Underground temperature and pressure monitoring method and temperature and pressure monitoring tool

Abstract

The invention belongs to the field of oil production engineering, and relates to an underground temperature and pressure monitoring method and a temperature and pressure monitoring tool. A monitoring well is selected nearby the target horizontal well or the monitoring well is drilled, perforation operation is carried out on monitoring layers, at different heights, of the monitoring well, a plurality of monitoring devices are conveyed to perforation positions of the monitoring layers of the monitoring well, and the monitoring devices are at least used for monitoring pressure values. And the target horizontal well is fractured, and pressure monitoring data of the target horizontal well in the fracturing process are obtained through the monitoring device. According to the pressure monitoring data, fracturing evaluation data is obtained and used for evaluating the fracturing effect of the target horizontal well, the current state of the target horizontal well is evaluated according to the fracturing evaluation data, and fracture parameters are obtained according to the current state of the target horizontal well and fracturing construction time. According to the method, the fracturing effect of the target horizontal well can be evaluated, the fracture parameters can be obtained according to the current state and the fracturing construction time of the target horizontal well, the measurement mode is simple and efficient, and the result is accurate.

Description

Technical Field

[0001] The present invention belongs to the field of oil production engineering and relates to a downhole temperature and pressure monitoring method and a temperature and pressure monitoring tool. Background Art

[0002] The horizontal well tight cutting fracturing technology has gradually become the main transformation means for shale oil development. To further clarify the fracture propagation pattern and improve the refinement degree of fracture treatment effect evaluation, fracture monitoring needs to be implemented.

[0003] At present, there are two methods for fracture monitoring: near-well monitoring and far-well monitoring. Near-well fracture monitoring includes fiber optic temperature monitoring and acoustic wave monitoring. The liquid injection volume of each cluster of fractures is inferred by the temperature and acoustic wave energy in the near-well zone through these two monitoring methods, and the fracture parameters cannot be directly obtained. Far-well monitoring includes microseismic monitoring, strain fiber optic monitoring, etc. The fracture treatment volume monitored by microseismic is relatively large. Strain fiber optic can evaluate the pressure channeling between clusters and wells, but it cannot monitor the change of fracture height. The above two monitoring methods are not only expensive but also complex to implement. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a downhole temperature and pressure monitoring method and a temperature and pressure monitoring tool. The present invention monitors the pressure change during the fracturing process of the target horizontal well to obtain fracturing evaluation data, and then evaluates the fracturing effect of the target horizontal well. According to the current state of the target horizontal well and the fracturing construction time, fracture parameters can be obtained, and the measurement method is simple and efficient, and the result is accurate.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention discloses a downhole temperature and pressure monitoring method, including the following steps:

[0007] Select a monitoring well near or drill a monitoring well in the target horizontal well, and perform perforation operations on the monitoring horizons at different heights of the monitoring well;

[0008] Transport a plurality of monitoring devices to the perforation positions of the monitoring horizons of the monitoring well;

[0009] Fracture the target horizontal well, and obtain the pressure monitoring data of the target horizontal well during the fracturing process through the monitoring devices;

[0010] According to the pressure monitoring data, obtain fracturing evaluation data, evaluate the current state of the target horizontal well according to the fracturing evaluation data, and obtain fracture parameters according to the current state of the target horizontal well and the fracturing construction time.

[0011] Further, the distance between the monitoring well and the target horizontal well is less than a preset distance range.

[0012] Furthermore, the monitoring device can obtain the temperature monitoring data of the target horizontal well during the fracturing process, and the temperature monitoring data is used to assist the pressure monitoring data to obtain the fracturing evaluation data;

[0013] The fracturing evaluation data includes first state sub-data, second state sub-data, and third state sub-data.

[0014] Furthermore, the process of obtaining the first state sub-data is as follows:

[0015] Obtain the test data of the target horizontal well;

[0016] Analyze the test data using the G-function curve analysis method to obtain the closure pressure data;

[0017] According to the closure pressure data and the pressure monitoring data, obtain the first state sub-data, and the first state sub-data is used to characterize whether the target horizontal well is in a state of hydraulic crossflow at each layer.

[0018] Furthermore, the process of obtaining the second state sub-data is as follows:

[0019] Obtain the pressure sub-data in the monitored layer of the target horizontal well;

[0020] According to the pressure sub-data, obtain the second state sub-data, and the second state sub-data is used to characterize the propagation pattern of the hydraulic fractures of the target horizontal well.

[0021] Furthermore, the process of obtaining the third state sub-data is as follows:

[0022] After a fracturing operation is completed on the target horizontal well, monitor the pressure change during the subsequent operation of the target horizontal well through the monitoring device to obtain the third state sub-data, and the third state sub-data is used to characterize whether the fracture between the target horizontal well and the monitoring well is closed.

[0023] Furthermore, a plurality of monitoring devices are transported to the perforation positions of the monitored layers of the monitoring well, and at least two monitoring devices are transported to each monitored layer.

[0024] Furthermore, the current state of the target horizontal well includes a hydraulic crossflow state, a fluid diffusion state, and a poroelastic effect state;

[0025] The fracture parameters include the change of the fracture along the fracture height, the fracture extension trajectory, the time for the fracture to reach the monitoring well, the fracture closure time, and the temperature and pressure gradients of each formation after fracturing energy supplementation.

[0026] The present invention also discloses a downhole temperature and pressure monitoring tool, including a tubing string, wherein a plurality of monitoring devices are arranged inside the tubing string, and pressure guiding holes are provided on the tubing string section.

[0027] Further, the tubing string includes a second tubing section and several tubing sections. The second tubing section and the several tubing sections are both connected by two first tubing collars and a first packer. The first packer is located between the two first tubing collars. The tubing section includes a first tubing section and a tubing nipple. The first tubing section and the tubing nipple are connected by a second tubing collar. A monitoring device, a power supply, a collection unit, a storage unit, and a monitoring device support cylinder are arranged on the first tubing section. A pressure guiding hole is opened on the first tubing section.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In the method of the present invention, a monitoring well is selected near or drilled in the target horizontal well. Perforation operations are carried out on the monitoring horizons at different heights of the monitoring well. The perforation operations are used to set the monitoring device at the perforated position in the subsequent steps, facilitating the monitoring of the pressure value. Several monitoring devices are conveyed to the perforated positions of the monitoring horizons of the monitoring well. The monitoring device is at least used to monitor the pressure value. The target horizontal well is fractured, and the pressure monitoring data of the target horizontal well during the fracturing process is obtained through the monitoring device. According to the pressure monitoring data, fracturing evaluation data is obtained for evaluating the fracturing effect of the target horizontal well. According to the current state of the target horizontal well and the fracturing construction time, fracture parameters are obtained. By monitoring the pressure change of the target horizontal well during the fracturing process, the present invention obtains the fracturing evaluation data, and then conducts the fracturing effect evaluation of the target horizontal well. According to the current state of the target horizontal well and the fracturing construction time, the fracture parameters can be obtained, and the measurement method is simple and efficient, and the result is accurate.

[0030] The downhole temperature and pressure monitoring tool of the present invention includes a tubing string. Several monitoring devices are arranged inside the tubing string. The monitoring device is used to obtain the pressure monitoring data of the target horizontal well during the fracturing process. A pressure guiding hole is opened on the tubing string. The pressure guiding hole is used to connect the monitoring device with the external space of the special tubing, making the pressure guiding hole the only channel for the monitoring device to contact the outside world, which can protect the monitoring device and is not easily damaged during the process of running into the well and being used. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic flow chart of a horizontal well downhole monitoring method according to an embodiment of the present invention;

[0032] Figure 2 It is a schematic structural diagram of a monitoring supporting tool according to an embodiment of the present invention;

[0033] Figure 3 It is a pressure change diagram of the upper layer during the fracturing process according to an embodiment of the present invention;

[0034] Figure 4 It is a pressure change diagram of the upper layer during the fracturing process according to an embodiment of the present invention;

[0035] Figure 5 This is the pressure change diagram of the lower layer and the lower layer during the fracturing process of an embodiment of the present invention;

[0036] Figure 6 This is the pressure change diagram of each stage during the fracturing process of an embodiment of the present invention.

[0037] Wherein: 1. Ball seat; 2. Fracturing ball; 3. First packer; 4. Tubing nipple; 5. Monitoring device; 6. Power supply; 7. Pressure guiding hole; 8. Acquisition unit; 9. Storage unit; 10. Monitoring device support cylinder; 11. First tubing section; 12. Second packer; 13. First tubing coupling; 14. Second tubing coupling; 15. Second tubing section. Detailed implementation mode

[0038] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0040] The present invention will be further described in detail below with reference to the accompanying drawings:

[0041] See Figure 1 , the present invention discloses a downhole temperature and pressure monitoring method, including the following steps:

[0042] S1. Select a monitoring well near or drill a monitoring well in the target horizontal well, and perform perforation operations on the monitoring horizons at different heights of the monitoring well;

[0043] S2. Transport a plurality of monitoring devices 5 to the perforation positions of the monitoring horizons of the monitoring well;

[0044] Transport several monitoring devices 5 to the perforation positions of the monitoring horizons of the monitoring wells, and at least two monitoring devices 5 are transported to each monitoring horizon.

[0045] S3. Fracture the target horizontal well, and obtain the pressure monitoring data of the target horizontal well during the fracturing process through the monitoring device 5;

[0046] The distance between the monitoring well and the target horizontal well is less than the preset distance range.

[0047] The monitoring device 5 can obtain the temperature monitoring data of the target horizontal well during the fracturing process, and the temperature monitoring data is used to assist the pressure monitoring data to obtain the fracturing evaluation data;

[0048] The fracturing evaluation data includes first state sub-data, second state sub-data, and third state sub-data.

[0049] The process of obtaining the first state sub-data is as follows:

[0050] Obtain the test data of the target horizontal well;

[0051] Analyze the test data by using the G-function curve analysis method to obtain the closed pressure data;

[0052] According to the closed pressure data and the pressure monitoring data, obtain the first state sub-data, and the first state sub-data is used to characterize whether the target horizontal well is in a state of hydraulic channeling at each horizon.

[0053] The process of obtaining the second state sub-data is as follows:

[0054] Obtain the pressure sub-data in the monitoring horizons of the target horizontal well;

[0055] According to the pressure sub-data, obtain the second state sub-data, and the second state sub-data is used to characterize the propagation pattern of the hydraulic fractures of the target horizontal well.

[0056] The process of obtaining the third state sub-data is as follows:

[0057] After a fracturing operation of the target horizontal well is completed, monitor the pressure change situation during the subsequent operation process of the target horizontal well through the monitoring device 5 to obtain the third state sub-data, and the third state sub-data is used to characterize whether the fracture between the target horizontal well and the monitoring well is closed.

[0058] S4. According to the pressure monitoring data, obtain the fracturing evaluation data, evaluate the current state of the target horizontal well according to the fracturing evaluation data, and obtain the fracture parameters according to the current state of the target horizontal well and the fracturing construction time.

[0059] The current state of the target horizontal well includes a hydraulic channeling state, a fluid diffusion state, and a poroelastic effect state;

[0060] The fracture parameters include the variation of the fracture along the fracture height, the fracture extension trajectory, the time for the fracture to reach the monitoring well, the fracture closure time, and the temperature and pressure gradients of each formation after fracturing and energy supplementation.

[0061] See Figure 1 , in another feasible embodiment of the present invention, the following is adaptively modified according to the situation. Select a monitoring well nearby or drill a monitoring well in the target horizontal well, and perform perforation operations on the monitoring layers at different heights of the monitoring well. The perforation operations are used to set the monitoring device at the perforation position in the subsequent steps to facilitate the monitoring of the pressure value. Transport a plurality of monitoring devices 5 to the perforation positions of the monitoring layers of the monitoring well. The monitoring device is at least used to monitor the pressure value. Perform fracturing on the target horizontal well, and obtain the pressure monitoring data of the target horizontal well during the fracturing process through the monitoring device 5. According to the pressure monitoring data, obtain the fracturing evaluation data for evaluating the fracturing effect of the target horizontal well. Evaluate the current state of the target horizontal well according to the fracturing evaluation data, and obtain the fracture parameters according to the current state of the target horizontal well and the fracturing construction time. By comparing the fracturing construction time, the variation of the fracture along the fracture height, the fracture extension trajectory, the time for the fracture to reach the monitoring well, the fracture closure time, the temperature and pressure gradients of each formation after fracturing and energy supplementation, etc. can be obtained. The measurement method is simple and efficient, and the result is accurate.

[0062] Embodiment 1

[0063] This embodiment discloses a downhole monitoring method for a horizontal well, including:

[0064] Step S10, perforate the layers at different heights of the monitoring well, where the distance between the monitoring well and the target horizontal well is less than the preset distance range.

[0065] In this embodiment, in step S10, first select or drill a vertical well or a directional well as the monitoring well near the target horizontal well, and then perform perforation operations on the layers at different heights of the monitoring well. The perforation operations are used to set the monitoring device at the perforation position in the subsequent steps for at least monitoring the pressure value. Among them, the preset distance range is the designed fracture half-length, and the specific distance between the monitoring well and the target horizontal well is not limited and can be reasonably selected according to actual application requirements. For example, it can be selected within the range of 50 meters, 100 meters, and 150 meters near the target horizontal well. Perform perforation operations on the layers at different vertical depths of the vertical well for monitoring the layers at different heights of the vertical section in the subsequent steps, and the obtained data is more comprehensive.

[0066] Optionally, the position distance between the monitoring well and the target horizontal well is preferably 50 meters - 150 meters, so that the data of the monitoring well can be closer to the data of the target well, and at the same time, it can ensure that the monitoring well monitors effective data. If the distance is too far, the monitoring device may not respond.

[0067] Step S20: Transport multiple monitoring devices to multiple monitoring horizons of the monitoring well, where the monitoring device is at least used to monitor the pressure value.

[0068] In this embodiment, in step S20, load multiple monitoring devices into a special oil pipe and transport them to multiple monitoring horizons of the monitoring well, where the monitoring device is at least used to monitor the pressure value; in addition, number the monitoring devices, record the planned setting depth, the battery installation time, and determine its effective working time.

[0069] Optionally, transporting multiple monitoring devices to multiple monitoring horizons of the monitoring well includes: using a special oil pipe to transport the monitoring devices to multiple monitoring horizons of the monitoring well, where the monitoring device is located in the special oil pipe, and the special oil pipe is provided with pressure guiding holes for communicating the monitoring device with the external space of the special oil pipe.

[0070] Among them, the structure of the special oil pipe carrying multiple monitoring devices is mainly that pressure guiding holes are provided on the surface of the special oil pipe, the monitoring device is arranged inside the special oil pipe, and the special oil pipe and the ordinary oil pipe are combined into the whole pipe string. After being lowered into the formation, the monitoring device transmits pressure through the pressure guiding holes, making the pressure guiding holes the only channel for the monitoring device to contact the outside world, which can protect the monitoring device and is not easily damaged during the process of being lowered into the well and in use.

[0071] Step S30: Use the monitoring device to monitor the pressure change of the target horizontal well during the fracturing process and obtain pressure monitoring data.

[0072] In this embodiment, in step S30, during the fracturing process of the target well, the monitoring device in the monitoring well monitors to obtain pressure monitoring data. After the fracturing is completed, lift the pipe string to release the packer, and take out all the monitoring devices according to the serial numbers to read the pressure monitoring data at different times.

[0073] Optionally, the packer can be a hydraulic type non-slip packer, which is set by pumping pressure and can effectively isolate the annulus between the casing and the tubing. After the monitoring is completed, lifting the pipe string will cut the pin of the lower joint to complete automatic release. The packer mainly plays a role in isolating the pressure gauges of different horizons to ensure accurate measurement of the pressure and temperature of each layer.

[0074] Step S40: Obtain fracturing evaluation data according to the pressure monitoring data, where the fracturing evaluation data is at least used to evaluate whether the target horizontal well is in a state of hydraulic crossflow.

[0075] In this embodiment, in step S40, compare with the fracturing construction time and analyze the fracturing evaluation data of the fracture to evaluate whether the target horizontal well is in a state of hydraulic crossflow.

[0076] Optionally, the monitoring device is also used to monitor the temperature value; monitor the temperature change of the target horizontal well during the fracturing process by using the monitoring device to obtain temperature monitoring data; correspondingly, according to the pressure monitoring data, the obtained fracturing evaluation data includes: obtaining the fracturing evaluation data according to the pressure monitoring data and the temperature monitoring data.

[0077] Among them, the monitoring device can also be used to monitor the temperature change of the target horizontal well during the fracturing process to obtain temperature monitoring data; correspondingly, according to the pressure monitoring data and the temperature monitoring data, the fracturing evaluation data is obtained to evaluate whether the target horizontal well is in a state of hydraulic communication. Since the pressure diffusion rate is much greater than the temperature diffusion rate, generally, the temperature change will only occur when the fracturing fluid is in direct contact with the monitoring device, but the pressure value can change without direct contact due to the conduction of waves. By combining the pressure monitoring data and the temperature monitoring data, the evaluation angle is more comprehensive, and they can be corrected with each other, enabling a more accurate evaluation of the fracturing effect of the target horizontal well.

[0078] Furthermore, the fracturing evaluation data includes first state sub-data, and the first state sub-data is used to characterize whether the target horizontal well is in a state of hydraulic communication at each layer; correspondingly, according to the pressure monitoring data, the obtained fracturing evaluation data includes: obtaining the first state sub-data according to the closure pressure data corresponding to the target horizontal well and the pressure monitoring data.

[0079] Among them, according to the closure pressure data corresponding to the target horizontal well and the pressure monitoring data, the first state sub-data is obtained, and the first state sub-data is used to characterize whether the target horizontal well is in a state of hydraulic communication at each layer.

[0080] Among them, the closure pressure data is a value obtained by calculation in advance. If the pressure monitoring data is greater than the closure pressure data, it indicates that hydraulic communication has occurred.

[0081] Among them, the shape of the pressure monitoring data response curve of the monitoring well monitoring device can reflect the state of the fracturing cracks of the target horizontal well at each layer. When hydraulic communication occurs, the pressure monitoring data response curve shows that the pressure monitoring data rapidly increases to the peak value, and the fracturing process is above the closure pressure data; when the poroelastic effect occurs, the pressure monitoring data response curve shows that the pressure monitoring data gradually increases, and the pressure monitoring data is always lower than the closure pressure data; during fluid diffusion, the pressure monitoring data response curve has no obvious inflection point, and the pressure monitoring data continues to rise after the fracturing ends until it reaches equilibrium.

[0082] Optionally, a plurality of monitoring devices are transported to a plurality of monitoring horizons of a monitoring well, and at least two monitoring devices are transported to at least one target horizon, where the target horizon is one of the plurality of monitoring horizons; correspondingly, the pressure change of the target horizontal well during the fracturing process is monitored by the monitoring devices, and the obtained pressure monitoring data includes: monitoring the pressure change of the target horizontal well during the fracturing process by at least two monitoring devices in the target horizon to obtain first monitoring sub-data and second monitoring sub-data; and obtaining the pressure monitoring data according to the first monitoring sub-data and the second monitoring sub-data.

[0083] Among them, at least one target horizon is selected from the plurality of monitoring horizons, at least two monitoring devices are transported to the target horizon, and the pressure change of the target horizontal well during the fracturing process is monitored by at least two monitoring devices in the target horizon to obtain first monitoring sub-data and second monitoring sub-data; the pressure monitoring data is obtained through the first monitoring sub-data and the second monitoring sub-data. By using at least two monitoring devices, the function of data backup can be achieved to prevent data loss when one of the monitoring devices is damaged; in addition, the measurement results can be made more accurate.

[0084] Optionally, the fracturing evaluation data includes first status sub-data, and the first status sub-data is used to characterize whether the target horizontal well is in a state of hydraulic crossflow in each horizon; correspondingly, obtaining the fracturing evaluation data according to the pressure monitoring data includes: obtaining the first status sub-data according to the closure pressure data and the pressure monitoring data corresponding to the target horizontal well.

[0085] Among them, the first status sub-data is obtained according to the temperature monitoring data, the fracturing evaluation data includes the first status sub-data, and the first status sub-data is used to characterize the state of the fracturing cracks of the target horizontal well in each horizon.

[0086] Among them, the state of the target horizontal well in each horizon can generally be divided into three types: hydraulic crossflow state, fluid diffusion state, and poroelastic effect. If the first status sub-data drops suddenly at a certain moment, it indicates that hydraulic crossflow occurs; if the first status sub-data remains unchanged all the time, it indicates that poroelastic effect or fluid diffusion occurs.

[0087] Furthermore, the method of the present invention further includes: performing a mini-fracture test on the target horizontal well to obtain test data corresponding to the target horizontal well; and analyzing the test data corresponding to the target horizontal well by using the G-function curve analysis method to obtain the closure pressure data corresponding to the target horizontal well.

[0088] Among them, the method for obtaining the closure pressure data corresponding to the target horizontal well further included in the method can be to perform a mini-fracture test on the target horizontal well and analyze the test data corresponding to the target horizontal well by using the G-function curve analysis method.

[0089] Among them, if a mini-frac test is carried out on the target horizontal well, the closure pressure can be analyzed and obtained by using the G-function curve analysis method, and the closure pressure data can be accurately obtained.

[0090] Furthermore, the method further includes: obtaining the closure pressure data corresponding to the target horizontal well according to the closure pressure data corresponding to at least one adjacent well; wherein, the adjacent well is a horizontal well located in the same block as the target horizontal well.

[0091] Among them, the method further includes a method for obtaining the closure pressure data corresponding to the target horizontal well. The closure pressure data corresponding to the target horizontal well is obtained according to the closure pressure data corresponding to at least one adjacent well located in the same block as the target horizontal well.

[0092] Among them, if a mini-frac test is not carried out on the target horizontal well, the closure pressure data of the target horizontal well is converted according to the fracture closure pressure gradient analyzed by the mini-frac test of the adjacent well in the same block. In this way, the construction cost can be lower while ensuring the accuracy of the closure pressure data.

[0093] Optionally, the frac evaluation data includes second state sub-data, and the second state sub-data is used to characterize the propagation pattern of the hydraulic fracture of the target horizontal well; correspondingly, obtaining the frac evaluation data according to the pressure monitoring data includes: obtaining the corresponding pressure sub-data in multiple target horizons, wherein the target horizon is one of multiple monitored horizons, and the pressure sub-data is generated according to the monitoring results of the monitoring device located in the target horizon during the fracturing process of the target horizontal well; obtaining the second state sub-data according to the corresponding pressure sub-data in multiple target horizons.

[0094] Among them, the propagation pattern of the hydraulic fracture includes the change in the height of the fracture, the fracture extension trajectory, the extension distance of the fracture along the fracture height direction, the time for the fracture to reach the monitoring well, the fracture closure time, the temperature and pressure gradients of each formation after frac energy supplementation, etc.

[0095] Among them, one of the multiple monitored horizons is selected as the target horizon, and the corresponding pressure sub-data in multiple target horizons is obtained according to the monitoring results of the monitoring device located in the target horizon during the fracturing process of the target horizontal well; the second state sub-data is obtained according to the corresponding pressure sub-data in multiple target horizons, and the second state sub-data can be used to characterize the propagation pattern of the hydraulic fracture of the target horizontal well. By processing the multiple pressure sub-data of multiple target horizons at different heights in the monitored vertical well section, the second state sub-data of the hydraulic fracture corresponding to multiple target horizons can be obtained, and the fracture propagation pattern can be judged more accurately and directly.

[0096] Optionally, the method of the present invention further includes: the fracturing evaluation data includes third state sub-data, and the third state sub-data is used to characterize whether the fracture between the target horizontal well and the monitoring well is closed; correspondingly, a monitoring device is used to monitor the pressure change of the target horizontal well during the fracturing process, and the obtained pressure monitoring data includes: after the target horizontal well completes a fracturing operation, the monitoring device monitors the pressure change of the target horizontal well during the subsequent operation process to obtain the third state sub-data.

[0097] Among them, the method further includes a method for judging whether the fracture between the target horizontal well and the monitoring well is closed. The pressure change of the target horizontal well during the fracturing process can be monitored by a monitoring device, and the obtained pressure monitoring data includes: after the target horizontal well completes a fracturing operation, the monitoring device monitors the pressure change of the target horizontal well during the subsequent operation process to obtain the third state sub-data, and judges whether the fracture between the target horizontal well and the monitoring well is closed according to the third state sub-data.

[0098] Among them, if a fracturing channeling phenomenon occurs in the previous stage of fracturing, through subsequent operations, such as perforating guns, pumping in bridge plugs, etc., the fracture closing time can be determined. If an immediate pressure response is observed in the monitoring well, it indicates that the fracture that has channeled to the monitoring well is not closed and is still directly connected to the fracturing well, so that the operation of the horizontal well can be continuously monitored.

[0099] As can be seen from the above embodiments, perforate different layers of the monitoring well whose distance from the target horizontal well is less than the preset distance range, and transport multiple monitoring devices to multiple monitoring layers of the monitoring well. Among them, the monitoring device is at least used to monitor the pressure value; use the monitoring device to monitor the pressure change of the target horizontal well during the fracturing process to obtain pressure monitoring data; according to the pressure monitoring data, obtain fracturing evaluation data for evaluating the fracturing effect of the target horizontal well; by comparing the fracturing construction time, the change of the fracture along the fracture height, the fracture extension trajectory, the time for the fracture to reach the monitoring well, the fracture closing time, the temperature and pressure gradients of each layer series after fracturing energy supplementation, etc. can be obtained. The measurement method is simple and efficient, and the results are accurate.

[0100] Embodiment 2:

[0101] This embodiment provides a downhole temperature and pressure monitoring method, including the following specific steps:

[0102] Step 1: Select the target horizontal well H1 with a vertical depth of 3005m, the completed drilling horizon is the Chang 71 formation, the formation pressure is 15.8MPa, the formation temperature is 57.2°C, where the horizontal section is 1300m long and the vertical depth is 1705m; the horizontal well H2 and H1 are located on the same platform, select the horizontal well H2 as the microseismic monitoring well of the H1 well, the well distance between the two wells is 250m, drill a monitoring well at the middle position between the H1 and H2 wells, and use casing completion.

[0103] Step 2: Number the 8 monitoring devices 1-8 respectively, divide the strata into upper layer, upper-middle layer, lower-middle layer and lower layer, and divide the 8 monitoring devices into 4 groups. Place monitoring devices 1 and 2 on the top layer, monitoring devices 3 and 4 on the upper-middle layer, monitoring devices 5 and 6 on the lower-middle layer, and monitoring devices 7 and 8 on the bottom layer. Two monitoring devices in a group can serve as backup and comparison to ensure the validity of the data, and then record their respective descent depths, battery installation time, effective working time, etc.

[0104] First, place the monitoring device in the tubing. The two sides of the tubing where the monitoring device is located are separated by a packer. Then, connect the pressure gauge to the tubing and the tubing nipple and lower it into the corresponding perforation position. The specific connection conditions are as follows: Figure 2 As shown in the figure, after the tubing is lowered, the depth is calibrated by logging to ensure that the pressure gauge is at the perforation layer.

[0105] Step 3: The microseismic monitoring well H2 cooperates with the target well H1 to carry out fracturing construction. After the fracturing is completed, the lifting pipe string will cut the packer pin, causing the packer rubber cylinder to retract to achieve unsealing. The monitoring devices are taken out one by one in sequence to read the second-point pressure and temperature data. The scope of crack transformation and pressure channeling are determined according to the fracturing time, and the microseismic results are corrected.

[0106] Step 4: According to the data analysis results of the monitoring device: Among the monitoring devices No. 1-8, the two monitoring devices at the same layer read the same data, indicating that the data is valid and reliable, so one of the monitoring devices No. 1, 3, 5, and 7 at the same layer is taken for analysis. After the monitoring device is installed on the ground, the monitoring device is lowered into the formation with the pipe string, and the pressure setting of the packer is completed, which takes a total of 26 hours. During the packer setting process, the pressure gauge shows a pressure fluctuation and rising form. 42 hours after the monitoring device is lowered, the H1 well starts the fracturing operation, the 6th section, the monitoring range of the monitoring well in this embodiment is the 6th-8th section of the horizontal fracturing well, the 6th section is the first section to start monitoring, and after monitoring the 8th section, the monitoring ends and the pressure gauge is raised to the wellhead.

[0107] According to the results of the small-scale fracturing test, the closure stress gradient of the H1 well is 0.0140MPa / m, so the closure pressures of the four layers from top to bottom are 23.7MPa, 24.1MPa, 24.6MPa, and 24.8MPa, respectively. From the pressure response, it can be seen that the pressure in the downhole monitoring device of each layer is always less than the closure pressure of each layer, indicating that no hydraulic interference occurs. On the other hand, the temperature during the fracturing process remains unchanged, which also indicates that no hydraulic interference occurs.

[0108] By comparing the pressure changes between layers, it is found that the pressure response amplitude of monitoring devices No. 3, 5, and 7 in sections 6 and 7 is relatively high, and then the overall pressure shows: No. 5 ≈ No. 7> No. 3> No. 1, such as Figure 3 , Figure 4 ,Figure 5 As shown, it indicates that during the fracturing of the 6th and 7th stages, the fractures mainly extend in Chang 71, and during the 8th - 17th stages, the fractures mainly extend within Chang 71 and Chang 72. Combining with the geological modeling results, it is found that the thickness of the mudstone at the bottom of the Chang 71 layer decreases after the 8th stage, resulting in the fractures extending to the Chang 72 layer.

[0109] Comparing the pressure responses of each stage, as Figure 6 shown, it is found that the pressure change amplitudes of the 6th, 7th, and 8th stages are the largest. Generally, the closer the distance between the fractures of the fracturing well and the monitoring well, the higher the pressure response amplitude and the later the pressure response. The reason is that the distance between the monitoring well V1 and the target well H1 at the 6th, 7th, and 8th stages is relatively close. In addition, the monitoring well is located in the middle of the 7th and 8th stages, but the response of the monitoring device in the middle and upper layers of the 6th stage is the most obvious. It may be because during the fracturing of the 6th stage, the fractures encounter natural fractures during the upward extension, causing the pressure of the No. 3 monitoring device to change violently, which also indicates that the fractures extend to the middle and upper layers. As Figure 3 , Figure 4 , Figure 5 shown, it can be seen that the responses of the No. 5 and 7 monitoring devices are almost the same, indicating that the fractures do not extend to the middle and lower layers. Therefore, the fracture height is less than 34m. Compared with the fracture height of 43m in the microseismic interpretation result, the fracture height in the microseismic interpretation is on the high side. The distance between the monitoring well and the fracturing well is 125m, so the fracture half - length is greater than 125m, which is consistent with the microseismic fracture length. Therefore, this method can be used to verify the microseismic interpretation results.

[0110] In addition, through the monitoring device, the temperature and pressure gradients of each layer after the fracturing energy supplementation can also be measured. After setting the packer, the recorded pressures of the No. 3, 5, and 7 monitoring devices show an upward trend, and the pressure at the end of the test is 20.30MPa - 20.85MPa. Therefore, the pressure coefficient of the Chang 7 layer near Well H1 after fracturing is about 1.17. The test pressure of the No. 1 monitoring device first rises and then falls, and the later test pressure is basically stable at 17.55MPa. Therefore, the pressure coefficient of the Chang 6 layer near Well H1 is 1.04. After calculation, the temperature gradients of both the Chang 6 and Chang 7 layers are 3.34 / 100m.

[0111] Referring to Figure 2 , the present invention also discloses a downhole temperature and pressure monitoring tool for monitoring downhole temperature and pressure, including a tubing string. A number of monitoring devices 5 are arranged inside the tubing string. The monitoring device 5 is used to obtain the pressure monitoring data of the target horizontal well during the fracturing process. A pressure guiding hole 7 is opened on the tubing string. The pressure guiding hole 7 is used to connect the monitoring device with the external space of the special tubing string, making the pressure guiding hole the only channel for the monitoring device to contact the outside world. In this way, the monitoring device can be protected and is not easily damaged during the process of running into the well and being used.

[0112] Example 3:

[0113] Referring to Figure 2This embodiment discloses a downhole temperature and pressure monitoring tool, including an oil pipe, in which a plurality of monitoring devices 5 are arranged, and a pressure guide hole 7 is opened on the oil pipe.

[0114] The oil pipe includes a second oil pipe section 15 and several oil pipe sections, which are all connected to the first packer 3 through two first oil pipe couplings 13, and the first packer 3 is located between the two first oil pipe couplings 13. The oil pipe section includes a first oil pipe section 11 and an oil pipe nipple 4, which are connected to the oil pipe nipple 4 through a second oil pipe coupling 14. The first oil pipe section 11 is provided with a monitoring device 5, a power supply 6, a collection unit 8, a storage unit 9 and a monitoring device support 10, and a pressure guide hole 7 is provided on the first oil pipe section 11. The power supply has the ability to ensure that the pressure gauge can work continuously for several days underground, the collection module has the ability to collect second-point pressure and temperature data in real time, and the storage module can store all second-point pressure and temperature data recorded in the power-on state. After the data collection is completed, the pressure and temperature data can be read by connecting to a computer for later data analysis, and data loss will not occur when the power is cut off.

[0115] Preferably, the packer can be a hydraulic slip-free packer, which can effectively seal the casing annulus by pressurizing and setting the seal. After the monitoring is completed, the pipe string will be lifted to cut the pin of the lower joint to complete the automatic release. The packer mainly seals the pressure gauges at different layers to ensure accurate pressure and temperature measurement of each layer.

[0116] The present invention perforates different layers of a monitoring well whose distance from a target horizontal well is less than a preset distance range, and transports multiple monitoring devices to multiple monitoring layers of the monitoring well, wherein the monitoring devices are at least used to monitor pressure values; the monitoring devices are used to monitor pressure changes in the target horizontal well during the fracturing process to obtain pressure monitoring data; based on the pressure monitoring data, fracturing evaluation data is obtained to evaluate the fracturing effect of the target horizontal well; by comparing the fracturing construction time, the change in crack height along the crack, the crack extension trajectory, the time when the crack arrives at the monitoring well, the crack closure time, the temperature and pressure gradient of each layer after fracturing energy replenishment, etc. can be obtained, and the monitoring method is simple and efficient, and the results are accurate.

[0117] The above contents are only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A downhole temperature and pressure monitoring method, characterized in that, It includes the following steps: Select a monitoring well near or drill a monitoring well in the target horizontal well, and perform perforation operations on the monitoring horizons at different heights of the monitoring well; Transport a number of monitoring devices (5) to the perforation positions of the monitoring horizons of the monitoring well; Fracture the target horizontal well, and obtain the pressure monitoring data of the target horizontal well during the fracturing process through the monitoring device (5); According to the pressure monitoring data, obtain the fracture evaluation data, evaluate the current state of the target horizontal well according to the fracture evaluation data, and obtain the fracture parameters according to the current state of the target horizontal well and the fracturing construction time.

2. The downhole temperature and pressure monitoring method according to claim 1, wherein The distance between the monitoring well and the target horizontal well is less than the preset distance range.

3. The downhole temperature and pressure monitoring method according to claim 1, characterized in that The monitoring device (5) can obtain the temperature monitoring data of the target horizontal well during the fracturing process, and the temperature monitoring data is used to assist the pressure monitoring data to obtain the fracture evaluation data; The fracture evaluation data includes a first state sub-data, a second state sub-data, and a third state sub-data.

4. The downhole temperature and pressure monitoring method according to claim 3, wherein The process of obtaining the first state sub-data is as follows: Obtain the test data of the target horizontal well; Analyze the test data by using the G-function curve analysis method to obtain the closure pressure data; According to the closure pressure data and the pressure monitoring data, obtain the first state sub-data, and the first state sub-data is used to characterize whether the target horizontal well is in a state of hydraulic crossflow at each horizon.

5. The downhole temperature and pressure monitoring method according to claim 3, characterized in that The process of obtaining the second state sub-data is as follows: Obtain the pressure sub-data in the monitoring horizons of the target horizontal well; According to the pressure sub-data, obtain the second state sub-data, and the second state sub-data is used to characterize the propagation pattern of the hydraulic fractures of the target horizontal well.

6. The downhole temperature and pressure monitoring method according to claim 3, wherein, The process of obtaining the third state sub-data is as follows: After a fracturing operation is completed on the target horizontal well, monitor the pressure change situation during the subsequent operation of the target horizontal well through the monitoring device (5) to obtain the third state sub-data, and the third state sub-data is used to characterize whether the fracture between the target horizontal well and the monitoring well is closed.

7. The downhole temperature and pressure monitoring method according to claim 1, characterized in that, When transporting a number of monitoring devices (5) to the perforation positions of the monitoring horizons of the monitoring well, at least two monitoring devices (5) are transported to each monitoring horizon.

8. The downhole temperature and pressure monitoring method according to claim 1, characterized in that, The current state of the target horizontal well includes a hydraulic crossflow state, a fluid diffusion state, and a poroelastic effect state; The fracture parameters include the change of the fracture along the fracture height, the fracture extension trajectory, the time for the fracture to reach the monitoring well, the fracture closure time, and the temperature and pressure gradients of each formation after fracture energy supplementation.

9. An underground temperature and pressure monitoring tool, characterized in that, It includes a tubing string, and a number of monitoring devices (5) as described in any one of claims 1 to 8 are arranged inside the tubing string, and pressure guiding holes (7) are opened on the tubing string.

10. A downhole temperature and pressure monitoring tool as claimed in claim 9, characterized in that, The tubing string includes a second tubing section (15) and several tubing sections. The second tubing section (15) and the several tubing sections are all connected by two first tubing collars (13) and a first packer (3). The first packer (3) is located between the two first tubing collars (13). The tubing section includes a first tubing section (11) and a tubing nipple (4). The first tubing section (11) and the tubing nipple (4) are connected by a second tubing collar (14). A monitoring device (5), a power supply (6), a collection unit (8), a storage unit (9) and a monitoring device support cylinder (10) are arranged on the first tubing section (11). A pressure guiding hole (7) is provided on the first tubing section (11).

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