CN117846579A - High-frequency pressure fluctuation monitoring device and method based on well shut-in water hammer effect - Google Patents

Abstract

The invention provides a high-frequency pressure fluctuation monitoring device and a method based on a shut-in water hammer effect, wherein the device comprises a pressure fluctuation acquisition module and a data acquisition and processing module, the pressure fluctuation acquisition module is arranged on the inner side of a wellhead casing wall and comprises a high-frequency pressure sensor and a pressure wave receiving window which is integrated with the high-frequency pressure sensor and is used for acquiring a pressure fluctuation signal of wellhead fluid in real time; the data acquisition and processing module is arranged on the outer side of the casing wall of the wellhead and is in communication connection with the high-frequency pressure sensor to convert, analyze, store and display pressure fluctuation signals; the data acquisition and processing module comprises a metal shell, a data acquisition module, a data storage module, a singlechip and a built-in power supply. By adopting the device, the change rule of the wellhead pressure influenced by the water hammer effect at the initial closing stage can be clarified, the accuracy is high, the operation is simple, a large amount of cable resources are not needed to be relied on, and a higher-accuracy calculation result can be obtained when the influence of the impact effect is eliminated and the bottom hole pressure is calculated based on the wellhead pressure.

Description

High-frequency pressure fluctuation monitoring device and method based on well shut-in water hammer effect

Technical Field

The invention relates to the technical field of petroleum well shut-in fluctuation pressure monitoring, in particular to a high-frequency pressure fluctuation monitoring device and method based on a shut-in water hammer effect, which are applied to wellhead pressure monitoring and analysis caused by the water hammer effect in the early stage of petroleum deep well shut-in.

Background

In the closing process of a deep well, the wellhead pressure can quickly recover to the highest point at the initial closing stage and then continuously drops, so that the abnormal phenomenon of pressure recovery is shown. The larger the gas invasion amount is, the larger the amplitude of wellhead pressure change after well closing is, the larger the influence of water hammer effect pressure on the dynamic change of wellhead pressure in the early stage of well closing is, the smaller the influence on the later pressure is, in an actual engineering scene, the instantaneous water hammer effect of part of high-temperature high-pressure gas well wellhead in the early stage of well closing leads the wellhead pressure recovery speed to be obviously greater than the bottom hole pressure recovery speed, so that the actual satisfactory result is obviously difficult to obtain from the calculation of wellhead pressure parameters to the bottom hole pressure condition in the early stage of well closing.

Some researchers currently consider that wellhead pressure drop is mainly caused by wellhead temperature drop after well shut-in. However, according to the wellhead pressure and temperature change curves during the well test of the domestic part of well conditions, the pressure continuously and monotonically decreases after well shut-in, but the temperature does not monotonically decrease, which indicates that the abnormal decrease of the wellhead pressure after well shut-in is not only influenced by the wellhead temperature.

Therefore, it is highly desirable to monitor the fluctuating pressure generated by the water hammer effect in the early stage of well shut-in, understand the variation law of the fluctuating pressure of the water hammer effect, and improve the accuracy of calculating the bottom hole pressure by using the wellhead pressure.

Some scholars in the prior art propose to set up pressure testing equipment at the well head to gather the pressure condition of well head, but its mainly used is sampled to the normal pressure of logging or development in-process pressure, shows the pressure data that pressure sensor detected in real time through the display, can't effectively characterize the change rule of water hammer effect fluctuation pressure and to the influence of bottom of hole true pressure.

The information disclosed in the background section of the invention is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

In order to solve the problems, the invention provides a high-frequency pressure fluctuation monitoring device and a high-frequency pressure fluctuation monitoring method based on a well closing water hammer effect. In one embodiment, the apparatus comprises:

the pressure fluctuation acquisition module is fixedly arranged on the inner side of the wellhead casing wall and is used for acquiring pressure fluctuation signals of wellhead fluid in real time, and comprises a high-frequency pressure sensor and a pressure wave receiving window which is integrated with the high-frequency pressure sensor;

the data acquisition and processing module is arranged on the outer side of the casing wall of the wellhead, is in communication connection with the high-frequency pressure sensor and is used for converting, analyzing, storing and externally displaying pressure fluctuation signals;

the data acquisition and processing module comprises a metal shell, a data acquisition module, a data storage module, a singlechip and a built-in power supply.

Preferably, in one embodiment, the high frequency pressure sensor employs an absolute pressure sensor to prevent interference of the fluid pressure signal acquisition by the atmospheric pressure.

In an alternative embodiment, the pressure wave receiving window is positioned on two sides of the detection protective cover along the bottom of the well, and the pressure of the fluid is monitored by the sensor after passing through the pressure wave receiving window, so that the direct impact effect of the pressure of the fluid on the high-frequency pressure sensor is effectively reduced.

Further, in one embodiment, the pressure fluctuation collecting module further comprises a detection protecting cover, and the opening end of the detection protecting cover is fixedly connected with the inner side of the wellhead casing wall in a sealing way to form a space for wrapping the high-frequency pressure sensor inside.

On the other hand, in one embodiment, the metal casing of the data acquisition and processing module is connected with the wellhead casing wall, a through hole for connecting a high-frequency pressure sensor is reserved near the top end of the wellhead casing wall, and the output end of the high-frequency pressure sensor penetrates through the top end of the metal casing and is connected with the data acquisition module.

In a preferred embodiment, the metal casing is fixedly arranged on the wellhead casing wall by adopting a flange, the top end of the metal casing is positioned on the inner side of the wellhead casing wall and is provided with a fixed connection flange, the metal casing is arranged on the outer side of the wellhead casing wall and is provided with a movable connection flange, the bottom end of the fixed connection flange is fixedly connected with the top end of the movable connection flange through a connection bolt, and the movable connection flange can slide outside the metal casing and can be flexibly adjusted according to the thickness of the wellhead casing wall.

Specifically, in an alternative embodiment, the data acquisition module is controlled by the singlechip to record a fluctuating pressure value according to the period of each microsecond, generate a group of fluctuating waveform data according to the period of each second, and transmit the fluctuating waveform data to the singlechip.

Further, in one embodiment, the data acquisition module is configured to:

converting the measured pressure wave surface into a surface waveform; pressure spectrum conversion is applied on the low frequency side to obtain a surface spectrum so as to extract waveform characteristics of a waveform corresponding to the fluctuating pressure.

As a further improvement of the invention, in one embodiment, the bottom end of the metal casing of the data acquisition and processing module, which is far away from the casing wall of the wellhead, is provided with a status light and a convenient switch.

Specifically, in an optional embodiment, the singlechip is configured to strip two fluctuation curves according to different fluctuation pressures and waveform characteristics, and further identify a time when the effective wave height is greater than a threshold value based on a preset waveform automatic encryption wave height threshold value, generate corresponding prompt information, and control the state lamp to be started.

Preferably, in one embodiment, the bottom end of the metal casing of the data acquisition and processing module far away from the wellhead casing wall is further provided with an external interface, one end of the external interface is connected with the single chip microcomputer, and the other end of the external interface is connected with the external data processing system and is used for transmitting pressure fluctuation data, waveform data and identification result information.

Based on the application aspect of the device in any one or more of the embodiments, the invention further provides a high-frequency pressure fluctuation monitoring method based on the shut-in water hammer effect, which comprises the following steps:

when the time interval to be detected of the shut-in well is determined, starting the high-frequency pressure fluctuation monitoring device of the shut-in well water hammer effect;

the singlechip controls the data acquisition module to acquire a real-time fluctuation pressure value according to each micro period, and converts the actually measured pressure wave surface into a surface waveform according to each second period;

applying a pressure spectrum at a low frequency side so as to obtain a surface spectrum through conversion, and further extracting waveform characteristics of waveforms corresponding to the fluctuation pressure;

converting the acquired waveform characteristic data into a discrete digital sequence by utilizing a singlechip, and storing or uploading the discrete digital sequence to an external data processing system;

the data processing system carries out waveform reconstruction and waveform parameter measurement on the converted waveform corresponding digital sequence, and displays the waveform to a user in real time through an interactive interface, wherein the waveform reconstruction is realized by adopting a waveform interpolation method.

Based on other aspects of the apparatus described in any one or more of the embodiments above, the present invention also provides a storage medium having stored thereon program code that can implement a method as described in the embodiments above.

Compared with the closest prior art, the invention has the following beneficial effects:

the invention provides a high-frequency pressure fluctuation monitoring device based on a shut-in water hammer effect, which comprises: the pressure fluctuation acquisition module is fixedly arranged on the inner side of the wellhead casing wall and comprises a high-frequency pressure sensor and a pressure wave receiving window which is integrated with the high-frequency pressure sensor and is used for acquiring pressure fluctuation signals of wellhead fluid in real time; the monitoring sensitivity to the fluctuation pressure is high, and the monitoring and identification of the tiny fluctuation pressure can be realized; the pressure fluctuation signal which changes with time during the measurement can be obtained efficiently, conveniently and quickly;

the data acquisition and processing module is arranged on the outer side of the casing wall of the wellhead and is in communication connection with the high-frequency pressure sensor to convert, analyze, store and display pressure fluctuation signals; the data acquisition and processing module comprises a metal shell, a data acquisition module, a data storage module, a singlechip and a built-in power supply. The data acquisition module is used for acquiring the fluctuation pressure data and the waveform characteristic data in real time, the software resource of the singlechip is fully utilized, the change rule of the wellhead pressure influenced by the water hammer effect in the early closing stage is clarified, the circuit is simple, the power consumption is low, the reliability is high, the accuracy is high, the operation is simple, a large amount of cable resources are not needed to be relied on, the influence of the impact effect is eliminated, a calculation result with higher accuracy can be obtained when the bottom hole pressure is calculated based on the wellhead pressure, and a theoretical basis is provided for early well testing explanation.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention, without limitation to the invention. In the drawings:

FIG. 1 is a schematic diagram of a connection structure of an existing wellhead pressure tester provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of an example of a conventional downhole shut-in pressure measurement device according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a high-frequency pressure fluctuation monitoring device based on the well shut-in water hammer effect according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a high-frequency pressure fluctuation monitoring device based on the well shut-in water hammer effect in a front cross-section manner;

FIG. 5 is a schematic diagram of an installation mode of a high-frequency pressure fluctuation monitoring device based on a shut-in water hammer effect according to another embodiment of the present invention;

in the accompanying drawings: 1. the device comprises a detection protective cover, 2, a metal shell, 3, a switch, 4, a status lamp, 5, an external interface, 6, a high-frequency pressure sensor, 7, a data acquisition module, 8, a data storage module, 9, a single chip microcomputer, 10, a power supply, 11, a fixed connection flange, 12, a movable connection flange, 13, a connection bolt, 14, a pressure wave receiving window, 15, a protective shell, 16, a fluctuation pressure monitoring device, 17, a data transmission line, 18, a data processing system, 19 and fluctuation pressure.

Detailed Description

The following will explain the embodiments of the present invention in detail with reference to the drawings and examples, so that the practitioner of the present invention can fully understand how to apply the technical means to solve the technical problems, achieve the implementation process of the technical effects, and implement the present invention according to the implementation process. It should be noted that, as long as no conflict is formed, each embodiment of the present invention and each feature of each embodiment may be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items. When an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In the closing process of a deep well, the wellhead pressure can quickly recover to the highest point at the initial closing stage and then continuously drops, so that the abnormal phenomenon of pressure recovery is shown. The larger the gas invasion amount is, the larger the amplitude of wellhead pressure change after well closing is, the larger the influence of water hammer effect pressure on the dynamic change of wellhead pressure in the early stage of well closing is, the smaller the influence on the later pressure is, in an actual engineering scene, the instantaneous water hammer effect of part of high-temperature high-pressure gas well wellhead in the early stage of well closing leads the wellhead pressure recovery speed to be obviously greater than the bottom hole pressure recovery speed, so that the actual satisfactory result is obviously difficult to obtain from the calculation of wellhead pressure parameters to the bottom hole pressure condition in the early stage of well closing.

Some researchers currently consider that wellhead pressure drop is mainly caused by wellhead temperature drop after well shut-in. However, according to the wellhead pressure and temperature change curves during the well test of the domestic part of well conditions, the pressure continuously and monotonically decreases after well shut-in, but the temperature does not monotonically decrease, which indicates that the abnormal decrease of the wellhead pressure after well shut-in is not only influenced by the wellhead temperature.

Therefore, it is highly desirable to monitor the fluctuating pressure generated by the water hammer effect in the early stage of well shut-in, understand the variation law of the fluctuating pressure of the water hammer effect, and improve the accuracy of calculating the bottom hole pressure by using the wellhead pressure.

Some scholars in the prior art propose to set pressure test equipment at a wellhead to collect pressure conditions of the wellhead, but the pressure test equipment is mainly used for sampling normal pressure of pressure in a logging or developing process, for example, CN204186378U provides a wellhead pressure test instrument, a structural diagram is shown in fig. 1, pressure data detected by a pressure sensor is displayed in real time through a display, the pressure data detected by the pressure sensor can be printed in real time through a printer, and the pressure data detected by the pressure sensor can be stored through a memory; the change rule of the surge pressure of the water hammer effect and the influence on the bottom hole real pressure cannot be effectively represented. CN202064936U provides a wireless transmission underground shut-in pressure measuring device, the structure is shown in fig. 2, the underground pressure and temperature are continuously monitored for a long time, and the underground pressure and temperature data are read at any time; the test device is suitable for testing pumping wells, self-injection wells and water injection wells under different well depths, and can realize the time period test setting of test points. However, the monitoring of the fluctuation pressure of the shut-in well cannot be realized, and the length of a required cable wire is increased along with the deeper monitoring depth, so that the cable wire is possibly entangled due to rock fragments and the use is influenced when the economic benefit is not met. CN204186378U provides a well head electric current pressure tester, can measure the beam-pumping unit electric current, can monitor well head pressure, stores historical monitoring data, can also report to the police when storage space is not enough and suggestion. However, the scheme aims at describing the communication circuit structure of the data flow, lacks specific real-time measures and detailed setting guidance, is ambiguous in implementation concept and is difficult to put into use.

In order to solve the problems, the invention provides the high-frequency pressure fluctuation monitoring device and the method based on the well closing water hammer effect, the device is arranged at a wellhead, a cable is not needed to be hung, the well closing fluctuation pressure of the wellhead is monitored in real time, the sensitivity is high, the device is compact, the equipped high-precision pressure sensor can monitor the fluctuation pressure generated by the well closing water hammer effect, the detection protection cover is arranged, the sensor can be prevented from being damaged by impact, the pressure data can be stored while being monitored, and the device can be connected to an external data processing system through an external interface in a communication mode, so that the waveform reconstruction and the data visualization processing are realized. Based on the detailed device structure guidance and implementation measures provided by the invention, the change rule of the wellhead pressure influenced by the water hammer effect in the early closing stage can be clarified, so that the influence of the impact effect is eliminated when the bottom hole pressure is calculated from the wellhead pressure, a higher-precision calculation result can be obtained, and a theoretical basis is provided for early well test interpretation.

The detailed structure, arrangement and operation principle of the monitoring device according to the embodiment of the present invention are described in detail below based on the drawings. Although the logical order of operations are depicted in the context of describing the principles of operation, in some cases the operations depicted or described may be performed in a different order than is shown or described herein.

Example 1

Fig. 3 is a schematic structural diagram of a high-frequency pressure fluctuation monitoring device based on a well shut-in water hammer effect according to an embodiment of the present invention, and referring to fig. 3, it can be known that the device includes:

the pressure fluctuation acquisition module is fixedly arranged on the inner side of the wellhead casing wall and is used for acquiring pressure fluctuation signals of wellhead fluid in real time and comprises a high-frequency pressure sensor 6 and a pressure wave receiving window 14 which is integrated with the high-frequency pressure sensor 6;

the data acquisition and processing module is arranged on the outer side of the casing wall of the wellhead, is in communication connection with the high-frequency pressure sensor and is used for converting, analyzing, storing and externally displaying pressure fluctuation signals;

the data acquisition and processing module comprises a metal shell 2, a data acquisition module 7, a data storage module 8, a singlechip 9 and a built-in power supply 10, as shown in fig. 4.

By adopting the monitoring device in the embodiment, the change rule of the wellhead pressure influenced by the water hammer effect in the early closing stage can be clarified, so that the influence of the impact effect is eliminated when the bottom hole pressure is calculated from the wellhead pressure, a higher-precision calculation result can be obtained, and a theoretical basis is provided for early well test interpretation. Furthermore, the external data processing system connected with the external interface can separate fluctuation frequency information from the monitored fluctuation pressure data, so that corresponding fluctuation frequency can be analyzed while the fluctuation pressure change rule is collected.

In a preferred embodiment, the high-frequency pressure sensor is an absolute pressure sensor, so that interference of the atmospheric pressure on acquisition of a fluid pressure signal is prevented.

Further, in one embodiment, the pressure fluctuation collecting module further comprises a detection protecting cover, and the opening end of the detection protecting cover is fixedly connected with the inner side of the wellhead casing wall to form a space for wrapping the high-frequency pressure sensor inside.

In practical application, in one embodiment, the pressure wave receiving window is arranged, so that the direct impact effect of fluid pressure on the high-frequency pressure sensor is effectively slowed down, and the sensor is prevented from being damaged due to impact of larger pressure. In an alternative embodiment, the pressure wave receiving windows are arranged on two opposite sides of the detection protective cover along the bottom hole direction, and can be expressed as an upper opening and a lower opening which are close to the casing wall of the wellhead, and the sizes of the openings are configured according to the size of a shaft and the attribute parameters of the pressure sensor; when the pressure sensor is applied, the high-frequency pressure sensor is positioned at the bottom inside the protective cover and is in an axis with the pressure wave receiving window, the pressure of fluid can be monitored through the pressure wave receiving window by the sensor, and the pressure can be buffered by detecting the protective cover on the basis of effectively realizing the measurement of fluid pressure fluctuation, so that the sensor is prevented from being damaged by overlarge impact pressure wave.

In a preferred embodiment, the metal shell of the data acquisition and processing module is connected with the wellhead casing wall, a through hole for connecting a high-frequency pressure sensor is reserved near the top end of the wellhead casing wall, and the output end of the high-frequency pressure sensor penetrates through the metal shell and is connected with the data acquisition module.

Specifically, in an alternative embodiment, the metal casing is fixedly arranged on the wellhead casing wall by adopting a flange, the top end of the metal casing is positioned on the inner side of the wellhead casing wall, a fixed connection flange 11 is arranged on the outer side of the wellhead casing wall, a movable connection flange 12 is arranged on the metal casing, the bottom end of the fixed connection flange is fixedly connected with the top end of the movable connection flange through a connection bolt, and the movable connection flange can slide outside the metal casing and can be flexibly adjusted according to the thickness of the wellhead casing wall. When in practical application, the opening edge of the wellhead casing wall is just clamped between the fixed connecting flange and the movable connecting flange.

Further, in the process of monitoring, the data acquisition module is controlled by the singlechip to record a fluctuation pressure value according to the period of each microsecond, generate a group of fluctuation waveform data according to the period of each second, and transmit the fluctuation waveform data to the singlechip.

In an alternative embodiment, the data acquisition module is further configured to:

converting the measured pressure wave surface into a surface waveform; the pressure spectrum is applied on the low frequency side and converted to a surface spectrum to extract the waveform characteristics of the waveform corresponding to the fluctuating pressure.

As a further improvement of the invention, in a preferred embodiment, the bottom end of the metal casing of the data acquisition and processing module, which is far away from the casing wall of the wellhead, is provided with a status light and a convenient switch.

In practical application, in one embodiment, the singlechip is configured to strip two fluctuation curves according to different fluctuation pressures and waveform characteristics, and further identify the moment when the effective wave height is greater than a threshold value based on the preset wave height threshold value of automatic waveform encryption, generate corresponding prompt information, and control the state lamp to be started.

The convenient switch can be used for on-site staff to control the on-off of the monitoring device according to the real-time monitoring state.

Further, in a preferred embodiment, the bottom end of the metal casing of the data acquisition and processing module far away from the wellhead casing wall is further provided with an external interface, one end of the external interface is connected with the singlechip, and the other end of the external interface is connected with an external data processing system and is used for transmitting pressure fluctuation data, waveform data and identification result information; in practical application, the external interface 5 can be arranged outside the wellhead by adopting an optical fiber transmission interface so as to efficiently and high-speed carry out data transmission, prevent data distortion in the transmission process and be connected with a data processing system.

In an alternative embodiment, a protective housing 15 is provided in connection with the bottom end of the metal housing, enclosing the status light, the convenience switch and the external interface.

In practical application, in a preferred embodiment, the detection protection cover 1 and the metal shell 2 are made of titanium alloy materials, and the protection shell 15 is made of stainless steel materials;

in summary, the high-frequency pressure fluctuation monitoring device and method based on the well closing water hammer effect in the embodiment of the invention comprise a detection protection cover 1, a metal shell 2 and a protection shell 15, wherein the pressure fluctuation monitoring device is composed of a high-precision high-frequency pressure sensor 6, a data acquisition module 7, a data storage module 8, a singlechip 9 and the like, and is designed to fully utilize software resources of the singlechip, and replace a hardware circuit as far as possible by adopting a software method, so that the circuit of the instrument is simple, the power consumption is low, the reliability is high, the self-contained working time is long, the real-time data processing capability is realized, the fluctuation encryption observation can be automatically carried out according to a preset wave height threshold value, in addition, the detection protection cover is configured, the high-frequency pressure sensor can be effectively prevented from being damaged by impact of larger pressure, and the set pressure wave receiving window can effectively alleviate the impact effect of the pressure.

The detection protective cover 1 and the metal shell 2 are made of titanium alloy materials, the protective shell 15 is made of stainless steel materials, the external interface 5 is an optical fiber transmission interface and is arranged outside a wellhead so as to efficiently and high-speed carry out data transmission, prevent data distortion in the transmission process and be connected with the data processing system 18.

The high-frequency pressure sensor 6 adopts an absolute pressure sensor, the interference of atmospheric pressure on data acquisition is prevented, the one end of the high-frequency pressure sensor 6 penetrates through the top end of the metal shell 2 and is connected with the data acquisition module 7, the top end of the metal shell 2 is provided with a fixed connection flange 11, the outside of the metal shell 2 is provided with a movable connection flange 12, the bottom end of the fixed connection flange 11 is fixedly connected with the top end of the movable connection flange 12 through a connection bolt 13, the movable connection flange 12 can slide outside the metal shell 2, a device can be flexibly fixed according to the wall thickness of a wellhead sleeve, the bottom end of the metal shell 2 is provided with a switch 3, a status lamp 4 and an external interface 5, one end of the external interface 5 penetrates through the bottom end of the metal shell 2 and is connected with the data storage module 8, the data acquisition module 7 records a fluctuation pressure value every microsecond and records a group of fluctuation waveform data calculation every second, and the inside of the metal shell 2 is provided with a power supply 10 for supplying power to the internal module and the status lamp 4.

In practical application, the external interface 5 is used for exporting data in the data storage module, the data storage module is used for storing various acquired data, including data with time variation and waveform characteristic data, the storage module adopts a storage structure which is more than 16MB, three months of data are continuously stored, the data processing system 18 is used for operating the data after exporting the data, and the data in the storage module is automatically cleared under the control of a singlechip instruction after exporting the data.

The high-frequency pressure fluctuation monitoring device based on the well closing water hammer effect is arranged on the casing wall of a wellhead, as shown in fig. 5, a data acquisition module 7 is utilized for acquiring a fluctuation array, acquired data comprises fluctuation pressure and waveform characteristics, a fluctuation period is in seconds, the fluctuation pressure is in microseconds, two fluctuation curves are peeled off according to the difference of the fluctuation pressure and the waveform characteristics, a wave height threshold value for waveform automatic encryption can be set, and when the calculated effective wave height is larger than the wave height threshold value, a status lamp 4 can flash to prompt that the acquired fluctuation pressure can cause the wellhead pressure to be excessively high.

The waveform measurement is based on converting the actually measured pressure wave surface into a surface waveform, and in order to obtain each element of the surface waveform, the pressure spectrum is converted into the surface spectrum at the low frequency side, so that the waveform characteristics displayed by the fluctuation pressure can be conveniently extracted;

wave mode conversion occurs between transverse and longitudinal waves that wave-propagate in both media, thereby producing surface waves. In the patent, surface waves are transmitted from the bottom of a well to the wellhead along the well wall, and can be monitored by using a related measuring device.

According to the instruction of the singlechip, the distortion frequency is subjected to depth conversion (filtering treatment) to obtain a surface spectrum by using the existing spectrum conversion method (Blackman-Tukey method) and applying a pressure spectrum to the low-frequency side according to the small-amplitude simple fluctuation theory.

Specifically, in an alternative embodiment, the data acquisition module acquires pressure data and waveform characteristics, and further strips the fluctuation pressure curve and the waveform characteristic curve through the singlechip, realizes curve stripping according to different recording periods (microseconds/second) of the abscissa, and respectively draws curves for the two groups of data sets.

And recording a fluctuation pressure numerical curve formed by a fluctuation pressure value every microsecond and a fluctuation waveform curve formed by a group of fluctuation waveform data every second, wherein the waveform curve is controlled by a singlechip, and recording the pressure peak value after filtering processing to represent waveform characteristics.

Recording the pressure value of each point by the fluctuation pressure value curve to draw a curve, and representing a data curve; the wave form curve only records the peak to form a pressure wave, which characterizes the wave form curve.

In the monitoring process, pressure data acquired every microsecond are used as original data; the fluctuation pressure forms a pressure wave, the pressure fluctuation is collected to obtain waveform characteristics, the waveform characteristics represent the fluctuation condition of the fluctuation pressure peak value, the data are specifically related to the principle of the adopted pressure wave meter, the newly collected waveform data have serious noise and unstable characteristics, therefore, the data are subjected to low-pass filtering processing by using a singlechip to apply pressure spectrum to remove high-frequency signal noise, a waveform curve with obvious characteristics is formed, and the waveform curve is stored in a data storage module. Wherein the pressure data is stored as a first data set and the surface waveform data is stored as a second data set.

Further, the data processing system 18 receives the original pressure data and the surface waveform data through the external interface 5, remotely processes the data and draws corresponding curves according to the requirements.

The high-frequency pressure sensor 6 receives the shut-in fluctuation pressure 19, then carries on the data processing to the waveform data collected through the single-chip microcomputer 9, turn into the discrete digital sequence and is captured, stored in the data storage module 8, can upload to the data processing system 18, utilize the data processing system 18 to process and calculate the waveform data after turning into, including waveform reconstruction and waveform parameter measurement, the waveform processing adopts the method of waveform interpolation to realize the waveform reproduction, the invention adopts the processing method of sinusoidal interpolation, its principle is to utilize mathematical processing, calculate out the result in the interval of actual sample point, can also obtain the internal each point data of the sample interval while expanding the collection interval, realize the waveform reproduction that the bending curvature characteristic is more obvious.

The data storage module 8 can store the pressure data monitored by the high-frequency pressure sensor 6 so as to be uploaded to the data processing system 18, the data processing system 18 can display the pressure data monitored by the high-frequency pressure sensor 6 and the converted waveform characteristic curve in real time through a display, so that the traceability of the data is improved, the relation between the two curves is analyzed, and the status lamp 4 can flash when the fluctuation pressure is too high;

well shut-in operations in oil and gas well production can bring about changes in wellhead pressure, mainly resulting from water hammer pressure and well shut-in pressure recovery. The water hammer pressure can cause the instantaneous increase of the wellhead pressure of the shut-in well, and the effect of the recovery of the shut-in well pressure on the increase of the wellhead pressure is continuously increased along with the time. For gas wells, the well shut-in water hammer effect is related to gas compressibility. The impact effect of well shut-in is the abrupt change of flow near the well mouth, and the impact of gas to the well mouth valve due to the inertia effect, the gas compressibility and the impact to the valve make the well mouth pressure rise rapidly. After the well is shut in, the water hammer wave propagates downwards, and the wave reflection is caused when the water hammer wave reaches the bottom of the well. Expansion of the bottom hole fluid back into the formation and tubing may also be caused when the well is shut in too quickly. Such pressure waves gradually decay to disappear during propagation due to gas friction losses, incomplete elasticity with the pipe wall, etc.

When the well is closed in an emergency, the water hammer pressure monitoring and calculating model is as follows under the condition of not considering the expansion of the oil pipe and the temperature change of the well shaft:

Ph＝ρcv0

wherein: ph is the water hammer pressure, MPa; ρ is wellbore fluid density, kg/m3; v0 is the flow rate of the well bore fluid before shut-in, m/s; and c is the pressure propagation speed, m/s.

Compared with the prior art, the high-frequency pressure fluctuation monitoring device based on the well closing water hammer effect has the following beneficial effects:

1. the high-frequency sensor has high sensitivity and can effectively monitor and identify any tiny fluctuation pressure in a well closing stage.

2. After the well is shut in, the fluctuation pressure generated by the water hammer effect causes excessive upward flushing of the wellhead pressure, and the device can monitor the change amplitude of the wellhead pressure and analyze the change rule.

3. The bottom of the metal shell of the device is provided with the status lamp and the external switch, which is convenient for the staff to open/close the device and has a clear view on the activity state of the device.

4. The device is used for controlling a data acquisition module to acquire a fluctuation array through a singlechip, filtering the fluctuation array, converting a measured pressure wave surface into a surface waveform, converting the pressure spectrum into the surface spectrum at a low frequency side for obtaining each element of the surface waveform, measuring the pressure fluctuation caused by the surface wave by using a high-resolution sensor, and carrying out statistical analysis on waveform data according to the relation between the wave surface and the fluctuation pressure by software according to a linear wave theory to obtain characteristic parameters such as wave height, wave period and the like.

5. The high-frequency high-precision pressure data obtained through monitoring are processed, the fluctuation waveform information is separated from the pressure data, so that staff can efficiently, conveniently and quickly obtain the fluctuation waveform elements changing along with time in the measuring period, and software is simple and flexible to use, wide in computing application platform, high in computing speed and accurate in computing the fluctuation waveform elements.

In the high-frequency pressure fluctuation monitoring device based on the well shut-in water hammer effect, each module or unit structure can independently or in combination operate according to actual monitoring requirements and data processing requirements so as to achieve corresponding technical effects.

Example two

The connection relation and the operation logic of each component of the device are described in detail in the embodiment disclosed by the invention, and based on other aspects of the device in any one or more embodiments, the invention also provides a high-frequency pressure fluctuation monitoring method based on the well shut-in water hammer effect, which is applied to the high-frequency pressure fluctuation monitoring device based on the well shut-in water hammer effect in any one or more embodiments. Specific examples are given below for details.

Correspondingly, the invention also provides a high-frequency pressure fluctuation monitoring method based on the well shut-in water hammer effect, which comprises the following steps:

when the time interval to be detected of the shut-in well is determined, starting the high-frequency pressure fluctuation monitoring device of the shut-in well water hammer effect;

the singlechip controls the data acquisition module to acquire a real-time fluctuation pressure value according to each micro period, and converts the actually measured pressure wave surface into a surface waveform according to each second period;

applying a pressure spectrum at a low frequency side so as to obtain a surface spectrum through conversion, and further extracting waveform characteristics of waveforms corresponding to the fluctuation pressure;

converting the acquired waveform characteristic data into a discrete digital sequence by utilizing a singlechip, and storing or uploading the discrete digital sequence to an external data processing system;

and carrying out waveform reconstruction and waveform parameter measurement on the converted waveform corresponding digital sequence by a data processing system, and displaying the waveform corresponding digital sequence to a user in real time through an interactive interface, wherein the waveform reconstruction is realized by adopting a waveform interpolation method.

When the method is actually applied, the data acquisition module is used for acquiring the fluctuation array, the acquired data comprises the fluctuation pressure and the waveform characteristic, the fluctuation period is in seconds, the fluctuation pressure is in microseconds, the two fluctuation curves are peeled off according to the difference of the fluctuation pressure and the waveform characteristic, the waveform height threshold value for automatic waveform encryption can be set, and when the calculated effective waveform height is larger than the waveform height threshold value, the status lamp 4 can flash to prompt that the acquired fluctuation pressure can cause the wellhead pressure to be excessively high. The waveform measurement is based on converting the actually measured pressure wave surface into a surface waveform, and in order to obtain each element of the surface waveform, the pressure spectrum is converted into the surface spectrum at the low frequency side, so that the waveform characteristics displayed by the fluctuation pressure can be conveniently extracted;

the high-frequency pressure sensor 6 receives the shut-in fluctuation pressure 19, then carries on the data processing to the waveform data collected through the single-chip microcomputer 9, turn into the discrete digital sequence and is captured, stored in the data storage module 8, can upload to the data processing system 18, utilize the data processing system 18 to process and calculate the waveform data after turning into, including waveform reconstruction and waveform parameter measurement, the waveform processing adopts the method of waveform interpolation to realize the waveform reproduction, the invention adopts the processing method of sinusoidal interpolation, its principle is to utilize mathematical processing, calculate out the result in the interval of actual sample point, can also obtain the internal each point data of the sample interval while expanding the collection interval, realize the waveform reproduction that the bending curvature characteristic is more obvious.

The data storage module 8 can store the pressure data monitored by the high-frequency pressure sensor 6 so as to be uploaded to the data processing system 18, the data processing system 18 can display the pressure data monitored by the high-frequency pressure sensor 6 and the converted waveform characteristic curve in real time through a display, so that the traceability of the data is improved, the relation between the two curves is analyzed, and the status lamp 4 can flash when the fluctuation pressure is too high;

well shut-in operations in oil and gas well production can bring about changes in wellhead pressure, mainly resulting from water hammer pressure and well shut-in pressure recovery. The water hammer pressure can cause the instantaneous increase of the wellhead pressure of the shut-in well, and the effect of the recovery of the shut-in well pressure on the increase of the wellhead pressure is continuously increased along with the time. For gas wells, the well shut-in water hammer effect is related to gas compressibility. The impact effect of well shut-in is the abrupt change of flow near the well mouth, and the impact of gas to the well mouth valve due to the inertia effect, the gas compressibility and the impact to the valve make the well mouth pressure rise rapidly. After the well is shut in, the water hammer wave propagates downwards, and the wave reflection is caused when the water hammer wave reaches the bottom of the well. Expansion of the bottom hole fluid back into the formation and tubing may also be caused when the well is shut in too quickly. Such pressure waves gradually decay to disappear during propagation due to gas friction losses, incomplete elasticity with the pipe wall, etc.

When the well is closed in an emergency, the water hammer pressure monitoring and calculating model is as follows under the condition of not considering the expansion of the oil pipe and the temperature change of the well shaft:

Ph＝ρcv0

wherein: ph is the water hammer pressure, MPa; ρ is wellbore fluid density, kg/m3; v0 is the flow rate of the well bore fluid before shut-in, m/s; and c is the pressure propagation speed, m/s.

By adopting the monitoring method, the fluctuation frequency information can be separated from the monitored fluctuation pressure data, so that the corresponding fluctuation frequency can be analyzed while the fluctuation pressure change rule is collected.

For the foregoing method embodiments, for simplicity of explanation, the methodologies are shown as a series of acts, but one of ordinary skill in the art will appreciate that the present invention is not limited by the order of acts, as some steps may, in accordance with the present invention, occur in other orders or concurrently. Further, those skilled in the art will also appreciate that the embodiments described in the specification are all preferred embodiments, and that the acts and modules referred to are not necessarily required for the present invention.

It should be noted that in other embodiments of the present invention, the method may further obtain a new method for monitoring pressure fluctuation of the water hammer effect of the well shut-in by combining one or more of the above embodiments, so as to implement analysis and application of the pressure fluctuation influence of the water hammer effect of the well shut-in scene.

It should be noted that, based on the method in any one or more of the foregoing embodiments of the present invention, the present invention further provides a storage medium, where a program code capable of implementing the method in any one or more of the foregoing embodiments is stored, where the code, when executed by an operating system, is capable of implementing the method for monitoring high-frequency pressure fluctuation based on the water hammer effect of shut-in as described above.

It is to be understood that the disclosed embodiments are not limited to the specific structures, process steps, or materials disclosed herein, but are intended to extend to equivalents of these features as would be understood by one of ordinary skill in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.

Although the embodiments of the present invention are described above, the embodiments are only used for facilitating understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is still subject to the scope of the appended claims.

Claims (13)

1. A high frequency pressure fluctuation monitoring device for well shut-in water hammer effect, the device comprising:

the pressure fluctuation acquisition module is fixedly arranged on the inner side of the wellhead casing wall and is used for acquiring pressure fluctuation signals of wellhead fluid in real time, and comprises a high-frequency pressure sensor and a pressure wave receiving window which is integrated with the high-frequency pressure sensor;

the data acquisition and processing module is arranged on the outer side of the casing wall of the wellhead, is in communication connection with the high-frequency pressure sensor and is used for converting, analyzing, storing and externally displaying pressure fluctuation signals;

the data acquisition and processing module comprises a metal shell, a data acquisition module, a data storage module, a singlechip and a built-in power supply.

2. The apparatus of claim 1, wherein the high frequency pressure sensor is an absolute pressure sensor that prevents interference with fluid pressure signal acquisition by atmospheric pressure.

3. The apparatus of claim 1, wherein the pressure fluctuation acquisition module further comprises a detection protective cover, the open end of which is fixedly connected with the inner side of the wellhead casing wall to form a space for wrapping the high-frequency pressure sensor inside.

4. The apparatus of claim 1, wherein the pressure wave receiving windows are located on both sides of the protective cover along the bottom of the well, and wherein the pressure of the fluid is monitored by the sensor after passing through the pressure wave receiving windows, effective to mitigate the direct impact of the fluid pressure on the high frequency pressure sensor.

5. The device according to claim 1, wherein the metal casing of the data acquisition and processing module is connected with the wellhead casing wall, a through hole for connecting a high-frequency pressure sensor is reserved near the top end of the wellhead casing wall, and the output end of the high-frequency pressure sensor penetrates through the top end of the metal casing and is connected with the data acquisition module.

6. The device of claim 1, wherein the metal casing is fixedly arranged on the wellhead casing wall by adopting a flange, the top end of the metal casing is positioned on the inner side of the wellhead casing wall, a fixed connecting flange is arranged on the outer side of the wellhead casing wall, a movable connecting flange is arranged on the metal casing, the bottom end of the fixed connecting flange is fixedly connected with the top end of the movable connecting flange by a connecting bolt, and the movable connecting flange can slide outside the metal casing and can be flexibly adjusted according to the thickness of the wellhead casing wall.

7. The apparatus of claim 1, wherein the data acquisition module is controlled by the single-chip microcomputer to record a fluctuating pressure value in a period of every microsecond, generate a group of fluctuating waveform data in a period of every second, and transmit the fluctuating waveform data to the single-chip microcomputer.

8. The apparatus of claim 1, wherein the data acquisition module is configured to:

converting the measured pressure wave surface into a surface waveform; pressure spectrum conversion is applied on the low frequency side to obtain a surface spectrum so as to extract waveform characteristics of a waveform corresponding to the fluctuating pressure.

9. The device of claim 1, wherein the bottom end of the metal casing of the data acquisition and processing module, which is far from the wellhead casing wall, is provided with a status light and a convenience switch.

10. The device of claim 1, wherein the single chip microcomputer is configured to strip two fluctuation curves according to different fluctuation pressures and waveform characteristics, and further identify a time when an effective wave height is greater than a threshold value based on a preset waveform automatic encryption wave height threshold value, generate corresponding prompt information, and control the state lamp to be turned on.

11. The device of claim 1, wherein the bottom end of the metal casing of the data acquisition and processing module far away from the wellhead casing wall is further provided with an external interface, one end of the external interface is connected with the single chip microcomputer, and the other end of the external interface is connected with an external data processing system and is used for transmitting pressure fluctuation data, waveform data and identification result information.

12. A method for monitoring high-frequency pressure fluctuation based on a shut-in water hammer effect, the method comprising:

when the time interval to be detected of the shut-in well is determined, starting the high-frequency pressure fluctuation monitoring device of the shut-in well water hammer effect;

the singlechip controls the data acquisition module to acquire a real-time fluctuation pressure value according to each micro period, and converts the actually measured pressure wave surface into a surface waveform according to each second period;

applying a pressure spectrum at a low frequency side so as to obtain a surface spectrum through conversion, and further extracting waveform characteristics of waveforms corresponding to the fluctuation pressure;

converting the acquired waveform characteristic data into a discrete digital sequence by utilizing a singlechip, and storing or uploading the discrete digital sequence to an external data processing system;

the data processing system carries out waveform reconstruction and waveform parameter measurement on the converted waveform corresponding digital sequence, and displays the waveform to a user in real time through an interactive interface, wherein the waveform reconstruction is realized by adopting a waveform interpolation method.

13. A storage medium having stored thereon program code for implementing the method of claim 12.