Experimental device for simulating visual well drilling leaking stoppage technological process

Abstract

The invention provides a visual well drilling leaking stoppage process simulation experiment device, which comprises a shaft simulation assembly, a simulation drill rod injection assembly, a leakage channel simulation module and a simulation drilling fluid circulation pipeline, and is characterized in that the shaft simulation assembly is internally provided with a cylindrical structure with an accommodating space, and the shaft simulation assembly is made of a transparent material; the simulation drill rod injection assembly is arranged in the shaft simulation assembly and is made of a transparent material; the leakage channel simulation module is communicated with the shaft simulation assembly; the inlet end and the outlet end of the simulated drilling fluid circulation pipeline are respectively communicated with the shaft simulation assembly; the simulation leakage liquid collection pipeline is communicated with the leakage channel simulation module, visual evaluation can be carried out on various well drilling leakage stoppage technological processes formulated according to different leakage channels, leakage types, drilling fluid performance and shaft environments, well drilling leakage stoppage technological parameters and applicability are optimized, and the well drilling leakage stoppage system is used for guiding the site and improving the well drilling leakage stoppage success rate.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, in particular to a visual drilling plugging process simulation experimental device. Background Art

[0002] Generally, indoor experimental methods are used to simulate the leakage of formations during oil and gas drilling, and they are continuously improved, perfected and popularized. According to the functional characteristics of the plugging evaluation instrument and the experimental simulation parameters, most plugging evaluation instruments can be divided into two generations. The first generation is based on the API static plugging evaluation instrument, using steel balls, fine sand and other fillings to simulate the permeability leakage layer, or using a slotted plate with a fixed seam width to simulate different formulas of plugging slurries to plug the effect of fracture leakage formations, such as API standard plugging experimental device, FA type visual sand bed filter loss instrument, HTHP sand bed filter loss plugging instrument. The second generation of plugging instruments, based on the first generation, further considers the morphology of the fracture surface, roughness and other leakage channel characteristics, uses natural and artificial cores as leakage media, and considers the change of the opening of the fracture under pressure conditions, and adds functions such as plugging slurry circulation and plugging process visualization, which can be collectively referred to as comprehensive plugging instruments. For example, PPA / PPT type permeability plugging instrument, adjustable seam width visual high temperature and high pressure plugging instrument, high temperature and high pressure full diameter core fracture plugging instrument, etc.

[0003] The main function of the leak prevention and plugging experimental device is to select the plugging materials and evaluate the plugging effect of the plugging slurry. It cannot simulate the on-site plugging construction process plan and the adaptability of the process, such as: the location of the leakage (bottom of the well, upper formation), the injection location of the plugging slurry, the injection speed, the retention of the plugging slurry, the replacement speed of the plugging slurry and the wellbore drilling fluid and other parameters. The combined reasons lead to the low plugging success rate. Summary of the invention

[0004] The present invention provides a visual drilling plugging process simulation experimental device, which can realize visual evaluation of various drilling plugging processes formulated for different leakage channels, leakage types, drilling fluid properties, and wellbore environments, and is used to optimize drilling plugging process parameters and applicability, provide guidance at the drilling site, and improve the success rate of drilling plugging.

[0005] In view of this, the present invention proposes a visual drilling plugging process simulation experimental device, comprising: a wellbore simulation component, a cylindrical structure with an accommodating space inside, and the wellbore simulation component is made of a transparent material; a simulated drill pipe injection component, which is arranged inside the wellbore simulation component and is detachably connected to the top of the wellbore simulation component, and the simulated drill pipe injection component is made of a transparent material; a leakage channel simulation module, which is connected to the wellbore simulation component; a simulated drilling fluid circulation pipeline, comprising an inlet end and an outlet end, and the inlet end and the outlet end are respectively connected to the wellbore simulation component; a simulated loss fluid collection pipeline, which is connected to the leakage channel simulation module.

[0006] In some optional embodiments, the wellbore simulation component is made of transparent organic glass, and the wellbore simulation component includes a wellbore body, a top cover and a bottom cover, and the wellbore body is respectively connected to the top cover and the bottom cover.

[0007] In some optional embodiments, the wellbore body includes at least two three-way pipelines and multiple cylindrical pipelines, and any two of the three-way pipelines and the cylindrical pipelines are connected to each other; one of the three-way pipelines is connected to the loss channel simulation module; and the other three-way pipeline is connected to the simulated loss fluid collection pipeline.

[0008] In some optional embodiments, the wellbore body further includes a fixing component, through which any two of the cylindrical pipelines can be connected; the cylindrical pipeline and the three-way pipeline can be connected; and two three-way pipelines can be connected through the fixing component.

[0009] In some optional embodiments, the fixing component is any one of a thread, a flange and a clamp.

[0010] In some optional embodiments, the simulated drilling fluid circulation pipeline includes a simulated drilling fluid inlet pipeline and a simulated drilling fluid outlet pipeline, the simulated drilling fluid inlet pipeline and the simulated drilling fluid outlet pipeline are connected, and the simulated drilling fluid inlet pipeline and the simulated drilling fluid outlet pipeline are respectively connected to one of the three-way pipelines; the lost channel simulation module is connected to the other three-way pipeline.

[0011] In some optional embodiments, the simulated drilling fluid inlet pipeline is provided with a first pressure gauge, a first ball valve, a plunger pump and a drilling fluid sample barrel.

[0012] In some optional embodiments, the simulated drilling fluid outlet pipeline is provided with a second pressure gauge, a second ball valve and a plugging slurry barrel.

[0013] In some optional embodiments, the leakage channel simulation module is a cylindrical tubular string, and a second fixing component is provided at both ends of the cylindrical tubular string; the interior of the cylindrical tubular string is filled with steel balls of different particle sizes, fine sand and gravel; or, the interior of the cylindrical tubular string is filled with cutting plates; or, the interior of the cylindrical tubular string is filled with cores; and a fissile leakage channel simulation device is provided inside the cylindrical tubular string.

[0014] In some optional embodiments, the second fixing component is any one of a thread, a flange and a clamp.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] The visual drilling plugging process simulation experimental device provided by the present invention comprises: a wellbore simulation component, a simulated drill pipe injection component, a leakage channel simulation module, a simulated drilling fluid circulation pipeline and a simulated leakage fluid collection pipeline. The wellbore simulation component has a cylindrical structure with a accommodating space inside, and the wellbore simulation component is made of a transparent material, so that the situation inside the wellbore simulation component can be visually observed; the simulated drill pipe injection component is arranged inside the wellbore simulation component and is detachably connected to the top of the wellbore simulation component. The simulated drill pipe injection component is made of a transparent material, and the simulated drill pipe injection component can be lifted up and lowered in sections for loading and unloading, so as to simulate the drilling process in the oil well, and realize the simulation of injection, holding pressure and waiting for plugging at different positions of the wellbore; the simulated drilling fluid circulation pipeline comprises an inlet end and an outlet end, and the inlet end and the outlet end They are respectively connected to the wellbore simulation components, and the simulated drilling fluid circulation pipeline is used to simulate the injection of drilling fluid into the oil well; the loss channel simulation module is connected to the wellbore simulation component, and the simulated loss fluid collection pipeline is connected to the loss channel simulation module. The loss channel simulation module can simulate the loss channels of carbonate rock, igneous rock developed caves, and large cracks that cannot be bridged; the loss channel simulation module can simulate the loss channels of biological limestone, basalt, and diabase formations with fixed and variable fracture widths; the loss channels formed by natural and artificial cores are then prepared with different concentrations of bridge plugging slurry and solidified gel plugging slurry, and the plugging slurry formula in the pre-formulated plugging plan, the static plugging, pressure plugging, and pressure balance plugging construction processes are verified, and the injection parameters are corrected to improve the applicability of the process.

[0017] The visual drilling plugging process simulation experimental device provided by the present invention simulates and corrects the plugging schemes of permeability leakage, fixed-width fracture leakage, large fractures, cave leakage, and variable-width fracture leakage. The on-site plugging is successful in one time, and the simulation effect is in good agreement with the actual plugging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 A schematic structural diagram of a visual drilling plugging process simulation experimental device provided in one embodiment of the present invention.

[0020] Figure 1 The corresponding relationship between the reference numerals and component names in the figure is:

[0021] 1-wellbore simulation assembly; 11-top cover; 12-bottom cover; 13-first three-way pipeline; 14-second three-way pipeline; 15-cylindrical pipeline; 16-gas source valve stem; 17-hydraulic clamp; 2-simulated drill pipe injection assembly; 3-loss channel simulation module; 4-simulated drilling fluid circulation pipeline; 41-simulated drilling fluid inlet pipeline; 411-first pressure gauge; 412-first ball valve; 413-plunger pump; 414-drilling fluid sample barrel; 42-simulated drilling fluid outlet pipeline; 421-second pressure gauge; 422-second ball valve; 423-plugging slurry barrel; 5-simulated loss fluid collection pipeline; 51-loss fluid collection barrel. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0024] Generally, indoor experimental methods are used to simulate the leakage of formations during oil and gas drilling, and they are continuously improved, perfected and popularized. According to the functional characteristics of the plugging evaluation instrument and the experimental simulation parameters, most plugging evaluation instruments can be divided into two generations. The first generation is based on the API static plugging evaluation instrument, using steel balls, fine sand and other fillings to simulate the permeability leakage layer, or using a slotted plate with a fixed seam width to simulate different formulas of plugging slurries to plug the effect of fracture leakage formations, such as API standard plugging experimental device, FA type visual sand bed filter loss instrument, HTHP sand bed filter loss plugging instrument. The second generation of plugging instruments, based on the first generation, further considers the morphology of the fracture surface, roughness and other leakage channel characteristics, uses natural and artificial cores as leakage media, and considers the change of the opening of the fracture under pressure conditions, and adds functions such as plugging slurry circulation and plugging process visualization, which can be collectively referred to as comprehensive plugging instruments. For example, PPA / PPT type permeability plugging instrument, adjustable seam width visual high temperature and high pressure plugging instrument, high temperature and high pressure full diameter core fracture plugging instrument, etc.

[0025] The main function of the leak prevention and plugging experimental device is to select the plugging materials and evaluate the plugging effect of the plugging slurry. It cannot simulate the on-site plugging construction process plan and the adaptability of the process, such as: the location of the leakage (bottom of the well, upper formation), the injection location of the plugging slurry, the injection speed, the retention of the plugging slurry, the replacement speed of the plugging slurry and the wellbore drilling fluid and other parameters. The combined reasons lead to the low plugging success rate.

[0026] The present invention provides a visual drilling plugging process simulation experimental device, which can realize visual evaluation of various drilling plugging processes formulated for different leakage channels, leakage types, drilling fluid properties, and wellbore environments, and is used to optimize drilling plugging process parameters and applicability, provide guidance at the drilling site, and improve the success rate of drilling plugging.

[0027] The present invention provides a visual drilling plugging process simulation experimental device, which comprises: a wellbore simulation component 1, a simulated drill pipe injection component 2, a leakage channel simulation module 3, a simulated drilling fluid circulation pipeline 4 and a simulated leakage fluid collection pipeline 5. The wellbore simulation component 1 has a cylindrical structure with an accommodating space inside, and the wellbore simulation component 1 is made of a transparent material. The simulated drill pipe injection component 2 is arranged inside the wellbore simulation component 1, and the simulated drill pipe injection component 2 is detachably connected to the top of the wellbore simulation component 1, and the simulated drill pipe injection component 2 is made of a transparent material; the leakage channel simulation module 3 is connected to the wellbore simulation component 1; the simulated drilling fluid circulation pipeline 4 comprises an inlet end and an outlet end, and the inlet end and the outlet end are respectively connected to the wellbore simulation component 1; the simulated leakage fluid collection pipeline 5 is connected to the leakage channel simulation module 3.

[0028] Specifically, the wellbore simulation component 1 is made of transparent organic glass, and the wellbore simulation component 1 includes a wellbore body, a top cover 11 and a bottom cover 12, and the wellbore body is respectively connected to the top cover 11 and the bottom cover 12. The wellbore body at least includes a first three-way pipeline 13, a second three-way pipeline 14 and a plurality of cylindrical pipelines 15, and any two of the first three-way pipeline 13, the second three-way pipeline 14 and the plurality of cylindrical pipelines 15 are connected to each other; the first three-way pipeline 13 is connected to the leakage channel simulation module 3; the second three-way pipeline 14 is connected to the simulated leakage fluid collection pipeline 5.

[0029] Further, 3-5 cylindrical pipelines 15 can be provided, each cylindrical pipeline 15 is a transparent organic glass pipe, the transparent organic glass pipe is proportionally 400mm high, 110mm inner diameter and 120mm outer diameter, and the inner and outer surfaces of the cylindrical pipeline 15 are smooth. The first three-way pipeline 13 is a transparent organic glass three-way structure pipe, and the second three-way pipeline 14 is a transparent organic glass detachable three-way structure pipe. The size of the first three-way pipeline 13 is proportionally 400mm high, 110mm inner diameter and 120mm outer diameter, and the three-way end of the first three-way pipeline 13 is 100mm long, 44mm inner diameter and 54mm outer diameter. The second three-way pipeline 14 is proportionally 400mm high, 110mm inner diameter and 120mm outer diameter, and an opening is set on the side of the second three-way pipeline 14 for connecting the simulated lost liquid collection pipeline 5. The first three-way pipeline 13, the second three-way pipeline 14 and the plurality of cylindrical pipelines 15 are combined in pairs. The second three-way pipeline 14 can be designed according to the experimental scheme and installed at the bottom, the middle and the top to simulate the leakage at different positions of the wellbore. The bottom cover 12 is a solid metal iron disc with an outer diameter of 350mm and a thickness of 20mm. There is a 30mm protrusion on the upper surface and an inner diameter of 120mm, which can be connected to the main organic glass pipe. The top cover 11 is a metal iron with an outer diameter of 140mm and a height of 40mm. There is a 70mm opening in the center that matches the clamp and the simulated drill pipe, and there is an opening next to it for installing the gas injection valve stem. There is an inner buckle or metal joint installed inside that matches the size of the transparent organic glass three-way pipe. The size of the first three-way pipeline 13, the second three-way pipeline 14 and the plurality of cylindrical pipelines 15 is reduced by a ratio of 2:1 to the actual wellbore size, so that the device is miniaturized while ensuring the ratio between the inner diameter of the device and the actual wellbore diameter.

[0030] In some optional embodiments, the wellbore body also includes a first fixing component, and any two cylindrical pipelines 15 can be connected through the first fixing component; the cylindrical pipeline 15 and the first three-way pipeline 13 can be connected through the first fixing component; the first three-way pipeline 13 and the second three-way pipeline 14 can be connected through the first fixing component.

[0031] Further, the three-way ends of the first three-way pipeline 13 are respectively provided with first fixing components. The three-way ends of the second three-way pipeline 14 are also respectively provided with first fixing components. The first fixing component is any one of a thread, a flange and a clamp.

[0032] In some optional embodiments, the simulated drill pipe injection assembly 2 is composed of three to five transparent organic glass pipes with threads or metal joints at both ends, which are installed in pairs. After injection, the simulated drill pipe injection assembly 2 can be lifted up and lowered for loading and unloading in sections to simulate the process of drilling and drilling, and to simulate injection, pressure holding, and waiting for plugging at different positions of the wellbore.

[0033] Furthermore, the dimensions of each component in the drill pipe injection simulation drill pipe injection assembly 2 are reduced and fitted at a ratio of 2:1 based on the actual drilling outer diameter of 127mm and wall thickness of 9.19mm drill pipe, so that the device is miniaturized while ensuring the ratio between the inner diameter of the device and the inner diameter of the actual drill pipe. The simulated drill pipe injection assembly 2 is a transparent organic glass pipe with a length of 400mm, an inner diameter of 54mm, an outer diameter of 64mm, and smooth inner and outer surfaces.

[0034] In some optional embodiments, the leakage channel simulation module 3 is a cylindrical tubular string, and a second fixing component is arranged at both ends of the cylindrical tubular string; a filler is arranged inside the cylindrical tubular string, and the filler is steel balls of different particle sizes, fine sand and gravel; or, the filler is a filling slot plate; or, the filler is a natural or artificial core; or, a fissile leakage channel simulation device is arranged inside the cylindrical tubular string.

[0035] Specifically, one of the modules of the leakage channel simulation module 3 is a cylindrical pipe column, which has a length of 200 mm, an inner diameter of 44 mm, and an outer diameter of 54 mm. Both ends of the cylindrical pipe column are provided with threads, metal clamps, or flange structures.

[0036] One module of the leakage channel simulation module 3 is a cylindrical pipe column with a length of 200 mm, an inner diameter of 44 mm, an outer diameter of 54 mm, and a threaded or metal clamp or flange structure at both ends. No medium needs to be added inside. It is externally connected to a simulated leakage fluid collection pipeline 5. The outlet of the simulated leakage fluid collection pipeline 5 is raised to form a "U"-shaped pipe structure, which is used to simulate leakage channels such as caves and large fractures.

[0037] The second module of the leakage channel module 3 is a cylindrical pipe with a length of 45mm, an inner diameter of 44mm, an outer diameter of 54mm, and threads or metal clamps or flange structures at both ends. The inside of the cylindrical pipe is filled with a slit plate with a fixed seam width, and then connected with a pipe with a length of 200mm, an inner diameter of 44mm, an outer diameter of 54mm, and threads or metal clamps or flange structures at both ends as a liquid guide tube.

[0038] The third module of the leakage channel simulation module 3 is a cylindrical pipe with a length of 100 mm, an inner diameter of 40 mm in the front 50 mm part, an inner diameter of 44 mm in the rear 50 mm part, and an outer diameter of 54 mm. The transparent plexiglass pipe with threads or metal clamps or flange structures at both ends is filled with natural and artificial cores to simulate the leakage formation.

[0039] The fourth module of the leakage channel simulation module 3 is a cylindrical pipe column with a length of 200 mm, an inner diameter of 44 mm, an outer diameter of 54 mm, and a threaded or metal clamp or flange structure at both ends, and a variable fracture leakage channel simulation device is designed inside.

[0040] In some optional embodiments, the simulated drilling fluid circulation pipeline 4 includes a simulated drilling fluid inlet pipeline 41 and a simulated drilling fluid outlet pipeline 42, the simulated drilling fluid inlet pipeline 41 and the simulated drilling fluid outlet pipeline 42 are connected, and the simulated drilling fluid inlet pipeline 41 and the simulated drilling fluid outlet pipeline 42 are respectively connected to the first three-way pipeline 13; the loss channel simulation module 3 is connected to the second three-way pipeline 14.

[0041] In some optional embodiments, the simulated drilling fluid inlet pipeline 41 is provided with a first pressure gauge 411 , a first ball valve 412 , a plunger pump 413 and a drilling fluid sample barrel 414 .

[0042] In some optional embodiments, the simulated drilling fluid outlet pipeline 42 is provided with a second pressure gauge 421 , a second ball valve 422 and a plugging slurry barrel 423 .

[0043] In some optional embodiments, the second fixing component is any one of a thread, a flange and a clamp.

[0044] Specifically, the first pressure gauge 411 and the second pressure gauge 421 are precision pressure gauges with a range of 10MPa. The plunger pump 413 is a bedroom plunger pump, and the displacement is reduced by 1000:1 based on the actual drilling displacement of 10L / s, 20L / s, and 30L / S, so as to miniaturize the device while ensuring the proportional relationship between the working displacement of the device and the actual drilling displacement. The drilling fluid pump has an operating voltage of 220v and an adjustable displacement of 0.1 to 2.0L / min. The drilling fluid sample barrel 414 has a capacity of 30L, the plugging slurry barrel 423 has a capacity of 10L, and the lost fluid collection barrel 51 has a capacity of 5L

[0045] In some optional embodiments, a well is drilled to a high-permeability sandstone formation at a depth of 1643 m using a 215.9 mm drill bit, and the drilling fluid is 1.20 g / cm 3 Increased to 1.25g / cm 3 , occurred 35m 3 / h permeability loss. Analysis shows that the sandstone and conglomerate of the Guantao Formation in the upper 1423m-1525m are loosely cemented and have well-developed stratum pores, which are prone to permeability loss. It is planned to use 25m of bridge plugging slurry with a total concentration of 15% and a maximum particle size of 3.0mm. 3 , inject plugging slurry at the bottom of the leaking layer and implement the pressure plugging measures plan.

[0046] Prepare plugging slurry: According to the plugging scheme, take 4L of on-site circulating drilling fluid and prepare plugging slurry according to the plugging scheme: place the 4L circulating drilling fluid sample barrel 414 on a low-speed agitator, start stirring, and add 5% drilling fluid plugging agent modified plant fiber, 6% drilling fluid plugging agent calcium carbonate fiber BZ-DSA and 4% drilling fluid composite plugging agent in sequence. Stir for no less than 10 minutes after adding each plugging agent. After all the plugging agents are added, stir for 30 minutes and set aside. Prepare plugging slurry consistent with the on-site formula and perform indoor simulated pressure plugging.

[0047] Experimental device installation and plugging process simulation:

[0048] Ⅰ. Select one of the modules of the leakage channel simulation module 3, fill it with 10-20 mesh building sand, simulate the permeability leakage channel of ≤1.0mm, and install it at the tee end of the second tee pipeline 14.

[0049] II. Assemble the wellbore simulation component 1 from bottom to top, press the bottom cover 12, the cylindrical plexiglass tube 1, the transparent plexiglass tee with the leakage channel simulation module 3, the cylindrical plexiglass tube 2, the cylindrical plexiglass tube 3, and the transparent plexiglass tee to simulate the wellbore environment where the leakage layer is not at the bottom of the well.

[0050] III. Install the top cover 11 on the upper part, and install drill pipes to simulate injection pipelines one by one through the holes in the top cover 11, with the depth being at the same level as the leakage simulation channel 1.

[0051] IV. Install the remaining accessories, open the first ball valve 412, open the second ball valve 422, close the outlet ball valve of the leakage channel simulation module 3, start the pump, and inject the circulating drilling fluid taken on site at a speed of 1.8L / min to establish the drilling fluid circulation.

[0052] V. Switch the plunger pump 413 suction line, suck the plugging slurry at a speed of 0.6L / min, inject the prepared plugging drilling fluid, and place the overflow pipeline in the drilling fluid sample barrel 414 to recover the overflowed drilling fluid. After 0.5L of the plugging slurry comes out of the drill pipe simulation device, inject the prepared plugging drilling fluid at a speed of 1.2L / min, and open the outlet ball valve of the simulated leakage channel. After all the plugging slurry is sucked into the pipeline, switch the plunger pump 413 suction line to the drilling fluid sample barrel 414, and continue to displace at a speed of 0.6L / min until the plugging slurry is balanced inside and outside.

[0053] VI. Pull out the drill pipe simulation device until the outlet is above the plugging slurry level, close the first ball valve 412 and the second ball valve 422, pressurize the metal hydraulic clamp 17, and seal the gap between the drill pipe simulation device and the top rod.

[0054] Ⅶ. Open the gas source, slowly increase the pressure, and observe that 15mL of drilling fluid flows out of the outlet. The pressure gauge shows 1MPa. Close the gas source, stabilize the pressure for 10 minutes, the pressure drop is 0.1MPa, and the seepage liquid is about 1mL. Slowly open the valve of the drilling fluid overflow port to release the pressure and observe the plugging status. Close the valve of the drilling fluid overflow port again, slowly open the gas source, and slowly increase the pressure. After observing that 3mL of drilling fluid flows out of the outlet, the pressure gauge shows 1MPa, stabilize the pressure for 10 minutes, and the seepage filtrate is 1.0mL. Continue to increase the pressure, observe that 1mL of drilling fluid flows out of the outlet, the pressure gauge shows 2MPa, stabilize the pressure for 10 minutes, and the seepage filtrate is 0.5mL. Continue to increase the pressure, observe that 0.5mL of drilling fluid flows out of the outlet, the pressure gauge shows 3MPa, continue to stabilize the pressure for 60 minutes, the seepage filtrate is 0mL, and the pressure plugging is completed.

[0055] Ⅸ. After the experiment is completed and the pressure is released, the drilling fluid circulation process is connected again. After the plugging slurry is discharged, the pressure-bearing plugging process is replaced. The plugging test is carried out at a pressure of 3MPa. The pressure drop is 0.1MPa in 30 minutes. 1mL of filtrate is collected to achieve tight sealing and the experimental simulation is completed.

[0056] Simulation effect: Through the visual simulation of the pressure plugging process, the effectiveness of the plugging slurry formula and the correctness of the injection position of the plugging slurry were verified, the plugging slurry injection parameters and the pressure control parameters of the pressure holding process were corrected, and the plugging was successfully implemented on site. The pressure bearing capacity of the wellbore was increased by 3.0MPa, meeting the pressure bearing requirements of the lower drilling construction wellbore. The device visualized the pressure plugging process of using bridge plug plugging slurry to plug the permeable leakage channel on site. Compared with the actual pressure plugging process, the process simulation degree reached a high level.

[0057] In some optional embodiments, a well is drilled with a 215.9mm drill bit to a basalt fracture at a depth of 2554m, and fracture leakage occurs at a rate of 45m3 / h. According to the formation lithology and the leakage rate, it is estimated that the fracture opening is about 2.0mm. It is planned to use 25m3 of multi-fiber bridge plugging slurry with a total concentration of 24% and a maximum material particle size of 2.4mm on site, inject the plugging slurry at the bottom of the leaking layer, and implement the pressure plugging measures.

[0058] Prepare plugging slurry: according to the plugging scheme, take 4L of on-site circulating drilling fluid, prepare plugging slurry according to the plugging scheme: place the 4L circulating drilling fluid sample barrel 414 on a low-speed agitator, start stirring, and add 4% drilling fluid plugging agent composite fiber type I, 6% drilling fluid plugging agent modified plant fiber, 6% drilling fluid plugging agent multiple plant fiber and 8% drilling fluid plugging agent composite fiber type III in sequence. Stir for no less than 10 minutes after adding each plugging agent. After all the plugging agents are added, stir for 30 minutes and set aside. Prepare plugging slurry consistent with the on-site formula and perform indoor simulated pressure plugging.

[0059] Experimental device installation and plugging process simulation:

[0060] Ⅰ. Select leakage channel module 2, fill in 2.00mm parallel seam plate module, simulate 2.00mm crack leakage channel, and install it at the tee end.

[0061] Ⅱ. Assemble the wellbore simulation component 1 from bottom to top, press the bottom cover 12, the three-way plexiglass tube with leakage channel simulation module 3, module one, cylindrical plexiglass tube 1, cylindrical plexiglass tube 2, cylindrical plexiglass tube 3, and three-way plexiglass tube to simulate the wellbore environment of the fracture leakage layer at the bottom of the well.

[0062] III. Install the top cover 11 on the upper part, and install drill pipes to simulate injection pipelines one by one through the holes in the top cover 11, with the depth being at the same level as the leakage simulation channel 2.

[0063] IV. Install the remaining accessories, open the first ball valve 412, open the second ball valve 422, close the outlet ball valve of the leakage channel simulation module 3, start the pump, and inject the circulating drilling fluid taken on site at a speed of 1.8L / min to establish the drilling fluid circulation.

[0064] V. Switch the plunger pump 413 suction line, suck the plugging slurry at a speed of 0.6L / min, inject the prepared plugging drilling fluid, and place the overflow pipeline in the drilling fluid sample barrel 414 to recover the overflowed drilling fluid. After 0.5L of the plugging slurry comes out of the drill pipe simulation device, inject the prepared plugging drilling fluid at a speed of 1.2L / min, and open the outlet ball valve of the simulated leakage channel simulation module 3. After all the plugging slurry is sucked into the pipeline, switch the plunger pump 413 suction line to the drilling fluid sample barrel 414, and continue to displace at a speed of 0.6L / min until the plugging slurry is balanced inside and outside.

[0065] VI. Pull out the drill pipe simulation device until the outlet is above the plugging slurry level, and close the first ball valve 412 and the second ball valve 422. Pressurize the metal hydraulic clamp 17 to seal the gap between the drill pipe simulation device and the mandrel.

[0066] Ⅶ. Open the gas source, slowly increase the pressure, and observe that 150mL of drilling fluid flows out of the outlet. The pressure gauge shows 1MPa. Close the gas source, stabilize the pressure for 10 minutes, the pressure drop is 0.5MPa, and the seepage liquid is about 5mL. Slowly open the valve of the drilling fluid overflow port to release the pressure and observe the plugging status. Close the valve of the drilling fluid overflow port again, slowly open the gas source, and slowly increase the pressure. After observing that 35mL of drilling fluid flows out of the outlet, the pressure gauge shows 1MPa, stabilize the pressure for 10 minutes, and the seepage filtrate is 3.0mL. Continue to increase the pressure, observe that 12mL of drilling fluid flows out of the outlet, the pressure gauge shows 2MPa, stabilize the pressure for 10 minutes, and the seepage filtrate is 0.5mL. Continue to increase the pressure, observe that 1mL of drilling fluid flows out of the outlet, the pressure gauge shows 3MPa, continue to stabilize the pressure for 60 minutes, the seepage filtrate is 0mL, and the pressure plugging is completed.

[0067] Ⅸ. After the experiment is completed and the pressure is released, the drilling fluid circulation process is connected again. After the plugging slurry is discharged, the pressure-bearing plugging process is replaced. The plugging test is carried out at a pressure of 3MPa. The pressure drop is 0.1MPa in 30 minutes. 1mL of filtrate is collected to achieve tight sealing and the experimental simulation is completed.

[0068] Simulation effect: Through visual simulation of the pressure plugging process, it was observed that the plugging slurry smoothly entered the leaking layer, and the material formed a tight seal in the crack, verifying that the plugging slurry injection position was correct, the bridge plug plugging slurry formula matched the leakage channel reasonably, and it smoothly entered the leakage layer during the squeezing process; the plugging slurry injection parameters and the pressure parameter control method during the pressure holding process were corrected, and the plugging was successfully implemented on site. The device visualized the pressure plugging process of the fracture leakage channel using the bridge plug plugging slurry on site. Compared with the actual pressure plugging process, the process simulation degree reached a high level.

[0069] In some optional embodiments, a well was drilled in the Ordovician carbonate formation of the buried hill using a 215.9mm drill bit and a density of 1.03g / cm3 of clear water and solid-free drilling fluid. At a well depth of 2674m, the drill bit was emptied for 1.5m, and a loss of return occurred. When the pump was stopped, the wellbore liquid level was 180m to 200m away from the wellhead. There was basically no pump pressure during the injection of clear water and bridge plugging slurry, and the drilling fluid level varied between 150m and 250m from the wellhead. This indicates that the drilling encountered a cave-like leakage channel with an opening of ≥10cm, and the bridge plugging agent could not bridge it. It is planned to use cement plugging slurry and a pressure balance plugging process to implement plugging.

[0070] Prepare plugging slurry: According to the plugging plan, take 4L of on-site circulating drilling fluid, prepare 1.85g / cm3 cement plugging slurry with the same density as the on-site formula according to the plugging plan, and keep it for later use. Carry out indoor simulated plugging.

[0071] Experimental device installation and plugging process simulation:

[0072] Ⅰ. Select the leakage channel simulation module 3, without adding any medium, and install it at the tee end to simulate the cave leakage channel.

[0073] II. Assemble the wellbore simulation component 1, from bottom to top, press the bottom cover 12, the three-way plexiglass tube with the leakage channel simulation module 3, the cylindrical plexiglass tube, the cylindrical plexiglass tube, the cylindrical plexiglass tube, and the three-way plexiglass tube to simulate the wellbore environment of the karst leaking layer.

[0074] III. Install the top cover 11 on the upper part, and install drill rods one by one through the holes in the top cover 11 to simulate the injection pipeline. The depth is 20 cm higher than the horizontal plane of the simulated lost fluid collection pipeline 5. Considering the high density of the plugging slurry, it naturally sinks to the leaking layer.

[0075] IV. Install the remaining accessories, open the first ball valve 412, open the second ball valve 422, close the outlet ball valve of the leakage channel simulation module 3, start the pump, inject clean water at a speed of 1.8L / min, and establish circulation.

[0076] V. Stop the pump, raise the outlet of the leakage channel simulation module 3 to 20 cm below the overflow port, and then open the outlet ball valve to form a "U"-shaped pipe structure with the wellbore simulation module to simulate the actual wellbore after the pump is stopped. The wellbore liquid level is 180m to 200m away from the wellhead, and after the pump is turned on, the wellbore liquid level remains stable.

[0077] VI. Switch the plunger pump 413 suction line, inject the prepared cement plugging slurry at a speed of 0.6L / min, and recover the lost clean water through the outlet of the leakage channel simulation module 3. After 0.5L of the plugging slurry leaves the drill pipe simulation device, inject the prepared cement plugging slurry at a speed of 1.2L / min. After all the plugging slurry is sucked into the pipeline, switch the plunger pump 413 suction line to the drilling fluid sample barrel 414, and continue to displace at a speed of 0.6L / min until the plugging slurry is balanced inside and outside.

[0078] Simulation effect: Through visual observation, since cement plugging slurry belongs to a dispersed system and the wellbore clean water has low viscosity and low shear, the cement plugging slurry and the wellbore clean water are seriously mixed during the injection process, which reduces the concentration of cement plugging slurry; during the waiting process, due to the difference in density between cement plugging slurry and clean water, the lower part of the cement plugging slurry and the clean water contact interface are continuously replaced (cement slurry sinks), and bypass flow is formed, and the upper cement slurry is displaced and moved upward, unable to stay in the first position of the simulation channel, solidify and seal, and the experiment is stopped. The next step requires the wellbore clean water adhesion and shear performance, plugging slurry adhesion and shear and density parameters, adjust the construction process, and then conduct simulation experiments.

[0079] Adjustment measures: Prepare 10L of xanthan gum aqueous solution with a concentration of 0.5%, a funnel viscosity of 62s and a density of 1.01g / cm3 as a pre-fluid to replace the clean water near the leaking layer in the wellbore without being replaced with the clean water, thereby providing a retention environment for the plugging slurry; prepare a solidified gel plugging slurry with a funnel viscosity of 73s and a density of 1.02g / cm3 to achieve retention in the xanthan gum solution without being replaced or diluted.

[0080] Experimental device installation and plugging process simulation:

[0081] Ⅰ. Select module 1 of the leakage channel simulation module 3, without adding any medium, and install it at the tee end to simulate the cave leakage channel.

[0082] II. Assemble the wellbore simulation component 1, from bottom to top, press the bottom cover 12, the three-way plexiglass tube with the leakage channel simulation module 3, the cylindrical plexiglass tube, the cylindrical plexiglass tube, the cylindrical plexiglass tube, and the three-way plexiglass tube to simulate the wellbore environment of the karst leaking layer.

[0083] III. Install the top cover 11 on the upper part, and install drill pipes to simulate injection pipelines one by one through the holes in the top cover 11, with the depth being at the same level as the leakage simulation channel 1.

[0084] IV. Install the remaining accessories, open the first ball valve 412, open the second ball valve 422, close the outlet ball valve of the leakage channel simulation module 3, start the pump, inject clean water at a speed of 1.8L / min, and establish circulation.

[0085] V. Stop the pump, raise the outlet of the simulated lost liquid collection pipeline 5 to 20 cm below the overflow port, and then open the outlet ball valve of the simulated lost liquid collection pipeline 5 to form a "U"-shaped pipe structure with the wellbore simulation component 1 to simulate the actual wellbore after the pump is stopped. The wellbore liquid level is 180m to 200m away from the wellhead, and after the pump is turned on, the wellbore liquid level remains stable.

[0086] VI. Switch the plunger pump 413 suction line, inject the prepared xanthan gum solution at a speed of 0.6L / min, and recycle the lost clean water at the outlet of the leakage simulation channel 1 pipeline. After 0.5L of the xanthan gum solution exits the drill pipe simulation device, inject the prepared xanthan gum solution at a speed of 1.2L / min. After 70% of the xanthan gum solution is sucked into the pipeline, switch the plunger pump 413 suction line to the solidified gel plugging slurry barrel 423, and continuously inject the solidified gel plugging slurry. After all the plugging slurry is sucked into the pipeline, switch the plunger pump 413 suction line to the xanthan gum solution, and continue to replace the remaining 30% of the xanthan gum solution with the solidified gel plugging slurry at a speed of 0.6L / min until the internal and external balance.

[0087] VII. Pull out the drill pipe simulation device until the outlet is above the plugging slurry level, and close the overflow ball valve. Pressurize the metal hydraulic clamp 17 to seal the gap between the drill pipe simulation device and the push rod. Start the pump at a speed of 0.6L / min to replace the wellbore plugging slurry and fill the leakage channel.

[0088] Ⅶ. Install a heating jacket outside the leakage channel and heat it for 8 hours to form a solidified seal.

[0089] Ⅸ. After solidification and plugging, connect the drilling fluid circulation process, discharge the plugging slurry from the wellbore, and then replace the pressure plugging process. Perform a plugging test at a pressure of 3MPa, with a pressure drop of 0MPa in 30min and 0mL of filtrate collected to achieve sealing of the cave channel. The experimental simulation is completed.

[0090] Simulation effect:

[0091] Ⅰ. Through visual observation, after the xanthan gum solution leaves the drilling tool simulation device, it is retained in equilibrium near the leaking layer, with a clear boundary with the clean water and no replacement occurs; the solidified gel plugging slurry can be retained in equilibrium in the xanthan gum solution, with a clear boundary with the xanthan gum solution and no replacement occurs; the xanthan gum solution and plugging slurry can be displaced to the appropriate position of the wellbore and leaking layer as needed, and solidified and sealed by heating, achieving good experimental results.

[0092] Ⅱ. For the wells with large cracks and cave-like leaks, the solidifying gel plugging process was visualized for simulation, adjustment and optimization. Compared with the actual solidifying gel plugging process, the process simulation degree was high.

[0093] III. The adjusted solidified gel plugging process was implemented on site, and the plugging was successful in one go. The wellbore pressure bearing capacity was increased by 5.0MPa, meeting the wellbore pressure bearing requirements for the lower drilling construction.

[0094] In some optional embodiments, a well was drilled to a depth of 3143m in basalt using a 215.9mm drill bit, with a displacement of 2.04m3 / h, and a leakage rate of 33m3 / h occurred. After stopping the pump and observing it statically, the drilling fluid level was 50m from the wellhead, and there was no more leakage. After two bridge plug pressure plugging and one cement plugging, the leakage complexity was not resolved. Analysis showed that it was basalt fracture leakage, and the fracture opening varied between 0 and 2.0mm with the change of wellbore pressure, and there were dominant leakage channels and micro leakage channels.

[0095] Preparation of plugging slurry: Based on the experience of two bridge plug pressure plugging and one cement plugging in this well, it was decided to use low-density solidified gel pressure plugging method for plugging. The plugging slurry preparation plan is as follows: prepare solidified gel plugging slurry with funnel viscosity of 50s and density of 1.30g / cm3 balanced with the density of drilling fluid, add small-particle bridge plug plugging agent for bridging and retention, and then add high water loss gel to adjust the medium pressure water loss of the plugging slurry to about 180mL / 7.5min. In the process of pressure, the gel loses water and enriches it, supports and fills the cracks, and forms a high-strength solidified plugging layer.

[0096] Experimental device installation and plugging process simulation:

[0097] Ⅰ. Select module 4 of the leakage channel simulation module 3, fill in the variable parallel slit plate module, simulate the crack leakage channel with an opening of 0 to 2.00 mm under 0-2MPa conditions, and install it at the tee end.

[0098] II. Assemble the wellbore simulation component 1, from bottom to top, press the bottom cover 12, the three-way plexiglass tube with the leakage channel simulation module 3, the cylindrical plexiglass tube, the cylindrical plexiglass tube, the cylindrical plexiglass tube, and the three-way plexiglass tube to simulate the wellbore environment of the basalt variable fracture leakage channel.

[0099] III. A top cover 11 is installed on the upper part, and drill pipes are installed one by one through the holes in the top cover 11 to simulate the injection pipeline, and the depth is at the same level as the leakage channel simulation module 3.

[0100] IV. Install the remaining accessories, open the first ball valve 412, open the second ball valve 422, close the outlet ball valve of the leakage channel simulation module 3 and module 4, start the pump, and inject the circulating drilling fluid taken on site at a speed of 1.8L / min to establish the drilling fluid circulation.

[0101] V. Switch the plunger pump 413 suction line, suck the plugging slurry at a speed of 0.6L / min, inject the prepared plugging drilling fluid, and place the overflow pipeline in the drilling fluid sample barrel 414 to recover the overflowed drilling fluid. After 0.5L of the plugging slurry comes out of the drill pipe simulation device, inject the prepared plugging drilling fluid at a speed of 1.2L / min, and open the outlet ball valve of the simulated leakage channel. After all the plugging slurry is sucked into the pipeline, switch the plunger pump 413 suction line to the drilling fluid sample barrel 414, and continue to displace at a speed of 0.6L / min until the plugging slurry is balanced inside and outside.

[0102] VI. Pull out the drill pipe simulation device until the outlet is above the plugging slurry level, close the injection port valve and the overflow port valve, pressurize the metal hydraulic clamp 17, and seal the gap between the drill pipe simulation device and the mandrel.

[0103] Ⅶ. Open the gas source, slowly increase the pressure, and observe that about 75mL of drilling fluid flows out of the outlet. The pressure gauge shows 0.5MPa and the crack opening is 1.0mm. Close the gas source, stabilize the pressure for 3min, the pressure drop is 0.5MPa, and the seepage liquid is about 45mL. Slowly open the valve of the drilling fluid overflow port to release the pressure, observe the plugging state, the crack opening is 0.3mm, and most of the internal plugging agent is discharged. Close the valve of the drilling fluid overflow port again, slowly open the gas source, and slowly increase the pressure. After observing that 135mL of drilling fluid flows out of the outlet, the pressure gauge shows 1.2MPa and the crack opening is 2.0mm. Tighten the crack opening fixing screw. Continue to increase the pressure, observe that 35mL of drilling fluid flows out of the outlet, the pressure gauge shows 2MPa, stabilize the pressure for 10min, and the seepage filtrate is 65mL. Continue to increase the pressure, observe that 65mL of drilling fluid flows out of the outlet, the pressure gauge shows 3MPa, close the gas source, wrap the variable fracture simulation module with the heating sleeve, heat it to 80℃, and hold the pressure for 6h. During the process of holding the pressure and waiting for condensation, once the pressure drops to 1.5MPa, the gas source is turned on to increase the pressure to 3.0MPa. The pressure is increased 6 times during the process, and a total of 30mL of filtrate is collected.

[0104] Ⅸ. After heating and pressurizing for plugging for 6 hours, release the pressure and observe that the crack opening is 2.0mm, and the plugging material fills the crack. Then connect the drilling fluid circulation process, discharge the plugging slurry, and then change the pressure plugging process to test the plugging under pressure of 3MPa. The pressure drop is 0MPa in 30 minutes, and the filtrate is 0mL. The sealing plugging is achieved, and the solidified plugging segment plug-fracture stable state is formed, and the experimental simulation is completed.

[0105] Simulation effect: Through the visualization simulation of the low-density solidified gel pressure plugging process for the well leakage with variable fracture-type leakage channels, it was observed that the plugging slurry was full of cracks, and the pressure was held under a certain pressure and temperature to solidify, and the solidified plugging section-crack stable state was achieved indoors, and the plugging pressure capacity was 3.0MPa. The adjusted low-density solidified gel plugging process was implemented on site, and the plugging was successful once, and the wellbore pressure capacity was increased by 5.0MPa, meeting the wellbore pressure requirements for the lower drilling construction.

[0106] In the present invention, the term "plurality" means at least two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0107] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0108] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A visual drilling plugging process simulation experimental device, characterized in that: include: A wellbore simulation component (1) having a cylindrical structure with a receiving space inside, wherein the wellbore simulation component (1) is made of a transparent material; A simulated drill pipe injection assembly (2) is arranged inside the wellbore simulation assembly (1) and is detachably connected to the top of the wellbore simulation assembly (1); the simulated drill pipe injection assembly (2) is made of a transparent material; A leakage channel simulation module (3) is connected to the wellbore simulation component (1); A simulated drilling fluid circulation pipeline (4), comprising an inlet end and an outlet end, wherein the inlet end and the outlet end are respectively connected to the wellbore simulation component (1); The simulated lost fluid collection pipeline (5) is in communication with the lost fluid channel simulation module (3).

2. The visual drilling plugging process simulation experimental device according to claim 1 is characterized in that: The wellbore simulation component (1) is made of transparent organic glass and comprises a wellbore body, a top cover (11) and a bottom cover (12); the wellbore body is respectively connected to the top cover (11) and the bottom cover (12).

3. The visual drilling plugging process simulation experimental device according to claim 2 is characterized in that: The wellbore body at least comprises a first three-way pipeline (13), a second three-way pipeline (14) and a plurality of cylindrical pipelines (15), and any two of the first three-way pipeline (13), the second three-way pipeline (14) and the plurality of cylindrical pipelines (15) are connected to each other; The first three-way pipeline (13) is connected to the lost channel simulation module (3); The second three-way pipeline (15) is connected to the simulated lost fluid collection pipeline (5).

4. The visual drilling plugging process simulation experimental device according to claim 3 is characterized in that: The wellbore body also includes a first fixing component, and any two of the cylindrical pipelines (15) can be connected via the first fixing component; the cylindrical pipeline (15) and the first three-way pipeline (13) can be connected via the first fixing component; and the first three-way pipeline (13) and the second three-way pipeline (14) can be connected via the first fixing component.

5. The visual drilling plugging process simulation experimental device according to claim 4 is characterized in that: The first fixing component is any one of a thread, a flange and a clamp.

6. The visual drilling plugging process simulation experimental device according to claim 3 is characterized in that: The simulated drilling fluid circulation pipeline (4) comprises a simulated drilling fluid inlet pipeline (41) and a simulated drilling fluid outlet pipeline (42), the simulated drilling fluid inlet pipeline (41) and the simulated drilling fluid outlet pipeline (42) are connected, and the simulated drilling fluid inlet pipeline (41) and the simulated drilling fluid outlet pipeline (42) are respectively connected to the first three-way pipeline (13); The lost channel simulation module (3) is in communication with the second three-way pipeline (14).

7. The visual drilling plugging process simulation experimental device according to claim 6 is characterized in that: The simulated drilling fluid inlet pipeline (41) is provided with a first pressure gauge (411), a first ball valve (412), a plunger pump (413) and a drilling fluid sample barrel (414).

8. The visual drilling plugging process simulation experimental device according to claim 7 is characterized in that: The simulated drilling fluid outlet pipeline (42) is provided with a second pressure gauge (421), a second ball valve (422) and a plugging slurry barrel (423).

9. The visual drilling plugging process simulation experimental device according to claim 1 is characterized in that: The leakage channel simulation module (3) is a cylindrical pipe column, and second fixing components are arranged at both ends of the cylindrical pipe column; A filler is arranged inside the cylindrical pipe string, and the filler is steel balls of different particle sizes, fine sand and gravel; or, the filler is a filling slot plate; or, the filler is a natural or artificial core; or, a fissile leakage channel simulation device is arranged inside the cylindrical pipe string.

10. The visual drilling plugging process simulation experimental device according to claim 9 is characterized in that: The second fixing component is any one of a thread, a flange and a clamp.

Images