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 tripped into a well along a casing, a plurality of point measurement capsule pressure gauges are arranged on the optical cable corresponding to the heights of different reservoirs, and the depth of each point measurement capsule pressure gauge is determined through thermal marks. And establishing a DTS correction relationship between different depths and different times in the well by using a time-varying relationship between the temperature of the depth where the point measurement capsule pressure gauge is located and the temperature of the depth corresponding to the DTS, and performing temperature correction on the DTS according to the DTS correction relationship. Aiming at an oil-water well with large inclination change, the actual refractive index of an optical fiber is greatly influenced by well inclination, and the optical fiber DTS logging precision is low and the stability is poor, in order to obtain the real DTS temperature response characteristics of a shaft, a plurality of point measurement capsule pressure gauges are additionally arranged on an optical cable, and a multi-point calibration and continuous curve calibration combined method is adopted, so that the acquired data information is enriched; a temperature drift correction reference point is changed from an original single point to a full well section.

Description

Technical Field

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

[0002] With the deepening of exploration and development, various oil fields have generally adopted horizontal well staged fracturing technology to increase the production of single wells, but there has been a lack of effective means to dynamically monitor and evaluate the production capacity of horizontal wells. In recent years, distributed optical fiber logging (DTS / DAS) technology has attracted widespread attention from users due to its advantages of small size, light weight, anti-vibration, anti-interference, low power consumption, high sensitivity, ultra-high temperature and pressure resistance, etc. Its application surface, application scenarios and application scale are constantly expanding, such as shale oil and gas horizontal well dynamic output monitoring, fracturing monitoring, water plugging guidance, etc. The rapid development of distributed optical fiber logging dynamic monitoring technology makes horizontal well staged fracturing monitoring and evaluation possible, and is expected to become a technical tool to guide production logging to the middle and high end. However, at the same time, the optical fiber is affected by the fluctuation of the excitation light source, the unreasonable setting of the refractive index, the state of the optical cable in the drum and extension, the temperature and pressure environment, etc., resulting in temperature drift in DTS logging, affecting the quality of DTS data and limiting the further development of optical fiber logging. During existing fiber optic logging, a storage-type temperature and pressure gauge is simultaneously lowered into the bottom of the optical fiber to achieve full-process monitoring of bottom hole temperature and pressure data. The bottom hole temperature data monitored by it is used as a reference to perform an overall correction of the DTS temperature. This method can achieve certain results in vertical wells and absolutely horizontal wells, but since the actual refractive index of the optical fiber is greatly affected by the well inclination, the application effect is generally poor in oil and water wells with large inclination changes. Therefore, it is urgent to develop a new temperature drift correction method to solve the technical bottleneck problems of low accuracy and poor stability of fiber optic DTS logging. Summary of the invention

[0003] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a DTS correction device and method based on a multi-point capsule pressure gauge. A plurality of point-measuring capsule pressure gauges are arranged on an optical cable for monitoring, and a correction relationship chart between the DTS monitoring temperature of each monitoring point and the pressure gauge monitoring temperature is established by combining a multi-point scale with a linear interpolation method. The DTS correction amount between the pressure gauges is realized by a linear interpolation method, and finally a fine correction of the DTS of the entire well section is achieved.

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

[0005] A DTS correction device based on a multi-point capsule pressure gauge 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 the heights of different reservoirs, the depth of each point-measuring capsule pressure gauge is determined by thermal marking, and a DTS correction relationship at different depths and times in the well is established by using the relationship between the temperature at the depth of the point-measuring capsule pressure gauge and the temperature at the corresponding depth of the DTS, and temperature correction is performed on the DTS according to the DTS correction relationship.

[0006] Preferably, the point-measuring capsule pressure gauge is a hollow annular conical structure, which is fixed on the outside of the optical cable.

[0007] Preferably, the point-measuring capsule pressure gauge is fixed on the optical cable every 200 meters.

[0008] Preferably, the point-measuring capsule pressure gauge is powered by a battery, and the continuous monitoring time can reach 50 hours.

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

[0010] Preferably, the optical cable is connected to the optical fiber monitoring system and the optical fiber depth system. The optical fiber monitoring system is turned on, and the optical cables of the fixed point capsule pressure gauge positions are thermally marked in turn to determine the positions of the capsule pressure gauges at each point on the optical fiber depth system.

[0011] A DTS calibration method based on a multi-point capsule pressure gauge comprises the following steps:

[0012] Thermally mark the point-measurement capsule pressure gauges on the optical cable in turn to determine the position of each point-measurement capsule pressure gauge;

[0013] When the optical cable is lowered into the well along the casing, the speed, temperature and pressure data, and DTS data are recorded;

[0014] When the optical cable is lowered to the bottom of the well along the casing, the DTS and point-measurement capsule pressure gauge data recording of different working systems begins;

[0015] Lift the optical cable up along the casing, and record the speed, temperature and pressure data, and DTS data during the lifting process;

[0016] After the test, read the point-measurement capsule pressure gauge, DTS, and wellhead velocity data, and perform time-depth conversion on the point-measurement capsule pressure gauge test temperature data;

[0017] Compare the relationship between the temperature curve measured by the capsule pressure gauge at the point measurement and the DTS curve at the corresponding moment, and establish the relative correction relationship between the DTS temperature and the capsule temperature between the capsule pressure gauges at different points;

[0018] The temperature correction relationship of the location of the capsule pressure gauge at each point is established by using the relationship between the temperature at each point and the temperature at the corresponding depth of DTS over time;

[0019] Based on the above data, the DTS correction relationship at different depths and times is established, and the DTS is temperature corrected.

[0020] As a preferred scheme, the step of thermally marking the point-measuring capsule pressure gauges on the optical cable in sequence to determine the position of each point-measuring capsule pressure gauge is performed before the optical cable is lowered into the well. The optical fiber monitoring system is turned on, and the point-measuring capsule pressure gauges on the optical cable are thermally marked in sequence to determine the position of each point-measuring capsule pressure gauge on the optical fiber depth system. The position of each point-measuring capsule pressure gauge is determined based on the temperature peak value at the thermally marked position.

[0021] As a preferred solution, the point-measuring capsule pressure gauge is a hollow annular conical structure, which is fixed on the outside of the optical cable every 200 meters. The point-measuring capsule pressure gauge is battery-powered, and the continuous monitoring time can reach 50 hours.

[0022] As a preferred solution, 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 invention has at least the following beneficial effects:

[0024] For oil and water wells with large inclination changes, the actual refractive index of the optical fiber is greatly affected by the well inclination, and 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, the present invention arranges multiple point-measurement capsule pressure gauges on the optical cable, and uses the measured data to establish a full-time domain and full-depth domain optical fiber DLC temperature correction method to achieve DTS multi-point accurate calibration. At present, the refractive index of the optical fiber is greatly affected by the bending degree of the optical cable, and there is no clear influence relationship between the bending degree of the optical cable and the existing well inclination. The optical fiber refractive index parameter in the existing acquisition software can only be set to a fixed value. The unreasonable refractive index setting restricts the DTS data acquisition accuracy; in addition, the optical cable is affected by the wellbore ambient temperature and pressure, and will undergo certain changes in the fiber layer, resulting in different deviations in the DTS monitoring temperature value under different temperature and pressure environments. The present invention enriches the acquisition data information by adding multiple point-measurement capsule pressure gauges on the optical cable, and combines multi-point calibration with continuous curve calibration method, so as to realize the change of the temperature drift correction reference point from the original single point to the whole well section. The present invention 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 large-scale application of optical fiber logging in various oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 Flow chart of a DTS calibration method based on a multi-point capsule pressure gauge in an embodiment of the present invention.

[0027] Figure 2 A schematic structural diagram of a DTS calibration device based on a multi-point capsule pressure gauge according to an embodiment of the present invention.

[0028] Figure 3 Schematic diagram of heat marking of optical cables according to an embodiment of the present invention.

[0029] Figure 4 A statistical diagram of speed measurement data according to an embodiment of the present invention.

[0030] Figure 5 A statistical graph of test data of a point-measurement capsule pressure gauge according to an embodiment of the present invention.

[0031] Figure 6 Statistical diagram of optical fiber logging acquisition data according to an embodiment of the present invention.

[0032] Figure 7 A comparison curve of the temperature after deep conversion and the adjacent DTS curve of the point-measured capsule pressure meter according to an embodiment of the present invention.

[0033] Figure 8 A comparison graph of the temperature of a capsule pressure gauge at a certain point measured over time and the DTS temperature in an embodiment of the present invention.

[0034] Fig. 9 Waterfall diagram of well Stream 2-X before DTS correction in an embodiment of the present invention.

[0035] Fig.10 Waterfall diagram of DTS correction in well Stream 2-X according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, ordinary technicians in this field can also obtain other embodiments without making creative work.

[0037] In order to obtain the true DTS temperature response characteristics of the wellbore, the present invention proposes a DTS correction device and method based on a multi-point capsule pressure gauge. By arranging multiple point-measurement capsule pressure gauges on the optical cable, the data is used to establish a full-time domain and full-depth domain optical fiber DLC temperature correction method to achieve DTS multi-point precise calibration. At present, the refractive index of the optical fiber is greatly affected by the bending degree of the optical cable, and there is no clear influence relationship between the bending degree of the optical cable and the existing well inclination. The refractive index parameters of the optical fiber in the existing acquisition software can only be set to a fixed value. The unreasonable refractive index setting restricts the accuracy of DTS data acquisition; in addition, the optical cable is affected by the wellbore ambient temperature and pressure, and will undergo certain changes in the fiber layer, resulting in different offsets in the DTS monitoring temperature value under different temperature and pressure environments. The present invention can effectively solve the above technical problems.

[0038] like Figure 1 As shown, the embodiment of the present invention is based on the DTS correction method of the multi-point capsule pressure gauge, and designs an optical cable with a point-measurement capsule pressure gauge; uses the thermal marking method to determine the position of each capsule; measures and records the capsule pressure gauge, DTS, and speed measurement related data during the lowering, bottoming, and lifting processes; performs time-depth conversion on the capsule pressure gauge temperature data; finally, establishes a DTS point measurement curve correction relationship; establishes a DTS continuous time domain curve correction relationship, and completes the DTS continuous curve correction.

[0039] See also Figure 2 The DTS correction device based on the multi-point capsule pressure gauge in the embodiment of the present invention comprises an optical cable 2 lowered into the well along the casing 5, a plurality of point-measurement capsule pressure gauges 3 are arranged on the optical cable 2 corresponding to the heights of different reservoirs 6, the optical cable 2 is vertically lowered into the well along the casing 5, and a counterweight 4 is arranged at the bottom of the optical cable 2. The depth of each point-measurement capsule pressure gauge 3 is determined by thermal marking, and 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, which changes with time, is used to establish the DTS correction relationship at different depths and times in the well, and the DTS is temperature-corrected according to the DTS correction relationship.

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

[0041] In a possible implementation, the point-measuring 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 to the logging vehicle 1 on the ground, and the optical fiber logging operation is completed with the help of the optical fiber logging ground acquisition system, the logging vehicle 1, the wellhead tool and other auxiliary equipment. Further, the optical cable 2 is connected to the optical fiber monitoring system and the optical fiber depth system, the optical fiber monitoring system is turned on, and the optical cable 2 at the fixed point capsule pressure gauge 3 position is thermally marked in turn to determine the position of each point capsule pressure gauge 3 on the optical fiber depth system.

[0043] The following content takes the target well as the horizontal fracturing well of shale oil in stream 2-X of the X oil field as an example to describe in detail the DTS correction method based on the multi-point capsule pressure gauge in the embodiment of the present invention. The maximum bottom temperature of the well is 130° C., and the following steps are included:

[0044] Before the optical cable 2 is officially logged, thermal marking is performed. Before the instrument is lowered into the well, the optical fiber monitoring system is turned on, and the point-measurement capsule pressure gauges 3 on the optical cable 2 are thermally marked in turn to determine the position of each point-measurement capsule pressure gauge 3, such as Figure 3 As shown, there is an obvious temperature peak at the heat mark position, which can clearly determine the position of the point-measurement capsule pressure gauge 3;

[0045] The instrument is lowered into the well, and the speed, temperature and pressure data, and DTS data are recorded during the lowering process. After the instrument reaches the bottom of the well, the DTS and point-measurement capsule pressure gauges of different working systems are started to record data. The instrument is raised, and the speed, temperature and pressure data, and DTS data are recorded during the raising process. The speed measurement data of the embodiment of the present invention is as follows Figure 4 As shown, the test data of the point-measurement capsule pressure gauge of the embodiment of the present invention is as follows Figure 5 As shown, the optical fiber logging data collected by the embodiment of the present invention is as follows Figure 6 shown.

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

[0047] Compare the relationship between the temperature curve measured by the capsule pressure gauge 3 at different points and the DTS curve at similar times, and establish the relative correction relationship between the DTS temperature and the capsule temperature between the capsule pressure gauges 3 at different points, such as Figure 7 shown.

[0048] By using the relationship between the temperature at each point-measured capsule pressure gauge 3 and the temperature at the corresponding depth of DTS over time, a temperature correction relationship at each point-measured capsule pressure gauge 3 is established, such as Figure 8 shown.

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

[0050] The present invention proposes a DTS correction device and method based on a multi-point capsule pressure gauge, which adopts an optical cable + multiple point-measuring capsule pressure gauges mode for monitoring. During data collection, the optical cable depth corresponding to the point-measuring capsule pressure gauge is first calibrated by thermal marking, and a correction relationship chart between the DTS monitoring temperature of each monitoring point and the pressure gauge monitoring temperature is established by a multi-point scale + linear interpolation method. The DTS correction amount between the pressure gauges is realized by a linear interpolation method, and finally the fine correction of DTS in the entire well section is achieved.

[0051] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A DTS calibration device based on a multi-point capsule pressure gauge, characterized in that: The invention comprises an optical cable (2) lowered into a well along a casing (5); a plurality of point-measurement capsule pressure gauges (3) are arranged on the optical cable (2) at heights corresponding to different reservoirs (6); the depth of each point-measurement capsule pressure gauge (3) is determined by thermal marking; a DTS correction relationship at different depths and times in the well 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 depth corresponding to the DTS, which changes with time; and temperature correction of the DTS is performed according to the DTS correction relationship.

2. The DTS calibration device based on a multi-point capsule pressure gauge according to claim 1, characterized in that: The point-measuring capsule pressure gauge (3) is a hollow annular conical structure and is fixed on the outside of the optical cable (2).

3. According to claim 1, the DTS calibration device based on the multi-point capsule pressure gauge is characterized in that: The point-measuring capsule pressure gauge (3) is fixed on the optical cable (2) at intervals of 200 meters.

4. The DTS calibration device based on a multi-point capsule pressure gauge according to claim 1, characterized in that: The point-measuring capsule pressure gauge (3) is powered by a battery, and the continuous monitoring time can reach 50 hours.

5. The DTS calibration device based on a multi-point capsule pressure gauge according to claim 1, characterized in that: The optical cable (2) is vertically lowered into the well along the casing (5), and a counterweight (4) is arranged at the bottom of the optical cable (2).

6. The DTS calibration device based on a multi-point capsule pressure gauge according to claim 1, characterized in that: The optical cable (2) is connected to the optical fiber monitoring system and the optical fiber depth system. The optical fiber monitoring system is turned on, and the optical cables (2) of the fixed point capsule pressure gauges (3) are thermally marked in turn to determine the positions of the capsule pressure gauges (3) at each point on the optical fiber depth system.

7. A DTS calibration method based on a multi-point capsule pressure gauge, characterized in that: The following steps are involved: Thermally marking the point-measuring capsule pressure gauges (3) on the optical cable (2) in sequence to determine the position of each point-measuring capsule pressure gauge (3); When the optical cable (2) is lowered into the well along the casing (5), the velocity, temperature and pressure data, and DTS data are recorded; When the optical cable (2) is lowered to the bottom of the well along the casing (5), data recording of different working systems DTS and point-measurement capsule pressure gauge (3) begins; The optical cable (2) is lifted up along the casing (5), and during the lifting process, the speed, temperature and pressure data, and DTS data are recorded; After the test is completed, the point-measurement capsule pressure gauge (3), DTS, and wellhead velocity measurement data are read, and the test temperature data of the point-measurement capsule pressure gauge (3) is converted into time and depth; Compare the relationship between the temperature curve measured by the point-measurement capsule pressure gauge (3) and the DTS curve at the corresponding moment, and establish a relative correction relationship between the DTS temperature and the capsule temperature between the capsule pressure gauges (3) at different points; By using the relationship between the temperature at each point measuring capsule pressure gauge (3) and the temperature at the corresponding depth of DTS over time, a temperature correction relationship at each point measuring capsule pressure gauge (3) is established; Based on the above data, the DTS correction relationship at different depths and times is established, and the DTS is temperature corrected.

8. The DTS calibration method based on a multi-point capsule pressure gauge according to claim 7, characterized in that: The step of sequentially thermally marking the point-measuring capsule pressure gauges (3) on the optical cable (2) to determine the position of each point-measuring capsule pressure gauge (3) is performed before the optical cable (2) is lowered into the well. The optical fiber monitoring system is turned on, and the point-measuring capsule pressure gauges (3) on the optical cable (2) are sequentially thermally marked to determine the position of each point-measuring capsule pressure gauge (3) on the optical fiber depth system. The position of each point-measuring capsule pressure gauge (3) is determined based on the temperature peak value at the thermally marked position.

9. The DTS calibration method based on a multi-point capsule pressure gauge according to claim 7, characterized in that: The point-measuring capsule pressure gauge (3) is a hollow annular conical structure, fixed on the outside of the optical cable (2) every 200 meters, and the point-measuring capsule pressure gauge (3) is powered by a battery, and the continuous monitoring time can reach 50 hours.

10. The DTS calibration method based on a multi-point capsule pressure gauge according to claim 7, characterized in that: A counterweight (4) is arranged at the bottom of the optical cable (2) so that the optical cable (2) can be vertically lowered into the well along the casing (5).

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