Monitoring Method and Equipment for Bottom-Hole Formation Pressure, Killing Method and System

Abstract

The present invention discloses a method and device for monitoring bottom-hole formation pressure, a well killing method and system. The method includes: obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is seated after well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string hanging weight before and after the downhole blowout preventer is seated; substituting the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change amount of the well string hanging weight into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure, realizing the rapid monitoring of the bottom-hole formation pressure by using the change of the pipe string hanging weight before and after the packer is seated, so as to determine a suitable well killing fluid density and then perform well killing based on the suitable well killing fluid density, thereby being able to improve the efficiency of handling accidents such as well kick or overflow.

Description

Technical Field

[0001] The present invention belongs to the technical field of drilling engineering, and particularly relates to a method and device for monitoring bottom-hole formation pressure, a well killing method and system. Background Art

[0002] During the drilling process of deep wells and high-pressure wells, the risks of overflow and blowout are high. Traditional wellhead blowout preventers have defects such as lagging response in closing the well and killing the well, complex operation, and long operation cycle, posing a severe challenge to well control safety.

[0003] The downhole blowout preventer is a downhole well control tool used in the drilling process. The downhole blowout preventer is lowered into the wellbore along with the drill string. After an overflow signal is detected on the ground, the well is closed through the wellhead blowout preventer, and then the downhole blowout preventer is activated to set it, isolating the high-pressure formation and fluid downhole. Subsequently, a circulation channel is established and well killing conditions are provided. By injecting heavy mud in circulation to balance the bottom-hole formation pressure, after the well killing operation is completed, the downhole blowout preventer is released and the drilling or tripping operation continues. The downhole blowout preventer can, to a certain extent, isolate the high-pressure formation in the wellbore, reduce the wellhead pressure, reduce the difficulty of well killing, and shorten the well killing cycle, so as to achieve the purpose of reducing well control risks.

[0004] The existing conventional wellhead blowout preventer group well killing technology mainly obtains the bottom-hole pore pressure by reading the data of the surface casing pressure and drill pipe pressure gauges when closing the well, so as to determine the appropriate density of the well killing fluid.

[0005] However, since the setting of the downhole blowout preventer will seal off the annulus, resulting in the separation of the liquid columns above and below the downhole blowout preventer and the inability to establish a full-wellbore circulation in a timely manner, the conventional well killing calculation method cannot accurately obtain the bottom-hole formation pressure parameters. Summary of the Invention

[0006] The main object of the present invention is to provide a method and device for monitoring bottom-hole formation pressure, a well killing method and system, so as to solve the problem that the existing method cannot accurately monitor the bottom-hole formation pressure when the downhole blowout preventer is set.

[0007] In view of the above problems, the present invention provides a method for monitoring bottom-hole formation pressure, including:

[0008] Obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer completes setting after closing the well, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string hook load before and after the downhole blowout preventer is set;

[0009] Substituting the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change amount of the pipe string hook load into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure.

[0010] Further, in the above-described method for monitoring the bottom-hole formation pressure, the internal pressure of the downhole blowout preventer is determined according to the following steps:

[0011] Obtain the standpipe pressure when the downhole blowout preventer is set;

[0012] Determine the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0013] Further, in the above-described method for monitoring the bottom-hole formation pressure, determining the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer includes:

[0014] Substitute the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer;

[0015] Wherein, the internal pressure calculation formula is:

[0016] P 压 = P 立 + ρgh 循 ; P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the standpipe pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0017] Further, in the above-described method for monitoring the bottom-hole formation pressure, the pressure of the circulation hole of the downhole blowout preventer is determined according to the following steps:

[0018] Obtain the casing head pressure before closing the well;

[0019] Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0020] Further, in the above-described method for monitoring the bottom-hole formation pressure, determining the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer includes:

[0021] Substitute the casing head pressure before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer;

[0022] Wherein, the circulation hole pressure calculation formula is:

[0023] P 上 = P 套 + ρgh循 ; P 上 represents the pressure of the circulating hole of the downhole blowout preventer, P 套 represents the casing pressure at the wellhead before closing the well, h 循 represents the distance from the top drive to the circulating hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0024] Furthermore, in the above-mentioned method for monitoring the bottom-hole formation pressure, the calculation formula for the bottom-hole formation pressure is:

[0025]

[0026] wherein, P 底 represents the bottom-hole formation pressure, P 压 represents the internal pressure of the downhole blowout preventer, P 上 represents the pressure of the circulating hole of the downhole blowout preventer, ΔT represents the change in the hook load before and after the downhole blowout preventer is set, h 封 represents the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom of the well, h 内 represents the vertical distance from the inner blowout preventer tool closest to the bit to the bottom of the well, H represents the vertical distance from the circulating hole to the inner blowout preventer tool closest to the bit, S 环 represents the annular cross-sectional area at the location of the downhole blowout preventer, S 内 represents the internal cross-sectional area at the inner blowout preventer tool, L represents the length of the rubber barrel of the downhole blowout preventer, D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0027] The present invention also provides a well killing method, including:

[0028] If a well closing operation is monitored, according to the above-mentioned method for monitoring the bottom-hole formation pressure, determine the bottom-hole formation pressure;

[0029] According to the bottom-hole formation pressure, determine the density of the well killing fluid;

[0030] Release the downhole blowout preventer, and perform circulating well killing based on the density of the well killing fluid until the casing pressure at the wellhead meets the preset end condition, and then stop the well killing.

[0031] Furthermore, in the above-mentioned well killing method, determining the density of the well killing fluid according to the bottom-hole formation pressure includes:

[0032] Substitute the bottom-hole formation pressure into the preset calculation formula for the density of the well killing fluid for calculation to obtain the density of the well killing fluid;

[0033] wherein, the calculation formula for the density of the well killing fluid is:

[0034] ρ 压Denotes the kill fluid density, P 底 Denotes the bottom hole formation pressure, H V Denotes the vertical depth of the well, ρ 附 Denotes the additional kill fluid density required based on the well conditions.

[0035] The present invention also provides a monitoring device for bottom hole formation pressure, comprising a memory and a controller;

[0036] A computer program is stored on the memory, and when the computer program is executed by the controller, the steps of the monitoring method for bottom hole formation pressure as described above are realized.

[0037] The present invention also provides a kill well system, comprising a kill well device and the monitoring device for bottom hole formation pressure as described above;

[0038] The monitoring device for bottom hole formation pressure is used to realize the steps of the monitoring method for bottom hole formation pressure as described above when executed;

[0039] The kill well device is used to determine the kill fluid density according to the bottom hole formation pressure monitored by the monitoring device for bottom hole formation pressure; release the downhole blowout preventer, and perform circulating kill based on the kill fluid density until the casing pressure at the wellhead meets the preset end condition, and then stop the kill well operation.

[0040] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0041] The monitoring method and device for bottom hole formation pressure, kill well method and system of the present invention obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is seated after closing the well, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string suspension weight before and after the downhole blowout preventer is seated, and substitute the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer and the change amount of the well string suspension weight into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure, realizing the rapid monitoring of the bottom hole formation pressure by using the change of the pipe string suspension weight before and after the packer is seated, so as to determine a suitable kill fluid density and then perform kill well based on the suitable kill fluid density, thereby being able to improve the efficiency of dealing with accidents such as well kick or overflow.

[0042] Other features and advantages of the present invention will be described in the following specification, and will be partially obvious from the specification, or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures specifically pointed out in the specification, claims and drawings. Description of the Drawings

[0043] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0044] Figure 1 is a flowchart of an embodiment of the method for monitoring the bottom-hole formation pressure of the present invention;

[0045] Figure 2 is a schematic diagram of the state when the downhole blowout preventer is set;

[0046] Figure 3 is a flowchart of an embodiment of the well killing method of the present invention;

[0047] Figure 4 is a schematic structural diagram of an embodiment of the device for monitoring the bottom-hole formation pressure of the present invention;

[0048] Figure 5 is a schematic structural diagram of an embodiment of the well killing device of the present invention;

[0049] Figure 6 is a schematic structural diagram of an embodiment of the equipment for monitoring the bottom-hole formation pressure of the present invention;

[0050] Figure 7 is a schematic structural diagram of an embodiment of the well killing system of the present invention. Detailed Embodiments

[0051] The following will describe in detail the embodiments of the present invention in conjunction with the accompanying drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0052] Embodiment 1

[0053] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a method for monitoring the bottom-hole formation pressure.

[0054] Figure 1 is a flowchart of an embodiment of the method for monitoring the bottom-hole formation pressure of the present invention. As Figure 1 shown, the method for monitoring the bottom-hole formation pressure in this embodiment may specifically include the following steps:

[0055] 100. Obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is set after shutting in the well, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set;

[0056] In a specific implementation process, the internal pressure of the downhole blowout preventer can be determined according to the following steps:

[0057] a. Obtain the riser pressure when the downhole blowout preventer is set;

[0058] Figure 2 is a schematic diagram of the state when the downhole blowout preventer is set, Figure 2 in which, 1 is the standpipe pressure gauge, 2 is the casing pressure gauge, 3 is the circulation hole, 4 is the rubber barrel, 5 is the internal blowout preventer tool, 6 is the drill bit, and 7 is the bottom of the well.

[0059] In this embodiment, the downhole blowout preventer is lowered into the well along with the drill string for normal drilling. If during the drilling process, overflow or blowout risks are detected, the wellhead blowout preventer can be quickly closed, and data such as the flow rate, pipe string hook load, drilling fluid density, pump pressure, wellhead casing pressure, and riser pressure at this time can be recorded. At the same time, the downhole blowout preventer is activated by mechanical pressing or ball dropping, and the pump is operated to build pressure to set the rubber barrel 4 of the downhole blowout preventer, and the monitored riser pressure is obtained when the downhole blowout preventer is set.

[0060] b. Determine the internal pressure of the downhole blowout preventer according to the riser pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0061] In this embodiment, after obtaining the riser pressure, the riser pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer can be substituted into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer.

[0062] Specifically, the preset internal pressure calculation formula in this embodiment is as shown in calculation formula (1):

[0063] P 压 = P 立 + ρgh 循 (1)

[0064] where, P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the riser pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the drilling fluid density, and g represents the acceleration due to gravity.

[0065] In a specific implementation process, the pressure of the circulation hole of the downhole blowout preventer is determined according to the following steps:

[0066] a1. Obtain the wellhead casing pressure before closing the well;

[0067] In this embodiment, the monitored wellhead casing pressure before closing the well can be obtained.

[0068] b1. Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0069] In this embodiment, after the rubber barrel 4 of the downhole blowout preventer is set, continue to build pressure until the differential pressure sliding sleeve opens the circulation hole, and realize circulation above the rubber barrel 4 (equivalent to establishing a complete circulation above the downhole blowout preventer), discharge the invaded fluid in the drilling fluid, so that the casing head pressure measured by the casing pressure gauge 2 is 0, and determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0070] Specifically, the pressure of the circulation hole of the downhole blowout preventer can be obtained by substituting the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset circulation hole pressure calculation formula for calculation.

[0071] The circulation hole pressure calculation formula in this embodiment is as shown in calculation formula (2):

[0072] P 上 =P 套 +ρgh 循 (2)

[0073] Wherein, P 上 represents the pressure of the circulation hole of the downhole blowout preventer, P 套 represents the casing head pressure before well shut-in, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration of gravity.

[0074] In practical applications, the process of obtaining the change amount of the pipe string suspended weight before and after the downhole blowout preventer is set is as follows:

[0075] After the pipe string suspended weight is stable, record the casing suspended weight at this time, and take the difference from the casing suspended weight monitored before well shut-in to obtain the change amount of the pipe string suspended weight before and after the downhole blowout preventer is set.

[0076] 101. Substitute the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change amount of the well string suspended weight into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure.

[0077] In a specific implementation process, based on the mechanical equilibrium equation of the pipe string, the following corresponding relationship between the change in suspended weight and the change in pressure can be established, such as calculation formula (3):

[0078]

[0079] Solving the calculation formula can obtain the bottom hole formation pressure calculation formula as shown in calculation formula (4):

[0080]

[0081] Among them, P 底 represents the bottom-hole formation pressure, and P 压 represents the internal pressure of the downhole blowout preventer, and P 上 represents the pressure of the circulation hole of the downhole blowout preventer. ΔT represents the change in hook load before and after the downhole blowout preventer is set, and h 封 represents the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom hole, and h 内 represents the vertical distance from the innermost blowout preventer tool closest to the bit to the bottom hole. H represents the vertical distance from the circulation hole to the innermost blowout preventer tool closest to the bit, and S 环 represents the annular cross-sectional area at the position where the downhole blowout preventer is located, and S 内 represents the internal cross-sectional area at the innermost blowout preventer tool. L represents the length of the rubber barrel of the downhole blowout preventer. D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer. ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0082] In this embodiment, after obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is completely set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the pipe string hook load before and after the downhole blowout preventer is set, the internal pressure of the downhole blowout preventer when the downhole blowout preventer is completely set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the pipe string hook load before and after the downhole blowout preventer is set can be substituted into the pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure.

[0083] The method for monitoring the bottom-hole formation pressure in this embodiment realizes the rapid monitoring of the bottom-hole formation pressure by using the change in the pipe string hook load before and after the packer is set. After obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is completely set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the pipe string hook load before and after the downhole blowout preventer is set, and substituting the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the pipe string hook load into the pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure. After determining the appropriate kill fluid density, kill well based on the appropriate kill fluid density, which can improve the efficiency of dealing with accidents such as well kick or overflow.

[0084] Embodiment 2

[0085] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a kill well method.

[0086] Figure 3 For the flowchart of the kill well method embodiment of the present invention, as Figure 3 shown, the kill well method in this embodiment may specifically include the following steps:

[0087] 300. If a well shut-in operation is monitored, obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is fully set after the well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the pipe string hook load before and after the downhole blowout preventer is set.

[0088] In a specific implementation process, the internal pressure of the downhole blowout preventer is determined according to the following steps:

[0089] a. Obtain the standpipe pressure when the downhole blowout preventer is fully set.

[0090] b. Determine the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0091] In this embodiment, after obtaining the standpipe pressure, the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer can be substituted into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer. Among them, the preset internal pressure calculation formula in this embodiment is as shown in formula (1).

[0092] In a specific implementation process, the pressure of the circulation hole of the downhole blowout preventer is determined according to the following steps:

[0093] a1. Obtain the casing head pressure before the well shut-in.

[0094] In this embodiment, the monitored casing head pressure before the well shut-in can be obtained.

[0095] b1. Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before the well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0096] In this embodiment, after the rubber barrel 4 of the downhole blowout preventer is fully set, continue to build up pressure until the differential pressure sliding sleeve opens the circulation hole, and realize circulation above the rubber barrel 4 (equivalent to establishing a complete circulation above the downhole blowout preventer), discharge the invaded fluid in the drilling fluid, so that the casing head pressure measured by the casing pressure gauge 2 is 0, and determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before the well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0097] Specifically, the casing head pressure before the well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer can be substituted into a preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer. Among them, the circulation hole pressure calculation formula in this embodiment is as shown in formula (2).

[0098] In practical applications, the process of obtaining the change in the pipe string hook load before and after the downhole blowout preventer is set is as follows:

[0099] After the string hanging weight is stabilized, record the casing hanging weight at this time, and take the difference from the casing hanging weight monitored before closing the well to obtain the change in the string hanging weight before and after the downhole blowout preventer is set.

[0100] 301. Substitute the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the string hanging weight into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure.

[0101] In a specific implementation process, based on the mechanical equilibrium equation of the string, the following corresponding relationship between the change in hanging weight and the change in pressure can be established, such as calculation formula (3). In this way, after obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is fully set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set, the internal pressure of the downhole blowout preventer when the downhole blowout preventer is fully set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set can be substituted into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure.

[0102] 302. Determine the kill fluid density according to the bottom-hole formation pressure.

[0103] In a specific implementation process, the bottom-hole formation pressure can be substituted into a preset kill fluid density calculation formula for calculation to obtain the kill fluid density.

[0104] Among them, the kill fluid density calculation formula is:

[0105] ρ 压 represents the kill fluid density, P 底 represents the bottom-hole formation pressure, H V represents the vertical depth of the well, ρ 附 represents the additional kill fluid density required based on the well conditions.

[0106] 303. Release the downhole blowout preventer, and perform circulating kill based on the kill fluid density until the casing pressure at the wellhead meets the preset end condition, and then stop the kill operation.

[0107] In this embodiment, after determining the kill fluid density, prepare the corresponding kill fluid according to the determined kill fluid density, and slowly lift the string to release the downhole blowout preventer. At this time, continuously pump in the kill fluid, and the kill fluid enters the inside of the drill pipe through the pipeline, flows through the internal blowout preventer tool 5, the drill bit 6, and the bottom hole 7, and returns to the ground from the annulus until the pressure on the casing pressure gauge becomes 0, and the kill process ends. Among them, the annulus is the gap between the string and the wellbore wall, and the internal blowout preventer tool 5 is preferably a check valve.

[0108] The well killing method of this embodiment obtains the internal pressure of the downhole blowout preventer when the downhole blowout preventer is seated after well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the pipe string suspended weight before and after the downhole blowout preventer is seated. Then, substituting the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the pipe string suspended weight into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure. It realizes the rapid monitoring of the bottom hole formation pressure by using the change in the pipe string suspended weight before and after the packer is seated. After determining the appropriate well killing fluid density, well killing is carried out based on the appropriate well killing fluid density until the wellhead casing pressure meets the preset end condition, and then the well killing is stopped. Furthermore, it can improve the efficiency of handling accidents such as well kick or overflow.

[0109] It should be noted that the method of this embodiment of the present invention can be executed by a single device, such as a computer or a server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In this case of a distributed scenario, one of the multiple devices can only execute one or more steps of the method of this embodiment of the present invention, and these multiple devices will interact with each other to complete the method.

[0110] Embodiment III

[0111] The method for monitoring the bottom hole formation pressure and the well killing method of this embodiment can be used in the working conditions where a downhole blowout preventer assembly is used during the oil and gas drilling process.

[0112] First step: Lower the downhole blowout preventer and drill normally.

[0113] Second step: When an overflow is detected, quickly close the wellhead blowout preventer and record the suspended weight at this time. At the same time, start the downhole blowout preventer by mechanical pressing or ball dropping, open the pump to build pressure, and make the rubber barrel 4 of the downhole blowout preventer seat.

[0114] Third step: Continue to build pressure until the differential pressure sliding sleeve opening pressure is reached, open the circulation hole, achieve circulation above the rubber barrel 4, discharge the invaded fluid in the drilling fluid, and make the wellhead casing pressure 2 equal to 0.

[0115] Fourth step: After the pipe string suspended weight is stable, record the casing suspended weight at this time.

[0116] Fifth step: Determine the bottom hole formation pressure according to the method for monitoring the bottom hole formation pressure in Embodiment I, and determine the well killing fluid density based on the bottom hole formation pressure, and prepare the well killing fluid.

[0117] Sixth step: Slowly lift the pipe string to release the rubber barrel 4. At this time, continuously pump in the well killing fluid. The well killing fluid enters the inside of the drill pipe through the pipeline, flows through the internal blowout preventer tool 5, the drill bit 6, the bottom hole 7, and returns to the ground through the annulus.

[0118] Step 7: Drain the aftereffect. Wait until the pressure on the casing pressure gauge becomes 0, and the well killing process ends.

[0119] In this embodiment, when a kick occurs during the drilling process and both the surface blowout preventer and the downhole blowout preventer are activated simultaneously, a method for obtaining the bottom hole formation pressure by using the change in the drill string suspension weight is provided. This method is proposed for the first time for this special working condition when the downhole blowout preventer is working, and can effectively guide the application of the blowout preventer on site and obtain the bottom hole formation pressure in a timely manner, so as to quickly determine the density of the well killing fluid. This invention can save the time for determining the density of the well killing fluid when the downhole blowout preventer is working, and thus quickly and effectively handle accidents such as well kick or overflow.

[0120] Embodiment 4

[0121] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a monitoring device for the bottom hole formation pressure.

[0122] Figure 4 As shown in the structural schematic diagram of the embodiment of the monitoring device for the bottom hole formation pressure of the present invention, Figure 4 the monitoring device for the bottom hole formation pressure of this embodiment may include an acquisition module 40 and a calculation module 41.

[0123] The acquisition module 40 is used to acquire the internal pressure of the downhole blowout preventer when the downhole blowout preventer is fully seated after closing the well, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string suspension weight before and after the downhole blowout preventer is seated.

[0124] In a specific implementation process, the internal pressure of the downhole blowout preventer is determined according to the following steps:

[0125] a. Acquire the standpipe pressure when the downhole blowout preventer is fully seated.

[0126] b. Determine the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0127] In this embodiment, after the standpipe pressure is acquired, the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer can be substituted into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer. Among them, the preset internal pressure calculation formula in this embodiment is as shown in calculation formula (1).

[0128] In a specific implementation process, the pressure of the circulation hole of the downhole blowout preventer is determined according to the following steps:

[0129] a1. Acquire the casing pressure at the wellhead before closing the well.

[0130] In this embodiment, the monitored casing pressure at the wellhead before closing the well can be acquired.

[0131] b1. Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0132] In this embodiment, after the rubber barrel 4 of the downhole blowout preventer is set, continue to build pressure until the differential pressure sliding sleeve opens the circulation hole, and realize circulation above the rubber barrel 4 (equivalent to establishing a complete circulation above the downhole blowout preventer), discharge the invaded fluid in the drilling fluid, so that the casing head pressure measured by the casing pressure gauge 2 is 0, and determine the pressure of the circulation hole of the downhole blowout preventer according to the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0133] Specifically, the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer can be substituted into a preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer. Among them, the circulation hole pressure calculation formula in this embodiment is as shown in formula (2).

[0134] In practical applications, the process of obtaining the change amount of the pipe string hook load before and after the downhole blowout preventer is set is as follows:

[0135] After the pipe string hook load is stable, record the casing hook load at this time, and subtract the casing hook load monitored before well shut-in to obtain the change amount of the pipe string hook load before and after the downhole blowout preventer is set.

[0136] The calculation module 41 is used to substitute the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change amount of the pipe string hook load into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure.

[0137] In a specific implementation process, based on the mechanical equilibrium equation of the pipe string, the following corresponding relationship between the hook load change and the pressure change can be established, as shown in formula (3). In this way, after obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is completely set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string hook load before and after the downhole blowout preventer is set, the internal pressure of the downhole blowout preventer when the downhole blowout preventer is completely set, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string hook load before and after the downhole blowout preventer is set can be substituted into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure.

[0138] The bottom-hole formation pressure monitoring device of this embodiment obtains the internal pressure of the downhole blowout preventer when the downhole blowout preventer is set after well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set. Then, the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the string hanging weight are substituted into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure. By using the change in the string hanging weight before and after the packer is set, the bottom-hole formation pressure can be quickly monitored, so that after determining the appropriate kill fluid density, kill well is carried out based on the appropriate kill fluid density, thereby improving the efficiency of handling accidents such as well kicks or overflows.

[0139] The device of the above embodiment is used to implement the corresponding method in the foregoing embodiment. The specific implementation solution can refer to the method described in the foregoing embodiment and the relevant descriptions in the method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be elaborated here.

[0140] Embodiment Five

[0141] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a kill well device.

[0142] Figure 5 For the structural schematic diagram of the kill well device embodiment of the present invention, as Figure 5 shown, this embodiment includes a determination module 50 and a kill well module 51.

[0143] The determination module 50 is configured to, if a well shut-in operation is monitored, determine the bottom-hole formation pressure according to the bottom-hole formation pressure monitoring method of the above embodiment, and determine the kill fluid density according to the bottom-hole formation pressure;

[0144] Specifically, the bottom-hole formation pressure can be substituted into a preset kill fluid density calculation formula for calculation to obtain the kill fluid density;

[0145] Among them, the kill fluid density calculation formula is:

[0146] ρ 压 represents the kill fluid density, P 底 represents the bottom-hole formation pressure, H V represents the vertical depth of the well, ρ 附 represents the additional kill fluid density required based on the well conditions.

[0147] The kill well module 51 is configured to release the downhole blowout preventer and perform circulating kill well based on the kill fluid density until the casing pressure at the wellhead meets a preset end condition, and then stop kill well.

[0148] The kill well device of this embodiment obtains the internal pressure of the downhole blowout preventer when the downhole blowout preventer is set after well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set. Then, the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the string hanging weight are substituted into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure. By using the change in the string hanging weight before and after the packer is set, the bottom hole formation pressure can be quickly monitored. After determining the appropriate kill fluid density, kill well is carried out based on the appropriate kill fluid density until the casing pressure at the wellhead meets the preset end condition, and then the kill well is stopped. By adopting the technical solution of the present invention, the efficiency of dealing with accidents such as well kick or overflow can be improved.

[0149] The device of the above embodiment is used to implement the corresponding method in the foregoing embodiment. The specific implementation solution can refer to the method described in the foregoing embodiment and the relevant description in the method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be elaborated here.

[0150] Embodiment Six

[0151] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a monitoring device for bottom hole formation pressure.

[0152] Figure 6 As shown in the structural schematic diagram of the embodiment of the monitoring device for the bottom hole formation pressure of the present invention, Figure 6 as shown, the device may include: a processor 1010 and a memory 1020. As known to those skilled in the art, the device may further include an input / output interface 1030, a communication interface 1040, and a bus 1050. Among them, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other inside the device through the bus 1050.

[0153] The processor 1010 may be implemented in a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0154] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage devices, dynamic storage devices, etc. The memory 1020 can store the operating system and other application programs. When implementing the technical solutions provided in the embodiments of this specification through software or firmware, the relevant program codes are stored in the memory 1020 and called and executed by the processor 1010.

[0155] The input / output interface 1030 is used to connect to the input / output module to realize information input and output. The input / output module can be configured as a component in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Among them, the input device can include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device can include a display, a speaker, a vibrator, an indicator light, etc.

[0156] The communication interface 1040 is used to connect to the communication module (not shown in the figure) to realize the communication interaction between this device and other devices. Among them, the communication module can realize communication through wired means (such as USB, network cable, etc.) or through wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0157] The bus 1050 includes a path for transmitting information between various components of the device (such as the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0158] It should be noted that although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050, in the specific implementation process, this device may also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device may also only include the components necessary to implement the solutions of the embodiments of this specification, and do not have to include all the components shown in the figure.

[0159] In a specific implementation process, a computer program is stored on the memory in the monitoring device for the bottom-hole formation pressure provided in this embodiment. When the computer program is executed by the processor, the following steps are implemented:

[0160] Obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is seated after the well is shut in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is seated;

[0161] Substitute the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the suspended weight of the well string into the pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure.

[0162] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0163] Obtain the standpipe pressure when the downhole blowout preventer is set;

[0164] Determine the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0165] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0166] Substitute the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer into the preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer;

[0167] Among them, the internal pressure calculation formula is:

[0168] P 压 =P 立 +ρgh 循 ; P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the standpipe pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration of gravity.

[0169] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0170] Obtain the casing pressure at the wellhead before closing the well;

[0171] Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing pressure at the wellhead before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0172] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0173] Substitute the casing pressure at the wellhead before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer into the preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer;

[0174] Among them, the circulation hole pressure calculation formula is:

[0175] P 上 =P 套 +ρgh 循 ; P上 Indicates the pressure of the circulating hole of the downhole blowout preventer, P 套 Indicates the casing pressure at the wellhead before closing the well, h 循 Indicates the distance from the top drive to the circulating hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0176] Furthermore, the calculation formula for the bottom hole formation pressure is:

[0177]

[0178] Among them, P 底 Indicates the bottom hole formation pressure, P 压 Indicates the internal pressure of the downhole blowout preventer, P 上 Indicates the pressure of the circulating hole of the downhole blowout preventer, ΔT represents the change in hook load before and after the downhole blowout preventer is set, h 封 Indicates the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom of the well, h 内 Indicates the vertical distance from the inner blowout preventer tool closest to the bit to the bottom of the well, H represents the vertical distance from the circulating hole to the inner blowout preventer tool closest to the bit, S 环 Indicates the annular cross-sectional area at the location of the downhole blowout preventer, S 内 Indicates the inner cross-sectional area at the inner blowout preventer tool, L represents the length of the rubber barrel of the downhole blowout preventer, D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0179] Embodiment Seven

[0180] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a kill well system.

[0181] Figure 7 For the structural schematic diagram of the kill well system embodiment of the present invention, as Figure 7 shown, the kill well system of this embodiment includes a kill well device 70 and a monitoring device 71 for the bottom hole formation pressure.

[0182] In a specific implementation process, the monitoring device 70 for the bottom hole formation pressure includes a memory and a controller. A computer program is stored on the memory, and when the computer program is executed by a processor, the following steps are implemented:

[0183] Obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is set after closing the well, the pressure of the circulating hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change amount of the pipe string hook load before and after the downhole blowout preventer is set;

[0184] Substitute the internal pressure of the downhole blowout preventer, the pressure of the circulating hole of the downhole blowout preventer, and the change amount of the well string hook load into a pre-constructed bottom hole formation pressure calculation formula for calculation to obtain the bottom hole formation pressure.

[0185] Further, when the computer program is executed by a processor, the following steps can also be implemented:

[0186] Obtain the riser pressure when the downhole blowout preventer is set;

[0187] Determine the internal pressure of the downhole blowout preventer according to the riser pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0188] Further, when the computer program is executed by a processor, the following steps can also be implemented:

[0189] Substitute the riser pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer;

[0190] Wherein, the internal pressure calculation formula is:

[0191] P 压 = P 立 + ρgh 循 ; P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the riser pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0192] Further, when the computer program is executed by a processor, the following steps can also be implemented:

[0193] Obtain the casing pressure at the wellhead before closing the well;

[0194] Determine the pressure of the circulation hole of the downhole blowout preventer according to the casing pressure at the wellhead before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0195] Further, when the computer program is executed by a processor, the following steps can also be implemented:

[0196] Substitute the casing pressure at the wellhead before closing the well and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer;

[0197] Wherein, the circulation hole pressure calculation formula is:

[0198] P 上 = P 套 + ρgh 循 ; P 上 represents the pressure of the circulation hole of the downhole blowout preventer, P 套 represents the casing pressure at the wellhead before closing the well, h 循It represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0199] Furthermore, the calculation formula for the bottom hole formation pressure is:

[0200]

[0201] Among them, P 底 represents the bottom hole formation pressure, P 压 represents the internal pressure of the downhole blowout preventer, P 上 represents the pressure at the circulation hole of the downhole blowout preventer, ΔT represents the change in hook load before and after the downhole blowout preventer is set, h 封 represents the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom hole, h 内 represents the vertical distance from the innermost blowout preventer tool closest to the bit to the bottom hole, H represents the vertical distance from the circulation hole to the innermost blowout preventer tool closest to the bit, S 环 represents the annular cross-sectional area at the location of the downhole blowout preventer, S 内 represents the internal cross-sectional area at the innermost blowout preventer tool, L represents the length of the rubber barrel of the downhole blowout preventer, D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0202] The kill equipment 71 is used to determine the density of the kill fluid according to the bottom hole formation pressure; release the downhole blowout preventer, and perform circulating kill based on the density of the kill fluid until the casing pressure at the wellhead meets the preset end condition, and then stop the kill.

[0203] Specifically, substitute the bottom hole formation pressure into the preset calculation formula for the density of the kill fluid for calculation to obtain the density of the kill fluid;

[0204] Among them, the calculation formula for the density of the kill fluid is:

[0205] ρ 压 represents the density of the kill fluid, P 底 represents the bottom hole formation pressure, H V represents the vertical depth of the well, ρ 附 represents the additional density of the kill fluid required based on the well conditions.

[0206] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a storage medium.

[0207] The storage medium of this embodiment stores a computer program, and when the computer program is executed by a controller, the following steps are implemented:

[0208] Obtain the internal pressure of the downhole blowout preventer when the downhole blowout preventer is fully set after well shut-in, the pressure at the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set.

[0209] Substitute the internal pressure of the downhole blowout preventer, the pressure at the circulation hole of the downhole blowout preventer, and the change in the string hanging weight into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure.

[0210] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0211] Obtain the standpipe pressure when the downhole blowout preventer is fully set.

[0212] Determine the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0213] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0214] Substitute the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer;

[0215] Among them, the internal pressure calculation formula is:

[0216] P 压 =P 立 +ρgh 循 ;P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the standpipe pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0217] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0218] Obtain the casing head pressure before well shut-in;

[0219] Determine the pressure at the circulation hole of the downhole blowout preventer according to the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer.

[0220] Further, when the computer program is executed by the processor, the following steps can also be implemented:

[0221] Substitute the casing head pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset circulation hole pressure calculation formula for calculation to obtain the pressure at the circulation hole of the downhole blowout preventer;

[0222] Among them, the calculation formula for the pressure of the circulation hole is as follows:

[0223] P 上 = P 套 + ρgh 循 ; P 上 represents the pressure of the circulation hole of the downhole blowout preventer, P 套 represents the casing pressure at the wellhead before closing the well, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0224] Furthermore, the calculation formula for the bottom-hole formation pressure is as follows:

[0225]

[0226] Among them, P 底 represents the bottom-hole formation pressure, P 压 represents the internal pressure of the downhole blowout preventer, P 上 represents the pressure of the circulation hole of the downhole blowout preventer, ΔT represents the change in the hook load before and after the downhole blowout preventer is set, h 封 represents the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom of the well, h 内 represents the vertical distance from the internal blowout preventer tool closest to the bit to the bottom of the well, H represents the vertical distance from the circulation hole to the internal blowout preventer tool closest to the bit, S 环 represents the annular cross-sectional area at the location of the downhole blowout preventer, S 内 represents the internal cross-sectional area at the internal blowout preventer tool, L represents the length of the rubber barrel of the downhole blowout preventer, D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

[0227] In practical applications, for the storage medium of this embodiment, on which a computer program is stored, when the computer program is executed by a controller, the following steps can also be implemented:

[0228] If a well closing operation is monitored, determine the bottom-hole formation pressure according to the monitoring method of the bottom-hole formation pressure described in any one of claims 1-6;

[0229] Determine the density of the kill fluid according to the bottom-hole formation pressure;

[0230] Release the downhole blowout preventer and perform circulating kill based on the density of the kill fluid until the casing pressure at the wellhead meets the preset end condition, and then stop the kill.

[0231] Furthermore, when the computer program is executed by a processor, the following steps can also be implemented:

[0232] Substitute the bottom-hole formation pressure into the preset calculation formula for the density of the kill fluid for calculation to obtain the density of the kill fluid;

[0233] Among them, the calculation formula for the kill fluid density is as follows:

[0234] ρ 压 represents the kill fluid density, P 底 represents the bottom-hole formation pressure, H V represents the vertical depth of the well, ρ 附 represents the additional kill fluid density required based on the well conditions.

[0235] It can be understood that the same or similar parts in the above embodiments can be referred to each other, and the content not detailed in some embodiments can be referred to the same or similar content in other embodiments.

[0236] It should be noted that in the description of the present invention, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" refers to at least two.

[0237] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the technical field to which the embodiments of the present invention belong.

[0238] It should be understood that each part of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following well-known technologies in the art can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0239] Those of ordinary skill in the art of the present technology can understand that all or part of the steps carried by the methods in the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0240] In addition, each functional unit in various embodiments of the present invention may be integrated into a processing module 32, may exist separately as individual physical units, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0241] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc.

[0242] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0243] Although the embodiments disclosed in the present invention are as above, the above content is only an embodiment adopted for the convenience of understanding the present invention and is not used to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains, without departing from the spirit and scope disclosed by the present invention, may make any modifications and changes in the form of implementation and details, but the protection scope of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for monitoring the bottom hole formation pressure, characterized in that, Including: Obtaining the internal pressure of the downhole blowout preventer when the downhole blowout preventer is set after well shut-in, the pressure of the circulation hole of the downhole blowout preventer when a complete circulation is established above the downhole blowout preventer, and the change in the string hanging weight before and after the downhole blowout preventer is set; Substituting the internal pressure of the downhole blowout preventer, the pressure of the circulation hole of the downhole blowout preventer, and the change in the string hanging weight into a pre-constructed bottom-hole formation pressure calculation formula for calculation to obtain the bottom-hole formation pressure; Wherein, the internal pressure of the downhole blowout preventer is determined according to the following steps: Obtaining the standpipe pressure when the downhole blowout preventer is set; Determining the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer; The pressure of the circulation hole of the downhole blowout preventer is determined according to the following steps: Obtaining the wellhead casing pressure before well shut-in; Determining the pressure of the circulation hole of the downhole blowout preventer according to the wellhead casing pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer; The bottom-hole formation pressure calculation formula is: Among them, P 底 represents the bottom hole formation pressure, P 压 represents the internal pressure of the downhole blowout preventer, P 上 represents the pressure of the circulation hole of the downhole blowout preventer, ΔT represents the change in hook load before and after setting the downhole blowout preventer, h 封 represents the vertical distance from the packer rubber barrel in the downhole blowout preventer to the bottom hole, h 内 represents the vertical distance from the nearest internal blowout preventer tool to the bottom hole from the bit, H represents the vertical distance from the circulation hole to the nearest internal blowout preventer tool to the bit, S 环 represents the annular cross-sectional area at the location of the downhole blowout preventer, S 内 represents the internal cross-sectional area at the internal blowout preventer tool, L represents the length of the rubber barrel of the downhole blowout preventer, D represents the inner diameter of the wellbore at the setting position of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

2. The monitoring method of bottom-hole formation pressure according to claim 1, characterized in that Determining the internal pressure of the downhole blowout preventer according to the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer includes: Substituting the standpipe pressure and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset internal pressure calculation formula for calculation to obtain the internal pressure of the downhole blowout preventer; Wherein, the internal pressure calculation formula is: P 压 = P 立 + ρgh 循 ; P 压 represents the internal pressure of the downhole blowout preventer, P 立 represents the standpipe pressure, h 循 represents the distance from the top drive to the circulation hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

3. The monitoring method of bottom-hole formation pressure according to claim 1, characterized in that, Determining the pressure of the circulation hole of the downhole blowout preventer according to the wellhead casing pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer includes: Substituting the wellhead casing pressure before well shut-in and the distance from the top drive to the circulation hole of the downhole blowout preventer into a preset circulation hole pressure calculation formula for calculation to obtain the pressure of the circulation hole of the downhole blowout preventer; Wherein, the circulation hole pressure calculation formula is: P 上 = P 套 + ρgh 循 ; P 上 represents the pressure of the circulating hole of the downhole blowout preventer, P 套 represents the casing pressure at the wellhead before closing the well, h 循 represents the distance from the top drive to the circulating hole of the downhole blowout preventer, ρ represents the density of the drilling fluid, and g represents the acceleration due to gravity.

4. A kill well method, characterized in that, Including: If a well shut-in operation is monitored, determining the bottom-hole formation pressure according to the bottom-hole formation pressure monitoring method according to any one of claims 1-3; Determining the kill fluid density according to the bottom-hole formation pressure; Releasing the downhole blowout preventer and performing circulating kill based on the kill fluid density until the wellhead casing pressure meets a preset end condition, and then stopping the kill.

5. The kill well method according to claim 4, characterized in that, Determining the kill fluid density according to the bottom-hole formation pressure includes: Substituting the bottom-hole formation pressure into a preset kill fluid density calculation formula for calculation to obtain the kill fluid density; Wherein, the kill fluid density calculation formula is: ρ 压 represents the density of the kill fluid, P 底 represents the formation pressure at the bottom of the well, H V represents the vertical depth of the well, ρ 附 represents the additional density of the kill fluid required based on the well conditions.

6. A monitoring device for bottom-hole formation pressure, characterized in that, Including a memory and a controller; A computer program is stored on the memory, and when the computer program is executed by the controller, the steps of the bottom-hole formation pressure monitoring method according to any one of claims 1 to 3 are implemented.

7. A kill well system, characterized in that, Including a kill equipment and the bottom-hole formation pressure monitoring equipment according to claim 6; The bottom-hole formation pressure monitoring equipment is used to implement the steps of the bottom-hole formation pressure monitoring method according to any one of claims 1 to 3 when executed; The kill equipment is used to determine the kill fluid density according to the bottom-hole formation pressure monitored by the bottom-hole formation pressure monitoring equipment; release the downhole blowout preventer, and perform circulating kill based on the kill fluid density until the wellhead casing pressure meets a preset end condition, and then stop the kill.

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