Method for monitoring overflow and leakage positions in real time based on distributed optical fiber
Technical Field
The invention belongs to the technical field of petroleum and natural gas production safety monitoring, and particularly relates to a method for monitoring overflow and leakage positions in real time based on a distributed optical fiber.
Background
Overflow and leakage are common in petroleum and gas drilling operation, once stratum fluid is out of control, overflow can occur, normal drilling operation can not be performed in serious cases, and even ecological environment and underground resources can be seriously damaged; the occurrence of the leakage wastes a large amount of drilling fluid, and the drilling construction has to be interrupted when the leakage is serious, so that the drilling construction period is prolonged, and a large amount of manpower, material resources and financial resources are wasted.
At present, two methods of ground monitoring and underground monitoring are mainly adopted at home and abroad to monitor overflow or leakage in the drilling process. The ground monitoring method is economical and practical, but both the drilling fluid pool liquid level monitoring method and the inlet and outlet flow monitoring method have the problems of delay of finding time of overflow or leakage, poor timeliness and accuracy and the like; although the underground monitoring method is timely, the problem of low monitoring precision caused by distortion of underground data in the transmission process generally exists at present; the method usually needs to stop drilling and then carry out special logging measurement when the position of overflow or loss is required to be determined, and the drilling tripping process and logging operation caused by the method have little influence on the construction progress and the construction cost of the whole drilling process.
In order to solve the problems, the invention provides a method for monitoring overflow and leakage positions in real time based on a distributed optical fiber.
Disclosure of Invention
The invention mainly aims to provide a method for monitoring overflow and leakage positions in real time based on a distributed optical fiber, which can effectively solve the problems of low monitoring precision, poor monitoring timeliness and accuracy and the like in the background technology and can find overflow or leakage in time in the drilling process.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for monitoring overflow and leakage positions in real time based on distributed optical fibers utilizes a distributed optical fiber temperature measurement system to monitor the temperature of drilling fluid returning upwards in an annulus in the drilling process in real time, and overflow lost circulation is found; the overflow well leakage monitoring and alarming system is used for comprehensively analyzing the temperature distribution data of the drilling fluid in the annulus in the actual drilling process of the distributed optical fiber temperature measuring system, timely judging whether overflow or well leakage occurs, giving out the specific well depth of the overflow or well leakage and giving out an alarm, and achieving the technical effect of monitoring the overflow and the well leakage in real time in the drilling process.
Further, distributed optical fiber temperature measurement system, including high power pulse semiconductor laser (1), fixed connection is at laser instrument drive power supply (2) of high power pulse semiconductor laser (1) end, and capillary (3) are fixed in the drilling rod outer wall, installs distributed sensing optical fiber (4) in capillary (3), and two-way fiber coupler (5), wavelength division multiplexer (6) and avalanche photodiode (7) are fixed in the well hole position, and signal processing device (8) erect in ground.
Further, the overflow well leakage monitoring and alarming system comprises a main control computer (9) and an alarming device (10).
The invention provides a method for monitoring overflow and leakage positions in real time based on a distributed optical fiber, which is characterized in that a high-power pulse laser (1), a distributed sensing optical fiber (4), a bidirectional optical fiber coupler (5), a wavelength division multiplexer (6) and an avalanche photodiode (7) are used for monitoring drilling fluid in an annulus in real time in the drilling process, and a signal processing device (8) is used for converting collected photoelectric signals into temperature data of the drilling fluid in the annulus in real time and transmitting the temperature data to a main control computer (9); calculating the temperature of the drilling fluid in the annulus in the drilling process according to the established temperature distribution model of the drilling fluid in the annulus in the drilling process; through the real-time measurement collection of annular internal drilling fluid temperature and the calculation of establishing the model to well drilling in-process, carry out the comprehensive analysis contrast, in time judge whether overflow or lost circulation has taken place to find out the concrete position that overflow or lost circulation took place and send out the police dispatch newspaper, reach and carry out real-time supervision's purpose to overflow and lost circulation in the well drilling process.
The processing flow of the method for monitoring the positions of overflow and leakage in real time based on the distributed optical fiber is as follows:
before drilling begins, the system is initialized, the main control computer sends out an excitation instruction to the distributed optical fiber temperature measurement system, and the distributed optical fiber temperature measurement system carries out self-inspection.
After a system is electrified and initialized, a high-power pulse semiconductor laser (1) emits pulse light with constant frequency, the pulse light synchronously emits pulse driving signal processing devices (8), the pulse light enters a distributed sensing optical fiber (4) fixed beside a drill rod through a bidirectional optical fiber coupler (5) and a wavelength division multiplexer (6), the pulse light generates Raman scattering on the distributed sensing optical fiber (4), back scattering light returns to the wavelength division multiplexer (6), the wavelength division multiplexer (6) filters scattering light with other wavelengths, a stokes optical signal and an Anti-stokes optical signal are sent into an avalanche photodiode (7) to be converted into a voltage signal, and then the voltage signal is converted into temperature data of drilling fluid in an annulus through the signal processing devices (8) and is uploaded to a main control computer (9).
If the signal processing device (8) fails to upload data for N times continuously, the situation that the current devices such as the distributed sensing optical fiber (4), the bidirectional optical fiber coupler (5), the wavelength division multiplexer (6), the avalanche photodiode (7) and the like are possibly in fault or the connection between the distributed optical fiber temperature measurement system and the main control computer (9) is possibly in fault is indicated, and at the moment, the alarm device is triggered to alarm; wherein N is an integer, and the value is not less than 5, preferably 5 or 6 or 7.
Calculating the temperature T of the drilling fluid in the annulus under the normal drilling working condition according to the temperature distribution model of the drilling fluid in the annulus in the drilling processMeterThe temperature T of the drilling fluid in the annulus in the drilling process is measured by a distributed optical fiber temperature measurement systemMeasuring;ΔT=TMeasuring-TMeterΔ T represents the difference between the measured temperature and the calculated temperature; comparing the measured temperature with the temperature calculated at the same time, and if the delta T is continuously greater than a preset threshold value X for A times1When the overflow occurs at the bottom of the well or the equipment fails in the drilling process, the ground alarm equipment gives an alarm; if the well depth position delta T suddenly increases, the continuous time B is greater than a preset threshold value X2And when the overflow occurs at the well depth or the equipment is in failure in the drilling process, the ground alarm equipment gives an alarm. Wherein A, B are integers, and the values are not less than 10.
When the difference value delta T between the actually measured temperature and the calculated temperature at the same moment is less than the preset threshold value Y for C times1When the well leakage or equipment failure occurs at the bottom of the well in the drilling process, the ground alarm equipment gives an alarm; if the well depth position delta T suddenly drops, the number of continuous D times is less than the preset threshold value Y2Indicating that a lost circulation occurred at the well depth during drilling orWhen the equipment fails, the ground alarm equipment gives an alarm. Wherein C, D are integers, and the values are not less than 10.
Compared with the prior art, the invention has the following advantages.
The invention establishes a perfect and reliable accident model in the drilling process, takes the two conditions of the overflow and the lost circulation occurring at the well bottom or a specific well depth into consideration in the real-time monitoring of the overflow and the lost circulation, carries out perfect identification and storage on the temperature distribution data in the drilling process, and ensures the real-time monitoring of the overflow and the lost circulation alarming in the drilling process to be timely and reliable.
The distributed sensing optical fiber adopted by the invention is uncharged, corrosion-resistant and high-pressure-resistant, and can safely operate for a long time in a harmful environment in the underground, and the distributed sensing optical fiber is arranged in the capillary steel pipe and fixed beside the drill rod without moving back and forth in a detection area, so that the temperature balance state in the well can be ensured not to be influenced, and the temperature distribution data of the drilling fluid in the annulus at any depth in the well can be obtained more timely and accurately.
The main control computer of the invention adopts an intelligent monitoring alarm process, has reasonable design of an accident judgment and alarm control process, can stably carry out real-time automatic monitoring in the drilling process under the unattended condition, and can carry out timely and accurate alarm when the overflow well leakage occurs.
Drawings
FIG. 1 is a diagram of a hardware device of a real-time monitoring system corresponding to the method of the present invention;
FIG. 2 is a schematic flow chart of the real-time monitoring and alarming of overflow and lost circulation in the drilling process of the present invention.
Wherein: 1. a high power pulsed semiconductor laser; 2. a laser drive power supply; 3. a capillary tube; 4. a distributed sensing optical fiber; 5. a bidirectional fiber coupler; 6. a wavelength division multiplexer; 7. an avalanche photodiode; 8. a signal processing device; 9. a main control computer; 10. and (5) an alarm device.
Detailed Description
In order to make the achievement of the purpose, technical means, creation features and advantages of the invention simple and clear, the following detailed description of the embodiments of the invention is provided with the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and that all other embodiments obtained by those of ordinary skill in the art without resorting to the details of the invention fall within the scope of the invention.
Fig. 1 is a diagram of a hardware device of a real-time monitoring system corresponding to the method.
The field device comprises a high-power pulse semiconductor laser (1) arranged at a wellhead, a laser driving power supply (2) fixedly connected to the tail end of the high-power pulse semiconductor laser (1), a capillary tube (3) fixed on the outer wall of a drill rod, and a distributed sensing optical fiber (4), a bidirectional optical fiber coupler (5) fixed at the position of a borehole, a wavelength division multiplexer (6) and an avalanche photodiode (7) which are arranged in the capillary tube (3).
The signal processing device (8) located at a remote place is connected with a main control computer (9) through a data line. After the data measured by the distributed sensing optical fiber are transmitted to the main control computer (9), the main control computer (9) carries out corresponding data processing and analysis comparison, timely judges whether overflow or well leakage occurs or not, and finds out the specific position where the overflow or well leakage occurs and gives an alarm if an accident occurs.
The alarm device (10) is connected with the main control computer (9) and receives an alarm instruction sent by the main control computer (9) in real time to alarm.
As shown in fig. 2, the method for monitoring overflow and leakage positions in real time based on distributed optical fiber according to the embodiment of the present invention includes the following steps: the system is initialized, an initial state is obtained, the main control computer automatically establishes contact with the field hardware equipment, whether the hardware equipment is normally connected or not is checked, and if the connection with any equipment fails, the system sends an equipment alarm instruction.
And if the equipment is successfully connected, the main control computer sends an excitation instruction to the distributed optical fiber temperature measurement system to excite the distributed optical fiber temperature measurement system to start working and to start receiving annular drilling fluid temperature distribution data from the field distributed optical fiber temperature measurement system.
When the master control computer analyzes and processes the signalsAfter the uploaded data packet is put, the actual temperature T of the drilling fluid in the annulus in the drilling process is obtainedMeasuringAnd whether the current drilling process has overflow or lost circulation is judged by analysis, and if the current drilling process has overflow or lost circulation, the main control computer sends an alarm instruction to the alarm equipment in time to give an alarm. The method comprises the following specific steps:
if the data uploading of the signal processing device fails for N times, the device is indicated to be possibly failed by the current distributed sensing optical fiber, the wavelength division multiplexer, the avalanche photodiode and other devices or the connection between the distributed optical fiber temperature measurement system and the main control computer, and at the moment, the alarm device is excited to alarm. Wherein N is an integer, and the value is not less than 5, preferably 5 or 6 or 7.
According to the method, a model is established through parameters such as the density of the drilling fluid, the specific heat coefficient, the heat conductivity coefficient and the axial flow velocity of the drilling fluid in the annulus, so that the temperature data of the drilling fluid in the annulus is obtained; in the field practical application, the actual calculated temperature is set as TMeterThe heat transfer model of the drilling fluid in the annulus is as follows:
in the formula:
rho-drilling fluid density, kg/m3;
c-specific heat coefficient, J/(kg. DEG C.);
s-heat source term, W/m3;
λ -thermal conductivity, W/(m.deg.C);
v-axial flow velocity of drilling fluid in the annulus, m/s;
Tmeter-annulus drilling fluid calculated temperature, deg.C.
Calculating the temperature T of the drilling fluid in the annulus according to the temperature distribution model of the drilling fluid in the annulus established by the inventionMeterAnd measuring the temperature T of the drilling fluid in the annulus in real timeMeasuringBy comparison, if TMeasuringAnd TMeterIs greater than a preset threshold value X for a consecutive number A of times1The alarm device on the ground sends out an alarm signal to indicate that the well bottom overflows or the equipment fails in the drilling processAn alarm is given; if the well depth position delta T suddenly increases, the continuous time B is greater than a preset threshold value X2And when the overflow occurs at the well depth or the equipment is in failure in the drilling process, the ground alarm equipment gives an alarm. Wherein A, B are integers, and the values are not less than 10.
When the temperature T of the drilling fluid in the annulus is measuredMeasuringWith calculation of the temperature T at the same timeMeterIs less than a preset threshold value Y for C consecutive times1When the well leakage or equipment failure occurs at the bottom of the well in the drilling process, the ground alarm equipment gives an alarm; if the well depth position delta T suddenly drops, the number of continuous D times is less than the preset threshold value Y2And when the well leakage or equipment failure occurs at the well depth in the drilling process, the ground alarm equipment gives an alarm. Wherein C, D are integers, and the values are not less than 10.
The overflow well leakage monitoring and alarming system can draw dynamic distribution images of temperature in the annulus calculated and actually measured by software in the drilling process in real time, and accurately judge the positions of overflow and well leakage in the drilling process in real time, so that monitoring personnel can monitor the conditions in the well in the drilling process more intuitively and conveniently. The main control computer can automatically read, store and analyze temperature data without manual intervention, and can timely and accurately give an alarm when overflow and lost circulation occur.
While the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that the present invention is not limited to the embodiments, but various changes and modifications may be made without departing from the spirit and scope of the present invention.