An acidizing huff and puff experiment system and experiment method

Abstract

The application discloses an acidizing soak well experiment system and an experiment method, relates to the field of core detection in oil and gas wells, and comprises a horizontal flow input device, a formation water flow channel, an acid liquid flow channel and a total flow channel. The formation water flow channel and the acid liquid flow channel are arranged side by side and are communicated with the total flow channel. The horizontal flow input device is configured to drive formation water in the formation water flow channel or acid liquid in the acid liquid flow channel into the total flow channel. The total flow channel is further connected with a core clamping structure which is configured to fix a sampling core so that the formation water or the acid liquid entering the total flow channel can flow through the sampling core. The technology can simulate acidizing soak well experiments on cores and detect the cores at various time nodes, and can more comprehensively and accurately reflect the physical characteristics of the cores before and after acidizing soak well.

Description

Technical Field

[0001] This invention relates to the field of core testing in oil and gas wells, specifically to an acidizing well shut-in test system and method. Background Technology

[0002] Acidizing is an effective technique for increasing production in oil and gas wells or increasing water injection in water injection wells. Its principle is to restore or improve the permeability of formation pores and fractures by dissolving and eroding rock cement or blockages in formation pores and fractures with acid.

[0003] Currently, oil fields generally use fracturing fluid to simmer wells, which alters the physical properties of the oil-bearing rock and increases crude oil production.

[0004] Nowadays, most oilfields immediately carry out flowback operations after reservoir acid treatment (acidification or acid fracturing, etc.) for the following reasons: to prevent the acid from damaging the reservoir skeleton and the products of the reaction between the acid and the reservoir rock from damaging the reservoir.

[0005] However, this also leads to incomplete acid reactions, preventing the formation of effective pores in the reservoir rock and significantly shortening the effective range of the acid. Summary of the Invention

[0006] Based on the problems existing in the current technology, this invention proposes an acidizing well-shutting test system and method, optimizes the on-site construction parameters, and uses a weak acid system such as slow-release acid to conduct acidizing well-shutting experiments, reduces the damage of acid to the reservoir skeleton, reduces the damage of the products of the reaction between acid and reservoir rock to the reservoir, and at the same time improves the acid treatment effect and increases oil and gas production.

[0007] Specifically, the detailed technical solution proposed in this invention is as follows:

[0008] An acidizing well shut-in test system includes a horizontal flow input device, a formation water flow channel, an acid flow channel, and a main flow channel;

[0009] The formation water channel and the acid channel are arranged in parallel and converge to connect with the main channel; the horizontal flow input device is configured to drive the formation water in the formation water channel or the acid in the acid channel into the main channel respectively.

[0010] The main flow channel is also connected to a core clamping structure, which is configured to fix the sampled core so that formation water or acid entering the main flow channel can flow through the sampled core.

[0011] Furthermore, a first three-way connection switch is provided in the main flow channel, and the first three-way connection switch is located in front of the core clamping structure; the formation water flow channel and the acid flow channel are connected to the main flow channel through the first three-way connection switch; an inlet pressure gauge is also connected to the first three-way connection switch;

[0012] The main flow channel is also equipped with a second three-way connection switch, which is located behind the core clamping structure and is also connected to an outlet pressure gauge.

[0013] Furthermore, the core clamping structure includes a clamp and a ring clamp, wherein the sampled core is placed in the clamp and fixed by the ring clamp.

[0014] Furthermore, a first intermediate container is provided in the formation water channel, and the first intermediate container contains formation water.

[0015] Furthermore, a second intermediate container is provided in the acid flow channel, and the second intermediate container contains acid.

[0016] Furthermore, the advection input device includes a first advection pump and a second advection pump, wherein the first advection pump is connected to the first intermediate container; and the second advection pump is connected to the second intermediate container.

[0017] Furthermore, a solution receiver is connected to the tail end of the main flow channel.

[0018] Furthermore, the formation water channel, acid channel, and main channel are all placed inside a constant temperature chamber.

[0019] Based on the above experimental system, the present invention also provides an experimental method, namely an acidification well shut-in experimental method, which uses the system described above for operation and experimentation, and the specific steps are as follows:

[0020] Step 1: Before the test begins, check the sealing of each pipeline. The pipeline is made of Hastelloy alloy. Check the connection of the pipeline joints and check the flow control of the horizontal flow input.

[0021] Step 2: Place the sampled rock core in the nuclear magnetic resonance analysis and imaging system for online detection of physical parameters, and record the detection results R1;

[0022] Step 3: Close all valves, place the sampled core into the holder, fix the sampled core in the holder using the ring clamp, connect all pipelines according to the system design drawing, and set the temperature in the constant temperature chamber to the required value;

[0023] Step 4: Open the first three-way connection switch, turn on the first advection pump to smoothly push the formation water injected in the first intermediate container into the clamp, record the data of the inlet pressure gauge and the outlet pressure gauge, record the data as F1 when the outlet flow rate is consistent with the inlet flow rate, and then turn off the first advection pump;

[0024] Step 5: Turn on the second horizontal flow pump to smoothly push the acid solution injected in the second intermediate container into the clamp, observe the values ​​displayed on the inlet and outlet pressure gauges, and adjust the flow rate using the second horizontal flow pump;

[0025] Step 6: When the value on the outlet pressure gauge changes significantly, and the unit time flow rate of the solution receiver is the same as the flow rate set by the second parallel flow pump, close the first three-way connection switch, turn off the second parallel flow pump, and collect the residual liquid in the solution receiver.

[0026] Step 7: Open the first three-way connection switch, turn on the first horizontal flow pump to smoothly push the formation water injected in the first intermediate container into the clamp. When the outlet flow rate is consistent with the inlet flow rate, record the data F2 of the inlet pressure gauge and the outlet pressure gauge. Turn off the first horizontal flow pump and turn off the thermostat.

[0027] Step 8: Perform online detection of physical parameters on the sampled core after acid displacement using a nuclear magnetic resonance analysis and imaging system, and record the detection results R2;

[0028] Step 9: Place the sampled core back into the holder, keep other conditions unchanged, inject the residual liquid obtained in Step 5 into the second intermediate container, turn on the second horizontal flow pump, and smoothly push the residual liquid in the second intermediate container into the holder, and observe the values ​​displayed by the inlet pressure gauge and the outlet pressure gauge.

[0029] Step 10: When the value on the outlet pressure gauge changes significantly, and the unit time flow rate value connected to the solution receiver is the same as the flow rate value set by the second parallel flow pump, close the second three-way connection switch, close the first three-way connection switch, close the second parallel flow pump, and carry out acidification well shut-off according to the experimental design time.

[0030] Step 11: Open the second three-way connection switch, open the first three-way connection switch, discharge the residual acid to the solution receiver, turn on the first horizontal flow pump to steadily push the formation water injected in the first intermediate container into the holder, and when the outlet flow rate is consistent with the inlet flow rate, record the data F3 of the inlet pressure gauge and the outlet pressure gauge, turn off the first horizontal flow pump, turn off the constant temperature chamber, and take out the sampled rock core from the holder;

[0031] Step 12: Perform online detection of physical parameters on the core samples taken after the acidizing and simmering experiment using a nuclear magnetic resonance analysis and imaging system, and record the detection results R3;

[0032] Step 13: Analyze and process the liquid measurement data F1, F2, and F3, analyze the data and images of R1, R2, and R3 obtained from the nuclear magnetic resonance analysis and imaging system, and analyze and compare the data with relevant data from wells that have not undergone acidizing and shut-in experiments.

[0033] The beneficial effects achieved by adopting this technical solution are as follows:

[0034] This technology simulates acidizing and well-shutting experiments on core samples and analyzes the core samples at various time points, providing a more comprehensive and accurate reflection of the physical properties of the core samples before and after acidizing and well-shutting. The acid used is a weak acid system, such as solid acid or slow-release acid, allowing the acid to react with more reservoir rocks and achieve a longer effective contact distance. Furthermore, the byproducts of the interaction between the solid acid and the reservoir rocks cause less damage to the reservoir.

[0035] 1. The entire core acidizing process utilizes a nuclear magnetic resonance (NMR) analysis and imaging system for non-destructive online property testing. First, the sampled core undergoes non-destructive online property testing (R1), followed by liquid property testing (F1). Then, the tested weak acid solution is injected for acidizing experiments, followed by another round of non-destructive online property testing (R2) and liquid property testing (F2). Finally, residual acid is injected for acidizing and well-shutting experiments, followed by a third round of non-destructive online property testing (R3) and liquid property testing (F3).

[0036] 2. Indoor experimental simulation of well shut-in after acidizing. The inlet and outlet switches designed at the front and rear of the clamp can effectively simulate the conditions required for well shut-in after acidizing, allowing the acid to be maintained at a certain pressure and temperature for a certain period of time. This design enables the simulation of well shut-in experiments in the laboratory, and also enables experimental schemes for immediate switching between acid and matrix fluids such as formation water.

[0037] 3. Utilize NMR (low-field nuclear magnetic resonance) technology to dynamically monitor changes in core physical properties. Because NMR systems allow real-time observation of core physical properties during acidizing experiments, and by varying the time and acid concentration, the physical properties of the same sampled core at any given time point can be obtained. Analyzing and processing this data can help predict whether acidizing and shutting down oil wells will increase oil and gas production.

[0038] 4. Changes before and after NMR (low-field nuclear magnetic resonance) real-time imaging. The physical properties of core samples obtained by NMR before the acidizing well-suppression experiment were processed and analyzed, along with the physical properties obtained by NMR after the experiment. Furthermore, the data from the acidizing well-suppression experiment and the fracturing fluid well-suppression experiment were processed and analyzed to explore whether the acidizing well-suppression experiment effectively increased the permeability of the sampled core and whether it formed more vermiform pores. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the system's principle structure.

[0040] The components include: 10 Horizontal flow input device, 11 First horizontal flow pump, 12 Second horizontal flow pump, 20 Formation water flow channel, 21 First intermediate container, 30 Acid flow channel, 31 Second intermediate container, 40 Main flow channel, 41 First three-way connection switch, 42 Inlet pressure gauge, 43 Second three-way connection switch, 44 Outlet pressure gauge, 45 Solution receiver, 51 Clamp, 52 Ring pressure device, and 100 Constant temperature chamber. Detailed Implementation

[0041] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0042] This embodiment provides an acidizing well-steaming test system. By using the test system designed in this scheme to test the sampled rock core, the physical properties of the rock core before and after acidizing well-steaming can be reflected more comprehensively and accurately in actual operation.

[0043] For details, see Figure 1 The experimental system in this scheme includes a flow input device 10, a formation water channel 20, an acid channel 30, and a main channel 40. Specifically, the formation water channel 20 and the acid channel 30 are arranged in parallel and converge to connect with the main channel 40. The flow input device 10 is configured to drive the formation water in the formation water channel 20 or the acid in the acid channel 30 into the main channel 40. At the same time, a core clamping structure is connected in the main channel 40. The core clamping structure is configured to fix the sampled core so that the formation water or acid entering the main channel 40 can flow through the sampled core.

[0044] The above system structure is used to complete the testing of the sampled rock core. In order to ensure real-time monitoring of the state of the sampled rock core, a nuclear magnetic resonance (NMR) analysis and imaging system is used. The NMR analysis and imaging system can display the pore distribution map, oil-water distribution and T2 spectrum of the rock core in the form of data and images.

[0045] To facilitate a deeper understanding of this solution, the specific components and structure of the system will be described in detail below.

[0046] In this scheme, a first three-way connection switch 41 is provided in the main flow channel 40, and the first three-way connection switch 41 is located in front of the core clamping structure; the formation water flow channel 20 and acid flow channel 30 mentioned above are connected to the main flow channel 40 through the first three-way connection switch 41; and an inlet pressure gauge 42 is also connected to the first three-way connection switch 41; a second three-way connection switch 43 is also provided in the main flow channel 40, the second three-way connection switch 43 is located behind the core clamping structure and an outlet pressure gauge 44 is also connected to the second three-way connection switch 43.

[0047] Optionally, a solution receiver 45 is connected to the tail end of the main flow channel 40.

[0048] In a specific embodiment of this solution, the core clamping structure includes a clamp 51 and a ring clamp 52. The sampled core is placed in the clamp 51 and fixed by the ring clamp 52. Through this core clamping structure, the core can be stably clamped and fixed, and the fluid (formation water or acid) in the main flow channel 40 can be guided to flow through the core.

[0049] In this scheme, a first intermediate container 21 is provided in the formation water channel 20, and the first intermediate container 21 contains formation water. At the same time, a second intermediate container 31 is provided in the acid flow channel 30, and the second intermediate container 31 contains acid.

[0050] Meanwhile, the advection input device 10 includes a first advection pump 11 and a second advection pump 12. The first advection pump 11 is connected to the first intermediate container 21; the second advection pump 12 is connected to the second intermediate container 31.

[0051] The formation water channel 20, acid channel 30, and main channel 40 are all placed inside a constant temperature chamber 100. The constant temperature chamber 100 is used to control the temperature of the entire experiment, effectively simulating the actual conditions on site.

[0052] Based on the above experimental system, the present invention also provides an experimental method, namely an acidification well shut-in experimental method, which uses the above system for operation and experimentation, and the specific steps are as follows:

[0053] Step 1: Before the test begins, check the sealing of each pipeline. The pipeline is made of Hastelloy alloy. Check the connection of the pipeline joints and check the flow control of the horizontal flow input.

[0054] Step 2: Place the sampled rock core in the nuclear magnetic resonance analysis and imaging system for online detection of physical parameters, and record the detection results R1.

[0055] Step 3: Close all valves, place the sampled core into the holder 51, fix the sampled core in the holder 51 using the ring clamp 52, connect all pipelines according to the system design drawing, and set the temperature in the constant temperature chamber 100 to the required value.

[0056] Step 4: Open the first three-way connection switch 41, turn on the first horizontal flow pump 11 to smoothly push the formation water injected in the first intermediate container 21 into the clamp 51, record the data of the inlet pressure gauge 42 and the outlet pressure gauge 44, record the data as F1 when the outlet flow rate is consistent with the inlet flow rate, and then turn off the first horizontal flow pump 11.

[0057] Optionally, after step four is completed, the sampled core can be removed from the holder 51 and the porosity effect in the core can be visualized in detail using CT. After the results are obtained, the sampled core is put back into the holder 51 and fixed using the ring clamp 52.

[0058] Step 5: Turn on the second horizontal flow pump 12 to smoothly push the acid solution injected in the second intermediate container 31 into the clamp 51, observe the values ​​displayed by the inlet pressure gauge 42 and the outlet pressure gauge 44, and adjust the flow rate through the second horizontal flow pump 12.

[0059] Step 6: When the value on the outlet pressure gauge 44 changes significantly, and the unit time flow rate value connected to the solution receiver 45 is the same as the flow rate value set by the second parallel flow pump 12, close the first three-way connection switch 41, turn off the second parallel flow pump 12, and collect the residual liquid in the solution receiver 45.

[0060] Step 7: Open the first three-way connection switch 41, turn on the first horizontal flow pump 11 to smoothly push the formation water injected in the first intermediate container 21 into the clamp 51. When the outlet flow rate is consistent with the inlet flow rate, record the data F2 of the inlet pressure gauge 42 and the outlet pressure gauge 44. Turn off the first horizontal flow pump 11 and turn off the constant temperature chamber 100.

[0061] Step 8: Perform online detection of physical parameters on the sampled core after acid displacement using a nuclear magnetic resonance analysis and imaging system, and record the detection results R2.

[0062] Step 9: Place the sampled core back into the holder 51, keep other conditions unchanged, inject the residual liquid obtained in Step 5 into the second intermediate container 31, turn on the second horizontal flow pump 12, and smoothly push the residual liquid in the second intermediate container 31 into the holder 51, and observe the values ​​displayed by the inlet pressure gauge 42 and the outlet pressure gauge 44.

[0063] Step 10: When the value on the outlet pressure gauge 44 changes significantly, and the unit time flow rate value connected to the solution receiver 45 is the same as the flow rate value set by the second parallel flow pump 12, close the second three-way connection switch 43, close the first three-way connection switch 41, close the second parallel flow pump 12, and carry out acidification well shut-off according to the experimental design time.

[0064] Step 11: Open the second three-way connection switch 43, open the first three-way connection switch 41, discharge the residual acid to the solution receiver 45, turn on the first horizontal flow pump 11 to smoothly push the formation water injected in the first intermediate container 21 into the holder 51, and record the data F3 of the inlet pressure gauge and outlet pressure gauge when the outlet flow rate is consistent with the inlet flow rate. Turn off the first horizontal flow pump, turn off the constant temperature chamber, and take out the sampled rock core from the holder.

[0065] Step 12: Perform online detection of physical parameters on the core samples taken after the acidizing and simmering experiment using a nuclear magnetic resonance analysis and imaging system, and record the detection results R3;

[0066] Step 13: Analyze and process the liquid measurement data F1, F2, and F3, analyze the data and images of R1, R2, and R3 obtained from the nuclear magnetic resonance analysis and imaging system, and analyze and compare the data with relevant data from wells that have not undergone acidizing and shut-in experiments.

[0067] This technology simulates acidizing and well-shutting experiments on core samples and analyzes the core samples at various time points, providing a more comprehensive and accurate reflection of the physical properties of the core samples before and after acidizing and well-shutting. The acid used is a weak acid system, such as solid acid or slow-release acid, allowing the acid to react with more reservoir rocks and achieve a longer effective contact distance. Furthermore, the byproducts of the interaction between the solid acid and the reservoir rocks cause less damage to the reservoir.

[0068] At the same time, by using the experimental methods mentioned in this system, at least the following beneficial effects can be achieved.

[0069] 1. The entire core acidizing process utilizes a nuclear magnetic resonance (NMR) analysis and imaging system for non-destructive online property testing. First, the sampled core undergoes non-destructive online property testing (R1), followed by liquid property testing (F1). Then, the tested weak acid solution is injected for acidizing experiments, followed by another round of non-destructive online property testing (R2) and liquid property testing (F2). Finally, residual acid is injected for acidizing and well-shutting experiments, followed by a third round of non-destructive online property testing (R3) and liquid property testing (F3).

[0070] 2. Indoor experimental simulation of well shut-in after acidizing. The inlet and outlet switches designed at the front and rear of the clamp can effectively simulate the conditions required for well shut-in after acidizing, allowing the acid to be maintained at a certain pressure and temperature for a certain period of time. This design enables the simulation of well shut-in experiments in the laboratory, and also enables experimental schemes for immediate switching between acid and matrix fluids such as formation water.

[0071] 3. Utilize NMR (low-field nuclear magnetic resonance) technology to dynamically monitor changes in core physical properties. Because NMR systems allow real-time observation of core physical properties during acidizing experiments, and by varying the time and acid concentration, the physical properties of the same sampled core at any given time point can be obtained. Analyzing and processing this data can help predict whether acidizing and shutting down oil wells will increase oil and gas production.

[0072] 4. Changes before and after NMR (low-field nuclear magnetic resonance) real-time imaging. The physical properties of core samples obtained by NMR before the acidizing well-suppression experiment were processed and analyzed, along with the physical properties obtained by NMR after the experiment. Furthermore, the data from the acidizing well-suppression experiment and the fracturing fluid well-suppression experiment were processed and analyzed to explore whether the acidizing well-suppression experiment effectively increased the permeability of the sampled core and whether it formed more vermiform pores.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for acidification well steaming experiment, characterized in that, An acidizing well-steaming test system was used for operation experiments; the acidizing well-steaming test system includes a horizontal flow input device (10), a formation water flow channel (20), an acid flow channel (30), and a main flow channel (40); The formation water channel (20) and the acid channel (30) are arranged side by side and converge to connect with the main channel (40); The advection input device (10) is configured to drive the formation water in the formation water channel (20) or the acid in the acid channel (30) into the main channel (40); The main flow channel (40) is also connected to a core clamping structure, which is configured to fix the sampled core so that formation water or acid entering the main flow channel (40) can flow through the sampled core; the main flow channel (40) is provided with a first three-way connection switch (41), which is located in front of the core clamping structure; The formation water channel (20) and the acid channel (30) are connected to the main channel (40) through the first three-way connection switch (41); the first three-way connection switch (41) is also connected to an inlet pressure gauge (42); The main flow channel (40) is also provided with a second three-way connection switch (43), which is located behind the core clamping structure and is also connected to an outlet pressure gauge (44); the core clamping structure includes a clamp (51) and a ring pressure device (52), the sampled core is placed in the clamp (51) and fixed by the ring pressure device (52); the formation water flow channel (20) is provided with a first intermediate container (21), which contains formation water; The acid flow channel (30) is provided with a second intermediate container (31), which contains acid; the horizontal flow input device (10) includes a first horizontal flow pump (11) and a second horizontal flow pump (12), the first horizontal flow pump (11) is connected to the first intermediate container (21); the second horizontal flow pump (12) is connected to the second intermediate container (31); a solution receiver (45) is connected to the tail of the main flow channel (40); the formation water flow channel (20), the acid flow channel (30) and the main flow channel (40) are all placed in a constant temperature chamber; The specific steps are as follows: Step 1: Before the test begins, check the sealing of each pipeline. The pipeline is made of Hastelloy. Check the connection at the pipeline connection and check the flow control of the horizontal flow input device (10). Step 2: Place the sampled rock core in the nuclear magnetic resonance analysis and imaging system for online detection of physical parameters, and record the detection results R1; Step 3: Close all valves, place the sampled core into the holder (51), fix the sampled core in the holder (51) by the ring clamp (52), connect all pipelines according to the system design drawing, and set the temperature in the constant temperature chamber to the required value; Step 4: Open the first three-way connection switch (41), turn on the first horizontal flow pump (11) to smoothly push the formation water injected in the first intermediate container (21) into the clamp (51), record the data of the inlet pressure gauge (42) and the outlet pressure gauge (44), record the data as F1 when the outlet flow rate is consistent with the inlet flow rate, and then turn off the first horizontal flow pump (11). Step 5: Turn on the second advection pump (12) and smoothly push the acid solution injected in the second intermediate container (31) into the clamp (51). Observe the values ​​displayed by the inlet pressure gauge (42) and the outlet pressure gauge (44); and adjust the flow rate by using the second advection pump (12). Step 6: When the value on the outlet pressure gauge (44) changes significantly, and the unit time flow rate value connected to the solution receiver (45) is the same as the flow rate value set by the second parallel flow pump (12), close the first three-way connection switch (41), close the second parallel flow pump (12), and collect the residual liquid in the solution receiver (45). Step 7: Open the first three-way connection switch (41), turn on the first horizontal flow pump (11) to smoothly push the formation water injected in the first intermediate container (21) into the clamp (51). When the outlet flow rate is consistent with the inlet flow rate, record the data F2 of the inlet pressure gauge (42) and the outlet pressure gauge (44). Turn off the first horizontal flow pump (11) and turn off the constant temperature box. Step 8: Perform online detection of physical parameters on the sampled core after acid displacement using a nuclear magnetic resonance analysis and imaging system, and record the detection results R2; Step 9: Place the sampled core back into the holder (51), keep other conditions unchanged, inject the residual liquid obtained in Step 5 into the second intermediate container (31), turn on the second advection pump (12), and smoothly push the residual liquid in the second intermediate container (31) into the holder (51), and observe the values ​​displayed by the inlet pressure gauge (42) and the outlet pressure gauge (44); Step 10: When the value on the outlet pressure gauge (44) changes significantly, and the unit time flow rate value connected to the solution receiver (45) is the same as the flow rate value set by the second parallel flow pump (12), close the second three-way connection switch, close the first three-way connection switch (41), close the second parallel flow pump (12), and carry out acidification well simmering according to the experimental design time. Step 11: Open the second three-way connection switch, open the first three-way connection switch (41), discharge the residual acid to the solution receiver (45), turn on the first horizontal flow pump (11) to smoothly push the formation water injected in the first intermediate container (21) into the holder (51), record the data F3 of the inlet pressure gauge (42) and the outlet pressure gauge (44) when the outlet flow rate is consistent with the inlet flow rate, turn off the first horizontal flow pump (11), turn off the constant temperature box, and take out the sample core from the holder (51); Step 12: Perform online detection of physical parameters on the core samples taken after the acidizing and simmering experiment using a nuclear magnetic resonance analysis and imaging system, and record the detection results R3; Step 13: Analyze and process the liquid measurement data F1, F2, and F3, analyze the data and images of R1, R2, and R3 obtained from the nuclear magnetic resonance analysis and imaging system, and analyze and compare the data with relevant data from wells that have not undergone acidizing and shut-in experiments.

Images