Preparation of steam flooding oil sludge profile control agent and layer-selecting plugging control method

Abstract

The invention belongs to the technical field of petroleum, and discloses a preparation method of a steam flooding oil sludge profile control agent and a layer-selecting plugging control method. The profile control agent comprises the following raw materials: kitchen waste oil, oil sludge, calcium carbonate, calcium hydroxide, tetraethoxysilane, reed powder and sewage. The oil sludge profile control agent disclosed by the invention has good plugging performance and controllability in a high-temperature environment of 350 DEG C; the oil sludge profile control agent has strong stability in a normal temperature state, can be stored for a long time, and has good fluidity. According to the layer selection plugging control method, the purposes of layer selection plugging control and general steam injection are achieved by applying the steam injection tubular column, adopting the layer selection plugging control mode and applying the soluble ball technology, and the problem that an oil layer is not evenly used in the longitudinal direction is solved.

Description

Technical Field

[0001] The invention belongs to the field of petroleum technology and relates to a method for preparing a steam-driven oil mud profile control agent and a layer selection and plugging control method. Background Art

[0002] At present, the middle and late stages of steam drive reservoirs have entered the denudation stage. Large channels are formed under the scouring of long-term steam, resulting in serious steam channeling problems and uneven vertical utilization.

[0003] The temperature resistance of traditional sludge profile control systems is unlikely to exceed 150°C.

[0004] Traditional oil sludge profile control methods cause certain pollution to some oil layers.

[0005] Therefore, it is necessary to develop a new sludge profile control agent and layer selection injection process technology to meet the technical needs of steam drive and channeling. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing a steam flooding oil mud profile control agent and selecting and plugging layers, thereby solving the existing problems of serious steam channeling and uneven vertical utilization.

[0007] One object of the present invention is to provide a steam flooding oil sludge profile control agent, which can effectively block the high permeability layer, effectively improve the vertical utilization of steam in the oil layer while treating the oil sludge. At the same time, the main raw material is industrial production waste, which not only reduces the production cost but also protects the environment.

[0008] Another object of the present invention is to provide a method for preparing the steam flooding oil mud profile control agent.

[0009] Another object of the present invention is to provide a method for steam flooding oil mud profile adjustment, layer selection and plugging control.

[0010] The above object of the present invention is achieved through the following technical solutions:

[0011] A steam flooding oil sludge profile control agent, the raw materials of which include the following components: waste kitchen grease, oil sludge, calcium carbonate, calcium hydroxide, ethyl orthosilicate, reed powder and sewage.

[0012] The calcium carbonate, calcium hydroxide and tetraethyl orthosilicate are all commercially available conventional reagents, and any commercially available reagents meeting the corresponding quality standards can be used in the present invention and achieve the purpose of the present invention.

[0013] The waste cooking oil material is the air-dried oil remaining after catering.

[0014] The reed powder is a fine powder obtained by grinding reeds after air-drying.

[0015] The oil sludge mentioned is the oil sludge discharged from the oil field joint station.

[0016] The sewage mentioned here is sewage discharged from the oil field joint station.

[0017] The raw material composition of the profile control agent is calculated as follows in terms of mass percentage:

[0018]

[0019] The remaining amount is combined station sewage.

[0020] The preparation method of the above-mentioned profile-controlling agent is specifically as follows:

[0021] (1) Pour the oil sludge into a high-temperature reactor and heat it to 80±1°C at a rate of 5°C / min while stirring. Continue stirring for 20 minutes, weigh clean water and calcium bicarbonate, add them to the high-temperature reactor, and continue stirring for 10 minutes.

[0022] (2) Weigh calcium hydroxide and ethyl orthosilicate, add them into a high-temperature reactor while stirring, maintain the reactor temperature at 80±1°C, and continue stirring for 10 minutes.

[0023] (3) Weigh reed powder and introduce it into a high-temperature reactor while stirring. Add it in three times, with an interval of 10 minutes between each addition. After adding, maintain the reactor temperature at 90±1°C and continue stirring for 2 hours.

[0024] (3) Add sewage and kitchen waste oil into the reactor, maintain the reactor temperature at 90±1°C and stir for 20 minutes to complete the preparation. Stop heating and wait for the reactor to cool naturally to room temperature to obtain the sludge profile control agent.

[0025] The proportion of calcium bicarbonate powder with a particle size of less than 50 μm is greater than 85%; the proportion of reed powder with a particle size of less than 52 μm is greater than 95%; and the proportion of calcium hydroxide powder with a particle size of less than 44 μm is greater than 80%.

[0026] With respect to the profile control agent prepared by the above preparation method, the present invention also provides a layer selection and plugging control method using the above profile control agent, which is suitable for steam injection wells with uneven vertical production of steam drive.

[0027] To achieve the above-mentioned purpose, the present invention provides a pipe column specially used for layer selection, plugging and steam injection, including a casing, in which a thermal insulation pipe, a telescopic pipe, a hydraulic packer a, an oil pipe, a directional injection valve, a hydraulic packer b, a constant pressure ball seat, a screen pipe and a ball collector are arranged in sequence from top to bottom.

[0028] In order to further realize stratified profile control and general steam injection, the reversing ball equipped with the directional injection valve is a soluble ball.

[0029] Furthermore, the hydraulic packer a is a Y441 packer, and the hydraulic packer b is a Y341 packer. The oil pipe is a Φ73 mm oil pipe; and the screen pipe is a Φ73 mm screen pipe.

[0030] The soluble ball is a concentric ball with a copper core inside to ensure the weight of the ball and a high-temperature degradable material commonly found on the market on the outside. When high-temperature steam is injected, the soluble material degrades and the copper ball automatically falls into the ball collector, thus meeting the general steam injection requirements.

[0031] The layer selection and plugging control method of the profile control agent specifically includes: injecting oil sludge into the oil layer A and the oil layer B;

[0032] The injection of reservoir A includes

[0033] Step N1. The pipe string is lowered into the target oil layer in sequence, the top hydraulic packer a is located above the unknown oil layer A, and the interlayer hydraulic packer b is located between the unknown oil layer A and the unknown oil layer N. At this time, the top hydraulic packer a and the interlayer hydraulic packer b are in an unsealed state, and the ball of the constant pressure ball seat is not knocked off;

[0034] Step N2. After the tubing is lowered, the hydraulic packer a and the hydraulic packer b are sealed by step-by-step pressure of 1, 3, 5, 7, 10, 12, 15, and 18 MPa from the oil pipe at the wellhead. The pressure is continuously increased to 21 MPa, and the pressure-regulating ball seat is opened to release the pressure. At this time, the tubing is connected to the oil layer B.

[0035] Step N3. Put a soluble ball into the wellhead to open the upper channel of the directional injection valve.

[0036] Step N4: injecting oil sludge profile control agent into the oil layer A.

[0037] Step N4. Start injecting into oil layer A for a period of time. The hot steam further solidifies the effect of the agent, and the external material of the soluble ball is degraded. The ball falls into the ball collector along the channel. At this time, the injection of oil sludge into oil layer 1 is completed, and general steam injection is achieved at the same time.

[0038] The injection of reservoir B includes

[0039] Step S1. The pipe string is sequentially lowered into the target oil layer, the top hydraulic packer a is located above the unknown oil layer A, and the interlayer hydraulic packer b is located between the unknown oil layer A and the unknown oil layer N. At this time, the top hydraulic packer a and the interlayer hydraulic packer b are in an unsealed state, and the ball of the constant pressure ball seat is not knocked off;

[0040] Step S2. After the tubing is lowered, the hydraulic packer a and the hydraulic packer b are sealed by step-by-step pressure of 1, 3, 5, 7, 10, 12, 15, and 18 MPa from the oil pipe at the wellhead, and the pressure is continuously increased to 21 MPa. The pressure-regulating ball seat is opened and the pressure is released. At this time, the tubing is in a state of connection with the oil layer B.

[0041] Step S3: injecting oil sludge profile control agent into the oil layer B.

[0042] Step S4: Add soluble balls to ensure that the channel corresponding to oil layer A is open.

[0043] Step S5. Start injecting into the oil layer A for a period of time, the external material of the soluble ball degrades, and the ball falls into the ball receiver along the channel. At this time, the injection of the oil sludge into the oil layer B is completed, and the general steam injection is achieved at the same time.

[0044] After a period of time, the hot steam further solidifies the agent effect, the external material of the soluble ball is degraded, and the ball falls into the ball collector along the channel. At this time, the injection of the oil sludge in the oil layer A is completed, and the general steam injection is realized at the same time.

[0045] The beneficial effects of the present invention compared with the prior art are:

[0046] The profile controlling agent provided by the present invention comprises calcium bicarbonate, calcium hydroxide, ethyl orthosilicate and oil sludge, which effectively realizes the consolidation effect and the plugging effect of the oil-containing sludge profile controlling agent in a high temperature environment; the addition of waste kitchen grease can effectively improve the suspension and dispersion of each component in the oil-containing sludge profile controlling agent, and prevent consolidation at room temperature; the reed powder has a high silicon content and a high fiber content, and can improve the stability of the agent under high temperature conditions, thereby ensuring long-term effectiveness after solidification.

[0047] On the one hand, the profile control agent provided by the present invention mainly starts from reducing production costs, using the remaining oil after catering and the oil sludge and sewage from the joint station as raw materials, solving the problem of the high price of the plugging control agent. At the same time, according to the production characteristics of steam drive in Liaohe Oilfield, the high temperature resistance effect of the profile control agent of the present invention is evaluated through indoor experiments, and it has a strong consolidation effect on the oil sludge under high temperature conditions, and has excellent performance.

[0048] In order to realize the selective layer injection of oil sludge profile control agents, the present invention provides a steam injection pipe column on the one hand and a selective layer plugging control method on the other hand. A layered injection device is used to inject the profile control agent into the high permeability layer, and then general steam injection is implemented, ultimately achieving the purpose of selective layer plugging control and general steam injection, effectively blocking the high permeability layer channel, and ensuring that the injected steam enters the low permeability layer.

[0049] The oil sludge profile control agent of the present invention has good plugging performance and controllability in a high temperature environment of 350°C; it has strong stability and can be stored for a long time at room temperature, and the oil sludge profile control agent has good fluidity. The selective layer plugging method uses a steam injection column, adopts a selective layer plugging method, and uses soluble ball technology to achieve the purpose of selective layer plugging and general steam injection, thereby solving the problem of uneven vertical utilization of the oil layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1It is a structural diagram specially used for layer selection, blockage and steam injection pipe column.

[0051] Figure 2 It is a schematic diagram of the structure of a soluble sphere.

[0052] Figure 3 This is a comparison curve of the pressure before and after steam injection after the injection of a 40-block-18-KN oil sludge profile control agent.

[0053] In the figure: 1. oil layer A, 2. interlayer, 3. oil layer B, 4. Φ114 insulation pipe, 5. telescopic pipe, 6. hydraulic packer a, 7. oil pipe, 8. directional injection valve, 9. constant pressure ball seat, 10. screen pipe, 11. ball collector, 12. casing, 13. hydraulic packer b. DETAILED DESCRIPTION

[0054] The present invention is described in detail below by specific examples, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0055] Example 1

[0056] According to a specific embodiment of the present invention, in the profile-controlling agent of the present invention, each raw material component is calculated as a percentage by mass unit:

[0057]

[0058] The remaining amount is the sewage from the joint station

[0059] (1) Pour the oil sludge into a high-temperature reactor and heat it to 80±1°C at a rate of 5°C / min while stirring. Continue stirring for 20 minutes, weigh clean water and calcium bicarbonate, add them to the high-temperature reactor, and continue stirring for 10 minutes.

[0060] (2) Weigh calcium hydroxide and ethyl orthosilicate, add them into a high-temperature reactor while stirring, maintain the reactor temperature at 80±1°C, and continue stirring for 10 minutes.

[0061] (3) Weigh reed powder and introduce it into a high-temperature reactor while stirring. Add it in three times, with an interval of 10 minutes between each addition. After adding, maintain the reactor temperature at 90±1°C and continue stirring for 2 hours.

[0062] (3) Add sewage and kitchen waste oil into the reactor, maintain the reactor temperature at 90±1°C and stir for 20 minutes to complete the preparation, stop heating, and wait for the reactor to cool naturally to room temperature to obtain the sludge profile control agent.

[0063] The profile-control agent prepared in Example 1 was studied and tested in terms of solidification time, agent fluidity, temperature resistance, aging resistance, and temperature resistance.

[0064] (1) Curing reaction time

[0065] In order to verify the curing effect of the oil sludge profile control agent under high temperature, a curing time test experiment was carried out. The experimental results are shown in Table 1; from the experiment in Table 1, it can be concluded that the curing reaction time of the oil sludge profile control agent is controllable within 14.3 to 5.9 days.

[0066] Table 1: Curing time of sludge profile control agent at 150℃-350℃

[0067]

[0068] (II) Liquidity test

[0069] Five samples of the oil sludge profile control agent provided in Example 1 were taken at room temperature (10°C-30°C) and the viscosity was tested using a rotational viscometer to reflect the fluidity of the profile control agent in this environment. The results are shown in Table 2. The experiment showed that the viscosity of the agent at room temperature was 201-276 mPa.s, ensuring safe injection.

[0070] Table 2: Viscosity of oil sludge profile control agents at room temperature

[0071] Viscosity mPa.s 10℃ 15℃ 20℃ 25℃ 30℃ Sample 1 276 261 248 229 204 Sample 2 265 259 250 231 209 Sample 3 273 254 241 227 210 Sample 4 277 258 238 228 208 Sample 5 268 251 235 221 201

[0072] (III) Aging and residual resistance coefficient test

[0073] The aging property and residual resistance coefficient of the test agent in an ultra-high temperature environment are as follows: the oil sludge profile control agent provided in Example 1 is injected into the core, and the original permeability of the core is 2.1 μm 2 (Qi 40 steam flooding average permeability), inject 1.1PV of sludge profile control agent, and put the agent into three high-temperature kettles and heat them to 200℃, 250℃, and 350℃, and measure the aging time and residual resistance coefficient under different environments. It always remains above 15, showing a good plugging effect. The higher the high-temperature kettle environment temperature, the lower the sample resistance coefficient. The experimental results are shown in Table 3.

[0074] Table 3: Aging time and residual resistance coefficient of profile control agents under different environments

[0075]

[0076] Comparative Example 1

[0077] On the premise that other components of the sludge profile control agent provided in Example 1 remain unchanged, the mass percentage of reed powder is reduced from 5% to 3% to obtain sludge profile control agent II, and its curing reaction time and temperature resistance are tested. The experimental methods are the same as those in Example 1 (1) curing reaction time and (3) aging and residual resistance coefficient experimental evaluation. The results are shown in Tables 4 and 5.

[0078] Table 4: Curing time of oil sludge profile control agent II at 150℃-350℃

[0079] Temperature / ℃ 150 170 190 210 230 250 270 290 310 330 350 Curing time 11.2 10.5 9.7 8.8 7.9 6.7 5.8 4.9 4.1 3.8 3.4

[0080] Table 5: Aging time and residual resistance coefficient of oil sludge profile control agent II under different environments

[0081]

[0082] The mass percentage of reed powder in the sludge profile control agent II was reduced from 5% to 3%, and the curing time was 3.4-11.2d. At the same time, from the data in Table 5, the residual resistance coefficient also decreased. In a high temperature environment of 350°C, the residual resistance coefficient dropped to 12.4. It can be seen that the reduction in the proportion of reed powder reduced the consolidation effect.

[0083] Application Example 1

[0084] Oil sludge profile control injection was implemented in a 40-block-18-KN steam injection well group. The well had the problem of uneven oil layer utilization. Through well temperature testing and oil layer interpretation, it was found that the upper part showed steam inrush, and the average permeability of the upper part was 3.2μm2, and the average permeability of the lower part was 1.5μm2. Therefore, oil sludge and sewage were injected into the upper layer, and then general steam injection was implemented.

[0085] The specific implementation steps are as follows:

[0086] Step N1. The pipe string is lowered into the target oil layer in sequence, the top hydraulic packer a is located on the upper part of the unknown oil layer A, and the interlayer hydraulic packer b is located between the unknown oil layer 1 and the unknown oil layer N. At this time, the top hydraulic packer a and the interlayer hydraulic packer b are in an unsealed state, and the ball of the constant pressure ball seat is not knocked off;

[0087] Step N2. After the tubing is lowered, the hydraulic packer a and the hydraulic packer b are sealed by step-by-step pressure of 1, 3, 5, 7, 10, 12, 15, and 18 MPa from the oil pipe at the wellhead. The pressure is continuously increased to 21 MPa, and the pressure-regulating ball seat is opened to release the pressure. At this time, the tubing is connected to the oil layer B.

[0088] Step N3. The raw material components of the oil sludge profile control agent are calculated as percentage by mass:

[0089]

[0090] The remaining amount is the sewage from the joint station

[0091] Prepare the oil sludge profile control agent according to the preparation requirements.

[0092] Step N4: injecting sludge profile control agent into the oil layer B.

[0093] Step N4. Add soluble balls to ensure that the corresponding channel of oil layer A is open.

[0094] Step N5. Start injecting into oil layer A for a period of time, the external material of the soluble ball degrades, and the ball falls into the ball receiver along the channel. At this time, the injection of oil sludge into oil layer B is completed, and general steam injection is achieved at the same time.

[0095] After a period of time, the hot steam further solidifies the agent effect, the external material of the soluble ball is degraded, and the ball falls into the ball collector along the channel. At this time, the injection of oil sludge in oil layer 1 is completed, and general steam injection is achieved at the same time.

[0096] After the above method was applied to the injection of oil mud profile control agent in a steam injection well of a certain 40-18-KN well group, the average steam injection pressure increased from 4.5MPa to 6.3MPa in the month before the measure, and increased by 1MPa in the stable period, while the steam injection volume remained unchanged. It has a certain effect on the vertical production of the oil layer. See the effect diagram Figure 3 .

[0097] The above-described embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A steam flooding sludge profile control agent, characterized in that: The raw materials of profile control agents include the following ingredients: waste cooking oil, oil sludge, calcium carbonate, calcium hydroxide, ethyl orthosilicate, reed powder, and sewage.

2. A steam flooding oil mud profile control agent as claimed in claim 1, characterized in that: The waste cooking oil material is the grease left over from catering that has been air-dried; The reed powder is a fine powder made by grinding reeds after air drying; The oil sludge mentioned is the oil sludge discharged from the oil field joint station; The sewage mentioned here is sewage discharged from the oil field joint station.

3. A steam flooding oil mud profile control agent as claimed in claim 2, characterized in that: The raw material composition of the profile control agent is calculated as follows in terms of mass percentage: The remaining amount is combined station sewage.

4. The method for preparing the steam flooding oil mud profile control agent according to claim 3, characterized in that: The details are as follows: (1) Pour the sludge into a high-temperature reactor, heat it to 80±1°C at a rate of 5°C / min while stirring, continue stirring for 20 minutes, weigh clean water and calcium bicarbonate, add them to the high-temperature reactor, and continue stirring for 10 minutes; (2) Weigh calcium hydroxide and ethyl orthosilicate, add them into a high-temperature reactor while stirring, maintain the reactor temperature at 80±1°C, and continue stirring for 10 minutes; (3) Weigh reed powder and introduce it into a high-temperature reactor while stirring. Add it three times, with an interval of 10 minutes between each addition. After adding, keep the reactor temperature at 90±1°C and continue stirring for 2 hours; (3) Add sewage and kitchen waste oil into the reactor, maintain the reactor temperature at 90±1°C and stir for 20 minutes to complete the preparation. Stop heating and wait for the reactor to cool naturally to room temperature to obtain the sludge profile control agent.

5. The preparation method according to claim 4, characterized in that: The proportion of the calcium bicarbonate powder with a particle size less than 50 μm is greater than 85%; the proportion of the reed powder with a particle size less than 52 μm is greater than 95%; and the proportion of the calcium hydroxide powder with a particle size less than 44 μm is greater than 80%.

6. A layer selection and plugging control method for a profile control agent prepared by the preparation method according to any one of claims 4 to 5, characterized in that: Used for steam injection wells with uneven vertical utilization of steam drive.

7. The layer selection and plugging method according to claim 6, characterized in that: A pipe string specially used for layer selection, plugging and steam injection is selected, including casing. Insulation pipe, telescopic pipe, hydraulic packer a, oil pipe, directional injection valve, hydraulic packer b, constant pressure ball seat, screen pipe and ball collector are arranged in sequence from top to bottom in the casing; the reversing ball equipped with the directional injection valve is a soluble ball.

8. The layer selection and plugging method according to claim 7 is characterized in that: include: Select oil layers A and B to inject oil sludge; The injection of reservoir A includes Step N1. The pipe string is lowered into the target oil layer in sequence, the top hydraulic packer a is located above the unknown oil layer A, and the interlayer hydraulic packer b is located between the unknown oil layer A and the unknown oil layer N. At this time, the top hydraulic packer a and the interlayer hydraulic packer b are in an unsealed state, and the ball of the constant pressure ball seat is not knocked off; Step N2. After the string is lowered, the hydraulic packer a and the hydraulic packer b are set at 1, 3, 5, 7, 10, 12, 15, and 18 MPa from the oil pipe at the wellhead step by step, and the pressure is continuously raised to 21 MPa. The pressure-regulating ball seat is opened and the pressure is released. At this time, the string is in a state of connection with the oil layer B; Step N3. Place a soluble ball at the wellhead and open the upper channel of the directional injection valve; Step N4. Injecting a sludge profile control agent into the oil layer A; Step N4. Start injecting into the oil layer A for a period of time, the hot steam further solidifies the effect of the agent, the external material of the soluble ball is degraded, and the ball falls into the ball collector along the channel. At this time, the injection of the oil sludge in the oil layer 1 is completed, and the general steam injection is achieved at the same time; The injection of reservoir B includes Step S1. The pipe string is sequentially lowered into the target oil layer, the top hydraulic packer a is located above the unknown oil layer A, and the interlayer hydraulic packer b is located between the unknown oil layer A and the unknown oil layer N. At this time, the top hydraulic packer a and the interlayer hydraulic packer b are in an unsealed state, and the ball of the constant pressure ball seat is not knocked off; Step S2. After the tubing is lowered, the hydraulic packer a and the hydraulic packer b are sealed by step-by-step pressure of 1, 3, 5, 7, 10, 12, 15, and 18 MPa from the oil pipe at the wellhead, and the pressure is continuously increased to 21 MPa. The pressure-regulating ball seat is opened and the pressure is released. At this time, the tubing is in a state of being connected to the oil layer B; Step S3. injecting oil sludge profile control agent into oil layer B; Step S4. Add soluble balls to ensure that the channel corresponding to oil layer A is open; Step S5. Start injecting into the oil layer A for a period of time, the external material of the soluble ball degrades, and the ball falls into the ball receiver along the channel. At this time, the injection of the oil sludge into the oil layer B is completed, and the general steam injection is achieved at the same time; After a period of time, the hot steam further solidifies the agent effect, the external material of the soluble ball is degraded, and the ball falls into the ball collector along the channel. At this time, the injection of the oil sludge in the oil layer A is completed, and the general steam injection is realized at the same time.

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