DTS correction device and method based on multi-point capsule pressure gauge

Abstract

A DTS correction device and method based on multi-point capsule pressure gauges, the correction device comprises an optical cable lowered into a well along a casing, a plurality of point measuring capsule pressure gauges are arranged on the optical cable corresponding to different reservoir heights, the depths of the point measuring capsule pressure gauges are determined through thermal marking, a DTS correction relationship at different depths and different times downhole is established by using the relationship between the temperature at the depth of the point measuring capsule pressure gauges and the temperature at the corresponding depth of the DTS changing with time, and the DTS is temperature corrected according to the DTS correction relationship. For the oil-water well with large inclination change, the actual refractive index of the optical fiber is greatly affected by the well inclination, the optical fiber DTS logging accuracy is low, and the stability is poor, in order to obtain the real DTS temperature response characteristics of the wellbore, a plurality of point measuring capsule pressure gauges are added on the optical cable, a multi-point calibration combined with a continuous curve calibration method is adopted, the data information is enriched, and the temperature drift correction reference point is changed from the original single point to the whole well section.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of oil exploration and development, and relates to a DTS correction device and method based on a multi-point capsule pressure gauge. BACKGROUND

[0002] With the deepening of exploration and development, horizontal well staged fracturing technology has been widely used in various oilfields to improve single well production, but there has been a lack of effective means for dynamic monitoring and evaluation of horizontal well productivity. In recent years, distributed optical fiber logging (DTS / DAS) technology has attracted widespread attention from users due to its small size, light weight, anti-vibration, anti-interference, low power consumption, high sensitivity, ultra-high temperature and pressure resistance, and other advantages. Its application, application scenarios and application scale are constantly expanding, such as shale oil and gas horizontal well dynamic production monitoring, fracturing monitoring, water plugging guidance, etc. The rapid development of distributed optical fiber logging dynamic monitoring technology makes it possible to monitor and evaluate horizontal well staged fracturing, and it is expected to become a powerful tool for guiding production logging to move towards the middle and high end. At the same time, the fluctuation of the excitation light source, the unreasonable setting of the refractive index, the cable in the drum and the stretching state, the temperature and pressure environment, etc. affect the DTS logging, resulting in temperature drift, affecting the quality of DTS data, and limiting the further development of optical fiber logging. When existing optical fiber logging is performed, a storage type temperature and pressure gauge is simultaneously lowered to the bottom of the optical fiber to realize full-range monitoring of the bottom hole temperature and pressure data, and the bottom hole temperature data monitored thereby are used as a reference to correct the overall DTS temperature; this method can have certain effect in straight wells and absolute horizontal wells, but due to the fact that the actual refractive index of the optical fiber is greatly affected by the inclination, the application effect in oil and water wells with large inclination changes is generally poor, so there is an urgent need to develop a new temperature drift correction method to solve the technical bottleneck problems of low precision and poor stability of optical fiber DTS logging. SUMMARY

[0003] The purpose of the present application is to provide a DTS correction device and method based on a multi-point capsule pressure gauge to solve the problems in the prior art. The present application monitors by arranging multiple point measurement capsule pressure gauges on the cable, establishes a correction relationship chart between the DTS monitoring temperature and the pressure gauge monitoring temperature of each monitoring point by combining the multi-point scale and the linear interpolation method, realizes the DTS correction amount between the pressure gauges by using the linear interpolation method, and finally realizes the fine correction of the whole well section DTS.

[0004] In order to achieve the above purpose, the present application has the following technical solutions:

[0005] The application discloses a DTS correction device based on multi-point capsule pressure gauges, which comprises an optical cable lowered into a well along a casing, wherein a plurality of point measuring capsule pressure gauges are arranged on the optical cable at different heights corresponding to different reservoirs, the depths of the point measuring capsule pressure gauges are determined by heat marking, and the DTS correction relationship at different depths and different times in the well is established by using the time-varying relationship between the temperature at the depth of the point measuring capsule pressure gauges and the temperature at the corresponding depth of the DTS, and the DTS is temperature corrected according to the DTS correction relationship.

[0006] Preferably, the point measuring capsule pressure gauges are in a hollow annular conical structure and are fixed to the outside of the optical cable.

[0007] Preferably, one point measuring capsule pressure gauge is fixed to the optical cable every 200 m.

[0008] Preferably, the point measuring capsule pressure gauges are powered by batteries and can continuously monitor for 50 h.

[0009] Preferably, the optical cable is vertically lowered into the well along the casing, and a counterweight is arranged at the bottom of the optical cable.

[0010] Preferably, the optical cable is connected to an optical fiber monitoring system and an optical fiber depth system, the optical fiber monitoring system is turned on, the optical cable at the positions of the fixed point measuring capsule pressure gauges is heat marked in sequence, and the positions of the point measuring capsule pressure gauges on the optical fiber depth system are determined.

[0011] A DTS correction method based on multi-point capsule pressure gauges comprises the following steps.

[0012] The point measuring capsule pressure gauges on the optical cable are heat marked in sequence, and the positions of the point measuring capsule pressure gauges are determined.

[0013] During the process that the optical cable is lowered into the well along the casing, the speed, temperature and pressure data and the DTS data are recorded.

[0014] After the optical cable is lowered to the bottom of the well along the casing, the DTS and point measuring capsule pressure gauge data under different working systems are recorded.

[0015] The optical cable is pulled up along the casing, and the speed, temperature and pressure data and the DTS data are recorded during the pulling-up process.

[0016] After the test is completed, the point measuring capsule pressure gauge, DTS and wellhead speed data are read, and the temperature data of the point measuring capsule pressure gauges are converted into time-depth.

[0017] The measured temperature curve of the point measuring capsule pressure gauges is compared with the DTS curve at the corresponding time, and the relative correction relationship between the DTS temperature and the capsule temperature of different point measuring capsule pressure gauges is established.

[0018] The temperature correction relationship of the position where each point measuring capsule pressure gauge is located is established by using the time-varying relationship between the temperature and the depth temperature corresponding to the DTS of each point measuring capsule pressure gauge position.

[0019] In combination with the above data, the DTS correction relationship at different depths and different times is established to correct the temperature of the DTS.

[0020] As a preferred scheme, the step of sequentially heat marking the point measuring capsule pressure gauges on the optical cable to determine the positions where the point measuring capsule pressure gauges are located is performed before the optical cable is lowered into the well, the optical fiber monitoring system is started, the point measuring capsule pressure gauges on the optical cable are sequentially heat marked to determine the positions where the point measuring capsule pressure gauges on the optical fiber depth system are located, and the positions where the point measuring capsule pressure gauges are located are determined according to the temperature peak of the heat marked position.

[0021] As a preferred scheme, the point measuring capsule pressure gauge is in a hollow ring-shaped conical structure, is fixed on the outside of the optical cable every 200 meters, and is powered by a battery, and the continuous monitoring duration can reach 50 hours.

[0022] As a preferred scheme, a counterweight is arranged at the bottom of the optical cable, so that the optical cable can be vertically lowered into the well along the casing.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] For the oil-water well with large inclination change, the actual refractive index of the optical fiber is greatly affected by the well inclination, the optical fiber DTS logging accuracy is low, and the stability is poor, in order to obtain the real DTS temperature response characteristics of the wellbore, a plurality of point measuring capsule pressure gauges are arranged on the optical cable, a full-time domain and full-depth domain optical fiber DLC temperature correction method is established by using the measured data, and the DTS multi-point accurate calibration is realized. At present, the optical fiber refractive index is greatly affected by the bending degree of the optical cable, and the bending degree of the optical cable and the existing inclination cannot establish a clear influence relationship, the optical fiber refractive index parameter in the existing acquisition software can only be set as a fixed value, and the unreasonable setting of the refractive index restricts the DTS data acquisition accuracy; in addition, the optical cable is affected by the temperature and pressure of the wellbore environment, and a certain change will occur in the fiber layer, so that the DTS monitoring temperature value will produce different offsets under different temperature and pressure environments. The present application increases a plurality of point measuring capsule pressure gauges on the optical cable, enriches the acquisition data information by using the multi-point calibration combined with the continuous curve calibration method, and realizes that the temperature drift correction reference point changes from the original single point to the whole well section. The present application can effectively solve the technical bottleneck problems of low optical fiber DTS logging accuracy and poor measurement stability, and lay a foundation for promoting the scale application of optical fiber logging in each oilfield. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and other related drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0026] Figure 1 The embodiment of the present application is based on the DTS correction method flowchart of the multi-point capsule pressure gauge.

[0027] Figure 2 The embodiment of the present application is based on the DTS correction device structure diagram of the multi-point capsule pressure gauge.

[0028] Figure 3 The embodiment of the present application is based on the optical cable thermal marking diagram.

[0029] Figure 4 The embodiment of the present application is based on the speed measurement data statistical diagram.

[0030] Figure 5 The embodiment of the present application is based on the test data statistical diagram of the point measurement capsule pressure gauge.

[0031] Figure 6 The embodiment of the present application is based on the optical fiber logging data collection statistical diagram.

[0032] Figure 7 The embodiment of the present application is based on the temperature and adjacent DTS curve comparison curve diagram of the point measurement capsule pressure gauge after the time-depth conversion.

[0033] Figure 8 The embodiment of the present application is based on the temperature and DTS temperature comparison curve diagram of the point measurement capsule pressure gauge with time.

[0034] Figure 9 The embodiment of the present application is based on the waterfall diagram of the DTS correction of well 2-X.

[0035] Figure 10 The embodiment of the present application is based on the waterfall diagram of the DTS correction of well 2-X. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, other embodiments can also be obtained by those skilled in the art without creative labor.

[0037] In order to obtain the real DTS temperature response characteristics of the wellbore, the application provides a DTS correction device and method based on a multi-point capsule pressure gauge, a plurality of point measurement capsule pressure gauges are arranged on the optical cable, a full time domain and full depth domain optical fiber DLC temperature correction method is established by using the data, and multi-point accurate calibration of DTS is realized. At present, the optical fiber refractive index is greatly affected by the bending degree of the optical cable, and the bending degree of the optical cable cannot establish a clear influence relationship with the existing well inclination. In the existing acquisition software, the optical fiber refractive index parameter can only be set as a fixed value, and the unreasonable setting of the refractive index restricts the accuracy of the DTS data acquisition. In addition, the optical cable is affected by the temperature and pressure of the well hole environment, and changes will occur in the fiber layer, so that the DTS monitoring temperature value will produce different offsets under different temperature and pressure environments. The application can effectively solve the above technical problems.

[0038] As shown in Figure 1 The DTS correction method based on the multi-point capsule pressure gauge in the embodiment of the application designs an optical cable with a point measurement capsule pressure gauge; the positions of the capsules are determined by using a thermal marking method; the related data of the capsule pressure gauges, DTS and speed measurement during the lowering, bottom and lifting processes are measured and recorded; the temperature data of the capsule pressure gauges are converted in time and depth; finally, the DTS point measurement curve correction relationship is established; the DTS continuous time domain curve correction relationship is established, and the DTS continuous curve correction is completed.

[0039] As shown in Figure 2 The DTS correction device based on the multi-point capsule pressure gauge in the embodiment of the application comprises an optical cable 2 lowered into the well along a casing 5, a plurality of point measurement capsule pressure gauges 3 arranged on the optical cable 2 corresponding to the heights of different reservoirs 6, and a counterweight 4 arranged at the bottom of the optical cable 2. The depths of the point measurement capsule pressure gauges 3 are determined by using a thermal marking method, and the temperature correction relationship of DTS at different depths and different times is established by using the relationship between the temperature at the depth of the point measurement capsule pressure gauge 3 and the temperature at the corresponding depth of DTS changing with time, and the temperature of DTS is corrected according to the DTS correction relationship.

[0040] In a possible implementation, the point measurement capsule pressure gauge 3 is a hollow ring-shaped conical structure and is fixed to the outside of the optical cable 2. Further, one point measurement capsule pressure gauge 3 is fixed to the optical cable 2 every 200 meters.

[0041] In a possible implementation, the point measurement capsule pressure gauge 3 is powered by a battery, and the continuous monitoring time can reach 50 hours.

[0042] In a possible implementation, the optical cable 2 is connected with the logging truck 1 on the ground, and the optical fiber logging ground acquisition system, the logging truck 1, the wellhead tool and other auxiliary equipment are used to complete the optical fiber logging operation. Further, the optical cable 2 is connected with the optical fiber monitoring system and the optical fiber depth system, the optical fiber monitoring system is started, and the optical cable 2 at the positions of the point measuring capsule pressure gauges 3 is sequentially heat marked to determine the positions of the point measuring capsule pressure gauges 3 on the optical fiber depth system.

[0043] The following content takes the target well as the X oilfield flow 2-X shale oil horizontal fracturing well as an example to specifically describe the DTS correction method based on the multi-point capsule pressure gauge of the embodiment of the application, the maximum bottom hole temperature is 130℃, and the following steps are included:

[0044] Before formal logging of the optical cable 2, heat marking is performed. Before the instrument is lowered into the well, the optical fiber monitoring system is started, and the point measuring capsule pressure gauges 3 on the optical cable 2 are sequentially heat marked to determine the positions of the point measuring capsule pressure gauges 3, as shown in Figure 3 The heat marked positions have obvious temperature peaks, and the positions of the point measuring capsule pressure gauges 3 can be clearly determined.

[0045] The instrument is lowered into the well, and the speed, temperature and pressure data and the DTS data are recorded during the lowering process. After the instrument is lowered to the bottom of the well, the DTS data and the point measuring capsule pressure gauge 3 data under different working systems are recorded. The instrument is pulled up, and the speed, temperature and pressure data and the DTS data are recorded during the pulling-up process. The speed data of the embodiment of the application are as shown in Figure 4 The test data of the point measuring capsule pressure gauge of the embodiment of the application are as shown in Figure 5 The optical fiber logging acquisition data of the embodiment of the application are as shown in Figure 6 .

[0046] After the test is completed, the point measuring capsule pressure gauge 3, the DTS and the wellhead speed data are read, and the temperature data of the point measuring capsule pressure gauge 3 are converted into time-depth.

[0047] The relationship between the temperature curves measured by the point measuring capsule pressure gauges 3 and the DTS curves at the similar time is compared, and the relative correction relationship between the DTS temperature and the capsule temperature of different point measuring capsule pressure gauges 3 is established, as shown in Figure 7 .

[0048] The temperature correction relationship of the positions of the point measuring capsule pressure gauges 3 is established by using the time-varying relationship between the temperature at the positions of the point measuring capsule pressure gauges 3 and the corresponding depth temperature of the DTS, as shown in Figure 8 .

[0049] Combined with the above data, the DTS correction relationship at different depths and different times is established, the DTS is temperature corrected, the DTS data before correction is as shown in Figure 9 , and the data after correction is as shown in Figure 10As shown, it can be seen that the corrected data matching is obviously better.

[0050] The application provides a DTS correction device and method based on a multi-point capsule pressure gauge, which adopts a mode of an optical cable and a plurality of point measurement capsule pressure gauges to perform monitoring, and first calibrates the depth of the optical cable corresponding to the point measurement capsule pressure gauge by a thermal marker during collection, and a correction relationship chart between the DTS monitoring temperature and the pressure gauge monitoring temperature of each monitoring point is established by a multi-point scale and a linear interpolation method, the DTS correction amount between the pressure gauges is realized by the linear interpolation method, and finally, the fine correction of the DTS of the whole well section is realized.

[0051] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A DTS correction method based on multi-point capsule pressure gauges, characterized in that, It comprises the following steps: Thermal marking is performed on the point measuring capsule pressure gauges (3) on the optical cable (2) in sequence to determine the positions of the point measuring capsule pressure gauges (3); During the process of lowering the optical cable (2) along the casing (5) into the well, the speed, temperature and pressure data and DTS data are recorded; After the optical cable (2) is lowered to the bottom of the well along the casing (5), data recording of DTS and point measuring capsule pressure gauges (3) under different working systems is started; The optical cable (2) is pulled up along the casing (5), and the speed, temperature and pressure data and DTS data are recorded during the pulling-up process; After the test is completed, the point measuring capsule pressure gauges (3), DTS and wellhead speed data are read, and the temperature data of the point measuring capsule pressure gauges (3) are converted into time-depth; The relationship between the temperature curves measured by the point measuring capsule pressure gauges (3) and the DTS curves at the corresponding time is compared to establish the relative correction relationship between the DTS temperature and the capsule temperature at different point measuring capsule pressure gauges (3); The temperature correction relationship at the positions of the point measuring capsule pressure gauges (3) is established by using the relationship between the temperature at the positions of the point measuring capsule pressure gauges (3) and the temperature at the corresponding depths of DTS over time; The DTS correction relationship at different depths and different times is established by combining the above data, and the temperature of DTS is corrected.

2. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, The step of sequentially performing thermal marking on the point measuring capsule pressure gauges (3) on the optical cable (2) to determine the positions of the point measuring capsule pressure gauges (3) is performed before the optical cable (2) is lowered into the well, the optical fiber monitoring system is turned on, thermal marking is performed on the point measuring capsule pressure gauges (3) on the optical cable (2) in sequence to determine the positions of the point measuring capsule pressure gauges (3) on the optical fiber depth system, and the positions of the point measuring capsule pressure gauges (3) are determined according to the temperature peak of the thermal marking position.

3. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, A counterweight (4) is arranged at the bottom of the optical cable (2) to enable the optical cable (2) to be vertically lowered into the well along the casing (5).

4. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, The point measuring capsule pressure gauges (3) are in a hollow ring-shaped conical structure and are fixed to the outside of the optical cable (2).

5. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, One point measuring capsule pressure gauge (3) is fixed to the optical cable (2) every 200 meters.

6. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, The point measuring capsule pressure gauges (3) are powered by batteries, and the continuous monitoring duration can reach 50 hours.

7. The DTS correction method based on multi-point capsule pressure gauges of claim 1, wherein, A DTS correction device based on multiple point measuring capsule pressure gauges is used for implementation, the DTS correction device based on multiple point measuring capsule pressure gauges comprises an optical cable (2) lowered into a well along a casing (5), multiple point measuring capsule pressure gauges (3) are arranged on the optical cable (2) at heights corresponding to different reservoirs (6), the depths of the point measuring capsule pressure gauges (3) are determined by thermal marking, the relationship between the temperature at the depths of the point measuring capsule pressure gauges (3) and the temperature at the corresponding depths of DTS over time is used to establish the DTS correction relationship at different depths and different times in the well, and the temperature of DTS is corrected according to the DTS correction relationship.

8. The DTS calibration method based on multi-point capsule pressure gauges of claim 7, wherein, The DTS correction device based on the multi-point capsule pressure gauge comprises a fiber monitoring system and a fiber depth system, the optical cable (2) is connected with the fiber monitoring system and the fiber depth system, the fiber monitoring system is started, the optical cable (2) at the positions of the fixed point measuring capsule pressure gauges (3) is sequentially heat marked, and the positions of the fixed point measuring capsule pressure gauges (3) on the fiber depth system are determined.

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