Method for testing and evaluating sand prevention performance of sand stabilizer

Abstract

The invention provides a sand control performance test and evaluation method for a sand stabilizer, which comprises the following steps: step 1, setting the pump flow as Q0, pumping liquid into a stratum sand filling module, and recording the sand production amount; 2, after the fluid pressure is stable, liquid pumping is stopped, and the sand production amount at the moment is recorded; 3, a sand stabilizing agent is pumped into the stratum sand filling module, and the sand stabilizing agent is waited to be solidified; 4, the pump flow is set to be Q0, liquid is pumped into the stratum sand filling module again, and the sand production amount is recorded; 5, after the fluid pressure is stable, the sand production amount is recorded; and 6, the pump flow is adjusted to Q1, the steps p4-5 are repeated till the fluid pressure is stable, and the sand production amount at the moment is recorded. The method for testing and evaluating the sand prevention performance of the sand stabilizer provides an experimental method and a data processing and evaluating method for evaluating the comprehensive sand prevention performance of the sand stabilizer, can be used for sand prevention and control process design of an oil well, and provides an efficient and long-acting sand stabilization effect.

Description

Technical Field

[0001] The invention relates to the technical field of well completion engineering of resources such as petroleum and natural gas, and in particular to a method for testing and evaluating the sand control performance of a sand stabilizer. Background Art

[0002] The oil and gas reservoirs in the eastern part of my country, such as Shengli Oilfield, Daqing Oilfield and North China Oilfield, are shallowly buried, and the sandstone strata where the oil and gas resources are located are loose in structure. During the exploitation of oil and gas wells, sand particles are easily detached from the rock skeleton and migrated out of the reservoir with the fluid. This phenomenon is called sand production. Long-term sand production will affect the production of oil and gas wells and thus reduce production efficiency. For oil and gas wells with sand production problems, injecting sand stabilizers into the reservoir is a commonly used auxiliary sand prevention process. The principle is to inject sand stabilizers into the loose sandstone reservoirs, cover the surface of the sandstone, and play a role in inhibiting and stabilizing the formation sand particles, thereby alleviating the sand production problem. At present, various oil fields have developed a variety of sand stabilizer products, but the existing sand stabilizer sand stabilization performance test methods and evaluation methods have the following problems:

[0003] (1) The existing test equipment used to evaluate the sand-control properties of sand stabilizers is relatively simple. It mainly evaluates the permeability and sand output changes of the formation sand filling module after the sand stabilizer is mixed. It cannot simulate the on-site sand stabilizer squeezing construction process. There is a large deviation between the experimental steps and the actual oil field construction methods. There is a lack of a sand stabilizer sand control performance evaluation test system under real pumping construction conditions.

[0004] (2) In the existing technology, for example, Wang Lizhi, Dong Changyin and others published "Evaluation and Parameter Optimization of Chemical Sand Consolidation and Sand Suppression Auxiliary Sand Control Experiment in Enping Oilfield". In order to solve the sand production problem in Enping heavy oil field, chemical / mechanical composite sand control is needed, and chemical assisted sand control parameters need to be optimized urgently. Using the chemical assisted sand control evaluation experimental device, phenolic resin, furan resin, epoxy resin and FYJ sand suppressant were used to consolidate the formation sand, and a composite unidirectional displacement experiment was carried out with the screen pipe slice. According to the experiment, a complete chemical assisted sand control evaluation method was established, and the comprehensive sand control performance of the chemical sand control agent was quantitatively evaluated by measuring experimental data such as flow rate, pressure difference and sand passing amount. The results show that after adding the chemical agent, the sand passing rate of the consolidated layer is reduced by 42% to 65%, and the permeability is damaged by 14% to 70%; the improvement of the sand consolidation effect will cause permeability damage, and the medium blockage will be aggravated after the sand is produced at the outer end of the consolidated layer. According to the evaluation results, low mass fraction FYJ sand suppressant is preferably used for deep formation sand stabilization and consolidation operations.

[0005] Zhao Peng, Mei Lei and others published "Development and Performance Research of Anti-swelling and Sand Inhibiting Agents for Heavy Oil Reservoirs". Swelling and sand inhibitors are core additives for heavy oil reservoirs used to prevent reservoir clay expansion and inhibit formation sand dispersion and migration. Using acrylamide and trimethylallyl ammonium chloride as raw materials, the anti-swelling and sand inhibitor products were obtained by reaction at 70°C for 4 hours. Its structure was characterized by infrared spectroscopy and thermogravimetric / differential thermal analysis, and the effects of reaction raw materials and the amount of anti-swelling and sand inhibitor on the anti-swelling effect and sand inhibition effect were investigated. The results showed that with the addition of acrylamide and trimethylallyl ammonium chloride, the anti-swelling and sand inhibitor products were The anti-swelling rate increases with the decrease of the mass ratio of propyl ammonium chloride. When the mass ratio of acrylamide to trimethylallyl ammonium chloride is 7:3, the anti-swelling rate of the anti-swelling and sand-inhibiting agent product with an addition of 0.5% is 94.90%, and the migration degree of sand particles washed out of the formation sand is 4.04% before treatment. As the amount of anti-swelling and sand-inhibiting agent increases, the anti-swelling rate increases, and the amount of anti-swelling and sand-inhibiting agent is preferably 0.5%. According to the core damage performance evaluation results, at temperatures of 30℃ and 120℃, the damage rate of the anti-swelling and sand-inhibiting agent to the core permeability is small, both less than 10%.

[0006] Zhang Sen, Tian Chengcun et al. published "Synthesis and Performance Evaluation of Cationic Polymer Anti-swelling and Sand-inhibiting Agents". Two cationic polymer anti-swelling and sand-inhibiting agents were synthesized, their anti-swelling and sand-inhibiting properties were evaluated, and compared with some anti-swelling and sand-inhibiting agents commonly used in oil fields. The results showed that the products had good anti-swelling and sand-inhibiting properties. The effects of quartz sand particle size and driving medium viscosity on product performance were studied. The results showed that when the quartz sand particle size was greater than 0.3 mm and the driving medium viscosity was greater than 50 mPa*s, the synthesized product basically lost its sand-inhibiting ability.

[0007] In the Chinese patent application with application number: CN201910986668.0, a multi-stage stable and long-term sand control process method for sandstone reservoirs with high water content in the late stage is involved. The multi-stage stable and long-term sand control process method for sandstone reservoirs with high water content in the late stage includes: step 1, establishing a reservoir instability model and a method for distinguishing the degree of instability; step 2, preventing reservoir instability based on real-time regulation of fluid flow rate; step 3, performing in-situ stabilization and skeleton reconstruction of the reservoir by physical and chemical coupling of high-efficiency chemicals; step 4, reconstructing the high-strength and high-permeability artificial well wall of the reservoir near the wellbore collapse; step 5, performing sand control by the filter sand pipe for high seepage prevention and blockage of the wellbore; step 6, performing reservoir seepage capacity recovery treatment. The multi-stage stable and long-term sand control process method for sandstone reservoirs with high water content in the late stage effectively reduces the destruction of the skeleton sand and the degree of sand production of the reservoir in the high water content period, eliminates the near-wellbore blockage of the reservoir after water flooding and polymer flooding, improves the liquid volume level, and realizes the efficient development of loose sandstone reservoirs in the oil field.

[0008] In the Chinese patent application with application number: CN202111146406.7, a sand stabilizer and its preparation method are involved. The sand stabilizer of the invention is mainly composed of water, thickener, amino resin and anti-swelling agent; wherein, the weight ratio of thickener, amino resin and anti-swelling agent is (0.015-0.03): (0.02-0.05): (0.02-0.05). In the sand stabilizer of the invention, the thickener can increase the viscosity of the solution, increase the consistency, increase the resistance to particle migration, extend the time for free matter to migrate to the near-wellbore area, and increase the effective period of sand control. The amino group in the amino resin can be bridged with the hydroxyl group on the surface of the loose sand particles through hydrogen bonds to achieve the purpose of sand control. In addition, the amino resin can enhance the viscosity of formation clay minerals, quartz, etc., so that the mineral particles are linked and agglomerated, and are not easily entrained and transported by the fluid, which increases the difficulty of particle movement. The anti-swelling agent forms a protective film on the surface of clay minerals and free sand particles, coating and inhibiting the hydration and dispersion of clay minerals and free sand particles.

[0009] The above existing technologies are quite different from the present invention. Most of the screening methods are qualitative evaluation experiments. The evaluation factors considered are mainly the sand production and permeability under single flow conditions. There is a lack of comprehensive quantitative evaluation methods for the scouring resistance of sand stabilizers under variable flow conditions. The applicability of different sand stabilizers to target oil wells is unclear, and there is a lack of evaluation methods for conveniently and quickly selecting highly adaptable sand stabilizers on the oil field site. The technical problems we wanted to solve were not solved, so we invented a new sand stabilizer sand control performance test and evaluation method. Summary of the invention

[0010] The purpose of the present invention is to provide a sand control performance testing and evaluation method for a sand stabilizing agent that can be used in a sand control process design for an oil well and provides an efficient and long-lasting sand stabilizing effect.

[0011] The purpose of the present invention can be achieved by the following technical measures: a sand stabilizer sand control performance testing method and an evaluation method, the sand stabilizer sand control performance testing and evaluation method comprising:

[0012] Step 1, set the pump flow rate to Q0, pump liquid into the formation sand filling module, and record the sand output;

[0013] Step 2: After the fluid pressure is stable, stop pumping the liquid and record the amount of sand produced at this time;

[0014] Step 3, pumping a sand stabilizer into the formation sand filling module and waiting for the sand stabilizer to solidify;

[0015] Step 4, set the pump flow rate to Q0, pump liquid into the formation sand filling module again, and record the sand output;

[0016] Step 5, after the fluid pressure is stable, record the amount of sand produced;

[0017] Step 6: Adjust the pump flow rate to Q1 and repeat steps p4-5 until the fluid pressure stabilizes, and record the sand output at this time.

[0018] The purpose of the present invention can also be achieved by the following technical measures:

[0019] The sand stabilizer sand control performance testing and evaluation method also includes, before step 1, weighing the formation sand filling module and then connecting it to the experimental system.

[0020] In step 1, the pump flow rate Q0 is set and the liquid pump is started to pump liquid into the formation sand filling module, and the sand output of the formation sand filling module is recorded at every time step Δt.

[0021] In step 2, after the fluid pressure of the formation sand filling module stabilizes at time T0, stop pumping liquid into the formation sand filling module, and record the sand output of the formation sand filling module at this time, and record the pressure at the inlet and outlet of the formation sand filling module in real time, and calculate the total pressure drop from the outlet to the inlet of the formation sand filling module.

[0022] In step 4, the pump flow rate Q0 is set and the liquid pump is started to pump liquid into the formation sand filling module. The sand output of the formation sand filling module is recorded at each time step Δt, and the pressure at the inlet and outlet of the formation sand filling module is recorded in real time.

[0023] In step 5, after the fluid pressure of the formation sand filling module is stabilized at time T1, the sand output of the formation sand filling module at this time is recorded.

[0024] In step 6, adjust the pump flow to Q1 and repeat steps 4-5 until the pump flow is adjusted to Q i , and at T i After the fluid pressure of the formation sand filling module is stable, record the sand output of the formation sand filling module at this time

[0025] The sand stabilizing agent sand control performance testing and evaluation method further includes, after step 6, step 7, stopping pumping liquid into the formation sand filling module.

[0026] The sand control performance testing and evaluation method of the sand stabilizer also includes, after step 7, step 8, calculating the sand stabilization performance index, the flow performance index, the comprehensive sand control performance index and the minimum treatment radius.

[0027] In step 8, the sand stabilization performance index calculation formula is:

[0028]

[0029] In formula (1), C m —Sand stabilization performance index; v0——Sand production speed after pumping sand stabilizer, sand production after pumping sand stabilizer The slope of the fitting curve with time is obtained, g / s; v′0——sand production velocity before pumping sand stabilizer, and the sand production before pumping sand stabilizer The slope of the fitting curve with time, g / s, was obtained by the above test method.

[0030] In step 8, the flow performance index calculation formula is:

[0031]

[0032] In formula (2), C k —Flow performance index; k0——core permeability after pumping sand stabilizer, calculated by Darcy formula, μm 2 ; k'0——core permeability before pumping sand stabilizer, calculated by Darcy's formula, μm 2 .

[0033] In step 8, the calculation formula for the erosion resistance performance index is:

[0034]

[0035] In formula (3), C q —Erosion resistance performance index; q——Erosion resistance flow rate of sand stabilizer, that is, the flow rate after pumping sand stabilizer under the same sand production speed as when the flow rate before pumping sand stabilizer is q0, mL / min, measured by the above test method; q0——The flow rate before pumping sand stabilizer, the experiment is generally set to 100mL / min.

[0036] In step 8, the comprehensive sand control performance index calculation formula is:

[0037] C ssp =f m C m +f k C k +f q C q (4)

[0038] f m +f k +f q =1 (5)

[0039] In formula (4) and (5), C ssp It is the comprehensive performance index of sand stabilizer; m is the weight coefficient of sand stabilization performance; f k is the flow performance weight coefficient; f q is the weight coefficient of erosion resistance performance. m C is the sand stabilization performance index; k Is the flow performance index; C qIt is an indicator of erosion resistance performance.

[0040] In step 8, if the oilfield production focuses on optimizing and ensuring that the target oil well does not produce sand in the near future, the weight coefficients of sand stabilization performance, flow performance, and erosion resistance performance are 0.5, 0.3, and 0.2 respectively;

[0041] If the oil field production focuses on prioritizing the high production of the target oil wells in the near term, the weight coefficients of sand stabilization performance, flow performance, and erosion resistance performance are 0.2, 0.5, and 0.3, respectively.

[0042] In step 8, the calculation method of the minimum treatment radius of the sand stabilizing agent at the oil field site is:

[0043] If the erosion resistance performance index of the sand stabilizer is C q <1.5, the sand stabilizer is considered substandard and is not recommended for use; if the erosion resistance index C q ≥1.5, it means that the sand stabilizer has practical applicability and can be used. Then, the minimum treatment radius is calculated based on the erosion resistance flow rate q of the sand stabilizer measured by its test method. The method is as follows:

[0044] The formation flow distribution curve is shown in formula (6):

[0045]

[0046] In formula (6): Q N - formation flow rate, mL / min; h—effective reservoir thickness, m; φ—reservoir porosity, %; K h —Average formation permeability, μm 2 ; μ—fluid viscosity, using the actual viscosity of the displacement fluid used in the experiment, MPa·s; P e —formation pressure, MPa; P w —Bottomhole flowing pressure, MPa; R w —Wellbore radius, m; R e —formation oil supply radius, m; R—formation radius, m;

[0047] Input parameters h, φ, K h ,μ,P e , P, R w , R e After that, the horizontal flow distribution curve of the bottom formation of the production well can be obtained;

[0048] Using this flow distribution curve, let Q N =q, we can get the formation radius R corresponding to the erosion resistance flow rate q of the sand stabilizer. The formation radius R is the minimum treatment radius Rc of the sand stabilizer, in m.

[0049] The sand control performance testing and evaluation method of the sand stabilizer in the present invention, through experimental simulation of the construction procedures of sand stabilizer pumping, well closing and waiting for solidification, and well opening with variable flow production, can restore the real sand control performance of the sand stabilizer in the actual construction environment to a greater extent. The comprehensive sand prevention and control effect of the sand stabilizer is evaluated by testing the dynamic data such as displacement flow, displacement pressure difference, and sand output before and after the sand stabilizer is pumped; comprehensive quantitative evaluation indicators and evaluation methods such as sand stabilization performance, flow performance, and scour resistance performance of the sand stabilizer are constructed to compare different sand stabilizers; the scour resistance flow rate is obtained through the specified scour resistance performance index, thereby obtaining the applicable treatment radius range of the sand stabilizer. The experimental method, data processing and evaluation method provided for the evaluation of the comprehensive sand control performance of the sand stabilizer can be used in the sand prevention and control process design of oil wells, and provide efficient and long-lasting sand stabilization effects. Compared with the prior art, the present invention has the following advantages:

[0050] (1) The sand control performance testing method of the sand stabilizer provided by the present invention takes into account the construction procedures of simulating sand stabilizer pumping, shutting in the well to wait for solidification, and opening the well for variable flow production, and can restore the real sand control performance of the sand stabilizer in the actual construction environment to a greater extent.

[0051] (2) The present invention provides sand stabilization performance, flow performance and scour resistance performance indicators of sand stabilizers to compare different sand stabilizers, and the evaluation method is scientific and reasonable; the sand stabilization performance indicator takes into account the basic control ability of the sand stabilizer on the exfoliation and migration of formation sand particles; the flow performance indicator takes into account the degree of damage of the sand stabilizer to the permeability of the reservoir; the scour resistance performance indicator takes into account the adhesion ability of the sand stabilizer to sandstone under the action of formation fluid dynamics; the evaluation is objective and reasonable. Quantitative evaluation indicators can be calculated by specific calculation methods, which is convenient for horizontal comparative evaluation of multiple sand stabilizers. This evaluation index system and its calculation method are particularly useful for experimental tests aimed at optimizing the type of sand stabilizer.

[0052] (3) The present invention provides a comprehensive sand control performance quantitative evaluation method. According to the production requirements of different oil fields, the sand stabilization performance, flow performance and scour resistance of the sand stabilizer are flexibly considered to meet the requirements of the target oil well, thereby improving the rationality of the chemical sand control design parameters and improving the sand control effect. The idea of ​​obtaining the minimum treatment radius of the sand stabilizer provided by the present invention is operational and can be used for convenient and quick chemical sand control design at the oil field site. It is expected to improve the design efficiency of sand control engineers at the oil field site by 60%, and has direct guiding value for the optimization design of chemical sand control construction parameters and pumping procedures. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the structure of an experimental device in an embodiment of the present invention;

[0054] Figure 2 It is a fitting relationship curve diagram of the sand production and displacement time at the flow rate Qi in the embodiment of the present invention;

[0055] Figure 3 It is a flow chart of a specific embodiment of the method for testing and evaluating the sand control performance of the sand stabilizer of the present invention;

[0056] In the figure, there are a liquid storage tank 1, a horizontal flow pump liquid supply module 2, a formation sand filling module 3, a sand-liquid separation and collection module 4, a waste liquid collection container 5, an intermediate container module 6, a front pressure sensor 7, a flow sensor 8, a rear pressure sensor 9, and a data acquisition system module 10. DETAILED DESCRIPTION

[0057] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0058] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0059] The sand stabilizing agent sand control performance testing and evaluation method of the present invention comprises:

[0060] Step 1, set the pump flow rate to Q0, pump liquid into the formation sand filling module, and record the sand output;

[0061] Step 2: After the fluid pressure is stable, stop pumping the liquid and record the amount of sand produced at this time;

[0062] Step 3, pumping a sand stabilizer into the formation sand filling module and waiting for the sand stabilizer to solidify;

[0063] Step 4, set the pump flow rate to Q0, pump liquid into the formation sand filling module again, and record the sand output;

[0064] Step 5, after the fluid pressure is stable, record the amount of sand produced;

[0065] Step 6: Adjust the pump flow rate to Q1 and repeat steps p4-5 until the fluid pressure stabilizes, and record the sand output at this time.

[0066] Step 7, stop pumping liquid into the formation sand filling module.

[0067] Step 8, calculate the sand stabilization performance index, flow performance index, comprehensive sand control performance index and minimum treatment radius.

[0068] The following are several specific embodiments of the present invention.

[0069] Example 1

[0070] In a specific embodiment 1 of the present invention, Figure 3 As shown, Figure 3 The flowchart of the sand stabilizer sand control performance test and evaluation method of the present invention comprises:

[0071] Step 101, weighing the formation sand filling module and connecting it to the experimental system;

[0072] Step 102, setting the pump flow rate Q0 and starting the liquid pump to pump liquid into the formation sand filling module, and recording the sand output of the formation sand filling module at every time step Δt;

[0073] Step 103, after the fluid pressure of the formation sand filling module is stable at time T0, stop pumping liquid into the formation sand filling module, record the sand output of the formation sand filling module at this time, record the pressure at the inlet and outlet of the formation sand filling module in real time, and calculate the total pressure drop from the outlet to the inlet of the formation sand filling module;

[0074] Step 104, pumping a sand stabilizer into the formation sand filling module and waiting for the sand stabilizer to solidify;

[0075] Step 105, setting the pump flow rate Q0 and starting the liquid pump to pump liquid into the formation sand filling module, recording the sand output of the formation sand filling module at every time step Δt, and recording the pressure at the inlet and outlet of the formation sand filling module in real time;

[0076] Step 106, after the fluid pressure of the formation sand filling module is stabilized at time T1, the sand output of the formation sand filling module at this time is recorded;

[0077] Step 107, adjust the pump flow to Q1 and repeat steps 5-6 until the pump flow is adjusted to Q i , and at T i After the fluid pressure of the formation sand filling module is stable, record the sand output of the formation sand filling module at this time

[0078] Step 108, stop pumping liquid into the formation sand filling module.

[0079] During the experiment, the data automatically tested and collected according to the set time step Δt include: Q i —Liquid flow rate after the ith adjustment, m 3 / s; ΔP i —The total pressure drop from the outlet to the inlet of the formation sand filling module after the i-th flow adjustment, MPa; the data tested manually include: T i—Displacement time corresponding to the i-th flow adjustment, s; —The amount of sand produced at the kth measurement after the ith flow adjustment, g.

[0080] Example 2

[0081] In a specific embodiment 2 of the present invention, the sand stabilizing agent sand control performance testing and evaluation method includes the following steps:

[0082] Step 1, weigh the formation sand filling module and connect it to the experimental system;

[0083] Step 2, set the pump flow rate Q0 and start the liquid pump to pump liquid into the formation sand filling module, and record the sand output of the formation sand filling module at every time step Δt;

[0084] Step 3, after the fluid pressure of the formation sand filling module is stable at time T0, stop pumping liquid into the formation sand filling module, and record the sand output of the formation sand filling module at this time, and record the pressure at the inlet and outlet of the formation sand filling module in real time, and calculate the total pressure drop from the outlet to the inlet of the formation sand filling module;

[0085] Step 4, pumping sand stabilizer into the formation sand filling module and waiting for the sand stabilizer to solidify;

[0086] Step 5, set the pump flow rate Q0 and start the liquid pump to pump liquid into the formation sand filling module, record the sand output of the formation sand filling module at every time step Δt, and record the pressure at the inlet and outlet of the formation sand filling module in real time;

[0087] Step 6, after the fluid pressure of the formation sand filling module is stable at time T1, the sand output of the formation sand filling module is recorded;

[0088] Step 7, adjust the pump flow to Q1 and repeat steps 5-6 until the pump flow is adjusted to Q i , and at T i After the fluid pressure of the formation sand filling module is stable, record the sand output of the formation sand filling module at this time

[0089] Step 8, stop pumping liquid into the formation sand filling module.

[0090] During the experiment, the data automatically tested and collected according to the set time step Δt include: Q i —Liquid flow rate after the ith adjustment, m 3 / s; ΔP i —The total pressure drop from the outlet to the inlet of the formation sand filling module after the i-th flow adjustment, MPa; the data tested manually include: T i—Displacement time corresponding to the flow rate after the ith adjustment, s; m i k—the amount of sand produced measured for the kth time after the flow rate was adjusted for the ith time, g.

[0091] The calculation method of sand stabilization performance index is as follows:

[0092]

[0093] In formula (1), C m —Sand stabilization performance index; v0——Sand production speed after pumping sand stabilizer, sand production after pumping sand stabilizer The slope of the fitting curve with time is obtained, g / s; v′0——sand production velocity before pumping sand stabilizer, and the sand production before pumping sand stabilizer The slope of the fitting curve with time, g / s, was obtained by the above test method.

[0094] The calculation method of circulation performance index is as follows:

[0095]

[0096] In formula (2), C k —Flow performance index; k0——core permeability after pumping sand stabilizer, calculated by Darcy formula, μm 2 ; k'0——core permeability before pumping sand stabilizer, calculated by Darcy's formula, μm 2 .

[0097] The calculation method of the erosion resistance performance index is as follows:

[0098]

[0099] In formula (3), C q —Erosion resistance performance index; q——Erosion resistance flow rate of sand stabilizer, that is, the flow rate after pumping sand stabilizer under the same sand production speed as when the flow rate before pumping sand stabilizer is q0, mL / min, measured by the above test method; q0——The flow rate before pumping sand stabilizer, the experiment is generally set to 100mL / min.

[0100] The calculation method of comprehensive sand control performance index is as follows:

[0101] C ssp =f m C m +f k C k +f q C q (4)

[0102] f m +fk +f q =1 (5)

[0103] In formula (4) and (5), C ssp It is the comprehensive performance index of sand stabilizer; m is the weight coefficient of sand stabilization performance; f k is the flow performance weight coefficient; f q is the weight coefficient of erosion resistance performance. m C is the sand stabilization performance index; k Is the flow performance index; C q It is an indicator of erosion resistance performance.

[0104] If the oil field production focuses on ensuring that the target oil well does not produce sand in the near future, the weight coefficients of sand stabilization performance, flow performance and erosion resistance performance are 0.5, 0.3 and 0.2 respectively.

[0105] If the oil field production focuses on prioritizing the high production of the target oil wells in the near term, the weight coefficients of sand stabilization performance, flow performance, and erosion resistance performance are 0.2, 0.5, and 0.3, respectively.

[0106] Calculation method for the minimum treatment radius of sand stabilizer at oil field site:

[0107] If the erosion resistance performance index of the sand stabilizer is C q <1.5, the sand stabilizer is considered substandard and is not recommended for use; if the erosion resistance index C q ≥1.5, it means that the sand stabilizer has practical applicability and can be used. Then, the minimum treatment radius is calculated based on the erosion resistance flow rate q of the sand stabilizer measured by its test method. The method is as follows:

[0108] The formation flow distribution curve is shown in formula (6):

[0109]

[0110] In formula (6): Q N - formation flow rate, mL / min; h—effective reservoir thickness, m; φ—reservoir porosity, %; K h —Average formation permeability, μm 2 ; μ—fluid viscosity, using the actual viscosity of the displacement fluid used in the experiment, MPa·s; P e —formation pressure, MPa; P w —Bottomhole flowing pressure, MPa; R w —Wellbore radius, m; R e —formation oil supply radius, m; R—formation radius, m.

[0111] Input parameters h, φ, K h,μ,P e , P, R w , R e After that, the horizontal flow distribution curve of the bottom formation of the production well can be obtained.

[0112] Using this flow distribution curve, let Q N =q, we can get the formation radius R corresponding to the erosion resistance flow rate q of the sand stabilizer. The formation radius R is the minimum treatment radius Rc of the sand stabilizer, in m.

[0113] Example 3

[0114] The experimental device used in the present invention includes a liquid storage tank 1, a horizontal flow pump liquid supply module 2, a formation sand filling module 3, a sand-liquid separation and collection module 4, a waste liquid collection container 5, and an intermediate container module 6 connected in parallel on the pipeline between the horizontal flow pump liquid supply module 2 and the formation sand filling module 3 through a pipeline. The experimental device also includes a front pressure sensor 7 and a flow sensor 8 arranged on the outlet pipeline of the horizontal flow pump liquid supply module 2, a rear pressure sensor 9 arranged on the outlet pipeline of the formation sand filling module 3, and a data acquisition system module 10 respectively connected to the horizontal flow pump liquid supply module 2, the front pressure sensor 7, the flow sensor 8, and the rear pressure sensor 9. The test steps include:

[0115] Step 1, after weighing the formation sand filling module, connect it to the experimental system, put the sand stabilizing agent into the intermediate container module 6 and keep the intermediate container module closed;

[0116] Step 2, set the pump flow rate Q0 and start the advection pump liquid supply module 2, and record the sand output of the formation sand filling module displayed in the sand-liquid separation and collection module 4 at every time step Δt;

[0117] Step 3, after the fluid pressure of the formation sand filling module is stable at time T0, turn off the horizontal flow pump liquid supply module 2, stop pumping liquid into the formation sand filling module, and record the sand output of the formation sand filling module at this time, and record the pressure at the inlet and outlet of the formation sand filling module in real time through the front pressure sensor 7 and the rear pressure sensor 9;

[0118] Step 4, open the valves at both ends of the intermediate container module 6, and close the valve on the pipeline between the horizontal flow pump liquid supply module 2 and the formation sand filling module 3, start the horizontal flow pump liquid supply module 2 to inject all the sand stabilizer in the intermediate container module 6 into the formation sand filling module at a low flow rate (less than 40mL / min), close the experimental system, and wait for the sand stabilizer to consolidate;

[0119] Step 5, set the pump flow rate Q0 and start the horizontal flow pump liquid supply module 2 to pump liquid into the formation sand filling module, record the sand output of the formation sand filling module at every time step Δt, and record the pressure at the inlet and outlet of the formation sand filling module in real time;

[0120] Step 6, after the fluid pressure of the formation sand filling module is stable at time T1, the sand output of the formation sand filling module displayed in the sand-liquid separation and collection module 4 is recorded;

[0121] Step 7, adjust the pump flow to Q1 and repeat steps 5-6 until the pump flow is adjusted to Q i , and at T i After the fluid pressure of the formation sand filling module is stable, record the sand output of the formation sand filling module at this time

[0122] Step 8, stop pumping liquid into the formation sand filling module, dismantle the experimental device, dismantle the formation sand filling module and the intermediate container module, and clean and dry them.

[0123] Calculation method of sand stabilization performance index. Sand stabilization performance refers to the basic control ability of sand stabilizer on the spalling and migration of formation sand particles, which is reflected in the ratio of the sand production rate after pumping sand stabilizer to the sand production rate before pumping sand stabilizer at a flow rate of 100mL / min (i.e. Q0). It is proposed to use the sand stabilization performance index C v Characterization, the calculation formula is:

[0124]

[0125] In formula (1), C m —Sand stabilization performance index; v0——Sand production speed after pumping sand stabilizer, sand production after pumping sand stabilizer The slope of the fitting curve with time is obtained, g / s; v′0——sand production velocity before pumping sand stabilizer, and the sand production before pumping sand stabilizer The slope of the fitted curve with time is obtained, g / s.

[0126] The sand production velocity v is obtained according to the slope of the regression curve of sand production and time. For example, at the flow rate Q i The following data are measured as shown in Table 1, and the curve is fitted according to Table 1 as shown in Figure 2 As shown, the sand production speed under this flow rate is obtained according to the slope of the curve.

[0127] Table 1 Relationship between sand production and displacement time under different flow rates Q

[0128]

[0129] The calculation method of circulation performance index is as follows:

[0130]

[0131] In formula (2), C k—Flow performance index; k0——core permeability after pumping sand stabilizer, calculated by Darcy formula, μm 2 ; k'0——core permeability before pumping sand stabilizer, calculated by Darcy's formula, μm 2 .

[0132] The fluid flow capacity of the sand filling module after the sand stabilizer is injected to consolidate the sandstone during the displacement process at a flow rate of 100 mL / min (i.e., Q0) is expressed by the permeability. The higher the overall permeability, the smaller the fluid flow resistance. In the experiment, the flow performance is the ratio of the stable permeability after the sand stabilizer is injected to the stable permeability before the sand stabilizer is injected. The permeability performance index C is proposed. k Representation.

[0133] The calculation method of the erosion resistance performance index is as follows:

[0134]

[0135] In formula (3), C q —Erosion resistance performance index; q——Erosion resistance flow rate of sand stabilizer, that is, the flow rate after pumping sand stabilizer under the same sand production speed as when the flow rate before pumping sand stabilizer is q0, mL / min, measured by the above test method; q0——The flow rate before pumping sand stabilizer, the experiment is generally set to 100mL / min.

[0136] The scour resistance performance is the degree of improvement of the scour resistance flow rate of the core treated with the sand stabilizer relative to the scour resistance flow rate of the untreated core. The sand production velocity v′0 of the untreated core under the condition of q0 flow rate clear water displacement is measured, and the core treated with the sand stabilizer is displaced to measure its sand production velocity. The experimental flow rate is gradually increased. When the sand production velocity is close to the original sand production velocity v′0, it is the scour resistance flow rate q of the sand stabilizer. The scour resistance performance index C q Used to characterize the erosion resistance during the production process of sand stabilizer.

[0137] The calculation method of comprehensive sand control performance index is as follows:

[0138] C ssp =f m C m +f k C k +f q C q (4)

[0139] f m +f k +f q =1 (5)

[0140] In formula (4) and (5), C ssp It is the comprehensive performance index of sand stabilizer;m is the weight coefficient of sand stabilization performance; f k is the flow performance weight coefficient; f q It is the weight coefficient of erosion resistance performance.

[0141] The comprehensive sand control performance of the sand stabilizer is a comprehensive reflection of various performances. According to the sand stabilization performance index C m , circulation performance index C k , erosion resistance performance index C q Calculated by weighted average.

[0142] The weight coefficient is an empirical coefficient, which is selected according to the production requirements of different oil fields, as shown in Table 2. If the oil field production focuses on the priority of ensuring that the target oil well does not produce sand in the near future, that is, the sand stabilizer needs to have high sand stabilization performance and high scouring resistance, and can achieve the goal of long-term sand stabilization, then the recommended sand stabilization performance weight coefficient, circulation performance weight coefficient, and scouring resistance weight coefficient are 0.5, 0.3, and 0.2 respectively. If the oil field production focuses on giving priority to ensuring the high production of the target oil well in the near future, that is, the sand stabilizer is required to have low damage to the reservoir permeability, then the recommended sand stabilization performance weight coefficient, circulation performance weight coefficient, and scouring resistance weight coefficient are 0.2, 0.5, and 0.3 respectively. If there are other production requirements, adjust the weight coefficients as needed.

[0143] Table 2 Recommended weight coefficients

[0144]

[0145]

[0146] Calculation method for the minimum treatment radius of sand stabilizer at oil field site:

[0147] The sand stabilizer cannot be guaranteed to be stably attached to the sandstone under the action of fluid dynamics. When the flow rate increases to a certain limit, most of the sand stabilizer will be directly washed away, resulting in sand control failure. This limit value is called the erosion resistance flow rate of the sand stabilizer. Erosion resistance performance index C q A value not less than 1.5 can ensure that the selected sand stabilizer can effectively and efficiently prevent sand production in the oil field.

[0148] The above test experiment was carried out with clean water with a viscosity of 1 mPa·s. If the scour resistance performance index C of the sand stabilizer q <1.5, the sand stabilizer is considered substandard and is not recommended for use; if the erosion resistance index C q ≥1.5, it means that the sand stabilizer has practical applicability and can be used. Then, the minimum treatment radius is calculated based on the erosion resistance flow rate q of the sand stabilizer measured by its test method. The method is as follows:

[0149] The velocity distribution curve in the horizontal direction of the formation is obtained by the velocity field distribution model proposed in the prior art. By assuming that the formation permeability is isotropic, a simplified velocity distribution model is obtained. The present invention obtains the formation flow distribution curve by multiplying the velocity with the formation flow area as shown in formula (6).

[0150]

[0151] Where: Q N - formation flow rate, mL / min; h—effective reservoir thickness, m; φ—reservoir porosity, %; K h —Average formation permeability, μm 2 ; μ—fluid viscosity, using the actual viscosity of the displacement fluid used in the experiment, MPa·s; P e —formation pressure, MPa; P w —Bottomhole flowing pressure, MPa; R w —Wellbore radius, m; R e —formation oil supply radius, m; R—formation radius, m.

[0152] Input parameters h, φ, K h ,μ,P e , P, R w , R e After that, the horizontal flow distribution curve of the bottom formation of the production well can be obtained.

[0153] Using this flow distribution curve, let Q N =q, we can get the formation radius R corresponding to the erosion resistance flow rate q of the sand stabilizer, and the formation radius R is the minimum treatment radius Rc of the sand stabilizer, in m;

[0154] During construction, the pumped sand stabilizer should be larger than the minimum treatment radius (R c , unit: m). If it is smaller than the treatment radius, the sand stabilizing agent is very likely to be washed away by the fluid within a short time after the well is opened for production, resulting in extremely poor sand stabilization and sand prevention effects.

[0155] The present invention relates to the technical field of well completion engineering for resources such as petroleum and natural gas, and discloses a method for testing and evaluating the sand control performance of a sand stabilizer. The actual sand control performance of the sand stabilizer under an actual construction environment is restored to a greater extent by experimentally simulating the construction procedures of sand stabilizer pumping, well shut-in and waiting for solidification, and well opening with variable flow production. The dynamic data such as displacement flow, displacement pressure difference, and sand output before and after the sand stabilizer is pumped are tested to evaluate the comprehensive sand control effect of the sand stabilizer; comprehensive quantitative evaluation indicators and evaluation methods such as sand stabilization performance, flow performance, and scour resistance performance of the sand stabilizer are constructed to compare different sand stabilizers; the scour resistance flow rate is obtained through the specified scour resistance performance index, thereby obtaining the applicable treatment radius range of the sand stabilizer. The experimental method, data processing, and evaluation method provided for the evaluation of the comprehensive sand control performance of the sand stabilizer can be used in the sand control process design of oil wells to provide efficient and long-lasting sand stabilization effects.

[0156] Although the above describes the specific implementation mode of the invention in conjunction with the drawings, it is not intended to limit the scope of protection of the invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for testing and evaluating the sand control performance of a sand stabilizer, characterized in that: The sand stabilizing agent sand control performance test and evaluation method includes: Step 1, set the pump flow rate to Q0, pump liquid into the formation sand filling module, and record the sand output; Step 2: After the fluid pressure is stable, stop pumping the liquid and record the amount of sand produced at this time; Step 3, pumping a sand stabilizer into the formation sand filling module and waiting for the sand stabilizer to solidify; Step 4, set the pump flow rate to Q0, pump liquid into the formation sand filling module again, and record the sand output; Step 5, after the fluid pressure is stable, record the amount of sand produced; Step 6: Adjust the pump flow rate to Q1 and repeat steps p4-5 until the fluid pressure stabilizes, and record the sand output at this time.

2. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: The sand stabilizer sand control performance testing and evaluation method also includes, before step 1, weighing the formation sand filling module and then connecting it to the experimental system.

3. The sand stabilizing agent sand control performance testing and evaluation method according to claim 1, characterized in that: In step 1, the pump flow rate Q0 is set and the liquid pump is started to pump liquid into the formation sand filling module, and the sand output of the formation sand filling module is recorded at every time step Δt.

4. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: In step 2, after the fluid pressure of the formation sand filling module stabilizes at time T0, stop pumping liquid into the formation sand filling module, and record the sand output of the formation sand filling module at this time, and record the pressure at the inlet and outlet of the formation sand filling module in real time, and calculate the total pressure drop from the outlet to the inlet of the formation sand filling module.

5. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: In step 4, the pump flow rate Q0 is set and the liquid pump is started to pump liquid into the formation sand filling module. The sand output of the formation sand filling module is recorded at each time step Δt, and the pressure at the inlet and outlet of the formation sand filling module is recorded in real time.

6. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: In step 5, after the fluid pressure of the formation sand filling module is stabilized at time T1, the sand output of the formation sand filling module at this time is recorded.

7. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: In step 6, adjust the pump flow to Q1 and repeat steps 4-5 until the pump flow is adjusted to Q i , and at T i After the fluid pressure of the formation sand filling module is stable, record the sand output m of the formation sand filling module at this time i k .

8. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 1, characterized in that: The sand stabilizing agent sand control performance testing and evaluation method further includes, after step 6, step 7, stopping pumping liquid into the formation sand filling module.

9. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 8, characterized in that: The sand control performance testing and evaluation method of the sand stabilizer also includes, after step 7, step 8, calculating the sand stabilization performance index, the flow performance index, the comprehensive sand control performance index and the minimum treatment radius.

10. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, the sand stabilization performance index calculation formula is: In formula (1), C m —Sand stabilization performance index; v0——Sand production speed after pumping sand stabilizer, sand production after pumping sand stabilizer The slope of the fitting curve with time is obtained, g / s; v′0——sand production velocity before pumping sand stabilizer, and the sand production before pumping sand stabilizer The slope of the fitting curve with time, g / s, was obtained by the above test method.

11. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, the flow performance index calculation formula is: In formula (2), C k —Flow performance index; k0——core permeability after pumping sand stabilizer, calculated by Darcy formula, μm 2 ; k′0——core permeability before pumping sand stabilizer, calculated by Darcy formula, μm 2 .

12. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, the calculation formula for the erosion resistance performance index is: In formula (3), C q —Erosion resistance performance index; q——Erosion resistance flow rate of sand stabilizer, that is, the flow rate after pumping sand stabilizer under the same sand production speed as when the flow rate before pumping sand stabilizer is q0, mL / min, measured by the above test method; q0——The flow rate before pumping sand stabilizer, the experiment is generally set to 100mL / min.

13. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, the comprehensive sand control performance index calculation formula is: C ssp =f m C m +f k C k +f q C q (4) f m +f k +f q =1 (5) In formula (4) and (5), C ssp It is the comprehensive performance index of sand stabilizer; m is the weight coefficient of sand stabilization performance; f k is the flow performance weight coefficient; f q is the weight coefficient of erosion resistance performance; m C is the sand stabilization performance index; k Is the flow performance index; C q It is an indicator of erosion resistance performance.

14. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, if the oilfield production focuses on optimizing and ensuring that the target oil well does not produce sand in the near future, the weight coefficients of sand stabilization performance, flow performance, and erosion resistance performance are 0.5, 0.3, and 0.2 respectively; If the oil field production focuses on prioritizing the high production of the target oil wells in the near term, the weight coefficients of sand stabilization performance, flow performance, and erosion resistance performance are 0.2, 0.5, and 0.3, respectively.

15. The method for testing and evaluating the sand control performance of a sand stabilizer according to claim 9, characterized in that: In step 8, the calculation method of the minimum treatment radius of the sand stabilizing agent at the oil field site is: If the erosion resistance performance index of the sand stabilizer is C q <1.5, the sand stabilizer is considered substandard and is not recommended for use; if the erosion resistance index C q ≥1.5, it means that the sand stabilizer has practical applicability and can be used. Then, the minimum treatment radius is calculated based on the erosion resistance flow rate q of the sand stabilizer measured by its test method. The method is as follows: The formation flow distribution curve is shown in formula (6): In formula (6): Q N - formation flow rate, mL / min; h—effective reservoir thickness, m; φ—reservoir porosity, %; K h —Average formation permeability, μm 2 ; μ—fluid viscosity, using the actual viscosity of the displacement fluid used in the experiment, MPa·s; P e —formation pressure, MPa; P w —Bottomhole flowing pressure, MPa; R w —Wellbore radius, m; R e —formation oil supply radius, m; R—formation radius, m; Input parameters h, φ, K h ,μ,P e , P, R w , R e After that, the horizontal flow distribution curve of the bottom formation of the production well can be obtained; Using this flow distribution curve, let Q N =q, we can get the formation radius R corresponding to the erosion resistance flow rate q of the sand stabilizer. The formation radius R is the minimum treatment radius Rc of the sand stabilizer, in m.

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