizontal fractured reservoirs according to claim 2, characterized in that, The horizontal fractured reservoir profile control parameter optimization method further comprises the following steps: S12. Determine the plugging range based on the variation rate of pressure gradient in the near wellbore zone, and calculate the required amount of profile control agent by using the volume method.

4. The method for profile control design suitable for horizontal fractured reservoirs according to claim 3, characterized in that, The horizontal fractured reservoir profile control parameter optimization method further comprises the following steps: S13. Establish the mathematical model among the pseudo-double medium permeability, fracture opening and fracture porosity, and take the inner zone permeability obtained by well testing as the pseudo-double medium permeability and the outer zone permeability as the matrix system permeability.

5. The method for profile control design suitable for horizontal fractured reservoirs according to claim 4, characterized in that, The horizontal fractured reservoir profile control parameter optimization method further comprises the following steps: S14. The fracture opening can be calculated by using the established mathematical model.

6. The method for profile control design suitable for horizontal fractured reservoirs according to claim 5, characterized in that, The horizontal fractured reservoir profile control parameter optimization method further comprises the following steps: S15. Based on the horizontal fracture plugging design, the three-stage gel carrying particle slug is used to realize the effective plugging of the horizontal fracture.

7. The method for profile control design suitable for horizontal fractured reservoirs according to claim 6, characterized in that, The horizontal fractured reservoir profile control parameter optimization method further comprises the following steps: S16. Design the injection rate and injection pressure matching the profile control agent and the reservoir.

8. The method for profile control design suitable for horizontal fractured reservoirs according to claim 7, characterized in that, The determination of the profile control agent action range is determined according to the interwell pressure gradient data, and the pressure gradient calculation formula is as follows: In the formula: P e — Formation pressure at the boundary, MPa P wf - bottom hole flowing pressure, MPa R e — supply radius, m R w Wellbore radius, m R——distance from injection well to production well, m.

9. The method for profile control design suitable for horizontal fractured reservoirs according to claim 8, characterized in that, The profile control agent action range is determined according to the near wellbore pressure gradient variation, and the distance with the pressure gradient drop rate of more than 99% is taken as the profile control agent action range based on the pressure gradient calculation result.

10. The method for profile control design suitable for horizontal fractured reservoirs according to claim 9, wherein, The amount of the blocking agent is calculated by volume method, that is, the injected profile control agent can fill the profile control radius range, and the rubber particle density is taken as 1.25 t / m 3 The particle mass is calculated.

11. The method for profile control design suitable for horizontal fractured reservoirs according to claim 10, wherein, The fracture opening is calculated by using the chart method, the fracture opening and pseudo-double medium permeability chart is drawn by using the calculation result, the most suitable fracture opening is found, and the pseudo-double medium permeability calculation formula is as follows: In the formula: b——fracture opening, cm φ f Fracture porosity, % K m — Pseudo dual media matrix permeability, D - pseudo dual media permeability, D.

12. The method for profile control design suitable for horizontal fractured reservoirs according to claim 11, wherein, According to the previous profile control practical experience, the particle size and fracture opening matching range is established, the opening of 1-45 um corresponds to 0.2-1 mm, the opening of 45-80 um corresponds to 1-3 mm, and the opening of 80 um and above corresponds to 3-5 mm.

13. The method for profile control design suitable for horizontal fractured reservoirs according to claim 12, wherein, The three-stage slug of gel carrying particles is designed to plug the horizontal fracture, and the dosage calculation formula of each stage slug is as follows: V1 = 50% x (V g + V p ) V2 = 30% x (V g + V p ) V3 = 20% x (V g + V p ) In the formula: V1 - the third slug profile control agent dosage, m 3 V2 - second slug of profile control agent dosage, m 3 V3 - first slug profile additive dosage, m 3 .

14. The method for profile control design suitable for horizontal fractured reservoirs according to claim 13, wherein, Injection pressure design: the pressure in the construction process is less than the formation fracture pressure P 施工 <P 岩石破裂 -0.

5.

15. The method for profile control design suitable for horizontal fractured reservoirs according to claim 14, wherein, Injection rate design: different profile control agent systems adopt different injection rates: Pre-run guard (0.2% polymer) injection volume: 4mL 3 / h Gel-carrying particle system injection rate: 3 m 3 / h Post-protective solution (0.2% polymer) injection displacement: 4 m 3 / h.

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