SYSTEM AND METHOD FOR MONITORING THE ANNEL SPACE TO DETECT MANIFESTATIONS AND ABSORPTIONS

Abstract

An annulus monitoring-based kick / loss monitoring system, comprising: an annulus monitoring assembly (107), configured to monitor annulus monitoring information at a fixed depth within a drilling annulus, wherein the annulus monitoring information comprises an annulus fluid velocity measurement value and / or fluid composition information of an annulus fluid; and a controller (101), coupled with the annulus monitoring assembly and configured to: receive the annulus monitoring information and mud logging data; determine drilling conditions associated with kick / loss monitoring; select a corresponding kick / loss monitoring model on the basis of the drilling conditions; determine a theoretical annulus fluid velocity value at a specified depth on the basis of the kick / loss monitoring model; determine whether the annulus fluid velocity measurement value falls within a predetermined range of the theoretical annulus fluid velocity value; and in response to the annulus fluid velocity measurement value deviating beyond the predetermined range of the theoretical annulus fluid velocity value, determine the presence of a kick or loss.

Description

A spill monitoring system and method based on annular space monitoring Technical Field

[0001] The present invention relates to the technical field of oil drilling, and in particular to a system, method and controller for leak monitoring and processing. Background Art

[0002] Oil and gas exploration is increasingly moving into deepwater, deep, and ultra-deep reservoirs. These reservoirs have a narrow safe density window, requiring precise control of drilling fluid density within a narrow range to ensure safe drilling operations. Furthermore, the complex geological conditions in these areas make drilling operations prone to spills. Leakage monitoring is a crucial early step in managed pressure drilling. Failure to promptly control spills can lead to blowouts.

[0003] In the prior art, the means of leak monitoring mainly adopts ground monitoring, including mud pool liquid level monitoring method, inlet and outlet flow monitoring method, vertical pressure casing pressure monitoring method, integrated logging monitoring method, etc. However, there is a delay between the occurrence of leak at the bottom of the well and the ground display, and the timeliness of the ground monitoring means is insufficient. To increase the timeliness of monitoring, downhole leak monitoring is required. Patent publication CN 103061753A discloses a device for downhole flow measurement and monitoring of early overflow while drilling. The measuring device measures downhole flow changes through an ultrasonic sensor installed in the drill collar short section. It can measure downhole flow, pressure and temperature during the drilling process to monitor early overflow, and its measurement data is uploaded in real time through the MWD connection. Patent document CN107575212B provides an ultrasonic downhole gas intrusion monitoring device and method, which includes an ultrasonic sensor for obtaining drilling status data to determine the overflow situation, and uploads the data for alarm.

[0004] The above-mentioned measurement while drilling device measures the downhole annular flow and flow change data through an ultrasonic sensor installed in the drill collar. However, during the drilling process, the drill collar rotates and moves continuously, causing the measurement position of the ultrasonic sensor to constantly change. The measured object is not stable, and is affected by downhole noise and extreme environments, resulting in insufficient accuracy of the measured data, which is prone to misjudgment. Moreover, the data measured in the drill collar is difficult to transmit to the ground in real time. Currently, downhole data is mostly transmitted using mud pulses, but the mud pulse transmission speed is very slow, and sufficient data cannot be obtained in real time. Another downhole data transmission method uses sound waves, but the underground sound environment is complex, and the sound wave signal is very susceptible to interference, making stable and accurate transmission impossible. In addition, below a certain drilling depth, the downhole fluid will be in a supercritical state, and ultrasonic sensors cannot measure the gas content in the supercritical fluid.

[0005] In addition, during the drilling process, under non-drilling conditions such as drilling, starting and stopping pumps, connecting single pipes, circulation, etc., the flow display caused by ground operations will cause false alarms in the ground leakage monitoring, reducing the effectiveness and reliability of the ground leakage monitoring means. Chinese patent publication CN101696627A discloses a method for monitoring accidents during drilling. The alarm judgment of the leakage is to monitor the abnormal changes in the total volume of mud in the circulating mud tank through the working condition identification model and the alarm model. However, the technical solution in this patent text only considers ground data for the identification of working conditions, and the identified working conditions are limited (only the three working conditions of drilling, drilling and drilling are identified), and it is impossible to identify all working conditions that affect the leakage judgment.

[0006] In summary, current surface monitoring systems lack timely effectiveness and are immature in their ability to monitor leaks under various drilling conditions, making them unreliable. Real-time downhole leak monitoring suffers from low accuracy, and data cannot be accurately transmitted in real time. Existing monitoring methods are unable to cope with the complexities of downhole conditions under various drilling conditions. A method and system are urgently needed that can improve timeliness or real-time performance, accurately identify operating conditions, and accurately monitor leaks. Summary of the Invention

[0007] The technical solution disclosed in the present invention provides a leakage monitoring system and method based on annular space monitoring, which is used to solve at least one technical defect existing in the above-mentioned prior art.

[0008] A first aspect of the present disclosure provides a spill monitoring system based on annular space monitoring, comprising:

[0009] an annulus monitoring component for monitoring annulus monitoring information at a fixed depth in the wellbore annulus, wherein the annulus monitoring information includes annular flow velocity measurement values ​​and / or fluid composition information of the annular fluid; and

[0010] A controller is coupled with the annulus monitoring assembly and is configured to:

[0011] receiving the annulus monitoring information and logging data;

[0012] Identify drilling conditions relevant to spill monitoring;

[0013] Selecting a corresponding leakage monitoring model based on the drilling conditions;

[0014] determining a theoretical value of annular flow velocity at the specified depth based on the spill monitoring model;

[0015] determining whether the measured annular flow velocity value is within a certain range of a theoretical annular flow velocity value; and

[0016] The presence of a leak is determined in response to the annulus flow velocity measurement being outside a certain range of a theoretical annulus flow velocity.

[0017] In a further embodiment, the determined drilling condition is one of drilling, tripping, circulation, connecting a single thread, and starting and stopping a pump.

[0018] In a further embodiment, the spill monitoring model selects one of the following:

[0019] Under drilling conditions, the leakage monitoring model is at least a function of the rock volume drilled per unit time, wellbore size, drill bit depth, drill bit penetration rate, drill pipe outer diameter, and casing inner diameter;

[0020] Under tripping conditions, the spill monitoring model is at least a function of pump displacement, drill pipe speed, hook height, drill pipe outer diameter, drill pipe outer diameter, and casing inner diameter;

[0021] Under cyclic conditions, the spill monitoring model is at least a function of the pump displacement, the inner diameter of the casing, and the outer diameter of the drill pipe;

[0022] Under the single-connection condition, the leakage monitoring model is a constant value; and / or

[0023] Under the pump-on / off condition, the leakage monitoring model is at least a function of the pump displacement.

[0024] In a further embodiment, determining a drilling condition associated with leak monitoring includes receiving the drilling condition.

[0025] In a further embodiment, determining drilling conditions associated with leak monitoring includes determining the drilling conditions based on annular flow velocity measurements and mud logging data.

[0026] In a further embodiment, determining drilling conditions associated with leak monitoring includes:

[0027] Pumping on and off conditions are determined in response to rapid changes in annular flow velocity measurements over time.

[0028] In a further embodiment, determining that a leak exists in response to the annular flow velocity measurement being outside a certain range of a theoretical annular flow velocity comprises:

[0029] In response to the annular flow velocity measurement value being outside a certain range of the annular flow velocity theoretical value for a duration exceeding a predetermined value, it is determined that a leak condition exists.

[0030] In a further embodiment, the controller is further configured to:

[0031] extracting fluid composition information from the annulus monitoring information;

[0032] determining a gas holdup of the annular fluid based on the fluid composition information;

[0033] A leak condition is determined to exist in response to the air void fraction being greater than a threshold value.

[0034] In a further embodiment, determining that a leak condition exists in response to the gas holdup being greater than a threshold value includes determining that a leak condition exists in response to a duration in which the gas holdup is greater than the threshold value exceeding a set time.

[0035] In a further embodiment, the controller is further configured to:

[0036] extracting fluid composition information from the annulus monitoring information;

[0037] determining a gas holdup of the annular fluid based on the fluid composition information;

[0038] The gas holdup fraction is integrated over time; and

[0039] The presence of an overflow condition is determined in response to the integrated result being greater than a set value.

[0040] In a further embodiment, the annulus monitoring assembly includes an ultrasonic sensor, and the fixed depth is less than a depth at which the supercritical fluid is located and greater than or equal to a depth corresponding to a required spill treatment time window.

[0041] In a further embodiment, the ultrasonic sensor is disposed in the casing, cement sheath, monitoring nipple and / or casing shoe, and is communicatively coupled to the controller via an optical fiber.

[0042] In a further embodiment, the controller is further configured to:

[0043] In response to determining that a leakoff condition exists, a time for the leakoff to return to the wellhead is determined based at least on the fixed depth and a measurement of the annular flow velocity when the leakoff condition is determined to exist.

[0044] A second aspect of the present disclosure provides a leakage monitoring method based on annular space monitoring, comprising:

[0045] receiving annular space monitoring information from an annular space monitoring assembly, wherein the annular space monitoring assembly monitors annular space monitoring information at a fixed depth within the wellbore annulus, wherein the annular space monitoring information includes annular space flow velocity measurement values ​​and / or fluid composition information of the annular space fluid;

[0046] Receive logging data;

[0047] Identify drilling conditions relevant to spill monitoring;

[0048] Selecting a corresponding leakage monitoring model based on the drilling conditions;

[0049] determining a theoretical value of annular flow velocity at the specified depth based on the spill monitoring model;

[0050] determining whether the measured annular flow velocity value is within a certain range of a theoretical annular flow velocity value; and

[0051] The presence of a leak is determined in response to the annulus flow velocity measurement being outside a certain range of a theoretical annulus flow velocity.

[0052] A third aspect of the present disclosure provides a controller, comprising a memory and a processor, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the controller implements the method described in the second aspect of the present disclosure.

[0053] A fourth aspect of the present disclosure provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, enable the processor to implement the method described in the second aspect of the present disclosure.

[0054] A fifth aspect of the present disclosure provides a computer program product, comprising computer program instructions, which, when executed by a processor, enable the processor to implement the method described in the second aspect of the present disclosure.

[0055] The system, method, controller, computer-readable storage medium, and program product for leak monitoring and processing can perform real-time data monitoring at a fixed position in the wellbore, select a leak monitoring model based on the operating conditions, and implement real-time, efficient, and accurate leak monitoring of complex bottom-hole conditions under various operating conditions.

[0056] The aforementioned system, method, controller, computer-readable storage medium, and program product for leak monitoring and processing utilize an ultrasonic monitoring device at a fixed depth to measure annular flow velocity and gas content. This system establishes the relationship between leaks and annular flow velocity under various operating conditions, and also proposes a method for determining leaks that takes gas content into account. Furthermore, a method for calculating the time it takes for leaks or gas to ascend to the wellhead is established to determine the leak processing time window. This method improves the accuracy and preemptive nature of leak detection and enhances the practicality of gas intrusion monitoring at the casing shoe.

[0057] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings illustrate various examples of various aspects of the present disclosure, and together with the description, they serve to explain the principles of the present disclosure. Those skilled in the art will appreciate that the particular embodiments shown in the drawings are exemplary only and are not intended to limit the scope of the present disclosure. It should be appreciated that in some examples, one element may be designed as multiple elements, or multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may also be implemented as an external component of the other element, and vice versa. In the drawings:

[0059] FIG1 shows a spill monitoring system based on annulus monitoring according to an embodiment of the present disclosure;

[0060] 2A-2B illustrate the arrangement and communication structure of an annulus monitoring assembly in a casing or cement annulus according to an embodiment of the present disclosure;

[0061] FIG3 shows a flow chart of a method for monitoring a leak according to an embodiment of the present disclosure;

[0062] FIG4 shows a trend diagram of theoretical values ​​of annular flow velocity under pump start-stop conditions obtained under experimental conditions according to an embodiment of the present disclosure;

[0063] FIG5 shows a trend diagram of theoretical values ​​of annular flow velocity under tripping conditions obtained under experimental conditions according to an embodiment of the present disclosure; and

[0064] FIG6 shows a structural diagram of the controller 101 in FIG1 according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0065] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate relative importance or implicitly specify the number of technical features indicated. Therefore, unless otherwise specified, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features; "plurality" means two or more. The term "comprising" and any variations thereof are intended to be non-exclusive inclusion, and one or more other features, integers, steps, operations, components, elements, and / or combinations thereof may be present or added.

[0066] In addition, terms indicating orientation or positional relationships such as “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inside,” and “outside” are described based on the orientation or relative positional relationships shown in the accompanying drawings. They are merely simplified descriptions for the convenience of describing this application, and do not indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0067] Furthermore, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0068] In this application, the term "tripping" also refers to raising and lowering the drill string or drill pipe, and encompasses both "tripping" and "running" in drilling operations. The process of lifting the drill string from a hole (well) to the surface is called tripping, while the process of lowering the drill string into the hole (well) is called running. Together, the two are referred to as tripping.

[0069] In this application, the term "joining drill rods" refers to the process of extending the drill string (or drilling tool) to match the wellbore depth as the wellbore deepens. Each time the wellbore is deepened by one drill rod, a new drill rod is added to the drill string. This process is called joining drill rods.

[0070] In this application, the term "pump start and stop" refers to the pumping and stopping operations during the drilling process. Starting the pump starts the drilling pump and initiates its operation. The primary function of the drilling pump is to provide the necessary energy for the circulation of the drilling fluid, delivering the drilling fluid to the drill string at a specific pressure and flow rate, completing the entire circulation process. Stopping the pump stops the drilling pump, temporarily interrupting the circulation of the drilling fluid.

[0071] In the description of this application, the term "circulation" working condition refers to the circulation of drilling fluid driven by the drilling pump without drilling.

[0072] In the description of this application, the term "leakage" is a collective term for overflow and well leakage (or loss). Therefore, when the technical solution in this application mentions the occurrence of leakage, it refers to the occurrence of overflow or well leakage or both. Overflow refers to the phenomenon that the oil, gas and water in the formation are pressed into the wellbore due to the inability of the drilling fluid density to balance the pressure of the formation fluid, causing the drilling fluid in the wellbore to overflow. Well leakage refers to the phenomenon that the drilling fluid leaks into the formation during the drilling process. Overflow and well leakage in drilling are both caused by the imbalance between the drilling fluid and the formation pressure. Overflow is the pressure of formation fluid into the wellbore, while well leakage is the leakage of drilling fluid into the formation. Both phenomena may have a serious impact on drilling operations and even cause accidents such as blowouts and well collapses.

[0073] In the description of this application, the term "wellbore size" refers to the diameter of the hole formed during the drilling process.

[0074] The following describes in detail the specific implementations of the embodiments of the present disclosure in conjunction with the accompanying drawings. It should be understood that the specific implementations described herein are only intended to illustrate and explain the embodiments of the present disclosure and are not intended to limit the present disclosure. Moreover, for the sake of brevity, only the components closely related to the embodiments of the present application are described in detail below.

[0075] Referring to FIG. 1 , a leak monitoring system based on annular space monitoring according to an embodiment of the present disclosure is provided, primarily comprising a controller 101 and an annular space monitoring assembly 107. The annular space monitoring assembly 107 is disposed on the cement sheath 103 or casing 105 of a wellbore. Specifically, the annular space monitoring assembly 107 can be disposed within a monitoring sub that is connected to the casing 105. Alternatively, the annular space monitoring assembly can be located directly within the outer wall of the casing 105, or can be disposed on a casing shoe or within the cement sheath. The installation depth of the annular space monitoring assembly 107 (i.e., the distance from the ground or wellhead) is fixed or located at a specified location (depth) within the cement sheath 103 or casing 105. The fixed depth of the annular space monitoring assembly 107 from the ground can be set based on the requirements of the leak treatment time window (described below). The larger or longer the required leak treatment time window, the larger the fixed depth should be. For example, the fixed depth can be greater than 500 meters, 1000 meters, 2000 meters, 4000 meters, and so on. The annulus monitoring assembly 107 is used to monitor the resistivity information, flow rate information, and fluid composition information of the annulus fluid at a designated or fixed position (which may be referred to as an annulus monitoring point) in the drilling annulus 111. For example, the annulus monitoring assembly 107 may include, for example, an ultrasonic measuring device for measuring the resistivity information, flow rate information, and fluid composition information. Specifically, the ultrasonic measuring device may be a Doppler ultrasonic monitoring device. Alternatively, an electrolyte sensor, flow meter, or other collection device may be used to collect the resistivity information, flow rate information, and fluid composition information in the drilling annulus 111. In addition, the annulus monitoring assembly 107 may also include, but is not limited to, temperature sensors, pressure sensors, and / or capacitors for measuring information such as temperature, pressure, density, and viscosity changes in the drilling annulus. The annulus monitoring assembly 107 may communicate with the controller 101 via, for example, an optical fiber 102.

[0076] The controller 101 is configured to receive annular monitoring information from the annular monitoring component 107. The controller may also receive or determine logging data. The logging data may include one or more of the following: hook height, pump on / off status, standpipe pressure (or riser pressure), casing pressure (or casing pressure), drill pipe lowering speed, outer diameter of the last drill pipe lowered into the well from the wellhead, inner diameter of the last drill pipe lowered into the well from the wellhead, inner diameter of the casing at the annular monitoring point, outer diameter of the drill pipe at the annular monitoring point, wellbore size, bit pressure, drill bit depth, actual drilled depth, location or depth of the annular monitoring point (i.e., distance from the wellhead or the ground), etc.

[0077] When monitoring for leaks, the controller 101 first analyzes the fluid composition information from the annular monitoring assembly, determines the gas content of the annular fluid, and then performs leak detection based on the gas content. For example, when drilling with conventional oil-based or water-based drilling fluids, once the gas content of the annular fluid is detected to be greater than a certain threshold (e.g., 1%), indicating that the bottomhole pressure is less than the formation pressure, a leak is determined to have occurred downhole (specifically, an overflow), a leak alarm is issued, and appropriate actions are taken. In a further preferred embodiment, the duration of the gas content exceeding the certain threshold can be determined. If this duration is greater than a set time (e.g., a threshold time Δt), a leak is determined to have occurred. In yet another embodiment, the measured gas content can be integrated over time (i.e., the gas content is integrated over a selected time length (e.g., the threshold time Δt or another different time length)). If the integrated result is greater than a set value, a leak is determined to have occurred. Using the above-described duration determination method or integral determination method can avoid false leak alarms. For example, formation gas may enter the wellbore discontinuously, and using only thresholds for judgment may result in missed detections. When drilling with water-based or oil-based drilling fluids, leak detection based on gas content takes precedence. If the gas content, duration, or integration result exceeds the threshold, set time, or set value, a leak is directly determined to have occurred.

[0078] If leakage is not detected based on the gas content (e.g., the gas content is not greater than the threshold, the duration is not greater than the set time, or the integral result is not greater than the set value), the controller 101 may determine drilling operating conditions associated with leakage monitoring. For example, the well operating conditions may include at least drilling, tripping, circulation, single connection, and pump start / stop. The controller 101 may determine drilling operating conditions by receiving drilling operating conditions information from other equipment. Alternatively, the controller 101 may determine or derive drilling operating conditions based on annular monitoring information and mud logging data. For example, the controller 101 may receive flow rate information from the annular monitoring component 107 and determine pump start / stop conditions based on the rapid change in flow rate information or annular flow rate information (annular flow rate measurement) over time. The controller 101 determines tripping based on the change in hook height, well depth data, and drill bit data in the mud logging data. When the drill bit position is less than the drilled depth and the hook is being raised or lowered, the controller 101 determines that the drilling is in a tripping condition. Since connection is always performed with the pump off, the controller 101 can determine the connection operating condition based on the pump on / off status. The drilling condition is determined when the weight on bit is greater than 0 and the drill bit depth is equal to the actual drilled depth. The circulating condition is determined when the drilling pump displacement remains constant and drilling is stopped (the drill bit depth is less than the actual drilled depth, or the drill bit is a certain distance from the well bottom).

[0079] Next, the controller 101 can be configured to determine a leakage detection model (or annular flow velocity calculation model) corresponding to the determined drilling conditions based on the determined drilling conditions. The leakage detection model is used to calculate the theoretical annular flow velocity under the determined drilling conditions. The controller 101 then determines whether a leakage exists based on the relationship between the annular flow velocity measured by the annular monitoring assembly 107 and the theoretical annular flow velocity. For example, if the measured annular flow velocity is equal to the theoretical annular flow velocity or is within a certain range of the annular flow velocity, a leakage is determined to be absent; otherwise, a leakage is determined to be present.

[0080] In the above-mentioned embodiment of the present disclosure, the annulus monitoring component 107 is located at a specified position of the cement sheath 103 or casing 105 of the drilling well, or the annulus monitoring component 107 is located at a specified position of the drilling annulus, and the distance from the ground or the wellhead is fixed. Therefore, the position of the drilling annulus is stable, the measurement object is stable, and it is less affected by downhole noise and extreme environments, and accurate measurement results can be obtained. Preferably, the height of the annulus monitoring component 107 in the drilling annulus, casing, and cement sheath is higher than the height of the supercritical fluid, or in other words, the depth of the annulus monitoring component 107 in the drilling well is less than the depth of the supercritical fluid. Since the distance of the annulus monitoring component 107 from the ground is fixed, a wired method (such as optical fiber) 102 can be used for data transmission, and a large amount of measured data can be transmitted to the controller 101 in real time and reliably. Real-time monitoring within the drilling annulus by the annular monitoring assembly 107 reduces the delay in surface leak detection, overcoming the lack of timeliness of surface leak detection, extending the time for leak resolution, and reducing well control risks. Furthermore, it takes into account the human factors under various drilling conditions, eliminating false leaks caused by human error or changes in operating conditions.

[0081] 2A-2B , which illustrate the arrangement and communication structure of an annulus monitoring assembly in a casing or cement sheath according to an embodiment of the present disclosure. First, refer to FIG2A , which illustrates the arrangement of an annulus monitoring assembly 207 (also referred to as an annulus monitoring device). As shown, the annulus monitoring assembly 207 can be arranged in a measuring nipple, which is connected to the casing. Alternatively, the annulus monitoring assembly 207 can be arranged directly in the casing 201, and further alternatively, the annulus monitoring device can be arranged in a cement sheath or casing shoe. For ease of description, casing 201 is used below to represent a measuring nipple, casing, cement sheath, or casing shoe. One or more annulus monitoring assemblies 207 (e.g., a Doppler ultrasonic monitoring device) are disposed in the casing 201. For example, FIG2A shows three annulus monitoring assemblies 207, which are evenly arranged along the circumference of the casing 207 to make the test results more accurate and comprehensive. Then refer to FIG2B , which illustrates the arrangement of the communication channel. The communication cable (preferably an optical fiber) 203 can be embedded in the casing 201. In this embodiment, the external shape of the communication cable 203 can be a flat oval, and a semi-open groove of matching size can be cut out of the surface of the casing 201, so that the communication cable 201 can be embedded in the outer wall of the casing 201, or can be inserted into the groove of the casing 201 by a mechanical zipper. Alternatively, the communication cable 203 can also be fixed to the surface of the casing 11, fixed to the stabilizer, or semi-embedded in the casing 11 so that it can be lowered into the drilling annulus with the casing when the casing 11 is lowered. In this embodiment, the communication cable 201 is preferably fixed and installed by pre-buried in the cement ring underground or embedded in the outer wall of the casing underground. In other embodiments, the external shape of the communication cable 201 can also be designed into various suitable shapes such as rectangle and circle according to the thickness and strength of the casing wall.

[0082] Next, refer to Figure 3, which shows a flow chart of a method for monitoring a leak according to an embodiment of the present disclosure. The method can be executed by the controller 101 shown in Figure 1. As shown, the method begins at step 300. Next, at step 302, the controller receives annular monitoring information from an annular monitoring assembly located at a fixed depth in the wellbore. As previously mentioned, the annular monitoring assembly can be fixed at a fixed distance from the wellhead or the surface, thereby monitoring the drilling fluid at the fixed depth in the wellbore to obtain annular monitoring information. The annular monitoring information includes at least resistivity information, flow rate information, and / or fluid composition information of the annular fluid. Based on the annular monitoring information (specifically, based on the fluid composition information), the controller can derive the gas content of the annular fluid. Next, the method proceeds to step 304. At step 304, the controller compares the determined gas content of the drilling fluid with a gas content threshold (e.g., 1%). If the gas content of the annular fluid is detected to be greater than the gas content threshold, indicating that the bottomhole pressure is less than the formation pressure, a leak (specifically, an overflow) is determined to have occurred downhole. In a further preferred embodiment, the duration of the gas content being greater than a certain threshold can be determined. If the duration is greater than a set time (e.g., a threshold time Δt), leakage is determined to have occurred. In yet another embodiment, the measured gas content can be integrated based on time. If the integration result is greater than a set value, leakage can be determined to have occurred. The use of the above-mentioned duration judgment method or integration judgment method can avoid false alarms of leakage. For example, formation gas may enter the wellbore discontinuously. If only the threshold is used for judgment, missed alarms may occur. When drilling with water-based drilling fluid or oil-based drilling fluid, leakage judgment based on gas content has priority. If the above-mentioned gas content, duration, or integration result is greater than the above-mentioned threshold, set time, or set value, it is directly determined that leakage has occurred.

[0083] In response to the detected gas holdup being greater than the gas holdup threshold, the method proceeds to step 314. At step 314, the time from detection of the leak to the leak returning to the wellhead is calculated. This time is called the leak handling time window and is used to provide time guidance for handling the leak.

[0084] In response to the detected gas content being no greater than (e.g., less than or equal to) the gas content threshold, the method proceeds to step 306. At step 306, the controller determines which drilling condition is currently in effect. The drilling conditions include, for example, at least: drilling, tripping, circulation, single connection, and pump start / stop. The controller can determine the drilling condition by receiving drilling condition information from other equipment. Alternatively, the controller can derive or derive drilling condition information based on annular monitoring information and logging data. For example, the controller can receive flow rate information from the annular monitoring assembly and determine the pump start / stop condition based on the rapid change in flow rate information over time. The controller determines tripping based on the change in hook height, well depth data, and drill bit data in the logging data. When the drill bit position is less than the drilled depth and the hook is being raised and lowered, the controller determines that the drilling condition is tripping. Since single connection is always performed in the pump-off state, the controller 101 can determine the single connection condition based on the pump switch state. The drilling condition is determined when the bit pressure (Pb, in MPa) is greater than 0 and the drill bit depth (Hb, in m) is equal to the actual drilled depth (Hr, in m). The circulating condition is determined when the drilling pump displacement remains unchanged and drilling is stopped (the drill bit depth is less than the actual drilled depth, or the drill bit is a certain distance from the bottom of the well).

[0085] Next, the method proceeds to step 308, where the controller may be configured to determine, based on the determined drilling conditions, a leakage determination model corresponding to the conditions. The leakage determination model is also referred to as an annular flow velocity calculation model. The leakage determination model calculates the theoretical annular flow velocity under the determined drilling conditions. The inventors of the present disclosure have discovered that under different drilling conditions, the annular flow velocity is correlated with different parameters, and accordingly, the leakage determination model is correlated with different parameters.

[0086] If the current drilling condition is determined to be a tripping condition, the spill judgment model or annular velocity calculation model for the tripping condition is selected. The annular velocity calculation model for the tripping condition is as follows:

[0087] Where: Va, annular velocity, unit: m / s;

[0088] Q, pump displacement, unit L / s.

[0089] V p , drill pipe lowering speed, unit: m / s;

[0090] h, hook height, unit: m;

[0091] t, time, unit s;

[0092] D pO , the outer diameter of the last drill pipe lowered into the wellhead, in meters;

[0093] DpI , the inner diameter of the last drill pipe lowered into the wellhead, in meters;

[0094] D McI , the inner diameter of the casing where the annulus monitoring component is located, in m;

[0095] D MpO The outer diameter of the drill pipe where the annulus monitoring component is located, in meters.

[0096] If the current drilling condition is determined to be a circulation condition, the leakage judgment model or annular velocity calculation model for the circulation condition is selected. The annular velocity calculation model for the circulation condition is as follows:

[0097] If the current drilling condition is determined to be normal, the leakage judgment model or annular flow velocity calculation model for normal drilling conditions is selected. The annular flow velocity calculation model for normal drilling conditions is as follows:

[0098] Where: Volume of rock drilled per unit time, unit m 3 / s;

[0099] Dh, wellbore size, in m;

[0100] Hb, drill bit depth, unit: m;

[0101] Drilling speed

[0102] If the current drilling operation is determined to be connecting or disconnecting a single well, since this operation is generally performed with the pump stopped, the leakage judgment model expression for connecting or disconnecting a single well is Va=0.

[0103] For the pump-on / off working condition, due to different drilling conditions, the flow rate change trend of the pump-on / off condition can be collected experimentally, and the functional relationship between the annular flow velocity and the pump displacement under the pump-on / off condition can be obtained by fitting, that is, the annular flow velocity calculation model: V a =f(Q) (6)

[0104] Where: Va, annular velocity, unit: m / s;

[0105] Q, pump displacement, unit L / s.

[0106] For example, see Figure 4, which shows a trend graph (or curve chart) of the theoretical annular velocity under experimental conditions for pump-on / off operation. The horizontal axis represents time (s) and the vertical axis represents the theoretical annular velocity (m / s). This trend graph can be used to establish a spill detection model or annular velocity calculation model for pump-on / off operation.

[0107] In addition, alternatively, for other working conditions, in addition to the formula of the above annulus flow rate calculation model, a trend graph (or curve graph) of the theoretical value of the annulus flow rate under the corresponding working conditions obtained under experimental conditions can also be used, and then a spill judgment model or an annulus flow rate calculation model can be established. For example, referring to FIG. 5, it shows a trend graph (or curve graph) of the theoretical value of the annulus flow rate under the tripping operation conditions obtained under experimental conditions, and through this trend graph, a spill judgment model or an annulus flow rate calculation model for the tripping operation conditions can be established.

[0108] After selecting the corresponding annulus flow rate calculation model based on the drilling working conditions, the method proceeds to step 310, and the theoretical value Va of the annulus flow rate is calculated based on the selected annulus flow rate calculation model.

[0109] Next, the method proceeds to step 312, and the controller determines the relationship between the measured value Vt of the annulus flow rate obtained from the annulus monitoring component and the theoretical value Va of the annulus flow rate. Specifically, the controller determines whether the measured value V of the annulus flow rate t is within the tolerance range of the theoretical value Va of the annulus flow rate, that is, it is judged whether a [[ID=***11]]V - θ < V t < V a < V + θ holds. In the formula: θ represents the tolerance, generally 1% - 5% of Va, and can also be taken according to the actual situation, and the unit of θ is m / s. If V t is within the tolerance range of the theoretical value Va of the annulus flow rate, it is judged that no spill situation has occurred, and the method can return to step 302 to continue monitoring. If V t is outside the tolerance range of the theoretical value Va of the annulus flow rate, it is judged that a spill situation has occurred. Specifically, when V t > Va + θ, it is directly judged that a blowout has occurred, and when V[[ID=***22]] t < Va - θ, it is judged that there is a downhole loss. Preferably, in order to eliminate false alarms or misalarms, a threshold time Δt can be set. If V t is outside the tolerance range of the theoretical value Va of the annulus flow rate for a duration exceeding Δt, it is determined that there is a spill situation. A spill alarm can be given or a spill mitigation measure can be reminded to be taken. Next, optionally, the method can proceed to step 314.

[0110] At 314, if it is judged that a blowout has occurred, that is, V t > Va + θ, the time from when the blowout is monitored to when the blowout returns to the wellhead is calculated, and the reaction time of the surface personnel is reasonably calculated, so as to discover and handle it in time and ensure the safety of drilling. The calculation formula is as follows: [[ID=***32]] [[ID=***33]]

[0111] Hs, the depth of the annulus monitoring component position, that is, the distance from the wellhead or the ground, m; It should be noted that there seem to be some formatting or numbering issues in the original text (e.g., the repeated and incomplete lines in the middle). The translation is done based on the best understanding of the text. If you have any further clarifications, please feel free to let me know.

[0112] Vt, the measured value of the annular velocity when a spill is determined, m / s.

[0113] Preferably, if the above threshold time Δt is used for judgment, the time to return to the wellhead is calculated as follows:

[0114] Where: Hs, the depth of the annulus monitoring component, i.e. the distance from the wellhead or the ground, m;

[0115] Vtt is the annular flow velocity measured at the moment of overflow after monitoring for Δt time, m / s;

[0116] T, time from overflow to wellhead, s;

[0117] t0, the initial moment when the annular velocity is detected to be outside the tolerance range of the theoretical value, s;

[0118] tt, the time when overflow occurs determined after monitoring for Δt time, s.

[0119] Further preferably, as the pressure on the gas gradually decreases during its ascent in the wellbore, the gas volume gradually expands. When considering the gas expansion, by calculating the gas migration velocity (or the speed of movement toward the wellhead), and taking into account the gas expansion due to the decrease in pressure during the ascent, a reasonable estimate of the time it takes for the gas to migrate to the wellhead can be made. V t =V t0 +at (9)

[0120] Substituting equations (9) and (10) into equation (8), we can obtain:

[0121] Where: a, gas migration acceleration, m / s -2 ;

[0122] m, monitored gas mass, kg;

[0123] ρ, annular fluid density, g / cm -3 ;

[0124] V, monitored gas volume, m 3 .

[0125] The finite element method is used to calculate the above equation (11), and the maximum time window T (leakage treatment time window) from gas monitoring to gas migration to the wellhead is finally calculated, which can promptly remind ground personnel to carry out overflow treatment and ensure safe and efficient operations.

[0126] The following table shows the calculated spill handling time windows when the annulus monitoring assembly is located at different monitoring depths.

[0127] As can be seen from the above table, by adopting the spill monitoring solution of the embodiment of the present application, spills can be effectively detected in advance, providing ground personnel with sufficient time to deal with the spill.

[0128] Alternatively, the minimum time required to handle a spill, i.e., the required spill handling time window, can be determined based on prior knowledge (e.g., experience) or other algorithms. After determining the required spill handling time window, the monitoring depth, or depth from the ground, of the annulus monitoring assembly can be selected based on the time window.

[0129] The method for monitoring a leak is described above with reference to FIG3 . However, those skilled in the art will appreciate that the above steps do not necessarily need to be performed sequentially and may be performed simultaneously or in an alternate order. Alternatively, within the scope of the present application, some steps in the above method may be combined into one step, one step may be split into multiple steps, or some steps may be removed, as long as the method still solves the technical problem to be solved by the present application.

[0130] Next, refer to Figure 6, which shows a block diagram of the controller 101 in Figure 1. Referring to Figure 6, the controller 101 includes a processor 601, a memory 602, and an interface 603. The processor 601 implements the operation of the controller 101 by executing computer-executable instructions that define the method shown in Figure 3. A computer program product including the computer-executable instructions can be stored in the memory 602. The method described in Figure 3 can be defined by the computer-executable instructions included in the computer program product stored in the memory 602 and controlled by the processor 601 executing the computer-executable instructions. The interface 603 can include a network interface for communicating with other devices via a network, and can also include other input / output devices (e.g., a display, keyboard, mouse, speaker, buttons, touchpad, touch screen, etc.) that enable a user to interact with the controller 210. Those skilled in the art will recognize that actual control system implementations may also include other components, and Figure 6 is a high-level representation of some components of such a control system for illustrative purposes.

[0131] Memory 602 includes tangible, non-transitory machine-readable storage media and may also include high-speed random access memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), double data rate synchronous dynamic random access memory (DDRRAM), or other random access solid-state memory devices, and may include non-volatile memory, such as one or more magnetic disk storage devices (such as internal hard disks and removable disks), magneto-optical disk storage devices, optical disk storage devices, flash memory devices, semiconductor memory devices (such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), compact disk read-only memory (CD-ROM), digital versatile disk read-only memory (DVD-ROM) disks, or other non-volatile solid-state storage devices.

[0132] In the embodiments of the present disclosure, real-time data monitoring can be performed at a designated or fixed position in the wellbore underground, and logging data, surface monitoring information and annular space monitoring information can be obtained at the same time. The current drilling conditions can be identified based on the data obtained, and leakage monitoring can be performed for each condition with a leakage monitoring model; thus, real-time, efficient and accurate leakage monitoring of complex bottom hole conditions under various conditions can be achieved.

[0133] While embodiments of the present disclosure have been described in detail above, it should be appreciated that certain features of the present disclosure described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure described in the context of a single embodiment for simplicity may also be provided individually or in any suitable subcombination or in any other described embodiment of the present disclosure as appropriate. Certain features described in the context of various embodiments should not be considered essential features of those embodiments unless the embodiment would be ineffective without those elements.

[0134] Although the present disclosure has been described in conjunction with the specific embodiments thereof, it is apparent that many substitutions, modifications and variations will be apparent to those skilled in the art. It is therefore intended to encompass all such substitutions, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0135] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and specifically indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this disclosure should not be construed as an admission that such reference is available as prior art to the present disclosure. Where section headings are used, they should not be construed as necessarily limiting.

Claims

1. An annular space monitoring system for detection of production and absorption, comprising: an annulus monitoring unit configured to receive annulus monitoring information at a fixed depth within the drilled annulus from the earth's surface, wherein the annulus monitoring information includes measured values ​​of fluid flow rate in the annulus and / or information about fluid components; and a controller connected to the annulus monitoring unit, wherein the controller is configured to: receive annular space monitoring information and gas logging data; determine the operating status related to monitoring of manifestation and absorption; select the appropriate manifestation and absorption monitoring model based on the operating status; calculate the theoretical value of the flow velocity in the annulus at a fixed depth in accordance with the manifestation and absorption monitoring model; determine whether the measured annulus flow velocity value falls within a specified range of the theoretical annulus flow velocity value; and determine whether a development or absorption is occurring in response to the measured annular flow velocity value being outside a specified range of the theoretical annular flow velocity value.

2. An annular space monitoring system for detecting production and absorption according to claim 1, wherein the determined operating state is one of the following states: drilling, tripping, circulation, build-up, pump start-up and pump stop.

3. The annular space monitoring system for detecting occurrence and absorption according to claim 2, wherein the occurrence and absorption monitoring model is selected as one of the following: in the drilling state, the absorption and production monitoring model is at least a function of the volume of drilled rock per unit time, the borehole size, the bottom hole depth, the drilling speed, the outside diameter of the drill pipe, and the inside diameter of the casing; in the tripping operation state, the manifestation and absorption monitoring model is at least a function of the pump flow rate, the drill pipe running / lifting speed, the traveling block height, the drill pipe outside diameter, and the casing inside diameter; under the circulation condition, the pattern of monitoring the manifestation and absorption is at least a function of the pump volumetric flow rate, the inside diameter of the casing and the outside diameter of the drill pipe; in the build-up state, the pattern of monitoring the manifestation and absorption is a constant value; and / or under the pump start and stop conditions, the manifestation and absorption monitoring model is at least a function of the pump volumetric flow.

4. The annular space monitoring system for detecting shows and absorptions according to claim 2, in which determining the operating state associated with monitoring the shows and absorptions comprises obtaining the operating state.

5. The annular space monitoring system for detecting shows and losses according to claim 2, in which determining the operating state associated with monitoring shows and losses comprises determining the operating state based on a measured value of the annular space flow velocity and / or mud logging data.

6. The annular space monitoring system for detecting shows and losses according to claim 5, in which the determination of the operating state associated with monitoring shows and losses comprises the following: determine the operating state of the pump start and stop in response to a rapid change over time of the measured value of the flow velocity in the annulus.

7. The annulus monitoring system for detecting kicks and losses according to claim 1, wherein determining that a kick or loss is occurring in response to the measured value of the annulus flow velocity being outside a specified range of the theoretical value of the annulus flow velocity comprises the following: determine that manifestation occurs or absorption occurs if the duration of the measured value of the annular flow velocity being outside a certain range of the theoretical value of the annular flow velocity exceeds a specified value.

8. An annular space monitoring system for detecting manifestations and absorptions according to claim 1, in which the controller is also configured to: extract fluid component information from annulus monitoring information; calculate the gas content of fluids in the annulus based on information about the fluid components; and determine whether development or absorption is occurring in response to the gas content exceeding a threshold value.

9. The annulus monitoring system for detecting kicks and losses according to claim 8, wherein determining that kicks or losses occur in response to the gas content exceeding a threshold value comprises the following: determining that kicks or losses occur if the gas content above the threshold value persists for longer than a specified period of time.

10. An annular space monitoring system for detecting manifestations and absorptions according to claim 1, in which the controller is also configured to: extract fluid component information from annulus monitoring information; calculate the gas content of fluids in the annular space based on information about the fluid components; perform integration of gas content over time; and determine whether development or absorption occurs in response to the integration result exceeding a specified value.

11. An annular space monitoring system for detecting shows and absorptions according to any one of claims 1-10, in which the annular space monitoring unit comprises an ultrasonic sensor, and the fixed depth is less than the depth at which supercritical fluids exist and greater than or equal to the depth corresponding to the time window required to stop the show or absorption.

12. The annular space monitoring system for detecting shows and absorptions according to claim 11, in which the ultrasonic sensor is located in the casing, cement lining, monitoring sub and / or casing shoe and is connected to the controller with the ability to communicate via optical fibers.

13. An annular space monitoring system for detecting manifestations and absorptions according to any of paragraphs 1-10, in which the controller is also configured to: in response to the detection of a show or loss, calculate the time required for the show / loss fluid to return to the wellhead, at least in accordance with the fixed depth and the measured value of the annular flow velocity obtained when the show or loss was confirmed.

14. A method for monitoring the annular space to detect manifestations and absorptions, characterized in that receiving annulus monitoring information from an annulus monitoring unit, wherein the annulus monitoring unit receives annulus monitoring information at a fixed depth within the drilling annulus, and the annulus monitoring information includes measured values ​​of fluid flow rate in the annulus and / or information about fluid components; accept gas logging data; determine the operating status associated with monitoring manifestations and absorptions; select the appropriate manifestation and absorption monitoring model based on the operating status; calculate the theoretical value of the flow velocity in the annulus at a fixed depth in accordance with the manifestation and absorption monitoring model; determining whether the measured value of the annular flow velocity falls within a specified range of the theoretical value of the annular flow velocity; and and determine that development or absorption occurs in response to the measured annular flow velocity value being outside a specified range of the theoretical annular flow velocity value.

15. The method of claim 14, wherein the determined operating state is one of the following states: drilling, tripping, circulation, build-up, pump start-up and pump stop.

16. The method according to claim 14, wherein the monitoring model for manifestation and absorption is selected as one of the following: in the drilling state, the absorption and production monitoring model is at least a function of the volume of drilled rock per unit time, the borehole size, the bottom hole depth, the drilling speed, the outside diameter of the drill pipe, and the inside diameter of the casing; in the tripping operation state, the manifestation and absorption monitoring model is at least a function of the pump flow rate, the drill pipe running / lifting speed, the traveling block height, the drill pipe outside diameter, and the casing inside diameter; under the circulation condition, the pattern of monitoring the manifestation and absorption is at least a function of the pump volumetric flow rate, the inside diameter of the casing and the outside diameter of the drill pipe; in the build-up state, the pattern of monitoring the manifestation and absorption is a constant value; and / or under the pump start and stop conditions, the manifestation and absorption monitoring model is at least a function of the pump volumetric flow.

17. The method of claim 14, wherein determining the operating state associated with monitoring manifestations and absorptions comprises obtaining the operating state.

18. The method of claim 15, wherein determining the operating state associated with monitoring the manifestations and absorptions comprises determining the operating state based on a measured value of the flow velocity in the annulus and mud logging data.

19. The method according to claim 17, wherein determining the operating state associated with monitoring manifestations and absorptions comprises the following: determine the operating state of the pump start and stop in response to a rapid change over time of the measured value of the flow velocity in the annulus.

20. The method of claim 14, wherein determining that a development or absorption is occurring in response to the measured annulus flow velocity value being outside a specified range of a theoretical annulus flow velocity value comprises the following: determine that manifestation or absorption occurs when the duration of the measured value of the annular flow velocity outside a certain range of the theoretical value of the annular flow velocity exceeds a specified value.

21. The method according to paragraph 14, in which additionally: extract information about fluid components from annulus monitoring information; calculate the gas content of fluids in the annulus based on information about the components of the fluid; and determine that development or absorption occurs in response to the gas content exceeding a threshold value.

22. The method of claim 21, wherein determining that development or absorption occurs in response to the gas content exceeding a threshold value comprises the following: determining that development or absorption occurs if the duration of the period during which the gas content is above the threshold value is greater than a specified period of time.

23. The method according to claim 14, further comprising the following: extract information about fluid components from annulus monitoring information; calculate the gas content of fluids in the annular space based on information about the fluid components; perform integration of the gas content over time; and determine that development or absorption occurs in response to the integration result exceeding a specified value.

24. The method according to any one of paragraphs 14-23, in which the annulus monitoring unit comprises an ultrasonic sensor, and the fixed depth is less than the depth at which supercritical fluids exist, and greater than or equal to the depth corresponding to the time window necessary to stop the manifestation or absorption.

25. The method according to any one of paragraphs 14-23, which also in response to the detection of a show or absorption, the time required for the show / absorption fluid to return to the wellhead is calculated, at least in accordance with the fixed depth and the measured value of the flow velocity in the annulus obtained when the show or absorption is confirmed.

26. A controller comprising a memory and a processor, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the controller is capable of performing the method according to any one of paragraphs 14-25.

27. A machine-readable storage medium storing computer program instructions, wherein when the computer program instructions are executed by a processor, the processor is capable of implementing the method according to any of paragraphs 14-25.

28. A computer program product containing computer program instructions, wherein execution of the computer program instructions by a processor enables the processor to implement the method according to any of paragraphs 14-25.