CN114622892A - Automatic well killing simulation device for pressure-controlled drilling and fine control back pressure method - Google Patents

Abstract

The invention provides an automatic kill simulation device for pressure-controlled drilling and a fine control back pressure method, wherein the automatic kill simulation device comprises a sleeve, a drill rod, a wellhead sleeve pressure sensor, a riser pressure sensor, a bottom hole pressure sensor, a pressure sensor in a well, a gas-liquid flowmeter, a gas injection unit, a coiling unit, an industrial control unit and a throttle valve, wherein the wellhead sleeve is communicated with the sleeve; the pressure of the wellhead casing, the pressure sensor of the riser, the pressure sensor of the shaft bottom and the pressure sensor of the well are respectively tested by the pressure sensor of the wellhead casing, the pressure sensor of the riser, the pressure sensor of the shaft bottom and the pressure sensor of the well, the flow of the wellhead casing is measured by the gas-liquid flowmeter, and the throttle valve opens and closes the wellhead casing; the gas injection unit injects gas into the annular space; the wire coiling unit pulls up and lowers the drill rod; the industrial control unit is respectively connected with the gas injection unit, the winding unit and the throttle valve and collects pressure data of each position. The invention has the advantages of simulating the back pressure of the working conditions of drill tripping, drill tripping and overflow and leakage under the pressure control environment and the like.

Description

An automatic well killing simulation device for managed pressure drilling and a method for finely controlling back pressure

technical field

The invention relates to the technical field of oil and natural gas managed pressure drilling, in particular to an automatic well killing simulation device for managed pressure drilling and a method for finely controlling back pressure.

Background technique

Managed pressure drilling technology is an important technology used to solve working conditions such as narrow density window and coexistence of spillage. ;Due to the valve action, unstable flow will occur at the wellhead, resulting in pressure fluctuations at the wellhead, and periodic fluctuations in pressure can be transmitted to the wellbore, thereby affecting the wellbore pressure; Excessive valve fluctuation pressure will erode the valve core, resulting in The valve core is damaged.

The patent application number is "CN101852076B" and the title is "the method and device for simulating downhole working conditions for managed pressure drilling experiment and testing". Changes in operating conditions, including: normal drilling, switching on and off the mud pump, tripping, lost circulation, kick and other operating conditions, the MPD equipment can automatically judge and identify the operating conditions and control the pressure changes according to the changes in the operating conditions. , keep the simulated bottom hole pressure constant, and avoid the occurrence of abnormal situations such as lost circulation and kick. The drilling fluid flow rate and density are input through mud pump A, and the opening of choke valve B is adjusted to simulate the bottom hole pressure fluctuation; the choke manifold simulates the pressure loss of the wellbore annulus; the opening of choke valve A is adjusted to simulate the lost circulation condition; Start the mud pump B or the gas source, control the input flow, and simulate the kick condition. Accurately grasp the MPD parameters and debug the MPD equipment in detail. However, this device does not have a calculation method to control the peak value of the maximum fluctuating pressure by controlling the adjustment time of the blowout preventer/throttle valve, and cannot simulate the back pressure control of the multiphase tripping and tripping conditions during the pressure control process.

At present, soft shut-in, hard shut-in, and semi-soft shut-in are often used to deal with the occurrence of drilling overflow, which all involve the fluctuating pressure caused by the change of the opening of the blowout preventer/throttle valve; within a certain pressure range, if the fluctuating pressure is reduced The maximum peak value can not only prolong the life of the blowout preventer/throttle valve, but also finely control the fluctuating pressure of the wellbore to meet the needs of narrow-window drilling; the corresponding gas-liquid two-phase/single-phase fluctuating pressure/water hammer models have been established at home and abroad, which can Calculate the peak value of the maximum fluctuating pressure generated by the action of the blowout preventer or valve. However, there is currently no calculation method to control the peak value of the maximum fluctuating pressure by controlling the adjustment time of the blowout preventer/throttle valve. This control process does not realize the experimental analysis of the simulated device. In particular, there is a lack of a backpressure control simulation device for multiphase tripping and tripping conditions in the pressure control process.

To sum up, the existing MPD simulation devices and methods have the following problems:

①The conventional bench can simulate the drilling, overflow, lost circulation and other working conditions, but it cannot simulate the drilling and running conditions of multiphase flow in the wellbore under the pressure-controlled environment;

②There is no calculation method to control the peak value of the maximum fluctuating pressure in the valve adjustment during the killing process;

③ The regulating valve adopts the adaptive mode, and there is no planned staged control mode according to the smooth curve;

④ The calculation model of back pressure under different working conditions of MPD does not consider the fluctuating pressure.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the above deficiencies of the prior art. For example, one of the objectives of the present invention is to provide a managed pressure drilling automatic kill simulation device capable of simulating the tripping and tripping conditions of a wellbore multiphase flow in a managed pressure environment. For another example, another object of the present invention is to provide a method for controlled pressure drilling, automatic well kill and fine control back pressure, capable of simulating the tripping and running conditions of multiphase flow in a wellbore under a managed pressure environment.

In order to achieve the above object, one aspect of the present invention provides an automatic well kill simulation device for managed pressure drilling. The automatic well kill simulation device includes a casing, a drill pipe, a wellhead casing, a wellhead casing pressure sensor, and a riser pressure. Sensor, bottom hole casing pressure sensor, bottom hole pressure sensor, downhole pressure sensor, gas-liquid flowmeter, gas injection unit, reeling unit, industrial control unit and choke valve, wherein,

The casing is arranged in the simulated wellbore, the drill pipe is arranged in the casing, and the wellhead casing is arranged on the casing and communicates with the annulus between the inner wall of the casing and the outer wall of the drill pipe;

The wellhead casing pressure sensor can measure the pressure of the wellhead casing, the gas-liquid flowmeter can measure the flow rate of the drilling fluid in the wellhead casing, and the choke valve can control the wellhead casing wellhead. Opening and closing;

The riser pressure sensor can measure the pressure of the drilling fluid in the drill pipe, the in-well pressure sensor can measure the pressure in the middle of the casing, and the bottom-hole pressure sensor can measure the bottom-hole pressure;

The gas injection unit is capable of injecting gas into the annulus to simulate downhole gas overflow invasion;

The wire reeling unit can pull up and run down the drill pipe to simulate the tripping and tripping process;

The industrial control unit is respectively connected with the wellhead casing pressure sensor, the riser pressure sensor, the bottom hole pressure sensor, the well pressure sensor, the gas injection unit, the reeling unit and the choke valve to collect the wellhead casing pressure sensor, Pipe pressure sensor, bottom hole pressure sensor and downhole pressure sensor test pressure data, and control the gas injection unit, reel unit and choke valve.

In an exemplary embodiment of an aspect of the present invention, the automatic well kill simulation device may further include a drilling fluid leakage unit, and the drilling fluid leakage unit is disposed at the bottom of the simulated wellbore to simulate drilling fluid leakage.

In an exemplary embodiment of an aspect of the present invention, the automatic well kill simulation device may further include a drilling fluid weighing unit, which is capable of automatically weighing the leakage amount of the drilling fluid.

In an exemplary embodiment of an aspect of the present invention, the automatic kill simulation device may further include a drilling pump that pumps drilling fluid into the drill pipe.

Another aspect of the present invention provides a method for finely controlling the back pressure of a managed pressure drilling automatic well kill. Control the back pressure of the tripping condition, the MPD running condition and/or the MPD overflow and kill condition.

In an exemplary embodiment of another aspect of the present invention, the back pressure control of the MPD tripping condition may include the steps of:

Control the reeling unit to pull up the drill pipe through the industrial control unit to simulate the swabbing pressure generated during the tripping process;

The gas injection unit is controlled by the industrial control unit to inject gas into the bottom of the well to simulate the multiphase flow field in the wellbore;

The opening of the choke valve is controlled by the industrial control unit to simulate the wellhead back pressure of the managed pressure drilling during the tripping process;

The industrial control unit collects the swabbing pressure during the tripping process in real time through the wellhead casing pressure sensor, the riser pressure sensor, the well pressure sensor and the bottom hole pressure sensor;

The real-time back pressure of the MPD tripping process is calculated by formula 1,

Formula 1 is:

p _b ^(t1) = p _w ^(t1) - p _h ^(t1) - p _f ^(t1) + p _s ^(t1) + p _k ^(t1)

Among them, p _b ^(t1) is the real-time back pressure in the tripping condition, Mpa; _pw ^(t1) is the real-time bottom hole pressure in the tripping condition, Mpa; p _h ^(t1) is the real-time hydrostatic column pressure in the tripping condition , Mpa; p _f ^(t1) is the real-time frictional resistance in the tripping condition, Mpa; p _s ^(t1) is the real-time swabbing pressure in the tripping condition, Mpa; p _k ^(t1) is the throttle valve adjustment in the tripping condition The resulting fluctuating pressure, MPa.

In an exemplary embodiment of another aspect of the present invention, the back pressure control of the MPD drilling condition may include the steps of:

Control the reeling unit to lower the drill pipe through the industrial control unit to simulate the exciting pressure generated during the drilling process;

The gas injection unit is controlled by the industrial control unit to inject gas into the bottom of the well to simulate the multiphase flow field in the wellbore during the drilling process;

The opening of the choke valve is controlled by the industrial control unit to simulate the wellhead back pressure of the managed pressure drilling during the drilling process;

The industrial control unit collects the excitation pressure during the drilling process in real time through the wellhead casing pressure sensor, the riser pressure sensor, the downhole pressure sensor and the bottom hole pressure sensor;

The real-time back pressure of the MPD under drilling conditions is calculated by formula 2,

Formula 2 is:

p _b ^(t2) = p _w ^(t2) -p _h ^(t2) -p _f ^(t2) -p _g ^(t2) +p _k ^(t2)

Among them, p _b ^(t2) is the real-time back pressure under drilling conditions, Mpa; p _w ^(t2) is the real-time bottom hole pressure under drilling conditions, Mpa; p _h ^(t2) is the real-time hydrostatic column pressure under drilling conditions , Mpa; p _f ^(t2) is the real-time frictional resistance under the drilling condition, Mpa; p _g ^(t2) is the real-time excitation pressure under the drilling condition, Mpa; p _k ^(t2) is the adjustment generated by the throttle valve under the drilling condition fluctuating pressure, MPa.

In an exemplary embodiment of another aspect of the present invention, the back pressure control of the MPD overflow and kill condition may include the steps of:

The gas injection unit is controlled by the industrial control unit to inject gas into the bottom of the well to simulate the multiphase flow field in the wellbore during the overflow invasion process;

The opening of the choke valve is controlled by the industrial control unit to simulate the choke cycle and blowout of the managed pressure drilling in the process of overflow and well killing;

Open the overflow unit through the industrial control unit, simulate the loss of drilling fluid during the overflow killing process, and obtain the loss of drilling fluid;

The opening of the choke valve is controlled by the industrial control unit to simulate the wellhead back pressure of the managed pressure drilling during the overflow invasion process;

The industrial control unit collects the gas slippage pressure drop in the process of overflow and kill through the wellhead casing pressure sensor, riser pressure sensor, downhole pressure sensor and bottom hole pressure sensor in real time; The pressure is calculated by Equation 3,

Formula 3 is:

p _b ^(t3) = p _w ^(t3) - p _h ^(t3) - p _f ^(t3) - p _m ^(t3) + p _k ^(t3)

Among them, p _b ^(t3) is the real-time back pressure under overflow and kill conditions, Mpa; p _w ^(t3) is the real-time bottom hole pressure under overflow and kill conditions, Mpa; p _h ^(t3) is the overflow and kill work conditions The real-time hydrostatic column pressure, Mpa; p _f ^(t3) is the real-time frictional resistance under the overflow and kill condition, Mpa; p _m ^(t3) is the real-time gas slippage pressure drop under the overflow and kill condition, Mpa; p _k ^{( t3)} is the fluctuating pressure generated by the throttle valve adjustment, MPa.

In an exemplary embodiment of another aspect of the present invention, the real-time frictional resistance of the tripping condition, the drilling condition, and the overflow and kill condition can be calculated by Equation 4,

Formula 4 is:

h _f =λlu ² /2d

Among them, h _f is the real-time frictional resistance of the tripping condition, the drilling condition, and the overflow and kill condition, Mpa; λ is the frictional resistance coefficient; l is the casing length, m; u is the speed, m/s.

In an exemplary embodiment of another aspect of the present invention, the fluctuating pressure generated by the throttle valve adjustment in the tripping, tripping and overflow conditions is calculated by Equation 5,

Formula 5 is:

c ⁺ :H _i+1 =H _i -B(Q _i+1 -Q _i )-RQ _i |Q _i | (5-1)

c ⁻ : H _i =H _i+1 -B(Q _i -Q _i+1 )+RQ _i+1 |Q _i+1 | (5-2)

Among them, B is the transfer parameter value c/(g·A); R is the transfer parameter value; c ⁺ : H _i+1 represents the fluctuating pressure along the v+c direction, MPa; c ⁻ : H _i represents the fluctuating pressure along the vc direction , MPa; Q(i) is the flow rate at unit i, m ³ /s; Q(i+1) is the flow rate at unit i+1, m ³ /s.

In an exemplary embodiment of another aspect of the present invention, the flow rate of the throttle valve can be calculated by Equation 6,

Formula 6 is:

where Q(j) is the flow at unit j, m ³ /s; Q(i) is the flow at unit i, m ³ /s; Q(i+1) is the flow at unit i+1, m ³ /s; O is the throttle valve opening coefficient.

In an exemplary embodiment of another aspect of the present invention, the opening degree of the throttle valve can be calculated by formula 7,

Formula 7 is:

Among them, τ(j) is the opening of the throttle valve; Q ₀ is the initial flow, m ³ /s; Q(in , _j ) is the flow at the unit j at the wellhead, m ³ /s; T _max is the throttle Valve limiting pressure time, s; Δt is the throttle valve adjustment interval, s; ζ is the throttle valve flow coefficient; H(in , _j ) is the wellhead pressure head, m.

Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

(1) The present invention provides an automatic well kill simulation device for managed pressure drilling, which can simulate working conditions such as tripping, drilling, and overflow killing of wellbore multiphase flow in a controlled pressure environment;

(2) The present invention provides a method for precise control of back pressure by automatic killing of wells in managed pressure drilling, and a method for calculating the peak value of the maximum fluctuating pressure in valve adjustment control, which avoids excessive valve fluctuating pressure from causing the valve core. Erosion and damage to the valve core;

(3) The present invention provides a method for precise control of back pressure by automatic well killing in managed pressure drilling, and a method for planned and staged control according to a smooth curve in valve adjustment control;

(4) The present invention provides a method for precise control of back pressure by automatic well killing in managed pressure drilling, and the influence of fluctuating pressure is considered in the calculation model of back pressure in different working conditions of managed pressure drilling.

Description of drawings

The above and other objects and/or features of the present invention will become more apparent from the following description in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a schematic structural diagram of an automatic well kill simulation device for managed pressure drilling according to an exemplary embodiment of the present invention.

Description of reference numbers:

1-wellhead casing pressure sensor, 2-standpipe pressure sensor, 3-gas-liquid flowmeter, 4-throttle valve, 5-industrial control unit, 6-wellhead casing, 7-casing, 8-drill pipe, 9 -Simulated wellbore, 10-winding unit, 11-gas injection unit, 12-drilling fluid leakage unit, 13-drilling fluid weighing unit, 14-bottom hole pressure sensor, 15-well pressure sensor, 16-simulated wellbore .

Detailed ways

Hereinafter, the MPD automatic kill simulation device and the fine control back pressure method of the present invention will be described in detail with reference to the exemplary embodiments.

In the first exemplary embodiment of the present invention, the MPD automatic well kill simulation device mainly includes casing, drill pipe, wellhead casing, wellhead casing pressure sensor, riser pressure sensor, bottom hole pressure sensor, well pressure sensor Sensors, gas-liquid flow meters, gas injection units, reeling units, industrial control units and throttle valves.

The casing is arranged in the simulated wellbore, the drill pipe is arranged in the casing, and an annulus for drilling fluid circulation is formed between the inner wall of the casing and the outer wall of the drill pipe and at the bottom of the well. One end of the wellhead casing is connected with the casing, and the other end is connected with the drilling fluid storage tank, which circulates the drilling fluid in the annulus to the drilling fluid storage tank.

The wellhead casing pressure sensor is set on the wellhead casing to measure the pressure of the drilling fluid returned, and the gas-liquid flowmeter is set on the wellhead casing to measure the flow rate of the drilling fluid in the wellhead casing. The choke valve is set on the wellhead casing to open and close the wellhead casing to simulate the influence of the pressure fluctuation generated by the valve on the wellhead back pressure during the well killing process. Here, the wellhead casing pressure sensor and the gas-liquid flowmeter are arranged before the choke valve, and the choke valve may be a hydraulic control valve.

The riser pressure sensor is arranged on the drill pipe to be able to measure the pressure of the drilling fluid in the drill pipe, and the well pressure sensor is arranged in the middle of the casing to measure the pressure in the middle of the casing. Bottom hole pressure sensors are placed at the bottom of the well or casing to measure the bottom hole pressure. Here, the wellhead casing pressure sensor, the riser pressure sensor, the bottom hole pressure sensor, and the downhole pressure sensor may include a set of pressure sensors composed of a plurality of pressure sensors to more accurately measure the pressure at each location.

The gas injection unit is connected to the bottom of the simulated wellbore to inject gas to the bottom of the wellbore to simulate the multiphase flow law of the formation gas entering the bottomhole and migrating along the annulus.

The reeling unit can pull up and run down the drill pipe to simulate the tripping and running process. Here, the wire winding unit includes a pulley and a wire winding device, the pulley is fixedly arranged, and the pulling wire of the wire winding device is connected to the upper part of the drill pipe through the pulley.

The industrial control unit is respectively connected with the wellhead casing pressure sensor, the riser pressure sensor, the bottom hole pressure sensor, the downhole pressure sensor, the gas injection unit and the reeling unit to collect the wellhead casing pressure sensor, riser pressure sensor, bottom hole pressure sensor, Pressure data at various locations measured by the pressure sensor in the well. The industrial computer can also control the gas injection unit and the reeling unit to control the drilling, drilling and spilling processes.

In this exemplary embodiment, the automatic well kill simulation device may further include a drilling fluid leakage unit, and the drilling fluid leakage unit is disposed at the bottom of the simulated wellbore to simulate drilling fluid leakage.

In this exemplary embodiment, the automatic well kill simulation device may further include a drilling fluid weighing unit, which is capable of automatically weighing the leakage amount of the drilling fluid.

In this exemplary embodiment, the automatic kill simulation device may further include a drilling pump that pumps drilling fluid into the drill pipe.

FIG. 1 shows a schematic structural diagram of an automatic well kill simulation device for managed pressure drilling according to an exemplary embodiment of the present invention.

In the second exemplary embodiment of the present invention, as shown in FIG. 1 , the MPD automatic well kill simulation device mainly includes casing 7 , drill pipe 8 , wellhead casing 6 , wellhead casing pressure sensor 1 , vertical Pipe pressure sensor 2 , bottom hole pressure sensor 14 , downhole pressure sensor 15 , gas-liquid flow meter 3 , gas injection unit 11 , reeling unit 10 , industrial control unit 5 and throttle valve 4 .

The casing 7 is set in the simulated wellbore 16 , the drill pipe 8 is set in the casing 7 , and a drilling fluid circulation is formed between the inner wall of the casing 7 and the outer wall of the drill pipe 8 and the bottom of the simulated wellbore 16 the annular space. One end of the wellhead casing 6 is connected to the casing 7, and the other end is connected to the drilling fluid storage tank, so as to circulate the drilling fluid in the annulus to the drilling fluid storage tank.

The wellhead casing pressure sensor 1 is arranged on the wellhead casing 6 to measure the pressure of the drilling fluid returned, and the gas-liquid flow meter 3 is arranged on the wellhead casing 6 to measure the flow rate of the drilling fluid in the wellhead casing 6 . The choke valve 4 is arranged on the wellhead casing 6 to open and close the drilling fluid in the wellhead casing 6, simulating the influence of the pressure fluctuation generated by the valve during the killing process on the wellhead back pressure. Here, the wellhead casing pressure sensor 1 and the gas-liquid flow meter 3 are both arranged before the throttle valve 4, and the throttle valve 4 may be a hydraulic control valve.

The riser pressure sensor 2 is provided on the drill pipe 8 to measure the pressure of the drilling fluid in the drill pipe 8 . The downhole pressure sensor 15 is provided at the middle position of the casing 7 to measure the pressure in the middle of the casing 7 (ie, the pressure at the downhole position). A bottom hole pressure sensor 14 is placed at the bottom of the simulated wellbore 16 or the bottom of the casing 7 to measure the pressure at the bottom hole location. Here, the wellhead casing pressure sensor 1, the riser pressure sensor 2, the bottom hole pressure sensor 14 and the downhole pressure sensor 15 may include a set of pressure sensors composed of a plurality of pressure sensors to more accurately measure the pressure at each location.

The gas injection unit 11 is communicated with the bottom of the simulated wellbore 16 to inject gas to the bottom of the well, so as to simulate the multiphase flow law in the process of formation gas entering the bottom of the well and migrating along the annulus.

The reeling unit 10 is capable of pulling up and lowering the drill pipe to simulate the tripping and tripping process. Here, the wire winding unit 10 includes a pulley and a wire winding device, the pulley is fixedly arranged, and the pulling wire of the wire winding device is connected to the upper part of the drill pipe 8 through the pulley.

The industrial control unit 5 is respectively connected with the wellhead casing pressure sensor 1, the riser pressure sensor 2, the bottom hole pressure sensor 14, the well pressure sensor 15, the gas injection unit 11, the reeling unit 10 and the choke valve 4 to collect the wellhead casing pressure Pressure data at various positions measured by sensor 1 , riser pressure sensor 2 , bottom hole pressure sensor 14 , and downhole pressure sensor 15 . The industrial control unit 5 can also control the gas injection unit 11, the reeling unit 10 and the throttle valve 4 to simulate the process of tripping, tripping and overflowing. In this exemplary embodiment, as shown in FIG. 1 , the automatic well kill simulation device may further include a drilling fluid leakage unit 12 , which is disposed at the bottom of the simulated wellbore 16 to simulate drilling fluid leakage. For example, the drilling fluid leakage unit 12 may be a drilling fluid leakage valve.

In the present exemplary embodiment, as shown in FIG. 1 , the automatic well kill simulation device may further include a drilling fluid weighing unit 13 , and the drilling fluid weighing unit 13 can automatically measure the leakage amount of the drilling fluid.

In this exemplary embodiment, the automatic kill simulation device may further include a drilling pump that pumps drilling fluid into the drill pipe.

In the third exemplary embodiment of the present invention, in the method for finely controlling the back pressure of the MPD automatic well killing, the controlled pressure drilling can be controlled by the MPD automatic killing simulation device described in the first or second exemplary embodiment above. The drilling and tripping conditions, the controlled pressure drilling running conditions and the managed pressure drilling overflow and killing conditions are simulated, and the corresponding back pressure calculation method is proposed according to different working conditions to achieve the purpose of real-time balancing of the bottom hole pressure.

In the present exemplary embodiment, the fine managed pressure method for simulating the MPD tripping condition may include the steps of:

The drill pipe is pulled up by controlling the reeling unit through the industrial control unit to simulate the swabbing pressure generated during the tripping process. Control the pulling speed of the drill pipe during the pulling process. Here, the pull-up speed of the drill pipe is generally controlled at 0.1-0.8m/s. By controlling the pull-up speed, the swabbing pressure generated by tripping is simulated. Excessive swabbing pressure during tripping is prone to overflow. The gas injection unit is controlled by the industrial control unit to inject gas into the bottom of the well to simulate the multiphase flow field in the wellbore.

The opening of the choke valve is controlled by the industrial control unit to simulate the influence of the adjustment time of the choke valve on the wellhead back pressure of the managed pressure drilling during the tripping process. During the tripping process, the industrial control unit collects the swabbing pressure during the tripping process in real time through four sets of pressure sensors: wellhead casing pressure sensor, riser pressure sensor, downhole pressure sensor and bottom hole pressure sensor.

The real-time back pressure of the MPD tripping process is calculated by Equation 1,

Formula 1 is:

p _b ^(t1) = p _w ^(t1) - p _h ^(t1) - p _f ^(t1) + p _s ^(t1) + p _k ^(t1)

Among them, p _b ^(t1) is the real-time back pressure of the tripping condition, Mpa; _pw ^(t1) is the real-time bottom hole pressure (measured by the bottom hole pressure sensor) under the tripping condition, Mpa; p _h ^(t1) is Real-time hydrostatic column pressure in tripping condition, Mpa; p _f ^(t1) is real-time frictional resistance in tripping condition, Mpa; p _s ^(t1) is real-time swabbing pressure in tripping condition, Mpa; p _k ^(t1) The fluctuating pressure generated by the throttle valve adjustment for the tripping condition, MPa.

In the present exemplary embodiment, the fine-controlled pressure method for simulating the running condition of MPD may include the steps of:

The drill pipe is lowered by controlling the reeling unit through the industrial control unit to simulate the exciting pressure generated during the drilling process. Control the lowering speed of the drill pipe during the lowering process. Here, the lowering speed of the drill pipe is generally controlled in the range of 0.1-0.5m/s during the drilling process. The excitation pressure generated by the drilling is simulated by controlling the lowering speed of the drill pipe. During the drilling process, the excitation pressure is too large and it is easy to cause lost circulation.

The gas injection unit is controlled by the industrial control unit to inject gas into the bottom of the well to simulate the multiphase flow field in the wellbore during the drilling process;

The opening of the choke valve is controlled by the industrial control unit to simulate the wellhead back pressure of the managed pressure drilling during the drilling process;

The industrial control unit collects the excitation pressure in the process of drilling in real time through four sets of pressure sensors: wellhead casing pressure sensor, riser pressure sensor, downhole pressure sensor and bottom hole pressure sensor;

The real-time back pressure of the MPD drilling process is calculated by Equation 2,

Formula 2 is:

p _b ^(t2) = p _w ^(t2) -p _h ^(t2) -p _f ^(t2) -p _g ^(t2) +p _k ^(t2)

Among them, p _b ^(t2) is the real-time back pressure under the drilling condition, Mpa; p _w ^(t2) is the real-time bottom-hole pressure (measured by the bottom-hole pressure sensor) under the drilling condition, Mpa; p _h ^(t2) is the down-hole pressure Real-time hydrostatic column pressure under drilling conditions, Mpa; p _f ^(t2) is the real-time frictional resistance under drilling conditions, Mpa; p _g ^(t2) is real-time excitation pressure under drilling conditions, Mpa; p _k ^(t2) is the real-time excitation pressure under drilling conditions The fluctuating pressure generated by the throttle valve adjustment in drilling conditions, MPa.

In this exemplary embodiment, the fine-controlled pressure method for simulating the well-overflow and kill-off condition of managed pressure drilling may include the steps of:

The gas injection unit is controlled by the industrial control unit to inject gas to the bottom of the well, and the gas migrates to the wellhead along the annulus, simulating the multiphase flow field in the wellbore during the overflow invasion process.

The opening of the choke valve is controlled by the industrial control unit to simulate the choke cycle and blowout of the managed pressure drilling in the process of overflow and leakage killing.

Open the overflow unit through the industrial control unit, simulate the loss of drilling fluid during the process of overflow and kill well, and obtain the loss of drilling fluid.

The opening of the choke valve is controlled by the industrial control unit to simulate the wellhead back pressure of the managed pressure drilling during the overflow invasion process. The industrial control unit collects the gas slippage pressure drop in the process of leaking and killing in real time through four sets of pressure sensors, namely wellhead casing pressure sensor, riser pressure sensor, downhole pressure sensor and bottom hole pressure sensor;

The real-time back pressure of the managed pressure drilling overflow, leakage and kill condition is calculated by formula 3,

Formula 3 is:

p _b ^(t3) = p _w ^(t3) - p _h ^(t3) - p _f ^(t3) - p _m ^(t3) + p _k ^(t3)

Among them, p _b ^(t3) is the real-time back pressure under overflow and kill conditions, Mpa; p _w ^(t3) is the real-time bottom hole pressure under overflow and kill conditions, Mpa; p _h ^(t3) is the overflow and kill work conditions The real-time hydrostatic column pressure, Mpa; p _f ^(t3) is the real-time frictional resistance under the overflow and kill condition, Mpa; p _m ^(t3) is the real-time gas slippage pressure drop under the overflow and kill condition, Mpa; p _k ^{( t3)} is the fluctuating pressure generated by the throttle valve adjustment, MPa.

The real-time friction resistance of the tripping condition, the drilling condition, and the overflow and kill condition can be calculated by Equation 4,

Formula 4 is:

h _f =λlu ² /2d

Among them, h _f is the real-time frictional resistance of the tripping condition, the drilling condition, and the overflow and kill condition, Mpa; λ is the frictional resistance coefficient; l is the casing length, m; u is the speed, m/s. The hydrostatic column pressure is calculated by ph = _ρgh , where ρ is the drilling fluid density, g/cm ³ ; g is the acceleration of gravity, N/kg; h is the vertical depth, m.

In this exemplary embodiment, the fluctuating pressure generated by the throttle valve adjustment in the tripping condition, the drilling condition and the overflow kill condition can be calculated by Equation 5,

Formula 5 is:

c ⁺ :H _i+1 =H _i -B(Q _i+1 -Q _i )-RQ _i |Q _i | (5-1)

c ⁻ : H _i =H _i+1 -B(Q _i -Q _i+1 )+RQ _i+1 |Q _i+1 | (5-2)

Among them, B is the transfer parameter value c/(g·A); R is the transfer parameter value; c ⁺ : H _i+1 represents the fluctuating pressure along the v+c direction; c ⁻ : H _i represents the fluctuating pressure along the vc direction; Q (i) is the flow rate at unit i, m ³ /s; Q(i+1) is the flow rate at unit i+1, m ³ /s.

In this exemplary embodiment, the flow rate of the throttle valve can be calculated by formula 6,

Formula 6 is:

where Q(j) is the flow at unit j, m ³ /s; Q(i) is the flow at unit i, m ³ /s; Q(i+1) is the flow at unit i+1, m ³ /s; O is the throttle valve opening coefficient.

In this exemplary embodiment, the opening degree of the throttle valve can be calculated by formula 7,

Formula 7 is:

Among them, τ(j) is the opening of the throttle valve; Q ₀ is the initial flow, m ³ /s; Q(in , _j ) is the flow at the unit j at the wellhead, m ³ /s; T _max is the throttle Valve limiting pressure time, s; Δt is the throttle valve adjustment interval, s; ζ is the throttle valve flow coefficient; H(in , _j ) is the wellhead pressure head, m.

To sum up, the beneficial effects of the present invention include at least one of the following:

(1) The present invention provides an automatic well kill simulation device for managed pressure drilling, which can simulate working conditions such as tripping, drilling, and overflow killing of wellbore multiphase flow in a controlled pressure environment;

(2) The present invention provides a method for precise control of back pressure by automatic well killing in managed pressure drilling, and a method for calculating the peak value of maximum fluctuating pressure in valve adjustment control;

(3) The present invention provides a method for precise control of back pressure by automatic killing of wells in managed pressure drilling, and provides a method for planned and staged control according to smooth curves in valve adjustment control;

(4) The present invention provides a method for precise control of back pressure by automatic well killing for managed pressure drilling, and the influence of fluctuating pressure is considered in the calculation model of back pressure in different working conditions of managed pressure drilling.

While the present invention has been described above with reference to the exemplary embodiments and accompanying drawings, it will be apparent to those skilled in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims (12)

1. An automatic kill simulation device for pressure-controlled drilling is characterized by comprising a casing, a drill rod, a wellhead casing pressure sensor, a riser pressure sensor, a bottom pressure sensor, a pressure sensor in a well, a gas-liquid flowmeter, a gas injection unit, a coiling unit, an industrial control unit and a throttle valve, wherein,

the casing is arranged in the simulated borehole, the drill rod is arranged in the casing, and the wellhead casing is arranged on the casing and is communicated with an annulus between the inner wall of the casing and the outer wall of the drill rod;

the wellhead casing pressure sensor can measure the pressure of the wellhead casing, the gas-liquid flowmeter can measure the flow of drilling fluid in the wellhead casing, and the throttle valve can open and close a wellhead of the wellhead casing;

the riser pressure sensor is capable of measuring the pressure of the drilling fluid in the drill pipe, the in-well pressure sensor is capable of measuring the pressure in the middle of the casing pipe, and the bottom-hole pressure sensor is capable of measuring the pressure at the bottom of the well;

the gas injection unit can inject gas into the annular space to simulate the overflow invasion of downhole gas;

the wire coiling unit can pull up and lower down the drill rod so as to simulate the process of pulling up and down;

the industrial control unit is respectively connected with the wellhead casing pressure sensor, the riser pressure sensor, the shaft bottom pressure sensor, the in-well pressure sensor, the gas injection unit, the coiling unit and the throttle valve so as to acquire pressure data tested by the wellhead casing pressure sensor, the riser pressure sensor, the shaft bottom pressure sensor and the in-well pressure sensor and control the gas injection unit, the coiling unit and the throttle valve.

2. The automatic kill simulation device of claim 1 further comprising a drilling fluid leakage unit disposed at a bottom of the simulated wellbore to simulate a drilling fluid leakage.

3. The automatic kill simulation device of claim 1 wherein the automatic kill simulation device further comprises a drilling fluid weighing unit capable of automatically weighing the amount of drilling fluid leaked out.

4. The automatic kill simulation device of claim 1 wherein the automatic kill simulation device further comprises a drill pump that pumps drilling fluid into the drill pipe.

5. A fine control back pressure method for automatic well killing of the pressure-controlled drilling, which is characterized in that the back pressure of the tripping working condition of the pressure-controlled drilling, the tripping working condition of the pressure-controlled drilling and/or the overflow and leakage killing working condition of the pressure-controlled drilling is controlled by the automatic well killing simulation device for the pressure-controlled drilling as claimed in any one of claims 1 to 4.

6. The method for controlling the back pressure of the automatic well killing fine control of the pressure control drilling according to claim 5, wherein the back pressure control of the pressure control drilling tripping working condition comprises the following steps:

the industrial control unit controls the wire winding unit to pull up the drill rod, and swabbing pressure generated in the drill pulling process is simulated;

gas is injected into the well bottom by controlling the gas injection unit through the industrial control unit, and a multiphase flow field in a shaft is simulated;

controlling the opening of the throttle valve through an industrial control unit, and simulating the wellhead back pressure of the pressure-controlled drilling well in the process of tripping;

the industrial control unit collects the swabbing pressure in the process of tripping in real time through a wellhead casing pressure sensor, a riser pressure sensor, a pressure sensor in the well and a pressure sensor at the bottom of the well;

the real-time back pressure of the pressure control well drilling tripping process is calculated by an equation 1,

formula 1 is:

p_b ^(t1)＝p_w ^(t1)-p_h ^(t1)-p_f ^(t1)+p_s ^(t1)+p_k ^(t1)

wherein p is_b ^(t1)The real-time back pressure is Mpa under the condition of tripping operation; p is a radical of_w ^(t1)The real-time bottom hole pressure is Mpa under the working condition of tripping; p is a radical of_h ^(t1)Real-time hydrostatic column pressure, Mpa, for tripping conditions; p is a radical of_f ^(t1)The real-time friction resistance is Mpa under the condition of tripping operation; p is a radical of_s ^(t1)Pumping pressure in real time under the condition of tripping operation, wherein the pumping pressure is Mpa; p is a radical of_k ^(t1)The fluctuation pressure, MPa, generated by the throttle valve under the condition of tripping-out is adjusted.

7. The method for controlling the back pressure of the automatic well killing fine control of the controlled pressure drilling according to claim 5, wherein the back pressure control of the drilling condition of the controlled pressure drilling comprises the following steps:

the industrial control unit controls the wire coiling unit to lower the drill rod, and exciting pressure generated in the drilling process is simulated;

gas is injected into the well bottom by controlling the gas injection unit through the industrial control unit, and a multiphase flow field in a shaft in the drilling process is simulated;

the opening of the throttle valve is controlled through the industrial control unit, and wellhead back pressure of the pressure-controlled drilling well in the drilling process is simulated;

the industrial control unit collects exciting pressure in the drilling process in real time through a wellhead casing pressure sensor, a riser pressure sensor, a well pressure sensor and a well bottom pressure sensor;

the real-time back pressure of the drilling working condition of the controlled pressure drilling is calculated by the formula 2,

the formula 2 is:

p_b ^(t2)＝p_w ^(t2)-p_h ^(t2)-p_f ^(t2)-p_g ^(t2)+p_k ^(t2)

wherein p is_b ^(t2)The pressure is real-time back pressure under the working condition of drilling; p is a radical of_w ^(t2)Real-time bottom hole pressure under Mpa for the downhole condition; p is a radical of_h ^(t2)Real-time hydrostatic column pressure, Mpa, for the downhole condition; p is a radical of_f ^(t2)The real-time friction resistance is Mpa under the drilling working condition; p is a radical of_g ^(t2)Stimulating pressure in real time for the working condition of drilling down, Mpa; p is a radical of_k ^(t2)The fluctuation pressure, MPa, generated by the throttle valve under the drilling condition is adjusted.

8. The method for controlling the back pressure of the automatic well killing fine control of the managed pressure drilling according to claim 5, wherein the back pressure control of the overflow well killing condition of the managed pressure drilling comprises the following steps:

gas is injected into the well bottom by controlling the gas injection unit through the industrial control unit, and a multiphase flow field in a shaft in the overflow invasion process is simulated;

the opening of the throttle valve is controlled through an industrial control unit, and the throttle circulation open flow of the pressure control drilling well in the process of overflow and kill well is simulated;

the overflow leakage unit is opened through the industrial control unit, the leakage of the drilling fluid in the overflow well killing process is simulated, and the leakage quantity of the drilling fluid is obtained;

the opening of the throttle valve is controlled through the industrial control unit, and wellhead back pressure of the pressure-controlled drilling well in the overflow leakage invasion process is simulated;

the industrial control unit collects the gas slippage pressure drop in the process of overflow leakage and well killing in real time through a wellhead casing pressure sensor, a riser pressure sensor, a pressure sensor in the well and a pressure sensor at the bottom of the well;

the real-time back pressure of the working condition of the pressure-controlled drilling, overflow and leakage killing well is calculated by the formula 3,

formula 3 is:

p_b ^(t3)＝p_w ^(t3)-p_h ^(t3)-p_f ^(t3)-p_m ^(t3)+p_k ^(t3)

wherein p is_b ^(t3)The pressure is the real-time return pressure of the working condition of the overflow and leakage killing well, and is Mpa; p is a radical of_w ^(t3)The real-time bottom hole pressure is Mpa under the working condition of overflow and leakage killing; p is a radical of_h ^(t3)The real-time hydrostatic column pressure is Mpa under the working condition of the overflow drain killing well; p is a radical of_f ^(t3)The real-time friction resistance is Mpa under the working condition of the overflow and leakage killing well; p is a radical of_m ^(t3)The pressure drop is the real-time gas slippage pressure drop under the working condition of the overflow and leakage killing well, and is Mpa; p is a radical of_k ^(t3)The fluctuating pressure, MPa, produced for throttle valve regulation.

9. The method of claim 6, 7 or 8, wherein the real-time frictional resistance of the tripping condition, the tripping condition and the overflow and kill condition is calculated by equation 4,

formula 4 is:

h_f＝λlu²/2d

wherein h is_fThe real-time friction resistance is Mpa under the working conditions of tripping, running and overflow and leakage killing; λ is the coefficient of frictional resistance; l represents the cannula length, m; u represents the velocity, m/s.

10. The method of claim 6, 7 or 8, wherein the fluctuating pressures generated by the tripping, tripping and flooding condition choke adjustments are calculated by equation 5,

formula 5 is:

c⁺:H_i+1＝H_i-B(Q_i+1-Q_i)-RQ_i|Q_i| (5-1)

c^-:H_i＝H_i+1-B(Q_i-Q_i+1)+RQ_i+1|Q_i+1| (5-2)

wherein B is a transfer parameter value c/(g.A); r is a transfer parameter value; c. C⁺：H_i+1Represents the fluctuating pressure in the v + c direction, MPa; c. C^-：H_iRepresents the fluctuating pressure in the v-c direction, MPa; q (i) is the flow at unit i, m³S; q (i +1) is the flow at the i +1 cell, m³/s。

11. The method of claim 10, wherein the choke flow is calculated by equation 6,

formula 6 is:

where Q (j) is the flow at unit j, m³S; q (i) is the flow at unit i, m³S; q (i +1) is the flow at the i +1 cell, m³S; and O is a throttle opening coefficient.

12. The method of claim 11, wherein the opening of the throttle valve is calculated by equation 7,

formula 7 is:

wherein τ (j) is the opening of the throttle valve; q₀Is an initial flow rate, m³/s；Q(i_nJ) flow at wellhead j unit, m³/s；T_maxLimiting the pressure time for the throttle valve, s; delta t is a throttle valve adjustment interval, s; zeta is the flow coefficient of the throttle valve; h (i)_nAnd j) is the wellhead pressure head, m.

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