Marine drilling shallow gas monitoring and shunting device and method

Abstract

The invention provides a marine drilling shallow gas monitoring and shunting device and method. The marine drilling shallow gas monitoring and shunting device comprises a wellhead sealing and shunting device, a formation fluid monitoring and shunting device and a remote control device. The method comprises the steps of determining the direction of a blowout prevention pipeline, selecting the size of a blowout pipeline suitable for construction, establishing a calculation model and conducting risk assessment, conducting software comprehensive analysis to achieve early warning on early discovery of shallow gas, designing a pipeline anti-blocking purging device, and remotely controlling the blowout direction of the blowout pipeline. Through the novel wellhead sealing and shunting device, the micro-flow shallow gas monitoring device, the remote rapid shunting blowout device and the pipeline anti-blocking device, and a remote monitoring and control module, rapid judgment and early warning of early discovery of shallow gas are realized in a real-time sealed wellhead environment, and related valve states are rapidly acted, so that the safety of a well is ensured. And the well control risk is reduced, and the harm of shallow gas to a drilling platform and operators can be fundamentally solved.

Description

Technical Field

[0001] The present invention belongs to the field of oil and gas drilling engineering, and particularly relates to a monitoring and diversion device and method for shallow gas in offshore drilling, which is applicable to the drilling operations of different types of offshore drilling platforms. Background Technique

[0002] With the rapid development of offshore oil and gas exploration and development technologies, the scale of offshore oil and gas development has gradually increased. Shallow gas is one of the common geological disasters encountered in offshore drilling, and usually has the characteristics of being difficult to predict, having a relatively high formation pressure, shallow burial depth, and great harmfulness. During the drilling process, once shallow gas is encountered, the gas can often reach the wellhead through the riser within a short period of time. If it cannot be detected in time or the operation is improper, it is very easy to trigger a well kick or even a blowout accident, thus causing catastrophic damage to equipment and personnel.

[0003] According to the current statistics of offshore shallow gas blowout data, the factors leading to shallow gas blowouts mainly include five aspects: operation errors, equipment failures, unreasonable designs, management factors, and environmental risk factors. Among them, equipment failures (including diverter equipment failures and wellhead seal device failures) and operation errors account for up to 95%.

[0004] Currently, the most common method for preventing shallow gas in offshore drilling is to connect the riser to the diverter by welding a connection flange matching the diverter at the upper end of the riser, install an annular blowout preventer at the top of the diverter, and then install a conduit at the top of the annular blowout preventer for discharging drilling fluid to the sea. The specific installation structure is as Figure 1 shown. Its working principle is that after the platform comprehensive mud logging detects an increase in the gas hydrocarbon value, it reports to the project supervisor. The project supervisor gives an order to open the blowout gates at both ends of the diverter and simultaneously close the upper annular blowout preventer for blowout operations.

[0005] Although the existing well control equipment can basically meet the prevention of shallow gas, there are also the following deficiencies: 1. Lack of effective monitoring for the early detection of shallow gas. The existing equipment can only judge shallow gas by monitoring the gas measurement value through the platform comprehensive mud logging. By then, the shallow gas at the bottom of the well has already risen to the wellhead, resulting in an increased well control risk; 2. Difficulty in wellhead control. Due to the high pressure and shallow burial depth of shallow gas, the time from discovery to out-of-control is short, and conventional equipment cannot seal the wellhead in real time. Once the well shut-in and diversion blowout fails, the gas directly impacts the drilling platform from the wellbore, which will cause catastrophic consequences; 3. After using the annular blowout preventer to shut in the well, it is impossible to rotate and run or pull out drill pipes, thus increasing the risk of accidents such as the drill pipe getting stuck or buried underground, and it will also bring inconvenience to the later kill operation.

[0006] Therefore, it is urgent to develop prevention and early warning technologies and equipment for shallow offshore drilling. The intelligence and safety of shallow gas prevention in the ocean will become an inevitable trend and development direction in the future. Summary of the Invention

[0007] To solve the above problems, the present disclosure provides an offshore drilling shallow gas monitoring and diversion device and method, which can seal the wellhead in real time during the drilling process, comprehensively monitor the early detection of shallow gas, and can quickly divert the shallow gas remotely once it is detected, thoroughly solving the impact and harm caused by shallow gas to the platform.

[0008] For this purpose, the present invention proposes an offshore drilling shallow gas monitoring and diversion device, including a wellhead sealing and diversion device, a formation fluid monitoring and diversion device, and a remote control device;

[0009] The wellhead sealing and diversion device includes a drill pipe sealing assembly, a wellhead sealing housing, a reducing flange, and a wellhead diversion tee; the drill pipe sealing assembly penetrates through the wellhead sealing housing from top to bottom and maintains a seal, the lower end of the wellhead sealing housing is connected to the wellhead diversion tee through the reducing flange, and the bottom of the wellhead diversion tee is connected to the riser casing head;

[0010] The formation fluid monitoring and diversion device includes a main pipeline, a blowout prevention pipeline, a wellhead pressure monitoring sensor, a remote video monitor, a gas detector, a gas source pipeline, an electromagnetic flowmeter, and a number of hydraulic plug valves; one end of the main pipeline is connected to the third end of the wellhead diversion tee, the wellhead pressure monitoring sensor is connected in series on the main pipeline, and the electromagnetic flowmeter is connected in parallel on the main pipeline; the gas source pipeline is communicated with the main pipeline, and a ball valve is installed on the gas source pipeline; the blowout prevention pipeline is communicated with the main pipeline, and the gas detector is connected to the blowout prevention pipeline;

[0011] The remote control device includes a hydraulic plug valve control device, a remote video monitoring system, and a micro-flow shallow gas monitoring and warning system; a number of the hydraulic plug valves are respectively connected to the hydraulic plug valve control device through hydraulic pipelines, the remote video monitoring system is connected to the remote video monitor through a signal transmission line; the micro-flow shallow gas monitoring and warning system collects the data of the wellhead pressure monitoring sensor, the gas detector, and the electromagnetic flowmeter through a signal transmission line.

[0012] Further, the drill pipe sealing assembly has an upper drill pipe and a lower drill pipe, and the upper drill pipe and the lower drill pipe are connected by a rotating bearing in the middle; the upper drill pipe is surrounded and sealed by an upper drill pipe sealing rubber core, and the lower drill pipe is surrounded and sealed by a lower drill pipe sealing rubber core.

[0013] Further, a cooling and lubricating inlet is provided on the side wall of the upper chamber of the drill pipe seal formed by the drill pipe sealing assembly and the wellhead sealing housing, and the cooling and lubricating inlet is connected to the bearing cooling and lubricating device in the remote control device through a cooling and lubricating hydraulic pipeline.

[0014] Furthermore, the wellhead sealing housing includes a housing body, a hydraulic clamp, and a grouting pipeline interface; wherein, a hydraulic cylinder body on the hydraulic clamp is connected to a clamp hydraulic control device in the remote control device through a hydraulic pipeline.

[0015] Furthermore, the wellhead sealing housing further includes a hydraulic cylinder manual locking device that matches the hydraulic clamp.

[0016] Furthermore, a hydraulic rotary plug valve is respectively arranged at both ends of the electromagnetic flowmeter; a hydraulic rotary plug valve is provided at a position corresponding to the electromagnetic flowmeter on the main pipeline.

[0017] Furthermore, the formation fluid monitoring and diversion device further includes a drilling pump stroke sensor, and the drilling pump stroke sensor is connected to the micro-flow shallow gas monitoring and early warning system through a signal transmission line.

[0018] Furthermore, a wind vane is fixed on the outside of the blowout prevention pipeline.

[0019] Furthermore, the micro-flow shallow gas monitoring and early warning system includes a micro-flow real-time monitoring module, an overflow and loss cumulative total or segmented intelligent statistical and mathematical calculation model module, a combustible and toxic and harmful gas real-time monitoring module, and a shallow gas intelligent comprehensive judgment and early warning module.

[0020] The present invention also proposes a method for monitoring and diverting shallow gas in offshore drilling, which is realized by using the offshore drilling shallow gas monitoring and diversion device, and includes the following steps:

[0021] S1: Determine the orientation of the blowout prevention pipeline according to the sea area position where the drilling platform is located, the construction season, and the variation law of the surface sea current and monsoon.

[0022] S2: According to the magnitude of the formation leakage pressure P_leak of the adjacent well, perform simulation fitting calculations on different displacement, wellbore size, drill string assembly, and bottom hole pressure during the drilling process, and select the size of the blowout prevention pipeline suitable for the construction requirements.

[0023] S3: Establish a circulating pressure loss calculation model, a bottom hole pressure calculation model, a leakage pressure calculation model, a wellbore stability calculation model, a fluctuation pressure calculation model, an overflow volume calculation model, and a leakage volume calculation model to conduct a risk assessment on the hazards of shallow gas.

[0024] S4: Through devices such as sensors, real-time collect drilling pump stroke data, outlet real-time flow rate values, wellhead pressure values, and drilling fluid outlet gas logging monitoring data, perform model fitting calculations, compare the inlet and outlet flow rates in real time, and conduct comprehensive analysis through software to realize early detection and early warning of shallow gas.

[0025] S5: Design a pipeline anti-blocking purging device based on the characteristics of loose geological structure on the ocean surface during drilling, large drilled hole diameter, high drilling displacement, and a large amount of sediment carried in the drilling fluid.

[0026] S6: According to the change of the real-time wind direction, remotely control the direction of blowout of the blowout pipeline in real time.

[0027] Compared with the prior art, the present disclosure has the following advantages:

[0028] In view of the characteristics of shallow gas that may be encountered during ocean drilling, such as being difficult to predict, having a relatively high formation pressure, shallow burial depth, and great harmfulness, combined with the backward technology of existing shallow gas prevention equipment, inconvenient operation, inability to monitor the discovery of early shallow gas, and great potential safety hazards, a new technical solution for shallow gas monitoring and diversion in ocean drilling is proposed. Based on the original technical solution for shallow gas prevention, by inventing a new type of wellhead sealing and diversion device, micro-flow shallow gas monitoring device, remote rapid diversion and blowout device, and pipeline anti-blocking device, a remote monitoring and control module is invented, realizing rapid judgment and early warning of the discovery of early shallow gas in a real-time sealed environment at the wellhead, and quickly acting on the states of relevant valves, greatly reducing the well control risk, fundamentally solving the harm brought by shallow gas to the drilling platform and operating personnel, achieving early detection and early prevention, providing valuable basis for the formulation of the technical solution of the project team, and winning valuable time for platform emergency and well killing operations. This method can be widely applied to the field of ocean drilling.

[0029] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic installation diagram of a common wellhead for existing shallow gas prevention;

[0032] Figure 2 It is a schematic structural diagram of the shallow gas monitoring and diversion device for ocean drilling of the present invention;

[0033] Figure 3 It is a structural block diagram of the remote control device in the device of the present invention;

[0034] Figure 4 This is a flow chart of the method for monitoring and diverting shallow gas in offshore drilling of the present invention;

[0035] Explanation of reference numerals in the drawings

[0036] 100, Wellhead sealing and diverting device; 200, Formation fluid monitoring and diverting device; 300, Remote control device; 101, Cooling and lubrication access port; 102, Upper drill pipe sealing rubber core; 103, Hydraulic clamp; 104, Lower drill pipe sealing rubber core; 105, Reducing flange; 106, Wellhead diverting tee;

[0037] 201, Wellhead pressure monitoring sensor; 202 / 202″, Remote video monitor; 203 / 203″, Gas detector; 204 / 204″, Wind vane; 205, Ball valve; 206, Gas supply pipeline; 207, Drilling pump stroke sensor; 208, Electromagnetic flowmeter; A, Hydraulic plug valve; B, Hydraulic plug valve; C, Hydraulic plug valve; D, Hydraulic plug valve; E, Hydraulic plug valve; F, Hydraulic plug valve;

[0038] 301, Bearing cooling and lubrication device; 302, Clamp hydraulic control device; 303, Hydraulic plug valve control device; 304, Remote video monitoring system; 305, Micro - flow shallow gas monitoring and early warning system; 306, Integrated control pipeline bundle. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] As Figures 2 to 3 shown, the shallow gas monitoring and diverting device for offshore drilling of the present invention includes: a wellhead sealing and diverting device 100, a formation fluid monitoring and diverting device 200, and a remote control device 300.

[0041] Specifically, the wellhead sealing and diverting device 100 includes four parts: a drill pipe sealing assembly, a wellhead sealing housing, a reducing flange 105, and a wellhead diverting tee 106. The drill pipe sealing assembly penetrates through the wellhead sealing housing from top to bottom and maintains a seal. The lower end of the wellhead sealing housing is connected to the wellhead diverting tee 106 through the reducing flange 105, and the bottom of the wellhead diverting tee 106 is connected to the riser casing head; the third end of the wellhead diverting tee 106 is connected to the formation fluid monitoring and diverting device 200 through a main pipeline.

[0042] Among them, the drill pipe sealing assembly has two parts, an upper drill pipe and a lower drill pipe, which are connected by a rotating bearing in the middle. The upper drill pipe and the lower drill pipe are respectively surrounded and sealed by an upper drill pipe sealing rubber core 102 and a lower drill pipe sealing rubber core 104. The upper drill pipe sealing chamber formed by the drill pipe sealing assembly and the wellhead sealing housing is communicated with the rotating bearing. A cooling and lubricating inlet 101 is provided on the outer side wall of the upper drill pipe sealing chamber, and is connected to the cooling and lubricating inlet 101 through a cooling and lubricating hydraulic pipeline in the integrated control pipeline bundle 306 to cool the rotating bearing.

[0043] The wellhead sealing housing includes a housing body, a hydraulic clamp 103, a hydraulic cylinder manual locking device, and a grouting pipeline interface. Among them, the hydraulic control cylinder body on the hydraulic clamp 103 is connected to the clamp hydraulic control device 302 through a hydraulic pipeline in the integrated control pipeline bundle 306 to control the loosening and locking of the housing clamp. The supporting hydraulic cylinder manual locking device can manually lock the hydraulic cylinder after the housing clamp is locked. The side end of the wellhead sealing housing is respectively connected to the platform cementing pump and the cementing pipeline through unions, and each pipeline is connected to a manual stop valve (1# stop valve, 2# stop valve);

[0044] The reducing flange 105 installed at the lower part of the wellhead sealing housing mainly plays the role of flange reduction and elevation to ensure the smooth installation of the wellhead sealing housing; the wellhead diversion tee 106 is mainly connected to the riser casing head through a flange to realize the closed diversion of the drilling circulating fluid at the wellhead;

[0045] The function of the wellhead sealing and diversion device 100 is to seal the annular space between the drill string and the wellhead device, realize the closed diversion of the drilling circulating fluid at the wellhead, and is connected to the formation fluid monitoring and diversion device 200 through a flange, realizing the closed wellhead under all working conditions of drilling, circulating, tripping, and making connections.

[0046] As Figure 2 shown, the formation fluid monitoring and diversion device 200 includes a main pipeline 209, a pair of blowout prevention pipelines 210, a wellhead pressure monitoring sensor 201, remote video monitors 202 / 202″, gas detectors 203 / 203″, wind vanes 204 / 204″, ball valves 205, a gas source pipeline 206, a drilling pump stroke sensor 207, an electromagnetic flowmeter 208, a hydraulic stop valve A, a hydraulic stop valve B, a hydraulic stop valve C, a hydraulic stop valve D, a hydraulic stop valve E, and a hydraulic stop valve F.

[0047] One end of the main pipeline is connected to the third end of the wellhead flow - dividing tee 106. The wellhead pressure monitoring sensor 201 and the hydraulic plug valve A are connected in series on the main pipeline. The gas supply pipeline 206 is connected to the main pipeline through a tee, and a ball valve 205 is installed on the gas supply pipeline 206. An electromagnetic flowmeter 208 is also connected in parallel on the main pipeline. Hydraulic plug valves B and D are respectively arranged at both ends of the electromagnetic flowmeter 208. A hydraulic plug valve C is arranged at the position corresponding to the electromagnetic flowmeter 208 on the main pipeline. In addition, the blow - out prevention pipeline is communicated with the end of the main pipeline. The gas detector 203 is connected to the blow - out prevention pipeline 210 to detect the components of natural gas. Hydraulic plug valves E and F are respectively arranged at the input ends of the two blow - out prevention pipelines 210. The wind vane 204 is fixed on the outside of the blow - out prevention pipeline 210 to judge the wind direction.

[0048] Among them, the main pipeline is at least a 10 - inch pipeline. The main pipelines are connected to each other, the main pipeline is connected to the blow - out prevention pipeline, the pipelines are connected to the valves, and the pipelines are connected to the flowmeters through flanges. Both ends of the blow - out prevention pipeline must extend more than 2 m outside the drilling platform's hull. The end of the gas supply pipeline 206 must be welded with a quick - connector matching the platform gas source.

[0049] As Figure 2 、 Figure 3 As shown, the remote control device 300 includes a bearing cooling and lubrication device 301, a clamp hydraulic control device 302, a hydraulic plug valve control device 303, a remote video monitoring system 304, a micro - flow shallow gas monitoring and warning system 305, and an integrated control pipeline bundle 306. Among them, the integrated control pipeline bundle 306 includes hydraulic pipelines, lubricating oil pipelines, signal lines, and an outer pipeline protection sleeve.

[0050] Among them, the bearing cooling and lubrication device 301 is connected to the cooling and lubrication access port 101, and cools the rotating bearing in the wellhead sealing and flow - dividing device 100 through the cooling and lubrication pipeline located in the integrated control pipeline bundle 306.

[0051] The clamp hydraulic control device 302 is connected to the hydraulic clamp 103, and controls the hydraulic clamp 103 to loosen and lock through the hydraulic pipeline located in the integrated control pipeline bundle 306;

[0052] The hydraulic plug valve control device 303 is respectively connected to several hydraulic plug valves, and controls the opening and closing of the hydraulic plug valves A - F in the formation fluid monitoring and flow - dividing device 200 through the hydraulic pipeline located in the integrated control pipeline bundle 306;

[0053] The remote video monitoring system 304 can monitor the working status of each gate, the wind vane direction, and the flow rate of the drilling fluid at the outlet of the blow - out prevention pipeline in the formation fluid monitoring and flow - dividing device 200 in real time through the video transmission signal line located in the integrated control pipeline bundle 306;

[0054] The micro-flow shallow gas monitoring and early warning system 305 includes a micro-flow real-time monitoring module, an overflow and leakage cumulative total or segmented intelligent statistics and mathematical calculation model module, a combustible and toxic harmful gas real-time monitoring module, and a shallow gas intelligent comprehensive judgment and early warning module;

[0055] The micro-flow shallow gas monitoring and early warning system 305 collects the data transmitted by the wellhead pressure monitoring sensor 201, the gas detector 203 / 203″, the drilling pump stroke sensor 207, and the electromagnetic flowmeter 208 in the formation fluid monitoring and diversion device 200 through the signal transmission line in the integrated control pipeline bundle 306;

[0056] As Figure 4 shown, the present invention also discloses a method for monitoring and diverting shallow gas in offshore drilling, including:

[0057] S1: Determine the orientation of the blowout prevention pipeline of the shallow gas monitoring and diversion device for offshore drilling according to the sea area location where the drilling platform is located, the construction season, and the change law of the surface sea current and monsoon. The installation position of the blowout pipeline shall be along the direction of the monsoon.

[0058] S2: According to the magnitude of the formation leakage pressure P_leak of the adjacent well, perform simulation fitting calculations on different displacement, wellbore size, drill string assembly, and bottom hole pressure during the drilling process, and select the appropriate blowout pipeline size required for construction.

[0059] S3: Establish a circulating pressure loss calculation model, a bottom hole pressure calculation model, a leakage pressure calculation model, a wellbore stability calculation model, a fluctuating pressure calculation model, an overflow volume calculation model, and a leakage volume calculation model to conduct a risk assessment of the hazards of shallow gas;

[0060] S4: Through devices such as sensors, real-time collect the drilling pump stroke data, the real-time outlet flow value, the wellhead pressure value, and the drilling fluid outlet gas logging monitoring data. Through model fitting calculations, compare the inlet and outlet flows in real time, and through software comprehensive analysis, early detection and early warning of shallow gas can be achieved;

[0061] S5: Based on the loose geological structure of the offshore surface drilling, large drilled wellbore, high drilling displacement, and a large amount of sediment carried in the drilling fluid, which is extremely easy to block the pipeline, design a pipeline anti-blocking purging device, which can greatly reduce the risk of pipeline blockage;

[0062] S6: According to the change of the real-time wind direction, remotely control the blowout direction of the blowout pipeline in real time to avoid the combustible gas blowing against the platform against the wind and causing harm to the operating equipment and personnel.

[0063] This device can seal the wellhead in real time, preventing catastrophic accidents caused by the direct impact of shallow gas on the drilling platform due to improper human operation.

[0064] The installation steps of the marine drilling shallow gas monitoring and diversion device of the present invention will be further described in detail with reference to the accompanying drawings.

[0065] After the conductor casing is cemented during surface drilling of marine drilling, first, a cutting operation is performed on the riser. In order to ensure that the blowout preventer line is installed on the main deck, the electrician must accurately measure the cutting position.

[0066] After the riser is cut, install the riser casing head and the wellhead seal diversion device 100. After installation, fix the riser at the four corners with wire ropes to ensure that the center position of the wellhead seal diversion device is aligned with the rotary table, and the traveling block, rotary table, and wellhead are in a straight line with a deviation of no more than 10 mm to prevent early damage to the rubber core of the wellhead seal assembly.

[0067] After installing the formation fluid monitoring and diversion device 200, weld and fix the brackets supporting the pipeline and fix the main body of the pipeline with wire ropes.

[0068] Among them, when installing the blowout preventer line, both the front and rear ends must extend at least 2 m outside the drilling platform to prevent pollution to the platform; build a wellhead scaffolding to facilitate personnel to perform wellhead installation operations; install the remote control device 300 and install and connect the integrated control pipeline bundle 306.

[0069] The working principle and working process of the marine drilling shallow gas monitoring and diversion device and method of the present invention will be briefly described below with reference to the accompanying drawings.

[0070] The present invention provides a marine drilling shallow gas monitoring and diversion device. In view of the characteristics of shallow gas that may be encountered during marine drilling, such as being difficult to predict, having a relatively high formation pressure, shallow burial depth, and great harm, combined with the backward technology and inconvenient operation of existing shallow gas prevention equipment, which cannot monitor the discovery of early shallow gas and poses great potential safety hazards, a new technical solution for marine drilling shallow gas monitoring and diversion is proposed. Based on the original technical solution for shallow gas prevention, by inventing a new type of wellhead seal diversion device, micro-flow shallow gas monitoring device, remote rapid diversion and blowout device, and pipeline anti-blocking device, a remote monitoring and control module is invented, which realizes the early discovery of shallow gas in a closed wellhead environment, quickly judges it, and quickly actuates the relevant valve states for rapid blowout, which can fundamentally solve the harm caused by shallow gas to the drilling platform and personnel, achieve early discovery and early prevention, provide valuable basis for the formulation of the technical solution of the project team, and win valuable time for platform emergency and well killing operations.

[0071] The present invention provides a method for monitoring and diverting shallow gas in offshore drilling. By adopting the micro-flow method, it can quickly judge the early discovery of shallow gas, thereby improving the drilling efficiency and well control safety. At the same time, by optimizing the pipeline installation, the safety of personnel and equipment on the offshore platform can be greatly improved. This method can be widely applied to the field of offshore drilling.

[0072] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An offshore drilling shallow gas monitoring and diversion device, characterized in that, it includes a wellhead sealing and diversion device (100), a formation fluid monitoring and diversion device (200), and a remote control device (300); The wellhead sealing and diversion device (100) includes a drill pipe sealing assembly, a wellhead sealing housing, a reducing flange (105), and a wellhead diversion tee (106); the drill pipe sealing assembly penetrates through the wellhead sealing housing from top to bottom and maintains a seal, and the lower end of the wellhead sealing housing is connected to the wellhead diversion tee (106) through the reducing flange (105), and the bottom of the wellhead diversion tee (106) is connected to the riser casing head; The formation fluid monitoring and diversion device (200) includes a main pipeline (209), a blowout prevention pipeline (210), a remote video monitor (202), a gas source pipeline (206), and a number of hydraulic plug valves; one end of the main pipeline (209) is connected to the third end of the wellhead diversion tee (106), and a wellhead pressure monitoring sensor (201), an electromagnetic flowmeter (208), the gas source pipeline (206), and the blowout prevention pipeline (210) are connected to the main pipeline (209), and a ball valve (205) is installed on the gas source pipeline (206), and a gas detector (203) is connected to the blowout prevention pipeline (210); The remote control device (300) includes a hydraulic plug valve control device (303), a remote video monitoring system (304), and a micro-flow shallow gas monitoring and warning system (305); a number of the hydraulic plug valves are respectively connected to the hydraulic plug valve control device (303) through hydraulic pipelines, and the remote video monitoring system (304) is connected to the remote video monitor (202) through a signal transmission line; the micro-flow shallow gas monitoring and warning system (305) is connected to the wellhead pressure monitoring sensor (201), the gas detector (203), and the electromagnetic flowmeter (208) through signal transmission lines.

2. The offshore drilling shallow gas monitoring and diversion device according to claim 1, characterized in that, the drill pipe sealing assembly has an upper drill pipe and a lower drill pipe, and the upper drill pipe and the lower drill pipe are connected by a rotating bearing in the middle; the upper drill pipe is surrounded and sealed by an upper drill pipe sealing rubber core (102), and the lower drill pipe is surrounded and sealed by a lower drill pipe sealing rubber core (104).

3. The offshore drilling shallow gas monitoring and diversion device according to claim 2, characterized in that, a cooling and lubricating inlet (101) is provided on the side wall of the upper drill pipe sealing chamber formed by the drill pipe sealing assembly and the wellhead sealing housing, and the cooling and lubricating inlet (101) is connected to a bearing cooling and lubricating device (301) in the remote control device (300) through a cooling and lubricating hydraulic pipeline.

4. The offshore drilling shallow gas monitoring and diversion device according to claim 1, characterized in that, The wellhead sealing housing includes a housing main body, a hydraulic clamp (103), and a grouting pipeline interface; wherein, a hydraulic cylinder body on the hydraulic clamp (103) is connected to a clamp hydraulic control device (302) in the remote control device (300) through a hydraulic pipeline.

5. The marine drilling shallow gas monitoring and diversion device according to claim 4, characterized in that the wellhead sealing housing further includes a hydraulic cylinder manual locking device that matches the hydraulic clamp (103).

6. The marine drilling shallow gas monitoring and diversion device according to claim 1, characterized in that a hydraulic rotary plug valve is respectively arranged at both ends of the electromagnetic flowmeter (208); a hydraulic rotary plug valve is provided at a position corresponding to the electromagnetic flowmeter (208) on the main pipeline (209).

7. The marine drilling shallow gas monitoring and diversion device according to claim 1, characterized in that the formation fluid monitoring and diversion device (200) further includes a drilling pump stroke sensor (207), and the drilling pump stroke sensor (207) is connected to the micro-flow shallow gas monitoring and early warning system (305) through a signal transmission line.

8. The marine drilling shallow gas monitoring and diversion device according to claim 1, characterized in that a wind vane (204) is fixed on the outside of the blowout prevention pipeline (210).

9. The marine drilling shallow gas monitoring and diversion device according to claim 1, characterized in that the micro-flow shallow gas monitoring and early warning system (305) includes a micro-flow real-time monitoring module, an overflow and loss cumulative total or segmented intelligent statistical and mathematical calculation model module, a combustible and toxic and harmful gas real-time monitoring module, and a shallow gas intelligent comprehensive judgment and early warning module.

10. A method for monitoring and diverting shallow gas in marine drilling, characterized in that it is realized by using the marine drilling shallow gas monitoring and diversion device according to any one of claims 1 to 9, and includes the following steps: S1: Determine the orientation of the blowout prevention pipeline according to the sea area position where the drilling platform is located, the season to which the construction belongs, and the change rules of the surface sea current and monsoon; S2: According to the magnitude of the formation leakage pressure P_leak of the adjacent well, conduct simulation fitting calculations on different displacement, wellbore size, drill string combination, and bottom hole pressure during the drilling process, and select the size of the blowout prevention pipeline suitable for the construction requirements; S3: Establish a circulating pressure loss calculation model, a bottom hole pressure calculation model, a leakage pressure calculation model, a wellbore stability calculation model, a fluctuation pressure calculation model, an overflow volume calculation model, and a leakage volume calculation model to conduct a risk assessment on the hazards of shallow gas; S4: Through sensors and other devices, real-time collect drilling pump stroke data, outlet real-time flow rate values, wellhead pressure values, and drilling fluid outlet gas logging monitoring data, conduct real-time comparison of the inlet and outlet flow rates through model fitting calculations, and conduct comprehensive analysis through software to realize early detection and early warning of shallow gas; S5: Design a pipeline anti-blocking and purging device based on the characteristics of loose geological structure on the marine surface during drilling, large open wellbore, high drilling displacement, and a large amount of sediment carried in the drilling fluid; S6: According to the change of the real-time wind direction, remotely control the blowout direction of the blowout prevention pipeline in real time.

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