A method and apparatus for early detection of overflows based on pressure waves

Abstract

The present application belongs to the field of petroleum drilling engineering, and discloses a kind of overflow early monitoring method and device based on pressure wave, to improve the timeliness of drilling overflow monitoring.The method comprises setting initial amplitude value and initial frequency of pressure wave for implementing monitoring;Actual back pressure of wellhead return mud is detected based on the actual back pressure of wellhead return mud, and the back pressure frequency of wellhead actual back pressure pressure wave is determined based on the actual back pressure;Wellbore annulus pressure information of well bottom is collected in real time;Wellbore annulus pressure information is uploaded to the ground to generate ground signal;Downhole monitoring frequency is determined based on ground signal;Whether overflow occurs is determined based on the comparison of back pressure frequency and downhole monitoring frequency.The method and device of the present application can discover overflow earlier, and provide more time for overflow treatment.

Description

Technical Field

[0001] This invention relates to the field of oil drilling engineering, and in particular to a method and device for early monitoring of overflows based on pressure waves. Background Technology

[0002] During drilling, wellbore invasion and overflows require real-time monitoring and early detection. If overflows are not detected and addressed promptly, they can escalate into blowouts, seriously threatening well control safety and even causing severe accidents. Therefore, accurate and early detection of overflows during drilling and timely warnings are crucial.

[0003] Currently, the main methods for monitoring drilling overflows include mud tank level monitoring, outlet return flow monitoring, wellhead ultrasonic monitoring, and downhole pressure monitoring.

[0004] Monitoring the liquid level in mud tanks is convenient to implement, but this method has low monitoring accuracy, and the detection of overflow requires the return of a certain amount of mud, resulting in low timeliness.

[0005] Patent CN109751045A discloses a method and device for monitoring overflow leakage in wells. The device includes a well outlet flow rate monitoring unit and a well inlet flow rate monitoring unit. The monitoring method generally includes monitoring the instantaneous outlet flow rate, calculating the cumulative outlet volumetric flow rate, monitoring the instantaneous inlet flow rate, calculating the cumulative inlet flow rate, calculating the warning value, and triggering the warning. This outlet return flow rate monitoring method has the advantage of high monitoring accuracy; however, it still requires a certain change in the return flow rate and the fluid entering the wellbore to be close to the wellhead for detection. While its timeliness and accuracy are higher than mud tank level monitoring, there is still significant room for improvement.

[0006] Patent CN109386279A discloses a method and system for detecting gas intrusion in wellbore. The method includes: acquiring the current drilling fluid discharge rate during drilling and an ultrasonic detection waveform detected from the drilling fluid return line at the current drilling fluid discharge rate; determining an ultrasonic reference waveform based on the current drilling fluid discharge rate; comparing the ultrasonic detection waveform with the ultrasonic reference waveform; and determining whether gas intrusion has occurred in the wellbore based on the comparison result. However, the ultrasonic monitoring signal at the wellhead is prone to attenuation, has a limited propagation distance, and is limited to relatively shallow well depths.

[0007] Patent CN109577891A discloses a method for monitoring overflow in deepwater oil and gas wells. The steps are as follows: pressure sensors are installed at equal intervals on the riser according to the water depth to measure the pressure of the circulating fluid in the riser in real time. The pressure information measured by the pressure sensors is then transmitted in real time to the surface control system. The surface system processes and analyzes the measurement information from the pressure sensors in the riser section to obtain the pressure difference between two adjacent sensors. The surface system calculates the pressure difference between two adjacent sensors by using the drilling fluid flow rate pumped into the wellhead and combining it with the flow-pressure difference relationship. The pressure difference measured by the pressure sensors is compared in real time with the pressure difference calculated based on the flow-pressure difference relationship, enabling overflow monitoring and identification in the riser, issuing alarms, and providing reasonable well control measures. However, this downhole pressure monitoring requires a significant intrusion of formation fluid into the wellbore, causing a noticeable change in bottom hole pressure, which limits its monitoring conditions and makes it difficult to detect minute overflows.

[0008] Therefore, existing drilling boil monitoring methods all have certain limitations and constraints, especially in early monitoring, which still has significant shortcomings. Thus, it is essential to research an early monitoring method and device for drilling boils to improve the timeliness of monitoring, enabling earlier detection and providing more time for boil remediation. Summary of the Invention

[0009] To address the above problems, the present invention provides a method and apparatus for early overflow monitoring based on pressure waves.

[0010] According to one aspect of the present invention, a method for early overflow monitoring based on pressure waves is provided, the method comprising the following steps: Set the initial amplitude and initial frequency of the pressure wave used for monitoring; The back pressure of the wellhead return mud is controlled according to the initial amplitude and initial frequency of the pressure wave set, and the actual back pressure of the wellhead return mud is detected. Based on the actual back pressure, the back pressure frequency of the actual back pressure wave at the wellhead is determined. Real-time collection of wellbore annular pressure information at the bottom of the well; The wellbore annular pressure information is uploaded to the ground to generate a ground signal; The downhole monitoring frequency is determined based on the surface signals; Whether an overflow has occurred is determined by comparing the back pressure frequency and the downhole monitoring frequency.

[0011] According to one embodiment of the present invention, the initial wave amplitude value is set such that the peak value of the bottom hole pressure wave is less than the formation leakage pressure.

[0012] According to one embodiment of the present invention, the initial amplitude value is set such that the amplitude of the bottom hole pressure wave is greater than the threshold of the peak that the instrument used to collect the wellbore annular pressure information in real time can recognize.

[0013] According to one embodiment of the present invention, the initial frequency is set to be less than the critical frequency value for accurate measurement and detection by the instrument used to collect the annular pressure information of the wellbore in real time, and to avoid the disturbance frequency generated by the rotation of the drill string.

[0014] According to one embodiment of the present invention, the method further includes processing the wellbore annulus pressure information before uploading the wellbore annulus pressure information to the surface.

[0015] According to one embodiment of the present invention, the wellbore annulus pressure information uploaded to the ground includes pressure wave frequencies obtained based on the analysis of the wellbore annulus pressure information collected in real time.

[0016] According to one embodiment of the present invention, determining whether a overflow has occurred based on a comparison between the back pressure frequency and the downhole monitoring frequency includes: If the difference between the downhole monitoring frequency and the back pressure frequency is within a preset range, it is determined that no well invasion or overflow has occurred. If the difference between the downhole monitoring frequency and the back pressure frequency exceeds the preset range, well invasion or overflow is determined to have occurred.

[0017] According to one embodiment of the present invention, the degree of overflow is determined based on the difference between the downhole monitoring frequency and the back pressure frequency.

[0018] According to one embodiment of the present invention, when it is determined that well invasion or overflow has occurred, the larger the difference, the higher the degree of overflow.

[0019] According to one embodiment of the present invention, after determining the initial amplitude value of the pressure wave used for monitoring, the amplitude value is evaluated to determine whether it meets the set conditions.

[0020] According to another aspect of the present invention, a pressure wave-based overflow early monitoring device is provided, the device comprising: A pressure wave setting device, which sets the initial amplitude and initial frequency of the pressure wave to be monitored; The pressure wave generating device controls the back pressure of the wellhead return mud according to the initial amplitude and initial frequency of the pressure wave set by the pressure wave setting device. The wellhead pressure wave detection device detects the actual back pressure of the mud returning from the wellhead. Downhole pressure wave detection device, which collects wellbore annular pressure information at the bottom of the well in real time; A downhole pressure wave uploading device is communicatively connected to the downhole pressure wave detection device and uploads the wellbore annular pressure information to the surface to generate a surface signal; A ground information monitoring device that detects the ground signal and determines the downhole monitoring frequency based on the ground signal; The real-time analysis device is communicatively connected to the wellhead pressure wave detection device and the surface information monitoring device. It receives the actual back pressure and the downhole monitoring frequency, analyzes the actual back pressure to determine the back pressure frequency of the actual back pressure wave at the wellhead, and determines whether an overflow has occurred based on the comparison between the back pressure frequency and the downhole monitoring frequency.

[0021] According to one embodiment of the present invention, the pressure wave generating device is an automatic throttling manifold, which automatically adjusts the throttling valve opening according to the initial amplitude and initial frequency of the pressure wave, and controls the back pressure to change according to preset data.

[0022] According to one embodiment of the present invention, the downhole pressure wave uploading device is a measurement while drilling instrument that communicates via mud pulses.

[0023] According to one embodiment of the present invention, the apparatus further includes an evaluation device, which includes an evaluation model. The evaluation model evaluates the initial amplitude value of the pressure wave to determine whether the amplitude value of the pressure wave causes the peak value of the bottom hole pressure wave to be less than the formation leakage pressure and the amplitude of the bottom hole pressure wave to be greater than the threshold value of the peak value that the downhole pressure wave detection device can identify.

[0024] According to one embodiment of the present invention, the real-time analysis device is configured as follows: Based on the fact that the difference between the downhole monitoring frequency and the back pressure frequency is within a preset range, it is determined that no well invasion or overflow has occurred; Well invasion and overflow are determined to have occurred based on the difference between the downhole monitoring frequency and the back pressure frequency exceeding the preset range.

[0025] By adopting the above technical solutions, the pressure wave-based early overflow monitoring method and device provided by the present invention utilizes the principle that pressure waves propagate at different speeds in different media, takes the pressure wave with reduced signal attenuation as the monitoring object, and compares the frequency of the bottom hole pressure wave signal with the frequency of the surface input pressure wave to achieve timely and accurate early overflow monitoring, thereby improving the timeliness and adaptability of drilling overflow monitoring. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 A flowchart of a pressure wave-based early overflow monitoring method according to an embodiment of the present invention is shown; Figure 2A flowchart illustrating the preparatory work for setting a pressure wave according to an embodiment of the present invention is shown; Figure 3 A flowchart illustrating the implementation of monitoring according to an embodiment of the present invention is shown; Figure 4 Operating status diagram of the overflow early monitoring device based on pressure waves; Figure 5 A comparative diagram showing the transmission of pressure waves from the wellhead to the bottom of the well according to an embodiment of the present invention is shown. Figure 6 An application example diagram of a pressure wave-based early overflow monitoring method according to an embodiment of the present invention is shown. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] The terms "comprising" and "having," and any variations thereof, used in the specification and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0029] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] Pressure waves propagate at different speeds in different media. When a blowout occurs during drilling, formation fluids invade the wellbore. Before the contaminated mud, a mixture of formation fluids and drilling mud, returns to the wellhead, the upper part of the wellbore is typically pure drilling mud, while the lower part is contaminated mud mixed with formation fluids. The propagation speed of pressure waves in pure drilling mud is greater than that in gas-liquid two-phase flow or low-density liquids. After the pressure wave propagates from pure drilling mud to the contaminated mud mixed with formation fluids, its speed decreases and its frequency increases. This invention utilizes this principle. By monitoring the frequency changes of the pressure wave at the bottom of the well and comparing it with the frequency of the pressure wave input from the surface, it can determine whether gas or liquid exists in the lower part of the wellbore, thereby achieving early prediction of a blowout.

[0031] This invention uses pressure waves instead of ultrasound. This is because, firstly, ultrasonic monitoring signals are prone to attenuation, have limited propagation distance, and are limited to shallow well depths; secondly, the propagation of ultrasound in drilling mud is affected by factors such as the type and density of the medium, ambient temperature, and pressure, resulting in poor measurement accuracy and stability. Furthermore, using ultrasound for monitoring requires a separate dedicated ultrasonic transmitter and receiver, increasing costs.

[0032] One objective of this invention is to provide a method for early overflow monitoring based on pressure waves. For example... Figure 1 As shown, the method generally includes: Step S1: Set the initial amplitude and initial frequency of the pressure wave used for monitoring; Step S2: Control the back pressure of the wellhead return mud according to the initial amplitude and initial frequency of the set pressure wave and detect the actual back pressure of the wellhead return mud. Determine the back pressure frequency of the actual back pressure wave based on the actual back pressure. Step S3: Collect annular pressure information at the bottom of the well in real time; Step S4: Upload the wellbore annulus pressure information to the ground to generate a ground signal; Step S5: Determine the downhole monitoring frequency based on the ground signal; Step S6: Determine whether a overflow has occurred based on a comparison of the back pressure frequency and the downhole monitoring frequency.

[0033] The pressure wave-based early overflow monitoring method provided by this invention utilizes the principle that pressure waves propagate at different speeds in different media. It uses pressure waves with reduced signal attenuation as the monitoring object and compares the frequency of the bottom hole pressure wave signal with the frequency of the surface input pressure wave to achieve timely and accurate early overflow monitoring, thereby improving the timeliness and adaptability of drilling overflow monitoring.

[0034] This invention achieves early overflow prediction by monitoring the frequency of pressure waves. Compared to methods that monitor the phase shift curve or time difference of the wave, this invention is more operable. When using the phase shift curve or time difference of the wave as a comparison parameter for overflow monitoring, time synchronization or signal synchronization is required to obtain an ideal wellhead signal for comparison. However, in practice, achieving time synchronization or signal synchronization is very difficult. The solution of this invention compares the frequency of pressure waves, which does not require signal synchronization and is easier to implement.

[0035] The following provides a detailed explanation of each step of the above method using examples.

[0036] In step S1, the initial amplitude and frequency of the pressure wave used for monitoring are set. The main characteristics of the wellhead backpressure wave signal include the pressure wave amplitude ΔP and frequency Fs. Setting appropriate pressure wave amplitude ΔP and frequency Fs ensures that subsequent monitoring can be successfully implemented.

[0037] In some embodiments, the set pressure wave amplitude ΔP and frequency Fs need to meet certain conditions. For example, the amplitude of the pressure wave used for monitoring needs to be set such that the peak value of the bottom hole pressure wave is less than the formation leakage pressure, so as to avoid formation leakage caused by the application of the pressure wave. In addition, the amplitude of the pressure wave used for monitoring also needs to be set such that the bottom hole pressure wave amplitude is greater than the threshold of the peak value that the measuring instrument used to collect real-time wellbore annular pressure information can recognize, so that the bottom hole measuring instrument can recognize the test wave.

[0038] Therefore, before actually applying and controlling the pressure wave, it is advisable to assess whether the set wave amplitude value meets the specified conditions. The following section combines... Figure 2 The flowchart shown provides a detailed illustrative example of the preparatory work for setting up the pressure wave.

[0039] Based on the amplitude value ΔP and the basic wellhead pressure P0, the peak value of the wellhead back pressure wave Pwhp can be determined using the following formula: Pwhp=P0+ΔP.

[0040] The basic wellhead pressure P0 can be determined based on drilling engineering design data and field-collected technical data. The amplitude value ΔP is an empirically estimated value based on the analysis of drilling engineering design data and field-collected technical data. When the amplitude value ΔP is deemed appropriate, the calculated peak value Pwhp of the wellhead back pressure wave can be used as a reference parameter for implementing pressure wave control.

[0041] Generally, when the back pressure wave from the wellhead reaches the bottom of the well, the signal amplitude will attenuate. The attenuation coefficient η of the transmitted pressure wave signal can be calculated using a wellbore mud pulse signal attenuation prediction model. The specific calculation formula is as follows:

[0042] In the formula, Q — Mud pump displacement, m 3 / s; ρ —Drill mud density, kg / m³ 3 ; μ — Mud viscosity, mPa·s; α L —— Mud solid content, dimensionless; r —— Particle size of mud solid material, m; H —— Well depth, m; A —— Flow area of the drill string nozzle, m 2 ; T —— Period of the mud pressure wave signal measured while drilling, s; The signal frequency is 1 / T; θ —— Well deviation angle, °; η —— Signal attenuation coefficient, dB·m -1 .

[0043] According to the signal attenuation coefficient η of the pressure wave and the wave amplitude ΔP, the wave amplitude Pba (bottomhole pressure wave amplitude) of the bottomhole pressure wave can be determined as: .

[0044] Furthermore, based on the wave amplitude Pba of the bottomhole pressure wave and the basic bottomhole pressure Pwb, the wave peak value Pwbp (wave peak of wellbottom pressure) of the bottomhole pressure wave can be determined. The specific calculation formula is: Pwbp = Pwb + Pba.

[0045] The basic bottomhole pressure Pwb can be determined according to the drilling engineering design data and the technical data collected on site.

[0046] Furthermore, the safe pressure window of the drilling formation can be determined according to the drilling engineering design data and the technical data collected on site, that is, between the formation pressure Pf (formation pressure) and the formation leakage pressure Pl (formation leakage pressure). It should be ensured that the wave peak value Pwbp of the bottomhole pressure wave is less than the formation leakage pressure Pl, that is, Pwbp < Pl. At the same time, in order to enable the bottomhole real-time measurement instrument to identify and collect the pressure wave signal, it is necessary to ensure that the wave amplitude Pba of the bottomhole pressure wave is greater than the threshold value Pd of the wave peak recognized by the real-time measurement instrument, that is, Pba > Pd. When the set wave amplitude ΔP meets these two conditions, it means that the wave amplitude ΔP is appropriate.

[0047] In some embodiments, the initial frequency is set to be lower than the critical frequency for accurate measurement and detection by instruments used to collect real-time wellbore annular pressure information, and to avoid the disturbance frequency caused by drill string rotation. For example, the initial frequency is defined based on the available pressure wave range, including that the initial frequency should be lower than the upper limit of the pressure wave frequency generated by the throttle valve auto-regulation response, avoid the disturbance frequency caused by drill string rotation, and be lower than the critical frequency attenuation of the pressure wave propagating in the wellbore annulus that would prevent downhole instruments from accurately measuring and detecting it. The higher the pressure wave frequency, the faster the amplitude attenuates during propagation. To reduce signal attenuation, the pressure wave frequency should be as low as possible while still being detectable. Preferably, the pressure wave frequency should keep the throttle valve drive mechanism within its effective load range.

[0048] Once the appropriate wave amplitude ΔP and frequency Fs are determined, the specific pressure wave adjustment value and adjustment period can be further determined, thus completing the preparatory work.

[0049] Next, we will enter the real-time monitoring phase. Please refer to [link / reference] for details. Figure 1 and Figure 3 .

[0050] In step S2, the back pressure of the mud returned from the wellhead is controlled to change according to the initial amplitude and initial frequency of the pressure wave set, and the actual back pressure of the mud returned from the wellhead is detected. Based on the actual back pressure, the back pressure frequency of the actual back pressure wave at the wellhead is determined.

[0051] Combination Figure 4 The diagram illustrating the usage status of a pressure wave-based overflow early monitoring device according to an embodiment of the present invention serves as an example of this control operation.

[0052] Real-time monitoring is required during drilling or circulation operations, where mud flows from the mud tank through the mud pump, through the riser, into the drill string, flows into the annulus at the bottom of the well, and then returns from the annulus to the wellhead. The mud then exits from the wellhead of the rotary control device and enters the mud tank through the automatic choke manifold.

[0053] The back pressure of the mud can be changed by altering and adjusting the opening of the choke valve in the automatic choke manifold. The peak value Pwhp of the wellhead back pressure wave can be determined based on the amplitude value ΔP set in step S1. The pressure value of the pressure wave at each moment can be determined based on the peak value Pwhp and the frequency Fs. The opening of the choke valve can then be controlled based on this pressure wave.

[0054] Pressure sensors can be installed on automatic choke manifolds to measure wellhead back pressure in real time. Based on the measured wellhead back pressure, the actual wellhead back pressure wave and its frequency Fr can be determined. The measured wellhead back pressure wave can also be filtered and detected to obtain the actual wellhead back pressure wave's width Prw, frequency Fr, and amplitude data Prpa.

[0055] The pressure wave generated by the automatic choke manifold is transmitted through the drilling mud to the annulus, forming an annular pressure wave that continues to propagate downwards to near the bottom of the well. If a spill occurs at the bottom of the well, formation fluids intrude into the wellbore, and the lower part consists of contaminated drilling mud mixed with formation fluids. The pressure wave propagates faster in pure drilling mud than in gas-liquid two-phase flow or low-density liquids. After propagating from pure drilling mud to the contaminated drilling mud mixed with formation fluids, the pressure wave velocity decreases and the frequency increases.

[0056] Therefore, in step S3, the annular pressure information at the bottom of the well is collected in real time. For example, the annular pressure can be measured in real time using a pressure sensor in a downhole real-time measurement instrument. Optionally, the real-time measured pressure data can be filtered in real time by a signal processing module to eliminate interference signals, and the detection module can monitor the processed data in real time to obtain information such as wave width, frequency, and signal strength. After determining this information, the monitored pressure wave frequency and amplitude data can be transmitted to the downhole information uploading instrument.

[0057] In step S4, the wellbore annular pressure information is uploaded to the surface, generating a surface signal. For example, a measurement-while-drilling (MWD) instrument that communicates via mud pulses can be used to include the predicted overflow data in the MWD upload data sequence, and then the data is uploaded to the surface via mud pulses through the circulating mud in the drill string.

[0058] In step S5, the downhole monitoring frequency is determined based on the surface signal. For example, the mud pulse upload pressure signal can be collected by a pressure sensor on the riser, and the upload information can be decoded to obtain the real-time downhole monitoring frequency F. T .

[0059] In step S6, based on the back pressure frequency Fr and the downhole monitoring frequency F T The comparison determines whether an overflow has occurred.

[0060] For example, if the difference between the downhole monitoring frequency and the back pressure frequency is within a preset range ΔFv, then it is determined that no wellbore intrusion or overflow has occurred; if the difference exceeds the preset range ΔFv, then it is determined that wellbore intrusion or overflow has occurred. Ideally, if there is no wellbore intrusion or overflow, the downhole monitoring frequency F... T The downhole monitoring frequency Fr should be equal to the back pressure frequency Fr. However, due to some interference in the actual operating environment, even without well invasion or overflow, the downhole monitoring frequency Fr may be different. TThere may also be some deviation from the back pressure frequency Fr. Therefore, if the difference between the two is within the preset range ΔFv, they can be considered to be basically equal, corresponding to no well invasion or overflow. However, if the difference exceeds the preset range ΔFv, it is no longer a frequency deviation caused by environmental interference, but rather because the occurrence of well invasion or overflow has led to significant changes in the wave velocity and frequency of the pressure wave in the gas-liquid two-phase flow and low-density liquid. In this case, well invasion or overflow is confirmed. The specific preset range ΔFv can be determined based on factors such as drilling fluid density, rheological parameters, and drill string rotation.

[0061] If well invasion or overflow is confirmed, the downhole monitoring frequency F can also be used as a reference. T The difference ΔF between the back pressure frequency Fr and the back pressure frequency Fr (ΔF=F) T -Fr) determines the degree of overflow. The larger the ΔF value, the higher the degree of overflow.

[0062] Another object of the present invention is to provide an early overflow monitoring device based on pressure waves. For example... Figure 4 As shown, the device generally includes: The pressure wave setting device sets the initial wave amplitude ΔP and initial frequency Fs of the pressure wave to be monitored. The pressure wave generator 10 controls the back pressure of the wellhead return mud according to the initial wave amplitude ΔP and initial frequency Fs of the pressure wave set by the pressure wave setting device. Wellhead pressure wave detection device 20 detects the actual back pressure of the mud returning from the wellhead. The downhole pressure wave detection device 30 collects annular pressure information at the bottom of the well in real time. The downhole pressure wave uploading device 40 is communicatively connected to the downhole pressure wave detection device 30 and uploads the wellbore annulus pressure information to the surface to generate a surface signal; Ground information monitoring device 50 detects ground signals and determines the downhole monitoring frequency F based on the ground signals. T ; The real-time analysis device 60 is communicatively connected to the wellhead pressure wave detection device 20 and the surface information monitoring device 50, receiving the actual back pressure and the downhole monitoring frequency F. T The actual back pressure is analyzed to determine the back pressure frequency Fr of the actual back pressure wave at the wellhead, and the back pressure frequency Fr is used as the basis for the downhole monitoring frequency F. T The comparison determines whether an overflow has occurred.

[0063] In some embodiments, the pressure wave setting device and the real-time analysis device 60 can be the same device, which can be a computer storing relevant models. For example, these models may include models for setting and evaluating the initial wave amplitude value ΔP, and models for analyzing and comparing the back pressure frequency Fr and the downhole monitoring frequency F. T This leads to an analytical model that determines whether an overflow has occurred.

[0064] In some embodiments, the pressure wave generator 10 may specifically be an automatic choke manifold already included in the drilling system. The back pressure of the drilling mud is changed by altering and adjusting the opening of the choke valve of the automatic choke manifold.

[0065] In some embodiments, the wellhead pressure wave detection device 20 may employ a pressure sensor installed on an automatic choke manifold. This pressure sensor can measure the wellhead back pressure in real time, and can also perform filtering and detection to obtain the actual wellhead back pressure wave width Prw, frequency Fr, and amplitude data Prpa. This data can be transmitted to the real-time analysis device 60.

[0066] In some embodiments, the downhole pressure wave detection device 30 may employ a pressure sensor included in a downhole real-time measurement instrument. This pressure sensor can measure pressure data in real time, filter and eliminate interference signals in real time through a signal processing module, and monitor the processed data in real time through a detection module to obtain information on wave width, frequency, and signal strength. It can also transmit the monitored pressure wave frequency and amplitude data to the downhole pressure wave uploading device 40.

[0067] In some embodiments, the downhole pressure wave uploading device 40 can employ a MWD-compatible uploading instrument. The collected downhole pressure wave data can be included in the MWD uploading data sequence and uploaded to the surface via drilling mud in the form of mud pulses. Mud pulse communication enables long-distance data transmission, allowing the surface monitoring system to acquire various downhole parameters and status information in real time, thereby making timely and accurate decisions.

[0068] In some embodiments, the ground information monitoring device 50 may employ a pressure sensor installed on the riser, which collects mud pulse transmission pressure signals, decodes them to obtain transmission information, and obtains the real-time monitoring frequency F. T .

[0069] In some embodiments, as described above, the real-time analysis device 60 can be a computer internally storing a model for determining whether an overflow has occurred, and configured as follows: The absence of well invasion or overflow is determined based on the difference between the downhole monitoring frequency and the back pressure frequency being within a preset range. Well invasion and overflow are determined to have occurred based on the difference between the downhole monitoring frequency and the back pressure frequency exceeding the preset range.

[0070] If well invasion or overflow is confirmed, the real-time analysis device 60 can further predict the severity of the overflow. For example, based on the downhole monitoring frequency F... T The difference ΔF between the back pressure frequency Fr and the back pressure frequency Fr (ΔF=F) T -Fr) determines the degree of overflow. The larger the ΔF value, the higher the degree of overflow.

[0071] Optionally, the pressure wave-based early overflow monitoring device according to the present invention may further include an evaluation device, which includes an evaluation model. The evaluation model evaluates a set initial amplitude value of the pressure wave to determine whether the amplitude value of the pressure wave results in a bottomhole pressure wave peak value less than the formation leakage pressure and a bottomhole pressure wave amplitude greater than a threshold value that the downhole pressure wave detection device can identify. The evaluation device can also be implemented by a computer.

[0072] Many components of the pressure wave-based early overflow monitoring device of the present invention can utilize existing equipment in the drilling system, saving the cost of device construction.

[0073] The invention will now be illustrated with a specific application example.

[0074] A certain well is 6000m deep, and the mud concentration is 1.99g / cm³. 3 The well has a solid particle content of 60%, an average solid particle size of 5 mm, a plastic viscosity of 45 mPa·s, a dynamic shear rate of 5 Pa, a displacement of 32 L / s, a 5-inch drill string, a 244.5 mm casing extending from the surface to 4500 m, and a drill bit diameter of 215.9 mm. Taking this well as an example, the specific implementation process of the pressure wave-based early overflow monitoring method according to the present invention is introduced.

[0075] The implementation of an early overflow monitoring method based on pressure waves is mainly divided into a preparation stage and a real-time monitoring stage.

[0076] (1) Preparation stage The main characteristics of the wellhead backpressure wave signal include the pressure wave amplitude ΔP and frequency Fs. ΔP = 1 MPa and frequency Fs = 0.1 Hz are set, and the preset range of the frequency difference between well invasion and overflow is determined to be 0.02 Hz.

[0077] The basic wellhead pressure for back pressure is 0.4 MPa, and the peak pressure wave Pwhp = P0 + ΔP = 0.4 + 1 = 1.4 MPa.

[0078] The back pressure wave from the wellhead is transmitted to the bottom of the well; the attenuation coefficient of the transmitted pressure wave signal is calculated. η= 0.0005038591dB·m -1The calculated bottom hole pressure wave amplitude is Pba = 0.46 MPa, and the bottom hole pressure wave peak value is Pwbp = Pwb + Pba = 0.46 + 92.84 = 93.30 MPa.

[0079] The drilling formation safety pressure window, determined based on drilling engineering design data and on-site technical data, is namely, formation leakage pressure P1 = 101.5 MPa and formation pressure Pf = 92.5 MPa.

[0080] If the threshold Pd for identifying wave peaks using real-time measuring instruments is 0.2 MPa, and the calculated bottom hole pressure wave peak value of 93.30 MPa is less than the formation leakage pressure of 101.5 MPa and the bottom hole pressure wave amplitude of 0.46 MPa is greater than the threshold of 0.2 MPa for identifying wave peaks using real-time measuring instruments, then the evaluation data settings meet the conditions and real-time monitoring can be achieved.

[0081] Therefore, the pressure regulation value of the automatic throttling manifold is set to ΔP=1MPa, and the frequency is set to Fs=0.1Hz.

[0082] (2) Real-time monitoring stage Real-time monitoring is required during drilling or cyclic operations, such as... Figure 4 As shown, the mud flows from the mud tank through the mud pump, through the riser into the drill string, and then back up to the wellhead through the annulus. From the wellhead, the mud flows into the mud tank through the automatic choke manifold.

[0083] The surface automatic throttling manifold can automatically adjust the throttling valve opening according to preset data to control back pressure changes. The back pressure changes according to a preset pressure fluctuation pattern. The pressure wave signal generated on the surface is transmitted to the bottom of the well through the wellbore annulus. The pressure wave fluctuation signal attenuates as follows: Figure 5 As shown.

[0084] The downhole real-time measurement instrument measures the annular pressure in the wellbore in real time through a pressure sensor. The real-time pressure data is filtered in real time by the signal processing module to eliminate interference signals. The detection module monitors the processed data in real time to obtain information on the wave width, frequency, and signal strength. The monitoring pressure wave's wave width, frequency, and amplitude data are transmitted to the downhole information uploading instrument.

[0085] Downhole information uploading instruments can be used as uploading instruments for MWD. ​​Predicted overflow results data can be included in the MWD uploading data sequence and uploaded to the surface via mud pulses circulating in the drill string.

[0086] The surface information monitoring and decoding device collects the mud pulse transmission pressure signal through the pressure sensor on the riser, decodes it to obtain the transmission information, and obtains the real-time downhole monitoring frequency F. T .

[0087] The automatic choke manifold is equipped with a pressure sensor that can measure the back pressure signal in real time, filter and detect it to obtain the actual wellhead back pressure wave width Prw, frequency Fr, and amplitude data Prpa.

[0088] The real-time analysis module compares the downhole monitoring frequency F. T The back pressure frequency F of the actual wellhead back pressure wave r Determine if an overflow has occurred.

[0089] If the downhole monitoring frequency F T With back pressure frequency F r If the difference is within 0.02Hz, it is determined that no well intrusion or overflow has occurred; If the downhole monitoring frequency F T With back pressure frequency F r If the difference exceeds 0.02Hz, it is determined that well intrusion or overflow has occurred.

[0090] It can also be based on the frequency difference ΔF (ΔF=F). T -F r The degree of overflow is determined by the value of ΔF; the larger the ΔF value, the higher the degree of overflow.

[0091] like Figure 6 As shown, the real-time downhole monitoring frequency F obtained by surface decoding is... T and back pressure frequency F r In comparison, the downhole monitoring frequency F T The frequency increased significantly after 20 minutes of monitoring. At the 20-minute monitoring time, the downhole monitoring frequency F... T and back pressure frequency F r The difference exceeded the preset range (i.e., within 0.02Hz), indicating that formation fluid entered the wellbore at a monitoring time of approximately 20 minutes, triggering an early warning of a blowout. The figure also shows that at a monitoring time of 25 minutes, the downhole monitoring frequency F... T With back pressure frequency F r The difference was already about 0.05Hz, and the subsequent difference also increased significantly, increasing the warning overflow level.

[0092] In addition to the above-mentioned methods for determining well invasion and overflow, fuzzy mathematics methods, artificial neural networks, and other methods can be used to further optimize data analysis, improve the accuracy of data analysis and predictive adaptability.

[0093] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for early overflow monitoring based on pressure waves, characterized in that, Includes the following steps: Set the initial amplitude and initial frequency of the pressure wave used for monitoring; The back pressure of the wellhead return mud is controlled to change according to the initial amplitude and initial frequency of the pressure wave, and the actual back pressure of the wellhead return mud is detected. Based on the actual back pressure, the back pressure frequency of the actual back pressure wave at the wellhead is determined. Real-time collection of wellbore annular pressure information at the bottom of the well; The wellbore annular pressure information is uploaded to the ground to generate a ground signal; The downhole monitoring frequency is determined based on the surface signals; Whether an overflow has occurred is determined by comparing the back pressure frequency and the downhole monitoring frequency.

2. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, The initial amplitude value is set such that the peak value of the bottom hole pressure wave is less than the formation leakage pressure.

3. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, The initial amplitude value is set such that the amplitude of the bottom hole pressure wave is greater than the threshold value of the peak that the instrument used to collect the annular pressure information of the wellbore in real time can recognize.

4. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, The initial frequency is set to be lower than the critical frequency value for accurate measurement and detection by the instrument used to collect the annular pressure information of the wellbore in real time, and to avoid the disturbance frequency caused by the rotation of the drill string.

5. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, The method further includes processing the wellbore annular pressure information before uploading it to the surface.

6. The overflow early monitoring method based on pressure waves according to claim 5, characterized in that, The wellbore annulus pressure information uploaded to the ground includes pressure wave frequencies obtained from analysis based on the real-time collected wellbore annulus pressure information.

7. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, Determining whether a spill has occurred based on a comparison between the back pressure frequency and the downhole monitoring frequency includes: If the difference between the downhole monitoring frequency and the back pressure frequency is within a preset range, it is determined that no well invasion or overflow has occurred. If the difference between the downhole monitoring frequency and the back pressure frequency exceeds the preset range, well invasion or overflow is determined to have occurred.

8. The overflow early monitoring method based on pressure waves according to claim 7, characterized in that, The degree of overflow is determined based on the difference between the downhole monitoring frequency and the back pressure frequency.

9. The overflow early monitoring method based on pressure waves according to claim 8, characterized in that, In cases where well invasion or overflow is confirmed, the larger the difference, the higher the degree of overflow.

10. The overflow early monitoring method based on pressure waves according to claim 1, characterized in that, After determining the initial amplitude value of the pressure wave used for monitoring, it is evaluated whether the amplitude value meets the set conditions.

11. An early overflow monitoring device based on pressure waves, characterized in that, include: A pressure wave setting device, which sets the initial amplitude and initial frequency of the pressure wave to be monitored; The pressure wave generating device controls the back pressure of the wellhead return mud according to the initial amplitude and initial frequency of the pressure wave set by the pressure wave setting device. A wellhead pressure wave detection device, which detects the actual back pressure of the wellhead mud returning from the wellhead; Downhole pressure wave detection device, which collects wellbore annular pressure information at the bottom of the well in real time; A downhole pressure wave uploading device is communicatively connected to the downhole pressure wave detection device and uploads the wellbore annular pressure information to the surface to generate a surface signal; A ground information monitoring device that detects the ground signal and determines the downhole monitoring frequency based on the ground signal; The real-time analysis device is communicatively connected to the wellhead pressure wave detection device and the surface information monitoring device. It receives the actual back pressure and the downhole monitoring frequency, analyzes the actual back pressure to determine the back pressure frequency of the actual back pressure wave at the wellhead, and determines whether an overflow has occurred based on the comparison between the back pressure frequency and the downhole monitoring frequency.

12. The overflow early monitoring device based on pressure waves according to claim 11, characterized in that, The pressure wave generating device is an automatic throttling manifold. The automatic throttling manifold automatically adjusts the throttling valve opening according to the initial amplitude and initial frequency of the pressure wave, controlling the back pressure to change according to preset data.

13. The overflow early monitoring device based on pressure waves according to claim 11, characterized in that, The early overflow monitoring device also includes an evaluation device, which contains an evaluation model. The evaluation model evaluates the initial amplitude value of the pressure wave to determine whether the initial amplitude value of the pressure wave makes the peak value of the bottom hole pressure wave less than the formation leakage pressure and the amplitude of the bottom hole pressure wave greater than the threshold value of the peak that the downhole pressure wave detection device can identify.

14. The overflow early monitoring device based on pressure waves according to claim 11, characterized in that, The real-time analysis device is configured as follows: Based on the fact that the difference between the downhole monitoring frequency and the back pressure frequency is within a preset range, it is determined that no well invasion or overflow has occurred; Well invasion and overflow are determined to have occurred based on the difference between the downhole monitoring frequency and the back pressure frequency exceeding the preset range.

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